Abstract: A pressure controlling system for an inkjet printer includes a pressure chamber, a pump fluidically connected to the chamber and adapted for increasing or decreasing the pressure within the pressure chamber, a controllable three port two way valve, and a sensing unit including one or more pressure sensors. The pressure sensing unit is in fluidic communication with the pressure chamber for sensing the pressure therein. The valve has a first port controllably fluidically connectable to the pressure chamber, a second port controllably fluidically connectable to an inkjet print head, and a third port controllably fluidically connectable with atmospheric air. The sensing unit is adapted for sending signals representative of the pressure within the pressure chamber to at least one processor/controller. The pump and the valve are controlled by receiving control signals from the processor/controller(s). There are provided a method for operating the system and a printer including the system.

Abstract: A multi-stage positive displacement vacuum pump and a method of differentially pumping multiple vacuum chambers using such a pump is disclosed. The pump comprises a housing for housing at least one rotor mounted for rotation on a corresponding at least one shaft and for pumping gas through the multiple stages for output through an exhaust. The housing comprises a first inlet configured to admit gas to an inlet stage of said vacuum pump, and a further inlet configured to admit gas to an intermediate stage of said vacuum pump. The pump is configured such that gas admitted through each of the first and further inlets is pumped together as a combined gas flow by at least one stage of said vacuum pump downstream of said intermediate stage.

Abstract: A pump assembly is provided. The pump assembly includes a stator assembly and a piston assembly. The stator assembly includes a rotary winding and a linear winding. The piston assembly is positioned within the stator assembly. The piston assembly translates along a lengthwise axis of the stator assembly and rotates about the lengthwise axis of the stator assembly to create a pumping action.

Abstract: A rapidly modulated hydraulic supply is disclosed. The rapidly modulated hydraulic supply can include a chamber for receiving fluid. The rapidly modulated hydraulic supply can also include a displacement member operable to displace the fluid from the chamber. In addition, the rapidly modulated hydraulic supply can include a flow modulation system operable to vary the flow rate of the fluid output from the chamber. A first flow rate corresponds to a first output pressure, and is different from a second flow rate corresponding to a second output pressure for a like movement of the displacement member.

Abstract: A system includes first and second compressors arranged in parallel, a condenser, expansion device, evaporator, and flow control device fluidly connected. The first compressor includes a first lubricant sump and the second compressor including a second lubricant sump. A lubricant transfer conduit fluidly connects the first lubricant sump and the second lubricant sump. The flow control device is disposed between the evaporator and the first and second compressors, and includes a fluid inlet and two fluid outlets. A first of the two fluid outlets is fluidly connected to the first compressor, a second of the two fluid outlets is fluidly connected to the second compressor. The second fluid outlet includes a nozzle disposed within a flow passage of the flow control device such that a space is maintained between an outer surface of the nozzle and an inner surface of the flow passage.

Abstract: A flow cytometer system includes a flow cytometer, an autosampler and a system integration structure to accommodate interconnection and interface of the flow cytometer and autosampler for operation together and providing for convenient interface with equipment for handling process liquids.

Abstract: A vacuum pump comprises: a first pump stage; a second pump stage provided downstream of the first pump stage; a first suction port provided on a suction side of the first pump stage; and a second suction port provided downstream of the first pump stage and communicating with the second pump stage. The first pump stage includes a siegbahn pump portion suitable for a small exhaust volume, and a turbo-molecular pump portion. The second pump stage includes a Holweck pump portion suitable for a great exhaust volume.

Abstract: An air pump capable of automatic air supplements has a housing, a low-pressure blower, a high-pressure blower, a first auto-stop controller, and a second auto-stop controller. The low-pressure blower is used to inflate an inflatable article with low-pressure air and allows the air pump to stop working during inflation automatically. The high-pressure blower is used to inflate an inflatable article with adjustable high pressure air, so that the inflatable article can have a hardness suitable for a user's need, and allows the air pump to stop working automatically during inflation or to supply air automatically during inflation. The air pump can stop working automatically and can supply air automatically without manual work, and can inflate the inflatable article to the hardness suitable for the user's need conveniently.

