Compressor, engine or pump with a piston translating along a circular path

Described herein is a device comprising: a chamber wall comprising outer and inner surfaces, wherein the inner surface encloses a lobed chamber with a plurality of lobes and the inner surface comprises segments of arcuate surfaces, each of the segments of arcuate surfaces being tangent with its immediate neighboring segments, and wherein the chamber wall further comprises channels connecting the outer surface and the inner surface of the chamber wall and/or channels through an end surface of the chamber wall; a lobed piston configured to translate along a circular path relative to the chamber wall, the outer surface of the piston and the inner surface of the chamber wall engaged during translation and forming a fluid-tight seal between some portions of the outer surface of the piston and the inner surface of the chamber wall such that enclosed spaces are formed between the piston and the chamber wall.

BACKGROUND

Mechanical power can be derived from pressure differential of fluid such as steam. The history of the steam engine stretches back as far as the first century AD. James Watt developed a steam engine that provides a rotary motion suitable for driving factory machinery. This enabled factories to be sited away from rivers, and further accelerated the pace of the Industrial Revolution. Around 1800, Richard Trevithick introduced engines using high-pressure steam. These were much more powerful than previous engines and could be made small enough for transport applications.

A reciprocating compressor or piston compressor is a positive-displacement compressor that uses pistons driven by a crankshaft to deliver gases at high pressure. The intake gas enters the suction manifold, then flows into the compression cylinder where it gets compressed by a piston driven in a reciprocating motion via a crankshaft, and is then discharged. Applications include oil refineries, gas pipelines, chemical plants, natural gas processing plants and refrigeration plants.

SUMMARY

Described herein is a device comprising: a chamber wall comprising an outer surface and an inner surface, wherein the inner surface encloses a lobed chamber with a plurality of lobes and the inner surface comprises segments of arcuate surfaces, each of the segments of arcuate surfaces being tangent with its immediate neighboring segments, and wherein the chamber wall further comprises channels connecting the outer surface and the inner surface of the chamber wall and/or channels through an end surface of the chamber wall; a lobed piston comprising: an outer surface wherein the outer surface encloses a main body of the lobed piston and the outer surface comprises segments of arcuate surfaces, each of the segments of arcuate surfaces being tangent with its immediate neighboring segments, and wherein the main body has a plurality of lobes located in the lobes of the lobed chamber, and wherein the piston is configured to translate along a circular path relative to the chamber wall, the outer surface of the piston and the inner surface of the chamber wall engaged during translation and forming a fluid-tight seal between some portions of the outer surface of the piston and the inner surface of the chamber wall such that enclosed spaces are formed between the lobes of the piston and the lobes of the chamber wall; a seal plate attached to an end of the main body, wherein the seal plate forms a fluid-tight seal with the chamber wall, the seal plate comprises through holes between two opposing surfaces, and the through holes are configured to be fluidly connected to the enclosed spaces. According to an embodiment, a fixed transportation plate with transportation holes contacts the seal plate to control the connection between the enclosed spaces and output space. When the pressure of fluid in the enclosed spaces is increased to certain value, the through holes of seal plate are connected to the transportation holes of transportation plate, then the fluid inside enclosed spaces can be released to the output space.

Also described herein is a method of generating mechanical power using the device summarized above.

Additionally described herein is a method of compressing and/or driving a fluid using the device summarized above.

DETAILED DESCRIPTION

A device as described herein comprises a chamber wall having an outer surface and an inner surface, the inner surface enclosing a lobed chamber and comprising segments of arcuate surfaces, each of the segments of arcuate surfaces being tangent with its immediate neighboring segments. Two arcuate surfaces “being tangent” as used herein means that the angles between the two arcuate surfaces are zero at an intersecting line between the two arcuate surfaces. The device also comprises a lobed piston located inside the lobed chamber. The piston can have an outer surface comprising segments of arcuate surfaces, each of the segments of arcuate surfaces being tangent with its immediate neighboring segments. The lobes of the piston are located in the lobes of the chamber. The outer surface of the piston encloses a main body of the piston.

