Abstract: A scroll compressor for use in compressing gases includes a stationary scroll member having a top surface, a movable scroll member orbiting about the stationary scroll member for compressing gases together with the stationary scroll member as it orbits about the stationary scroll member, a discharge port formed in the center of the stationary scroll member for discharging the compressed gases, a plurality of release ports which are offset different distances from the center of the stationary scroll member, a release cavity formed in the stationary scroll member and in communication with one of the plurality release ports, a release guide passage passing through the stationary scroll member in parallel with the top surface of the stationary scroll member in communication with the release cavity, a sealed case for housing the stationary scroll member and the movable scroll member and a release pipe connected to the release guide passage through the sealed case.

Abstract: The invention relates to a pressure actuated lift valve in a rotary screw machine mounted in one of the end walls of the machine, e.g. for the purpose of controlling the built-in volume ratio of the machine. The valve contains a cylindrical valve member 11 displaceable in an axial boring 13 and an actuating piston 12 in a cylinder 14. The boring 13 extends between the working space 24 of the machine and said cylinder 14. Through channels 20, 21, 22 pressure fluid is supplied to the cylinder 14 whereby the actuating piston 12 affects the valve member 11 to take an open or a closed position.By making the actuating means as a unit separate from the valve member 11 the manufacture is facilitated.

Abstract: A pressure relief valve for positive pressure pump systems in which fluid is displaced from the inlet to the outlet of the pump. The pressure relief valve includes a bypass tubing member interconnecting the outlet and a lower pressure area such as the inlet. Pressure limiting means normally occlude the bypass tubing to restrict flow when the outlet pressure of the pump is below a predetermined level and responds to pressure above a predetermined level to shunt fluid from the outlet to the inlet. In the preferred embodiment, the pressure limiting means consists of bar-like members which engage the exterior of the tubing and are biased to compress the bypass tubing to a flow restricting position by elastic bands extending around the bar-like members.

Abstract: A compressor, e.g., a scroll type compressor for a heat pump including a bypass passage by way of which the high pressure side of the compressor is communicated with a compression chamber in which a compression stroke is carried out is disclosed. The compressor further includes opening/closing means so that when it is required that the compressor is operated at a high efficiency, the bypass passage is closed and when it is required that the compressor is operated with a high level of ability, the bypass passage is opened so as to allow high pressure gas to be introduced into the compression chamber in which a compression stroke is carried out whereby the gas is compressed again.

Abstract: A fuel pumping apparatus of the rotary distributor type is provided with a spill control muff on the distributor member and which controls flow of fuel from a bore containing the pumping plungers to a chamber. Slidable in the chamber is a spring loaded piston formed with a valve element which controls flow of fuel from the bore into the chamber through a spill passage. With the spill passage closed by the valve element deliver of fuel through an outlet takes place until fuel is admitted to the chamber under the control of the spill muff. The admission of fuel causing the piston to move the valve element to allow fuel into the spill passage through the spill passage.

Abstract: A fuel pumping apparatus of the rotary distributor type includes a spill passage 20 connected with the bore 12 which houses the pumping plungers 9. A seating 22 is defined about the spill passage and a valve member 23 is provided for cooperating with the seating. A piston 25 is coupled to the valve member and is slidable in a cylinder. The piston defines a surface against which fuel under pressure from the bore 12 can act to lift the valve member from the seating. The application of fuel under pressure to the surface of the piston is controlled by an electro-magnetically operable control valve 32A.

Abstract: A fuel pumping apparatus has a pumping plunger operable by a cam to deliver fuel to an outlet. A spill valve is provided which when open permits fuel to spill from the bore in which the pumping plunger is located. An actuating piston is located in a first cylinder and is coupled to the spill valve and a storage piston is located in a second cylinder connected to the first cylinder. A control valve controls the pressure in the first cylinder and when the pressure is raised the actuating piston lifts the spill valve from the seating and the fuel from the bore can flow into the first cylinder and when the actuating piston is displaced therefrom, into the second cylinder.

Abstract: A gerotor structures is disclosed having a fluid bypass means for selectively siphoning off the high pressure fluid from the expanding gerotor cells so as to disable the operation of the device.

