WO2022099327A1

WO2022099327A1 - A compressor

Info

Publication number: WO2022099327A1
Application number: PCT/ZA2021/050064
Authority: WO
Inventors: Lorinda CLOETE; Neil Trevor DANOHER; Hendrick Frederick HARDING; James Gilbert MACINTYRE
Original assignee: Cloete Lorinda; Danoher Neil Trevor; Harding Hendrick Frederick; Macintyre James Gilbert
Priority date: 2020-11-05
Filing date: 2021-11-04
Publication date: 2022-05-12

Abstract

The compressor (10) includes a body (12) defining a receiving zone (14) therein, and a compression arrangement (16) arranged within the receiving zone (14) to define a compression chamber (18), the compression arrangement (16) including a plurality of compression members (20) which are displaceable relative each other and the receiving zone (14) for compressing gas within the compression chamber (18) in a stepwise manner.

Description

A COMPRESSOR

TECHNICAL FIELD

This invention relates to a compressor.

SUMMARY OF THE INVENTION

According to the invention, there is provided a compressor including: - a body defining a receiving zone therein; and a compression arrangement arranged within the receiving zone to define a compression chamber, the compression arrangement including a plurality of compression members which are displaceable relative each other and the receiving zone for compressing gas within the chamber in a stepwise manner.

The body may include a head portion and walls extending therefrom to define the receiving zone. The head portion and walls of the body may define the compression chamber together with the compression arrangement. The receiving zone may be sized, shaped and/or configured to receive the compression arrangement complementally therein. Preferably, the receiving zone may have a generally cylindrical shape for receiving a generally cylindrical shaped compression arrangement complementally and/or co-axially therein. It is to be appreciated that the receiving zone and the compression arrangement may have any suitable geometric shape when viewed in plan, for example, circular, ovular, elliptical, elongate or the like. The body may be manufactured from any suitable synthetics, plastics or metallic material, preferably being manufactured from a metallic material and further preferably being manufactured from a combination of steel and aluminium.

The compression members of the compression arrangement may be sized, shaped and/or configured to be rotatably or reciprocally displaceable relative each other. The compression members of the compression arrangement may be sized, shaped and/or configured to be rotatably or reciprocally displaceable relative each other and the receiving zone. Preferably, the compression members may be reciprocally displaceable relative each other and the receiving zone. In particular, the compression arrangement may have a generally cylindrical shape. The compression arrangement may include a first compression member having generally cylindrical shape, preferably resembling a conventional piston. The compression arrangement may include a second compression member having a generally tubular shape defining a cylindrical receiving zone for receiving the first compression member complementally therein. The compression arrangement may include further generally tubular compression members so as to define a substantially nested compression arrangement. Each subsequent compression member may define a progressively larger cylindrical receiving zone for receiving a preceding compression member complementally therein. It is to be appreciated that the compression members may be associated with a portion of the compression chamber within which the compression member is displaced, each compression member preferably being displaced within a discrete volume within the chamber. Preferably, the compression members may be received coaxially within each other, typically being arranged concentrically relative each other. It is to be appreciated that the cylindrical receiving zones may be eccentrically positioned relative the compression member in which the receiving zone is defined. The discrete volumes of each compression member may be defined between compression faces of the respective compression members and the body, preferably an inner surface of the head portion of the body. An area of an annular compression face of an operatively outer compression member may be larger than the surface area of an operatively inner compression member. More particularly, areas of compression faces of operatively outer compression members may have an area larger than those of a compression face of an operatively inner compression member. Furthermore, respective areas of compression faces of a plurality of nested compression members may decrease from an outermost compression member towards an innermost compression member.

In a preferred embodiment of the invention, the compression arrangement may include three compression members, an inner, piston-like compression member, an intermediate tubular compression member arranged around the inner compression member and an outer tubular compression member arranged around the intermediate compression member. An area of an annular compression face of the outer compression member may be larger than the surface area of an annular compression face of the intermediate compression member and/or the surface area of a circular compression face of the inner compression member. The ratio of the outer and intermediate areas may be in the range of 3:1 to 5:1 . The ratio of the outer and inner areas may be in the range of 6:1 and 10:1. The ratio of the intermediate and inner areas may be in the range of 2:1 to 5:1. It is to be appreciated that the respective compression members may be sized according to a desired area ratio which is dependent on the required pressure output.

A first displacement controller may be provided for controlling the displacement of the compression members relative the receiving zone and each other during a compression cycle. The first displacement controller may be configured to ensure that the compression members are displaced through their respective compression strokes one at a time. The first displacement controller may be configured to initiate the compression cycle via an outermost compression member, preferably being followed by intermediate compression members and terminating the compression cycle via an innermost compression member. The first displacement controller may be in the form of a crank arrangement, typically including a crankshaft and a plurality of connectors extending between and interconnecting the compression members and crankpins of the crankshaft. The crankshaft may be shaped and/or configured to cause displacement of the compression members relative each other in an out of phase manner, preferably causing each compression member to perform its compression stroke one at a time. It is to be appreciated that since the crankshaft causes the compression members to perform their compression strokes one at a time, the crankshaft only experiences a load from one compression member at a time which results in a lower power requirement to complete all compression strokes by all compression members. Timing of the displacement of the compression members relative each other may be dependent on the relative position of the crankpins of the crankshaft, the timing typically being dependent on relative angular orientation of the crankpins and/or the crank radius. The connectors of the crank arrangement may be in the form of conventional connecting rods. In particular, the connector extending between and interconnecting the innermost compression member may be in the form of a conventional connecting rod. The connectors may include a pair of connecting members for connecting tubular compression members to the crankshaft. The pair of connecting members may extend between and interconnect opposing side regions of the tubular compression members. Typically, each tubular compression member may be connected to the crankshaft by a pair of connecting rods which extend between corresponding crankpins of the crankshaft and opposing side regions of the tubular compression members.