The piston is configured to translate along a circular path relative to the chamber wall. Preferably, the piston translates along a circular path concentric with a rotational symmetric center of the chamber wall. Preferably, the piston does not rotate relative to the chamber wall during translation. The outer surface of the piston and the inner surface of the chamber wall are engaged during translation and form a fluid-tight seal between some portions of the outer surface of the piston and the inner surface of the chamber wall, such that enclosed spaces are formed between lobes of the piston and lobes of the chamber wall. As explained in more details below, the enclosed spaces between a lobe of the piston and the lobe of the chamber in which the lobe of the piston is located change volume during translation. The chamber wall has channels connecting the outer surface and the inner surface of the chamber wall. The channels are fluidly connected to the spaces between a lobe of the piston and the lobe of the chamber in which the lobe of the piston is located. As the spaces expand in volume, fluid can be drawn from the channels into the spaces. The chamber wall having channels connecting the outer surface and the inner surface of the chamber wall reduces fluid flow resistance and increases fluid flow rate.

The piston further comprises a seal plate attached to an end of the main body. The seal plate forms a fluid-tight seal with the chamber wall. The seal plate is preferably circular and extends beyond the lobes of the piston. The seal plate has holes between two opposing surfaces and the through holes can be fluidly connected to the enclosed spaces. Preferably, each of the holes is tangent with one segment of arcuate surface of the outer surface of the piston. The holes in the seal plate preferably are through holes and can have any suitable shape such as circular shape.

The device further comprises a transportation plate that is fixed to and forms a fluid-tight seal with the chamber wall. The transportation plate and the chamber wall enclose the piston in the lobed chamber while allowing the piston to translate therein. The transportation plate urges the piston against a bottom of the chamber and restraints the axial position of the piston. The transportation plate has through holes that overlap and fluidly connect to the holes in the seal plate of the piston, when the piston is selected translational positions of the piston relative to the chamber wall.

The holes in the transportation plate can have any suitable shape. The number of the holes in the transportation plate preferably equals the number of the holes in the seal plate. The number of the holes in the transportation plate preferably equals the number of lobes of the lobed chamber. The holes in the transportation plate preferably are located such that portions of the inner surface of the chamber wall overlap each of the holes in the transportation plate.

According to an embodiment, each of the holes of the transportation plate corresponds to each lobe of the lobed chamber. The location of the holes of the transportation plate are configured such that each hole of the transportation plate overlaps with a hole in the seal plate of the piston and fluidly connect to the lobe of the lobed chamber that the hole of the transportation plate corresponds to, only when an enclosed space forms in the lobe between the chamber wall and the piston and fluid in the sealed place is compressed to a predetermined compression ratio. The term “compression ratio” as used herein means the pressure ratio of compressed fluid to uncompressed fluid. The exact location of the holes in the transportation plate can be changed in order to tune the predetermined compression ratio. When a hole in the seal plate of the piston overlaps with a hole in the transportation plate, compressed fluid in the corresponding enclosed space discharges from the enclosed space through the holes. The hole in the transportation plate disconnects from the enclosed space before a volume of the enclosed space reduces to zero. The transportation plate is configured to prevent fluid leakage.

According to an embodiment, the transportation plate may be fixed or rotatable. The transportation plate and the seal plate cooperatively control the connection between the enclosed spaces and output space. The through holes of the transportation plate and the through holes of the seal plate can be arranged such that when the pressure of fluid in the enclosed spaces increases to a certain value, the through holes of the seal plate and the through holes of the transportation plate may overlap so that the fluid inside the enclosed spaces can discharge therefrom.

Compressed fluid discharged from the lobed chamber through the holes of the seal plate can press the seal plate against the chamber wall so as to enhance the fluid-tight seal between the seal plate and the chamber wall, reduce fluid leakage between the seal plate and the chamber wall, reduce fluid leakage between the lobes of the lobed chamber through any gap between the piston and the bottom of the lobed chamber and reduce any friction between the seal plate and the transportation plate.

According to an embodiment, compressed fluid discharged from the lobed chamber can be used to drive lubricant into any drive shaft of the piston, any gap between the piston and the chamber wall, any gap between the seal plate and the transportation plate wherein the lubricant can reduce friction and form fluid-tight seals.

