Abstract: A well pumping system includes a pivotally mounted walking beam and "horsehead" connected to a downhole pump by a pump rod in the conventional manner. A hydraulic lift piston and cylinder and a pneumatic balance piston and cylinder are connected to the walking beam. A process control computer controls input signals to a hydraulic control valve for controlling the hydraulic cylinder rate and direction of travel to provide corresponding control over the motion of the walking beam. The computer receives input information from a position sensor indicating the displacement of the beam in its range of travel. The computer program also is responsive to a timer for determining actual stroke rate and acceleration of the beam. The computer monitors and controls operation of the hydraulics and pneumatics as the pumping unit produces the lift necessary to extract fluid from the well.

Abstract: A lubricant pump for supplying lubricant to an internal combustion engine, the pump comprising a housing defining a pump chamber, an inlet which is adapted to communicate with a source of lubricant and which communicates with the pump chamber, and an outlet which is adapted to communicate with the internal combustion engine and which communicates with the pump chamber, the housing also at least partially defining a fluid chamber, a source of fluid under pressure, a solenoid for selectively and alternatively affording and preventing communication of the fluid chamber with the fluid source, and a pumping member for drawing lubricant into the pump chamber in response to communication of the fluid chamber with the fluid source and for forcing lubricant out of the pump chamber in the absence of communication between the fluid chamber and the fluid source.

Abstract: A dosing system for precisely mixing two liquids in a predetermined volumetric relationship includes a flow meter having a fluid inlet, a fluid outlet, and two intermeshed counter-rotating gears positioned between the inlet and outlet. When a first fluid is directed from the inlet to the outlet, the first fluid causes the gears to turn, and the gears turn a predetermined amount for each unit of first fluid directed through the f low meter. The rotor of a peristaltic pump is coupled to one of the gears of the flow meter, such that for each increment of rotation of the gear, the rotor turns to pump a predetermined amount of a second fluid through the peristaltic pump. The outlets of the two pumps are in fluid communication, to permit mixing of the predetermined amounts of first and second fluid.

Abstract: Pumping apparatus for recovering a first liquid, such as a pollutant, floating on a second liquid, such as ground water. A pump immersed in the second liquid, or ground water, operates to produce a cone of depression and discharge the second liquid into a pressure vessel. A variable volume chamber inside the pressure vessel contracts and displaces any contents through an outlet conduit to a product discharge point. When the pump turns off, the variable volume chamber expands and draws product into the chamber to be driven from the chamber during successive pumping operations. Over time periodic pumping operations cause the variable volume chamber to recover the first liquid and move it to a discharge point.

Abstract: A method and apparatus for controlling the discharge time of a fluid activated diaphragm pump. The control system regulates the discharge time, by measuring the discharge time and comparing the measured time with a predetermined desired discharge time. The control system includes, inter alia, a programmable logic controller, an upper and lower proximity switch, a target, a rod to hold the target, a pilot controlled pressure regulator, a set of digitally controlled solenoids which control a pilot valve, a solenoid, and a pressure switch. The rod is secured to the diaphragm of the diaphragm pump, and the proximity switches respond to the movement of the rod to detect the movement, or stroke, of the diaphragm. The pressure supplied to the diaphragm pump is automatically, and continuously, adjusted to maintain a desired discharge time.

Abstract: A device for dispensing oils, antifreeze and other fluids from drums or other bulk containers has a rotary air motor which powers a gerotor-type pumping element. The pumping element has at least one magnet thereon and an electronics package is provided which counts the number of magnetic pulses which occur during the rotation of the gerotor and converts it over to the quantity of material pumped. A valve controls the flow of air to the air motor which in turn allows an operator to control the dispensing of fluid from the outlet of the pumping element.

Abstract: A valve battery, including a plurality of base plates, each having a generally polygonal outer contour, a window-shaped recess therein, and two side faces, a face of one plate corresponding a face of an adjacent plate and sealingly engaging one another, closure plates being provided on the free end surfaces, a plurality of electrically actuatable individual valves mounted in the base plates, each having an inlet port, an outlet port, and an electrical connection, the mounted valves not protruding from the faces of the base plates, at least one of the base plates (4) having an associated vacuum device (31) and a compressed air connection (32) on one of the end surfaces for creating a vacuum, being interconnected for control by another of the said base plates (1) having one or more associated valves which are continuous valves (14), an inlet connection associated with each of the base plates, provided on one of the elongated side surfaces thereof, an outlet connection (A1,A2) associated with each of the valves,

