Abstract: A self contained mechanical bleed control apparatus for a fluid conveying system, such as a central vacuum system or a pressurized air system, includes a slide member housing which slidably supports an orifice plate having an air foil on one end disposed within a main flow conduit just upstream from a vacuum producer or downstream from the compressor in a pressurized fluid system. A source of bleed fluid communicates with the slide member housing and is valved by movement of the orifice plate. The orifice plate is biased to a position for communication of bleed fluid into the main conduit under low flow conditions. Increased flow through the main conduit acts on the air foil to slide the orifice plate against the urging of the biasing force to cut off the bleed fluid supply.

Abstract: Inlet passages and two sets of discharge passages are communicated with a pair of pump chambrs formed in a pump cartridge in a pump body. A pair of spool valves respectively acting as a flow quantity control valve and a pressure sensitive type flow path switchng valve are formed in parallel in the pump body in directions perpendicular to the axis of the pump.

Abstract: A pump with a continuous inflow and a pulsating outflow comprises a first chamber and a second chamber with a passage between them and made at least partly from a flexible material. There is an inlet to the first chamber and an outlet from the second chamber. The passage between the chambers has a one-way valve permitting flow only in a direction from the first to the second chamber. A second one-way valve located at the outlet permits flow only in a direction out of the second chamber. The chambers are movably supported in a pump casing having a first and a second opening. The inlet is connected to and penetrates the first opening, and the outlet is connected to and penetrates the second opening. A drive arrangement reduces the volume of the second chamber to expel the pumped medium while simultaneously enabling the walls of the first chamber to increase the volume and permit the pumped medium to flow through the inlet into the first chamber.

Abstract: A seal and retainer assembly for an air compressor piston includes a cup-shaped seal with its marginal edge extending at an angle relative to the cylinder wall, the seal having a notch extending circumferentially at the base of its marginal edge defining a hinge which allows pivoting of the marginal edge relative to the main body portion of the seal which is clamped to the piston. A head plate includes an air intake port for communicating the compression chamber with an air inlet and a discharge port for communicating the compression chamber with a compressed air discharge outlet, each of the ports having a flexible spring closure member cooperating with an inclined valve seat to allow the ports to be open whenever the compressor is shut off.

Abstract: A valve assembly for controlling discharge of hydraulic fluid from a high pressure hydraulic fluid container to a hydraulic fluid reservoir and including a valve body having a valve bore, a fluid inlet port communicating with the valve bore on one side of a valve seat, and a fluid outlet port communicating with the valve bore on an opposite side of the valve seat. A valve spool is housed in the valve bore and includes a valve member selectively engageable with the valve seat to prevent hydraulic fluid flow through the valve bore. The valve member is selectively biased against the valve seat by a valve piston housed in a valve cylinder, the valve piston being operably connected to the valve member such that hydraulic fluid pressure in the valve cylinder biases the valve member toward the valve seat.

Abstract: A method is disclosed for operating a large motor-driven refrigeration gas compressor which has independently movable suction and discharge slide valves to prevent undesirable, possibly damaging hydraulic pressure build-up caused by sealing oil remaining in the gas compression chambers during compressor start-up. While the compressor is started and brought up to full speed, the suction slide valve is disposed in fully unloaded position to fully open the gas suction port and the discharge slide valve is disposed in position to fully open the gas discharge port to enable excess oil in the gas compression chambers to exit freely through the compressor gas discharge port before oil pressure build-up can occur. When the compressor is at full speed, the suction slide valve is positioned to maintain a desired gas suction pressure and the discharge slide valve is positioned to equalize gas pressure between the gas compression chambers and the compressor gas discharge port.

Abstract: A communication hole is bored through a partition member which divides an intake-side priming fluid chamber from a discharge-side priming fluid chamber, whereby the two chambers are connected. The communication hole serves to prevent, on a predetermined level, a backflow of a pump fluid due to siphonage caused on the intake side when pumping operation is stopped, thereby securing a priming fluid in a pump casing. A valve assembly including a valve member is disposed corresponding to the communication hole. The valve member, which is always urged to an open position, is moved to and held in a position where it is caused to close the communication hole by the action of the pump fluid flowing in a feeding direction during pumping operation. When the pump is stopped to cause the backflow of the fluid, the valve member is moved back to the open position by the urging action.

