Abstract: An oven may include inner oven walls defining a cavity. The oven may further include a heating element configured to heat air in the oven. The oven may further include a fan positioned between the rear of the oven and the heating element. The fan may be configured to: draw air from the front of the oven to the rear of the oven; blow the drawn air over the heating element to produce heated air; and distribute the heated air within the oven.

Abstract: An analytical device has an oven arrangement (1) with an oven (2), an insulation system, a ventilation system and a housing. The ventilation system has a first convection system that uses natural convection, arranged to keep the housing cool, as well as a second convection system that uses forced convection, arranged to reduce the temperature in the oven (2). In particular, the analytical device is a component of a Karl Fischer titration instrument.

Abstract: A grain dying system for a grain bin that includes a heating unit arranged in a proximity of the grain bin and ducting connected at one end to the heating unit and another end to a grain drying adaptor. The grain drying adaptor is connected at one end to the ducting and at another end to a fain unit of an aeration system for the grain bin. The fan unit is attached to the grain drying adaptor. The grain drying adaptor is configured to introduce a blend of heated air from the heating unit and ambient air from outside the grain drying adaptor into the aeration system of the grain bin.

Abstract: A cooking appliance including an interior, a fan mechanism having at least one fan wheel in the interior, at least one first flow directing member for subdividing the interior into a pressure chamber that houses the fan wheel and a cooking chamber, in which the first flow directing member includes at least one suction port for sucking atmosphere from the cooking chamber into the pressure chamber when the fan wheel is in operation and at least one blow-off port for blowing atmosphere from the pressure chamber into the cooking chamber when the fan wheel is in operation; and at least one second flow directing member that is included with the fan mechanism in the area of the suction port of the first flow directing member in order to improve the flow from the cooking chamber into the pressure chamber by forcing an axial main flow H in the suction zone of the fan mechanism, where the second flow directing member performs a nozzle function, extends from the fan mechanism into the cooking chamber, and overlaps the e

Abstract: In one aspect, an oven is provided and includes a drum oriented with a vertical axis and a motor for rotating the drum about the axis, a conveyor belt having a length helically surrounding the drum, and having an infeed end and outlet end, a chamber defined by walls surrounding the drum and the length of the conveyor belt, and a plenum within the chamber and being curved substantially concentrically with the drum. The plenum forms a substantially closed air pathway having an inlet at one end and an outlet at an opposite end passing air into the chamber. The oven also includes a fan arranged to circulate air within the chamber and force air into the plenum inlet, through the plenum and out of the plenum outlet, and a heat exchanger arranged in the plenum.

Abstract: The invention relates to a process for manufacturing cement clinker in a plant having a cyclone preheater, a precalcination reactor, a rotary furnace and a clinker cooler. In the process, the flue gases from the furnace are conducted to the precalcination reactor, or even to the cyclone preheater. According to the invention, the precalcination reactor is fed with an oxygen-rich gas, the nitrogen content of which is less than 30%, constituting the sole oxygen source for said reactor, and a portion leaving the cyclone preheater is recycled into the plant so as to obtain a suitable flux necessary for suspending matter in said preheater, while the other portion, rich in carbon dioxide, is adapted for the purpose of a treatment for limiting the amount of carbon dioxide discharged into the atmosphere, such as particularly sequestration.

Abstract: An oven for use in an aircraft is disclosed, including a preparation space. A fan and a heater are located behind a separating wall. The separating wall has at least one of the following devices for enhancing the uniformity of air flow: —a throat around a central air intake opening in the separating wall—the separating wall provided with end edges which run close to the side walls of the preparation space and which are curved or bent towards the preparation space—flow guides extending along an edge of the separating wall and directed away from the preparation space.

