Abstract: The invention relates to a spindle compressor without operating fluid in the working space with a 2-tooth spindle rotor and a 3-tooth spindle rotor in a surrounding compressor housing-and preferably non-parallel rotation axes of the two spindle rotors, in particular for use in compression refrigeration machines.

Abstract: Pump units are known that have a drive shaft and a rotor, which is driven by the drive shaft and is arranged rotatably in a housing, the drive shaft having an oblique sliding plane, which interacts with the rotor and allows the rotor to nutate with the rotor axis thereof about a drive axis of the drive shaft, the rotor having a set of teeth on the end face of the rotor facing away from the drive shaft, said teeth meshing with a set of teeth formed on a housing of the pump unit, working spaces being formed between the teeth of the rotor and the teeth of the housing, which working spaces can be filled via an inlet and emptied via an outlet. It is disadvantageous that the pump unit has a comparatively large axial installation length, because the drive of the pump unit is arranged on an end of the drive shaft facing away from the rotor. In the pump unit according to the invention, the axial installation length is shortened.

Abstract: Transporter and fish lock including an upper inlet and an upper outlet adapted to be in flow communication with an upper volume of water, and a lower outlet and a lower inlet adapted to be in flow communication with a lower volume of water. The upper inlet and the lower outlet communicate via a downstream passage having a first effective through-flow area, and the lower inlet and the upper outlet communicate via an upstream passage having a second effective through-flow area. The downstream passage includes a first helical rotor having a thread-direction that by a flow directed downstream causes the first rotor to rotate around its axis. The upstream passage includes a second helical rotor, wherein the rotors are mutually connected such that the first rotor drives the second rotor in rotation around its axis, and the second rotor has a thread-direction that upon rotation generates a flow directed upstream.

Abstract: An improved discharge port of a rotary screw compressor is described. A discharge port of a screw compressor generally includes a restrictive portion to help prevent a leakage of working fluid back to a suction side of the compressor. The improved discharge port is configured to have a restrictive portion with a reduced size compared to a restrictive portion of a conventional discharge port, resulting in an enlarged opening of the discharge port compared to a conventional discharge port. The improved discharge port can help discharge the compressed working fluid more quickly than a conventional discharge port, reducing and/or avoiding over-compression of the working fluid. The efficiency gained due to the enlargement of the opening may be more than the efficiency loss due to leakage of working fluid back to the suction side, resulting in a net efficiency gain of the compressor.

Abstract: A compressor for compressing refrigerant in a refrigerant circuit includes a housing defining a compression chamber. A screw rotor is mounted within the housing and configured to form a pocket of high pressure refrigerant and a pocket of low pressure refrigerant within the compression chamber. The screw rotor has a rotor shaft rotating about an axis. A bearing cavity includes at least one bearing rotatably supporting the rotor shaft. A partition through which the rotor shaft extends separates the bearing cavity from the compression chamber. A contacting seal is sealingly engaged with the rotor shaft and disposed in the bearing cavity proximate the partition. A passage has an opening adjacent the rotor shaft between the contacting seal and the compression chamber and in fluid communication with the pocket of low pressure refrigerant.

Abstract: A spindle rotor pair of a spindle compressor has a two-toothed spindle rotor and a three-toothed spindle rotor meshing the other without contact. The wrap angle related to the two-toothed spindle rotor is at least 800 angular degrees. A range of at least 30 m/sec is achieved as the mean circumferential speed of the rotor head. In the transverse section, both spindle rotors have arc sectors and cycloid profile contour flanks. In the case of the two-toothed spindle rotor, they are primarily above its gear-tooth pitch circle and of convex design, however, in the case of the three-toothed spindle rotor, they are below its ear-tooth pitch circle and of concave, i.e., hollow, design. Preferably, the transverse sections of each spindle rotor are symmetrical in a way that in each transverse section, the centre of gravity of the profile surfaces comes to lie on the respective rotor pivot point.

Abstract: The invention relates to a dry-compressing dual-shaft rotary displacement screw spindle pump machine for delivering and compressing gases. The spindle rotor pair therein includes multiple stages, having a primary delivery thread, a secondary delivery thread and a gas outlet collector chamber therebetween. The primary delivery thread head circle diameter decreases in the gas outlet direction, while the foot circle diameter thereof increases correspondingly for an application-specific matching inner “integral” compression ratio. The secondary delivery thread nominal delivery direction is opposite to the primary delivery thread nominal delivery direction. The secondary delivery thread is implemented such that the actual gas flow direction is opposite to the nominal delivery direction thereof, and is always directed away from the gas outlet plenum, having a gas permeation under ambient pressure just as the space in the gearbox.