FIG. 1shows an end view of the inner surface100of the chamber wall1(left panel) and an end view of the outer surface200of the piston2(right panel), according to an embodiment. The inner surface100consists of twelve segments of arcuate surfaces:110A,120A,1108,120B,110C,120C,110D,120D,110E,120E,110F and120F. The black triangles mark intersecting lines between neighboring segments. Each segment is tangent to its neighboring segments. For example,110A is tangent to120A and120F;120C is tangent to110D and110C. The inner surface100has n-fold rotational symmetry with point O as its rotational symmetric center, wherein n can be any integer greater than one, such as six. r denotes the shortest distance between a point on120A,120B,120C,120D,120E and120F and point O. R denotes the longest distance between a point on110A,1108,110C,110D,110E and110F and point O. Distance from each of the centers of110A,1108,110C,110D,110E and110F to point O is A. The outer surface200consists of twelve segments of arcuate surfaces:210A,220A,210B,220B,210C,220C,210D,220D,210E,220E,210F and220F. The black triangles mark intersecting lines between neighboring segments. Each segment is tangent to its neighboring segments. For example,210A is tangent to220A and220F;220C is tangent to210D and210C. The inner surface200has n′-fold rotational symmetry with point O′ as its rotational symmetric center, wherein n′ can be any integer greater than one and preferable equals n. r′ denotes the shortest distance between a point on220A,220B,220C,220D,220E and220F and point O′. R′ denotes the longest distance between a point on210A,210B,210C,210D,210E and210F and point O′. Distance from each of the centers of10A,210B,210C,210D,210E and210F to point O′ is A′. A essentially equals A′. (R-R′) essentially equals (r-r′). R is greater than R′. r is greater than r′. The piston2translates along a circular path150of a diameter of (R-R′) and concentric with point O.

FIGS. 2A-2Fshow locations of the piston2relative to the inner surface100of the chamber wall1, as the piston2translates along the circular path150, according to an embodiment. Enclosed spaces, such as enclosed spaces203and204, form between lobes of the outer surface200of the piston2and lobes of the inner surface100of the chamber wall1, when the piston2is at certain translational locations.

Volume of the enclosed spaces203and204change as the piston2translates along the circular path150relative to the chamber wall1. In this particular example, as the piston2translates along the circular path150counterclockwise, the enclosed space203periodically forms, contracts and disappears (i.e., connected to space between another lobe of the inner surface100and the outer surface200, such as shown inFIGS. 2E and 2F); the enclosed space204periodically forms, expands and disappears (i.e., connected to space between another lobe of the inner surface100and the outer surface200, such as shown inFIGS. 2D and 2E). The enclosed space203can be used as a compression chamber to compress and/or increase pressure of fluid therein. The enclosed space204can be used as an intake chamber to draw fluid to be compressed.

FIGS. 3A-3Fcorrespond toFIGS. 2A-2F, respectively, and additionally show the transportation plate3and holes3A therein, the seal plate2B of the piston2and holes2A therein. A long dotted line shows the outer surface of the chamber wall1. A solid line shows the contour of the transportation plate3. The short dotted line shows the contour of the seal plate2B. In this particular example, the piston2translates along the circular path150counterclockwise relative to the chamber wall1. At the location as shown inFIG. 3A, the hole2A is not fluidly connected to the hole3A; the enclosed space204is fluidly connected to a channel1A of the chamber wall1. At the location as shown inFIG. 3B, the enclosed space203has contracted from its state shown inFIG. 3A. Any fluid therein is thus compressed or has elevated pressure. The hole2A barely fluidly connects to the hole3A and fluid in the enclosed space203begins to be discharged from the enclosed space203. The enclosed space204expands and draws fluid from the channel1A of the chamber wall1. At the location shown inFIG. 3C, the hole2A is fully fluidly connected to the hole3A and most fluid in the enclosed space203has been discharged therefrom. The enclosed space204further expands, draws more fluid from the channel1A, and reaches its maximal volume. At location shown inFIG. 3D, the enclosed space203contracts to almost nil and essentially all fluid in therein has been discharged. The hole2A is no longer fluidly connected to the hole3A. The enclosed space204disappears, i.e., connected to space between another lobe of the inner surface100and the outer surface200. At location shown inFIG. 3E, the enclosed space203disappears, i.e., connected to space between another lobe of the inner surface100and the outer surface200. In this particular example, 6 enclosed spaces form, contracts and disappear and 6 enclosed spaces form, expands and disappear while the piston2translates by a full circle along the circular path150.

FIG. 4is a cross-sectional view of a device according to an embodiment. In this embodiment, the channels1A are located through a side wall of the chamber wall1, connecting the outer surface and inner surface of the chamber wall1. The piston2has the seal plate2B fixed to a main body2C of the piston2. The main body2C of the piston2can be viewed as a boss extending from the seal plate2B into the lobed chamber. The term “main body2C” and “boss2C” are used interchangeable here after. The height of the boss2C and the depth of the lobed chamber are substantially equal so as to form seals between the piston2and the chamber wall1. The piston2also has a blind bearing hole open from the seal plate2B, and an oil channel2D connecting the blind bearing hole to an end surface of the boss2C.