Abstract: A safety shutdown circuit for a pneumatic pump system. The pump system includes a manifold assembly for discharging pumped liquid. The liquid is discharged from the system by a reciprocating piston apparatus which drives a liquid pump cylinder. The pump system is provided with a pneumatic safety circuit for monitoring the stroke time or rate of the reciprocating air cylinder. The safety circuit includes a safety shutdown valve and a pneumatic timer associated with the shutdown valve. The pneumatic timer vents air supply within the safety circuit after a predetermined time interval. If a leak or failure occurs in the pump system, the reciprocating piston apparatus will complete a stroke in less time than the predetermined time as a result of the pressure loss incident to the leak or failure. In such event, the air supply within the safety circuit is directed through the shutdown valve to the pump system START valve to deactivate the system.

Abstract: Apparatus for periodically drawing accumulated sludge (12) from a settlement tank (10) includes a hydraulically powered ram type positive displacement pump (14), operation thereof being controlled automatically in a timed or other sequence in response to signals derived from a pressure transducer (34), conveniently in the hydraulic supply line (24), said signals being a function of the pressure exerted by the pump ram (22) in operation and hence the density or other properties of the material being handled by the pump, a higher pressure showing the presence of sludge and a lower pressure its absence.

Abstract: A fluid pumping apparatus and system including a double acting diaphragm pumping device in which each pumping component has a pair of spaced apart diaphragms defining a containment chamber and all exposed surfaces in the pumping chamber and the containment chamber are made of an inert plastic material, a fluid sensor extending into each containment chamber for sensing the presence of unwanted fluids therein, and a pump control system for activating the pumping apparatus and responding to an output signal generated by either sensor to deactivate the pumping apparatus in the event of leakage of fluid into either containment chamber.

Abstract: A pumping apparatus comprises a fluid end cylinder carrying a double-acting piston which is reciprocated by a hydraulic servo actuator to provide an expanded flow range ability for metering fluids. The hydraulic servo actuator comprises: a hydraulic cylinder carrying a drive piston connected to the fluid end piston; a servo valve; a position transducer; and a microprocessor-based controller. The controller is programmed to accommodate accleration and deceleration of the extend and retract phases of a pump cycle to maintain constant average flow rate out of the fluid end. A control apparatus for controlling a pump and a related method are also disclosed.

Abstract: A component deficiency safety device for two-component sprayer systems comprised of pneumatic and hydraulic/mechanical detection and actuation members. The safety device is adapted for placement in the compressed air line of a spray system, in particular, in the compressed air line that powers the spray component air motors and pumps. A pneumatically controlled main valve cuts-off the compressed air to the air motors upon detection of a deficiency condition. The main valve is controlled through a pneumatic control input which is fed from the output of an OR valve having a start-up input and a normal operation/safety shut-down input. Individual pressure transducer/valve assemblies are associated with each component supply line. The outputs from these assemblies form separate inputs to an AND valve which, in turn, enables the main valve only when both transducer/valve assemblies indicate the presence of proper component supply pressure.

Abstract: An above-ground storage system, especially for use with hazardous materials is disclosed. The system includes a first inner tank and a second outer tank. An air-operated diaphragm pump is used to fill the tank. In order to preent overfilling of the tank and, therefore environmental contamination, a valve is installed in the air supply line to the air pump. The valve is operated by a float within the tank. When the float becomes submerged in liquid the valve is closed by an arm connected to the float.

Abstract: An air operated hydraulic fluid pump having an air pressure operated motor drivingly connected to a hydraulic fluid pump to drive the hydraulic fluid pump, and an airflow control valve controlling the supply of air from an air pressure source to the air pressure operated motor, the airflow control valve causing an increase in the supply of air to the air valve pressure operated motor in proportion to increase in the hydraulic fluid pressure generated by the hydraulic fluid pump.

Abstract: A lubricating delivery system includes a positive displacement lubricant pump and fluid flow measuring means for monitoring the output of the pump. The pump is a miniature injection pump and the measuring means includes switch means responsive to movement of the check valve provided at the output of such a pump. Because such a system provides flow measurement by a single digital input to a programmable controller, numerous pumps may be utilized to individually supply lubricant to separate portions of a machine and all may be monitored for output flow without tying up an inordinate portion of the PC input circuitry, which is typically required to additionally control the machine being lubricated.

