Abstract:
Disclosed is an exhaust valve ( 10 A,  10 B,  10 C,  10 D,  10 E), comprising a valve body ( 12 ), wherein the first end of the valve body is provided with a fluid inlet ( 15 ); the sidewall of the valve body is provided with at least one fluid outlet ( 17 ) in fluid communication with the fluid inlet ( 15 ) and a valve flap ( 20 ) for opening or closing the fluid outlet; and the axis direction of the fluid outlet ( 17 ) is inclined relative to that of the fluid inlet ( 15 ). Further disclosed is a compressor comprising the above-mentioned exhaust valve. The exhaust valve has a relatively low fluid resistance, and is able to significantly reduce the pressure drop in the compressor due to the exhaust valve, so that the operating efficiency of the compressor is increased.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priorities to Chinese Patent Application No. 201210341677.2 titled “DISCHARGE VALVE AND COMPRESSOR INCLUDING THE SAME”, filed with the Chinese State Intellectual Property Office on Sep. 14, 2012, and Chinese Patent Application No. 201220470547.4 titled “DISCHARGE VALVE AND COMPRESSOR INCLUDING THE SAME” filed with the Chinese State Intellectual Property Office on Sep. 14, 2012, the entire disclosures of which are incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    The application relates to a discharge valve and a compressor including the discharge valve. 
       BACKGROUND 
       [0003]    As shown in  FIG. 1 , a conventional scroll compressor  100  generally includes a housing  110 , a top cover  112  arranged at one end of the housing  110 , a bottom cover  114  arranged at the other end of the housing  110 , and a partition plate  116  arranged between the top cover  112  and the housing  110  for separating an inner space of the compressor into a high pressure side and a low pressure side. The high pressure side is formed between the partition plate  116  and the top cover  112 , and the low pressure side is formed among the partition plate  116 , the housing  110  and the bottom cover  114 . An inlet connector (not shown) is arranged at the low pressure side for suctioning fluid, and an outlet connector  119  is arranged at the high pressure side for discharging the compressed fluid. A motor  120  including a stator  122  and a rotor  124  is arranged in the housing  110 . A driving shaft  130  is provided in the rotor  124  to drive a compressing mechanism including a non-orbiting scroll  150  and an orbiting scroll  160 . The orbiting scroll  160  includes an end plate  164 , a hub  162  formed at one side of the end plate, and a spiral blade  166  formed at the other side of the end plate. The non-orbiting scroll  150  includes an end plate  154 , a spiral blade  156  formed at one side of the end plate, and a discharge port  152  formed at a substantially central position of the end plate. The orbiting scroll  160  is supported at one side by a main bearing housing  140 , and the driving shaft  130  is also supported at one end by the main bearing housing  140 . An eccentric crankpin  132  is provided at one end of the driving shaft  130 , and an unloading liner  142  is provided between the eccentric crankpin  132  and the hub  162  of the orbiting scroll  160 . Being driven by the motor  140 , the orbiting scroll  160  orbits relative to the non-orbiting scroll  150  (i.e., the central axis of the orbiting scroll  160  rotates about the central axis of the non-orbiting scroll  150 , however, the orbiting scroll  160  itself cannot rotate about its central axis) to compress the fluid. The fluid compressed by the non-orbiting scroll  150  and the orbiting scroll  160  is discharged to the high pressure side via the discharge port  152 . A one-way valve or a discharge valve  170  is provided at the discharge port  152  in order to prevent the fluid at the high pressure side from flowing back to the low pressure side via the discharge port  152  under certain circumstances. 