Abstract: There is disclosed herein a small and compact vacuum pump which serves as a portable vacuum source. The pump basically includes a cylinder coupled with a handle, and a piston in the cylinder coupled with another handle, along with a suitable valving assembly for allowing a vacuum to be drawn at an inlet of the pump. More particularly, there is also disclosed a vacuum release which can be attached to or form an integral part of the pump. The vacuum release comprises a closure member which can be moved upwardly and downwardly in a housing to close and open with respect to a valve seat and, respectively, allow a vacuum to be pulled or release the vacuum. The closure member is arranged to rotate and is biased by a suitable helical torsion spring to normally maintain the closure member in the closed position to therefore normally allow a vacuum to be drawn by the pump.

Abstract: A variable displacement, rotary fluid pressure pump (11) is disclosed of the type having a cam ring member (25) which is movable, in response to rotation of a control shaft (35), between a neutral position (FIG. 5) and a displaced position (FIG. 4). The pump housing (13, 15) includes a support member (25), and they cooperate to define a high-pressure fluid passage (51). In communication with the passage (51) is a recess (71), in which is disposed a dampening shoe (73). The dampening shoe is biased by high-pressure fluid in the passage (51) into engagement with an adjacent surface (77) of the cam ring (25). The surface (77) defines a neutral fluid passage (79), and the dampening shoe (73) defines a restricted opening (85).

Abstract: A small and compact vacuum-pressure pump which serves as a portable vacuum-pressure source is disclosed. The pump includes a cylinder coupled with one handle and a piston therein coupled with another handle. A valving means with a rotatable in a cylinder allows either a vacuum or pressure to be created at a port to the valving means. The valving means which is located ahead of an inlet valve to the cylinder can adapt a preexisting vacuum pump to operate either as a vacuum pump or a pressure pump as required.

Abstract: A scroll type compressor with a variable displacement mechanism is disclosed and includes a housing having an inlet port and an outlet port. A fixed scroll is fixedly disposed within the housing and has a first circular end plate from which a first spiral element extends. An orbiting scroll includes a second spiral element interfitting with the spiral element. The first circular end plate partitions an inner chamber of the compressor housing into a front suction chamber linked to the inlet port, and a rear chamber. The rear chamber is further divided by a wall of said housing into a discharge chamber linked to the fluid outlet port and an intermediate pressure chamber. At least one pair of holes is formed through the circular end plate of the fixed scroll forming a fluid channel between fluid pockets formed between the spiral elements of the scrolls and the intermediate pressure chamber.

Abstract: For controlling the internal volume of a rotary compressor (5), adjustable valve bodies (3) are used on the outlet side. External control means, often of an extremely complicated nature, have previously been used to control the internal volume in the rotary compressor. By allowing the different pressure levels of the rotary compressor (5) to directly influence a control section (1), the position of the valve body (3) can be controlled by an operating section (2). In the control section (1) an intermediate pressure (9) from the compressor is balanced against a pressure from the high-pressure side (19) of the compressor by a plunger (6) having different diameters. The position of the plunger (6) then determines the control of the internal volume by the position of the valve body (3) connected to the operating section (2).

Abstract: A method for producing selectively controlled pressure pulses in a mass of gas, particularly contained in a space of large dimensions. To achieve a sufficiently high power in the pulses, the pulses are generated by a valveless displacement machine in which the pressure when the machine opens towards its outlet port differs from the pressure of the mass of gas. The pulse is generated as the working fluid, due to said pressure difference, flows at high velocity through the outlet port. An acoustic power of the generated pulses of up to 20 kW can be attained by the method. The invention also concerns a rotary displacement machine for performing the method.

Abstract: A hydraulic single piston pump for manual operation has a piston (3) with a first channel (14, 20) running from piston chamber (7) to the rod chamber (5). The first channel has a check valve (15-19) opening in the return stroke. The piston (3) also has at least one second channel (22, 23, 25) running from the piston chamber (7) to the rod chamber (5). The second channel is configured as a choke bore (23, 25) along at least a part of its length.

