Abstract: The invention comprises an arrangement for controlling the flow of a coolant fluid in a compressor, in particular in a rotary compressor, in which a coolant-fluid inlet for coolant fluid discharged from the compressor and a coolant-fluid outlet for returning the coolant fluid into the compressor are provided. A fluid cooler is also provided through which, when necessary, part of the coolant fluid can be directed for cooling and a system-control actuator is used to control the magnitude of the proportion of the coolant fluid that is directed through the fluid cooler on the basis of system parameters, in particular on the basis of the temperature of the coolant fluid.

Abstract: A dry vacuum pump assembly that includes a casting having an inner chamber, an inlet and an outlet communicating with the inner chamber, a pair of right and left handed screw rotors positioned in the casing, each screw rotor having a cross section formed by a Quimby curve, a circular arc, and a quasi-Archimedean spiral curve, the pair of screw rotors intermeshing with each other to pump a process gas pumped from the inlet to the outlet. The pump assembly further includes a nitrogen-supplying tube that communicates with the inner chamber at a position near the outlet in the casing, and an external pipe that connects the outlet to a scrubber or a trap which external pipe is straight and does not include a silencer.

Abstract: The present invention relates to a compressor (1) that has an associated coolant circulation system (1, 4, 6, 8, 11, 13), and also to a method of maintaining a low bacteria content in the coolant circulating system (1, 4, 6, 8, 11, 13), in which method gas and coolant are supplied to the compressor (1) during running of the system and the gas is compressed in the compressor (1) to an outlet pressure, the gas and the coolant are removed together from the compressor (1) and then separated into a respective gas and a liquid phase, whereafter the gas is passed to a recipient and the liquid is cooled before being returned to the compressor as coolant. The method is characterised by creating bacteria-killing conditions intermittently in the system by appropriating the heat-generating capacity of the compressor (1) to raise the temperature of the circulating coolant to at least 55° C. for a duration of at least 15 seconds.

Abstract: An air compressor assembly of the rotary screw type. The air compressor assembly comprises a housing having an inlet end and a discharge end. An internal working chamber extends within the housing and terminates in a discharge end face at the discharge end of the housing. At least one rotor is mounted for rotation and axial movement within the working chamber. The rotor has a discharge end surface having a step defined thereon. A thrust piston extends from the rotor and is positioned within a thrust piston chamber. A pressure source is associated with the thrust piston chamber and is controllable between a high pressure condition and a reduced pressure condition to control the position of the rotor relative to the discharge end face. A method of mounting a rotor with a desired end clearance is also provided.

Abstract: A gas rotary screw compressor (1), in particular, for cooling gas suitable for low-power systems, the compressor having a casing (1a) having an intake conduit (6) and a delivery conduit (7); and the casing (1a) having, internally, a three-dimensional region shaped to follow the outer profile of the helical teeth (11b) of a male rotor (11) and the helical teeth (12b) of a female rotor (12), so as to define a first intake chamber (45) to minimize the load losses of the gas stream and so fill the casing (1a) with a maximum quantity of gas.

Abstract: A multiple-module, oil-flooded, rotary screw compressor wherein a plurality of compressor modules are driven by a single drive shaft. The modules are positioned in parallel so that a large volume of compressed air can be provided for use in equipment which continuously requires a large supply of such air. The compressor is configured so that each rotary screw compressor module includes a driven gear engaged with the same gear on the drive shaft. The compressor modules may share a common inlet cavity and a common outlet cavity.

Abstract: The inlet bearings of a screw machine, such as a refrigerant compressor, are both lubricated and cooled by a portion of the motor cooling and suction flow which has lubricant entrained therein and which is drawn through the inlet bearings into the coacting pair(s) of screw rotors.

Abstract: The invention concerns a compressor installation with a water-injected compressor element (1) having a water cycle (6) and a water supply device (15) for supplying water to the water cycle (6), containing a water supply line (16) with a controllable valve (18) and a reverse osmosis filter (17) therein. Onto the water cycle is connected a by-pass (21) in which are erected an ion exchanger (22) and a controllable valve (23). A valve (18) in the water supply line (16) is controlled by a device (20) for measuring the amount of water in the water cycle (6), and the valve (23) in the by-pass (21) is controlled by a device (24) for measuring the conductivity of the water.