A displacement means may be provided for displacing the first displacement controller and for causing displacement of the compression members through the compression cycle thereby compressing gas within the compression chamber. The displacement means may be in the form of a motor, which motor may be powered by electricity or internal combustion.

Communication means may be provided for allowing fluid communication between discrete volumes within which each compression member is displaced, the discrete volumes preferably being defined between compression faces of the respective compression members and the body. The communication means may be in the form of a pipe arrangement which may extend between the discrete volumes through side walls of the body. Preferably, the communication means may be in the form of gaps formed between an inner surface of the body and the compression members, typically edge regions thereof. Typically, the gaps may be formed as the compression members are displaced relative each other through their respective compression cycles. For example, in a tri-compression member arrangement, as an outermost compression member completes its compression stroke, gas is allowed to pass from an outer discrete volume through a gap defined by the inner surface of the body and an intermediate compression member and into an intermediate and/or inner discrete volume, and in turn, as the intermediate compression member completes its compression stroke, gas is allowed to pass from the intermediate discrete volume through a gap defined by the inner surface of the body and the innermost compression member and into an innermost discrete volume.

A sealing arrangement may be provided for sealing and/or separating the discrete volumes within which each of the compression members are displaced at predetermined intervals during the compression cycle. In particular, the sealing arrangement may be configured to seal the discrete volumes such that flow of pressurised gas is permitted to flow from one discrete volume to another whilst inhibiting return flow. The sealing arrangement may include a plurality of sealing members which may be displaceably mounted on the head portion of the body. The quantity of sealing members may be dependent on the quantity of compression members, the quantity of sealing members typically being one fewer than the quantity of compression members. The sealing members may be displaceable between an inoperable retracted condition wherein the sealing members are retracted away from the compression members thereby permitting flow of gas between discrete volumes and an extended sealing condition wherein the sealing members extend into the compression chamber thereby closing the gaps between the discrete volumes. The sealing members may be configured to be displaced into the extended sealing condition at predetermined intervals so as to permit the flow of pressurised gas from an outer discrete volume to an inner discrete volume and inhibit return flow. The sealing members may be in the form of generally tubular members which are dimensioned to slide into the compression chamber between the compression members thereby sealing off their respective discrete volumes from each other. Preferably, the sealing members are dimensioned to slide into cut-out portions defined in the compression members. The cut-out portions may be located on outer circumferential regions of the inner compression members. Typically, the plurality of sealing members may be arranged so that they are capable of sliding into the cut-out portions of the compression members during the extended condition thereby forming the seal between discrete volumes. Preferably, the sealing members are arranged to be in register with cut-out portions, the sealing members being arranged in a generally concentric orientation relative each other and the compression members. The sealing arrangement may further include a plurality of O-ring seals arranged between the compression members for inhibiting passage of pressurised gas out of the compression chamber and/or between the discrete volumes of the compression chamber when the sealing members are displaced towards the extended sealing condition. The O-ring seals may be manufactured from a material having improved compression and wear properties, preferably being manufactured from PTFE (polytetrafluoroethylene), which PTFE may be impregnated with glass.

A second displacement controller may be provided for controlling the displacement of the sealing members between the inoperative retracted and extended sealing conditions during a compression cycle. The second displacement controller may be configured to cause a sealing member to be displaced into the extended sealing condition between an outermost and inner compression member when the outermost compression member completes its compression stroke, thereby inhibiting return flow of pressurised gas to the outermost discrete volume as the inner compression member is displaced through its compression stroke. The second displacement controller may be in the form of a cam and cam follower arrangement. Preferably, the second displacement controller may be in the form of a crank arrangement, typically including a crank shaft and a plurality of connecting members extending between and interconnecting the sealing members and crankpins of the crankshaft. In particular, the connecting members may extend between and interconnect corresponding crankpins of the crankshaft and opposing side regions of the tubular sealing members, wherein the opposing side regions of the tubular sealing members extend away from a central axis thereof to allow sufficient space for the connecting members to connect to and displace with the crankshaft in use. It is to be appreciated that inhibiting return flow of pressurised gas prevents the outer compression member from working any further on the same volume of gas during a compression cycle. Timing of the displacement of the sealing members relative the compression members may be dependent on the relative position of the crankpins of the crankshaft, the timing typically being dependent on relative angular orientation of the crankpins and/or the crank radius. A connecting means may be provided for connecting the first and second displacement controllers for ensuring correct and/or constant timing and/or displacement of the respective controllers relative to each other. The connecting means may be in the form of a belt or chain connecting arrangement, preferably being in the form of a chain connecting arrangement. The chain connecting arrangement may include sprockets which are mounted on the crankshafts of the first and second displacement controllers respectively, and a chain extending between and interconnecting the sprockets. The sprockets may be sized so as to cause the crankshaft of the second displacement controller to rotate about twice as fast as the crankshaft of the first displacement controller.

