WO2007054910A2

WO2007054910A2 - Scroll type fluid machinery

Info

Publication number: WO2007054910A2
Application number: PCT/IB2006/054192
Authority: WO
Inventors: Enjiu Ke; Ji Ke
Original assignee: Ke, Enlong
Priority date: 2005-11-12
Filing date: 2006-11-10
Publication date: 2007-05-18
Also published as: CN1963205A; CN1963205B; WO2007054910A3

Abstract

Scroll type fluid machinery, in which orbiting scrolls (3A, 3B) are associated with stationary scrolls (2A, 2B) to form volume changing mechanisms (50A, 50B) to change the volumes of fluid. Orbiting units (40) are located between the two volume changing mechanisms to provide the functions of power transmission, centrifugal force balancing, thrust force cancellation and anti-self-rotation to the orbiting scrolls. Decompression chambers (39A, 39B) are located between the orbiting units and the two volume changing mechanisms. Liquid is injected into the volume changing mechanisms for sealing, lubricating and cooling functions. Some liquid may leak into the decompression chambers from the volume changing mechanisms, and is discharged. The orbiting scrolls are flexibly connected to thrust-canceling shafts (20) to enable themselves to have radial compliancy as well as tip compliancy. The compliancy and liquid injection technologies of the present invention can be also used to the machinery with single orbiting scroll.

Description

SCROLL TYPE FLUID MACHINERY

BACKGROUND OF THE INVENTION

[1] The present invention relates to scroll type fluid machinery, which can be used as compressors, vacuum pumps, expander machines, etc.

[2] The anti-self-rotating parallelogram mechanism has been adopted in scroll type fluid machinery with the advantages of being more stable and more reliable in operation, among many others, and can be used in oil-free applications. However, because of its fixed orbit radius, the radial and tip compliancy can not be achieved between the two engaging scrolls. Thus, high machining accuracy is required for scroll components, which increases the manufacturing cost for the machine.

[3] In US patents 4,300,875 and 5,752,816, flexible conjunction has been described for the anti-self-rotating parallelogram mechanism to achieve radial and tip compliant of orbiting scrolls. However, as mentioned in the patents, the forces acting on the driving crankshaft and the idle crankshaft are opposite in directions, because of the driving and driven relationship. Due to the flexible conjunction, a phase shift between the two kinds of crankshafts will be resulted. This leads to uncertain conditions in the operations of the machines, and thus causes the machines unable to work dependably all the time.

[4] The liquid injected into the volume changing mechanisms of scroll type fluid machinery can lubricate the surfaces of scrolls, and provide necessary conditions for the realization of radial and tip compliancy of orbiting scrolls. Moreover, the liquid injected also cools the operation temperature of the scroll type machinery effectively. Therefore, the liquid injection technique has been successfully applied at oil lubrication scroll compressors. It is well known that water is easy to be separated from compressed air, and so it is proposed to inject water into scroll compression chambers to improve the performance of oil-free scroll type compressor. The biggest challenge for water-injection oil-free scroll type machinery is how to keep water from contacting lubricants in the compressor economically and reliably. Up to now, there is no water- injection scroll compressor on the market.

[5] Double scroll type fluid machinery has got people' s attentions because of its many characteristics of excellence, including the thrust force cancellation among many others. Double scroll type fluid machinery with a plurality of orbiting units has been described in US Patent Application Publication 2004-0219047 Al, its orbiting units possess such functions as canceling thrust force, driving orbiting scrolls, balancing centrifugal force, and preventing orbiting scrolls' self rotation. This kind of arrangement can be used for oil-free compressors or vacuum pumps. The invention adopts anti-self-rotating parallelogram mechanisms with fixed orbiting radius.

SUMMARY OF THE INVENTION

[6] An object of the present invention is, by using the liquid injection and flexible conjunction techniques with anti-self-rotating parallelogram mechanisms, to allow scroll type fluid machinery to achieve the radial and tip compliancy of the orbiting scroll and to improve its efficiency and reliability, and to lower the manufacturing cost due to the strict requirement to scroll precision.