Abstract: A charged particle beam device provided with: a charged particle optical lens column generating a primary charged particle beam; a housing which has its inside evacuated by a vacuum pump; a first diaphragm that forms a part of the housing and able to keep an airtight state of the interior space of the housing; and a second diaphragm disposed between the first diaphragm and the sample, wherein a primary charged particle beam generated by the charged particle optical lens column is transmitted by or passes through the first diaphragm and the second diaphragm, and then is irradiated, on the sample that is in contact with the second diaphragm.

Abstract: An air pump with internal automatic controller has a housing, and a low-pressure blower, a high-pressure blower, a first auto-stop controller and a second auto-stop controller mounted in the housing. The first auto-stop controller has a first casing, a first air pressure sensing film, a pushing element, a swing rod, a connecting rod, a rotation restricting element, a first micro switch, a rotational pressing rod, and a first turning button. With the low-pressure blower inflating an inflatable article with low pressure air, and with the first auto-stop controller stably and reliably controlling the low-pressure blower, the low-pressure blower stops working automatically. The first auto-stop controller has simplified structure and inflates the inflatable article without manual work, which is a great convenience to users.

Abstract: The present disclosure provides a fluid pump having a pump motor, a pump drive shaft and a vane pump assembly. The pump assembly includes a pump housing having fluid inlet and outlet ports. The pump assembly also includes a distal bearing member having first and second sides and a second side, a plurality of inlet orifices, and a cavity formed in the second side. A first cam ring, having an elliptical interior opening, is disposed within the pump housing adjacent the distal bearing member. A rotor is disposed within the opening in the first cam ring. This rotor has first and second sides, a cavity in the first side, and a plurality of radial slots for sliding vanes. The vane pump assembly also includes a second cam ring, having an elliptical shape, disposed in the cavities formed in the distal bearing member second side and the rotor first side.

Abstract: Staged peristaltic pump systems and related methods are disclosed. A system may be configured such that the working fluid pressure differential across any individual stage of the system is smaller than the pressure across the entire system. In some embodiments certain components of each stage may be sealed from fluid communication with an external environment, though working fluid may be configured to cross the boundary of the seal. In some embodiments, stages may be pressurized with respect to an external environment.

Abstract: A method and a device for recycling compressed gas where the compressed gas used in a compressed gas consumer, particularly a container blow-molding machine, is fed back into a compressed gas generator. In order to increase the recycling volume, the compressed gas from the compressed gas consumer is collected separately and fed back to at least a first and a second pressure range of the pressure generator separately according to pressure stages.

Abstract: The invention relates to a vacuum pump or vacuum apparatus having a vacuum pump for the evacuation of one or a plurality of volumes, the vacuum pump having a plurality of pressure stages and at least two suction inlets. According to the invention, an outer suction inlet for a first pressure stage spatially encompasses an inner suction inlet for a second pressure stage such that the inner suction inlet seals only against pressure within the outer suction inlet, not against external pressure.

Abstract: A differentially pumped vacuum system includes first, second and third chambers, and a pumping arrangement for evacuating the chambers. The pumping arrangement includes a compound pump having a first inlet connected to an outlet from the first chamber, a second inlet connected to an outlet from the second chamber, a first pumping section and a second pumping section downstream from the first pumping section, the sections being arranged such that fluid entering the compound pump from the first inlet passes through the first and second pumping sections and fluid entering the compound pump from the second inlet passes through, of said sections, only the second section. The pumping arrangement further includes a booster pump connected to an outlet from the third chamber, and a backing pump connected to the exhaust from the booster pump. Fluid exhaust from the compound pump can be conveyed to either the booster pump or the backing pump as required.