Abstract: A hermetically sealed rotary refrigerant compressor, comprising a compression chamber, a roller eccentrically rotatable in the chamber, and a vane slidably mounted in a slot in the wall of the chamber dividing the chamber between a low pressure suction side and a high pressure compression side including means for modulating the pressure differential between the low pressure suction side and the high pressure compression side of the vane at a preselected time in the compression cycle so as to minimize the frictional forces between the vane and vane slot caused by the pressure differential in the chamber.

Abstract: A scroll type compressor is disclosed which includes a housing with an inner chamber and fluid inlet and outlet ports connected to the inner chamber. A fixed scroll, which is mounted within the housing, has a circular end plate from which a first spiral wrap extends. An orbiting scroll also is mounted within the housing for orbital motion with respect to the fixed scroll. The orbiting scroll has a circular end plate from which a second spiral wrap extends; the first and second wraps interfit to define at least one pair of sealed off fluid pockets. The end plate of the fixed scroll partitions the inner chamber of the housing into a suction chamber and rear chamber. The rear chamber is divided into a discharge chamber and an intermediate pressure chamber. The circular end plate of the fixed scroll has at least one pair of holes symmetrically positioned to connect the sealed off fluid pockets to the intermediate pressure chamber.

Abstract: A minimum flow valve device includes a housing providing a liquid passageway therethrough having an inlet end and an outlet end; a guide element mounted in the liquid passageway which provides an internal chamber that is open towards the inlet end of the liquid passageway, the guide element including a discharge orifice communicating with the internal chamber; an unloading pipe extending through the housing and communicating with the discharge orifice; an annular non-return valve element; and a valve sleeve member connected to the non-return valve element and extending within the internal chamber. The valve sleeve member includes orifices such that when the non-return valve element and the valve sleeve member are positioned to block liquid flow through the liquid passageway, liquid will flow through the discharge orifice and out the unloading pipe.

Abstract: A lifting device for controlling the movement of the closure plate of a compressor valve comprises a first gripper part which is connected to the compressor valve to be movable toward and away therefrom; a regulating spring which is in contact with the first gripper part to bias it toward the compressor valve; and a second gripper part which is movable with respect to the first gripper part and the compressor valve, the second gripper part including lift elements having lifting prongs which can contact the closure plate, tension screws which connect the lift elements to the first gripper part and provide end stops for the movement of the lift elements, and damper springs which damp the relative movement of the lift elements relative to the first gripper part.

Abstract: A vane type rotary pump comprises a cam ring mounted within a stator housing and having an inner peripheral wall defining four circumferentially equi-spaced semicylindrical inner cam surfaces, a pair of end wall structures fitted to opposite ends of the cam ring to form a pump cavity, a drive shaft rotatably mounted within the stator housing, a rotor contained within the pump cavity and mounted on the drive shaft for rotation therewith, and a plurality of circumferentially equi-spaced vanes slidably fitted in the body of the rotor to cooperate with the inner cam surfaces to form four pairs of suction and delivery chambers.

Abstract: A gas compressor has cylinders in which gas is compressed by pistons. Each cylinder has a suction valve and an exhaust valve to admit uncompressed gas and expel compressed gas. The suction valve includes a suction valve plate which repeatedly moves toward and away from the top end of the cylinder between closed and open positions, respectively. Apparatus to control compressor capacity includes an unloader mechanism to selectively prevent the suction valve plate moving to fully closed position to thereby unload the cylinder and reduce compressor capacity. The unloader mechanism comprises an unloader piston movable in an unloader cylinder in response to system conditions to move a linkage which determines the closure position of the suction valve plate. The linkage includes a pivotable lift arm biased toward a position which allows full closure of the suction valve plate and is movable by the unloader piston to another position which prevents full closure of the suction valve plate.