[7] According to one aspect of the present invention, the fluid machinery with double orbiting scrolls and fixed orbiting movement radius comprises two volume changing mechanisms comprising stationary scrolls and orbiting scrolls respectively. The two stationary scrolls are connected to a housing. At least two orbiting units are arranged between the two volume changing mechanisms. Each of the orbiting units comprises a rotating member rotatably supported on the housing and a thrust-canceling shaft rotatably and eccentrically supported in an eccentric through-hole in the rotating member. Each end of the thrust-canceling shaft is flexibly connected between the two orbiting scrolls. When one or more of the rotating members are driven, the orbiting scrolls orbit with respect to the stationary scrolls to change the fluid volumes continuously. The orbiting units provide many functions, such as transmitting driving force, balancing centrifugal force, canceling thrust force of the orbiting scrolls and preventing orbiting scrolls' self rotation. The peripheries of the rotating members can have the forms of pulleys, gears, sprockets, cylinders, or synchronous pulleys, etc. The varieties of the orbiting units in quantities and/or forms result in numerous configurations of the machinery to meet different application requirements.

[8] AU bearings of the orbiting units are isolated within the housing. A sealing interface is arranged between the housing and each of retainer rings fixed on the ends of thrust-canceling shafts.

[9] Tip seals are arranged between the outer region of the orbiting scrolls and the stationary scrolls. Two decompression chambers are formed between the orbiting units and the volume changing mechanisms. When the machine is in operation, liquid enter into the volume changing mechanisms to provide lubricating, sealing and/or cooling functions. One method for liquid entering is to inject pressurized liquid into compression chambers of the volume changing mechanisms, and another is to enter directly through suction ports of the volume changing mechanisms. The pressure in the decompression chambers can be equal approximately to the pressure of the work fluid source of the machine. The decompression chambers of water-injection oil-free air compressor can be connected with the atmosphere through the holes in the walls of the chambers, if the air is inhaled from the atmosphere. The chambers wherein the bearings reside can be connected with the decompression chambers to balance the pressures between the chambers. To keep the decompression chambers clean, filters can be installed in all the holes. The work pressure in surrounding region of the volume changing mechanisms is slightly lower than that of the work fluid source, therefore the liquid entered into the volume changing mechanisms does not normally leak out. While the machine is shut down, the check valves located at the discharge ports can prevent the pressurized fluid from flowing back, and the suction ports and a solenoid valve in the circuit of liquid injection shall also close. At this moment, the fluid pressure in the volume changing mechanisms is still high enough to cause the liquid to leak into the decompression chambers. But the leaked liquid does not have the energy to enter into the bearing chambers and contact bearing's lubrication agent, because the pressure in the bearing chambers is the same as that in the decompression chambers. The leaked liquid can be drained out through the holes at bottom of the decompression chambers, or accumulate within the decompression chambers temporarily, and be circulated back into the surrounding region of the volume changing mechanisms directly or indirectly when the compressor starts again.

[10] In dry scroll type fluid machinery, such as dry oil-free air compressor, neither sidewalls nor the tips of the scroll body shall contact each other; otherwise the scroll body will be worn out quickly. The liquid entered into the volume changing mechanisms is helpful in lubricating the volume changing mechanisms and in achieving the radial and tip compliancy of the orbiting scroll. In the present invention, the thrust-canceling shafts do not connect directly with the orbiting scrolls. The ends of the thrust-canceling shafts at the same side of the orbiting units are connected by an orbiting-driving linkage that is an integration of the linkage elements of the anti- self-rotating parallelogram mechanism. The two orbiting-driving linkages are connected to the two orbiting scrolls through flexible elements, respectively. When the scroll type machinery is in operation, the orbiting scroll tends to increase its orbiting radius under centrifugal force; this enables the orbiting scrolls to make radial compliancy movement in the direction of the engaging region. If there is some incompressible material in the volume changing mechanism, the orbiting scroll can make a radial conceding movement. Moreover, there are sealed chambers located between the orbiting-driving linkage and the orbiting scroll, and they are connected to compression region of the volume changing mechanisms. The orbiting scroll can make minuscule axial displacement relative to the orbiting-driving linkage. The force of the pressurized fluid within the sealed chambers can partially or entirely overcome the axial thrust force of the orbiting scroll exerted by the fluid in the volume changing mechanism to realize tip compliancy of the orbiting scroll.