Abstract: A differentially pumped mass spectrometer system comprises a mass spectrometer having first and second pressure chambers through which, during use, ions are conveyed along a path. A pump assembly for differentially evacuating the chambers is attached to the mass spectrometer. The pump assembly comprises a housing attached to the mass spectrometer and a cartridge inserted into the housing. The cartridge has a plurality of inlets each for receiving fluid from a respective pressure chamber and a pumping mechanism for differentially pumping fluid from the chambers. The cartridge is inserted into the housing such that the pumping mechanism is inclined relative to the ion path, but with the cartridge protruding into the mass spectrometer to such an extent that at least one of the inlets at least partially protrudes into its respective chamber without crossing the ion path.

Abstract: A vacuum pump for the evacuation of one or a plurality of volumes is described. The vacuum pump has a plurality of pressure stages and at least two suction inlets. An outer suction inlet for a first pressure stage spatially encompasses an inner suction inlet for a second pressure stage such that the inner suction inlet seals only against pressure within the outer suction inlet, not against external pressure.

Abstract: An oil supply system of an automatic transmission includes a first oil pump pumping up oil from the oil reservoir and supplying the oil to the low-pressure part, a low-pressure regulating valve connected to a low-pressure part channel connecting the first oil pump with the low-pressure part, and controlling the pressure of the oil discharged from the first oil pump at pressure required by the low-pressure part, a second oil pump receiving the oil of which the pressure is controlled through the low-pressure regulating valve and supplying the oil to the high-pressure part, and a high-pressure regulating valve connected to a high-pressure part channel connecting the second oil pump with the high-pressure part and controlling the pressure of the oil discharged from the second oil pump at pressure required by the high-pressure part.

Abstract: A compressor system includes a compressor for supplying compressed air to a commercial vehicle that has an engine with a turbocharger. Air that is pre-compressed by the turbocharger can be sucked in by the compressor via a first air supply pipe. Ambient air that is not pre-compressed can be sucked in by the compressor via a second air supply pipe. A method operates the compressor system including the compressor for supplying the compressed air to the commercial vehicle that has the engine with the turbocharger accordingly.

Abstract: A differentially pumped vacuum system includes first, second and third chambers, and a pumping arrangement for evacuating the chambers. The pumping arrangement includes a compound pump having a first inlet connected to an outlet from the first chamber, a second inlet connected to an outlet from the second chamber, a first pumping section and a second pumping section downstream from the first pumping section, the sections being arranged such that fluid entering the compound pump from the first inlet passes through the first and second pumping sections and fluid entering the compound pump from the second inlet passes through, of said sections, only the second section. The pumping arrangement further includes a booster pump connected to an outlet from the third chamber, and a backing pump connected to the exhaust from the booster pump. Fluid exhaust from the compound pump can be conveyed to either the booster pump or the backing pump as required.

Abstract: A noise reducing device for a hermetic type compressor is provided that includes a plurality of cylinders disposed at upper and lower portions thereof, a communication path that provides for communication between inlets of the plurality of cylinders, and a suction pipe coupled to an inlet of one of the plurality of cylinders. Such an arrangement may reduce a number of components and simplify the fabrication process. Accordingly, fabrication costs may be reduced, and vibration due to resonation of a plurality of suction pipes may be avoided. Further, such an arrangement may provide enhanced performance by optimizing a specification of the suction pipe and a suction path thereof.

Abstract: A multi-stage compressor is provided that reliably prevents liquid compression in a higher stage compression mechanism and also prevents compression efficiency degradation resulting from overheating of injection refrigerant and from the lubricating oil being raised up together with the injection refrigerant. An injection circuit is branched into a plurality of circuits. A first circuit thereof is communicatively connected to an inside space of a closed housing that is at the same side as the higher stage compression mechanism with respect to an electric motor, and a second circuit is communicatively connected to an inside space of the closed housing that is opposite from the higher stage compression mechanism with respect to the electric motor. The first circuit and the second circuit are provided with a switching mechanism for switching the injection circuit to the first circuit or the second circuit according to the dryness of the injection refrigerant.