Abstract: The invention relates to a venting device for oil-burning installations. A float arranged in a venting chamber controls both a connection between the venting chamber and the surrounding atmosphere and a connection between the venting chamber and the suction side of an oil pump included in the installation.

Abstract: A rotary compressor for compressing a refrigerant gas has a by-pass port and a control valve means. The by-pass port communicates at one end with a suction chamber containing the gas to be compressed, and at the other end with a compression chamber wherein compression of the refrigerant gas is in progress. The control valve means includes a valve spool accommodated in a chamber formed in a front side plate of the compressor and movable between its full-load position, where a gas suction port is opened to the compression chamber while the by-pass port is closed, and its partial-load position where the former is at least partially closed while the latter is opened. The valve spool is normally biased to its partial-load position. During operation of the compressor, the valve spool is placed under the influence of a first pressure of the gas acting to urge the same towards its said full-load position, and to a second pressure of the gas to urge the same towards its said partial-load position.

Abstract: The compression capacity of a rotary compressor may be changed by a cylinder bypass system. The change of compression capacity is achieved by a slide wall member which composes part of an inside wall of a cylinder containing a compression mechanism and which is movable, thereby bypassing gas being compressed to a suction side of the compressor. The slide wall member is caused to slide forward by gas pressure applied and to slide backward by a spring force. By controlling such gas pressure, the capacity of the compressor may be changed. A relatively large opening is formed in the cylinder when the slide wall member is moved backward, so that the compression capacity can be greatly reduced without a large decrease in efficiency.

Abstract: A compressor bypass passage has an inlet portion and an outlet portion which is connected to the suction passage. The inlet portion of the bypass passage has an opening which is able to be open to the compression chamber when the compression chamber is in a decreasing volume stroke, thereby to spill the refrigerant from the compression chamber into the suction passage. A control pressure chamber is formed in the housing. A valve member is arranged in the inlet portion of the bypass passage. The valve member is actuated in response to a variety of pressures of the refrigerant in the control pressure chamber for adjusting the area of the opening of the inlet portion of the bypass passage. A pressure supply passage for supplying a refrigerant, which pressure is higher than the pressure in the suction passage, is connected to the control pressure chamber. A spill passage for spilling a part of the refrigerant interconnects the control pressure chamber to the suction passage.

Abstract: A capability control apparatus for a compressor wherein gas sucked into a compression chamber is compressed due to a decrease in volume of the compression chamber. The pressure of the gas sucked into the compression chamber, in response to an increase or decrease in load, is automatically controlled by varying the volume of the compression chamber based on the pressure of the sucked gas.

Abstract: An oil pump assembly comprises a pump body assembly composed of a pair of front and rear pump bodies, the rear pump body housing in a pump housing space a pair of pumps each including a pump cartridge having a rotor supported on a common drive shaft rotatably supported on the front pump body, and a cam ring accommodating the rotor. A single side plate is axially slidably interposed between the pump cartridges. A pressure plate is disposed between one of the pump cartridges remote from the front pump body and a pump discharge pressure chamber defined at the bottom of the pump housing space and communicating with a main passage through which one of the pumps communicates with a discharge port. The other pump is selectively connected by a directional control valve to the main passage. The pump and valve parts can easily be assembled into the pump bodies, and hence the oil pump assembly can be mass-produced efficiently, less costly, and is small in size and lightweight.

Abstract: An oil-sealed vacuum pump comprises an oil circuit for supplying a pump chamber and bearings of the vacuum pump with oil. The oil circuit includes first and second branch conduits leading to the bearings and the pump chamber, respectively. The vacuum pump further has an oil pump coupled to the oil circuit for driving oil therethrough, a valve assembly coupled to the oil circuit for shutting off oil supply to the pump chamber during standstill of the vacuum pump, and a pressure reducer coupled to the oil circuit for reducing the oil pressure to environmental pressure. The first branch conduit leading to the bearings is situated upstream of, and the second branch conduit leading to the pump chamber and the valve assembly are situated downstream of the pressure reducer as viewed in the direction of oil flow in the oil circuit.