Abstract: An oven apparatus 24 having a modular construction for curing paint on the surface of a vehicle body 26 using radiant and convection heat. The oven apparatus 24 includes a plurality of oven modules 30. Each oven module 30 includes a pair of convection return air assemblies 128 for removing exhaust gases from the oven interior 98 and a pair of radiant heating tubes 100 for heating the vehicle body. Each of the convection return air assemblies 128 has a reflective outer surface 94 for reflecting radiant heat from the radiant heating tubes 100 at the vehicle body 26.

Abstract: Heat recovery devices and methods for carbon baking furnaces are presented in which at least a portion of the waste heat from the cooling section is recycled through the furnace, which not only reduces the amount of natural gas required, but also increases the oxygen content in the furnace thereby reducing undesirable pitch build-up.

Abstract: A multizone convection furnace is provided in which gas from a cooling chamber of the furnace is directed into one or more heat zones of the furnace for the purpose of providing a specified thermal profile. The gas introduced from the cooling chamber into the one or more heat zones is of the same type of gas present in the heat zones, and typically is nitrogen. In a preferred embodiment, the convection furnaces comprises a heating chamber composed of a plurality of adjacent heat zones and a cooling chamber at the exit end of the heating chamber. A conveyer extends through the furnace for movement of a product through the heat zones and cooling chamber of the furnace. The cooling chamber is coupled to one or more of the heat zones such that cooled gas from the cooling chamber can be introduced into selected heat zones. In one version, a cooled gas path is provided to all of the heat zones and cooled gas is introduced into intended zones by opening associated valves.

Abstract: The invention relates to a method for the heat treatment of workpieces in a heat treatment furnace, wherein the treatment atmosphere in the heat treatment furnace is circulated. According to the invention, a propellant is injected into the heat treatment furnace in such a manner that the treatment atmosphere is essentially circulated by the injected propellant.

Abstract: Apparatus for batch processing source material into charcoal in a battery of kilns, each of which use forced convection of process gases through the source material to shorten the process cycle time, and all of which use an external combustor to burn the process waste gases from each kiln to provide the primary source of applied energy for the process.

Abstract: In a system for thermally processing materials, at least one slot eductor is disposed in a wall or roof surface of the furnace chamber to provide circulation of gas within the furnace chamber.

Abstract: Disclosed is a convection oven capable of producing a “true” convection cooking environment with a single gas burner disposed underneath the oven bottom in a combustion box. A fan compartment is disposed substantially at the center of the back wall, and defined by a baffle plate with a central fan inlet, a plurality of rearward-extending flanges, and a portion of the oven back wall. A centrifugal fan is disposed within the fan compartment. A flue spout is disposed between the oven cavity and the fan compartment and is adapted to join the combustion box and the oven cavity in fluid communication. Thus the centrifugal fan, located substantially centrally within the fan compartment will draw hot air and flue products upward from the combustion box, through the flue spout, through the central fan inlet, and blow the hot air and flue products into the oven cavity through peripheral fan outlets formed in the fan compartment.

Abstract: A temperature changing apparatus including a chamber defining a cavity is configured to receive a food product therein. A radially exhausting fan disposed in the cavity circulates air in the cavity over the food product. An air deflector disrupts the air radially exhausted from the fan.

Abstract: A method and an apparatus for the thermal treatment of metallic workpieces with which gas quenching can be obtained that is low in distortion, even for workpieces with an undulating shape or workpieces that are projectingly stackable are provided. In accordance with the method, after being heated the workpieces are cooled in a quenching chamber with a quenching gas, whereby the quenching gas is intentionally caused to flow around the workpieces by means of guide channels that have a closed lateral surface and that enclose the workpieces along the direction of flow of the quenching gas. The apparatus comprises a quenching chamber in which the workpieces can be cooled with a quenching gas, and wherein guide channels are provided to ensure that the quenching gas flows around the workpieces, the guide channels having a closed lateral surface and enclosing the workpieces along the direction of flow of the quenching gas.