[11] It is also applicable to use only one orbiting-driving linkage. But the double orbiting-driving linkages provide better rigidity. In the case that all the rotating members are driven with even load, the movement of the thrust-canceling shafts is steady, and thus the two orbiting-driving linkages become unnecessary. The thrust- canceling shafts can be flexibly connected to the orbiting scrolls directly. In the present invention, a means has been described to equalize the load of the rotating members, such as pulleys or gears.

[12] Using liquid injection alone can also improve the performance of the oil-free scroll type machinery to a certain extent. The compliancy and the liquid injection technologies of the present invention can also be used in other configurations of scroll type fluid machinery, including those with single orbiting scroll.

[13] The applications of the liquid injection and the radial and tip compliancy can reduce leakage, lower working temperature, increase energy efficiency, decrease noise level, improve operation reliability, reduce manufacturing and operation cost. The operation of the water-injection oil-free air compressor is nearly an isothermal compression process, and can provide more environment friendly compressed air.

[14] If water-injection oil-free scroll type machinery need being out of operation for a long time, the water remaining in the volume changing mechanisms should be discharged to keep the parts from rusting. This can be done by stopping water injection before the machine is shut off, because running the machine without water injection can help empty the water in the machine, and also raise temperature for the remaining water to vaporize. Brief Description of the Drawings

[15] Fig. 1 is a schematic sectional view of a water-injection oil-free scroll air compressor according to the first embodiment of the present invention.

[16] Fig. 2 is a schematic view of an orbiting-driving linkage subassembly of the machine shown in Fig. 1.

[17] Fig. 3 is a schematic sectional view of a water-injection oil-free scroll air compressor according to the second embodiment of the present invention.

[18] Fig. 4 is a sketch of a transmission system of the machine shown in Fig. 3.

[19] Fig. 5 is a schematic sectional view of a water-injection oil-free scroll air compressor according to the third embodiment of the present invention.

[20] Fig. 6 is a left view of the machine shown in Fig. 5, excluding the left volume changing mechanisms.

[21] Fig. 7 is a view zooming the conjunction between orbiting units and orbiting scrolls of the machine shown in Fig. 5.

[22] Figs. 8-10 are schematic sectional views of a part of the flexible element of thrust- canceling shaft and its collocation according to the embodiments of the present invention. [23] Fig. 11 is a schematic sectional view of a configuration of flexible thrust-canceling shaft according to the embodiments of the present invention.

[24] Fig. 12 is a schematic sectional view of a liquid-injection oil-free scroll compressor for natural gas according to the fourth embodiment of the present invention.

[25] Fig. 13 is a left sectional view of the machine shown in Fig. 12.

[26] Fig. 14 is a schematic sectional view and a schematic left view of an orbiting unit of the machine shown in Fig. 12.

[27] Fig. 15 is a system sketch drawing of a water-injection oil-free scroll air compressor according to the fifth embodiment of the present invention.

[28] Fig. 16 is a partial schematic sectional view of the compressor in the fifth embodiment.