The holes3A of the transportation plate3is fluidly connected to a lower chamber40. The holes3A can have a cross-sectional shape of a nozzle, i.e., the opening of the holes3A open to the lower chamber40is larger in area than the opening of the holes3A facing the seal plate2B. Such cross-sectional shape of the holes3A can be effective to lower the fluid flow speed through the holes3A and decrease fluid flow resistance.

A driving shaft5is operably connected with a rotor6A of an electric motor6. An oil channel through the driving shaft5opens at opening5A at one end of the driving shaft5and at opening5B at another end of the driving shaft5.

An upper portion5C of the driving shaft5is disposed in the blind bearing hole of the piston2and rotatably connected to the piston2through a bearing. An axis of the upper portion5C is displaced from an axis of the driving shaft5. The upper portion5C converts the rotational movement of the driving shaft5to the translation of the piston2along a circular path150.

A counterweight4is connected to the driving shaft5to counter centrifugal force caused by translation of the piston2that is eccentric relative to the driving shaft5and to reduce vibration.

A shell8fixed to transportation plate3and chamber wall1, is part of an enclosure that encloses the chamber wall1, piston2, transportation plate3, and has at least one fluid inlet9and at least one outlet11.

Low temperature fluid flows through the inlet9into an upper chamber30, and the channel1A of chamber wall1, into the lobed chamber. The low temperature fluid can be effective to cool the chamber wall1and the piston2and reduce the temperature of the fluid in the lobed chamber and increase compression efficiency. Fluid discharged from the lobed chamber flows through holes2A of piston2and holes3A of transportation plate3into a lower chamber40, then flows through the electric motor6, which can cool the motor6, and into a bottom chamber50. The fluid finally flows through a gap between the motor6and a shell8B and is exhausted through the outlet11.

The fluid in bottom chamber50produces high force on the surface of the oil in an oil pool8D and causes the oil to flow into the driving shaft oil channel opening5A which is submerged in the oil. The oil reaches another end5B of the driving shaft5. Some of the oil flows through a gap in a bearing in the bearing shaft of the piston2and into a gap between the transportation plate3and the seal plate2B so as to reduce friction therebetween. Some of the oil flows through the oil channel2D of piston2and into a gap between the boss2C and the chamber wall1and the lobed chamber so as to reduce friction between the piston2and the chamber wall1, and cool the chamber wall1and piston2. The oil flows through the holes3A and returns to the oil pool8D.

When the oil flows through the oil channel2D into the lobed chamber, and the fluid in the lobed chamber is compressed, the piston2can be urged to move axially away from the chamber wall1, which can break the seal between the chamber wall1and the piston2and cause leakage. High pressure fluid in the lower chamber40exerts force through holes3A onto the seal plate2B and pushes the piston2against the chamber wall1, which enhances seal of between the chamber1and the piston2.

FIG. 6is a vertical sectional view of a device according to an embodiment. In this embodiment, the channels1A are located through a side wall of the chamber wall1, connecting the outer surface and inner surface of the chamber wall1. The channels1A′ can also be located through an end surface of the chamber wall1shown inFIG. 5.

The piston2has the seal plate2B fixed to a main body2C of the piston2. The main body2C of the piston2can be viewed as a boss extending from the seal plate2B into the lobed chamber. The term “main body2C” and “boss2C” are used interchangeable here after. The height of the boss2C and the depth of the lobed chamber are substantially equal so as to form seals between the piston2and the chamber wall1. The piston2also has a blind bearing hole open from the seal plate2B, and an oil channel2D connecting the blind bearing hole to an end surface of the boss2C.

The holes3A of the transportation plate3is fluidly connected to a lower chamber40A. The holes3A can have a cross-sectional shape of a nozzle, i.e., the opening of the holes3A open to the lower chamber40is larger in area than the opening of the holes3A facing the seal plate2B. Such cross-sectional shape of the holes3A can be effective to lower the fluid flow speed through the holes3A and decrease fluid flow resistance.

A high pressure shell21is fixed with the transportation plate3, is used to collect high pressure fluid discharged from holes3A in transportation plate3.