Abstract: The present invention provides a system and method for binder removal and sintering of materials such as ceramic materials and products, LTCC intervals, solid oxide fuel cells and powder metals. A combination of microwave and convection/radiation heating is employed for binder removal and sintering. Preferably, the microwave heating is accomplished using a variable or multi-frequency microwave source. A gas atmosphere is provided in the furnace chamber by one or more eductors which produces a high volume gas circulation in the furnace chamber to achieve a highly uniform gas environment and temperature. The process in accordance with the invention controls the heating cycle, the heat sources and thermal profile depending upon the composition of the particular material being processed. The thermal processing can be accomplished in a batch furnace in which a product is loaded for processing and unloaded after processing.

Abstract: A gas-cooled single-chamber type heat-treating furnace T in which cooling gas vents 9A and 9B opened and closed by doors 11A and 11B are provided on each of mutually opposed walls of an inner chamber 5 forming a processing room and cooling gas is circulated by opening the cooling gas vents 9A and 9B during gas cooling, wherein the cooling gas vents 9A and 9B of the inner chamber 5 are provided with lattice-shaped flow uniforming members 19 made of heat-resisting materials.

Abstract: Reflow solder oven gas management system introduces an inert gas into and removes contaminated gas from a reflow oven tunnel (42) at predetermined points (6, 8) to influence the oven tunnel gas flow and to dilute and expel excess oxygen. The contaminated gas is ducted to a flux separation system (34) to be cleaned, for example remove flux vapors, and returned in part to the tunnel (42) for recirculation and with the remainder routed to end baffle boxes (54) for tunnel end pressurization and exhaust. The system has sufficient pressure to supply end baffle boxes (54) with clean gas to create a gas barrier to effectively seal off the tunnel ends from air infiltration or migration into the tunnel making the system insensitive to external pressure and/or temperature variations. The invention also includes alternative embodiments, low flow oxygen bleed valves (72) to maintain low oxygen content in the oven process tunnel.

Abstract: Disclosed is a convection oven capable of producing a “true” convection cooking environment with a single gas burner disposed underneath the oven bottom in a combustion box. A fan compartment is disposed substantially at the center of the back wall, and defined by a baffle plate with a central fan inlet, a plurality of rearward-extending flanges, and a portion of the oven back wall. A centrifugal fan is disposed within the fan compartment. A flue spout is disposed between the oven cavity and the fan compartment and is adapted to join the combustion box and the oven cavity in fluid communication. Thus the centrifugal fan, located substantially centrally within the fan compartment will draw hot air and flue products upward from the combustion box, through the flue spout, through the central fan inlet, and blow the hot air and flue products into the oven cavity through peripheral fan outlets formed in the fan compartment.

Abstract: An automatic oven cooks or bakes a food product over a timed period of time during which a burner delivers heat to the oven cavity. Thermocouple sensors in the cavity control a modulator which regulates the amount of gas flowing to the burner to maintain a uniform temperature in the oven. A conveyor carries the food product in order to time the baking period.

Abstract: This invention is directed to a process for recovering helium. The process includes a) passing a first gas containing helium to an eductor to produce a second gas; b) passing the second gas through a heat exchanger to produce a third gas; and c) recovering the third gas into the eductor to combine with the first gas.

Abstract: A combustion apparatus and process for improved flue gas recirculation wherein the recirculation line penetrates into an exhaust duct, such as the exhaust stack for capturing and directing a portion of said flue gas through the recirculation line which is connected to an air fan inlet which provides induction of the flue gas into the combustion unit. The portion of the recirculation line that extends into the exhaust stack is preferably aerodynamically configured to capture a portion of a flue gas stream without detrimental impedance of the gas flow.

Abstract: Disclosed is a convection oven capable of producing a “true” convection cooking environment with a single gas burner disposed underneath the oven bottom in a combustion box. A fan compartment is disposed substantially at the center of the back wall, and defined by a baffle plate with a central fan inlet, a plurality of rearward-extending flanges, and a portion of the oven back wall. A centrifugal fan is disposed within the fan compartment. A flue spout is disposed between the oven cavity and the fan compartment and is adapted to join the combustion box and the oven cavity in fluid communication. Thus the centrifugal fan, located substantially centrally within the fan compartment will draw hot air and flue products upward from the combustion box, through the flue spout, through the central fan inlet, and blow the hot air and flue products into the oven cavity through peripheral fan outlets formed in the fan compartment.

