Fuel Oil Supply System from a Remote Source Including Recirculated Heating of Fuel Oil and Supplemented Supply Pressure

Abstract

A fuel oil supply system for a portable fuel oil consuming device, representatively a portable oil fired construction heater includes supply and return fuel lines in communication with a remote fuel container in an anti-siphon configuration. One or more electrical heaters heat the fuel lines adjacent an integral pump of the consuming device. The fuel lines communicate with a partitioned volume of fuel within the container which is heated relative to a remaining volume as the fuel circulates. The pump and a combustion air blower of the device are located together with the heaters within an enclosure on the device such that air is drawn into the enclosure over the heaters and heat conducting surfaces of the pump by the blower for directing heated air through a combustion air duct of the blower which surrounds the burner and a main fuel line from the pump to the burner.

Description

This application is claims the benefit under 35 U.S.C. 119(e) of U.S. provisional application Ser. No. 61/437,439, filed Jan. 28, 2011, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a fuel oil system for supplying fuel oil for consumption from a remote source to a portable fuel oil consuming device, representatively a portable oil fired construction heater, from a container located remote or separated from the device such that the hoses of the system are exposed to possible injury, and includes one or more electrical heaters for heating one or both of the portable heater pump supply and return lines to and from the entry and exit in the container and around which the fuel oil is constantly recirculated with heat exchange occurring between the supply and return lines and some mixing of fuel oil and heat recovery occurring at the exit and entry in the container, such that heat is conserved and dispersed throughout the system, and with the filter and pump manifold and the electric heaters located in an enclosure, and with a combustion air blower located in and constantly drawing air through the compartment and over the heaters and heat conducting surfaces of the filter and pump manifold and delivering heated air to and through the burner blast tube and around the fuel oil consumption supply branch and nozzle of the system located in the burner blast tube.

BACKGROUND

A known problem with portable fuel fired equipment, for example portable construction type heaters is the poor reliability under extreme cold conditions, which are representatively 0 degC to −50 degC, under all three of the different operational states that apply to portable fuel consuming equipment, especially portable oil fired heaters. Both ‘heating oil’ and ‘diesel’ have the same problems as described herein. The only difference being only a coloring agent to indicate that road tax has been paid on diesel. Sometimes diesel is also used for temporary heating as the same tanks are used for fuel for both portable on-site and mobile on-road equipment.

Operating fuel fired equipment in cold climates represents the last major unpredictably variable cost component, because of poor reliability, of construction in situations where diesel oil/fuel oil is the only fuel available for winter construction projects, typically ‘up north’, where projects typically are quite large, and winters are long and very cold.

The three phases of utilization on site are:

1. Initial startup, of portable heaters, the intended heat source for the site, and other fuel consuming equipment such as portable generator sets driven by diesel engines, the intended electrical supply for the site, that, along with their fuel supplies, have been cold soaked to ambient temperatures.

The site may be isolated with no electrical distribution grid serving the area, and no fuel except heating oil/diesel being distributed in the area. This is a common condition in ‘northern’ applications. However, it can be presumed that a single 15 amp AC service can be made available from a small portable generator brought on to the site, or, from another improvised source, by the parties doing the initial startup, and who are accustomed to initial startups under these circumstances. Historically, the starting of oil fired heaters begins to become significantly problematical at −10 degC with problematical initial starts progressively worsening to about 50% at −30 degC.

2. Ongoing operation, involving the routine starting and stopping of heaters and other equipment once the site is active.

In the case of portable heaters, this may involve space temperature thermostat control, routine starting and stopping as work is commenced in the morning and ceases at the end of the day or over weekends, with the starting and stopping being done by security staff or others with no expertise with the equipment. Also, some forms of fuel problems are progressive while in operation while others are accumulative while not in operation. Both of these situations lend themselves to difficult restarts and/or nuisance shutdowns while the equipment is being routinely employed.

3. Standby, temporarily out of operation awaiting routine maintenance or service. This is a situation with portable heaters where relatively routine service and maintenance usually performed on-site, becomes very problematical as above, because of complications that arise due to the heaters cooling down while off to ambient under extreme cold conditions, which, because of problematical restarts, prevents the normal on-off checkout required to identify problems and enable performance of required maintenance and service on-site.

The immediate causes of unreliability involves the effects of below freezing temperatures on liquid fuel oil, which must be pressurized, atomized and vaporized to an adequate degree in order to ignite, and the complications that variability of quality and contamination commonly encountered with fuel oil, have on that process—as well as the effects on the conveying of fuel from a storage tank through the fuel manifold components, to a two-line pump, and then returned to the tank, with a non-recirculating branch which supplies the nozzle for fuel combustion during heat-on cycles.

In addition, with diesel engine driven portable equipment stationed on site such as generator sets, fuel supply difficulties and failures may occur due to marginal or inadequate suction of the integral oil feed pump when the oil source is altered from an integral trailer mounted tank to a ground mounted remote tank because this may add to the system the resistance of an anti-siphon valve installed at the remote tank as a safety measure and the additional height of lift from ground level to the trailer.

There is always a degree of water contamination and possibly traces of bio-diesel, even in diesel fuel rated as ‘clear’. As well, there may be particles of rust and unidentifiable ‘sludge’ on the bottom of the tank that can be disturbed into flow, depending on the age and cleanliness of the fuel container the fuel is in and has passed through. Water content increases over time as temperature varies and air expands and contracts causing moisture bearing air to breath in and out of the tank air vent and condensation to occur on inner tank walls. Bio-diesel is hygroscopic and will directly absorb water from air and also readily degrade due to bacterial action into a thick curd. The quality of the diesel itself may vary with more or less paraffin content that precipitates out as temperatures drops below −10 C as wax particles in suspension that will adhere to surfaces on contact when in flow. At temperatures below 0 C, the water contamination may take several forms; it will float in suspension as ice crystals, if undisturbed it may float as super-cooled droplets that will turn into ice on contact with surfaces when put into flow, and over an undisturbed period above freezing temperature will separate out and freeze into solid masses wherever it pools. Also, the fuel itself will become inherently more difficult to ignite because of increase in viscosity and decrease in vaporization as temperature falls.

The combined effects of all or some of this, is that blockages of fuel, or pressure reducing impediments to flow, which will complicate problems with marginal or inadequate integral oil pump suction, may occur at many points in the system including;

• • accumulation of ice surrounding the inlet to the system while not in operation, due to water pooled at the bottom of the tank being frozen into a block;
  • freezing while not in operation, of pooled water in the filter and pump housings;
  • clogging of the nozzle and failure of fuel flow on startup, when ice crystal are driven into and clog the fine opening of the nozzle;
  • deterioration of the fine atomization of fuel at the nozzle necessary to create vaporization and failure of ignition, due to sluggishness of the fuel and reduced or delayed achievement of pressure at the nozzle;
  • accumulation of icing while in operation, due to impingement on a strainer if placed at the inlet, or, on the inner works of the anti-siphon valve;
  • collection while in operation, in the filter at the fuel consuming device, especially of wax particles but also of ice crystals;

With fuel consuming equipment other than heaters that is diesel engine driven such as portable generator sets, the suction of their integral fuel pumps or injectors may be inadequate to dependably crack open the anti-siphon valve and to raise the fuel from the safety fueler hose at ground level.

It should be noted that some of these factors causing unreliability occur under below freezing conditions while the heater is ‘on’, in operation, and others while the heater is ‘off’, out of operation.

There are many additives to fuel to improve ‘performance’, but the effectiveness of these diminishes as temperatures fall, some being ineffective unless added before ice has formed as the temperature goes down. None have any effect on reducing the temperature that wax is precipitated out of the fuel or on removing it once deposited.

SUMMARY OF THE INVENTION

Although other objects will become apparent within the accompanying disclosure, it is one object of the fuel oil supply system of the present invention to provide or enable an improvement in the reliability for portable fuel fired equipment fuelled by a remote source of fuel oil during all phases of its utilization and under extreme cold conditions on construction or equivalent sites, as is normally the case when ambient temperatures are ranging above 0 degC/32 degF—the freezing point of water. While the benefits of the present invention are greatest in extreme cold conditions, the use of all or some aspects of this technology, will improve reliability of portable oil-fired heaters anywhere temperatures drop below freezing.