Detailed description of invention

[29] Fig. 1 is a schematic sectional view of a water-injection oil-free scroll air compressor according to the first embodiment of the present invention. Fig. 2 is a schematic view of an orbiting-driving linkage subassembly of the compressor. As shown in Fig. 1, a volume changing mechanism 50 comprising an orbiting scroll 3 and a stationary scroll 2. The stationary scroll 2 is connected to a housing 1. A driving shaft 93 is rotatably supported on the housing 1. Three crankshafts 90, the driving shaft 93 and an orbiting-driving linkage 58 compose a series of parallelogram linkages which form an anti-self-rotating mechanism. Three bulge pins 99 on the orbiting-driving linkage 58 are connected with the orbiting scroll 3 through flexible elements 97, and form sealed chambers 96. The orbiting scroll 3 is supported by the orbiting-driving linkage 58 through three thrust washers 98. There exist a tip seal 95 and a sealed chamber 94 between the orbiting-driving linkage 58 and the orbiting scroll 3. With a tip seal 26, a decompression chamber 39 is formed between the orbiting scroll 3 and the housing 1, wherein holes 24 and 25 are connected to the atmosphere. To keep the decompression chamber 39 clean, filters should be installed in the holes 24 and 25. When operating, the driving shaft 93 drives the whole orbiting-driving linkage 58 to orbit with a fixed radius, which drives the orbiting scroll 3 through the flexible elements 97. Due to centrifugal force and fluid compression force, the orbiting scroll 3 is allowed to have minuscule radial displacement to achieve radial compliancy. Air enters the compressor through a filter 91 and a suction port 4, and is discharged through a discharge port 5 after compressed. Water is injected into the machine through inlets 27 to serve as a lubricating, sealing, and/or cooling agent. The water leaked from the volume changing mechanism 50 enters into the decompression chamber 39, and is discharged through hole 25. The sealed chambers 94 and 96 are connected to a compression region of the volume changing mechanism 50. The force of the pressurized air in the sealed chambers 96 and 94 can partially or entirely overcomes the axial thrust force of the orbiting scroll 3 exerted by the pressurized air within the volume changing mechanism 50 to realize the tip compliancy of the orbiting scroll 3. [30] Fig. 3 is a schematic sectional view of a water-injection oil-free scroll air compressor according to the second embodiment of the present invention. As shown in Fig. 3, a left volume changing mechanism 50A contains a left orbiting scroll 3A and a left stationary scroll 2A; a right volume changing mechanism 50B contains a right orbiting scroll 3B and a right stationary scroll 2B. The left and right stationary scrolls 2A and 2B are connected with a housing 1. Three orbiting units 40 are located between the left and right volume changing mechanisms 50A and 50B. Each of the three orbiting units 40 comprises a rotating member 10 rotatably supported on the housing 1 through two bearings 1 IA and 1 IB, and a thrust-canceling shaft 20 rotatably and eccentrically supported in the rotating member 10 by two bearings 14A and 14B. The two ends of the thrust-canceling shaft 20 respectively connect with the orbiting scrolls 3A and 3B through flexible elements 56A and 56B to allow the orbiting scrolls 3A and 3B to have minuscule radial displacement for radial compliancy. The periphery of each of the three rotating members 10 is in the form of a pulley. When the rotating members 10 are driven, the left and right orbiting scrolls 3 A and 3B orbit engage with the left a nd right stationary scrolls 2A and 2B, respectively. The volumes formed by the orbiting scrolls 2A and 2B and the corresponding stationary scrolls 3 A and 3B are continuously changed. Air enters into the left and right volume changing mechanisms 50A and 50B through filters 9 IA, 9 IB and suction ports 4A, 4B, and is discharged through discharge ports 5 A and 5B after compressed. Pressurized water is injected through inlets 27A and 27B into the left and right volume changing mechanisms 50A and 50B and to provide sealing, lubricating and cooling functions. Decompression chambers 39A and 39B are respectively located between the housing 1 and the left orbiting scroll 3 A and between the housing 1 and the right orbiting scroll 3B. The bearings 1 IA, 1 IB, 14A and 14B are located within bearing cavities 49 A and 49B. The decompression chambers 39A, 39B are separated from the left and right volume changing mechanisms 50A and 50B by tip seals 26A and 26B, respectively. The decompression chambers 39A and 39B and the bearing cavities 49A and 49B are separated by retaining rings 28A and 28B and labyrinth type seals 55A and 55B, and the decompression chambers 39 A and 39B are connected to the atmosphere through holes 25 A, 25B, 24 A, and 24B. To keep the cleanness of the decompression chambers 39 A and 39B, filters can be installed in the holes 25 A, 25B, 24 A and 24B. When the compressor is in operation, the pressures within the surrounding regions of the left and right volume changing mechanisms 50A and 50B are below the atmosphere pressure, and so the injected water does not leak out. When the compressor is shut down, there still remains compressed air in the left and right volume changing mechanisms 5OA and 5OB, although the discharge ports 5A, 5B and the inlets 27 A, 27B are closed. This causes the pressure within the surrounding regions to increase, and some water leaks into the decompression chambers 39A and 39B across the tip seals 26A and 26B. Because the pressures in the decompression chambers 39A, 39B and the bearing cavities 49 A, 49B are about the same, the water leaked into the decompression chambers 39A and 39B will not be able to enter into the bearing cavities 49 A and 49B. The bearing cavities 49A and 49B are connected to the decompression chambers 39A and 39B through outlet holes 29 A and 29B, respectively, to prevent water from accumulating in the bearing cavities 49 A and 49B, in case water enters into the cavities. The water entered into the decompression chambers 39A and 39B can be discharged through the holes 25 A and 25B. Another method to deal with the leaked water is to connect holes 25 A and 25B to the surrounding regions of the left and right volume changing mechanisms 50A and 50B or to the air intake paths after the filters 91 A and 9 IB. The water accumulated in the decompression chambers 39A and 39B will be circulated back into the compressor through the aforementioned channels.