Abstract: A feed pipe 26 for a sealing water is connected to a housing of the pump to communicate with an enclosed chamber which is defined between a position in which a helical seal line of screw rotors 17 isolates the enclosed chamber from a suction port 15 of the pump and another position in which the enclosed chamber begins to open to a discharge port 24. Alternatively, a feed pipe for the sealing water is connected to the suction port 15 of the vacuum pump, and the feed pipe 26 is provided with a valve V which opens when the suction pressure of the sealing water becomes lower than −380 mmHg.

Abstract: In order to improve a screw compressor for compressing a working medium, comprising an outer housing, two screw rotors which are arranged in the outer housing in rotor bores provided for them and a drive for the screw rotors, in such a manner that the sealing gap is subject to as little variation as possible it is suggested that a compressor screw housing, in which the rotor bores for the screw rotors are arranged, be provided within the outer housing and that a space be arranged between a substantial part of the compressor screw housing and the outer housing.

Abstract: Scroll compressors having a non-orbiting scroll the type that moves axially for a limited distance are provided with an economizer fluid tube. The economizer tube is received within an opening in the non-orbiting scroll such that the non-orbiting scroll can move relative to the tube. This is an improvement over the prior art, and provides a more secure and simple connection.

Abstract: A refrigerating apparatus comprising a refrigeration cycle comprising at least a compressor, a condenser, a dryer, an expansion mechanism and an evaporator, a refrigerant composed mainly of a fluorocarbon type refrigerant containing no chlorine and having a critical temperature of 40° C. or higher, and a refrigerating machine oil comprising as base oil an ester oil of one or more fatty acids which contains at least two ester linkages in the molecule and has a viscosity at 40° C. of 2 to 70 cSt and a viscosity at 100° C. of 1 to 9 cSt.

Abstract: A rotary-screw air compressor having a separator, a cooler fan assembly, and a mounting apparatus. The separator has a first chamber and a second chamber. The first chamber separates compressed air and coolant. The second chamber separates compressed air and moisture. The separator is disposed in a chasm formed by a first platform. The mounting apparatus elevates a motor and air end vertically above and spatially apart from the separator. A cooler fan assembly is vertically above the motor and air end. The cooler fan assembly has a first heat exchanger vertically above a second heat exchanger. A shroud having an opposite open end is connected to the first heat exchanger at one open end and the shroud is connected to the second heat exchanger at the other open end. A cooler fan is disposed completely within the shroud and between the first and second heat exchangers.

Abstract: Scroll compressors are provided with injection ports for injecting fluid from a supplemental source such as an economizer cycle or by-passing fluid through an unloader valve. The injection ports are formed in each of two compression chambers whose volume is being reduced towards a discharge port. Due to various design constraints, it is desirable that the injection ports have unequal characteristics. In some cases, it may be desirable to make the injection ports of different size, including width, depth, and length. In other applications, it may be desirable to locate the injection ports at different angular positions relative to compression chambers seal off from suction.

Abstract: An oil distribution system for machinery such as a vacuum pump is disclosed. The system features an auxiliary oil pump integrally mounted adjacent to one end of the vacuum pump's drive shaft. The drive shaft drives the oil pump and has a longitudinal passage extending substantially along its length in communication with the outlet from the oil pump. Oil ports, positioned at points along the drive shaft adjacent to bearings supporting the drive shaft, extend from the passage. Lubricating oil, drawn from a reservoir by the oil pump, is pumped into the passage. The oil exits the passage via the oil ports and lubricates the bearings. The oil passes into the pump cylinder where it provides an oil seal between the piston and cylinder wall. Either a rotary vane pump or a gerotor-type pump is preferred as the auxiliary oil pump.