         [0004]      FIG. 2  shows an exploded perspective view of a conventional discharge valve  170 . As shown in  FIG. 2 , the discharge valve  170  includes a substantially annular valve seat  172  (a valve port  175  is provided in the valve seat  172 ), at least one valve flap  174  arranged at the valve seat  172  for opening or closing the valve port, a valve stop  176  for preventing the valve flap from being excessively deformed, and a pin  179  for fixing the above components together. The discharge valve  170  with the above construction is fixed in the hub  153  in the vicinity of the discharge port  152  of the non-orbiting scroll  150  (shown in  FIG. 4 ) via a holder  178  (see  FIG. 4 ).  FIG. 3A  shows the discharge valve  170  in a closed state, and  FIG. 3B  shows the discharge valve  170  in an opened state. 
         [0005]    In the conventional discharge valve  170  shown in  FIGS. 2 to 4 , due to the specific position relationship of the valve seat  172 , the valve stop  176  and the holder  178  relative to the discharge port  152  of the non-orbiting scroll  150 , when the compressed fluid is discharged from the discharge port  152  to the high pressure side, the flowing direction of the fluid is turned by substantially 90 degrees each time at portions A, B, C and D shown in  FIG. 4 . An upper surface of the valve seat  172  is perpendicular to an axis direction of the discharge port  152  (or the valve port  175  in the valve seat  172 ). Thus, when the valve flap  174  opens, the fluid has to be turned by substantially 90 degrees (at position A). Next, since an axis direction of a flowing passage in the valve stop  176  is substantially parallel to the axis direction of the discharge port  152 , the fluid flowing out of the valve flap  174  along substantially a horizontal direction has to be turned again by substantially 90 degrees (at position B). Finally, the fluid flowing out of the flowing passage of the valve stop  176  along substantially a vertical direction is directed by the holder  178  and tends to flow towards an area which has the smallest pressure. Hence, the fluid is then turned by substantially 90 degrees each time at substantially positions C and D. These turns significantly increase the flowing resistances of the fluid. Hence, a significant pressure drop is caused from the discharge port  152  to the high pressure side. This kind of pressure drop may result in a reduced efficiency and an increased energy consumption of the compressor. 
         [0006]    Therefore, there is a need for a discharge valve which can effectively reduce the flowing resistance. 
       SUMMARY 
       [0007]    An object of one or more embodiments of the present application is to provide a discharge valve which can reduce the flowing resistance. 
         [0008]    Another object of one or more embodiments of the present application is to provide a discharge valve which has a low cost and a simple structure. 
         [0009]    Still another object of one or more embodiments of the present application is to provide a compressor which has a high operating efficiency. 
         [0010]    For achieving one or more of the above objects, a discharge valve is provided according to an aspect of the present application, which includes a valve body. A first end of the valve body is provided with a fluid inlet. A side wall of the valve body is provided with at least one fluid outlet in fluid communication with the fluid inlet, and a valve flap for opening or closing the fluid outlet. An axis direction of the fluid outlet is inclined relative to an axis direction of the fluid inlet. 
         [0011]    Preferably, an angle between the axis direction of the fluid outlet and the axis direction of the fluid inlet is greater than 0 degree and less than or equal to 90 degrees. 
         [0012]    Preferably, the angle between the axis direction of the fluid outlet and the axis direction of the fluid inlet is greater than or equal to 30 degrees and less than or equal to 80 degrees. 
         [0013]    Preferably, the angle between the axis direction of the fluid outlet and the axis direction of the fluid inlet is greater than or equal to 70 degrees and less than or equal to 80 degrees. 
         [0014]    Preferably, an angle between a plane in which the valve flap is located when the valve flap closes the fluid outlet and the axis direction of the fluid inlet is greater than or equal to 0 degree and less than 90 degrees. 
         [0015]    Preferably, the angle between the plane in which the valve flap is located when the valve flap closes the fluid outlet and the axis direction of the fluid inlet is greater than or equal to 10 degrees and less than or equal to 60 degrees. 
         [0016]    Preferably, the angle between the plane in which the valve flap is located when the valve flap closes the fluid outlet and the axis direction of the fluid inlet is greater than or equal to 10 degrees and less than or equal to 20 degrees. 