According to one aspect of the present invention there is provided a fuel oil supply system in combination with a portable fuel fired heater for supplying fuel oil from a remote fuel container independent of the portable fuel fired heater wherein the portable fuel fired heater comprises:

a burner;

a combustion air blower arranged to deliver combustion air to the burner;

a pump having an inlet arranged for connection to a fuel supply line in communication with a remote fuel container, a return outlet arranged for connection to a return line in communication with the remote fuel container, and a consumption outlet in communication with a main fuel line between the pump and the burner so as to be arranged to deliver fuel to the burner; and

a combustion duct communicating from the blower to the burner and receiving the main fuel line extending therethrough;

wherein the fuel oil supply system comprises:

• • a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device;
  • a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container;
  • an enclosure surrounding the pump and the combustion air blower, the enclosure including an air inlet arranged to receive combustion air for the blower therethrough into the enclosure and;
  • a fuel heater supported within the enclosure in heat exchanging relationship with at least one of the supply and return lines in proximity to the pump.

Preferably the system further comprises a controller operatively connected to the portable fuel fired heater and the fuel oil supply system in which the controller is adapted to operate in a standby mode, a normal heating mode and a pre-start-up mode.

Preferably in the standby mode, the fuel heater is activated, a valve in series between the consumption outlet of the pump and the burner is closed, the pump is activated such that fuel oil is circulated between the remote fuel container and the fuel consuming device through the supply and return lines, and the blower is activated such that air heated within the enclosure by the fuel heater is drawn into the combustion duct for thawing the main fuel line extending therethrough.

Preferably in the normal heating mode, the pump is activated, the blower is activated, a valve in series between the consumption outlet of the pump and the burner is open such that the burner can be ignited, and the fuel heater is inactive.

Preferably in the pre-start-up mode the auxiliary fuel heater is active, the pump is inactive, and the blower is inactive.

Preferably the pump, the blower, the fuel heater collectively consume substantially equal to or less than 12.5 amps in each of the standby mode, the normal heating mode, and the pre-start-up mode.

Alternatively, when the system further comprises an air heater supported within the enclosure in heat exchanging relationship with the air inlet, the controller is preferably adapted to operate in the pre-start-up mode such that the fuel heater is inactive, the pump is inactive, the blower is inactive, and the auxiliary air heater is active. The air heater and the fuel heater can be active simultaneously if more than one 15 amp service is available on site.

The fuel heater preferably includes a first heating element in communication with the return line in proximity to the pump, and optionally a second heating element in communication with the supply line in proximity to the pump.

Preferably the return line extends substantially concentrically through the supply line from the outlet end to the inlet end of the supply line. The concentric arrangement is one example of how the supply line and the return line may be effectively joined in a heat exchanging relationship along respective lengths thereof between the respective inlet and outlet ends.

Optionally the system may further comprise an adjustable throttling valve in series with the return line. This throttling valve can be arranged such that it will not fully close and thus never fully block flow through the return line.

Preferably the system further comprises a baffle member arranged to be supported in the remote fuel container so as to define a partitioned volume in fluid communication with a remaining volume within the remote fuel container in which both the inlet end of the supply line and the outlet end of the return line are in fluid communication with the partitioned volume. The baffle member may be generally tubular in an upright orientation such that the partitioned volume is substantially columnar in shape, and may include ports communicating through the baffle member adjacent opposing top and bottom ends.

The baffle member may be further arranged to define a lower partitioned volume adjacent a bottom end of the remote fuel container in which the lower partitioned volume is arranged to only communicate with a remaining volume within the remote fuel container at a fluid communicating location spaced upwardly from the bottom end of the remote fuel container. Preferably the inlet end of the supply line is arranged to be located within the lower partitioned volume below the fluid communicating location. The upward position of the communicating location relative to the bottom of the container and relative to the supply inlet provides a dam effect which prevents water accumulation and/or ice formation at the bottom of the container from plugging or entering into the supply line while also providing an opportunity for air entrapped in the fuel oil to rise upwardly and away from the supply inlet within the partitioned volume.

The pump is preferably adapted to direct more than twice a volume of fuel through the return outlet than the consumption outlet. For example 85% of the volume may be directed to the return outlet and 15% of the volume may be directed to the consumption outlet.

When the portable fuel fired heater further comprises a main heater duct receiving air to be heated therethrough, the fuel supply system may further comprise a diversion port communicating from the main heater duct to the enclosure about the pump and the blower.

Preferably the fuel heater is supported in heat exchanging relationship with the air inlet of the enclosure.

In some instances the system may further comprise an auxiliary air heater supported within the enclosure separate from the fuel heater in heat exchanging relationship with the air inlet of the enclosure. The auxiliary air heater could be used in place of the fuel heaters during the prestart-up mode to more quickly heat the air within the enclosure. Alternatively, the auxiliary air heater may be used in addition to the fuel heaters during the prestart-up mode where additional electric service is available on site.

When the system further comprises an anti-siphon device supported in series with supply line in which the anti-siphon device comprises a valve member which is biased to a closed position and which is only arranged to be opened by a prescribed reduction in pressure in the supply line which is greater than a reduction in pressure in the supply line associated with activation of the integral pump, the system may further comprise an auxiliary booster pump arranged for operation in series with the supply line. In this instance, a reduction in pressure in the supply line associated with activation of both the booster pump and the integral pump is preferably greater than the prescribed reduction in pressure of the anti-siphon valve.

According to a second aspect of the present invention there is provided a fuel oil supply system for conducting fuel oil between a remote fuel container and a fuel consuming device including a pump having an inlet, a consumption outlet, and a return outlet, the fuel oil supply system comprising:

a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device;

a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container;

a fuel heater in communication with at least one of the supply and return lines; and

a baffle member arranged to be supported in the remote fuel container so as to define a partitioned volume in fluid communication with a remaining volume within the remote fuel container;

wherein the inlet end of the supply line and the outlet end of the return line are in fluid communication with the partitioned volume.

According to a further aspect of the present invention there is provided a fuel oil supply system for conducting fuel oil between a remote fuel container and a fuel consuming device including a pump having an inlet, a consumption outlet, and a return outlet, the fuel oil supply system comprising:

a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device;

a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container;

a fuel heater in communication with at least one of the supply and return lines; and

a baffle member arranged to be supported in the remote fuel container so as to define a lower partitioned volume adjacent a bottom end of the remote fuel container;

the lower partitioned volume being arranged to only communicate with a remaining volume within the remote fuel container at a fluid communicating location spaced upwardly from the bottom end of the remote fuel container; and

the inlet end of the supply line being located within the lower partitioned volume below the fluid communicating location.

According to yet another aspect of the present invention there is provided a fuel oil supply system in combination with a portable fuel fired heater for supplying fuel oil from a remote fuel container independent of the portable fuel fired heater wherein the portable fuel fired heater comprises:

a burner;

a combustion air blower arranged to deliver combustion air to the burner;

a pump having an inlet arranged for connection to a fuel supply line in communication with a remote fuel container, a return outlet arranged for connection to a return line in communication with the remote fuel container, and a consumption outlet in communication with a main fuel line between the pump and the burner so as to be arranged to deliver fuel to the burner;

a fuel filter in series with the inlet of the pump; and

a combustion duct communicating from the blower to the burner and receiving the main fuel line extending therethrough;

wherein the fuel oil supply system comprises:

• • a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device;
  • a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container;
  • the supply line and the return line being joined in a heat exchanging relationship along respective lengths thereof between the respective inlet and outlet ends;
  • a baffle member arranged to be supported in the remote fuel container so as to define a partitioned volume in fluid communication with a remaining volume within the remote fuel container;
  • the inlet end of the supply line and the outlet end of the return line being in fluid communication with the partitioned volume;
  • an enclosure surrounding the pump, the fuel filter, and the combustion air blower, the enclosure including an air inlet arranged to receive combustion air for the blower therethrough into the enclosure; and
  • a fuel heater supported within the enclosure in heat exchanging relationship with at least one of the supply and return lines in proximity to the pump and in heat exchanging relationship with air communicating between the air inlet of the enclosure and the combustion blower.

When the system is provided on a portable fuel fired heater as in the preferred embodiment, components of the system of the present invention typically include the following: 1. Burner and manifold compartment; 2. Two element electric air/oil warmer, 3. Auxiliary air warmer, 4. Concentric hose as a heat exchanger, and 5. Tank return oil well. According to the preferred embodiment, the operating features of the fuel oil supply system of the present invention are typically as follows:

1. The pump is switched on and runs constantly, recirculating fuel around the system, so that fuel under full pressure is always available at the solenoid valve on the nozzle branch line. A ‘main heat on’ command will cause the solenoid valve to open, and fuel flow from the nozzle to be ignited and the portable heater fan to come on and deliver hot air to the space.