Abstract: A forced air heating system has a heat regulating unit assembled therewith, the heating system comprising a furnace having fuel burner and a flue pipe for outlet gases. The heat regulating unit has a metal flue conduit with a flue gas inlet and a flue gas outlet connected to the flue pipe in proximity to the furnace to form a portion of the flue pipe. An elongated casing surrounds the flue conduit and defines with the flue an annulus in which a series of equispaced metal fins extend radially from the flue conduit to the casing to define chambers containing a heat-absorbing material such as metal wool. The heat regulating unit functions as a heat-sink to absorb heat from the hot fuel and a heat source gases for return to the furnace by conduction and convection.

Abstract: A conveyor oven has a modulating gas valve which raises and lowers the thermal output of a burner that heats the oven. A bypass line passes a minimum amount of gas to prevent the burner from completely shutting down during periods while the oven remains above a threshold demand for more heat. Electrical isolation is provided between temperature controlling devices to prevent an electrical feed back which might otherwise prevent a complete shut down of the oven during hazardous conditions.

Abstract: Apparatus for heat treating a heat treatable material including a housing having an upper opening for receiving a heat treatable material at a first temperature, a lower opening, and a chamber therebetween for heating the heat treatable material to a second temperature higher than the first temperature as the heat treatable material moves through the chamber from the upper to the lower opening. A gas supply assembly is operatively engaged to the housing at the lower opening, and includes a source of gas, a gas delivery assembly for delivering the gas through a plurality of pathways into the housing in countercurrent flow to movement of the heat treatable material, whereby the heat treatable material passes through the lower opening at the second temperature, and a control assembly for controlling conditions within the chamber to enable the heat treatable material to reach the second temperature and pass through the lower opening at the second temperature as a heated material.

Abstract: An apparatus including a housing defining a heating process chamber. The housing has an opening communicating the process chamber to the ambient atmosphere. A burner is included that fires into a combustion chamber to heat gas. Also included is a collector structure located outside the opening. The collector structure is configured to collect air and exfiltrated gas from an outside area adjacent to the opening. The apparatus also includes a duct structure communicating the collector structure with the burner so as to supply the collected air and exfiltrated gas to the burner and thereby to supply combustion oxidant to the burner.

Abstract: A method for heat-treating metallic workpieces, in which a flow of cooling gas is generated in a vacuum furnace by a fan in order to quench the workpieces, with the fan being driven by a rotary current motor that is operated with a predetermined supply voltage above a minimum pressure in the vacuum furnace which is determined with regard to the motor power of the rotary current motor. In order to additionally develop this method such that a simple and inexpensive improvement of the quenching effect is achieved, the fan is started at a pressure in the vacuum furnace which is lower than the minimum pressure, with the rotary current motor being operated with a second, lower supply voltage until the minimum pressure in the vacuum furnace is reached.

Abstract: The heat exchanger is particularly for ovens for food cooking comprising a radial fan, and is associated with a burner supplied by a blower. The heat exchanger has a first part of pipe into which the combustion gases are made to flow, which makes an almost-complete circuit of the radial fan before bifurcating into at least two pipes which extend around the radial fan.

Abstract: A convection oven with a filtration system for recirculated convection gas. The oven includes an interior chamber, a product support in the interior chamber and a blower in fluid communication with at least one duct (preferably a plurality) for circulating air into the interior chamber. The duct has a plurality of orifices positioned to direct temperature controlled gas toward the product support. At least one perforated filter plate with a plurality of bends is disposed within the interior chamber separating the interior chamber into a cooking chamber and an air return chamber. In leu of the filter plate the filtration system includes a plurality of louvers disposed in the interior chamber separating the interior chamber into a cooking chamber and an air return chamber, the louvers being downwardly inclined toward the cooking chamber and positioned such that the temperature controlled gas passes through the louvers before returning to the blower for recirculation into the air delivery duct.