Abstract: A compressor in accordance with the present invention includes a male rotor which is axially aligned with and in communication with two female rotors. The compressor includes a housing and a thrust balance configuration. The thrust balance configuration includes a thrust balance disc mounted to a male rotor shaft in a discharge housing of the compressor. The thrust balance disc is exposed to fluid from the compressor at high pressure. The outside diameter of the thrust balance is sized to provide sufficient area to react thrust loads produced by the first rotor. The thrust balance configuration serves to balance the thrust loads imparted on the male rotor and allows for full axial discharge porting.

Abstract: Upon starting instruction of a compressor before the compressor is started, a pressurized water jet line 20 is opened and pressurized water is jetted to the inside of the compressor. By this manner, a dry operation with rotors and a mechanical seal kept in a dry state is definitely prevented and the compressor can be started even after it is stopped for a long hour. Further, the compressed air is supplied to the inside of the water tank, and the water from the water tank is jetted to the inside of the compressor by its pressure. The compressed air ejected from the water tank is cooled below a saturation temperature of water content and the water content thereof is condensed and separated. The separated water content is supplied to the inside of the compressor, and an excess circulating water is discharged from the water tank. Thus, a long hour continuous operation can be performed without replenishing water.

Abstract: The invention concerns an oil-sealed vane-type rotary vacuum pump (1) with a rotor (3) and an oil pump (45, 46) whose suction chamber is fitted with feeds (64, 65) for gas and oil. In order to simplify the supply of a gas/oil mixture to the vacuum pump, the invention proposes that the gas and oil feeds (64, 65) are disposed in such a way that initially only oil and subsequently both oil and air are aspirated into the volume swept by the oil pump (45, 46) as it rotates.

Abstract: A compressor system for creating essentially liquid-free fluid flows includes a screw compressor that has an inlet port for receiving a low pressure gas stream, a main lubrication injection port for receiving an injection branch of a filtered lubrication stream, an inlet bearing lubrication port for receiving an inlet branch of the filtered lubrication stream, a discharge bearing and seal lubrication port for receiving a discharge branch of the filtered lubrication stream, a prime mover for powering the rotary screw compressor and a discharge port for discharging a high pressure compressed gas mixture stream from the compressor. The system further includes a separator for receiving the compressed gas mixture stream from the compressor. The separator has at least a primary and a secondary coalescer devices connected in series, such that the primary coalescer device has a smaller surface area than the secondary coalescer device.

Abstract: A CO.sub.2 compressor is disclosed for forcing and moving a lubricant under discharge pressure. If the oil path is reduced in size or a pressure reducing part is inserted to handle the large differential pressure caused between the discharge pressure and the intake pressure, the oil path would become liable to be easily clogged by foreign matter. In view of this, an intermittent oil supply mechanism is formed in the oil path using the sliding contact portion between a fixed member of the compressor body and a movable member. Thus, the substantial lubrication time period is shortened and the amount of oil supplied is limited.

Abstract: The invention relates to a compressor installation (10) with an injection-cooled compressor (12) and a method for compressing a gas in a compressor installation. In order to allow for an environmentally acceptable compression of gaseous media, the compressor system (10) is cooled with oil-free cooling water (25) free of additives. The cooling water injection into the compressor (12) is dosed such that the compression is almost isothermal. Further, a water treatment device (31) for preventing mineral deposits is provided that modifies the cooling water (25) such that the formation of mineral deposits in the cooling circuit is prevented.

Abstract: A device is provided for sealing a rotor shaft supported on a bearing mounted in a housing of an appliance for compressing or expanding a fluid containing, apart from the housing, at least one rotor mounted therein. The sealing device is situated between the rotor and the bearing around the rotor shaft and includes at least two zero contact or frictionless seals. The sealing device successively includes between the rotor and the bearing a first zero contact seal; a double, reverse lip seal with two lips; and a second zero contact seal. The two lips are partly directed towards one another and partly directed towards the rotor shaft along their backsides. An entry for fluid under pressure opens between the lips, whereby the lips, depending on the pressure between them, are in contact with to the rotor shaft or are lifted from the rotor shaft.