Abstract: A fluid channeling device including a channeling body, an axial transfer channel, and a radial outlet channel. The channeling body includes first and second annular body sections spaced axially apart and a tubular body section extending between the first and second body sections. The axial transfer channel is defined axially through the channeling body, and is configured to fluidly couple a first compression assembly with a second compression assembly. The radial outlet channel is defined radially through the channeling body and is configured to fluidly couple the second compression assembly with an outlet.

Abstract: A casing assembly for a compressor includes an internal compression assembly with a shaft and at least one impeller disposed on the shaft. The casing assembly includes an inlet body segment having a fluid inlet, an outlet body segment having a fluid outlet, and a number of intermediate body segments selected from a plurality of intermediate body segments, which are preferably preformed. The intermediate segments are disposed between the inlet and outlet segments to form the casing and each has an inner circumferential surface defining an interior chamber section, the chamber sections collectively defining at least a portion of a compressor chamber sized to receive the compression assembly. Preferably, the intermediate segment inner surfaces have equal inside diameters and are generally coaxially aligned. As such, the inner surfaces collectively define a portion of continuous compressor support surface of a desired axial length for supporting the compression assembly.

Abstract: A differentially pumped system comprises a plurality of pressure chambers; and a pumping arrangement (100) attached thereto for evacuating the chambers, the pumping arrangement comprising first and second compound pumps (102, 104) each comprising at least a first inlet (120); (124), a second inlet (122); (126), a first pumping section (110) and a second pumping section (112) downstream from the first pumping section, the sections being arranged such that fluid entering the pump from the first inlet passes through the first and second pumping sections and fluid entering the pump from the second inlet passes through, of said sections, only the second section, wherein the first inlet (120) of the first pump (102) is attached to an outlet from a first, relatively low, pressure chamber (10), the second inlet (122) of the first pump (102) and the first inlet (124) of the second pump (104) are attached to an outlet or respective outlets from a second, common medium pressure chamber (16), and the second inlet (126) o

Abstract: A differentially pumped mass spectrometer system comprises a mass spectrometer having first and second pressure chambers through which, during use, ions are conveyed along a path. A pump assembly (10) for differentially evacuating the chambers (62, 66, 68) is attached to the mass spectrometer. The pump assembly comprises a housing (12) attached to the mass spectrometer and a cartridge (14) inserted into the housing. The cartridge has a plurality of inlets (16, 18, 20) each for receiving fluid from a respective pressure chamber (62, 68, 66) and a pumping mechanism (30, 32, 34) for differentially pumping fluid from the chambers. The cartridge is inserted into the housing such that the pumping mechanism (10) is inclined relative to the ion path (76), but with the cartridge protruding into the mass spectrometer to such an extent that at least one of the inlets (16, 18) at least partially protrudes into its respective chamber (62, 68) without crossing the ion path.

Abstract: A heat pump system is disclosed that utilizes an accumulator fluidly connected between a boost compressor output and a primary compressor input. The accumulator is multifunctional in that it allows the refrigerant from the boost compressor to be cooled with refrigerant from other parts of the system if necessary. The accumulator also serves to receive and cool the oil separated from the refrigerant near the output of the primary compressor. A method for distributing oil among the compressors is also disclosed.

Abstract: A fluid channeling device including a channeling body, an axial transfer channel, and a radial outlet channel. The channeling body includes first and second annular body sections spaced axially apart and a tubular body section extending between the first and second body sections. The axial transfer channel is defined axially through the channeling body, and is configured to fluidly couple a first compression assembly with a second compression assembly. The radial outlet channel is defined radially through the channeling body and is configured to fluidly couple the second compression assembly with an outlet.

Abstract: A multi-stage compressor is provided that reliably prevents liquid compression in a higher stage compression mechanism and also prevents compression efficiency degradation resulting from overheating of injection refrigerant and from the lubricating oil being raised up together with the injection refrigerant. An injection circuit is branched into a plurality of circuits. A first circuit thereof is communicatively connected to an inside space of a closed housing that is at the same side as the higher stage compression mechanism with respect to an electric motor, and a second circuit is communicatively connected to an inside space of the closed housing that is opposite from the higher stage compression mechanism with respect to the electric motor. The first circuit and the second circuit are provided with a switching mechanism for switching the injection circuit to the first circuit or the second circuit according to the dryness of the injection refrigerant.