Abstract: A motor/pump includes a cylindrically shaped rotor journaled within a similarly shaped housing to define an annular fluid passageway therebetween. The annular passageway is divided into a plurality of discrete fluid chambers by mobile blocking members which are mounted on the rotor near its periphery and stationary blocking members which extend outwardly from the housing to block fluid passage. Both types of blocking members are preferably free to rotate in place. Fluid inlets and outlets positioned around the annular chamber alternately pressurize and depressurize the chambers formed by the blocking members. The stationary blocking members are coupled to the rotor for synchronous rotation to allow passage of the mobile blocking members thereby. One preferred embodiment includes dampeners in the fluid inlets and outlets so that rotation of motor/pump can be controlled to provide the desired motor/pump characteristics.

Abstract: A wellpoint pumping system having a frame and a positive displacement rotary pump for pumping air, water or a mixture thereof mounted on the frame. The pump has two rotors with intermeshing lobes mounted on horizontal and parallel shafts, an inlet port below the rotors and an outlet port above the rotors. A motor for driving the rotors is mounted on the frame and a coupler connects the motor to the rotors. A closed inlet reservoir is formed in the frame below the pump, and an outlet reservoir is mounted on the frame at a level above the inlet reservoir. A conduit depends from the pump inlet port into the inlet reservoir and terminates close to the bottom of the inlet reservoir and a conduit connects the outlet port of the pump with the outlet reservoir.

Abstract: In a compressor of the type in which there is a movable trapped volume such as a screw or scroll type of compressor the trapped volume moves into and out of fluid contact with one or more valves. The valve(s) can provide fluid communication between the trapped volume and either suction for unloading or discharge for V.sub.i control.

Abstract: A scroll-type compressor has a stationary scroll and a moving scroll which is orbitted about the center of the stationary scroll. A valve chamber, a first by-pass, and a second by-pass are formed in the end plate of the stationary scroll. The first by-pass communicates between the inside of the valve chamber and one of the compression chambers formed by the scrolls, and the second by-pass communicates between the inside of the valve chamber and the outside of the end plate of the stationary scroll. The valve chamber houses a plate-shaped valve which is moved by fluid pressure between a closed position, in which it blocks the by-passes, and an open position, in which working fluid can flow between the two by-passes. Working fluid at either discharge pressure or suction pressure can be introduced into the valve chamber to the rear of the valve through a connecting pipe which is connected to the valve chamber and a 3-way solenoid valve.

Abstract: An aquarium filter having a housing unit for mounting on the wall of the aquarium tank with an intake chamber for receiving contaminated water and a filtering chamber for filtering the contaminated water and passing it back into the aquarium. A removable intake tube transfers the water from an inlet end to an outlet end where it can flow from the aquarium tank to the intake chamber. A slidable control valve selectively exposes bypass ports on the outlet end to regulate the flow rate of the aquarium water from a maximum down to shut-off, and all values therebetween.

Abstract: A fluid pump system whose output can be varied by converting it from maximum output to a lesser output and in between by dumping or varying one of its pumping elements or pistons to the inlet side of the pump. More specifically, a pump is provided with two opposed pistons, both of which are connected to inlet and outlet for maximum capacity. The piston chamber of one piston is equipped with a converter line for leading that chamber back to the inlet, whereby only the remaining piston furnishes the pump discharge. Variations in the adjustable mode of the valve is reflected in the action of the pump relief valve to cause increased effectiveness of a jetter line supplied by the pump output.

Abstract: A rotary compressor comprises an input shaft, a compressor component and a clutch component movable between an engaged position where the compressor component is connected to the input shaft to allow a torque to be transmitted from the input shaft to the compressor component and a disengaged position where the compressor component is disconnected from the input shaft to prevent the torque from being transmitted from the input shaft to the compressor component. A hydraulic pump is drivingly connected to the input shaft to discharge a pressurized working fluid upon the rotation of the input shaft. The clutch component includes a clutch member disposed within a clutch cylinder and cooperating therewith to define a pressure chamber.