         [0017]    Preferably, a point of the valve flap fixed to the valve body is located between the fluid outlet and the fluid inlet in an axial direction of the valve body. 
         [0018]    Preferably, the discharge valve further includes a valve stop for limiting a displacement of the valve flap. 
         [0019]    Preferably, a point of the valve stop fixed to the valve body is located between the fluid outlet and the fluid inlet in the axial direction of the valve body. 
         [0020]    Preferably, two or three or four fluid outlets are provided, and each of the fluid outlets is provided with the valve flap. 
         [0021]    Preferably, the fluid outlets are centrosymmetrically arranged at equal angular intervals about the axis direction of the fluid inlet. 
         [0022]    Preferably, the fluid outlets are arranged at the same height along the axis direction of the fluid inlet. 
         [0023]    Preferably, a second end of the valve body includes a piston. 
         [0024]    Preferably, the discharge valve further includes a sleeve fitted with the valve body, wherein the fluid outlet is located in a cavity of the sleeve. 
         [0025]    Preferably, a side wall of the sleeve is formed with at least one opening. 
         [0026]    Preferably, one end of the sleeve is formed with the piston. 
         [0027]    According to another aspect of the present application, a compressor is provided, which includes the above described discharge valve. 
         [0028]    Preferably, the compressor is a scroll compressor, and the scroll compressor includes a non-orbiting scroll and an orbiting scroll. The first end of the valve body of the discharge valve is fixed at a discharge port of the non-orbiting scroll. 
         [0029]    Preferably, the first end of the valve body is fixed at the discharge port by screw-thread fit or pressing fit. 
         [0030]    Preferably, the compressor further includes a capacity modulation mechanism configured to modulate the capacity of the compressor by adjusting an axial displacement of the non-orbiting scroll, wherein the valve body of the discharge valve constitutes a portion of the capacity modulation mechanism. 
         [0031]    Preferably, the capacity modulation mechanism further includes a capacity modulation cylinder block, and the piston on the valve body of the discharge valve is configured to be movable in the capacity modulation cylinder block. 
         [0032]    Preferably, the compressor further includes a capacity modulation mechanism configured to modulate the capacity of the compressor by adjusting the axial displacement of the non-orbiting scroll, wherein the sleeve of the discharge valve constitutes a portion of the capacity modulation mechanism. 
         [0033]    Preferably, the capacity modulation mechanism further includes a capacity modulation cylinder block, and the piston on the sleeve of the discharge valve is configured to be movable in the capacity modulation cylinder block. 
         [0034]    Preferably, the capacity modulation cylinder block is in fluid communication with an external pressure source via an electromagnetic valve. 
         [0035]    Preferably, the compressor is one of a scroll compressor, a piston compressor, a screw rod compressor, a centrifugal compressor, and a rotor compressor. 
         [0036]    The discharge valve and the compressor according to one or more embodiments of the present application have the following advantages. 
         [0037]    In a discharge valve according to an embodiment of the present application, the valve body includes a fluid inlet and at least one fluid outlet, and an axis direction of the fluid outlet is inclined with respect to an axis direction of the fluid inlet. Compared with a conventional discharge valve in which the axes of the fluid inlet and the fluid outlet are overlapped with or parallel to each other (as shown in  FIGS. 2 to 4 ), the configuration in which the axis direction of the fluid outlet is inclined (here, the inclination includes the situation in which the two axes are perpendicular to each other) with respect to the axis direction of the fluid inlet according to the embodiments of the present application can reduce the flowing resistance of the fluid, thereby reducing the pressure drop caused by the discharge valve, since flow of the fluid is not required to be turned by an angle of 90 degrees for many times. In addition, since only the fluid inlet and the fluid outlet are arranged in the valve body, and a valve flap is arranged on the fluid outlet, the discharge valve according to the embodiments of the present application may have a very simple structure, and thus the manufacturing cost is reduced. 
