Abstract: Method and apparatus for dispensing a liquid agricultural agent at a desired rate. A source of the liquid is pressurized and passed in parallel though at least one regulating capillary tube of such diameter and length as to regulate the rate of dispensing of the liquid at the desired rate. A pressure of the liquid is sensed and controlled for the purpose of adjusting the above-mentioned flow rate. A flow rate of the liquid is sensed and used with the sensed pressure to detect and alert a user of possible problems in the system, such as clogging of a dispensing outlet. A ground speed of the farm tractor which is transporting the system can he sensed in order to calculate the appropriate flow rate. A geographical location a farm machine in order to facilitate "prescription farming". The liquid may be injected and mixed with a carrier, and the mixing can be done in close proximity to an outlet orifice.

Abstract: A fluid regulator has two valve bodies (24, 25) placed opposite and cooperating with two openings (22, 23) for controlling the fluid flow from an inlet chamber to two outlet chambers. A spindle (34) interconnects the valve bodies (24, 25) at a predetermined mutual distance forming a spindle assembly. Each valve body and each opening form a passage (30, 31), the sum of the areas of the two passages being constant, but adjustable by a handle (9). The spindle assembly is freely moveable in the axial direction under the influence of the pressures across the openings acting upon the valve bodies so that the pressure drop times the area of each opening is equal for the two openings, and the fluid flow from the inlet chamber is divided into two fluid flows to the outlet chambers. The fluid regulator is intended to be used in an agricultural sprayer for distribution of a fluid composition to soil to be treated. The agricultural sprayer comprises a tank (2), a pump (6), the fluid regulator, and a plurality of nozzles.

Abstract: A feedback air pressure sensing system is described, for use with spray guns, comprising an air pressure feedback line (1), an air regulator (2) with an air cap (3). Air is supplied from air line (4) via regulator (2) to a dual air-feedback valve (5) operated by trigger (6). Air continues along line (7) to spreader control valve (8) supplying fan air to spray gun cap (3). Air is also fed via line (9) to supply atomising air to air cap (3). The regulator (2) comprises a body (13), an inlet (16) for a main air supply to first (14) and second (15) air chambers, an inlet for feedback air to a third air chamber (26), a diaphragm (19) between outlet chamber (25) and a pilot chamber (27), the diaphragm (19) being supported in the regulator body (13) by a spring-loaded valve (18), and spring loaded adjustment means (24).

Abstract: An improved fluid bypass valve includes a valve housing having an inlet port, an outlet port and a bypass port, all of which are in fluid communication with a valve chamber within the valve housing. A shuttle having a fluid passage therein is disposed within the valve chamber and moves between a first travel limit position, in which fluid communication between the fluid passage and the bypass port is blocked and a second travel limit position, in which such fluid communication is permitted. First and second fluid seals are disposed in contact with interior surfaces of the valve housing on opposite sides of the bypass port, and the shuttle is disposed in sealing and sliding engagement with both the first and second fluid seals when the shuttle is in the first and second travel limit positions.

Abstract: A pressure jet cleaning appliance having a pressure pump (10) driven by a drive (11). The appliance includes a conduit having a primary line (14) for directing fluid into a spray gun (15) and a bypass line (19) for recycling fluid through the conduit when the spray gun is turned off. A control valve (18) has a reciprocal piston (28) responsive to fluid pressure within the primary line such that the piston moves into a closed position thereby directing fluid through the bypass line when the spray gun is turned off. The piston is directly connected to a control element (22) in the drive such that movement of the piston is translated into displacement of the control element. With this configuration, the piston actuates the control element to reduce the speed of the drive when the piston is in the closed position and to increase the speed of the drive when the piston is in the open position.

Abstract: In accordance with a preferred embodiment of the invention, a solenoid operated unit fuel injector, for internal combustion engines of the type which are capable of having distinct timing, metering and injection periods, and in which the same supply line serves for the delivery of fuel to both a timing chamber and a metering chamber, is improved by providing a drilling in the injector barrel which leads directly from the timing fluid flow portion of the fuel supply circuit to an injector fuel drain path, and mounting a C-shaped spring valve on the injector body for controlling dumping of fuel through the drilling at a location above that of the timing and metering spill ports.

Abstract: A relief valve is built into the nozzle port of a fuel pump for an oil burner and opens to relieve pressure in the fuel supply line and prevent oil from dripping out of the burner nozzle when the pump is shut down. The relief valve comprises a ball which is normally held in a closed position by an arcuate leaf spring wrapped partially around the nozzle port.