An inlet may be defined in the body for allowing gas to enter the compression chamber. The inlet may be located relative the body such that gas may enter the compression chamber from a region in the vicinity of the compression member completing the first compression stroke of the compression cycle, preferably being the outermost compression member. Preferably, the inlet may be located towards an end region of the body, preferably being defined in the head portion of the body. Further preferably, the inlet may be located towards a periphery of the head portion, typically being defined in the head portion towards a region nearest the walls of the body. It is to be appreciated that the inlet allows gas to enter the chamber into the outermost discrete volume once the outermost compression member completes its compression stroke. A plurality of inlets, preferably a pair, may be defined in the body which may be circumferentially spaced apart from each other for allowing gas to enter the compression chamber via the outermost discrete volume. The pair of inlets may be arranged opposite each other.

An inlet valve may be mounted within the inlet for inhibiting pressurised gas from exiting the compression chamber via the inlet. The inlet valve may be in the form of a one-way valve, non-return valve or a check valve. The inlet valve may be configured to be displaced to an open condition for allowing gas to enter the outermost discrete volume via the inlet when the outermost compression member completes its compression stroke and begins its suction stroke. The inlet valve may be biased towards a closed condition by a spring mechanism.

An outlet may be defined in the body for allowing pressurised gas to exit the compression chamber. The outlet may be located in the region of the compression member completing the final compression stroke of the compression cycle, preferably being the innermost compression member. In particular, the outlet may be defined in the head portion of the body and may be located generally centrally relative the compression chamber for permitting pressurised gas to exit the compression chamber from the innermost discrete volume after the innermost compression member has completed its compression cycle.

An outlet valve may be mounted within the outlet for inhibiting return flow of pressurised gas into the compression chamber. The outlet valve may be in the form of a one-way valve, non-return valve or check valve. The outlet valve may be configured to be displaced to an open condition for allowing pressurised gas to exit the compression chamber via the outlet when the innermost compression members completes its compression cycle. The outlet valve may be biased towards the closed position by a spring mechanism and/or by back pressure which has built up in a reservoir to which the outlet is connected.

A cooling system may be provided for cooling the body and/or compression arrangement during compression of gas within the compression chamber. The cooling system may include a heat sink which may be arranged on an outer surface of the body. In particular, the heat sink may be in the form of plurality of fins which may extend substantially normally away from a side surface of the body, which side surface may substantially surround the compression chamber. The cooling system may further include a fluid cooling means for cooling down the body and/or compression arrangement from within various parts thereof. The fluid cooling means may include a coolant, a plurality of cavities defined in the body and/or compression arrangement, and a pump for displacing the coolant through the plurality of cavities thereby cooling down the body and/or compression arrangement. The coolant may be in the form of an oil coolant. A first cavity may extend through the crankshaft of the first displacement controller through the crankpins, connecting rods and into the compression members for allowing coolant to be pumped into and through the compression members. A second cavity may be located within the walls of the body for allowing coolant to be pumped therethrough. The second cavity may extend throughout the walls of the body for improving heat exchange with the coolant.

Typically, a sump may be provided for receiving coolant therein in use wherein an inlet pipe extends between an operative lower region of the sump and the pump for allowing the pump to receive coolant to be pumped through the cavities defined in the body and/or compression member. Further, piping arrangements may extend between and interconnect the pump and coolant inlets defined in the walls of the body and/or displacement controllers.

BRIEF DESCRIPTION OF THE DRAWINGS

A compressor in accordance with the invention will now be described by way of the following, non-limiting examples with reference to the accompanying drawings.

In the drawings: -

Figure 1 is a three-dimensional cross-section view of the compressor in accordance with the present invention;

Figure 2 is a sectioned plan view of the compressor with the outermost compression member at a bottom dead centre position;

Figure 3 is a sectioned plan view of the compressor with the outermost compression member 30 degrees away from the bottom dead centre position;

Figure 4 is a sectioned plan view of the compressor with the outermost compression member 60 degrees away from the bottom dead centre position; Figure 5 is a sectioned plan view of the compressor with the outermost compression member 90 degrees away from the bottom dead centre position;

Figure 6 is a sectioned plan view of the compressor with the outermost compression member 120 degrees away from the bottom dead centre position;

Figure 7 is a sectioned plan view of the compressor with the outermost compression member 150 degrees away from the bottom dead centre position;

Figure 8 is a sectioned plan view of the compressor with the outermost compression member at a top dead centre position;

Figure 9 is a sectioned plan view of the compressor with the outermost compression member 30 degrees away from the top dead centre position;

Figure 10 is a sectioned plan view of the compressor with the outermost compression member 60 degrees away from the top dead centre position;

Figure 11 is a sectioned plan view of the compressor with the outermost compression member 90 degrees away from the top dead centre position;

Figure 12 is a sectioned plan view of the compressor with the outermost compression member 120 degrees away from the top dead centre position;

Figure 13 is a sectioned plan view of the compressor with the outermost compression member 150 degrees away from the top dead centre position;

Figure 14 is a three-dimensional view of the compressor showing the inside thereof; and

Figure 15 is a sectioned plan view of the compressor which is 90 degrees off from the viewing angle shown in Figures 2 to 13.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, reference numeral 10 refers generally to a compressor in accordance with the present invention. The compressor 10 includes a body 12 defining a receiving zone 14 therein, and a compression arrangement 16 arranged within the receiving zone 14 to define a compression chamber 18, the compression arrangement 16 including a plurality of compression members 20 which are displaceable relative each other and the receiving zone 14 for compressing gas within the compression chamber 18 in a stepwise manner.