Abstract: A forced convective track oven comprises a track conveyor including first and second circular spirals, the first circular spiral for conveying bakery trays and dough products upwardly and the second circular spiral portion for conveying bakery trays and dough products downwardly, thereby minimizing the number of changes of direction of the bakery trays as they travel along the track conveyor. A plurality of burners discharge heated air through discharge tubes and discharge nozzles into engagement with bakery trays carried by the track conveyor. First and second oval spirals may be used in lieu of the circular spirals when the track oven is used in a reduced ceiling height environment.

Abstract: A thermal treating apparatus and process providing convection thermal transfer for elevated processing temperatures and chemical treatment. A recirculation plenum for passage of spent treatment fluid from and fresh treatment fluid to a treatment chamber may contain a thermal control source, a chemical control source, and a blower to provide predetermined programmable temperatures and chemical environments to articles in the treatment chamber. Decreasing cross sectional areas along the length of the treatment chamber cause introduction of fresh treatment fluid at different locations along the length of the treatment chamber to achieve desired uniform thermal and chemical treatment of articles along the length of the treatment chamber.

Abstract: A method and apparatus for efficiently preheating glass batch utilizing waste gas from a glass melting furnace is provided. In a method and apparatus for preheating glass batch utilizing hot waste gas discharged from a glass melting furnace before glass batch is inputted thereto, a heat exchanger 30A for heating heat medium gas located in a waste gas flue 12A and a glass batch preheater 20A located on the upstream side of a batch input port 11A are communicated by means of an inline duct 31A and an outline duct 32A to form a heat medium gas circulating circuit. Clean gas having heat radiation intensity in the infrared ray wavelength range such as carbon dioxide or water vapor is enclosed in the circuit as the heat medium and is forced to endlessly circulate and go round in the circuit by a blower 33A located in the outline duct thereby to preheat glass batch and, at the same time, to cool hot waste gas to appropriate temperature.

Abstract: The present invention relates to a gas recirculating tubular heating equipment which improves the heat transfer performance, reduces a heat transfer area to approximately 1/2 or under of that of a prior art and is not limited to a certain type of available fuel. This equipment comprises: a furnace 1 having a plurality of tubes 19; heating chambers 2 provided with heat sources 3A and 3B for heating a recirculating gas current outside the furnace; and an out-of-furnace circulating path 4 for taking out a part of the recirculating gas current passing through the inside of the furnace 18 to the outside of the furnace and flowing it back from another position to the inside of the furnace 18.

Abstract: Furnace for processes and treatments in a sub-stoichiometric atmosphere, includes a combustion chamber (1) provided with a fuel-feeding mechanism, feeding mechanism (3) for combustion promoter and an extraction mechanism (4) for the gases produced in the interior of the chamber (1). The feeding mechanism (3) for combustion promoter and the extraction mechanism (4) for the gases are connected, in an alternating way with suitable selection mechanisms (203, 213, 104, 114), to the furnace through at least one device (2) connected by a suitable mechanism (402) to an open port (121) on the combustion chamber (1) of the furnace. The device achieves post-combustion (102) of the gases, heat exchange and heat storage (112).

Abstract: Disclosed is a paint drying furnace for baking and drying paint films on painted objects following a painting process. The furnace of the invention has an interior combustion type heating device arranged on fresh air passages upstream of points of connection to furnace interior circulating gas passages for heating passing fresh air. The combustion type heating device is a direct heating type, combustion type heating device for burning a fuel directly in an atmosphere of passing fresh air to be heated.