Abstract: A device for controlling a rotating-piston machine in which inner and outer rotors rotate at unequal speeds and profiled teeth thereon form gaps to define working chambers which move, with change of volume, from an inlet region to an outlet region of the machine. The device comprises a body having a feed channel for a working fluid, a plurality of supply channels which open into the inlet region and two rotary slide valves for controlling communication between the feed channel and the supply channels to fill the working chambers during development of suction therein upon rotation of the rotors. The body has two round cutouts each containing a respective rotary slide valve. One slide valve controls supply of fluid at the beginning of development of suction in each working chamber whereas the other slide valve controls supply fluid at the end of development of suction in each working chamber. Each cut-out is connected to the feed channel and to respective associated pluralities of supply channels.

Abstract: A small and compact vacuum pump which serves as a postable vacuum source is disclosed. The pump includes a cylinder coupled with one handle and a piston therein coupled with another handle, along with a wafer valve assembly for allowing a vacuum to be drawn at an inlet of the pump. A previous version of the pump is improved upon by the use of different valve assemblies, to produce a more reliable, more easily assembled and less expensive vacuum pump. A vacuum release mechanism is provided operable with a finger of the hand about the handle.

Abstract: A screw compressor for intermittent operation, preferably for supplying a pneumatic brake system of an automotive vehicle with compressed air, comprises, in the high pressure end wall (4) of the compressor, a wall plate (14) which seals against the casing wall (2) of the compressor and which can be withdrawn axially of the compressor out of sealing engagement with the casing wall and into a space (16) which is provided in the high pressure end wall, the space (16) communicating with the compressor inlet (12), to thereby fully unload the compressor.

Abstract: An ink pump system includes an ink reservoir and an ink solvent reservoir from which solvent is controllably transferred into the ink in the reservoir so as to maintain the desired ink viscosity. The ink reservoir has an ink outlet for discharging ink to a point of consumption and an inlet into which excess ink may be recirculated to the ink reservoir. A seal-less gear pump is submerged in the ink reservoir. The pump includes a housing with an inlet communicating with the interior of the ink reservoir so as to receive ink from the ink contents in the reservoir. The pump housing also has a discharge outlet communicating with the ink outlet of the reservoir. The power source for drawing the recirculating gear pump can also be used to drive a paddle which stirs the ink in the reservoir.

Abstract: A small and compact vacuum-pressure pump which serves as a portable vacuum-pressure source is disclosed. The pump includes a cylinder coupled with one handle and a piston therein coupled with another handle. A valving means with a rotatable in a cylinder allows either a vacuum or pressure to be created at a port to the valving means. The valving means which is located ahead of an inlet valve to the cylinder can adapt a preexisting vacuum pump to operate either as a vacuum pump or a pressure pump as required.

Abstract: The present disclosure is directed to a water/air pumping system comprising essentially a substantially flat primary reservoir, a header tank and a pump. At least one reciprocating piston is powered through the tank. Eccentric drive cams are directly connected to the motor driven shaft and are connected to drive the pistons to pump water or air from the reservoir into the tank. A water and or air supply connection is horizontally connected to the reservoir and is provided with a water/air control valve proximate the reservoir. A tank discharge connector is connected to a water or air service system through the side wall of the tank externally thereof, above the motor driven shaft and its direct drive connection with the pistons for lubricating the driving mechanism. An air inlet valve is situated in the external wall of the primary reservoir beneath the piston intake so that the pump may pump either air or water.

Abstract: A pumping apparatus is formed by a flexible, metal wall structure surrounding and defining a hollow interior chamber and with a mechanism to compress and expand the structure to create a pumping action through an opening to the chamber. The pumping apparatus forms part of an overall system particularly adapted for pumping abrasive liquids.

Abstract: A variable displacement type compressor is disclosed. The compressor includes a housing having fluid inlet and fluid outlet ports. A fixed scroll is fixed within the housing and has a circular end plate from which a first spiral element extends. The end plate of the fixed scroll partitions the inner chamber of the compressor housing into a front chamber connected to the fluid inlet port and a rear chamber. The rear chamber is divided into a discharge chamber connected to the fluid outlet port and an intermediate pressure chamber. The end plate of the fixed scroll has at least two holes which connect the fluid pockets to the intermediate pressure chamber. The end plate also has a communicating channel which connects the front chamber to the intermediate chamber. A control device controls the communication between the front chamber and intermediate pressure chamber.