2. This constantly recirculated fuel is used to convey heat throughout the whole system.

3. Ordinarily, there is only enough electrical power to run the portable heater burner with pump and combustion air blower during the ‘main heat on’ portion of the cycle, and the main fan—with only a small surplus available for electrical warming of fuel and air in the compartment.

4. During the ‘main heat off’ portion of the cycle, no fuel is being pumped through the nozzle at high pressure, which makes a larger surplus available for electrical warming of fuel and air in the compartment.

5. The electrical service in this representative case would be a nominal 15 amps, meaning a maximum of 12.5 amps in total that can be drawn from the service,

6. During the ‘main heat on’ portion of the cycle, when fuel is pumped at high pressure through the nozzle, this surplus would be at its minimum, about 4 amps.

7. During the ‘main heat off’ portion of the cycle, with the combustion blower still circulating air from the compartment up through the burner barrel and fuel recirculating throughout the system, but with the high pressure flow to the nozzle shut off, this surplus would be at its maximum, about 8 amps.

8. Since less heat from electrical warming is available during the ‘main heat on’ portion of the cycle, and in order to compensate, heated air is drawn into the compartment from the portable heater.

9. In both the ‘on’ and ‘off’ cases, air temperature in the compartment is held as near to 99 degC as possible, but not over the boiling point of water, and this warmed air is circulated by the combustion air blower up through the burner barrel and around the non-recirculating branch to the nozzle, keeping the fuel in that branch and the nozzle warmed, free of nozzle plugging ice crystals, and in optimum atomization and vaporization condition to assure ignition.

10. The minimum surplus electrical power, as in 6, is utilized to warm both the fuel flow through, and the air in, the compartment, with an electrical immersion heater placed in the return line of the pump, which is the inner line and less prone to heat loss to ambient.

11. The maximum surplus electrical power, as in 7, is utilized to warm both the fuel flow through and the air in the compartment, with an additional electrical immersion heater placed in the supply line of the pump.

12. Some heat will be imparted to the air in the compartment by the warmed fuel in the manifold under some conditions, and vice versa under other conditions. The electrical fuel warming immersion heater housings, are placed in the path of the air entering from the portable heater housing, which will be warm or cold depending on whether the portable heater is in the ‘on’ or ‘off’ mode. The housings are also in contact with each other, with some heat transfer taking place there from the return to the supply fuel lines. There are two major external areas of exposure that the fuelling system has where heat must be applied, and that is around the portion submerged in the tank, and the portion in the compartment exposed to ambient and to cold air entering during the ‘off’ portion of the cycle for the portable heater. The heat interchange is intended to be as flexible as possible to accommodate these outer requirements, and the previously named inner points of accumulation of ice and wax that reduce overall dependability and which can be removed by heat.

13. In order to get heat into and throughout the whole fuelling system, it is necessary to heat 100% of the oil being circulated, 85% of which is re-circulated back to the tank, which, if allowed to disperse throughout the tank would be lost to atmosphere because the tanks exposed surfaces would have a larger heat loss than the heat being returned and the tanks content would remain at ambient.

14. Because there is a relatively small amount of surplus electrical power available to increase and hold temperatures in the air in the compartment and in the fuel, it is necessary to reclaim rather than lose the heat imparted to the 85% re-circulated back to the tank.

15. This is accomplished by the function of the coaxial hoses of the safety fueler as a heat exchanger through the interface between the inner and warmer return line and the outer and colder supply line, and which is a major factor in very generally blending temperatures throughout the fuelling system.

16. By the return of oil in the partitioned volume in the tank, the partitioned volume holds the warmed return oil in the proximity of the supply inlet while allowing entrained bubbles to rise out of the return flow which in turn merges with the larger volume of the flow entering the supply inlet. The lower portion of the partitioned volume forming the well also provides a curb which will exclude from the flow, water settled at the bottom of the tank.

17. In the event that cold conditions are very severe, and presuming that a second 15 amp service can be provided, an auxiliary air heater may be utilized in the compartment.

18. In the event of initial startup under extreme cold conditions and equipment is cold soaked, the electric heaters only may be turned on and allowed to cycle on their temperature controls in order to pre-warm the compartment, burner barrel and fuel manifold including the pump to remove any existing icing in the fuelling system before attempting to place the system in recirculation and achieving fuel pressure for ignition. The system may then be left in the recirculation, or ‘standby’, mode for a period of time necessary to increase fuel temperatures such as to reliably achieve ignition.

19. In ongoing operation under extreme cold conditions, the system may be left in the recirculation or ‘standby’ mode during longer shutdowns such as overnight or over weekends, rather than completely shut down and cooled down, which will assure immediately reliable restart.

Other aspects of the present invention relating more particularly to diesel engine driven portable equipment stationed on site such as generator sets, contribute to overcoming fuel supply difficulties and failures which may occur due to marginal or inadequate suction of the integral oil feed pump when the oil source is altered from an integral trailer mounted tank to a ground mounted remote tank because this may add to the system the resistance of an anti-siphon valve installed at the remote tank by providing a booster pump in series with the integral oil feed pump.

According to this aspect of the present invention there is provided a fuel oil supply system in combination with a fuel consuming device for conducting fuel oil between a remote fuel container and the fuel consuming device in which the fuel consuming device comprises a fuel combustion area, a fuel metering device arranged for metering fuel to the fuel combustion area, and an integral feed pump having an inlet, a consumption outlet adapted to direct fuel to the fuel metering device, and a return outlet, the fuel oil supply system comprising:

a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device;

a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container;

an anti-siphon device supported in series with supply line in which the anti-siphon device comprises a valve member which is biased to a closed position and which is only arranged to be opened by a prescribed reduction in pressure in the supply line which is greater than a reduction in pressure in the supply line associated with activation of the integral pump; and

an auxiliary booster pump arranged for operation in series with the supply line such that the fuel metering device is unaffected by the auxiliary booster pump;

the auxiliary booster pump being further arranged such that a reduction in pressure in the supply line associated with activation of both the booster pump and the integral pump is greater than the prescribed reduction in pressure of the anti-siphon valve.

In a preferred embodiment there is provided a bypass line in parallel with the booster pump and a valve in series with the bypass line which is arranged to be opened in response to the booster pump being inactive and closed in response to the booster pump being active.

Various embodiments of the invention will now be described in conjunction with the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of the fuel oil supply system;

FIG. 2 is a cross sectional view of a first embodiment of the fuel lines;

FIGS. 3 and 4 are cross sectional view of alternative embodiments of the fuel lines;

FIG. 5 is a schematic representation of a first embodiment of the auxiliary booster pump; and

FIG. 6 is a schematic representation of a second embodiment of the auxiliary booster pump.

In the drawings like characters of reference indicate corresponding parts in the different figures.

DETAILED DESCRIPTION

Referring to the accompanying figures there is illustrated a fuel oil supply system 10 for use with a portable fuel consuming device 12. In the illustrated embodiment the device 12 comprises a portable fuel fired construction type heater, though the system 10 is applicable to any other fuel fired equipment such as diesel generators and the like.

The system is used with a bulk fuel container 14 which is typically a portable container such as a barrel of oil and the like which is supported remotely from and independently of the portable fuel consuming device 12. The container 14 is connected by suitable flexible safety hoses for conducting fuel oil therethrough from the container to the fuel consuming device, a distance for example of 25 feet. Although various configurations of the hoses are described in the following, in each instance the hoses generally comprise a supply line 16 having an inlet end 18 arranged for a connection to the remote fuel container and an outlet end 20 for connection to the fuel consuming device. A return line 22 of the hoses extends in proximity to the supply line along the length thereof from an inlet end 24 to an outlet end 26. The inlet end of the return line is adjacent to the outlet end of the supply line so as to be arranged for a connection to the device 12. The outlet end 26 of the return line is adjacent to the inlet end of the supply line so as to be arranged for connection to the remote fuel container.

In the illustrated embodiment, the portable heater 12 generally comprises a frame 28 supported for rolling movement on the ground on respective wheels. At the top end of the heater frame a housing of the portable heater defines a main heater duct 30 extending from an inlet end 32 at one end of the frame to an outlet end 34 at the opposing end of the frame. A heater fan 36 is located at the inlet end for directing air through the main heater duct across a heat exchanger 38 centrally located therein. The heat exchanger comprises a combustion chamber and exhaust chamber having an outlet 40 extending outwardly through the top end of the heater duct 30. The combustion chamber locates a burner 42 at the inlet end thereof adjacent to the outlet end of the heater duct 30.