Abstract: Fuel injection nozzles used for reducing NOx in gas turbine engines has incorporated a variety of expensive and complicated techniques. For example, systems use schemes for introducing more air into the primary combustion zone, recirculating cooled exhaust products into the combustion zone and injecting water spray into the combustion zone. The present fuel injector (60,166) reduces the formation of carbon monoxide, unburned hydrocarbons and nitrogen oxides within the combustion zone by controlling the premix air/fuel ratio and more explicitly by controlling the air portion of the air/fuel ratio over the entire operating range of the engine (10).

Abstract: An improved apparatus for delivering compressed particulate solid fire fighting agent includes a pneumatic system for entraining particulate fire fighting agent in a high pressure gas stream, compressing the agent into quasi-discrete quasi-solid slugs, and delivering the compressed slugs in a constant stream at a high rate of speed to the center of the fire being fought from a safe distance. The system includes a high pressure gas supply, a pressure regulator, a pressure compensator, a pressure sink, an agent storage vessel, and a multi-stage delivery nozzle including a pressure imbalance mechanism. Particulate agent is sequentially compressed in the multiple nozzle stages by virtue of a pulsating gas supply effect, and ejected in a constant stream of solid slugs at speeds near or above Mach 1.

Abstract: A control system for a mechanically-driven liquid pump coupled to an air spray gun wherein the control system includes an air pressure monitor to detect air flow to the spray gun and an electrically-operated solenoid valve to relieve liquid pressure in the spray gun liquid delivery line when the spray gun is inoperable, and to control a clutch mechanism to drive the pump when the spray gun is operable or when the pump is being primed; the air pressure monitor including a diaphragm-operated switch connected to permit the diaphragm to detect air flow to the spray gun.

Abstract: The invention is directed to a process for controlling product yields in a fluid catalytic cracker unit. In particular, the invention is directed to a process wherein the introduction of feed into a catalytic cracking zone is effected by feed injectors which optimize the atomization of the feed in order to achieve yield and/or quality objectives.

Abstract: A control system for a mechanically-driven liquid pump coupled to an air spray gun wherein the control system includes an air pressure monitor to detect air flow to the spray gun and an electrically-operated solenoid valve to relieve liquid pressure in the spray gun liquid delivery line when the spray gun is inoperable, and to control a clutch mechanism to drive the pump when the spray gun is operable or when the pump is being primed.

Abstract: A spray head (1) for a sink faucet (2) or the like that is suited for connection to a low-pressure storage tank (open hot water storage tank), with a water feed (4), a normal jet discharge (7) placed centrally in particular, a spray discharge (9) placed in particular surrounding normal jet discharge (7) concentrically and with a multiplicity of small spray holes (10), and a reversing valve (13) in which, in the normal position, reversing valve (13) connects normal jet discharge (7) to water feed (4) and separates spray discharge (9) from water feed (4) and, in a spray position, connects spray discharge (9) to water feed (4) and separates normal jet discharge (7) from water feed (4), is completely suited for use in connection with a low-pressure storage tank by a bypass pipe (21) that acts in the spray position being provided in reversing valve (13) between water feed (4) and normal jet discharge (7) and the flow resistance of bypass pipe (21) being greater than the flow resistance of spray discharge (9) when

Abstract: An adjustable air pressure valve for placement in a compressed air hose. Positioning a knob determines the pressure exerted by a spring on a valve member which allows air above a predetermined pressure to escape from the hose to the atmosphere. The knob is incrementally moveable to provide incremental pressure changes.

Abstract: An overflow and automatic start-up system adapted for use with hydrokinetic amplifiers is disclosed. More particularly, the present invention relates to an overflow check system adapted to provide unit suspension and restart solely by manipulation of a discharge valve at a remote user location.

Abstract: In order to prevent dripping in an oil supply system for a burner nozzle there is provided a pump stop valve in the supply line that connects the pressure outlet of the pump to the burner nozzle and a nozzle shut-off valve in the supply line between the pump stop valve and the nozzle. A circulating valve is provided in parallel to the pump stop valve to open when the pressure between the pump stop valve and the nozzle shut off valve is higher than the pressure at the pump outlet. As a result if the oil in the supply line adjacent the nozzle expands, oil can return through the circulating valve to the line between the pump stop valve and the pump outlet.