The body 12 includes a head portion 22 and walls 24 extending therefrom to define the receiving zone 14. The head portion 22 and walls 24 of the body 12 define the compression chamber 18 together with the compression arrangement 16. The receiving zone 14 is sized, shaped and configured to receive the compression arrangement 16 complementally therein. Typically, the receiving zone 14 has a generally cylindrical shape for receiving a generally cylindrical shaped compression arrangement 16 complementally and co-axially therein. It is to be appreciated that the receiving zone and the compression arrangement may have any suitable geometric shape when viewed in plan, for example, circular, ovular, elliptical, elongate or the like. The body 12 is manufactured from any suitable synthetics, plastics or metallic material, typically being manufactured from a metallic material and further typically being manufactured from a combination of steel and aluminium.

The compression members 20 of the compression arrangement 16 are sized, shaped and configured to be rotatably or reciprocally displaceable relative each other and the receiving zone 14, typically being reciprocally displaceable relative each other and the receiving zone 14 as shown in the Figures. In particular, the compression arrangement 16 has a generally cylindrical shape. The compression arrangement 16 includes a first compression member 20.1 having generally cylindrical shape, typically resembling a conventional piston. The compression arrangement 16 includes a second compression member 20.2 having a generally tubular shape defining a cylindrical receiving zone 26.1 , for receiving the first compression member 20.1 complementally therein. The compression arrangement 16 includes further generally tubular compression members 20 so as to define a substantially nested compression arrangement 16. Each subsequent compression member 20 defines a progressively larger cylindrical receiving zone 26 for receiving a preceding compression member 20 complementally therein. It is to be appreciated that the compression members 20 are associated with a portion of the compression chamber 18 within which the compression member is displaced, each compression member typically being displaced within a discrete volume 28 within the chamber 18. Typically, the compression members 20 are received coaxially within each other, typically being arranged concentrically relative each other. It is to be appreciated that the cylindrical receiving zone 26 can be eccentrically positioned relative the compression member 20 in which the receiving zone 26 is defined. The discrete volumes 28 of each compression member 20 are defined by compression faces 30 of the respective compression members 20 and the body 12, typically an inner surface of the head portion 22 of the body 12. In a preferred embodiment of the invention shown in the Figures, the compression arrangement 16 includes three compression members 20, an inner, piston-like compression member 20.1 , an intermediate tubular compression member 20.2 arranged around the inner compression member 20.1 and an outer tubular compression member 20.3 arranged around the intermediate compression member, the three compression members 20.1 , 20.2 and 20.3 defining inner, intermediate and outer discrete volumes 28.1 , 28.2 and 28.3 respectively. An area of an annular compression face 30.3 of the outer compression member 20.3 is larger than the surface area of an annular compression face 30.2 of the intermediate compression member 20.2 and also larger than the surface area of a circular compression face 30.1 of the inner compression member 20.1. The ratio of the outer and intermediate areas is in the range of 3:1 to 5:1. The ratio of the outer and inner areas is in the range of 6:1 and 10:1 . The ratio of the intermediate and inner areas is in the range of 2:1 to 5:1 . It is to be appreciated that the respective compression members may be sized according to a desired area ratio which is dependent on the required pressure output.

A first displacement controller in the form of a crank arrangement 32 is provided for controlling the displacement of the compression members 20 relative the receiving zone 14 and each other during a compression cycle. The crank arrangement 32 is configured to ensure that the compression members 20 are displaced through their respective compression strokes one at a time. The crank arrangement 32 is configured to initiate the compression cycle via an outermost compression member 20.3, typically being followed by inner compression members, the intermediate compression member 20.2 as shown in the Figures, and terminating the compression cycle via an innermost compression member 20.1. The crank arrangement 32 typically includes a crankshaft 34 and a plurality of connectors 36 extending between and interconnecting the compression members 20 and crankpins 38 of the crankshaft 34. The crankshaft 34 is shaped and configured to cause displacement of the compression members 20 relative each other in an out of phase manner, typically causing each compression member 20 to perform its compression stroke one at a time. It is to be appreciated that since the crankshaft 34 causes the compression members 20 to perform their compression strokes one at a time, the crankshaft 34 only experiences a load from one compression member 20 at a time which results in a lower power requirement to complete all compression strokes by all compression members 20. Timing of the displacement of the compression members 20 relative each other is dependent on the relative position of the crankpins 38 of the crankshaft, the timing typically being dependent on relative angular orientation of the crankpins 38 and the crank radius.