The frame further supports a combustion air blower 44 for drawing surrounding air into the blower and out through a combustion air duct 46 having an outlet directed into the combustion chamber surrounding the burner 42.

A fuel pump 48 is integrally supported on the frame for pumping the fuel from the bulk container to the burner. More particularly, the fuel pump includes an inlet 50 in communication with the outlet of the supply line, a consumption outlet 52 in communication with a main fuel line 54 communicating pumped fuel to the burner, and a pressure regulation outlet 56 in communication with the inlet of the return line. An electric motor 58 drives the blower and the pump together under normal operation of the heater. A solenoid valve 60 is connected in series with the main fuel line 54 adjacent the consumption outlet of the pump which remains open under normal heating operation, but which is closed when the heater is not in operation. The main fuel line 54 is arranged to extend primarily through the combustion air duct 46 from the blower to the burner.

A fuel filter 62 is also provided in series with the supply line in proximity to the pump inlet.

The system 10 further provides an enclosure 64 on the heater for fully surrounding the filter 62, the fuel pump 48, the solenoid valve 60 and the blower 44 such that the entirety of the main fuel line 54 is located either within the enclosure or the combustion duct 46. The enclosure 64 includes an air inlet opening 66 arranged to receive combustion air into the enclosure for being drawn into the blower and directed to the burner through the blower duct. The air inlet opening defines a port in communication from the heater duct defined by the portable heater housing adjacent to the heat exchanger centrally located therein such that the air drawn into the enclosure is drawn from air heated in the heater duct under normal operation. This port communicating heated air into the enclosure typically provides the only source of fuel and air heating within the enclosure during the normal heating mode of the portable heater as described in further detail below with regard to operation of the system.

The system 10 further comprises a fuel heater for heating the fuel and/or the air within the enclosure. The fuel heater includes a first heating element 68 connected in series with the return line in proximity to the return outlet of the pump. The fuel heater also includes a second heating element 70 which is similarly connected in series with the supply line in proximity to the fuel filter 62 which is in turn in proximity to the inlet of the pump. Each of the first and second heating elements of the fuel heater comprises an electrical resistance heater coil arranged to be submerged within the fuel communicated through the respective fuel line.

The fuel heaters are positioned within the enclosure such that they are located within an air path of air being drawn by the blower through the enclosure from the air inlet to the blower such that the combustion air directed by the blower through the combustion duct can also be heated by the fuel heaters. In this instance the heated fuel lines resulting from the first and second fuel heaters define a suitable heat exchanger supported adjacent the air inlet opening 66 in heat exchanging relationship with the air entering therethrough as described in further detail below with regard to operation of the system.

In some embodiments, the system may also include an auxiliary air heater 72 supported within the enclosure in the form of an electrical resistance coil positioned in the path of incoming air at the air inlet 66 so as to be in heat exchanging relationship with the air as it is drawn into the enclosure through the inlet opening to the blower for use as combustion air also as described in further detail below with regard to operation of the system.

The fuel oil supply system further includes a manifold assembly 74 arranged to be inserted into the bulk container for communication of the supply and return lines with the container. A cap member 76 is mounted within an opening in the top wall of the container for supporting the manifold assembly extending downwardly therefrom into the container. Appropriate ports on the cap member communicate with the inlet of the supply line and the outlet of the return line respectively.

The manifold assembly 74 includes a baffle member 78 in the form of a main tubular body extending downwardly into the container substantially the full height of the container such that the bottom end of the baffle member is located in proximity to the bottom wall of the container and the baffle member defines a generally columnar shaped chamber within the bulk container which in turn defines a main partitioned volume extending vertically at a generally central location within the bulk container. The baffle member includes appropriate ports therethrough such that the fuel contained within the partitioned volume is substantially separated from but remains in fluid communication with a remaining volume 82 of the bulk container. The partitioned volume 80 typically comprises the minor portion of the overall volume such that the partitioned volume may be in the range of 10% or less of the total remaining volume 82 of the container for example.

A lower body 83 encloses the bottom end of the baffle member adjacent to the bottom wall of the bulk container such that the lower portion of the main partitioned volume comprises a lower partitioned volume 84 adjacent the bottom end of the container. More particularly, the lower body comprises a bottom wall 86 and a perimeter wall 88 extending upwardly therefrom about the full perimeter of the bottom wall to fully surround the lower partitioned volume and prevent communication of the volume with the remaining volume except through the open top end to the remainder of the main partitioned volume. The lower body thus defines a well receiving the lower partitioned volume of fuel therein which only communicates with the surrounding volume of fuel at a communicating location 90 which is spaced upwardly above the bottom end of the tank.

The manifold further includes an inlet tube 92 extending downwardly fro the cap member, essentially through the baffle member, to an inlet opening 94 at the bottom end of the inlet tube which is located adjacent the bottom of the baffle member and adjacent the bottom end of the container at an elevation which is below the communicating location 90 of the lower partitioned volume. The outlet of the inlet tube 92 is connected to the supply line at the cap member such that fuel drawn into the supply line from the container is drawn from the lower well defined by the lower body 82 which primarily comprises fuel in the main partitioned volume of the baffle member thereabove.

Any water which has settled out of the fuel adjacent the bottom end of the tank below the communicating location 90 of the lower partitioned volume is prevented from entering the well and thus prevented from entering the supply line. In addition to ports adjacent the bottom end of the baffle defining the communicating location of the lower partitioned volume, the baffle member also includes ports adjacent the top end such that air at the top end of the fuel container openly communicates with any air space at the top end of the partitioned volume.

The annular space extending through the baffle member surrounding the inlet tube which is primarily the main partitioned volume 80 is in communication with the return outlet at the cap member such that fuel from the return line which has been heated by the fuel heaters is directed downwardly through the annular space towards the inlet opening 94 at the bottom end thereof. The annular space is much larger in cross sectional area perpendicular to the flow direction than the inlet tube of the supply line or the return line such that flow through the annular space is much slower than the inlet tube or return line. This allows air entrained in the fuel oil to more readily rise against the return flow in the annular space where it is vented at the top end through a suitable air vent 96 instead of being drawn into the inlet tube of the supply line. While ports are provided for allowing some communication of fuel between the partitioned volume and the remaining surrounding volume, typically, the only flow between the two involves a small flow from the remaining volume into the partitioned volume to replace the fuel consumed by the device 12. The remaining portion of the fluid is mainly re-circulated through the supply and return lines to the fuel heaters and back to the partitioned volume such that the recirculation permits a small portion of fuel to be considerably heated relative to the remaining volume with much less energy input than heating all of the fuel.

An anti-siphon valve 98 is connected in series with the inlet tube 92 adjacent the top end thereof so as to be connected in series also with the supply line connected thereto. The anti-siphon valve is substantially identical to the valve described in U.S. Pat. No. 6,641,000, the disclosure of which is incorporated herein by reference. More particularly, the anti-siphon valve is a check valve permitting flow therethrough only in the supply direction from the bulk container to the device but which includes suitable biasing such that the valve is biased to the closed position. The biasing force exceeds the suction force imposed by gravity of the supply line draining to the exterior in the event of any line failure. The biasing force however is less than the suction force applied by the pump to the supply line such that activation of the pump causes the valve to be automatically opened, but the biasing closes the valve automatically when the pump ceases operation or in the event of a failure of the supply line. An auxiliary shut off valve 100 in the form of a manual valve is also provided in series with the inlet of the supply line at the cap member.

In the illustrated embodiment, the supply and return lines comprise coaxial lines in which the return line extends substantially concentrically through the supply line from the outlet end to the inlet end of the supply line along the full length thereof. In this instance where the fuel in the return line is primarily heated, the heated fuel is returned centrally through the coaxial tubes for preheating the surrounding supply line extending about the return line.

As shown in the accompanying figures, in other arrangements, the supply line and the return line may be located alongside and adjacent to one another with a surrounding tube forming a jacket to integrally join the tubes. Alternatively a more rigid casing of polymeric material may be extruded about the supply and return lines such that the supply and return lines are integrally joined as one common fuel conducting member. Generally in all instances, the supply line and the return line are supported in a heat exchanging relationship with one another along the full length thereof between the bulk container and the fuel consuming device.

The system 10 further comprises a controller 102 arranged to be supported on the heater in operative connection to the blower, the fuel pump, the air heater, the fuel heaters, and the solenoid valve 60. In this instance, the controller permits operation of the heater in various modes previously unavailable in conventional construction type heaters.