Abstract: A safety exhaust valve equipped spray gun including a safety exhaust valve provided on the bottle cover above the bottle connecting portion for maintaining air pressure transmitted into the bottle body through an air induction hole within a limited range, by providing a steel ball which is removed from an air exhaust when the pressure exceeds the limited range so that excessive air pressure is exhausted through an exhausted hole and the inner pressure is constantly kept within the limited range. A pressure stabilizing bolt is provided on the air induction hole of the nozzle so that spraying is effectively achieved by providing a fine spraying effect. By means of this arrangement, the spray gun of the present invention insures against explosion and provides a maximum security effect and is practical for both high pressure and low pressure application.

Abstract: A multi-gun control valve apparatus for use in controlling a high pressure fluid in a multiple dump-style gun fluid blast system, the apparatus including a valve cartridge assembly, with a pressure throttling member and an adjusting assembly. The apparatus maintains system pressure when any of the guns are dumping fluid rather than blasting. The adjusting assembly includes a spring-biased plunger to bias the valve closure member into a partially closed or throttling position when a gun is dumping, thereby causing a pressure drop across the closure member. The adjusting assembly is used to manually adjust the clearance between the valve closure member and valve seat while the system is under pressure. High fluid pressure in the fluid line between a dump-style fluid blast gun and the multi-gun control valve opposes the spring-biased plunger and opens the valve closure member to provide free flow through the device when a gun is blasting fluid.

Abstract: A supply line for supplying a sealant from a sealant supply source to a sealing robot has pressure sensors and is coupled to relief valves through branch lines. If the pressure in the supply line excessively rises or drops, then the relief valves are opened to release the pressure from the supply line and the supply pump is inactivated. The pipes, devices, and pump on the supply line are therefore protected from damage. The sealing robot has an sealant applicator gun movable with respect to an article to which the sealant is to be applied by the sealing robot. A pump driving device is controlled to vary the rate at which the sealant is discharged from the pump as a function of the speed of relative movement of the sealant applicator gun with respect to the article.

Abstract: A fuel injection nozzle unit has an inwardly opening valve member which can be moved by fuel pressure in a chamber connected to a fuel inlet to allow fuel flow through an outlet orifice. In order to circulate fuel through the chamber a passage leads therefrom to a fuel outlet. A restrictor is located in the passage and the valve member acts to prevent flow through the passage when it is open to allow fuel flow through the outlet orifice.

Abstract: An enclosed slurry dispensing system employs a sealed pressurized reservoir for supplying slurry through a bypass chamber to a dispensing nozzle. Excess slurry is bypassed through the bypass chamber to an intermediate chamber. Slurry is allowed to return to the reservoir through a normally-closed check valve, closed by the higher pressure of the reservoir. The system is purged by opening the reservoir to the atmosphere, creating a sub-atmospheric pressure in the bypass chamber. Air is admitted through the nozzle to purge the nozzle of slurry. At the same time, the check valve opens and excess slurry returns to the reservoir from the intermediate chamber.

Abstract: A high pressure cleaning equipment will be described which can be operated by either hot water or superheated steam with the addition of cleaning chemicals as required. For increased safety of operation of the equipment, a safety valve is additionally provided together with, as required, a steam valve, which in the case of steam operation, directs only a noticeably reduced amount of cleaning fluid per unit of time to a heat exchanger which converts the cleaning fluid to steam.

Abstract: A diesel unit fuel injector includes a pump assembly having an externally actuated plunger reciprocable in a bushing which with the plunger defines a pump chamber, with flow therefrom during an injection cycle portion of the pump stroke being directed to a fuel injection nozzle of the assembly. The injection nozzle includes a needle type differential area injection valve that is normally biased to a valve closed position by a valve return spring which is positioned in a spring chamber and which is operatively connected to the opposite end of the injection valve.

Abstract: A pressure vessel for a backpack agricultural sprayer is mounted within a container of the sprayer and connected to the sprayer pump so that liquid from the container is forced under pressure into the pressure vessel for a spraying discharge therefrom. Sediment precipitated from herbicides or insecticides employing wettable powders tends to collect at the bottom of the pressure vessel and a combined sediment agitating and pressure regulating action is provided by a pressure regulator valve mounted in the pressure vessel and having a suction tube connected between the valve and the area of the pressure vessel where the precipitated sediment collects.

Abstract: In a windshield washing system for motor vehicles which includes a line for the supply of heated washing liquid to a spray nozzle, the line is part of a closed circulatory system which extends from a heating device in a reservoir tank to the spray nozzle in back and in which a pressure producer in case of need acts upon the washing liquid with an increased spray pressure, at which the spray nozzle releases washing liquid onto the surface to be cleaned.