As shown most clearly in Figure 15, the connectors 36 of the crank arrangement 32 are in the form of conventional connecting rods. In particular, the connector 36.1 extending between and interconnecting the innermost compression member 20.1 is in the form of a conventional connecting rod 40. The connectors 36 connecting the outer compression members 20.2 and 20.3 include a pair of connecting rods 42.1 and 42.2 for connecting tubular compression members 20.2 and 20.3 to the crankshaft 34, respectively. The pair of connecting rods 42.1 and 42.2 extend between and interconnect opposing side regions 44 of the tubular compression members 20.2 and 20.3. Typically, each tubular compression member 20.2 and 20.3 is connected to the crankshaft 34 by a pair of connecting rods 42 which extend between corresponding crankpins 38 of the crankshaft 34 and opposing side regions 44 of the tubular compression members 20.2 and 20.3.

A displacement means (not shown) is provided for displacing the crankshaft 34 and for causing displacement of the compression members 20 through the compression cycle thereby compressing gas within the compression chamber 18. The displacement means is in the form of a motor (not shown), which motor is powered by electricity or internal combustion.

Communication means is provided for allowing fluid communication between discrete volumes 28 within which each compression member is displaced. The communication means can be in the form of a pipe arrangement (not shown) which extends between the discrete volumes 28, typically through side walls 24 of the body 12. Typically, as shown in the Figures, the communication means is in the form of gaps 46 formed between an inner surface of the body 12 and the compression members 20, typically edge regions thereof. Typically, the gaps 46 are formed as the compression members 20 are displaced relative each other through their respective compression cycles. For example, in a tri-compression-member arrangement as shown in the Figures, as an outermost compression member 20.3 completes its compression stroke, gas is allowed to pass from an outer discrete volume 28.3 through a gap 46 defined by the inner surface of the body 12 and an intermediate compression member 20.2 and into an intermediate discrete volume 28.2, and in turn, as the intermediate compression member 20.2 completes its compression stroke, gas is allowed to pass from the intermediate discrete volume 28.2 through a gap 46 defined by the inner surface of the body 12 and the innermost compression member 20.1 and into an innermost discrete volume 28.1.

A sealing arrangement 48 is provided for sealing and separating the discrete volumes 28 within which each of the compression members 20 are displaced at predetermined intervals during the compression cycle. In particular, the sealing arrangement 48 is configured to seal the discrete volumes 28 such that flow of pressurised gas is permitted to flow from one discrete volume to another whilst inhibiting return flow. The sealing arrangement 48 includes a plurality of generally tubular sealing members 50 which are displaceably mounted on the head portion 22 of the body 12. The quantity of tubular sealing members 50 is dependent on the quantity of compression members 20, the quantity of tubular sealing members 50 typically being one fewer than the quantity of compression members 20. The tubular sealing members 50 are displaceable between an inoperable retracted condition wherein the tubular sealing members 50 are retracted away from the compression members 20 thereby permitting flow of gas between discrete volumes 28 and an extended sealing condition wherein the tubular sealing members 50 extend into the compression chamber 18 thereby closing the gaps 46 between the discrete volumes 28. The tubular sealing members 50 are configured to be displaced into the extended sealing condition at predetermined intervals so as to permit the flow of pressurised gas from an outer discrete volume to an inner volume and inhibit return flow. The tubular sealing members 50 are dimensioned to slide into the compression chamber 18 between the compression members 20 thereby sealing off their respective discrete volumes 28 from each other. Typically, the tubular sealing members 50 are dimensioned to slide into cut-out portions 51 defined in the compression members 20. The cut-out portions 51 are located on outer circumferential regions of the inner compression members 20. Typically, the plurality of tubular sealing members 50 are arranged so that they are capable of sliding into the cut-out portions 51 of the compression members 20 during the extended condition thereby forming the seal between discrete volumes 28. Typically, the tubular sealing members 50 are arranged to be in register with cut-out portions 51 , the tubular sealing members 50 being arranged in a generally concentric orientation relative each other and the compression members 20.

The sealing arrangement 48 further includes a plurality of O-ring seals 52 arranged between the compression members 20 for inhibiting passage of pressurised gas out of the compression chamber 18 and between the discrete volumes 28 of the compression chamber 18 when the sealing members 50 are displaced towards the extended sealing condition. The O-ring seals 52 are manufactured from a material having improved compression and wear properties, typically being manufactured from PTFE (polytetrafluoroethylene), which PTFE is typically impregnated with glass.

A second displacement controller in the form of a second crank arrangement 54 is provided for controlling the displacement of the tubular sealing members 50 between the inoperative retracted and extended sealing conditions during a compression cycle. The second crank arrangement 54 is configured to cause a tubular sealing member 50 to be displaced into the extended sealing condition between an outermost and inner compression member 20 when the outermost compression member 20.3 completes its compression stroke, thereby inhibiting return flow of pressurised gas to the outermost discrete volume 28.3 as the inner compression member 20.2 is displaced through its compression stroke. Although not shown, the second displacement controller can be in the form of a cam and cam follower arrangement. However, as shown in the Figures, the second crank arrangement 54 includes a crankshaft 56 and a plurality of connecting members 58 extending between and interconnecting the sealing members 50 and crankpins 60 of the crankshaft 54. In particular, the connecting members 58 extend between and interconnect corresponding crankpins 60 of the crankshaft 54 and opposing side regions 62 of the tubular sealing members 50, wherein the opposing side regions 62 of the tubular sealing members 50 extend away from a central axis thereof to allow sufficient space for the connecting members 58 to connect to and displace with the crankshaft 56 in use. It is to be appreciated that inhibiting return flow of pressurised gas prevents the outer compression member 20.2 or 20.3 from working any further on the same volume of gas during a compression cycle. Timing of the displacement of the sealing members 50 relative the compression members 20 is dependent on the relative position of the crankpins 60 of the crankshaft 56, the timing typically being dependent on relative angular orientation of the crankpins 60 and the crank radius.