Abstract: A piston for a pump a hub portion defining opposing outer portions, and inserts configured to provide an adjustable surface coupled to each of the opposing outer portions. The hub portion includes a first hub portion and a second hub portion configured to abut one another. Each of the inserts includes an outer shell and a base portion. The first hub portion includes a plurality of the opposing outer portions, and each of the base portions of the inserts is adjustably coupled to respective opposing outer portions of the first hub portion. A pump includes a housing having an inlet and an outlet, and at least two pistons having a hub portion and inserts. The pump may be a positive-displacement, rotary pump, and the pistons may be circumferential pistons.

Abstract: A screw pump includes a stator having a fluid inlet and a fluid outlet, the stator housing first and second externally threaded, tapered rotors mounted on respective shafts and adapted for counter-rotation within the stator to compress fluid passing from the fluid inlet to the fluid outlet, wherein the threads have a pitch that increases towards the fluid outlet.

Abstract: A single screw compressor structure includes a screw rotor and a casing, which houses the screw rotor. A tapered outer circumferential surface of the screw rotor has a plurality of helical grooves, with an outer diameter that increases from an inlet side toward a discharge side. The casing includes an outer tube member having a circular inner hole to form an interior, and an inner tube member is fixed to the interior of the outer tube member. The inner tube member has a tapered inner surface that opposes the tapered outer circumferential surface of the screw rotor. A single screw compressor further including a gate rotor is assembled by adjusting mesh between the screw rotor and the gate rotor, aligning the tapered outer and inner circumferential surfaces relative to one another, and integrally coupling the outer and inner tube members to each other.

Abstract: The invention pertains to a dry vacuum pump comprising at least one rotating shaft (11) mounted on at least one lubricated bearing (5) and at least one sealing device (9) for sealing off lubricating fluids capable of entering the shaft passage from said bearing (5), said sealing device (9) being installed between the lubricated bearing (5) and a dry pumping stage (7), characterized in that said sealing device (9) comprises a centrifuge element (17) designed to rotate in unison on said shaft (11) and comprising at least one through line (19) capable of separating the lubricating fluids from the fluid that may travel from said bearing (5) to the dry pumping stage (7).

Abstract: In a screw rotor (40), a first suction-side area (45) is formed in a first side wall surface (42) of a spiral groove (41). In the first side wall surface (42), a portion extending from a start point to a point until immediately before a compression chamber (23) is in a completely-closed state defines the first suction-side area (45). The first suction-side area (45) is thinner than a portion of the first side wall surface (42) other than the first suction-side area (45), and does not contact a gate (51) of a gate rotor (50).

Abstract: In a single screw compressor, gates (51) of gate rotors (50) are to be engaged with spiral grooves (41) of a screw rotor (40). In each spiral groove (41) of the screw rotor (40), an area extending from a start point of the spiral groove (41) to a position in a compression stroke is a suction-side portion (45), and the remaining portion (portion up to a terminal point of the spiral groove (41)) is a discharge-side portion (46). In the discharge-side portion (46), a clearance between a wall surface (42, 43, 44) therein and the gate (51) is substantially “0 (zero).” A clearance between the wall surface (42, 43, 44) in the suction-side portion (45) and the gate (51) is wider than that between the wall surface (42, 43, 44) in the discharge-side portion (46) and the gate (51), and is gradually narrowed from the start point toward the terminal point in the spiral groove (41).

Abstract: The claimed invention relates to rotary pumps. The claimed rotary pump comprises: an hollow housing having a side wall and end-face walls; a shaft rotatably positioned in the housing essentially in parallel with the side wall, the distance between the housing side wall and the shaft is variable; deformable rollers that are arranged and adapted to move, when the shaft rotates, between the housing side-wall and the shaft, while moving their deformation being maximal in the region of the minimal distance between the housing side-wall and the shaft; and sealed cavities, each of which cavities being defined by two contiguous rollers, the housing's side wall and end-face walls; the sealed cavities being adapted to communicate with the suction port as their volume increases, and communicate with the delivery port as their volume decreases.