Abstract: An oil cable pumping plant including at least one oil tank and at least one air/gas driven piston type oil pump connected to the oil tank, at least one air/gas source connected to the air/gas inlet of the pump via a pressure control. An exit for the air/gas as well as an oil exit are connected to at least one oil filled cable, and an oil flow indicator. The pump in its normal operating condition provides a predetermined oil pressure at its outlet. An oil flow control is interconnected between the oil flow indicator and the air/gas pressure control for controlling the oil.

Abstract: This invention relates to a pressure equalizer for use in a feeder designed to feed ceramic enamel, or paint in general, to a spray gun of an automatic type in general, and in particular to a spray gun associated with an enamelling or painting robot. The feeder is of the type utilizing an air-operated pump and the pressure equalizer is mounted close to the spray gun. The pressure equalizer includes a pressure sensing element for sensing the pressure at which enamel or paint is fed to a spray gun, the sensing element applying the pressure changes to a throttling member which is fitted in the line supplying compressed air to the air-operated pump so as to ensure that a controlled constant flow of enamel or paint is fed to the associated spray gun for any working position thereof.

Abstract: An electropneumatic converter is provided comprising a gear pump. The two othed wheels are driven by two electric motors rotating at high speed in opposite directions. The control circuits for each of the motors are independent and a single motor may drive the pump permanently.The converter is used, for example in an activator for a cardiac module or artificial heart.

Abstract: A fluid operated pump comprising a housing including first and second cylinders. First and second pistons are rigidly fixed to each other and situated in their respective cylinders, the cylinders alternately receiving pressurized fluid for operating the pump. The pump includes novel valving means and novel seals.

Abstract: An apparatus for analyzing a process stream (1) via supercritical fluid chromatography including container means (10), extraction means (50) for drawing a sample volume from the process stream and injecting the sample volume into the supercritical fluid to form a dilute mix (5), analyzer means (70) for analyzing the dilute mix via supercritical fluid chromatography, sample inlet valve means (60) for receiving the dilute mix from the extraction means (50) and supplying a portion of the dilute mix to the analyzer means (70), pneumatically driven piston-type pump means (30) for drawing the substance from the container means (10) and delivering same under pressure either to the extraction means (50) or to the analyzer means (70) as desired, and control means (40) for supplying low pressure air to the pump means (30) in a controlled manner so as to draw the substance from the container means (10) and maintain the substance at a desired pressure above the supercritical pressure for delivery to the analyzer means (7

Abstract: An apparatus for analyzing a process stream (1) via supercritical fluid chromatography including container means (10), extraction means (50) for drawing a known sample volume from the process stream and injecting the sample volume into a known volume of supercritical fluid to form a dilute mix (5), analyzer means (70) for analyzing the dilute mix via supercritical fluid chromatography, sample inlet valve means (60) for receiving the dilute mix from the extraction means (50) and supplying a portion of the dilute mix to the analyzer means (70), pneumatically driven piston-type pump means (30) for drawing the substance from the container means (10) and delivering same under pressure either to the extraction means (50) or to the analyzer means (70) as desired, and control means (40) for supplying low pressure air to the pump means (30) in a controlled manner so as to draw the substance from the container means (10) and maintain the substance at a desired pressure above the supercritical pressure for delivery to t

Abstract: Pump system, method and apparatus for detecting a well pump off condition and for operating a well with cycles of alternate short pumping operation and outgassing operation to substantially reduce well pump off.

Abstract: A pumping system for producing uniform discharge and suction rates includes a pump connected to a supply of hydraulic fluid to deliver hydraulic control fluid at a selectable flow rate to a proportioning valve. The proportioning valve divides the flow of hydraulic fluid into two resulting flows, each of which is utilized via a four-way valve to drive a piston within a hydraulic cylinder. The positions of the pistons within the cylinders are detected and used to control the proportioning valve such that each piston is imparted with a velocity that varies in a sinusoidal manner in response to the hydraulic fluid delivered to it by the porportioning valve. Sensing of the piston positions and control of the proportioning valve may be accomplished mechanically by a system of cams driven by the pistons, or electronically by a microprocessor receiving signals from transducers coupled to the pistons.