Abstract: An air compressor having a pair of coacting rotors, useful as a supercharger for an engine, has a throttle plate in the compressed-air discharge port of its airend. The plate is carried by a shaft which is journalled in the airend housing. An air bypass channel is formed in the housing, The channel being in communication with the air-end air inlet. A pair of apertures formed in the housing open onto both the channel and the rotors, and flapper valves, pivotably mounted in the channel, monitor the apertures. Spring steel limbs, fixed to the throttle plate shaft engage and disengage the valves, to close and open the apertures, respectively, as the shaft is rotated to open and close the compressed-air discharge port, respectively again, by means of the throttle plate.

Abstract: A pumping system employing a main pump and a high pressure centrifugal pump both of which are driven by an engine through a suitable drive is provided with an air clutch device whereby air is selectively introduced into the inlet of the high pressure centrifugal pump to cause air binding of the impellers, this action causing a de-clutching of the high pressure pump by a simple hydraulic action.

Abstract: A method and several embodiments of apparatus are disclosed for modulating the capacity of a gas compressor. A discharge valve member is formed with an opening therein and fluid communication between the compression chamber and a clearance pocket is selectively established by a slidable plunger element. In a first position, the plunger fills the opening in the discharge valve member to close fluid communication between the clearance pocket and the compression chamber. In a second position, the plunger element moves away from the valve member to establish fluid communication between the compression chamber and the clearance pocket, wherein the reexpansion volume is increased and the capacity of the compressor reduced. In the preferred embodiment, an apertured neck member is provided. The valve member is slidably guided by outer walls of the neck member, and the plunger has a stem designed to slidingly fit within the neck aperture.

Abstract: A pressure-operated valve is provided, particularly for use with a downhole pump of the fluid-driven, successive-stage, bladder type. Such a pump includes a plurality of pump and transfer modules. The pump modules have bladders which are operated by fluid, preferably gas, under pressure supplied through two separate internal passages in the modules to pump liquid upwardly through transfer modules. The pressure-operated valve is located below the bottom of the pump module and normally closes off the two gas passages. When gas under pressure above operating pressure is supplied through one of the passages, to establish a sufficient pressure differential between the passages, the valve opens to connect the passages. Heated gas can then be circulated to increase the temperature of internal oil passages extending through the modules to prevent paraffin formation. The two gas circuits can also be connected to enable removal of condensate.

Abstract: A housing assembly for a hydraulic pump unit utilized in motor vehicles wherein a housing body is deep drawn from a circular blank of a typically high strength, low alloy steel. A drawn elongate valve sleeve is attached to the housing body by a stamped saddle member. The valve sleeve, saddle member, and housing body are produced with appropriate fluid passages and ports for the flow of hydraulic fluid through the housing assembly.

Abstract: A motor-driven regenerative type fuel pump is provided with an overflow mechanism disposed adjacent to a discharge pipe. The overflow mechanism includes a plug hole in a pump housing and a plug member disposed in the plug hole. The pump housing is formed with an axially inclined recess circumferentially extending around the plug member and communciated with an axial groove formed in the plug member. The rate of overflow of fuel and thus the upper limit of the pump discharge can be adjusted by rotating the plug member relative to the plug hole to compensate for any insufficiency of pressure regulating ability of a pressure regulator in an engine fuel injection system. The overflow mechanism further includes an adjustment-locking member attached to the pump housing and the plug member after the overflow-adjustment by the manufacture has been completed.

Abstract: A rotary screw gas compressor for a refrigeration system comprises a motor-driven single main rotor having helical grooves and mounted for rotation in a rotor bore in the compressor housing and a pair of star-shaped gate rotors rotatably mounted in the housing and engageable with the helical grooves to define a plurality of compression chambers. A suction slide valve member is slidably positionable (between full load and unload positions) to control where low pressure uncompressed refrigerant gas from a suction port is admitted to the compression chambers to thereby function as a suction bypass to control compressor capacity. A discharge slide valve member is slidably positionable (between minimum and adjusted volume ratio positions) to control where high pressure compressed refrigerant gas is expelled from the compression chambers to a discharge port to thereby control the volume ratio and thereby the input power to the compressor.