Abstract: Provided is a liquid chromatograph pump system which sucks eluent from an eluent reserving container, and which feeds pressurized high pressure eluent into a column, wherein a plunger reciprocating in a cylinder is formed on its outer peripheral surface with a stepped part along the sliding direction of the plunger in the cylinder so as to define a working chamber between the stepper part and the inner wall surface of the cylinder, the flow rate of the liquid chromatograph pump being determined by the volume of the working chamber and the traveling speed of the plunger, thereby it is possible to stably feed a liquid at an extremely low flow rate, and to satisfactorily expel air bubbles upon a start of the liquid chromatograph pump system.

Abstract: A liquid hydrocarbon slug-containing vessel for incorporation into a system integrating a low-pressure separator with a vapor recovery process system, and a method for regulating the temperature of a gas to be compressed by a two stage compressor so as to prevent liquification of the gas and to prevent over-heating of the compressor.

Abstract: A turbo compressor is provided with a first compression stage that draws in and compresses a fluid, and a second compression stage connected to the first compression stage via a rotation shaft, that further compresses the compressed fluid from the first compression stage. The first compression stage and the second compression stage are arranged adjacent to each other with their backsides facing each other. A discharge port of the first compression stage, and a suction port of the second compression stage are formed in the same plane, and there is provided a U-shaped pipe that connects the first discharge port and the second suction port.

Abstract: A two-stage compression rotary compressor is provided that includes a low-stage compressing section and a high-stage compressing section housed within a cylindrical sealed housing oriented vertically, a low-stage suction pipe that is connected to a suction side of the low-stage compressing section and sucks in a low-pressure refrigerant, a low-stage discharge pipe the is connected to a discharge side of the low-stage compressing section and discharges the refrigerant from the low-stage to outside of the sealed housing, a high-stage suction pipe that is connected to a suction side of the high-stage compressing section and sucks in the refrigerant discharged from the low-stage, a low-pressure connecting pipe that connects the low-stage suction pipe and an accumulator, and guides the refrigerant inside the accumulator to a suction side of a low-stage compressing section, and an intermediate connecting pipe that connects the low-stage discharge pipe and the high-stage suction pipe, wherein an inner diameter of th

Abstract: A two-stage rotary compressor includes a sealed cylindrical compressor housing that includes first, second and third communication holes separately arranged sequentially in an axial direction on an outer peripheral wall, an accumulator held on an outer side of the housing, a low-pressure connecting pipe that connects a bottom communication hole of the accumulator and the second communication hole, and an intermediate connecting pipe that connects the first and third communication holes. The second and third communication holes are arranged at nearly the same circumferential direction position of the housing. The accumulator is held at nearly the same circumferential direction position as the second communication hole.

Abstract: A diaphragm pump for pumping a fluid includes a housing, a pump chamber defined in the housing, a first diaphragm for sealing the pump chamber, a pressure control chamber defined in the housing adjacent to the pump chamber via the first diaphragm, a second diaphragm for sealing the pressure control chamber, a drive mechanism operable to deform the first and second diaphragms, an introduction passage for introducing into the pressure control chamber a part of the fluid that is discharged from the pump chamber, and a pressure regulating valve disposed in the introduction passage for adjusting a pressure in the pressure control chamber to a medium pressure between a suction pressure and a discharge pressure.

Abstract: A hydraulic system includes a charge pump which supplies fluid to variable displacement main pump, a fluid reservoir and valve unit. The valve unit includes a hollow housing having a first end communicated with the reservoir and a second end communicated with the charge pump and the main pump. A housing valve land member is located between the first and second ends. A valve member is movably mounted in the housing. The valve member has a valve disk attached to first and second valve stems which project from opposite sides of the valve disk. The valve disk has a central position wherein the valve disk is received by the ring. The valve stems are slidably supported by stem support members at opposite ends of the housing. A hollow sleeve projects from an end of the valve unit. A spring is mounted in the sleeve and is engagable with an end of one of the valve stems and is biased to urge the valve member away from the sleeve.