A driving shaft5is operably connected with a rotor6A of an electric motor6. An oil channel through the driving shaft5opens at opening5A at one end of the driving shaft5and at opening5B at another end of the driving shaft5.

An upper portion5C of the driving shaft5is disposed in the blind bearing hole of the piston2and rotatably connected to the piston2through a bearing. An axis of the upper portion5C is displaced from an axis of the driving shaft5. The upper portion5C converts the rotational movement of the driving shaft5to the translation of the piston2along a circular path150.

A counterweight4is connected to the driving shaft5to counter centrifugal force caused by translation of the piston2that is eccentric relative to the driving shaft5and to reduce vibration.

A shell8which is fixed to transportation plate3and chamber wall1, is part of an shell that encloses the chamber wall1, piston2, transportation plate3, and has at least one fluid inlet9A and at least one outlet11A.

Low temperature fluid flows through the inlet9A into a chamber30A inside the shell21, through the motor6so as to cool the motor6, into a chamber30B, through a space30C between the motor6and the shell21so as to cool the motor6, through a gap30D between the transportation plate3and the shell21into a chamber30E. Fluid in the chamber30E then flows through the channel1A of chamber wall1, into the lobed chamber. The low temperature fluid can be effective to cool the chamber wall1and the piston2and reduce the temperature of the fluid in the lobed chamber and increase compression efficiency. Fluid discharged from the lobed chamber flows through holes2A of piston2and holes3A of transportation plate3into a chamber40A, and finally is exhausted through the outlet11A.

The fluid in the chamber30B produces high force on the surface of the oil in an oil pool8D and causes the oil to flow into the driving shaft oil channel opening5A which is submerged in the oil. The oil reaches another end5B of the driving shaft5. Some of the oil flows through a gap in a bearing in the bearing shaft of the piston2and into a gap between the transportation plate3and the seal plate2B so as to reduce friction therebetween. Some of the oil flows through the oil channel2D of piston2and into a gap between the boss2C and the chamber wall1and the lobed chamber so as to reduce friction between the piston2and the chamber wall1, and cool the chamber wall1and piston2. The oil flows through the holes3A,21A and returns to the oil pool8D.

When the oil flows through the oil channel2D into the lobed chamber, and the fluid in the lobed chamber is compressed, the piston2can be urged to move axially away from the chamber wall1, which can break the seal between the chamber wall1and the piston2and cause leakage. High pressure fluid in the lower chamber40A exerts force through holes3A onto the seal plate2B and pushes the piston2against the chamber wall1, which enhances seal of between the chamber1and the piston2.

FIG. 7is a vertical sectional view of a device according to an embodiment. The device in this embodiment can be used to transport clean fluid. In this embodiment, the channels1A are located through a side wall of the chamber wall1, connecting the outer surface and inner surface of the chamber wall1. The channels1A′ can also be located through an end surface of the chamber wall1shown inFIG. 5. The chamber wall1has at least one groove1C located in and open to a surface of the chamber wall1, wherein the surface faces the seal plate2B. The groove1C is filled in lubricant effective to form a fluid-tight seal and provide lubrication between the seal plate2B and the chamber wall1.

The piston2has the seal plate2B fixed to a main body2C of the piston2. The main body2C of the piston2can be viewed as a boss extending from the seal plate2B into the lobed chamber. The term “main body2C” and “boss2C” are used interchangeable here after. The height of the boss2C and the depth of the lobed chamber are substantially equal so as to form seals between the piston2and the chamber wall1. The piston2also has a blind bearing hole open from the seal plate2B. The boss2C has at least one groove2E located in and open to an end surface of the boss2C, wherein the end surface faces the chamber wall1. The groove2E is filled in lubricant effective to form a fluid-tight seal and provide lubrication between the boss2C and the chamber wall1.

The holes3A of the transportation plate3is fluidly connected to a lower chamber40B. The holes3A can have a cross-sectional shape of a nozzle, i.e., the opening of the holes3A open to the lower chamber40B is larger in area than the opening of the holes3A facing the seal plate2B. Such cross-sectional shape of the holes3A can be effective to lower the fluid flow speed through the holes3A and decrease fluid flow resistance. The transportation plate3has at least one groove3B located in and open to a surface of the transportation plate, wherein the surface faces the seal plate2B. The groove3B is filled in lubricant effective to form a fluid-tight seal and provide lubrication between the seal plate2B and the transportation plate3.