[31] AU components contacting with water should be treated with effective corrosion- proof coating or anti-corrosion surface treatment, or should be made from corrosion- resistant material such as stainless steel or aluminum bronze, etc. The water used in the system should be purified.

[32] Fig. 4 is a sketch of a transmission system of the machine. As shown in Fig. 4,

1OA, 1OB, and 1OC (denoted as 10 in Fig. 3) are the rotating members - pulleys, and are driven in the counter-clockwise by a driving pulley 31 through a belt 33 that is tensioned by an idler pulley 32. When the compressor is in operation, the velocities of the belt 33 at the locations A, B and C are different, there exists a relationship of Va > Vb > Vc. To apply even driving force onto the pulleys 1OA, 1OB, and 1OC, and to reduce the relative slippage between the belt 33 and the pulleys 1OA, 1OB, and 1OC, the pitch radius of the pulleys 1OA, 1OB, and 1OC should have the following relationship: Ra> Rb> Rc. As an example, the radius can be calculated as follows:

[33] Ra : Rb : Rc = [1 + ( TO + 2T ) / ( AE )] : [1 + ( T0+ T ) / ( AE )] : [1 + TO / ( AE )]

[34] where T = 3.183 W/(n R), TO is the tension force on the loosing side of the belt, E is the elastic module of the belt material, A is the area of the belt cross-section, W is the power of the compressor, n is the rotation speed of the compressor, and R is the nominal pitch radius of the pulleys 1OA, 1OB and 1OC.

[35] Fig. 5 is a schematic sectional view of a water-injection oil-free scroll air compressor according to the third embodiment of the present invention. Fig. 6 is a left view of the machine, excluding the left volume changing mechanisms. Fig. 7 is the enlarged view of the connection between the rotating unit and the orbiting scroll. In this embodiment, the same constituent elements as those in the second embodiment are denoted by the same reference numerals, and a description thereof is omitted. This embodiment differs from the second embodiment in that the holes 25 A and 25B in the second embodiment are replaced by channels 53 A and 53B. The leaked water will be retained in the bottom of the decompression chamber 39A, 39B, and the water will be circulated back to the volume changing mechanisms 50A and 50B through the channels 53A and 53B. Outlet holes 29 A, 29B are located on the rotating members 10. Seals 55A and 55B are contact type seals. Inlets 38A and 38B are connected between the atmosphere and bearing cavities 49 A, 49B. Orbiting-driving linkages 58 A, 58B are connected, respectively, to the left and right ends of the three thrust-canceling shafts 20. The ends 21A and 21B on the thrust-canceling shafts 20 are connected to the left and right orbiting scrolls 3 A and 3B through flexible elements 97 A and 97B, and are axially contacted the left and right orbiting scrolls 3 A and 3B through thrust washers 98A and 98B, respectively. Sealed chambers 48A, 48B formed between the ends 21A, 2 IB and the left and right orbiting scrolls 3 A, 3B are connected to compression regions of the volume changing mechanisms 50A and 50B. When the machine is in operation, the left and right orbiting scrolls 3 A, 3B make minuscule radial displacement to achieve radial compliancy, under the action of centrifugal force and the fluid pressure. The force of the pressurized air in the sealed chambers 48A, 48B can partly or entirely overcome the axial thrust force of the orbiting scrolls 3 A, 3B exerted by the pressurized air in the volume changing mechanism 50A, 50B, and thus the tip compliancy of the orbiting scrolls 3 A, 3B can be realized. The radial displacement of the orbiting scrolls 3A, 3B should be controlled properly. As shown in Fig. 7, the thickness of the flexible element 97A is donated by t, the radial clearance between the end 21 A and the orbiting scroll 3 A is donated by s, which is the maximum displacement and should be smaller than t.