Abstract: In high-pressure cleaning units with heating stages, i.e. with a possibility for circulating a partial flow of the forwardly pumped water through a constricted, heat-generating nozzle (74) in a return conduit to the pump's inlet side, the problem occurs that the entire water flow circulates at high pump pressure upon temporary interruption of ejection, which causes an inexpediently high heating of the water. By the invention, apparatus is provided for sensing this situation and thus block the return conduit (70,72), so that the pressure tends to rise; in this way, however, the cleaning unit's ordinary bypass valve (12) will sense that delivery from the pump (P) is totally blocked, whereby it connects the pump in bypass state in the ordinary way through a non-constricted bypass connection (14). In this way, ejection can be interrupted temporarily without any substantial heat accumulation in the circulating water, and another advantage is that the ejection conduit itself is pressure relieved in the situation.

Abstract: A mobile liquid spray apparatus comprises a wheeled frame of lightweight but sturdy construction which may be propelled manually over the ground or may be towed by a towing vehicle. The frame includes a height-adjustable horizontally extending spray boom, an attachment for a pair of vertical spray booms and a self-contained liquid supply system for delivering liquid under pressure selectively to the respective spray booms. The liquid supply system comprises a liquid supply tank on the frame, and a battery driven pump for delivering liquid under pressure from the tank selectively to the spray booms through a manually settable three-way valve. The system also includes a pressure regulator valve and pressure gauge for adjusting the spray pressure. The device may also include an auxiliary hand-held spray gun which may be used in place of one of the spray booms.

Abstract: A spraying system includes a screw conveyor to transmit material to be sprayed from a storage container to a spray nozzle. A predetermined torque is maintained on the screw to thereby maintain a predetermined pressure on the material within the conveyor, so that an instantaneous flow of material at a predetermined pressure can be obtained when the nozzle is opened. The pressure is preferably maintained by means of a hydraulic motor designed to stall at a predetermined torque. A heating jacket for housing heated oil surrounds the screw conveyor and provides heat necessary to maintain the material therein at a predetermined temperature.

Abstract: The present invention contemplates a fluid delivery system for use with one or more individual water blast guns, each of which have an auxiliary shut-off valve integral with the gun and also include electric circuit completion means for operating a pneumatic secondary shut-off valve in series with the high pressure fluid supply conduit feeding each gun. This series arrangement of first and second shut-off valves in the fluid conduit between the pump discharge and each individual gun assures a fail-safe shut-off system which gives the operator of each gun the assurance that upon release of the water blast gun trigger that cessation of the water blast from the gun nozzle will occur. Accordingly, the likelihood of the operator falling over backwards upon release of the gun trigger is eliminated and risk of a dropped runaway water blast gun that failed to shut-off is eliminated.

Abstract: A pair of positive displacement pumps are connected in series between a liquid fuel supply tank and a burner nozzle. Mechanically linked, identical variable orifices are interposed within the supply line between the pumps and the nozzle. A first pressure regulator is connected across the supply line between the pumps and a return line leading from the nozzle back to the supply tank. A pressure sensing line for the first pressure regulator is connected to the supply line on the discharge side of the second positive displacement pump to regulate the outlet pressure of the first pump. The discharge line for one of the variable orifices leads to the burner nozzle and forms part of the supply line, while the discharge line for the other variable orifice bears a second pressure regulator and connects to the return line.

Abstract: A fuel injection nozzle for internal combustion engines having a filter body inserted into the fuel inflow conduit, an injection valve and a check valve, which maintains a static pressure in the injection nozzle and can also perform a relief function for the prevention of after-injections. The check valve is integrated into the filter body thereby simplifying the final assembly of the injection nozzle. The filter body is advantageously embodied as a rod-type filter, which by the appropriate shaping of its jacket periphery forms gap-like spaces between itself and the surrounding wall of the nozzle holder through which spaces the fuel must pass such that it is deflected multiple times.

Abstract: A fuel injection device for a diesel engine or the like confines the fuel injection pressure to a predetermined range. Fuel is fed under pressure from a fuel supply source to a high pressure chamber to develop a pressure therein. An injection nozzle is mounted on a nozzle holder and has a nozzle hole for injection fuel in response to the pressure in the high pressure chamber. The nozzle holder has thereinside a low pressure chamber which communicates to the outside. An injection rate control valve is mounted in the nozzle holder for delivering fuel to the low pressure chamber on the elevation of the fuel pressure communicated to the high pressure chamber beyond a predetermined value.