Abstract: A rotary screw gas compressor for a refrigeration system comprises a motor-driven single main rotor having helical grooves and mounted for rotation in a rotor bore in the compressor housing and a pair of star-shaped gate rotors rotatably mounted in the housing and engageable with the helical grooves to define a plurality of compression chambers. A suction slide valve member is slidably positionable (between full load and unload positions) to control where low pressure uncompressed refrigerant gas from a suction port is admitted to the compression chambers to thereby function as a suction bypass to control compressor capacity. A discharge slide valve member is slidably positionable (between minimum and adjusted volume ratio positions) to control where high pressure compressed refrigerant gas is expelled from the compression chambers to a discharge port to thereby control the volume ratio and thereby the input power to the compressor.

Abstract: A fuel pumping apparatus for supplying fuel to an internal combustion engine includes a valve means operable to control the spillage of fuel from a high pressure pump. The valve means includes first and second valve elements connected by a pivotal beam carried on a pivot movable in the direction of valve closure when an actuator is energized. The first valve element is biased by a spring to the open position and through the beam the second valve element is held in the closed position by the pressure developed by the pump and the second valve element is urged to the open position by the pressure but can be held closed against the pressure by the actuator. When the actuator is de-energized the second valve element is urged open by the pressure to lower the pressure and the spring then opens the first valve element and closes the second valve element.

Abstract: Disclosed herein is a two-stage fluid pump comprising a base member defining a sump, a first fluid pumping unit including a pumping piston and supply and discharge passages, a second fluid pumping unit including a pumping piston and supply and discharge passages, a plate member fixed on the sump and having mounted thereon the first and second fluid pumping units, the plate member including a conduit communicating with the first unit discharge passage and with the second unit supply passage and a discharge conduit communicating with the second unit discharge passage and terminating in a discharge port in the plate member, a drive engaged with the pistons for effecting reciprocation thereof and including an electric motor mounted on the plate member and including an output shaft, a drive member mounted on the plate member for rotation and having an eccentric portion drivingly connected with the pistons to effect reciprocation thereof in response to rotation of the drive member, and a speed reducing mechanism op

Abstract: The invention concerns the combination of electric motor, diaphragm air pump, valving and switches in a compact form to provide a low pressure air supply and control system for use in inflating and/or deflating air chambers in seats. The air chambers may be so placed as to provide support to areas of the back of an occupant, support to the occupant's thighs, either singly or both at the same inflation/deflation and/or movement of the side bolsters of the seat. Additionally, it may be used to inflate/deflate the seat bottom.

Abstract: A hand held device for regulating and monitoring air pressure. The device comprises an elongate barrel having a crown end and an opposite end attachment structure for connecting the device to a point of use such as an inflatable endotracheal cuff. A plunger pump in the barrel is digitally operable at the crown end for generating air pressure within a chamber the in barrel. A pressure monitoring gauge is carried by the barrel. Air pressure generated by the plunger pump communicates from the chamber through the attachment structure with the point of use, and through a mercury reservoir with the pressure monitoring gauge. A second digitally operable plunger carried by the barrel and engageable at the crown end is adapted for selectively releasing the air pressure from the chamber.

Abstract: A screw pump of the kind including a screw array consisting of a central screw (1) with convex flanks and one or more side screws (2) with concave flanks, the threads being formed such that coacting screws seal against each other with the screw array being sealingly surrounded by a screw housing (3), so that at least one closed chamber is formed by the sides and roots of the threads as well as the screw housing, the chamber migrating axially from the inlet end of the screw array to its outlet end when the screws are turned, and is in communication at least during a portion of its migration with a pressure fluid source (9) via at least one duct (14) made in the pump. To prevent the occurrence of, and to eliminate, existing air and gas bubbles in the liquid chamber without efficiency being unnecessarily deteriorated, the pump is provided with a regulating device (15) coacting with the duct for adjusting the quantity of liquid flowing to the chamber from the pressure fluid source.