A connecting means in the form of a chain connecting arrangement 64 is provided for connecting the first and second crank arrangements 32 and 54 for ensuring correct and constant timing and displacement of the respective crank arrangements 32 and 54 relative to each other. The chain connecting arrangement 64 includes sprockets 66 which are mounted on the crankshafts 34 and 56 respectively, and a chain (not shown) extending between and interconnecting the sprockets 66. The sprockets 66 are sized so as to cause the crankshaft 56 of the second crank arrangement 54 to rotate about twice as fast as the crankshaft 34 of the first crank arrangement 32. An inlet 68 is defined in the body 12 for allowing gas to enter the compression chamber 18. The inlet 68 is located relative the body 12 such that gas enters the compression chamber 18 from a region in the vicinity of the compression member completing the first compression stroke of the compression cycle, typically being the outermost compression member 20.3. Typically, the inlet 68 is located towards an end region of the body 12, typically being defined in the head portion 22 of the body 12. Further typically, the inlet 68 is located towards a periphery of the head portion 22, typically being defined in the head portion 22 towards a region nearest the walls 24 of the body 12. It is to be appreciated that the inlet 68 allows gas to enter the chamber 18 into the outermost discrete volume 28.3 once the outermost compression member 20.3 completes its compression stroke. A pair of inlets 68 are defined in the body 12 which are circumferentially spaced apart, typically being arranged opposite each other, for allowing gas to enter the compression chamber 18 via the outermost discrete volume 28.3.

An inlet valve 70 is mounted within the inlet 68 for inhibiting pressurised gas from exiting the compression chamber 18 via the inlet 68. The inlet valve 70 is in the form of a one-way valve, non-return valve or a check valve. The inlet valve 70 is configured to be displaced to an open condition for allowing gas to enter the outermost discrete volume 28.3 via the inlet 68 when the outermost compression member 20.3 completes its compression stroke and begins its suction stroke. The inlet valve 70 is biased towards a closed condition by a spring mechanism 72.

An outlet 74 is defined in the body 12 for allowing pressurised gas to exit the compression chamber 18. The outlet 74 is located in the region of the compression member 20 completing the final compression stroke of the compression cycle, typically being the innermost compression member 20.1. In particular, the outlet 74 is defined in the head portion 22 of the body 12 and is located generally centrally relative the compression chamber 18 for permitting pressurised gas to exit the compression chamber 18 from the innermost discrete volume 28.1 after the innermost compression member 20.1 has completed its compression cycle. An outlet valve 76 is mounted within the outlet 74 for inhibiting return flow of pressurised gas into the compression chamber 18. The outlet valve 76 is in the form of a one-way valve, non-return valve or check valve. The outlet valve 76 is configured to be displaced to an open condition for allowing pressurised gas to exit the compression chamber 18 via the outlet 74 when the innermost compression member 20.1 completes its compression cycle. The outlet valve 76 is biased towards the closed position by a spring mechanism 77 and by back pressure which has built up in a reservoir (not shown) to which the outlet 74 is connected.

A cooling system is provided for cooling the body 12 and compression arrangement 16 during compression of gas within the compression chamber 18. The cooling system includes a heat sink in the form of a plurality of fins 78 which are arranged on an outer surface of the body 12. In particular, the fins 78 extend substantially normally away from a side surface 80 of the body 12, which side surface 80 substantially surrounds the compression chamber 18. The cooling system further includes a fluid cooling means for cooling down the body 12 and compression arrangement 16 from within various parts thereof. The fluid cooling means includes a coolant (not shown), a plurality of cavities defined in the body 12 and compression arrangement 16, and a pump 82 for displacing the coolant through the plurality of cavities thereby cooling down the body 12 and compression arrangement 16. The coolant is in the form of an oil coolant. A first cavity 84 extends through the crankshaft 34 of the first crank arrangement 32 through the crankpins 38, connecting rods 36 and into the compression members 20 for allowing coolant to be pumped into and through the compression members 20. A second cavity 86 is located within the walls 24 of the body 12 for allowing coolant to be pumped therethrough. The second cavity 86 extends throughout the walls 24 of the body 12 for improving heat exchange with the coolant.

Typically, a sump 88 is provided for receiving coolant therein in use wherein an inlet pipe 90 extends between an operative lower region of the sump 88 and the pump 82 for allowing the pump 82 to receive coolant to be pumped through the cavities defined in the body 12 and compression member. Further, piping arrangements 92 extend between and interconnect the pump 82 and coolant inlets 94 defined in the walls 24 of the body 12 and crank arrangement 32.

It is, of course, to be appreciated that the compressor 10 in accordance with the invention is not limited to the precise constructional and functional details as hereinbefore described with reference to the accompanying drawings and which may be varied as desired.