[36] When all the orbiting units are evenly driven and the loads on the orbiting scrolls are also even, some or all of the orbiting-driving linkages described in the third embodiment can be omitted. Under this condition, the aforementioned flexible elements for radial compliancy of orbiting scrolls can have different position arrangements and different forms. As shown in Figs. 8-11, flexible elements differ in arrangements and forms. In the figures, the same constituent elements as those in the third embodiment are denoted by the same reference numerals.

[37] In Fig. 8, flexible elements 56A and 56B are arranged between the inside ring of bearing 14A, 14B and the thrust-canceling shaft 20.

[38] In Fig. 9, flexible elements 56A and 56B are arranged between the outer ring of bearing 14A, 14B and the rotating member 10.

[39] In Fig. 10, flexible elements 56A and 56B are arranged between the thrust- canceling shaft 20 and the left and right rotating scrolls 3 A, 3B.

[40] In Fig. 11, the thrust-canceling shaft 20 is made in a flexible structure form.

[41] The above structure all allow orbiting scrolls to make minuscule radial displacement to achieve their radial compliancy, under the action of the centrifugal force and the fluid pressure.

[42] Fig. 12 is a schematic sectional view of a liquid-injection oil-free scroll compressor for natural gas according to the fourth embodiment of the present invention. Fig. 13 is a schematic left sectional view of the machine; Fig. 14 is a schematic sectional view and the left view of an orbiting unit of the machine. In this embodiment, the same constituent elements as those in the third embodiment are denoted by the same reference numerals, and a description thereof is omitted. This embodiment differs from the third embodiment in that this embodiment adopts the liquid injection technology only. The suction ports 4A, 4B are connected to a gas source 54 through filters 57A and 57B. To equalize the pressure in the gas source 54 to that of the decompression chambers 39A, 39B, and the bearing cavities 49 A, 49B, holes 24A, 24B and inlets 38A, 38B are connected to each other, and then to the gas source 54 through a filter 56. AU the rotating members 10 are in the form of gears, and all engage with an idler gear 35 that is rotatably supported by the housing 1. A driving gear 36 engages with one of the three rotating members 10 to drive the whole compressor. Each of the three rotating members 10 comprises an outer ring 102, an inner ring 103 and a flexible coupling 101. The outer ring 102 can make a small angular movement relative to the inner ring 103 in the circumferential direction, but the movement in the radial or axis directions is constrained. The driving gear 36 engages with the outer ring 102 of a rotating member 10 to transfer power to the outer rings 102 of the two other rotating members 10 through the idler gear 35. The three outer rings 102 transfer moment to the corresponding inner rings 103 through the flexible couplings 101 to drive the left and right orbiting scrolls 3 A, 3B of the compressor. The loads on the three rotating members 10 are even when using the flexible couplings 101.