If the portable heater has been fully shut down for an extended period of time and is considered cold soaked, initially, the controller is operable in a pre-start up mode in which the fuel heaters are initially activated but the pump, the blower, the fuel heaters and the heating fan remain inactive while the solenoid valve 60 is closed. If each of the fuel heaters draw approximately 4 amps, the total draw in the pre-startup mode is only 8 amps. The air heater in this instance provides some preheating to the air within the enclosure for heating the fuel lines about the pump as well as heating the solenoid valve in the main fuel line to the burner.

When the auxiliary air heater is optionally provided, the air heater can be activated in place of the fuel heaters if it exceeds 4 amps of draw and only one 15 amp service is available on site. Alternatively, the auxiliary air heater can be activated in additional to the fuel heaters if there is more than one 15 amp service available or the draw of the air heater is approximately 4 amps or less.

Once a sufficient ambient temperature has been reached within the enclosure for a sufficient duration, the controller is operable in a second start-up mode, or alternatively a standby mode when the heater is cycled off from its normal heating mode. In this instance, the fuel heaters are activated and the fuel pump and blower may be started such that the heated fuel is circulated through the supply and return lines to heat the prescribed volume of fuel in the container, while air heated within the enclosure is drawn into the blower and through the combustion duct surrounding the main fuel line to the burner and the nozzle of the burner for thoroughly thawing and de-icing the main fuel line to the burner. The solenoid valve 60 remains closed so that no fuel is communicated through the consumption outlet of the pump. If provided, the auxiliary air heater would typically be inactive during the standby mode. The pump and blower typically only draw approximately 4 amps when the valve within the main fuel line to the burner remains closed such that even activating the two fuel heaters at 4 amps each maintains the cumulative draw of power to within 12.5 amps or less in the standby mode.

Once de-icing has occurred throughout the fuel system by the prestart-up mode and subsequent standby mode, subsequent activation in a main operating mode of the portable heater results in the solenoid valve 60 being opened to supply fuel under pressure to the burner while the pump and blower remain active such that the burner can be ignited and air drawn by the heating fan through the main heater duct is resultingly heated. Due to the diversion port from the heater duct to the air inlet opening of the enclosure, the fuel heaters (and the air heater if provided) can be turned off such that the only electrical draw is approximately 8 amps corresponding to the draw by the pump and blower when the valve 60 is opened and the main fuel line to the burner is pressurized in the normal operating mode of the portable heater.

A throttling valve 104 may be optionally positioned within the return line adjacent the fuel heater for adjusting the heating rate of the fuel through the heater. Under typical operation, more than twice the fuel is pumped through the return outlet than through the consumption outlet such that under typical operation approximately 85% of the pumped fuel may be returned while only 15% is directed to the burner for consumption for example.

In further embodiments, when the fuel consuming device has an integral pump which is insufficient to overcome the biasing force of the anti-siphon valve 98, an additional booster pump 106 can be connected with the supply line adjacent the outlet end of the supply line and the inlet end of the integral pump.

In a first embodiment according to FIG. 5, the booster pump 106 is connected in a primary line 108 in series with the supply line, while a secondary line 109 is mounted in parallel with the primary line and pump. A solenoid valve 110 is mounted in series with the secondary line so as to be connected in parallel with the booster pump. The secondary lines functions as a bypass line to bypass the booster pump. The valve 110 in series with the bypass line is arranged to be opened in response to the booster pump being inactive and closed in response to the booster pump being active. In addition a throttling valve 112 is mounted in series with the booster pump within the primary line. In this instance, the solenoid valve 110 can be initially closed on start-up with the throttling valve 112 opened and the booster pump activated together with the integral pump for boosting the flow through the supply line and through the primary line in series therewith to the inlet of the pump while closing the bypass line. In the event that the integral pump of the device 12 is sufficient to maintain flow once it has started, the solenoid valve 110 can be subsequently opened by shutting off the booster pump for stopping flow through the primary line and maintaining flow through the bypass line under operation of the integral pump of the device.

In an alternative arrangement according to FIG. 6, the inlet of the booster pump 106 is connected directly in series with the supply line but includes a branched outlet including a primary outlet 114 connected in series directly to the inlet of the integral pump of the device 12 and a secondary outlet 116 which communicates to the return line and bypasses the integral pump of the fuel consuming device. The secondary outlet 116 is smaller and throttled in relation to the primary outlet 114. A shutoff valve 118 in the form of a solenoid valve is also connected in series with the supply line at the inlet of the booster pump to permit shutting down in the event of a main pump failure or other reasons for ceasing operation of the booster pump and flow through the supply line.

In the instance of the fuel consuming device comprising a diesel generator for example, a fuel metering device meters the deliver of fuel to the combustion area and an integral feed pump, for example a vane pump having an inlet, a return outlet and a consumption outlet directs fuel oil to the fuel metering device. Connection of the booster pump in series with the inlet of the integral feed pump thus has no affect on the metering of fuel to the combustion area.

The Booster pump is not required in the application of the Safety Fueler for the remote fuelling of portable heaters which are normally equipped with pumps capable of overcoming considerable suction and resistance, more than imposed by this system. However, the fuel pumps and injectors commonly supplied integrally with diesel engines in portable equipment such as generator sets, which will be used as the model here, are usually quite limited in suction or lift capability, often to only the vertical distance from integral trailer mounted, as opposed to remote ground mounted, fuel tanks, up to the integral fuel pumps/injectors—representatively not more than 24 ins. plus an allowance of another 24 ins to a total of say 48 ins of suction or lift capability. In comparison, the suction required in remote fuelling must be sufficient to overcome the total of the resistance of the anti-siphon valve rated to full tank height, plus the lift from the Safety Fueler hose normally also run along the ground, and up to the integral fuel pumps/injectors of the trailer mounted engine—as much as 100 ins including some allowance for irregular ground.

The difference between the two lift requirements here is profound, and in such circumstances this difference would preclude integral pumps/injectors from holding, let alone achieving, operational prime.

However, in the field, due to failure to appreciate that anti-siphon valves must have a resistance to flow sufficient to prevent fuel escape from a filled tank due to siphoning should the line from the bottom of the tank and up and over the top and down to the ground be severed, many anti-siphon valves for tanks have been supplied or replaced with anti-siphon valves with weaker, and therefore hazardous with regard to accidental escape of fuel, resistance that reduces total lift required to what can be accommodated by integral fuel pumps/injectors. This difference is not visible in any fashion, especially with the anti-siphon valves inside the tank, and the test to check the anti-siphon is cumbersome and messy.

With this complete family of products, the booster pump has enough extra lift to overcome the full tank height rated anti-siphon valve supplied with the Safety Fueler, as well as to provide lift up to the integral fuel system of the engine, and additional pressure to extend the length of the Safety Fueler, such as to assure—without inspection or test of existing anti-siphon valves being required—safe and reliable fuelling with any conventional height of remote tank within reasonable distance from the generator set or other engine driven piece of equipment.

The manner in which the booster pump is integrated with the integral fuel pump/injectors is according to either one of the following two embodiments.

In the first instance, the integral fuel feed pump is connected on its inlet side to the outlet of a two-line booster pump, and have the outlet side of the integral fuel feed pump connect to the outlet of the booster pump. Because the pressure at the outlet side of the booster pump must always be adequate to lift the returned fuel to the height of the bulk tank in order to return it, and the integral feed pump should always be lower than the top of the tank, [a limit will be specified in the operating instructions for the system as to the maximum amount of ground height irregularity that can be tolerated between the tank and the generator set or other engine powered equipment] it will also be more than adequate to lift the fuel up to the height of the inlet of the integral fuel feed pump, and in this manner, supply fuel for operation. The recirculating flow rate of the booster pump must exceed the flow rate of the fuel feed pump, and a slight resistance to flow must be applied on the delivery side of the booster pump located between the connections to the integral fuel feeder pump in order to create a pressure difference between them to reinforce flow around the loop through the feed pump. Feed pumps are vane type pumps as opposed to positive displacement pumps, and variations of flow can occur at given rpm, but this can be tolerated without effecting fuel flow to the engine because fuel injection to the cylinders is fixed amounts by positive [piston pump] displacement. The booster pump may be either vane or positive [gear] displacement. The booster pump operation would be continual while the generator set or other engine driven equipment is in startup or in operation.