Abstract: A refrigerating cycle apparatus has a compressor, a condenser, an evaporator, and a capillary tube. The condenser includes a compressor main body for compressing a refrigerant delivered therein, a valve hole, a groove for connecting the valve hole and a suction port of the compressor main body, a pipe for connecting the valve hole and a delivery port of the compressor main body, an aperture for connecting the valve hole and a suction port of the condenser, and a valve plug movably mounted in the valve hole. The valve plug is adapted to move between a first position where the pipe communicates with the aperture through the valve hole in accordance with a difference in pressure at the suction port and delivery port of the compressor when the compressor is in operation and a second position where the pipe does not communicate with the aperture through the valve hole when said compressor is stopped.

Abstract: The invention relates to a valve arrangement for capacity control of an oil-injected screw compressor. One or more piston valves are arranged one after the other in the axial direction of the rotors at the portion of the rotor barrels where the internal compression phase occurs. The compressor control valves are actuated by the discharge pressure, which in their turn open or close the piston valves. When the piston valves are open, a portion of the gas in the compression space is discharged to a bleed off passageway and it flows back to the inlet port of the compressor so that substantially no compression work is spent on this portion of the gas.

Abstract: An improved pump assembly is used to supply fuel to an aircraft engine and includes a positive displacement pump which supplies fuel during low speed operation of the pump assembly and a centrifugal pump which supplies fuel during relatively high speed operation of the pump assembly. The positive displacement pump has a plurality of vanes connected with an impeller of the centrifugal pump. The vanes are forced radially inwardly against a stationary cam surface by fluid pressure. The fluid pressure is conducted from an outlet of the positive displacement pump through a passage in the impeller of the centrifugal pump to pressure chambers disposed at outer ends of the vanes. By providing the fluid pressure passage in the impeller of the centrifugal pump, the axial length of the pump assembly tends to be minimized. The positive displacement pump is rendered ineffective to pump fluid when the output pressure from the centrifugal pump equals the output pressure from the positive displacement pump.

Abstract: A vacuum pump comprises a suction nipple valve including a cylinder, a piston slidably received therein and a movable valve closing member operatively connected to the piston. The vacuum pump further has a pressure medium conduit having a first end communicating with the cylinder; an inlet opening at a second end of the conduit for pressure medium to flow through the inlet opening to the piston; a control arrangement for closing and opening the inlet opening dependent upon run or standstill of the vacuum pump. In the closed state of the inlet opening an oil quantity is maintained above the inlet opening.

Abstract: A hydraulic power steering system has a vane type pump which is operable to supply fluid to a power steering gear at a volumetric rate determined in part by the system pressure requirement or system demand. The pump flow is partially bypassed through an aperture in the cam ring at low system pressures. The bypass flow is controlled by a sleeve valve surrounding the cam ring and being subjected to system pressure to incrementally close the aperture and reduce bypass flow and simultaneously increase the output flow. At a predetermined system pressure, the valve is moved sufficiently to control reopening of the aperture for controlled bypass flow to limit the maximum system pressure.

Abstract: An automobile air conditioner unit is provided with a compressor equipped with a number of compression chambers. At the start of air conditioner operation, less than all of these compression chambers are operated to avoid liquid compression. After start up, the number of compression chambers in operation will depend upon the air conditioning load, with a fewer number of chambers being operable at times when the load is low, as during temperature maintainance, as opposed to initial cool-down.

Abstract: In an oil pump having two pump cartridges each acting as independent pumps, a pair of suction passages and a pair of discharge passages opened in a pair of pump chambers in the pump cartridges are formed in one pump body secured to one side of the cartridges, a flow control valve is contained in an opening extending in an axial direction of the pump body, and a pressure sensitive flow passage change over valve is contained in another valve opening perpendicular to the valve opening. The two valve openings are communicated with the discharge and suction openings.