Abstract: Oil reclamation for a flooded screw type compressor is improved by replacing the normal distillation still with a refrigerant vaporizer made from a small diameter pipe conduit and a low temperature heat source such as heat tracing. The system purifies lubricating oil of refrigerant by boiling small batches of collected lubricating oil from the bottom of the chiller. Using a small volume for vaporization of the refrigerant allows a low temperature heat source to effectively vaporize the refrigerant from the circulating lubricating oil without complicated systems for control or pumping. A particular form of the vaporizer is simply a small diameter pipe surrounded by heat tracing tape.

Abstract: An orbiting scroll is engaged to and moved orbitally in relation to a fixed scroll at variable speeds. An offset surface is provided in at least one of the wraps of the fixed scroll and/or the orbiting scroll, by which a space S is created in one of the compression chambers formed between the fixed scroll and the orbiting scroll, which is thereby unsealed and opened to the inlet port side. The offset surface has a length from a position in the spiral length which satisfies the required compression ratio of one of the compression chambers in a low speed operation to the end of the spiral. An injection port is positioned such as to open to an unsealed area of this compression chamber, and gas injection shutoff and resumption is controlled through this injection port as appropriate to the situation.

Abstract: In a compressor system, a compressor main unit compresses air taken in and exhausts the compressed air with oil. The compressed air and the oil exhausted from the compressor main unit are stored in a reservoir. A head tank has an internal space and is coupled to the compressed main unit and the reservoir. An oil separator which is installed in the head tank separates the oil exhausted from the head tank from the compressed air.

Abstract: Rotary compressor including at least one rotor (2), which is rotatably mounted in a compression chamber (1) by liquid lubricated bearings (4), a device (13-15-16) for injecting water into the compression chamber, and a supply device for supplying (1) a liquid based on polyalkylene glycol miscible with water as the bearing lubricant.

Abstract: A rotary-screw air compressor having a separator, a cooler fan assembly, and a mounting apparatus. The separator has a first chamber and a second chamber. The first chamber separates compressed air and coolant. The second chamber separates compressed air and moisture. The separator is disposed in a chasm formed by a first platform. The mounting apparatus elevates a motor and air end vertically above and spatially apart from the separator. A cooler fan assembly is vertically above the motor and air end. The cooler fan assembly has a first heat exchanger vertically above a second heat exchanger. A shroud having an opposite open end is connected to the first heat exchanger at one open end and the shroud is connected to the second heat exchanger at the other open end. A cooler fan is disposed completely within the shroud and between the first and second heat exchangers.

Abstract: An expansion/separation compressor system is presented for a multi-rotor compressor configuration. In accordance with the present invention the rotors are disposed in a shell having open and closed off portions for providing expansion, compression and separation. The closed off portions depend from or are attached to other suitable compressor structure including the induction or discharge plates. In an embodiment the expansion portion is comprised of a sliding valve. Separation is achieved when the flute and respective open shell portion expose the fluid to basic plenum pressure. The fluid is essentially removed by centrifugal force through the opening in the shell. The compressor is mounted to an evaporator and a control system is provided to regulate the temperature of water in the evaporator thereby controlling the rate of evaporation of liquid phase refrigerant in the evaporator. The liquid phase refrigerant is expanded between the rotors and respective shell portions to a desired volume.

Abstract: The invention shows an improvement in the lubrication of bearings and shaft seals of screw compressors for refrigerants with oils soluble in refrigerants. A typical application results, for example, for ammonia with polyalkylene glycol soluble therein. Due to the fact that a partial oil flow is taken out of the oil flow returned to the screw compressor at an intermediate pressure prior to a pressure reduction to nearly suction pressure of the compressor and conveyed via a vapor separation container, substantial proportions of the dissolved refrigerant can be fed in at an intermediate pressure connection on the compression path of the screw compressor. Correspondingly more advantageous are the lubrication properties of the remaining partial oil flow at the lubrication connection, and the disadvantages of pressure collapse or foam conveyance at an oil pump are absent, since no oil pump is required with a suitable intermediate pressure.