In the second instance there is provided a one-line booster pump inserted into the supply line of the integral fuel feed pump such as to reinforce suction to assist in providing enough lift to open the full tank rated anti-siphon valve in the tank immersed portion of the Safety Fueler and to raise the fuel up to the integral fuel feeder pump in order to establish initial prime for startup. The flow rate of the booster pump must exceed that of the integral fuel feeder pump such that a positive pressure will be created at the inlet of the feeder pump. There is a bypass around the booster pump with a solenoid valve in the bypass. The solenoid is normally open and closes when the booster pump is activated, such as to prevent this positive pressure from causing flow back to the inlet of the pump. When the booster pump is deactivated, the solenoid opens allowing unrestricted flow past the booster pump and directly to the integral fuel feeder pump. The operation of this one-line booster pump is intended to be intermittent, during startup only, in situations where the booster pump will establish prime against the resistance of the full tank rated anti-siphon valve, and, where the integral fuel feed pump is adequate to maintain prime once established and in operation. The booster pump can be held in operation during startup by pushbutton and then released when regular operation is achieved deactivating the booster pump and opening the bypass and providing direct access to the tank for the feed pump. Where prime cannot be maintained during operation by the integral fuel feed pump alone, the booster pump can be operated continually.

As described above, one aspect of the invention is a system of flexible hosing that will not allow escape of fuel in any manner if the hose is damaged or severed, and is particularly suitable for active sites such as construction where portable equipment such as heaters and generator sets can be provided with safe fuelling from a remote source up to 25′ away such as barrels or bulk tanks. The hose is inherently very reliable, has only one moving part, an anti-siphon valve. This product has already been field-proven, and is described in U.S. Pat. No. 6,641,000, the disclosure of which is incorporated herein by reference.

In addition, the invention relates to a combination of a remote fuelling safety hose, a tank de-icer heater and engine fuel supply lift booster. This provides a combination of an electric heater and pump and a safety fueler hose. The pump and heater are located at the portable equipment end of the system usually but not limited to 25′ away from remote fuel container. The fuel container requires minimal heat by creating a small pocket of warmed fuel around the fuel hose supply and return openings in the tank, and delivers warm fuel back to the equipment. This eliminates problems from always present water contamination of fuel, accumulating as ice at the bottom of containers, on strainers, filters, and anti-siphon valves and enables equipment such as generator sets to be operated remote from a bulk fuel source while providing: extended operation for equipment between fillings of the bulk tanks while eliminating fuel handling on the site; pressure boost up to integral fuel pumps; reliability without icing problems; safety by preventing fuel escape due to line damage from accident, vandalism or fuel theft; and provides the same operational advantages and fuel economies for portable diesel engines fuel pre-warmers and glow-plugs perform as standard equipment on mobile diesel engines.

An upgrading accessory package is available for idf oil heaters such that heaters equipped with it are capable of readily providing that most difficult of initial steps, start-up at sites that are completely frozen to outside temperature in extreme cold country and keep those sites in operation in extreme cold country. If a heater requires routine servicing and shuts down, it can be serviced without having to thaw it out first. The full package includes; the safety fueler hose with tank de-icer heater operating off of the heater fuel pump, plus heater filter and burner barrel heating in an enclosing housing at high enough heat that the filter and nozzle can be de-iced even at extreme low temperature conditions.

The GSA minus 30 or lower ratings that all other portable oil fired heaters now bear, are nominal only, applying only to the minimum allowable temperature exposure for individual components, with the whole heater untested for startup and operation at the rated temperature and, as is well known in extreme cold country, has little relevance to reliability which becomes problematical when units are cold soaked to ambient temperatures of minus 10 and below. With regard to cold country, in the whole of the North American Upper Mid-West, this ability to start and stay going in extreme conditions, provides the same degree of comfortable reliability with oil heaters as heaters with other fuels, plus the ease of moving around on site that only oil heaters can provide.

The invention may take the form of a pump normally located at the object item of equipment being fuelled, and an electric fuel heater on the return line from the pump, which is the inner and pressurized conduit, such that heated fuel is returned to the fuel container. This pump may either be the fuel pump integral to the object equipment such as with portable construction heaters, or it may be additional to that integral pump and in effect be promoting fuel to it such as with diesel driven portable generator sets.

The proportions, with a ‘two-line’ pump system employed on fuelling and having a supply and a return, are such that of the 100% of fuel volume drawn from the container and delivered to the object equipment, a smaller portion (representatively, 15-20%) is directly delivered to consumption by the object equipment or indirectly through delivery to the integral fuel pump of the object equipment, while a larger portion (representatively, 80-85%) is diverted back to the fuel container. The supply line inlet/return line outlet in the tank are configured in relation to each other such that the heated fuel is released from the outlet in the immediate vicinity of the inlet, in a manner and of a sizing affecting flow velocities such that air or foam entrained in the returning fuel will very substantially escape by rising away as opposed to being drawn back into the inlet, while the heated fuel will very substantially be drawn back into the inlet.

Lines dropping down into the container will be prevented from creating a siphoning out from the container and escape of fuel should these lines outside the container be punctured or severed, by either providing a siphoning check device, or, by providing vent openings into the line above the level of fuel in the container, which will also serve to discharge any accumulated foam back into the container, and an outside vent directly out of or above the container.

There may be a further provision in the system in the container to both; assure blending of the two flows to the hose inlet in the container, and, some degree of separation of water from that flow as the level in the tank approaches empty, in that separated water standing in the bottom of the tank will normally be the last intake into the system as fuel supply runs out causing engine stoppage or flame failure and shutdown which in turn could occasion re-start problems. By providing a curb at the bottom of the contained, either as an extended portion of the outside hose dropping into the tank, or as a permanent feature of the container, standing to a higher height than accumulations of water will occur or will be allowed to occur with monitoring, with the hose intake opening located below the height of the curb to assure mixing of the flows before entering the inlet, this last intake of water can be prevented.

The effect is that the smaller portion of fuel being drawn from the container to replace the fuel being consumed, which will tend to be at the same temperature as the ambient surrounding the container as opposed to being heated, will mix at the inlet with the larger heated portion being returned and drawn back into the inlet, such that both the fuel in the immediate volume around the outlet/inlet in the container, and the fuel being drawn through all the components of the fuelling system extending from the inlet in the container through all components upstream of the fuel heater including the strainer and anti-siphon device, and downstream of the heater, will be appreciably warmed above ambient, and that this is achieved by heating only the volume of fuel in the immediate proximity of the hose inlet and outlet, creating the same effect as heating the whole volume of the fuel container but with substantially less heat energy than that would require.

As well as the benefits attendant to heated fuel such as; greater efficiency of fuel usage, and easier startup under cold ambient conditions, a major benefit is that this warming throughout the fuelling system reduces or eliminates icing accumulation problems due to water contamination in the fuel, effectively always present in fuel due to handling and storage that does not protect against direct contamination, and/or due to condensation in fuel containers and/or the hygroscopic properties of the fuel.

Both diesel engines and burners of space heaters are capable of startup and reliable operation with fuel that has significant water contamination (representatively, 10%) provided the mix is heated.

Reduction of operational problems due to ice accumulations occurring due to both; separation, pooling, and reduction of temperature, and, impingement of water particles or ice crystals suspended in the fuel and impingement on surfaces at reduced temperature, the combination resulting in icing permeating the fuel system, will be achieved in some proportion to the increase of fuel temperature above ambient and that if the increase of fuel temperature in the immediate volume around the inlet/outlet in the container is to a temperature above freezing at 0 C, such that an ice thawing temperature is maintained throughout the fuelling system, the above process will remove accumulated ice from the fuelling container and system and eliminate operational problems therefrom.

If ice accumulations and water contamination resulting from thawing that are extensive, both diesel engines and burners of space heaters are capable of startup and reliable operation with fuel that has significant amounts of water contamination [representatively, 10%], provided the mix is heated [representatively, to within 10 deg C. of the freezing pt of 0 C for fuel oil ignition purposes and to above freezing for de-icing pursposes]. In any event, problems with obtaining and maintaining proper combustion will be reduced in some proportion to the heating of the water contaminated fuel.

The heating of fuel will also reduce or eliminate operational problems due to paraffin precipitation from oil fuels which tends to occur as temperature is reduced and which accumulates as a solid on such components as main fuel filters, fuel injectors and on nozzle filters, causing clogging and problems therefrom, including appreciably decreasing the service life of main fuel filters.