Although only certain embodiments of the invention have been described herein, it will be understood by any person skilled in the art that other modifications, variations, and possibilities of the invention are possible. Such modifications, variations and possibilities are therefore to be considered as falling within the spirit and scope of the invention and hence form part of the invention as herein described and/or exemplified. It is further to be understood that the examples are provided for illustrating the invention further and to assist a person skilled in the art with understanding the invention and is not meant to be construed as unduly limiting the reasonable scope of the invention.

The inventor believes that the compressor in accordance with the present invention is advantageous in that it permits larger volumes of gas to be pressurised to higher pressures whilst consuming relatively low power when compared to conventional reciprocating compressors. This advantage results from the fact that multiple compression members are displaced through their respective compression strokes one at a time and that after a compression member completes its compression stroke, the compressed gas moves to an inner chamber for subsequent compression without being able to return to the preceding compression member. The inability of the gas to return to a preceding compression member effectively means that a compression member only compresses a given volume of gas once before receiving new gas to be compressed.

Claims

1. A compressor including: - a body defining a receiving zone therein; and a compression arrangement arranged within the receiving zone to define a compression chamber, the compression arrangement including a plurality of compression members which are displaceable relative each other and the receiving zone for compressing gas within the chamber in a stepwise manner.

2. A compressor as claimed in claim 1 wherein the body includes a head portion and walls extending therefrom to define the receiving zone, the head portion and walls of the body defining the compression chamber together with the compression arrangement.

3. A compressor as claimed in claim 1 or 2 wherein the receiving zone is sized, shaped and configured to receive the compression arrangement complementally therein.

4. A compressor as claimed in any one or more of the preceding claims wherein the compression members of the compression arrangement are sized, shaped and configured to be rotatably displaceable relative each other.

5. A compressor as claimed in any one or more of the preceding claims wherein the compression members of the compression arrangement are sized, shaped and configured to be reciprocally displaceable relative each other.

6. A compressor as claimed in any one or more of the preceding claims wherein the compression arrangement includes a first compression member having generally cylindrical shape.

7. A compressor as claimed in claim 6 wherein the compression arrangement includes a second compression member having a generally tubular shape defining a cylindrical receiving zone for receiving the first compression member complementally therein.

8. A compressor as claimed in claim 7 wherein the compression arrangement includes further generally tubular compression members so as to define a substantially nested compression arrangement.

9. A compressor as claimed in any one or more of the claims 6 to 8 wherein each subsequent compression member defines a progressively larger cylindrical receiving zone for receiving a preceding compression member complementally therein.

10. A compressor as claimed in any one or more of the preceding claims wherein the compression members are received coaxially within each other.

1 1. A compressor as claimed in any one or more of the claims 7 to 10 wherein an area of an annular compression face of an operatively outer compression member is larger than the surface area of an operatively inner compression member.

12. A compressor as claimed in any one or more of the preceding claims wherein the compression arrangement includes three compression members, an inner, pistonlike compression member, an intermediate tubular compression member arranged around the inner compression member and an outer tubular compression member arranged around the intermediate compression member.

13. A compressor as claimed in claim 12 wherein the ratio of the outer and intermediate areas is in the range of 3:1 to 5:1 .

14. A compressor as claimed in claim 12 or 13 wherein the ratio of the outer and inner areas is in the range of 6:1 and 10:1 .

15. A compressor as claimed in any one or more of the claims 12 to 14 wherein the ratio of the intermediate and inner areas is in the range of 2:1 to 5:1 .

16. A compressor as claimed in any one or more of the preceding claims wherein a first displacement controller is provided for controlling the displacement of the compression members relative the receiving zone and each other during a compression cycle.

17. A compressor as claimed in claim 16 wherein the first displacement controller is configured to ensure that the compression members are displaced through their respective compression strokes one at a time.

18. A compressor as claimed in claim 16 or 17 wherein the first displacement controller is configured to initiate the compression cycle via an outermost compression member which is followed by intermediate compression members and terminating the compression cycle via an innermost compression member.

19. A compressor as claimed in any one or more of the claims 16 to 18 wherein the first displacement controller is in the form of a crank arrangement including a crankshaft and a plurality of connectors extending between and interconnecting the compression members and crankpins of the crankshaft.

20. A compressor as claimed in claim 19 wherein the connector extending between and interconnecting the innermost compression member is in the form of a conventional connecting rod.

21 . A compressor as claimed in claim 19 wherein the connectors include a pair of connecting members for connecting tubular compression members to the crankshaft, the pair of connecting members extending between and interconnecting opposing side regions of the tubular compression members, respectively, and the crankshaft.

22. A compressor as claimed in any one or more of the claims 16 to 21 wherein a displacement means is provided for displacing the first displacement controller and for causing displacement of the compression members through the compression cycle thereby compressing gas within the compression chamber.

23. A compressor as claimed in any one or more of the preceding claims wherein communication means is provided for allowing fluid communication between discrete volumes within which each compression member is displaced, the discrete volumes being defined between compression faces of the respective compression members and the body.

24. A compressor as claimed in claim 23 wherein the communication means is in the form of gaps formed between an inner surface of the body and edge regions of the compression members, wherein the gaps are formed as the compression members are displaced relative each other through their respective compression cycles.

25. A compressor as claimed in claim 23 or 24 wherein a sealing arrangement is provided for sealing the discrete volumes within which each of the compression members are displaced at predetermined intervals during the compression cycle.