Abstract: A rotary displacement compressor having an inlet channel for introducing low pressure gas, an outlet channel through which compressed gas escapes, and at least one rotor mounted in bearings and operating in a working space. The compressor includes a liquid injector for injecting liquid into the working space, a liquid separator provided in the outlet channel for separating liquid from the compressed gas, and a pressure liquid conduit connecting the liquid separator and the liquid injection port. A bearing lubrication circuit includes a tank, a pump, a supply conduit for supplying liquid from the pump to the bearings in which the rotor is mounted, a withdrawal conduit for withdrawing liquid from the bearings to the tank, and a pump inlet conduit for supplying liquid from the tank to the pump.

Abstract: A scroll compressor having injection ports 70A and 70B opened to operating chambers Vc during a predetermined period of a complete compression cycle, so that a part of the refrigerant circulating in a refrigerating system is injected into the compression chambers from the injection ports. The injection ports are opened to an intermediate pressure chamber, which is at a pressure between the pressure of the refrigerant sucked into the compressor and the pressure of the refrigerant discharged from the compressor. The intermediate pressure chamber is arranged so as to eliminate pressure pulsations therein. Check valves 72A and 72B are provided in an end plate 54 of a stationary scroll member 50. Furthermore, relief valves may also be provided in the end plate for releasing the pressure of the operating chambers to a low pressure side of the refrigerating system.

Abstract: The invention relates to a vacuum pump (1) with an oil separator (42) connected downstream of its outlet (33) and with a duct (45, 46) through which the oil separated in the oil separator (42) is returned to the vacuum pump (1); to feed back the oil in a simple manner, the oil feed duct (45, 46) opens into a duct (47) that supplies gas ballast to the pump (1).

Abstract: A rotary screw compressor having two rotors, liquid injection, a liquid separator (10), and a hydraulic thrust balancing piston (11) connected to at least one of the rotors. In order to vary the balancing force if suction and delivery pressures vary, there is provided first (5) and second (4) throttling devices in the return pipe from the oil separator to the liquid injection port. Between the first and second throttling devices there is a connection to a pipe branch (7) which ends in a cylinder (14) which houses the balancing piston (11). The balancing pressure acting on the balancing piston (11) will thereby vary as suction and delivery pressures vary in a way determined by the relation between the degree of throttling in the two throttling devices.

Abstract: A rotary vacuum pump having a low vacuum stage and a high vacuum stage. Each stage includes a stator body having a bore and a rotor mounted eccentrically in the bore to form a cavity between the stator body and the rotor. The rotor of each stage has two vanes slidably positioned in diametrically opposed slots in the rotor which in use of the pump are substantially in contact with an inner wall of the stator body during rotation of the rotor. The stator body of each stage has an inlet and an outlet to allow, in use of the pump, fluid being pumped to enter into and be expelled from the cavity by means of the rotating vanes. Oil to be injected into the low vacuum stage and, when required, into the high vacuum stage also. Differential flow rates (including zero) of ballast gas are introduced to the low vacuum stage, for example in an amount in excess of ten percent of the overall vacuum pump capacity (which equates to the capacity of the high vacuum stage).

Abstract: In a high side rotary compressor, interior shell pressure is used to force lubricant from the sump into the compression chamber. The lubricant is delivered only after the suction port has closed and before chamber pressure exceeds shell pressure.

Abstract: A hermetically sealed rotary compressor includes a generally cylindrical sealed vessel having an oil reservoir defined therein for accommodating a quantity of lubricating oil, a drive unit within the sealed vessel, and a compressor mechanism within the sealed vessel. The compressor mechanism includes a cylinder having a compression compartment defined therein and also having upper and lower openings, an eccentric cam provided on a crankshaft for rotation together therewith, and a ring-shaped piston mounted on the crankshaft while encircling the eccentric cam and capable of undergoing a planetary motion in contact with the eccentric cam during rotation of the eccentric cam. The cylinder has a refrigerant intake port defined therein in communication with the compression compartment.