When the arrangement described above is used in combination with an integral fuel pump (such as with a diesel engine driven generator), the temperature rise of the heated fuel can be increased or decreased by throttling the return line with a valve and increasing or decreasing the rate if fuel flow while heating capacity remains fixed, while the integral pump and injectors remain drawing only the amount of fuel required for consumption.

Also in combination with an integral pump, the booster pump can be utilized to supplement the relatively weak ‘lift’ of integral fuel pumps which often provide lift only from also integral fuel tanks at or near the same level as the engines with both mounted on a raised skid or trailer, but inadequate to provide reliable lift from tanks or barrels at ground level which as well may be remote from the object equipment and situated at a lower level due to terrain. In such instances, the booster pump can provide lift to promote fuel up to integral pumps.

The heated fuel may also be diverted to an air heat exchanger in an enclosure around the object equipment, in order to provide general warmth for a compartment enclosing the object equipment, and more specifically for pre-heating of the combustion air drawn into the fuel consumption process which further assists ignition of the heated oil and increases efficiency of combustion. Alternatively, this air heater may be energized directly by sharing part of the electrical supply of the fuel heater as opposed to sharing part of the heated oil.

The hose within a hose configuration above provides several additional advantages when utilized as a component of the booster pump. Heat exchange occurs between the inner heated return line and the outer supply line such as to offset heat losses from the outer line to ambient such that the fuel supply to the object equipment is also heated and assured of warmed fuel right from initial startup without having to wait for the establishment of a heated immediately surrounding volume of fuel in the container around the inlet/outlet, and, overall heat loss from the hose[s] is much reduced compared to the conventional twin hoses for supply and return in that overall surface area is reduced and hottest hose surface area is not directly exposed to ambient.

With IDF oil portable heaters, the accessory package of technology is additional to conventional design for portable IDF oil units in that; the supply hose is utilized, with the electric fuel heater, but, because two-line pumps are conventional to IDF oil heaters, utilizes the integral pump of the portable IDF oil heater burner as the only pump for both the direct supply of fuel to the burner barrel and nozzle for combustion, and the re-circulating of heated oil out to and back from remote, integral or accompanying fuel containers. The package also includes the electrical version of the compartment/combustion air heater which is an optional addition to the as describes above.

Further additionally, the package provides these following features and advantages.

The technology is focused specifically on portable indirect oil fired heaters, which differ from the fuelling and firing of engines in that one electric motor drives both the integral pump and the combustion air blower, with the pump in addition to having supply and return lines to the fuel container also having a branch through the burner barrel to the nozzle where combustion takes place. There is a solenoid valve at the outlet of the pump to this branch. With conventional designs, during the ‘main heat-off’ cycle, this motor is stopped, the pump and the combustion air blower which it drives are also stopped, and the solenoid valve on the burner branch line is closed. Consequently, fuel circulation in this branch line to the burner also stops. The ‘main heat-off’ is also the ‘stopped’ condition of IDF oil heaters—as they would be supplied to sites before initial startup, as they would be during extended periods of non-use on sites, and during extended shutdowns due to service being required. Ice crystallization from water contamination will build up in the fuel lines when the heater is subjected to cooling down to ambient (‘cold-soaking’) during freezing conditions. While such crystallizations will contribute to building up on filters, etc., the occurrence of this in the burner branch line on initial startup, or initiation of the ‘main heat-on’ cycle after an extended shut-down as for a service requirement or fuel supply requirement will cause instant obstruction and plugging of the burner nozzle and failure of the burner to achieve ignition—a condition that fairly commonly occurs and persists until the nozzle section can be removed and thawed where warmth can be found.

It is a feature of the present invention that the conventional IDF oil heater ‘on’ and ‘off’ cycling as above is modified such that on initial startup or after an extended shutdown as for a service or fuel supply requirement, a ‘pre-startup’ procedure is provided before advancing to the ‘main heat on’ portion of the cycle, during which an electrical version of the air heater as above is energized in a compartment provided around the fuelling manifold and burner pump and combustion air blower provides a ‘prewarm stage 1’ such that there is a general warming and thawing of ice in fuel provided for those components for a period of time before initiating a ‘prewarm stage 2’ when additionally the fuel pump/combustion air blower motor is started while the solenoid valve on the burner branch fuel line remains closed and the fuel heater is switched on such that heated oil will now be circulated throughout the fuelling system with the benefits previously described while unheated air is drawn into the compartment from openings in the housing of the portable IDF oil heater, is heated by the compartment heater and drawn into the combustion air blower and forced through the burner barrel around the burner branch fuel line and nozzle such as to provide warming of that to prevent the formation of and to remove nozzle clogging water crystallization in that branch and to facilitate ignition by providing immediately available warmed fuel. When the ‘main heat-on’ portion of the cycle is subsequently initiated and ignition achieved, the main blower of the portable IDF oil heater will also begin moving main air flow through the portable IDF oil heater housing and the warming of air will take place before entering the compartment and the compartment heater will switched off during the ‘main heat-on’ portion of the cycle. Reduction of operational problems due to ice accumulations will be achieved in some proportion to the increase of fuel temperature above ambient in both the set of supply and return lines and the branch line to the burner, and that if the increase of fuel temperature is to above freezing at 0 C, such that an ice thawing temperature is maintained throughout the fuelling system, the above process will eliminate operational problems therefrom.

It is an important feature of this system that the combination of the electrical air heater and the electrical fuel heater placed in the same compartment, both having a fixed heating capacity, that the temperature rise of both the combustion air and the fuel as it is returned to the fuel container, can be adjusted up or down depending on the rise needed to exceed ambient temperature to prevent freezing or provide thawing, by increasing or deceasing the setting of the temperature control on the exit from the fuel heater. This, on increasing the set point, will cause the fuel heater which has surplus capacity, to cycle more frequently directly resulting in an increase of the fuel temperature rise, and because the housing of the fuel heater is located in the compartment, heat loss from that to compartment air will also indirectly result in an increase of combustion air temperature.

During the prewarm stage 2 portion of the startup procedure, the combustion air intake opening to the blower can be also be adjusted and the temperature rise of air flow past the burner branch line increased or decreased by altering the flow rate of the air while heating capacity remains fixed.

Once successful startup has been achieved and fuel temperatures throughout the system stabilized at above water freezing temperatures of 0 C, the heater and its fuelling will cycle reliably through ‘main heat on’ and ‘off’ with facilitated ignition and will be free from icing problems, and after extended off periods due to a service requirement can be serviced and restarted without complications due to becoming cold-soaked in the interval.

The combination of heated fuel and heated combustion air also provides a finer atomization from the nozzle or injector of the fuel because it is then less dense and viscous, while the increased temperature of fuel/air mix at the nozzle or injector increases vaporization of the fuel which is the state in which it is combusted. The effect of this is more reliable ignition, and higher efficiencies of fuel combustion and fuel heat realization for useful purposes are facilitated, with less complex and costly burners.

Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.

Claims

1. A fuel oil supply system in combination with a portable fuel fired heater for supplying fuel oil from a remote fuel container independent of the portable fuel fired heater wherein the portable fuel fired heater comprises:

a burner;

a combustion air blower arranged to deliver combustion air to the burner;

a pump having an inlet arranged for connection to a fuel supply line in communication with a remote fuel container, a return outlet arranged for connection to a return line in communication with the remote fuel container, and a consumption outlet in communication with a main fuel line between the pump and the burner so as to be arranged to deliver fuel to the burner; and

a combustion duct communicating from the blower to the burner and receiving the main fuel line extending therethrough;

wherein the fuel oil supply system comprises: a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device; a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container; an enclosure surrounding the pump and the combustion air blower, the enclosure including an air inlet arranged to receive combustion air for the blower therethrough into the enclosure and; a fuel heater supported within the enclosure in heat exchanging relationship with at least one of the supply and return lines in proximity to the pump.

2. The system according to claim 1 wherein the system further comprises a controller operatively connected to the portable fuel fired heater and the fuel oil supply system, the controller being adapted to operate in a standby mode in which the fuel heater is activated, a valve in series between the consumption outlet of the pump and the burner is closed, the pump is activated such that fuel oil is circulated between the remote fuel container and the fuel consuming device through the supply and return lines, and the blower is activated such that air heated within the enclosure by the fuel heater is drawn into the combustion duct for thawing the main fuel line extending therethrough.

3. The system according to claim 2 wherein the controller is further adapted to operate in a normal heating mode in which the pump is activated, the blower is activated, a valve in series between the consumption outlet of the pump and the burner is open such that the burner can be ignited, and the fuel heater is inactive.