Abstract: A supercharger has an inner wall defining an inner cavity for receiving lobed rotors for rotation therein, a low-pressure inlet and a high-pressure outlet. A sound attenuator is associated with the housing and located adjacent to the high-pressure outlet. The sound attenuator has a tuner chamber and circumferentially spaced tuner ports fluidly connecting the tuner chamber with the internal cavity of the housing to define a Helmholtz resonator. A land is defined between the circumferentially spaced tuner ports such that the high-pressure outlet and low-pressure inner chambers defined between the rotor lobes and the inner wall are fluidly connected when the rotor lobes are in alignment with the land to reduce the pressure differential between the high-pressure outlet and the low-pressure inner chambers.

Abstract: A rotor assembly is provided for a compressor assembly having a housing defining an inlet port, outlet port, and a rotor cavity in communication with the inlet port and outlet port. The rotor assembly includes a rotor body having a plurality of lobes formed thereon and rotatably mountable within the rotor cavity of the housing. The rotor body has a first end, substantially adjacent to the inlet port, and a second end, substantially adjacent to the outlet port, when mounted within the housing. Each of the plurality of lobes has an outer radius that is greater at the first end than at the second end.

Abstract: A fluid pump (10) or motor (100) includes a pair of enmeshed tapered rotors (22,24,122,124) having intersecting axes of rotation. The first rotor (22,122) includes a small low pressure end (34,54,134,154) and a larger high pressure end (32,52,132,152) and a spiral thread (36,56,136,156) that increases in width and depth as it progresses from the high pressure end (28,128) to the low pressure end (26,126). The second rotor (24,124) enmeshes with the first rotor (22,122), and has an identical structure, except that its threads (36,56,136,156) progress in the opposite direction. Both rotors (22,24,122,124) are mounted on sliding splines (42,62,142,162) which permit them to move, to a limited extent, into and out of their respective receiving cavities.

Abstract: A rotor assembly is provided for a compressor assembly having a housing defining an inlet port, outlet port, and a rotor cavity in communication with the inlet port and outlet port. The rotor assembly includes a rotor body having a plurality of lobes formed thereon and rotatably mountable within the rotor cavity of the housing. The rotor body has a first end, substantially adjacent to the inlet port, and a second end, substantially adjacent to the outlet port, when mounted within the housing. Each of the plurality of lobes has an outer radius that is greater at the first end than at the second end.

Abstract: A fluid pump (10) or motor (100) includes a pair of enmeshed tapered rotors (22,24,122,124) having intersecting axes of rotation. The first rotor (22,122) includes a small low pressure end (34,54,134,154) and a larger high pressure end (32,52,132,152) and a spiral thread (36,56,136,156) that increases in width and depth as it progresses from the high pressure end (28,128) to the low pressure end (26,126). The second rotor (24,124) enmeshes with the first rotor (22,122), and has an identical structure, except that its threads (36,56,136,156) progress in the opposite direction. Both rotors (22,24,122,124) are mounted on sliding splines (42,62,142,162) which permit them to move, to a limited extent, into and out of their respective receiving cavities.

Abstract: A positive displacement supercharger includes a housing having a rotor cavity. A pair of positive displacement rotors carry air from an inlet end to an outlet end of the cavity. A gear case adjacent the rotor cavity drives the rotors. The gear case includes an external surface, and an internal end surface facing the rotor cavity. Heat passing from compressed air in the cavity through the internal surface to the gear case oil is at least partially removed by ambient cooling air blown against the external surface of the gear case by a cooling fan. The fan is driven by a rotor drive member and directs the cooling air against the gear case external surface so that the cooling airflow varies with supercharger rotor speed. The fan may have blades extending radially from the drive member axis and may be mounted on a drive pulley or an associated drive shaft.

Abstract: A positive displacement supercharger includes a housing defining a rotor cavity with a pair of positive displacement rotors operative to carry air axially from an inlet end to an outlet in the cavity wall near an outlet end of the cavity. The outlet communicates with an outlet plenum partially defined by the cavity wall. The cavity wall includes a stiff portion defining a plurality of lightening recesses, such as a waffle pattern, limiting distortion of the wall by pulsations in the plenum. The recesses may be time and cost efficiently converted to Helmholtz tuners by covering the recesses with a cover plate, which may be perforated to include at least one tuning opening (perforation) into each tuning chamber (recess) and forming tuning volumes of the tuning chambers and their associated tuning openings effective to attenuate selected frequencies of pulsations in the plenum and thereby reduce undesired noise emanating from the air system of the supercharger.