A high pressure shell21is fixed with the transportation plate3, is used to collect high pressure fluid comes from holes3A in transportation plate3. The said high pressure shell21has groove21A in which filled with material of lubrication and seal.

A high pressure shell21is fixed with the transportation plate3, is used to collect high pressure fluid discharged from holes3A in transportation plate3. The shell21has at least one outlet11B.

A low pressure shell22is fixed with the chamber wall1. The shell22has at least one inlet9B.

A driving shaft5can be connected to a motor (not shown inFIG. 7).

An upper portion5C of the driving shaft5is disposed in the blind bearing hole of the piston2and rotatably connected to the piston2through a bearing. An axis of the upper portion5C is displaced from an axis of the driving shaft5. The upper portion5C converts the rotational movement of the driving shaft5to the translation of the piston2along a circular path150.

An anti-rotation ring12can be disposed in the device and operable to prevent rotation of the piston2during the translation of the piston2along the circular path150.

A counterweight4is connected to the driving shaft5to counter centrifugal force caused by translation of the piston2that is eccentric relative to the driving shaft5and to reduce vibration.

Low temperature fluid flows through the inlet9B into a chamber30F inside the shell22, through heat sink fins1B on the chamber wall1so as to cool the chamber wall1. Fluid in the chamber30F then flows through the channel1A of chamber wall1, into the lobed chamber. The low temperature fluid can be effective to cool the chamber wall1and the piston2and reduce the temperature of the fluid in the lobed chamber and increase compression efficiency. Fluid discharged from the lobed chamber flows through holes2A of piston2and holes3A of transportation plate3into a chamber40B, and finally is exhausted through the outlet11B.

When the fluid in the lobed chamber is compressed, the piston2can be urged to move axially away from the chamber wall1, which can break the seal between the chamber wall1and the piston2and cause leakage. High pressure fluid in the lower chamber40B exerts force through holes3A onto the seal plate2B and pushes the piston2against the chamber wall1, which enhances seal of between the chamber1and the piston2.

Each pair of surface the move relative to each other is lubricated by solid lubricant to reduce friction loss and enhance seal therebetween. For example, grooves1C and2E provide lubricant and form a fluid-tight seal between the chamber wall1and the piston2.FIG. 8shows a top view of an exemplary chamber wall1with the groove1C.FIG. 9shows a top view of an exemplary piston2with the groove2E. Groove3B provides lubricant and form a fluid-tight seal between the seal plate2B and the transportation plate3.FIG. 10shows a top view of an exemplary transportation plate3with the groove3B. The transportation plate3can further have a groove3C in and open to a surface facing the driving shaft5to provide lubricant and form a fluid-tight seal between the transportation plate3and the driving shaft5. The shell21can have a groove21A in and open to a surface facing the driving shaft5to provide lubricant and form a fluid-tight seal between the shell21and the driving shaft5. The grooves1C,2E,3B,3C can be arranged in any suitable fashion. The device can have any suitable number of grooves to provide lubricant.

FIG. 11is a vertical sectional view of a device according to an embodiment.FIG. 12is a sectional view of the surface A-A inFIG. 11, with the piston2, the chamber wall1and the transportation plate3overlaid thereon.FIG. 13is a view of the device inFIG. 11from the top of the device with a shell removed. Same reference numerals inFIGS. 11-13refer to the same feature.

In this embodiment, a flow regulation plate101is rotatably attached to and forms a fluid-tight seal with the chamber wall1, and forms the bottom of the lobed chamber. The flow regulation plate101can be attached to the chamber wall1by any suitable means, such as being retained in a recess on the chamber wall1by a cover plate102. The cover plate102is effective to maintain a fluid-tight seal between the flow regulation plate101and the chamber wall1.