         [0038]    In the discharge valve according to a further embodiment of the present application, an angle formed between the axis direction of the fluid outlet and the axis direction of the fluid inlet may be greater than 0 degree and less than or equal to 90 degrees, preferably, greater than or equal to 30 degrees and less than or equal to 80 degrees, and more preferably, greater than or equal to 70 degrees and less than or equal to 80 degrees. In other words, an angle between a plane in which the valve flap is located when the valve flap closes the fluid outlet and the axis direction of the fluid inlet may be greater than or equal to 0 degree and less than 90 degrees, preferably, greater than or equal to 10 degrees and less than or equal to 60 degrees, and more preferably, greater than or equal to 10 degrees and less than or equal to 20 degrees. Compared with the conventional discharge valve shown in  FIGS. 2 to 4 , the discharge valve with the angle in the above ranges, particularly, in the more preferred ranges may bring a significant improvement of the operating efficiency of the compressor due to the reduction of the flowing resistance. As has been practically tested, the operating efficiency of the compressor may be increased over 3% to 6% in various operating conditions. 
         [0039]    In a discharge valve according to a further embodiment of the present application, a point of the valve flap fixed to the valve body is located between the fluid outlet and the fluid inlet. In other words, the valve flap is arranged to be opened in a direction which allows the flowing resistance of the fluid to be minimized. Thus, the flowing resistance in the discharge valve can be further reduced. 
         [0040]    In a discharge valve according to a further embodiment of the present application, the discharge valve may further include a valve stop for limiting a displacement of the valve flap. Hence, the probabilities of plastic deformation and fatigue failure of the valve flap can be reduced, and the reliability of the discharge valve can be increased. Furthermore, a point of the valve stop fixed to the valve body is also located between the fluid outlet and the fluid inlet, that is, the valve stop may be fixed to the valve body at the same position as the valve flap. Thus, the flowing resistance caused by the presence of the valve stop is reduced. 
         [0041]    In the discharge valve according to a further embodiment of the present application, a first end of the valve body may be fixed at the discharge port of the compressing mechanism of the compressor by screw-thread fit or pressing fit. Since the valve body may be directly fixed at the discharge port, the holder for fixing the conventional discharge valve shown in  FIGS. 2 to 4  is omitted, thereby further reducing the flowing resistance caused by the holder. 
         [0042]    In the discharge valve according to a further embodiment of the present application, two or three or four fluid outlets may be provided, and each of the fluid outlets is provided with the valve flap. Further, these fluid outlets may be centrosymmetrically arranged at equal angular intervals about the axis direction of the fluid inlet. In addition, these fluid outlets may further be arranged at the same height in the axis direction of the fluid inlet. Adopting such configuration may increase the total cross sectional area of the fluid outlets to further reduce the pressure drop. In addition, due to the symmetric arrangement of the fluid outlets, the pressure balance at the high pressure side may be more effectively achieved, and the noise and pressure fluctuation may be more effectively reduced, thereby ensuring more stable operation of the compressor. 
         [0043]    The compressor according to an embodiment of the present application adopts the above discharge valve and thus has the above advantages brought by the discharge valve. 
         [0044]    In the compressor according to a further embodiment of the present application, the compressor may be a scroll compressor. The scroll compressor may include a non-orbiting scroll and an orbiting scroll, and the discharge valve is fixed at a discharge port of the non-orbiting scroll. In particular, in the case of the compressor with a variable capacity, the compressor may further include a capacity modulation mechanism configured to modulate the capacity of the compressor by adjusting an axial displacement of the non-orbiting scroll, and the valve body of the discharge valve or a sleeve fitted with the valve body may constitute a portion of the capacity modulation mechanism. More specifically, the capacity modulation mechanism may include a capacity modulation cylinder block, and the second end of the valve body of the discharge valve or the sleeve of the discharge valve may include a piston which is movable in the capacity modulation cylinder block. Since the first end of the valve body is fixedly connected to the discharge port of the non-orbiting scroll, and the piston on a second end of the valve body or the piston on the sleeve is axially movable in the capacity modulation cylinder block, the discharge valve may be driven to move axially by controlling the pressure in the capacity modulation cylinder block, thus driving the non-orbiting scroll to move axially to realize the capacity modulation function of the compressor. Since the discharge valve and the member (e.g., the piston) for controlling the capacity of the compressor are integrally configured, the number of the components is reduced and the assembling process of the compressor is simplified, thereby reducing the manufacturing cost of the compressor. 