4. The system according to claim 1 wherein the system further comprises a controller operatively connected to the portable fuel fired heater and the fuel oil supply system, the controller being adapted to operate in a pre-start-up mode in which the auxiliary fuel heater is active, the pump is inactive, and the blower is inactive.

5. The system according to claim 1 wherein the system further comprises an air heater supported within the enclosure in heat exchanging relationship with the air inlet and a controller operatively connected to the portable fuel fired heater and the fuel oil supply system, the controller being adapted to operate in a pre-start-up mode in which the fuel heater is inactive, the pump is inactive, the blower is inactive, and the auxiliary air heater is active.

6. The system according to claim 1 wherein the system further comprises a controller operatively connected to the portable fuel fired heater and the fuel oil supply system, the controller being adapted to operate in a standby mode, a normal heating mode and a pre-start-up mode;

wherein in the standby mode the controller is adapted such that the fuel heater is activated, a valve in series between the consumption outlet of the pump and the burner is closed, the pump is activated such that fuel oil is circulated between the remote fuel container and the fuel consuming device through the supply and return lines, and the blower is activated such that air heated within the enclosure by the fuel heater is drawn into the combustion duct for thawing the main fuel line extending therethrough;

wherein in the normal heating mode the controller is adapted such that the pump is activated, the blower is activated, a valve in series between the consumption outlet of the pump and the burner is open such that the burner can be ignited, and the fuel heater is inactive; and

wherein in the pre-start-up mode the controller is adapted such that the auxiliary fuel heater is active, the pump is inactive, and the blower is inactive; and

wherein the pump, the blower, and the fuel heater collectively are adapted to consume substantially equal to or less than 12.5 amps in each of the standby mode, the normal heating mode, and the pre-start-up mode.

7. The system according to claim 1 wherein the fuel heater includes a first heating element in communication with the return line in proximity to the pump.

8. The system according to claim 7 wherein the fuel heater further includes a second heating element in communication with the supply line in proximity to the pump.

9. The system according to claim 1 wherein the return line extends substantially concentrically through the supply line from the outlet end to the inlet end of the supply line.

10. The system according to claim 1 wherein the fuel heater includes a first heating element in communication with the return line in proximity to the pump and the system further comprises an adjustable throttling valve in series with the return line.

11. The system according to claim 1 wherein the supply line and the return line are joined in a heat exchanging relationship along respective lengths thereof between the respective inlet and outlet ends.

12. The system according to claim 1 wherein the system further comprises a baffle member arranged to be supported in the remote fuel container so as to define a partitioned volume in fluid communication with a remaining volume within the remote fuel container, the inlet end of the supply line and the outlet end of the return line being in fluid communication with the partitioned volume.

13. The system according to claim 12 wherein the baffle member is generally tubular in an upright orientation such that the partitioned volume is substantially columnar in shape, and the baffle member includes ports communicating therethrough adjacent opposing top and bottom ends.

14. The system according to claim 1 wherein the system further comprises a baffle member arranged to be supported in the remote fuel container so as to define a lower partitioned volume adjacent a bottom end of the remote fuel container, the lower partitioned volume being arranged to only communicate with a remaining volume within the remote fuel container at a fluid communicating location spaced upwardly from the bottom end of the remote fuel container, and the inlet end of the supply line being located within the lower partitioned volume below the fluid communicating location.

15. The system according to claim 1 wherein the pump is adapted to direct more than twice a volume of fuel through the return outlet than the consumption outlet.

16. The system according to claim 15 wherein the portable fuel fired heater further comprises a main heater duct receiving air to be heated therethrough, and a diversion port communicating from the heater duct to the enclosure about the pump and the blower.

17. The system according to claim 1 wherein the fuel heater is supported in heat exchanging relationship with air communicating between the air inlet of the enclosure and the combustion blower.

18. The system according to claim 1 wherein the system further comprises an auxiliary air heater supported within the enclosure separate from the fuel heater in heat exchanging relationship with the air inlet of the enclosure.

19. The system according to claim 1 wherein the system further comprises an anti-siphon device supported in series with supply line;

wherein the anti-siphon device comprises a valve member which is biased to a closed position and which is only arranged to be opened by a prescribed reduction in pressure in the supply line which is greater than a reduction in pressure in the supply line associated with activation of the integral pump;

wherein the system further comprises an auxiliary booster pump arranged for operation in series with the supply line; and

wherein a reduction in pressure in the supply line associated with activation of both the booster pump and the integral pump is greater than the prescribed reduction in pressure of the anti-siphon valve.

20. A fuel oil supply system for conducting fuel oil between a remote fuel container and a fuel consuming device including a pump having an inlet, a consumption outlet, and a return outlet, the fuel oil supply system comprising:

a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device;

a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container;

a fuel heater in communication with at least one of the supply and return lines; and

a baffle member arranged to be supported in the remote fuel container so as to define a partitioned volume in fluid communication with a remaining volume within the remote fuel container;

the inlet end of the supply line and the outlet end of the return line being in fluid communication with the partitioned volume.

21. A fuel oil supply system for conducting fuel oil between a remote fuel container and a fuel consuming device including a pump having an inlet, a consumption outlet, and a return outlet, the fuel oil supply system comprising:

a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device;

a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container;

a fuel heater in communication with at least one of the supply and return lines; and

a baffle member arranged to be supported in the remote fuel container so as to define a lower partitioned volume adjacent a bottom end of the remote fuel container;

the lower partitioned volume being arranged to only communicate with a remaining volume within the remote fuel container at a fluid communicating location spaced upwardly from the bottom end of the remote fuel container; and

the inlet end of the supply line being located within the lower partitioned volume below the fluid communicating location.

22. A fuel oil supply system in combination with a fuel consuming device for conducting fuel oil between a remote fuel container and the fuel consuming device in which the fuel consuming device comprises a fuel combustion area, a fuel metering device arranged for metering fuel to the fuel combustion area, and an integral feed pump having an inlet, a consumption outlet adapted to direct fuel to the fuel metering device, and a return outlet, the fuel oil supply system comprising:

a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device;

a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container;

an anti-siphon device supported in series with supply line in which the anti-siphon device comprises a valve member which is biased to a closed position and which is only arranged to be opened by a prescribed reduction in pressure in the supply line which is greater than a reduction in pressure in the supply line associated with activation of the integral pump; and

an auxiliary booster pump arranged for operation in series with the supply line such that the fuel metering device is unaffected by the auxiliary booster pump;

the auxiliary booster pump being further arranged such that a reduction in pressure in the supply line associated with activation of both the booster pump and the integral pump is greater than the prescribed reduction in pressure of the anti-siphon valve.

23. The system according to claim 22 wherein there is provided a bypass line in parallel with the booster pump and a valve in series with the bypass line which is arranged to be opened in response to the booster pump being inactive and closed in response to the booster pump being active.

24. A fuel oil supply system in combination with a portable fuel fired heater for supplying fuel oil from a remote fuel container independent of the portable fuel fired heater wherein the portable fuel fired heater comprises:

a burner;

a combustion air blower arranged to deliver combustion air to the burner;

a pump having an inlet arranged for connection to a fuel supply line in communication with a remote fuel container, a return outlet arranged for connection to a return line in communication with the remote fuel container, and a consumption outlet in communication with a main fuel line between the pump and the burner so as to be arranged to deliver fuel to the burner;

a fuel filter in series with the inlet of the pump; and

a combustion duct communicating from the blower to the burner and receiving the main fuel line extending therethrough;

wherein the fuel oil supply system comprises: a supply line having an inlet end arranged for connection to the remote fuel container and an outlet end arranged for connection to the pump of the fuel consuming device; a return line extending from an inlet end adjacent to the outlet end of the supply line and arranged for connection to the return outlet of the pump to an outlet end adjacent to the inlet end of the supply line and arranged for connection to the remote fuel container; the supply line and the return line being joined in a heat exchanging relationship along respective lengths thereof between the respective inlet and outlet ends; a baffle member arranged to be supported in the remote fuel container so as to define a partitioned volume in fluid communication with a remaining volume within the remote fuel container; the inlet end of the supply line and the outlet end of the return line being in fluid communication with the partitioned volume; an enclosure surrounding the pump, the fuel filter, and the combustion air blower, the enclosure including an air inlet arranged to receive combustion air for the blower therethrough into the enclosure; and a fuel heater supported within the enclosure in heat exchanging relationship with at least one of the supply and return lines in proximity to the pump and in heat exchanging relationship with air communicating between the air inlet of the enclosure and the combustion blower.