The flow regulation plate101has connection slots101A in and open to a surface of the flow regulation plate101, the surface facing the lobed chamber. The connection slots101A correspond to the lobes of the lobed chamber.FIG. 12is a top view of an exemplary flow regulation plate101with the chamber wall1and the piston2overlaid thereon. At some rotational positions of the flow regulation plate101relative to the chamber wall1, the connection slots101A connect the enclosed space203as a compression chamber and the enclosed space204as an intake chamber (e.g.,101A″ inFIG. 12, which is one of the slots101A), effectively reducing the volume of the enclosed space203. When the enclosed space203and the enclosed space204are connected by the connection slots101A, fluid can flow between the enclosed spaces203and204through the connection slots101A. By changing the rotational position of the flow regulation plate102relative to the chamber1, the duty cycle of the connection between the enclosed spaces203and204, and the amount of fluid in the enclosed space203, can adjusted. The rotational movement of the flow regulation plate101can be driven by any suitable mechanism. For example, the flow regulation plate101can have a lever slot101B engaged with a drive pole103A of a flow regulation lever103. The flow regulation plate101can have an oil channel101C for delivery of lubricant between the flow regulation plate101and the piston2. The oil channel101C can be fluidly connected to a four-way solenoid valve108.

The piston2has the seal plate2B fixed to a main body2C of the piston2. The main body2C of the piston2can be viewed as a boss extending from the seal plate2B into the lobed chamber. The term “main body2C” and “boss2C” are used interchangeable here after. The height of the boss2C and the depth of the lobed chamber are substantially equal so as to form seals between the piston2and the chamber wall1and between the piston2and the flow regulation plate101. The piston2also has a blind bearing hole open from the seal plate2B, and an oil channel2D connecting the blind bearing hole to an end surface of the boss2C.

The transportation plate3is rotatably attached to the chamber wall1by any suitable mechanism. For example the transportation plate3can be retained in a recess in a support31and urged against the chamber wall1by the support31. The holes3A can have a cross-sectional shape of a nozzle, i.e., the opening of the holes3A open to the lower chamber40is larger in area than the opening of the holes3A facing the seal plate2B. Such cross-sectional shape of the holes3A can be effective to lower the fluid flow speed through the holes3A and decrease fluid flow resistance. The rotation of the transportation plate3can be drive by any suitable mechanism. For example, the transportation plate3can have a lever slot3B engaged with a drive pole105A of a pre-compression ratio regulation lever105, for driving the transportation plate. Rotation of the transportation plate3and rotation of the flow regulation plate101are linked, which maintains the pre-compression ratio despite change of the volume of the enclosed space203effected by the flow regulation plate101. The term “pre-compression ratio” as used herein means the pressure ratio of compressed fluid in the compression chamber to uncompressed fluid at the moment when the holes2A begins to overlap with the holes3A. The rotation of the flow regulation plate101and the transportation plate103can be linked by any suitable mechanism. In one example, as shown inFIG. 11andFIG. 13, a drive lever106is connected with a slider107A of a hydraulic actuator107and lever axle104, to transfer the from slide107A to lever axle104. The hydraulic actuator107controls the slider107A and drives the lever axle104to rotate. The lever axle104is connected to the flow regulation lever103and the pre-compression ratio regulation lever105.

As shown inFIG. 12, the piston2translates along a circular path150counterclockwise around the symmetry center axis of the chamber wall1. The upper panel ofFIG. 12demonstrates a state without flow regulation, wherein the connection slots101A of the flow regulation plate101are not fluidly connected to any enclosed space203and thus have no influence to compression in the enclosed space203. OA is an initial angular position of one of the connection slots101A; OB is an initial angular position of one of the holes3A. The lower panel ofFIG. 12demonstrates a state with flow regulation. Compared to the state shown in the upper panel ofFIG. 12, the flow regulation plate101rotates around the symmetry center axis of the chamber wall1by an angle AOA′; and the transportation plate3rotates around the symmetry center axis of the chamber wall1by an angle is BOB′. Angle AOA′ is preferably greater than angle BOB'. In the state of the lower panel ofFIG. 12, when the enclosed space203as the compression chamber forms and the enclosed space204as the intake chamber are connected through the connection slot101A″ and thus the fluid inside the enclosed space203is not compressed and flows into the enclosed space204as the piston2translates. When the piston2translates to a position wherein the connection slot101A″ is no longer connected to both the enclosed spaces203and204, the fluid inside the enclosed space204begins to be compressed. Rotation of the transportation plate3and the flow regulation plate101are synchronized such that a nearly constant pre-compression ratio is maintained, which leads to high compression efficiency.

The support31is fixed with the shell8, and has holes31A corresponding to and fluidly connected to the holes3A. Fluid discharged from the holes3A flows through the holes31A into the chamber40. High pressure fluid in the lower chamber40exerts force through holes31A and3A onto the transportation plate3and the seal plate2B, pushes the transportation plate3against the piston2, and pushes the piston2against the chamber wall1, which enhances seal of between the transportation plate3and the piston2, and seal of between the chamber1and the piston2.