Abstract: There is designed an equipment with mutually interacting spiral teeth, comprising at least two spiral rotors seating in a stator, where surfaces of the rotor shafts, a rotation wrapper of each of the rotors, each one being furnished with at least one spiral tooth, and a shape of the stator inner further are created by a rotation of a combination of curves having convex and/or concave shape, the curve waveform being defined by shapes of the spiral teeth profiles and their thread lead, provided the spiral teeth profiles and their thread lead, as presented in any section perpendicular to a longitudinal axis of the rotors, are created in relation to required values of pressure, volume and velocity of a media in any part of a working space within the section, the working space being defined as intermediate space between respective spiral rotors themselves and between the rotors and the stator, while the spiral teeth manifest leads of the same or opposite sense.

Abstract: A pump includes a power screw and at least one idler screw which meshes with the power screw, the power screw and idler screw being rotatable in a housing, the idler screw having at least one screw form including a generally helical groove and a generally helical land surface, the land surface having a first, and a second edge portion, each of which is adjacent to the or a groove, the distance between the land surface and a longitudinal axis of the idler screw varying between the first edge portion and the second edge portion, the distance between the first edge portion and the longitudinal axis of the idler screw being substantially constant over the length of the screw form and the distance between the second edge portion and the longitudinal axis of the idler screw being substantially constant over the length of the screw form.

Abstract: A vacuum pump having a screw mechanism and comprising two externally threaded rotors mounted on respective shafts in a pump body and adapted for counter-rotation therein with intermeshing of the rotor threads with close tolerances between the threads and internal surfaces of the pump body in order that gas may be pumped from a pump inlet to a pump outlet by action of the rotor threads, the root diameter of each rotor increases and the thread diameter of each rotor decreases in a direction from the pump inlet to the pump outlet, and wherein the pitch of the rotor threads decreases in a direction from the pump inlet to the pump outlet.

Abstract: A compound vacuum pump includes a pump body divided by a partition into upper and lower chambers. A screw pump section occupies the lower chamber and a Roots-type pump section occupies the upper chamber. The Roots-type pump section comprises two rotors each with a disc for rotation in a bore of the partition.

Abstract: A compound vacuum pump includes a pump body divided by a partition into upper and lower chambers. A screw pump section occupies the lower chamber and a Roots-type pump section occupies the upper chamber. The Roots-type pump section comprises two rotors each with a disc for rotation in a bore of the partition.

Abstract: A vacuum pump includes a pump body in which is mounted two externally threaded rotors. The thread profile of each rotor is tapered in a substantially radial direction to facilitate the machining and fitting of the rotors with the required close tolerances.

Abstract: An asymmetric double screw rotor assembly includes two asymmetric screw rotors respectively revolvably meshed together in a casing having an inlet and an outlet, the spiral threads of the screw rotors defining an uniform pitch, the outer diameter of the first screw rotor and the inner root diameter of the second rotor being uniform, the inner root diameter of the first screw rotor gradually increased from the inlet of the casing toward the outlet, the outer diameter of the second screw rotor gradually reduced from the inlet of the casing toward the outlet. Upon respective rotary motion of the screw rotors, the volume of the respective air chambers gradually reduces from the inlet of the casing toward the outlet.

Abstract: A vacuum pump having a screw mechanism and comprising two externally threaded rotors mounted on respective shafts in a pump body and adapted for counter-rotation therein with intermeshing of the rotor threads with close tolerances between the threads and internal surfaces of the pump body in order that gas may be pumped from a pump inlet to a pump outlet by action of the rotor threads, the root diameter of each rotor increases and the thread diameter of each rotor decreases in a direction from the pump inlet to the pump outlet, and wherein the pitch of the rotor threads decreases in a direction from the pump inlet to the pump outlet.

Abstract: A double screw rotor assembly includes two screw rotors meshed in a bushing inside a casing. The threads of the screw rotors have a constant pitch, and define with the bushing a plurality of air chambers in the pitch. The volumes of the air chambers reduce gradually from the inlet toward the outlet due to reduced tooth height so that the outer diameter defined by the tooth tip of the thread of each screw rotor has the shape of an invertedly disposed cone. An electric driving device is controlled to move the bushing axially in the casing relative to the screw rotors in adjusting the clearance between the inside wall of the bushing and the tooth tip of the thread of each screw rotor, so as to minimize the consumption of starting power and facilitate stable running of the screw rotors, Further, a O-ring is provided at the top wall of the busing and pressed on the casing to keep an airtight status, so as to improve the working efficiency.