Abstract: A combined unloading valve and check valve (10) for use with a motor driven air compressor. The unloading valve (16) includes a spool (30) axially movable within a tubular body (12). In the unloading position of the valve, one of two spaced-apart ring seals (32) on the spool is out of engagement with the body to open a flowpath from the inlet of the valve past the spool to exhaust ports (28) formed in the body. When the compressor is operating and the valve is pressurized, both ring seals engage the body to close off the flowpath. The check valve (18) extends beyond the end of the body and includes a poppet valve element (50) which engages a valve seat (52) formed on an end of the spool. When the unloading valve and check valve is installed in a wall (14) of an air tank the check valve extends into the air supply within the tank, thereby helping to cool the internal elements of the valve structure.

Abstract: A hydraulic power steering system has a vane type pump which is operable to supply fluid to a steering gear at a volumetric rate determined in part by the system pressure or the system demand. The vane pump flow is partially bypassed through a valve member disposed in the end cover and thrust plate of the pump. The valve is rotatably disposed in the end cover and spring loaded therein to a position which permits direct fluid communication between the pumping chambers and the pump inlet. The valve member has a portion thereof operated on by system pressure which is operable to close the bypass passages with increasing system pressure such that pump discharge flow to the power steering system will increase. The valve member can be moved sufficiently in response to system pressure to reopen the bypass passages thereby providing a limiting value for maximum system pressure.

Abstract: A hydraulic power steering system has a vane type pump which is operable to supply fluid to a power steering gear at a volumetric rate determined in part by the system pressure or system demand. The pump flow is partially bypassed through a valve member which is slidably disposed in the thrust plate of the pump. The thrust plate has a bypass aperture which communicates between the pump discharge and the pump inlet. The valve member is spring loaded to permit fluid communication through the apertures and is pressure biased by increasing system pressure to reduce the bypass flow and thereby increase system discharge flow.

Abstract: A hydraulic power steering system has a vane type pump which is operable to supply fluid to a steering gear at a volumetric rate determined in part by the system pressure or system demand. The pump flow is partially bypassed through a valve member disposed in the cam ring at a position adjacent the pumping chambers. The valve is spring loaded radially inward to permit the bypass flow at low system pressure levels. Increasing system pressure levels bias the valve member radially outward thereby reducing bypass flow while simultaneously increasing pump discharge flow. At a predetermined pressure level, the valve member will reach a secondary opening position to bypass fluid flow and thereby limit the maximum system pressure.

Abstract: A hydraulic power steering system has a vane type pump which is operable to supply fluid to a power steering gear at a volumetric rate determined in part by the system pressure or system demand. The flow from the pumping chambers is partially bypassed through a bypass passage formed between the cam ring and the pump thrust plate. The bypass passage is urged to the open position by a bypass spring which urges separation between the cam ring and the thrust plate. The pressure plate of the pump responds to system pressure or demand to urge the cam ring into abutment with the thrust plate thereby reducing the opening and decreasing the bypass flow.

Abstract: A pressure control valve is provided for controlling both the low and high pressure ranges of a variable displacement pump in addition to the pressure control valve used for adjusting the variable displacement member of the variable displacement pump.

Abstract: A method and apparatus for sequence control of vertical movement of slurried particulates from a lower level to the upper levels, more particularly a vertical hoist system for movement of slurry from a subterranean mine area upward through an earthen or cased borehole to a surface station. The vertical pump system includes series-connected pumps having variable speed capability to transport slurry particulate from an underground sump upward to a surface surge tank or other repository. The logic sequence system exercises control over valving sequence between the underground pumps and the vertical borehole in order to control slurry surges during start-up, shut-down and emergency dump operations. Thus, the pump input to the vertical conduit utilizes energy dissipator units as selectively controlled by automated block and by-pass valves to control flow of fluids from the pumps upward through the vertical conduit.

Abstract: The present invention relates to a double-acting hydraulic pump comprising a piston moving with a reciprocal rectilinear movement inside a cylinder of which each chamber is provided with a suction valve and a delivery valve, the rod of said piston being adapted to be driven by a variable-displacement driving member. The said piston rod extends beyond the piston and moves, outside the cylinder within a space of variable volume, provided in the body of the pump, which communicates, with a member controlling the by-pass device through which the two chambers of the cylinder communicate.