[43] Fig. 15 is a system sketch drawing of a water-injection oil-free scroll air compressor according to the fifth embodiment of the present invention. Fig. 16 is a partial schematic sectional view of the compressor in the embodiment. As show in Figs. 15 and 16, a motor 216 provides the driving power to an air end 204. Air passes a filter 203 and an inlet valve 221 to enter into volume changing mechanism 50 formed by orbiting scroll 3 and stationary scroll 2 of the air end 204. Compressed air and water pass a check valve 215 and enter into a water-air separator 205, and are separated. The separated air is discharged through a minimum pressure check valve 208, and the separated water pass through a cooler 212, a solenoid vale 213, a filter 214 and inlets 27, and enters into the air end 204 for cooling, sealing and lubricating functions. [44] When the machine stops, the water in the decompression chamber 39 and the volume changing mechanisms 50 is discharged through holes 25 and 125, and accumulates in a kettle 220. When the air end 204 starts the next time, the water remaining in the kettle 220 can be circulated back into the air end 204. To keep appropriate quantity of water in the system, a level switch 206 controls a valve 202 to supply water from a pure water source 201 and a valve 211 to discharge excessive water as well. It should be avoided for the water to remain in the air end 204, if the machine needs stopping for a long time. A control device 217 turns off the solenoid valve 213 of the water injection loop for an appropriate period before the motor 216 stops. The air end 204 continues running without water injection in order to remove the water from the air end 204 and to raise the temperature properly to vaporize the remaining water.

[45] In case power supply is interrupted suddenly, it is impossible for the system to complete the aforementioned stopping procedure. In such a time, the system can perform the following two operations: 1) turning the compressed air in the water-air separator 205 back into the air end 204 through a solenoid valve 209 to drive the air end 204 to rotate in the reverse direction so that the water in the air end 204 can be expelled out; 2) using a battery of the control device 217 to supply power to a DC motor 210 to drive the air end 204 through a clutch 222 at a low speed to discharge the water, and to increase the body temperature appropriately to vaporize the remaining water .These two operations can be performed individually or alternatively.

[46] Although in the foregoing embodiments, the liquid used for sealing, lubricating and/or cooling is water, the present invention is not necessarily limited to water, and it can use other liquids.

[47] Although in the foregoing embodiments, the present invention has been described using scroll compressors as examples of scroll type fluid machinery, the present invention is not necessarily limited to the scroll compressor, but can also be applied to other scroll type fluid machinery, such as vacuum pumps, refrigerant compressors and expanders, etc.

[48] Although in the foregoing embodiments, the scroll type fluid machinery comprises two volume changing mechanisms having the same function, the present invention is not necessarily limited to the described usages. For example, one of the two volume changing mechanisms can be used as a compression mechanism while the other used as an expansion mechanism.

[49] Although a description for some common mechanical devices, such as balancer, shaft seal, alignment pin, etc, is omitted in the foregoing embodiments, the present invention is not limited from their application.

Claims

[ 1 ] L A scroll type fluid machinery comprising : a. a first volume changing mechanism comprising a first stationary scroll and a first orbiting scroll; b. a housing connecting with said first stationary scroll; c. an anti-self-rotating parallelogram mechanism and a driving device for said first orbiting scroll; wherein a first decompression chamber is formed between said first orbiting scroll and said housing; when the machinery is in operation, liquid enters into said first volume changing mechanism to achieve lubricating, sealing and/or cooling functions; the liquid leaked from said first volume changing mechanism enters into said first decompression chamber, and is discharged.

[2] 2. A scroll type fluid machinery according to claim 1, wherein an orbiting- driving linkage constitutes the linkages of said anti-self-rotating parallelogram mechanism, driven by said driving device, and connected to said first orbiting scroll through flexible elements; said first orbiting scroll is driven by said orbiting-driving linkage ?and can make radial compliancy; at least one sealed chamber exists between said orbiting-driving linkage and said first orbiting scroll; said sealed chamber connects to the compression region of said first volume changing mechanism to realize tip compliancy of said first orbiting scroll.