Abstract: Disclosed is a fan drive, in particular one for cooling installations of rail vehicles. The fan drive comprises a hydraulic motor and a control valve which regulates a bypass as a function of temperature, thus affecting the flow of a pressure medium driving the motor. The control valve comprises a control piston subjected to a control pressure in the direction of closing the bypass, and a counterbalancing pressure in the opposite direction from the source of the pressure medium. The control valve also comprises a control spring which biases the control piston in the direction of closing the valve, and a pilot valve which affects the control pressure. The pilot valve is actuated by an electromechanical servo component. The pilot valve is located in an insert which is arranged within the control piston. A central bore of the control piston is slidingly guided on the convex surface of the insert so as to form a seal.

Abstract: A Method, System and Apparatus is disclosed for pumping liquid from a well such that vapor lock of the pump cannot occur due to gas or steam and such that the pump strokes only in response to the production rate of well liquid. The pump can be used for lifting heavy oils heated by steam floods or the like as well as for pumping liquids from conventional wells. Reduced pump wear, reduced energy requirements, reduced maintenance and the automatic adaption to changing well production rates are among the objects of this invention.

Abstract: An apparatus for controlling flow of a fluid having two speed-controlled positive displacement devices for supplying a load with fluid under pressure from a supply at a different pressure with interposed variable-volume buffer containers.

Abstract: A water-powered positive displacement auxiliary sump pump has a drive water inlet connected to the municipal water supply via a float actuated pilot valve. The pump is designed to be constructed chiefly of molded plastic supported by an exit manifold connected to the discharge line of an existing electrical sump pump. The presently preferred design is a rotary sliding vane pump having drive water and pump water chambers.

Abstract: A control device associated with a pneumatically-driven demand pump comprising a valve system which shuts off the gas which drives the pneumatic pump in response to a pressure-sensitive diaphragm which detects variations in pressure in the fluid output from the pump. The pressure-sensitive diaphragm serves the dual function of suppressing surges of liquid flow from the pump and stopping the pump when the liquid pressure drops below a predetermined minimum by closing a valve to shut off the gas.

Abstract: A multiple-mode, multiplex pumping apparatus includes circuit control elements for initializing the apparatus by placing each of the pistons and plungers in each pumping section of the multiplex pumping apparatus at a respective initial starting point. The pumping apparatus also includes electronic circuit elements for controlling the inlet valves, exhaust valves and precompression valves of the hydraulic circuit of the pumping apparatus. The apparatus includes phase control circuit elements for controlling the separation of the leading edges of the plungers of two of the pumping sections of the apparatus when the apparatus is operating as a quadruplex pump. The pumping apparatus also includes elecrtronic circuit elements for insuring that each plunger of each pumping section stops at a fixed stopping point. The apparatus also includes electronic circuit elements for controlling the volume of fluid in the rod end portions of each of the pumping sections.

Abstract: A well point pumping system including a series of well points installed in an area of the ground which is to be dewatered or dried out. This system and its apparatus include an enclosed tank which can be located closely adjacent the well points which are often in a dirty, wet and/or remote area which often has difficult access. Also, the dewatering areas may be located at different levels below the ground surface. Usually the apparatus is subjected to severe abuse from handling, being moved about or from other machinery in the area. Furthermore, it may be difficult to install or remove the apparatus. The present system and apparatus include an enclosed tank which is capable of withstanding abuse and which can be located in the dirty working area and remotely from its power source. The tank encloses an impeller type water pump assembly, and also encloses a vacuum pump and its drive motor which create the required vacuum in the tank to cause water to be inducted into the tank from the well points.

Abstract: A method, system and apparatus is disclosed for pumping liquid from a well such that vapor lock of the pump cannot occur due to gas or steam and such that the pump strokes only in response to the production rate of well liquid. The pump can be used for lifting heavy oils heated by steam floods or the like as well as for pumping liquids from conventional wells. Reduced pump wear, reduced energy requirements, reduced maintenance and the automatic adaption to changing well production rates are among the objects of this invention.

Abstract: An emergency shutdown system for an air-balanced pumping unit which includes a pump motor, a walking beam driven by the pump motor, a rod string reciprocated by the beam, and an air-balance cylinder and an air receiver which together define an air spring for storing energy from the beam is disclosed. A lever arm is pivotally mounted on the walking beam and attached at one end to the rod string so that a rotational moment is exerted in proportion to the weight of the rod string. Such rotational moment is opposed by an air bag, the output force of the air bag being adjustable within the expected range of the rotational moment. Thus, by properly adjusting the air bag, loss of load on the rod string results in movement of the lever arm. A shutdown valve is operatively connected to the lever arm and bleeds air from the air cylinder upon loss of load.