         [0045]    In the compressor according to a further embodiment of the present application, the compressor may be one of a scroll compressor, a piston compressor, a screw rod compressor, a centrifugal compressor, and a rotor compressor. In other words, the discharge valve according to the embodiment of the present application is applicable in various compressors, and has a good universality. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0046]    Features and advantages of one or more embodiments of the present application can be understood more readily with reference to the description in conjunction with the drawings in which: 
           [0047]      FIG. 1  is a longitudinal sectional view of a conventional scroll compressor; 
           [0048]      FIG. 2  is a perspective view of the conventional discharge valve in  FIG. 1 ; 
           [0049]      FIGS. 3A and 3B  are schematic views of the discharge valve shown in  FIG. 2  in a closed state and an opened state, respectively; 
           [0050]      FIG. 4  is an enlarged view showing the vicinity of a discharge port of a non-orbiting scroll of the scroll compressor shown in  FIG. 1 ; 
           [0051]      FIG. 5  shows a longitudinal sectional view of a scroll compressor according to an embodiment of the present application; 
           [0052]      FIG. 6  shows a perspective view of a discharge valve according to a first embodiment of the present application; 
           [0053]      FIG. 7  shows a sectional view of the discharge valve according to the first embodiment of the present application; 
           [0054]      FIGS. 8A and 8B  are a front view and a bottom view of a discharge valve according to a second embodiment of the present application, respectively; 
           [0055]      FIGS. 9A and 9B  are a front view and a bottom view of a discharge valve according to a third embodiment of the present application, respectively; 
           [0056]      FIGS. 10A and 10B  are an exploded perspective view and an assembling perspective view of a discharge valve according to a fourth embodiment of the present application, respectively; and 
           [0057]      FIG. 11  is a longitudinal sectional view of a discharge valve according to a fifth embodiment of the present application. 
       
    
    
     DETAILED DESCRIPTION 
       [0058]    The following description of the preferred embodiments is only illustrative rather than limiting to the present application and application or use thereof. 
         [0059]    The basic configuration and operation process of the conventional scroll compressor  1  has been described with reference to  FIGS. 1 to 4  in the part of Background.  FIG. 5  shows a scroll compressor  100 A according to an embodiment of the present application. The scroll compressor  100 A according to the present application adopts various discharge valves  10 A,  10 B,  10 C and  10 D shown in  FIGS. 6 to 10B  to replace the conventional discharge valve  170  shown in  FIG. 1 . In particular, the like reference signs in  FIG. 1  are used in  FIG. 5  to indicate the like components as shown in  FIG. 1 , and thus the description of configuration of these like components will not be repeated. 
         [0060]    As shown in  FIG. 5 , a scroll compressor  100 A according to an embodiment of the present application includes a housing  110 , a top cover  112  arranged at one end of the housing  110 , a bottom cover  114  arranged at the other end of the housing  110 , and a partition plate  116  arranged between the top cover  112  and the housing  110  to separate an inner space of the compressor into a high pressure side and a low pressure side. The high pressure side is formed between the partition plate  116  and the top cover  112 , and the low pressure side is formed among the partition plate  116 , the housing  110  and the bottom cover  114 . An inlet connector  118  for suctioning fluid is arranged at the low pressure side, and an outlet connector  119  for discharging the compressed fluid is arranged at the high pressure side. 