Abstract: A rotary compressor formed with an unloading port maintaining a working space in communication with a suction chamber and opened and closed by a valve, to vary the capacity of the compressor. The internal pressure of the working space is sensed in a compression stroke or this pressure and the pressure of a fluid drawn by suction are both sensed, so as to open and close the valve based on the sensed internal pressure of the working space or the pressure differential between the internal pressure of the working space and the pressure of the fluid drawn by suction, to give suitable hysteresis to the operation characteristics of the on-off valve to stabilize the operation of the on-off valve.

Abstract: A flow path switching valve is provided, operating to merge hydraulic fluid from a plurality of pumps in accordance with a magnitude of a loading applied to a hydraulic unit, and a variable orifice is defined adjacent to the valve. A flow control valve is also provided for returning part of the hydraulic fluid to a tank, and operates in accordance with the throttle opening of the variable orifice which changes in accordance with the operation of the flow path switching valve.

Abstract: The invention relates to a motor driven reciprocating piston compressor of the type utilized for encapsulated small refrigerators. Valving for the valve plate between the piston and cylinder chamber provides automatic unloading when the gas in the cylinder chamber falls below a predetermined temperature in the 80 to 100 degree centigrade range to prevent pressure build ups in the cylinder chamber during idle periods which cause undesired high starting torques.

Abstract: This liquid flow control apparatus is a delayed closure valve mechanism intended for use in an unloading bypass between the outlet and the inlet of a pump for supplying fuel to an oil burner. The valve mechanism includes a conduit having a large diameter section between two small diameter sections. A ball valve having a diameter smaller than the large diameter section and larger than the two small diameter sections is captured within the large diameter section. The large diameter section extends upwardly, so that the ball is biased by gravity to its inlet end. When the pump starts, the ball is moved by the discharge pressure of the pump until it engages the upper end of the large diameter section, whereupon the unloading bypass is closed and the discharge pressure of the pump is effective to open a cut-off valve leading to the nozzle of the oil burner. The length of the large diameter section determines the time delay between the starting of the pump and the delivery of oil to the nozzle of the burner.

Abstract: An electric pump assembly (1) for lifting fluids in wells comprises a plurality of electric pumps (20) and (24) located at axially spaced apart locations in the well each pump having an axial aperture (21) to permit wire line operations to be conducted in the well below the assembly (1). Adjacent pumps (20) and (24) can rotate in opposite directions about a common axis to effect torque balancing. Each pump (20) can have a transformer (50) to permit local adjustment of voltage and means (40) are provided for sequential operation of the pumps. Assembly can be supported on cable (12), (14) or on production tubing (60) assisted by packers.

Abstract: To supply hydraulic fluid to a hydraulic apparatus, a plurality of pumps are used. One of the pumps is used as a main pump while the remaining pump or pumps are used as sub-pumps. A flow path switching mechanism selectively disconnects the sub-pumps from a supply passage to the hydraulic apparatus. In this manner, a required minimum supply of hydraulic fluid is assured with a simple arrangement while eliminating wasteful energy loss and reducing the dissipation of the horsepower. A reliable operation is maintained without any adverse influence upon the hydraulic apparatus. In one embodiment, a pair of pumps, and a control including a pair of switching valves operating as a pressure sensor and a flow controller are assembled into a pump body. The switching valves assure a reasonable supply of hydraulic fluid to the hydraulic apparatus while minimizing the dissipation of the horsepower.

Abstract: An automatic air venting device including a venting cylinder communicating with the pressure side of an electromagnetic plunger pump down-stream of a discharge valve thereof, a valved plunger fitted in the venting cylinder for sliding reciprocatory movement, a valve mounted at an end of the valved plunger on the side of a return port, a valve seat located at the return port and adapted to be engaged by the valve when the internal pressure of the pump is above a predetermined value during operation of the pump, a spring urging the valve to be brought out of engagement with the valve seat, and a leak passage formed in the valved plunger for bringing the pressure side of the pump into communication with the return port when the valved plunger is urged by the spring to move in a direction in which the valve is brought out of engagement with the valve seat.