Abstract: A rotary liquefied natural gas boil-off compressor has a series of compression stages. A gas passage passes through the series of compression stages. The gas passage extends through and is in heat exchange relationship with cooling means in the form of indirect heat exchangers. Each of the heat exchangers is cooled by LNG supplied from a pipeline. Flow control valves are provided for controlling the flow of LNG to the heat exchangers respectively. The valves are controlled in response to temperature sensors respectively, so as to maintain the inlet temperature of each of the compression stages at a chosen sub-ambient temperature or between chosen sub-ambient temperature limits.

Abstract: A multi-stage reciprocating vacuum pump includes first (2) and second (4) pump chambers located in the pump housing (1) and in which respective pistons (6, 8) reciprocate, first and second conduits (14, 20) for communicating, respectively outlet and suction (15, 16) sides of the first pump chamber (2) with the suction side (17) of the second pump chamber (4), and shut-off elements (18, 21; 25) associated with the first and second conduits (14, 20) for selectively communicating the first and second conduits (14, 20) with the suction side (17) of the second pump chamber (4); and the method of operating the pump includes manipulating the shut-off elements so that the first and second conduits (14, 20) are selectively connected to the suction side (17) of the second pump chamber (4).

Abstract: A multi-chamber installation (1) treats objects under vacuum. An evacuation system (5) is connected to a plurality of chambers (2, 3, 4). To reduce the complexity of the evacuation process, a forepump (5) has several stages (11, 12, 13). Each of said stages is connected to one of the chambers (2, 3, 4).

Abstract: A two-stage compressor for generating necessary pressure differential for air-conditioning applications with air-cooled, water-cooled and evaporative-cooled condensing systems using low-pressure refrigerant, such as R134a, is provided. A rotating assembly is mounted for rotation in a compressor housing and includes a shaft, a thrust bearing disk associated with the shaft to maintain an axial position of the rotating assembly, a motor rotor mounted on the shaft, and first and second impellers mounted for rotation with the shaft. First and second journal bearings are mounted in the compressor housing to support the shaft and maintain radial positioning of the rotating assembly. Volute housings including a spiral-shaped volute are associated with each of the impellers to collect and further discharge gas compressed by the impellers. Diffusers having air-foil shaped vanes are locate in the volute channels adjacent the discharge outlets of the impellers to aide in the discharge of gas from the impellers.

Abstract: A hermetic two stage rotary compressor having a housing with a stationary shaft fixedly mounted in the housing. A motor having a rotor and a stator is mounted in the housing with the rotor being rotatably mounted on the shaft. A pair of compression mechanisms are rotatably mounted on the shaft with one compression mechanism being located adjacent a first end of the rotor, and one compression mechanism being located adjacent a second end of the rotor. The compression mechanisms are operatively associated with the rotor such that rotation of the rotor drives the compression mechanisms. A fluid flow path is defined in the compressor including a plurality of longitudinal bores formed in the stationary shaft. A mounting assembly is attached to the housing so as to mount the compressor in either a substantially horizontal or vertical orientation. The pump is positioned so as to be at least partially immersed in an oil sump in the housing when the compressor in either orientation.

Abstract: A multi-stage compression type rotary compressor, having a driving element and a first and a second rotary compression element that are driven by the driving element in a sealed container, is provided. The refrigerant compressed by the first rotary compression element is discharged into the sealed container, and said discharged refrigerant with an intermediate pressure is then compressed by the second rotary compression element. By cooling the refrigerant absorbed into the second rotary compression element, the rise in the temperature of the refrigerant that is compressed and discharged by the second rotary compression element can be suppressed. And, the supercooling degree of the refrigerant is increases before reaching the expansion valve to improve the cooling ability of the evaporator.