Abstract: A slide valve type screw compressor having a slide valve with a surface of chevron shape in section consisting of a couple of arcuately curved surfaces forming part of the inner wall surfaces of a rotor chamber accommodating a pair of intermeshed male and female screws, the slide valve being slidable in the axial direction of the rotors for communicating the rotor chamber with a suction port through an opening with an adjustably variable area for volumetric control of the compressor, characterized in that the slide valve is retractably protruded into a suction casing at a fore end on the side of the suction port and has the opposite outer corner portions of the curved surfaces cut off at a predetermined angle with the longitudinal axis thereof to provide a substantially triangular section with a forwardly reduced width at the protruded fore end.

Abstract: An improved hand-operated vacuum pump is disclosed and includes a cylinder, head assembly, and elastic seal member. The cylinder and head assembly define opposing grooves, and the elastic seal member is positioned in the grooves to secure the head assembly to the cylinder. A piston assembly is operative within the cylinder to draw a vacuum within the head assembly.

Abstract: A device for controlling the volumetric capacity of a screw compressor having two rotors, which are in meshing engagement with each other, in a compression chamber enclosed in a housing, in which there is also arranged a bore in parallel with the rotors, the bore being connected to the compression chamber through a number of channels distributed axially in the bore, a plunger being arranged to be movably guided in the bore as volume control is effected. Depending on the position of the plunger in the bore, the number of the channels covered thereby varies. The plunger is hollow and has an opening at one end through which a rod fixed in the bore passes, the rod carrying a piston sealingly engaging the inside surface of the plunger. At its other end, the plunger is closed by an end wall. The position of the plunger in the bore is adjusted by the supply of a control medium, such as oil, which influences both sides of the end wall. Any volatile refrigerant, such as R.sub.22 or R.sub.

Abstract: A tube pump for use in pumping a liquid from one place, such as a tank, to another, such as a vessel, the tube pump comprising a first tube for sucking a liquid from a tank; a second tube for allowing the sucked liquid to discharge therethrough; a connecting chamber located in the joint of the first and the second tube, where these two tubes are communicated with each other; a bellows member communicating with the connecting chamber, the bellows member being adapted to be gripped by the user's hand; the bellows member having an opening closable by a valve member; the valve member including a cap having an aperture in its center, and a cover including a stem slidably passed through the aperture, wherein the aperture is airtightly closed by the stem when no force acts on the cover but is opened when the cover is pushed downwards.

Abstract: An air pump apparatus having a cylinder extending from a pump casing. The cylinder comprises a cylinder liner positioned within the walls of the cylinder and a piston is mounted for reciprocating movement within the cylinder liner. The pump chamber is formed between the front of the piston and the front portion of the cylinder wherein an annular gap is formed between the piston and the inner wall of the cylinder liner, wherein the piston has a plurality of annular grooves formed on the outer circumferential surface thereof, the annular gap and annular grooves forming a labyrinth path extending from the pump chamber.

Abstract: A rotary pump for pumping liquid which includes a rotor combination in the form of a vane pump or gear and rotor with pumping chambers disposed circumferentially around the rotor. The chambers progressively increase in the inlet area and ensmall in the outlet area. Resilient means are interposed between the ensmalling chambers and an outlet to block backflow of the pressurized outlet liquid into pumping chambers containing vaporized liquid instead of solid liquid, thus reducing the pump noise under conditions of vaporization termed "cavitation".

Abstract: A flushable, positive displacement, gear-type metering pump assembly comprising: a pump housing with inlet and outlet chambers; cylindrical gears disposed within the pump housing adapted to rotate such that gear faces mesh and form a seal which separates inlet and outlet chambers, the gears being adapted to carry metered amounts of fluid between the gear faces and the wall of the pump housing from the inlet chamber to the outlet chamber; channel means for conveying fluid into the inlet chamber and directing the fluid against the gear faces exposed to the inlet chamber; channel means for conveying fluid from the inlet chamber to valve means; channel means for conveying fluid from the valve means to the outlet chamber; valve means adapted to be closed when the pump assembly is in a metering mode such that fluid may pass from the inlet chamber to the outlet chamber only by being carried between the gear faces and the wall of the pump housing and in an open mode when the pump is in a flushing mode such that fluid