Abstract: A double screw rotor assembly includes two screw rotors meshed in a bushing inside a casing. The threads of the screw rotors have a uniform pitch, and define with the bushing a plurality of air chambers in the pitch. The volumes of the air chambers reduce gradually from the inlet toward the output due to the reduce of tooth high so that the outer diameter defined by the tooth tip of the thread of each screw rotor has the shape of an invertedly disposed cone. Adjustable spring means is provided to impart an axial spring force to the bushing relative to the casing, guide means is provided to guide axial movement of the bushing relative to the casing, and a O-ring is disposed between the top wall of the bushing and the casing. Adjusting the pre-loading of the spring means controls the dimension of the clearance between the inside wall of the bushing and the tooth tip of the thread of each screw rotor.

Abstract: A screw pump provided with a first shaft and spaced therefrom and parallel thereto a second shaft mounted in a pump body. A first rotor is mounted on the first shaft and a second rotor mounted on the second shaft. Each of the first and second rotors having formed on an outer surface thereof one or more one helical vanes or threads intermeshing together so that rotary movement of the shafts will cause a fluid to be pumped. A first bearing arrangement is associated with the first shaft and a second bearing arrangement is associated with the second shaft. A bearing carrier is provided for each bearing arrangement and mounted within the pump body so as to be independent from each other.

Abstract: A vacuum pump incorporating a screw mechanism section and comprising two externally threaded rotors mounted on respective shafts in a pump body. The externally threaded rotors are adapted for counter-rotation in a first chamber within the pump body with intermeshing of the rotor threads in order to pump gas from a pump inlet by action of the rotors. The root diameter of each rotor increases and the thread diameter of each rotor decreases in a direction from pump inlet and in which the gas is pumped. The two externally threaded rotors are positioned in the pump body by means of shaft bearings located inside cavities in the rotors. The cavities are sealed at the ends closest to the pump inlet.

Abstract: A power-saving, low-noise double screw rotor assembly, which includes a casing and a pair of screw rotors, wherein the casing has an inside wall defining a compression chamber, an inlet port and an outlet port communicating with the compression chamber. The screw rotors are mounted in the compression chamber and meshed together, each having a spiral thread around the periphery. The thread defines an equidistant pitch. The addendum of the thread defines an outside diameter and is abutted against the inside wall of the casing, the dedendum defines a root diameter. A thread height is defined between the addendum of thread and the dedendum of thread, the thread height gradually reduces in direction from the inlet port toward the outlet port. The dedendum of thread and side walls of the thread of each screw rotor define with the inside wall of the casing at least one transfer chamber having a volume gradually reducing in direction from the inlet port toward the outlet port.

Abstract: A compound vacuum pump incorporating a screw mechanism section. The screw mechanism section comprising two externally threaded rotors mounted on respective shafts in a pump body. The rotors are adapted for counter-rotation in a first chamber within the pump body with intermeshing of the rotor threads to pump gas by action of the rotors. The root diameter of each rotor increases and the thread diameter of each rotor decreases in a direction taken from pump inlet and in which the gas is pumped. The pump additionally incorporates a roots mechanism section comprising two roots-type profile rotors also mounted on the respective shafts and adapted for counter-rotation in a second chamber within the pump body situated at an inlet end of the pump.

Abstract: A scroll-type fluid displacement apparatus comprises a housing having an inlet port and outlet port and a fluid displacement mechanism having a first end and a second end disposed within the housing for displacing a fluid from the inlet port to the outlet port. The fluid displacement mechanism is fixed to the housing by a plurality of fixing members. A discharge chamber is defined by the first end of the displacement mechanism and the housing. A matching surface is defined between the first end of the fluid displacement mechanism and the inner surface of the housing. A sealing device is disposed in the matching surface for sealing the matching surface between adjacent fixing members. Thereby, the scroll-type fluid displacement apparatus has superior axial sealing of the discharge chamber while simultaneously achieving simplifying manufacturing.