26. A compressor as claimed in claim 25 wherein the sealing arrangement is configured to seal the discrete volumes such that flow of pressurised gas is permitted to flow from one discrete volume to another whilst inhibiting return flow.

27. A compressor as claimed in claim 25 or 26 wherein the sealing arrangement includes a plurality of sealing members which are displaceably mounted on the head portion of the body.

28. A compressor as claimed in any one or more of the claims 25 to 27 wherein the sealing members are displaceable between an inoperable retracted condition wherein the sealing members are retracted away from the compression members thereby permitting flow of gas between discrete volumes and an extended sealing condition wherein the sealing members extend into the compression chamber thereby closing the gaps between the discrete volumes.

29. A compressor as claimed in claim 28 wherein the sealing members are configured to be displaced into the extended sealing condition at predetermined intervals so as to permit the flow of pressurised gas from an outer discrete volume to an inner discrete volume and inhibit return flow.

30. A compressor as claimed in any one or more of the claims 25 to 28 wherein the sealing members are in the form of generally tubular members which are dimensioned to slide into the compression chamber between the compression members thereby sealing off their respective discrete volumes from each other.

31 . A compressor as claimed in any one or more of the claims 25 to 30 wherein the sealing arrangement further includes a plurality of O-ring seals arranged between the compression members for inhibiting passage of pressurised gas out of the compression chamber and between the discrete volumes of the compression chamber when the sealing members are displaced towards the extended sealing condition.

32. A compressor as claimed in any one or more of the claims 25 to 31 wherein a second displacement controller is provided for controlling the displacement of the sealing members between the inoperative retracted and extended sealing conditions during a compression cycle.

33. A compressor as claimed in claim 32 wherein the second displacement controller is configured to cause a sealing member to be displaced into the extended sealing condition between an outermost and inner compression member when the outermost compression member completes its compression stroke, thereby inhibiting return flow of pressurised gas to the outermost discrete volume as the inner compression member is displaced through its compression stroke.

34. A compressor as claimed in claim 32 or 33 wherein the second displacement controller is in the form of a crank arrangement including a crank shaft and a plurality of connecting members extending between and interconnecting the sealing members and crankpins of the crankshaft.

35. A compressor as claimed in claim 34 wherein the connecting members extend between and interconnect corresponding crankpins of the crankshaft and opposing side regions of the tubular sealing members, wherein the opposing side regions of the tubular sealing members extend away from a central axis thereof to allow sufficient space for the connecting members to connect to and displace with the crankshaft in use.

36. A compressor as claimed in any one or more of the claims 19 to 35 wherein a connecting means is provided for connecting the first and second displacement controllers for ensuring correct and constant timing and displacement of the respective controllers relative to each other.

37. A compressor as claimed in claim 36 wherein the connecting means is in the form of a belt or chain connecting arrangement.

38. A compressor as claimed in any one or more of the preceding claims wherein an inlet is defined in the body for allowing gas to enter the compression chamber.

39. A compressor as claimed in claim 38 wherein the inlet is located towards a periphery of the head portion.

40. A compressor as claimed in claim 38 or 39 wherein a plurality of inlets are defined in the body which are circumferentially spaced apart from each other for allowing gas to enter the compression chamber via the outermost discrete volume.

41 . A compressor as claimed in any one or more of the claims 38 to 40 wherein an inlet valve is mounted within the inlet for inhibiting pressurised gas from exiting the compression chamber via the inlet.

42. A compressor as claimed in claim 41 wherein the inlet valve is configured to be displaced to an open condition for allowing gas to enter the outermost discrete volume via the inlet when the outermost compression member completes its compression stroke and begins its suction stroke.

43. A compressor as claimed in any one or more of the preceding claims wherein an outlet is defined in the body for allowing pressurised gas to exit the compression chamber.

44. A compressor as claimed in claim 43 wherein the outlet is defined in the head portion of the body and is located generally centrally relative the compression chamber for permitting pressurised gas to exit the compression chamber from the innermost discrete volume after the innermost compression member has completed its compression cycle.

45. A compressor as claimed in claim 43 or 44 wherein an outlet valve is mounted within the outlet for inhibiting return flow of pressurised gas into the compression chamber.

46. A compressor as claimed in claim 45 wherein the outlet valve is configured to be displaced to an open condition for allowing pressurised gas to exit the compression chamber via the outlet when the innermost compression members completes its compression cycle.

47. A compressor as claimed in any one or more of the preceding claims wherein a cooling system is provided for cooling the body and compression arrangement during compression of gas within the compression chamber.

48. A compressor as claimed in claim 47 wherein the cooling system includes a heat sink which is arranged on an outer surface of the body.

49. A compressor as claimed in claim 47 or 48 wherein the cooling system includes a fluid cooling means for cooling down the body and compression arrangement from within various parts thereof.

50. A compressor as claimed in claim 49 wherein the fluid cooling means includes a coolant, a plurality of cavities defined in the body and compression arrangement, and a pump for displacing the coolant through the plurality of cavities thereby cooling down the body and compression arrangement.

51 . A compressor as claimed in claim 50 wherein a first cavity extends through the crankshaft of the first displacement controller through the crankpins, connecting rods and into the compression members for allowing coolant to be pumped into and through the compression members.

52. A compressor as claimed in claim 50 or 51 wherein a second cavity is located within the walls of the body for allowing coolant to be pumped therethrough.