Abstract: An apparatus for applying molten wax onto a printed circuit board travelling along a predetermined transfer path. The applied wax after solidification serves to fix the electric components mounted on the board, facilitating the succeeding operations such as cutting and soldering. The apparatus includes a vessel for containing a molten wax, a plurality of ejection nozzles arranged in a direction transverse to the transfer path, valve means connected to each of the ejection nozzles and operable so that the molten wax is ejection from each nozzle upon actuation of the corresponding valve means, and a pump, such as a gear pump, having a suction side in fluid communication with the vessel and a discharge side in fluid communication with each of the valve means. Means are provided for selectively rendering the valve means operable according to the width of the printed circuit board.

Abstract: A volume proportioning system includes a pressurized supply of a primary carrier liquid, one or more sources of concentrate, a proportioning interconnection between the carrier liquid and the sources of concentrate by which the proportions are controlled regardless of the flow rate or pressure of the carrier liquid, in which the carrier liquid also provides the motive power for moving the concentrate and the carrier liquid itself to an operator controlled discharge point, the discharge being infinitely variable under the control of an operator.

Abstract: A regulator-unloader for fluid systems comprising, in a housing; an inlet passageway; an outlet passageway connected to said inlet passageway; a piston movable within said outlet passageway; an outlet valve connected to said inlet passageway and to said outlet passageway outwardly of said piston; a bypass passageway connected to said inlet passageway; a main bypass valve spaced within said bypass passageway; and a rod spaced within said inlet passageway and connected at one end to said piston and at the other end to said bypass valve; said rod being pivotally mounted in the housing at a point intermediate its ends.

Abstract: A control valve and switch assembly for automatic control of the pressure in a high pressure fluid system, such as in car washing apparatus, and comprising a housing having a fluid chamber therein providing communication between a pressure fluid source, such as a pump, and a fluid discharge valve, such as a spray nozzle, a fluid outlet passage provided in the housing in communication with the pressure chamber; a primary pressure switch secured to the housing and open to the pressure within the pressure chamber for selective opening and closing; the primary pressure switch being operably connected between a power supply and a motor starter for selective activation of the motor starter; an unloader valve in communication with the outlet passage and responsive to the pressure therein for selective opening to bleed excessive pressure from the pressure chamber to a fluid return line, and a secondary pressure switch secured to the housing and open to the return pressure; the secondary pressure switch being operably

Abstract: A means to cut off the feeding of combustible fluid under pressure to an injector needle of a diesel engine which is stuck in the open position.The end portion of a push rod which insures the closing of the injector needle under the push of a spring includes a throat which it slides across an orifice of a predetermined cross-sectional area of value S. The orifice is in communication with a chamber wherein is mounted a differential piston. The chamber also is connected to a discharge passage by a calibrated orifice whose cross-section S is directly related to the cross-section of the orifice. At the end of each injection stroke, the throat terminates communication with the orifice of cross-section S and the pressure in the chamber is reduced before the piston is displaced.

Abstract: A control device and method for opening and closing the nozzle of a fuel injector. The control device includes first and second cavities which are formed in the body of the fuel injector, with the second cavity being located close to the nozzle. First and second variable pressure supply chambers are connected to the nozzle and to the two cavities by several fluid passages. A spool valve and a needle valve are positioned in the first and second cavities, respectively, with the spool valve abutting a stem which projects into and terminating in the second cavity. Also situated in the second cavity between the stem and the needle valve is a spring which forms a link therebetween. The spool valve is pressure-actuated by a difference of pressure in the first and second pressure chambers to move between an open and a closed position. In the open position, fluid flow from one of the pressure chambers is permitted through the spool valve and to the second cavity.

Abstract: A device for obtaining a uniform application of marking material on streets, squares, or the like and, in particular, a marking machine with travel dependent driven, statically-operating pump system for the marking material, is provided. The device prevents the occurrence of substantial pressure fluctuations with respect to the given system pressure during opening and closing of an applicator nozzle and serves to influence the feeding flow to the nozzle.

Abstract: A throttle body fuel injection system has a pressure regulator which reduces the pressure of the fuel supplied to its electromagnetic injector as the engine induction passage pressure decreases.