Abstract: A non-contact vane-type fluid-displacement machine includes a stator housing having an annular interior surface defining an interior bore and a rotor supported in an eccentric position in the interior bore of the stator housing relative to the annular interior surface thereof to undergo rotation relative to the stator housing about a central rotational axis. The rotor has at least one slot radially defined therein relative to the rotational axis. The machine also has at least one vane disposed in radial slot of the rotor. The vane is mounted to the rotor to undergo reciprocable movement in a radial direction relative to the rotational axis of the rotor such that an outer tip portion of the vane is maintained in a non-contacting substantially sealed relationship with the interior surface of the stator housing. Improved features of the machine relate to a lubricant separator and sump arrangement incorporated in the stator housing of the machine.

Abstract: A scroll-type compressor has a liquid injection system for injecting liquid into an enclosed space defined by first and second scroll members which engage in cyclical relative orbiting motion, to reduce the temperature of the working fluid. The compressor incorporates a discharge diffuser for reducing the pressure of the working fluid in an enclosed space, so that the liquid may be injected into the enclosed space from a more centrally located injection port than one which would allow liquid injection without the discharge diffuser.

Abstract: A scroll-type refrigerant compressor for use in a conventional refrigerating circuit and having liquid refrigerant compressor cooling provided by the injection of liquid refrigerant into an intermediate biasing chamber and/or specifically located bleed holes.

Abstract: A scroll-type refrigerant compressor for use in a conventional refrigerating circuit and having liquid refrigerant compressor cooling provided by the injection of liquid refrigerant into an intermediate biasing chamber and/or specifically located bleed holes.

Abstract: An apparatus for regulating a compressor lubrication system includes an oil-flooded rotary gas compressor, a reservoir flow connected to the compressor, a heat exchanger for cooling a lubricant, and a controller. A thermal mixing valve regulates the temperature of the lubricant flowing to the compressor. A first temperature sensor measures a discharge temperature at a compressor outlet, and provides a signal corresponding to the discharge temperature to the controller. A second temperature sensor measures a lubricant temperature at a lubricant inlet to the compressor, and provides a signal corresponding to the lubricant temperature to the controller. A pressure sensor measures the pressure at the outlet of the compressor, and provides a corresponding pressure signal to the controller. A valve means continuously regulates the supply of lubricant to the compressor, the valve means being controlled by the controller in response to the temperature signal of the first temperature sensor and the pressure signal.

Abstract: A rotary compressor such as a screw-type or a spiral compressor comprises a compressor stator and one or more rotary compression elements, which compressor stator is provided with a suction port, a delivery port and a lubricant inlet, the lubricant being intended for lubricating each compression element, for sealing the gaps between the individual compression elements and between the compression elements and the compressor stator, and for cooling the medium to be compressed during the compression process. The compressor also comprises an inlet for a cooling medium for cooling the lubricant which opens out near or in the delivery port.

Abstract: A hermetic type refrigerant compressor operates using a refrigerant and a refrigerator oil in which the refrigerant is soluble. The refrigerant compressor includes slidable members adapted to slidably move and a compressing mechanism for compressing the refrigerant with the aid of the slidable members in a hermetic casing. The refrigerant, the refrigerator oil and the slidable members are selected and constructed in the following manner. The refrigerant is a 1,1,1,2-tetrafluoroethane or a 1,1-difluoroethane, the refrigerator oil is at least one kind of refrigerator oil selected from a polyalkylene glycol based oil and a polyester based oil, and at least one of the slidable members has a slidable surface which is prepared such that a surface hardened layer having a Vickers hardness of 400 or more and a thickness of 2 microns or more is formed on a substrate of ferrous metallic material, and subsequently, an iron oxide layer composed of Fe.sub.3 O.sub.4 as a main component and having a thickness of 0.