Abstract: The present invention involves a method and a device for the heat treatment of workpieces, which are heated with radiant heat generated through the combustion of gaseous fuel. Some of the workpieces are subjected to a carburisation atmosphere formed by a heated mixture of hydrocarbon containing gas and carbon dioxide, where the carbon dioxide has been separated from the exhaust gas of the gaseous fuel combustion. Other workpieces may be subjected to a nitrocarburisation atmosphere formed by a mixture of ammonia and the exhaust gas remaining after the carbon dioxide has been separated. By recycling some of the products of the combustion process, the present invention improves the efficiency of the carburisation process while reducing pollutant emissions.

Abstract: A furnace for thermally processing product includes one or more eductors. The eductor provides for increased circulation of atmosphere within the furnace for heat transfer or outgassing purposes. The eductor may be used to introduce clean gas to a product which outgasses volatiles to enhance the outgassing process by lowering the partial pressure of the volatile across the product as it is being heated. The eductor is also used to enhance heating or cooling of a product. Additionally, the eductor may be used to reduce or eliminate air stagnation areas within the furnace. The eductor may be located entirely within the furnace to recirculate the atmosphere of the furnace. Alternatively, the eductor may be located outside the furnace housing such that the eductor entrains gas from ports attached to the furnace and then reintroduces the gas into the furnace after the gas is cleaned, heated or cooled.

Abstract: A convection oven having an insulated oven chamber bounded by a front access door, a floor, a ceiling, two side walls, and a rear wall. An inlet air passageway, which includes a heating element, delivers heated air to the oven chamber, and an exhaust passageway exhausts air from the oven chamber. A baffle plate spaced from the rear wall divides the oven chamber into a blower compartment and a baking compartment, which are connected by a return air opening in the baffle plate and at least one peripheral opening outwards of the return air opening. A blower fan in the blower compartment draws heated air into the oven chamber, mixes the heated air with air already inside the even chamber, circulates the mixed air throughout the oven chamber, and expels air through the exhaust passageway. To alleviate problems caused by high and low pressure zones created in diagonally opposing corners of the blower compartment by rotation of the blower fan, two pairs of diverter plates are disposed around the blower fan.

Abstract: An infrared ray emitter with catalytic burner including a box having an opening covered by a catalytic structure and wherein a supply of combustion gas is applied adjacent the catalytic structure and a supply of recirculating gas is introduced into the box by a fan driven by a motor which extends exteriorly from a furnace in which the emitter is mounted. Brackets are provided to mount the box within a furnace in such a manner that the emitter may be angularly adjusted with respect to the support brackets.

Abstract: A gaseous fuel burner assembly for heating a space particularly an oven of a domestic cooking appliance comprises a gaseous fuel burner separated from the space by a baffle plate, and, also separated from the space by the baffle plate, a fan for withdrawing air from the space via an aperture or apertures in the plate and returning that air to the space via an exit or exits adjacent the edge of the plate, the or each aperture being so located that, during its passage from the aperture or apertures to the exit or exits, the air passes close to the burner. The fan may also draw in air from a plenum chamber behind the oven. The burner may be of the duplex variety and may have two independently controllable burner heads.

Abstract: An improved cooling arrangement is disclosed for an industrial heat treat furnace. The furnace includes a closed end cylindrical heat treat chamber in which a plenum plate is suspended adjacent the rear end thereof. The plenum plate has a central underpressure opening and a fan between the rearward end of the furnace and the plate develops a wind mass which circulates into the furnace chamber and is drawn back into the fan through the plates central underpressure opening. Between the plenum plate and the furnace rearward end is positioned a first fixed fan diffuser followed by a second fixed fan diffuser. The first fan diffuser permits wind mass flow therethrough when the fan is rotated in a first direction but not in a second direction and similarly the second fan diffuser permits wind mass flow therethrough when the fan is rotated in a second direction but not in a first direction.