Abstract: A solenoid-operated pump for discharging fluid from a tank through a fluid discharge passage in a pump body has a directional control valve disposed in the fluid discharge passage. The directional control valve is normally urged to direct fluid flow through a fluid drainage passage branched from the fluid discharge passage and adapted for connection to the tank. The fluid drainage passage includes a restrictor which produces a fluid-pressure build-up in response to a change in viscosity of the fluid flowing therethrough, that is, when air is no longer contained in the fluid. The directional control valve is responsive to such pressure build-up to direct the fluid to flow through the fluid discharge passage.

Abstract: A stepping piston is projected into the path of a slide valve drive piston to limit piston movement and thus the slide valve towards maximum unload position determined by piston bottoming out against the cylinder wall. The slide valve main drive piston stroke is also correlated to desired slide valve positions along the intermeshed helical screw rotors of the helical screw rotary compressor to provide, for example, stepped unloading at compressor full load, two-thirds full load, and one-third full load.

Abstract: An unloader for a high pressure hydraulic system, as a high pressure spraying system, has a pressure inlet for connection with a pump, a pressure outlet for connection with a load and a bypass outlet with a bypass valve. A piston moves the bypass valve between open and closed positions. The flow of liquid through the unloader from the inlet to the pressure outlet and to the hydraulic load establishes a pressure differential across the piston to close the bypass valve. When no flow to the load occurs, there is no differential pressure across the piston and the bypass valve is opened.

Abstract: A compressor unloader system and method is disclosed, comprising a pneumatically controlled one-way valve member for controlling communication between an unloader chamber and a compression chamber of a compressor.The one-way valve member has one surface exposed to the pressure of the unloader chamber. To close it a control mechanism is actuated to present a lower pressure to an opposing second surface, interior of the valve member, creating a pressure differential to urge the one-way valve member toward a closed position.Temporary excesses of compression chamber pressures relative to unloader chamber pressures may bump the valve open to charge the unloader chamber with essentially maximum compression chamber pressure, thereby neutralizing the effect of the unloader chamber and fully loading the compressor.The one-way valve member is biased toward an open position.

Abstract: A refrigeration system provided with a rotary compressor, a refrigeration pipe line system connected with the compressor and having a gas-liquid separator for separating an injection pressure gas refrigerant, and a gas injection channel extending from a gas zone of the separator and having an open-close valve. The compressor is provided at its cylinder block with an injection pressure port opening to a pumping chamber and with a valve chamber communicating with the port. A by-pass passage channel communicating with the suction port side of the chamber extends from the valve chamber, and a control valve having a communication aperture and a spring, are housed within the valve chamber, the injection channel is connected with a back chamber of the control valve within the valve chamber, so that the open-close valve may be operated to control a capacity of the refrigeration system.

Abstract: An unloader/check valve for use with an air compressor comprising a one-piece valve body, a valve member slidable in the body between open and closed positions, biased toward its closed position, the valve having a bleed for unloading the compressor when the valve member is in its closed position, and a dashpot arrangement for damping pulsations of the valve member.

Abstract: A hermetic compressor having an upper portion 12 and a lower portion 16 is provided with a motor 20 in its upper portion with a vertical crankshaft 22 extending down into the lower portion and driving a plurality of pistons 28, 30 in cylinders 24, 26 arranged radially around the crankshaft, each cylinder having a cylinder head 38 radially outwardly of the discharge valve 36, and at least the lowermost cylinder head 38 being provided with a spring-loaded drain valve 44 which opens upon the differential pressure between the inside of the cylinder head and the suction space in the compressor dropping below a given value during periods of non-operation of the compressor to drain an accumulation of liquids in the cylinder head.

Abstract: An air compressor has a low torque motor driven piston of the rocking rod type which operates in a cylinder with a closed head containing a discharge check valved port to a compressed air receiving chamber. The piston contains an intake port provided with a thin flexible metal spring closure strip which is inclined at a small angle to the valve seat about said intake port to open on the downstroke of the piston, close on the upstroke thereof and remain open when at rest to facilitate start and restart of the air compressor.