The four-way solenoid valve108is used to control the action of the hydraulic actuator107. When the four-way solenoid valve108is not powered, hydraulic fluid is blocked inside the hydraulic actuator107and the slider107A of the hydraulic actuator107is locked. When an increment solenoid of the four-way solenoid valve108is powered, the oil channel101C, which delivers high pressure lubricant (e.g., hydraulic oil) is fluidly connected with an oil chamber107B of the hydraulic actuator107; an oil chamber107C is fluidly connected with an oil channel1D, which delivers low pressure oil. The pressure differential in the oil chambers107B and107A causes the slider107A to move away from the oil chamber107B, which turns the flow regulation plate101and the transportation plate3counterclockwise inFIG. 13. When a decrement solenoid of the four-way solenoid valve108is powered, the oil channel101C, which delivers high pressure lubricant (e.g., hydraulic oil) is fluidly connected with the oil chamber107C of the hydraulic actuator107; the oil chamber107B is fluidly connected with an oil channel1D, which delivers low pressure oil. The pressure differential in the oil chambers107B and107A causes the slider107A to move towards the oil chamber107B, which turns the flow regulation plate101and the transportation plate3clockwise inFIG. 13.

A driving shaft5is operably connected with a rotor6A of an electric motor6. An oil channel through the driving shaft5opens at opening5A at one end of the driving shaft5and at opening5B at another end of the driving shaft5.

An upper portion5C of the driving shaft5is disposed in the blind bearing hole of the piston2and rotatably connected to the piston2through a bearing. An axis of the upper portion5C is displaced from an axis of the driving shaft5. The upper portion5C converts the rotational movement of the driving shaft5to the translation of the piston2along a circular path150.

A counterweight4is connected to the driving shaft5to counter centrifugal force caused by translation of the piston2that is eccentric relative to the driving shaft5and to reduce vibration.

The shell8which is fixed to transportation plate3and chamber wall1, is part of an shell that encloses the chamber wall1, piston2, transportation plate3, and has at least one fluid inlet9and at least one outlet11.

Low temperature fluid flows through the inlet9into a chamber30inside the shell8, through the channel1A of chamber wall1, into the lobed chamber. The low temperature fluid can be effective to cool the chamber wall1and the piston2and reduce the temperature of the fluid in the lobed chamber and increase compression efficiency. Fluid discharged from the lobed chamber flows through holes2A of piston2and holes3A of transportation plate3into a chamber40, through the motor6so as to cool the motor6, into a chamber50, through a space8B between the motor6and the shell8and finally is exhausted through the outlet11.

The fluid in the chamber50produces high force on the surface of the oil in an oil pool8D and causes the oil to flow into the driving shaft oil channel opening5A which is submerged in the oil. The oil reaches another end5B of the driving shaft5. Some of the oil flows through a gap in a bearing in the bearing shaft of the piston2and into a gap between the transportation plate3and the seal plate2B so as to reduce friction therebetween. Some of the oil flows through the oil channel2D of piston2and into a gap between the boss2C and the chamber wall1, a gap between the boss2C and the flow regulation plate101, and the lobed chamber, so as to reduce friction between the piston2and the chamber wall1and the flow regulation plate101, and cool the chamber wall1, piston2and flow regulation plate101. The oil flows through the holes3A and returns to the oil pool8D. The oil is also fed through the oil channel101C to drive the hydraulic actuator107.

When the oil flows through the oil channel2D into the lobed chamber, and the fluid in the lobed chamber is compressed, the piston2can be urged to move axially away from the chamber wall1, which can break the seal between the chamber wall1and the piston2and cause leakage. High pressure fluid in the lower chamber40exerts force through holes3A onto the seal plate2B and pushes the piston2against the chamber wall1, which enhances seal of between the chamber1and the piston2and between the piston2and the flow regulation plate101.

A method of generating mechanical power using the device described herein comprises maintaining a pressure differential between openings of the holes3A of the transportation plate3and openings of the channels1A of the chamber wall1.

A method of compressing and/or driving a fluid using the device described herein, comprises providing the fluid to the channels1A of the chamber wall1and driving the translation of the piston2.

In relation to the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used to preface a feature there is no intention to limit the claim to only one such feature unless specifically stated to the contrary in the claim.

The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made without departing from the scope of the claims set out below.