Abstract: A screw compressor or pump includes: a housing, two intermeshing rotors respectively rotatably mounted in the housing by two shafts; each rotor having a helix tooth spirally formed on the rotor lengthwise, with the helix tooth gradually decreasing an outer diameter of a top land surface of the helix tooth corresponding to a gradually contracted rotor chamber, and having a spiral groove juxtapositioned to the helix tooth and spirally formed in the rotor lengthwise; the spiral groove having a groove bottom surface extrapolatively defining an inner cone tapered towards a suction port side; the rotor chamber having a conical wall surface extrapolatively defining an outer cone tapered towards a discharge port side, thereby forming a gradationally contracted cavity between the spiral groove and the conical wall surface of the rotor chamber as confined between the inner and outer cones for increasing the compression or pumping efficiency.

Abstract: A nonlubricated screw fluid machine comprising a pair of rotors including a male and a female screw rotors provided with a dual lead tooth profile on the basis of the difference in the temperature between the outlet side and the inlet side when forming a tapered rotors considering the temperature distribution within the rotors in which each of the shape of the male and female rotors after the thermal expansion is employed as a basic tooth profile.

Abstract: A spherical rotary machine which may be embodied as a pump, internal combustion engine, compressor or similar other device includes an outer shell with a substantially spherical interior surface, an inner shell including a substantially spherical outer surface centered within the outer shell, and six rotary pistons located between the inner and outer shell. Each piston is rotatable about its own central axis, the six axes being orthogonally centered on the center of the machine. Each piston includes a top convex spherical surface conforming substantially in shape to and located adjacent to the spherical interior surface of the outer shell, a bottom concave spherical surface conforming substantially in shape to and located adjacent to the spherical outer surface of the inner shell, and an oval conical side surface which is substantially defined by lines which are substantially radial with respect to a point near the machine center.

Abstract: A screw fluid machine in which the distance between a point on each of bore walls and the axis of a male or female rotor decreases at a normal temperature in the vicinity of a high-pressure port as the point proceeds from the low-pressure side to the high-pressure side.

Abstract: A nonlubricated screw fluid machine comprising a pair of rotors including male and female screw rotors provided with a dual lead tooth profile on the basis of the difference in the temperature between the outlet side and the inlet side when forming tapered rotors considering the temperature distribution within the rotors in which each of the shape of the male and female rotors after the thermal expansion is employed as a basic tooth profile.

Abstract: The rotors (M, F) each have a conical outer profile and a constant pitch diameter, the rotors being mounted in opposition in the housing (1) with their axes (2, 3) parallel and their pitch diameters tangent (4). The grooves (5) of the female rotor (F) have a radial depth, in relation to the pitch diameter, which varies in inverse proportion to the outside diameter of the female rotor (F), and which, more specifically, have a circular cross-section the radius of which increases progressively in the direction of reduction of the outside diameter of the female rotor, the center of these radii remaining on the pitch diameter. The rotors are produced advantageously by molding a plastic or by casting a light alloy.

Abstract: A rotary fluid machine of the kind that is to be actuated by any fluid under pressure in which a rotor (15) carrying a piston member (15.sub.4) rotates continuously when the machine is in operation about the axis (AA1) of an annular chamber (21), the piston member (15.sub.4) is geared to rotary obturators (17.sub.A 17.sub.B) that rotate in sealing chambers 21.sub.1 in an annular member 21.sub.2 projecting into the annular chamber 21 about an axis (BB1, CC1) substantially parallel to said axis (AA1) of the annular chamber (21) and the rotary obturator has a recess into which a part of the piston enters during rotation to provide a working section in the cylinder as working fluid is fed to the piston. The machine is characterized in that the piston member (15.sub.

Abstract: A counter-rotating machine, such as a positive displacement pump having a pair of meshed, non-contacting helical screws (10,12), subjects its rotating members to axial and radial thrust forces when used for such purposes as compression of liquid or gaseous phase fluids while transporting them through a pump cavity (11,13). Each helical screw (10,12) has a shaft (17,17') which is actively suspended at opposite ends (11a,11b) of the pump cavity by a servo-controlled magnetic bearing assembly (19) and a servo-controlled rotary drive motor (20). Both bearing assemblies and drive motors are mounted on the outside of the pump cavity (11,13). Opto-electric angular position sensors (250) provide synchronization between radial orientation of the drive motors. The bearing assemblies and drive motors conjugately provide axial stabilization and radial centering of the helical screws during volumetric compression of aspirated liquid or gaseous phase fluids.