Abstract: An air pressure operated automatic lubricating gun is simplified in its conents and in its assembly to such an extent that this automatic gun can compete economically with manually operated lubricating guns. This improvement has been made possible by locating an air pressure chamber in a main pipe above the high pressure pump and below the air pressure operated motor. The riser pipe for the lubricant is arranged off-center to the central longitudinal axis so as not to interfere with the operation of the centrally located pump piston. The riser pipe passes through the air pressure chamber for a compact assembly. The air pressure supply control means are arranged in the air pressure chamber.

Abstract: A hydraulic fan control for controlling air ventilation in a building having a plurality of fans operated by associated hydraulic motors which are connected in parallel and driven by a single pump and electric motor unit through a hydraulic fluid circuit. The speed of the fans is proportional to the volume of fluid flowing through the associated hydraulic motors per unit time, i.e., the rate of fluid flow. The volume of fluid is regulated by a shunt flow divider valve included in the hydraulic circuit and connected in parallel with the hydraulic motors. The shunt flow divider valve is in turn controlled by an electrical drive circuit responsive to variations in the ambient temperature of the air in the building.

Abstract: A system for supplying foam liquid concentrate via a concentrate pump to one or more water pump discharge outlets. The concentrate pump is powered by a variable output hydraulic drive which in turn is automatically modulated independently of the level of operation of the water pump by a control system which is responsive both to the water pressure developed by the water pump and to the foam liquid concentrate pressure developed by the concentrate pump.

Abstract: An air timing device for a high pressure reciprocating injector pump 14 employing a piston or movable wall 50 and orifice 48 combination that is mechanically reset on the suction stroke of the pump includes a bellows 42 defining a variable volume chamber 44 including at least one movable wall. An adjustable orifice 46 in parallel with a check valve is defined in the chamber to provide adjustable flow out of the chamber and full flow through the check valve into the chamber. The wall is connected to a piston 18 of the reciprocating pump by an arm 38 that is fixedly secured to the piston and slideably secured to the wall. A selector valve 62 is also included for directing supply fluid to a selected side of the pump piston to reciprocate the pump. The valve includes a spool valve connected to the wall by a second arm.

Abstract: In a drive system of a hydraulically driven reciprocating piston gas compressor a gas pressure control signal to oil pressure control signal translating device supplied with hydraulic pressure oil during pressure transients caused by piston reversal.

Abstract: A constant pressure system for pumping a coal slurry includes a slurry pump mechanically driven by a hydraulic motor which, in turn, is driven by a hydraulic pump. The output of the hydraulic pump is controlled by a pressure sensitive flow control valve that maintains the hydraulic fluid pressure drop as a constant across the hydraulic motor. The system assures a constant hydraulic motor output torque, driving the slurry pump at a constant delivery pressure.

Abstract: A double acting hydraulically driven gas compressor using a free floating piston the reciprocating action of which is being controlled by a valve system responsive to pressure peaks, generated in hydraulic system on piston reversal, the pressure level of those peaks being higher by a constant pressure differential than the discharge pressure of the gas compressor.

Abstract: An automatic engine shut down device is operable in a system of the type including a pump having a suction inlet and a pressure discharge for discharging a liquid at a operational pressure, an engine for driving the pump, the engine being operable by an engine operating fluid, the engine including a control member for controlling the supply of engine operating fluid to the engine, the control member being movable between a first open position allowing operation of the engine and a second closed position shutting down operation of the engine. The automatic shut down device is operable, upon the removal or substantial reduction of suction at the inlet of the pump, to automatically terminate operation of the engine and thereby of the pump.

Abstract: An air timing device for a high pressure reciprocating injector pump 14 employing a piston or movable wall 50 and orifice 48 combination that is mechanically reset on the suction stroke of the pump includes a bellows 42 defining a variable volume chamber 44 including at least one movable wall. An adjustable orifice 46 in parallel with a check valve is defined in the chamber to provide adjustable flow out of the chamber and full flow through the check valve into the chamber. The wall is connected to a piston 18 of the reciprocating pump by an arm 38 that is fixedly secured to the piston and slideably secured to the wall. A selector valve 62 is also included for directing supply fluid to a selected side of the pump piston to reciprocate the pump. The valve includes a spool valve connected to the wall by a second arm.