Abstract: It is an object of the present invention to provide a vertical heat treatment apparatus having a heat insulator, which has sufficient heat insulation, heat retention and high load pressure bearing properties to cope with increased size dimensions and number of layers of wafer workpieces and can be particularly advantageously used as a semiconductor and TFT substrate heat treatment apparatus. The apparatus features the use of a heat insulator casing 40 supporting a substrate holder 3 on its top and receiving a heat insulator 50 having numerous inner microspaces in its lower space, and defining a substrate holder or boat insulator receiving space A and a heat insulator receiving space B such that these spaces are hermetically sealed with respect to each other by the heat insulator casing.

Abstract: An impeller for a high-temperature gas blower suitable for a floating conveyor furnace, having vanes each formed of a dispersion-strengthened alloy which includes as a disperse or internal phase 0.1-2.0% by weight of finely divided particles of an oxide of a high melting-point metal, such as Y.sub.2 O.sub.3, Ce.sub.2 O.sub.3, ZrO.sub.2, Al.sub.2 O.sub.3 and Gd.sub.2 O.sub.3, preferably dispersed in an austenite matrix or external phase of Cr, Fe, Al, Ti and Ni. A gas blower having such impeller, and a furnace using such gas blower are also disclosed.

Abstract: An improved cooling arrangement is disclosed for an industrial heat treat furnace. The furnace includes a closed end cylindrical heat treat chamber in which a plenum plate is suspended adjacent the rear end thereof. The plenum plate has a central underpressure opening and a fan between the rearward end of the furnace and the plate develops a wind mass which circulates into the furnace chamber and is drawn back into the fan through the plate central underpressure opening. Between the plenum plate and the furnace rearward end is positioned a first fixed fan diffuser followed by a second fixed fan diffuser. The first fan diffuser permits wind mass flow therethrough when the fan is rotated in a first direction but not in a second direction and similarly the second fan diffuser permits wind mass flow therethrough when the fan is rotated in a second direction but not in a first direction.

Abstract: The invention discloses a simply designed oven which uses forced air convection as a heating mechanism. One or more drums can be installed in the oven over a catch basin of sufficient volume to include the contents of at least one drum. A gear or similar pump is provided to agitate the contents, as well as to perform the pump-out feature. An inert gas blanketing system is provided for each drum so that additional inert gas is supplied to replace the contents being pumped out of the drum while excess vapors created from the warming process, which could ignite if placed adjacent an ignition source, can be piped to a safe place remote from the oven interior.

Abstract: An impeller for a high-temperature gas blower suitable for a floating conveyor furnace, having vanes each formed of a dispersion-strengthened alloy which includes as a disperse or internal phase 0.1-2.0% by weight of finely divided particles of an oxide of a high melting-point metal, such as Y.sub.2 O.sub.3, Ce.sub.2 O.sub.3, ZrO.sub.2, Al.sub.2 O.sub.3 and Cd.sub.2 O.sub.3, preferably dispersed in an austenite matrix or external phase of Cr, Fe, Al, Ti and Ni. A gas blower having such impeller, and a furnace using such gas blower are also disclosed.

Abstract: A convection oven is given a lower profile so that two ovens may be stacked without exceeding a height so that the uppermost of the stacked ovens may be comfortably reached by a relatively short person. Also, the oven requires less floor space for installation and operation. The height of the oven is reduced by placing inshot burners at an inlet to the oven. Heretofore, the burners were placed under the oven, which increased the space which must be provided to enclose the burner, and therefore the overall height of the burner. The height of the oven is reduced by allowing the flue gas flow from front to rear before entering the cooking cavity. Heretofore, the flue gas flowed from under the cooking cavity to the sides and up towards the top of the cooking cavity. From there, it traveled to the top of the cooking cavity before entering the cooking cavity itself. Cool ambient air is blown over oven controls in order to cool them before the air is heated by the burners.

Abstract: A conveyor oven has a modulating gas valve which raises and lowers the thermal output of a burner that heats the oven. A bypass line passes a minimum amount of gas to prevent the burner from completely shutting down during periods while the oven remains above a threshold demand for more heat. Electrical isolation is provided between temperature controlling devices to prevent an electrical feed back which might otherwise prevent a complete shut down of the oven during hazardous conditions.