[3] 3. A scroll type fluid machinery according to claim 1, wherein a. a second volume changing mechanism comprising a second stationary scroll and a second orbiting scroll; b. said housing connecting with said first and second stationary scrolls; c. said anti-self-rotating parallelogram mechanism and said driving device comprising plurality of orbiting units provided between said first and second orbiting scrolls, each of said orbiting units comprising: a) a rotating member being rotatably supported by said housing; b) a thrust-canceling shaft being connected to said first and second orbiting scrolls, said thrust-canceling shaft further being eccentrically and rotatably supported in said rotating member; d. a second decompression chamber and said first decompression chamber formed between said orbiting units and said first, second volume changing mechanisms where liquid enters to provide lubricating, sealing and/or cooling functions; the liquid leaked from said first and second volume changing mechanisms enters into said first and second decompression chambers, and is discharged.

[4] 4. A scroll type machinery according to claim 3, wherein each of said orbiting units is supported by said housing through a first bearing group; each of said thrust-canceling shafts is supported in said rotating member through a second bearing group; a retaining ring and a sealing interface are mounted on each end of said thrust-canceling shafts; said retaining rings and said sealing interface provide sealing functions between said first and second bearing groups and said first and second decompression chambers.

[5] 5. A scroll type machinery according to claim 3, wherein said first and second decompression chambers are connected with work fluid source to equalize the pressure in said first and second decompression chambers with that in said work fluid source.

[6] 6. A scroll type machinery according to claim 3, 4 or 5, wherein through holes on said first and second decompression chambers are used to discharge said leaked liquid.

[7] 7. A scroll type machinery according to claim 3, 4 or 5, wherein said first and second decompression chambers are connected with intake region of said first and second volume changing mechanisms to circulate said leaked liquid back to said first and second volume changing mechanisms.

[8] 8. A scroll type machinery according to claim 3, wherein each end of said thrust- canceling shafts is connected to said first or said second orbiting scroll through a flexible element to realize radial compliancy of said first and second orbiting scrolls.

[9] 9. A scroll type machinery according to claim 3, 4 or 5, wherein said thrust- canceling shafts possess flexible structure form to realize the radial compliancy of said first and second orbiting scrolls.

[10] 10. A scroll type machinery according to claim 8, wherein at least one orbiting- driving linkage is attached to the end of said trust-canceling shafts.

[11] 11. A scroll type machinery according to claim 8 or 10, wherein sealed chambers are formed at the conjunctions of said thrust-canceling shafts and said first, second orbiting scrolls with said flexible elements; said sealed chambers are connected to pressure area of said first and second volume changing mechanisms to realize the tip compliancy of said first and second orbiting scrolls.

[12] 12. A scroll type machinery according to claim 3, 4, 5 or 8, wherein said rotating members consist first, second, and third pulleys driven with a belt; the tightening side of said belt attached to said first pulley, the loose side of said belt attached to said third pulley, where the relationship of nominal pitch radius (Rl, R2, R3) of said first, second, third pulleys is defined as: Rl > R2 > R3.

[13] 13. A scroll type machinery according to claim 3, 4, 5 or 8, wherein said rotating member comprises an inner ring, an outer ring and a flexible coupling; a small relative angular movement can be made between said inner ring and said outer ring; said outer ring and said inner ring can achieve torque transmission with said flexible coupling.

[14] 14. A scroll type fluid machinery system comprising: a. a scroll type fluid machinery; b. a primary motor and a driving device; c. a liquid injection system; d. a control device; wherein, when said scroll type fluid machinery needs stopping for a long time, said control device can stop said liquid injection before shutting down said scroll type fluid machinery to discharge the liquid remaining in said scroll type fluid machinery.

[15] 15. A scroll type fluid machinery system according to claim 14, wherein a standby motor, when the energy source for said primary motor being interrupted, uses a standby energy source to drive said scroll type fluid machinery to discharge said liquid remaining in said scroll type fluid machinery.

[16] 16. A scroll type fluid machinery system according to claim 14, wherein pressured fluid stored in a container, when the energy sources for said primary motor being interrupted, is able to flow back into said scroll type fluid machinery, and to drive said scroll type fluid machinery to discharge said liquid remaining in said scroll type fluid machinery.