Abstract: A dry compressing vacuum pump (1) has a continuous or graduated inner compression. A gas ballast device (8) selectively adds a ballast gas to a pumped gas. The gas ballast device has an isolating valve (11), a non-return valve (12) which prevents the escape of gases from the pump through the gas ballast device to the outside, and a pressure differential valve (13).

Abstract: A cascade type pump arrangement for a particle beam device has first and second turbomolecular pumps, wherein an outlet of the second turbomolecular pump is forepumped by an intermediate pressure region situated between a main pump port and an outlet of the first turbomolecular pump. The particle beam device has a particle beam source operated in ultra high vacuum and a specimen chamber operated at pressures from high vacuum at least up to 1 hPa.

Abstract: A two-stage oil free compressor assembly includes a pressure modulation mechanism, which enhances the ambient temperature and altitude capability of the compressor. A selected amount of pressurized fluid is drawn from an output side of a second stage compressor portion and reintroduced into the lower pressure interstage circuit of the assembly, thus raising the interstage pressure. The fluid that flows through the pressure modulation mechanism can be further cooled using the interstage heat exchanger, depending on the needs of a particular situation. A valve in the pressure modulation mechanism is adjusted to control the amount of fluid utilized for pressure modulation. The inventive arrangement permits modulating the pressure ratio of each stage to achieve reasonably balanced discharge temperatures of the first and second stage.

Abstract: A two-stage oil free compressor assembly includes a pressure modulation mechanism, which enhances the ambient temperature and altitude capability of the compressor. A selected amount of pressurized fluid is drawn from an output side of a second stage compressor portion and reintroduced into the lower pressure interstage circuit of the assembly, thus raising the interstage pressure. The fluid that flows through the pressure modulation mechanism can be further cooled using the interstage heat exchanger, depending on the needs of a particular situation. A valve in the pressure modulation mechanism is adjusted to control the amount of fluid utilized for pressure modulation. The inventive arrangement permits modulating the pressure ratio of each stage to achieve reasonably balanced discharge temperatures of the first and second stage.

Abstract: A multi-stage liquid elevator which is assembled from individual stages is a fabricated from ordinary pipe components and has no moving parts. Each elevator stage consists of a reservoir defined by a casing enclosing an inlet pipe and an outlet pipe. A coupling connects any two stages of the elevator together. As many stages as required can be joined together to construct a multi-stage liquid elevator of any desired length. Each stage is fabricated to a length compatible with the available gas pressure. Enough pressure must be available to move a column of liquid a vertical distance equal to or greater than the length of one stage of the elevator.

Abstract: A multi-stage liquid elevator is assembled from individual stages in which each elevator stage is fabricated from ordinary pipe components and has no moving parts. When inserted into an natural gas well, the elevator is powered by the gas pressure available in the well. At each stage, the liquid and gas from the previous stage are forced into the inlet pipe and the liquid collects in the reservoir until enough gas pressure builds up in the stage to force the liquid up the outlet pipe to the next stage. The elevator requires only enough pressure from the well to move a column of liquid a vertical distance equal to or greater than the length of one stage of the elevator.

Abstract: A pumping system for selectively activating the stages of a multi-stage centrifugal pump is provided. The pumping system has a first stage impeller for receiving fluid into the system and imparting rotational energy into the fluid. The system also has a second stage impeller for centrifugally imparting additional rotational energy into the fluid after the first stage impeller. A valve selectively closes an inlet to the second stage impeller so that the system operates as a single stage centrifugal pump while the second stage impeller remains wetted.

Abstract: A vacuum pump comprising a shaft rotatable by means of a motor, at least two spaced pump stages mounted on the shaft, a first pump inlet through which gas can pass for passage through all the pump stages for evacuating a first system and a second pump inlet through which gas can enter the pump at an inter-stage location for passage through only subsequent stages of the pump for evacuating a second system, said first and second systems each having a gas outlet flange for attachment to a first or a second pump inlet, in which the vacuum pump is mounted relative to the respective first and second systems such that the longitudinal axis of the shaft is inclined to each of the gas outlet flanges.