Abstract: A relief valve which maintains generally constant pressure in a fluid system for a wide range of flow rates through the system. When the valve opens as the pressure in the system exceeds a predetermined value, the flow about the valve plug is allowed to impinge on itself adjacent to the bottom surface of the plug to create a stagnation pressure on the plug which maintains generally constant liquid pressure within the valve for different plug settings even though the spring force on the plug increases as the flow increases and the plug is lifted further from its seat.

Abstract: A fluid injector, for example for injecting liquid fuel into a combustion chamber, comprises a valve housing and an injector assembly which may be removably mounted on the valve housing. The injector assembly includes discharging means for discharging fluid from the injector assembly, ducting for conveying the fluid between the valve housing and the discharging means and a control valve movable to a first position in response to flow of the fluid in a first direction through the ducting to close the discharging means and return the fluid from the discharging means to the valve housing and movable to a second position in response to flow of the fluid in a second direction through the ducting to open the discharging means to allow at least some of the fluid conveyed to the discharging means to be discharged therefrom and to return any surplus fluid to the valve housing. Provided in the valve housing are inlet and outlet passages for conveying the fluid into and from the valve housing, and a change-over valve.

Abstract: An airless paint or material spray system having a pressure sensor and regulator for controlling the pressure of paint flowing from a paint pump to an airless spray gun. The pressure sensor and regulator includes three contiguous flexing diaphragms in a material chamber in the outlet flow line of the pump with the outermost diaphragm in direct contact with material being constructed of a thin plastic impervious to attack by common painting or coating materials. The two other diaphragms are rubber coated fabric diaphragms that axially position a precision steel rod movably mounted in a low clearance bore in a regulator housing. The axial movement of the precision rod is converted to rotational movement by an adjustably spring biased, pivotally mounted member in the housing having a universal connection with the precision rod. A normally closed snap action switch in the housing is actuated after a predetermined axial travel of the precision rod by an amplifier bar connected to the pivotally mounted member.

Abstract: A forward motion arresting means is added to a fluid powered lance to reduce the harmful effect of the stopping of the lance forward motion. A plug member mounted on the lance mates with a body member within the housing to prevent fluid flow and reduce the lance forward motion. Rearward motion arresting is achieved by the addition of a reservoir portion which acts as a hydraulic stop in conjunction with the lance piston.

Abstract: An accurate amount of a chemical concentrate is injected and mixed into a pressurized carrier liquid stream and dispensed by employment of two calibrated in-line valves in the line siphoning the concentrate to a siphon injector. The valves are so calibrated that the operator need only set the first in-line valve at the percentage of active ingredient in the concentrate and set the second valve at the percentage of active ingredient desired in the mixture to precisely reduce the flow rate of the concentrate in the siphon line and provide an accurately mixed finished liquid at the dispensing end of the system. Such a system is particularly adapted for use in the pest control industry.

Abstract: A method and apparatus for the diversion of fluid flow at reduced pressure out of a high pressure fluid delivery system when the discharge of the system is closed. A bypass valve having a movable piston oriented transverse to the flow direction and a slidable seal oriented parallel to the flow direction is located between the system pump and discharge. The movable piston has two working surfaces of different areas which define planes parallel to the flow direction so that the working surfaces and therewith the piston are generally responsive only to static fluid pressure. The slidable seal is responsive to dynamic fluid pressure so that when the discharge is closed and the dynamic fluid pressure thereby reduced, the seal moves to interrupt fluid communication between the two working surfaces of the piston.

Abstract: An injection system for a Diesel internal combustion engine which includes an injection pump with injection lines, injection valves with valve needles opening inwardly against spring pressure and leakage oil lines starting from the injection valve; a device consisting of a flow-direction sensor detecting the direction of flow and of a discharge valve is thereby arranged in each injection line, preferably in proximity of the injection valve, which discharges the pump volume of the injection valve resulting at the end of the injection operation into the leakage oil line.

Abstract: In a high pressure liquid system such as those commonly used for cleaning and scaling, a feed pump is connected in series with a high pressure pump. The discharge from the high pressure pump is controlled by a fail-safe pressure responsive valve which is responsive to feed pump pressure.

Abstract: A fluid spraying apparatus, such as for use in paint spraying and the like, including a high pressure diaphragm pump, a safety and pressure adjustment valve system, and a high pressure safety spray gun. The valve system includes a valve for maintaining a desired pressure relationship between the sprayed fluid side of the system and the pumping fluid section of the high pressure diaphragm pump. The high pressure safety gun includes a pressure-responsive locking barrel portion which prevents access to the spray tip while the fluid being sprayed is under pressure.