Abstract: A method and apparatus for controlling the fluid pumping rate of an internal combustion engine driven pumping means taking suction from a zone of fluid under pressure whereby a substantially constant fluid pressure is maintained within said zone. The vacuum produced by the internal combustion engine is utilized to change the speed of the engine and the vacuum level is varied in proportion to changes in the pressure of fluid in said zone.

Abstract: A method and apparatus for controlling the liquid pumping rate of an internal combustion engine driven pump taking suction from a surge tank whereby a substantially constant level of liquid is maintained within the surge tank. The vacuum produced by the internal combustion engine is utilized to change the speed of the engine and the vacuum level is varied in proportion to changes in the level of liquid in the surge tank.

Abstract: A hydraulic motor comprising a cylinder, a stepped piston reciprocatable in said cylinder and having relatively proportioned leading and trailing surfaces, the surfaces together with axially directed surfaces defining, with the cylinder walls, first, second and intermediate cylinder zones, which intermediate cylinder zone is sealed with respect the first zone, valve controlled inlet and outlet of said cylinder in communication with said first zone, a water inlet of said cylinder in communication with the intermediate zone, piston wall portions defining a cylindrical recess opening out into the second zone and passages serving to effect communication between the recess and the second and intermediate zones, a tubular spool valve rod, apertured adjacent one end thereof and formed adjacent an opposite end thereof with a pair of axially spaced apart flanges fitting slidingly into the cylindrical recess, the rod having formed thereon an outwardly directed abutment located intermediate the flanges and the one end o

Abstract: An automatic pump speed controller for controlling and maintaining the strokes per minute of a down-hole oil well pump and providing signals on the surface indicating the actual strokes per minute of the pump. The automatic pump speed controller comprises a means for measuring the strokes per minute of the pump, and a means for adjusting the pump to correspond to a preselected stroke per minute value. The automatic pump speed controller also provides for a visual read out of the actual strokes per minute of the pump which enables an observer to obtain this information. In the present invention, pressure pulses from the pump are transmitted to the invented automatic pump controller on the surface and are monitored. If the pulses indicate that the pump is operating at a rate different than the preselected rate, the controller is adapted to automatically readjust the pump to conform to the preselected rate.

Abstract: This is a method and apparatus for controlling a downhole, hydraulically actuated pump. Two fluid flow monitoring means generate signals which are a function of the power fluid flow rate to the downhole pump and the return fluid flow rate from the well. An automatic controller causes the power fluid flow rate to be maintained essentially directly proportional to the return flow. Thus, the power fluid flow is not varied in the opposite direction of any change in return flow to maintain the return fluid flow constant, but conversely, is changed in a manner which will tend to accentuate any changes in the return fluid flow.

Abstract: A blood pumping system has a pair of integral flexible bodies each provided with an inlet and an outlet and disposed in open top cavities in a housing. The cavities have extensions holding inlet valves and outlet valves for opening and closing the inlets and outlets. A flexible diaphragm overlies the cavities and their extensions and is secured by a cover providing separate chambers over the inlet valves, the outlet valves and the bodies. Solenoid air valves are selectively energized to supply and exhaust the chambers to operate the valves and bodies. Switches responsive to the full and empty positions of the bodies govern the energization of the solenoids through control circuitry including a voltage controlled oscillator, a device for changing the frequency of the oscillator in accordance with the time of operation of at least some of the switches, and a device for ensuring at least a minimum rate of operation of the switches.

Abstract: This invention relates to a fluid actuated paint pump for high pressure airless spray guns and includes a novel unloading system in combination with a self-reversing fluid motor connected to a double-acting pump which supplies paint from a reservoir to an airless spray gun at a pressure which may run as high as 3500 psi.

Abstract: An intensifier unit includes a pair of sequentially operated reciprocating ram assemblies, each powered by a cylinder motor. Extension of the cylinder rods is accomplished by application of pressurized hydraulic fluid to the pistons. The pistons are returned quicker than they are extended by means of continuous application of pressurized air to the back side of the pistons. The cylinder motors are precompressed prior to their respective forward strokes by means of an accumulator which continuously bleeds from the main hydraulic fluid supply line. Circuitry is provided to insure that precompression continues even if the ram and its driving piston move from their retracted position. Also disclosed is a safety interlock to shut down the intensifier if both cylinder rods become accidentally simultaneously extended.

Abstract: The invention discloses a self-controlled, portable gas compressor which lizes a low pressure air source to compress a high pressure air source in a single stage booster compressor pump which is automatically shut down by an air pilot switch when a predetermined pressure is reached.