Abstract: The present invention is directed to a scroll type compressor having an injection mechanism in which a part of the refrigerant flowing from the condenser is combined with the refrigerant in the intermediately located fluid pockets of the scroll elements in order to increase the amount of heat radiation from the refrigerant in the condenser without increasing the capacity of the compressor and in order to prevent operation of the compressor at a thermally severe condition. The injection mechanism includes a horseshoe-shaped groove formed between a circular end plate of a fixed scroll and an end portion of a casing adjacent to the circular end plate, a pair of axial conduits formed through the end plate of the fixed scroll and an axial hole formed through the end portion of the casing. The refrigerant is conducted to the intermediately located fluid pockets of the scroll elements via the axial hole, the groove and the axial conduits which are connected in series for fluid communication.

Abstract: An oil flooded screw compressor including suction, rotor, and discharge sections having suction, intermediate pressure, and discharge ports, respectively, and an oil sump. The discharge section includes radially spaced internal and external housings, with the internal housing receiving an oil-gas stream from the rotor section. A filter is disposed to surround the internal housing, with the filter including a cylindrical, foraminate body portion, an end wall, and a filter pad against the end wall. The oil-gas stream from the rotor section exits the inner housing, via an opening which forms part of a first stage of oil removal. The oil-gas stream strikes the filter pad, removing oil as the oil-gas stream is forced to turn 90 degrees to exit the filter through the foraminate body portion, which also removes oil. The filter functions as second and third stages of oil removal.

Abstract: In a scroll type compressor, a movable scroll is engaged with an immovable scroll so that spaces are formed for taking in a fluid including a lubricating oil mist to be compressed. The movable scroll is revolved around a central axis of the immovable scroll so that, as the spaces are displaced toward a center of the immovable scroll, a volume thereof is reduced to compress the fluid therein. The immovable scroll has a passage through which each of the spaces is communicated with a discharge chamber upon reaching the center, whereby the compressed fluid is successively discharged through the passage into the chamber. An oil-separating plate is disposed in the chamber at a given level lower than the passage, and a reed valve is provided at the passage.

Abstract: An oil injection type screw compressor includes an oil passage for circulating lubricating oil extending from an oil separator disposed in a discharge passage of a compressor main body through an oil cooler, oil filter and oil pump on the downstream side of the oil pump to parts requiring lubricating oil such as rotors, bearings, shaft sealing members within the compressor main body, the compressor comprising pressure switches for detecting a pressure of a suction passage as a low pressure side, and a pressure of the oil passage between the oil filter and the oil pump as a high pressure side, whereby starting the oil pump when the differential pressure between both the detected pressures is not more than the specified value.

Abstract: A screw-type compressor/expander including a housing having inlet and outlet ends and two matching profile rotors with male and female lobes helically wrapped to form endless screws is characterized by end plates having spaced ports arranged at each axial end of the rotors and valve gates slidable with respect to other end plates to select either compression mode ports or expansion mode parts. When the expansion mode ports are selected, the rotors and housing enclose spaces initially opening to the inlet end that have a volume that expands as the rotors are turned. When the compression mode ports are selected, the rotors and the housing enclose spaces initially opening at the inlet end and then closing such that the volume of the spaces contracts as the rotors are turned.

Abstract: A pumping apparatus for pumping a gas having application to helium leak detectors has a vane and oil-seal type vacuum pump immersed in a closed tank (9) partially filled with oil (10). The apparatus also includes an oil pump (20) for renewing the oil seal located inside the tank. The oil pump is equipped with a noise-reducing mixing device enabling the oil for constituting the oil seal to be mixed with a noise-reducing gas. The noise-reducing gas is fed from the outside of the tank to the mixing device by means of a pipe (24) passing through the wall of the tank and opening via a Venturi tube to the suction duct of the immersed oil pump.

Abstract: An oil cooled compressor includes a compressor body having a low pressure suction passage and a high pressure discharge passage. An oil tank is mounted to the discharge passage such that oil and drain water separated from a compressed gas in the discharge passage collect in the oil tank with water at a lowermost part of the oil tank. A drain water passage separate from a compressed gas discharge passage and an oil discharge passage, connects the lowermost part of the oil tank with a portion of the compressor body which is substantially at the low pressure. Drain water is thereby evaporated from the oil tank and returned to the compressor body.