         [0061]    A discharge valve  10 A according to a first embodiment of the present application is provided at a discharge port  152  of a non-orbiting scroll  150 . As shown in  FIGS. 6 and 7 , the discharge valve  10 A may include a valve body  12 . A first end  14  of the valve body  12  may be fixed at the discharge port  152  of the non-orbiting scroll  150  of the compressor  100 A (e.g., by screw-thread connection or by pressing fit), and the first end of the valve body  12  is provided with a fluid inlet  15  aligned with the discharge port  152 . A side wall of the valve body  12  is provided therein with at least one fluid outlet  17  (in the embodiment shown in  FIGS. 6 and 7 , the number of the fluid outlets  17  is two) in fluid communication with the fluid inlet  15 , and a valve flap  20  for opening or closing the fluid outlet. In the embodiment shown in  FIGS. 6 and 7 , there may be two valve flaps  20 . However, it should be appreciated by the skilled person in the art that, the number of the valve flaps  20  may also be one or more. In particular, as shown in  FIG. 7 , an axis direction X2 of each fluid outlet  17  is inclined relative to an axis direction X1 of the fluid inlet  15 . In other words, the axis direction X1 of the fluid inlet  15  is not perpendicular to a plane X3 in which the valve flap  20  is located when the valve flap  20  closes the fluid outlet  17 . 
         [0062]    Compared with the discharge valve  170  as shown in  FIGS. 2 to 4  in which the axes of the fluid inlet and the fluid outlet (they may be considered as consisting of an upper part and a lower part of the valve port  175  in the valve seat  172  respectively) are overlapped with or parallel to each other (in other words, the axis direction of the fluid inlet is perpendicular to the plane in which the valve flap  174  is located), the discharge valve  10 A according to an embodiment of the present application has the axis direction X2 of the fluid outlet  17  inclined with respect to the axis direction X1 of the fluid inlet  15  (in other words, the axis direction X1 of the fluid inlet  15  is not perpendicular to the plane X3 in which the valve flap  20  is located when the valve flap  20  closes the fluid outlet  17 ). Therefore, in the process that the fluid enters into the valve body  12  through the fluid inlet  15  and then is discharged out of the valve body  12  through the fluid outlet  17  via the valve flap  20 , the flowing direction of the fluid is not turned by a right angle (90 degrees). Thus, the flowing resistance of the discharge valve  10 A may be reduced, and therefore the pressure drop caused by the discharge valve may be reduced. 
         [0063]    In the preferred embodiment as shown in  FIGS. 6 and 7 , an angle α between the axis direction X2 of the fluid outlet  17  and the axis direction X1 of the fluid inlet  15  is set to be greater than or equal to 70 degrees and less than or equal to 80 degrees. Alternatively, an angle β between the plane X3 in which the valve flap  20  is located when the valve flap  20  closes the fluid outlet  17  and the axis direction X1 of the fluid inlet  15  is set to be greater than or equal to 10 degrees and less than or equal to 20 degrees. 
         [0064]    The discharge valve  10 A according to a first embodiment of the present application may further include a valve stop  22  for limiting a displacement of the valve flap  20 . The valve flap  20  and the valve stop  22  may be fixed to the valve body  12  via fasteners such as a bolt  24 . Furthermore, for facilitating the assembly and preventing the valve flap or the valve stop from rotating about the bolt  24 , a pin  26  may be further adopted to achieve further positioning. 
         [0065]    In particular, a point of the valve flap  20  fixed to the valve body  12  (e.g., the position of the bolt  24 ) may be arranged to locate between the fluid outlet  17  and the fluid inlet  15  in an axial direction of the valve body. In other words, the opening direction of the valve flap  20  is arranged in a direction which allows the flowing resistance of the fluid to be minimized. Such configuration can further reduce the flowing resistance in the discharge valve  10 A. Further, a point of the valve stop  22  fixed to the valve body  12  (e.g., the position of the bolt  24 ) may also be arranged to locate between the fluid outlet  17  and the fluid inlet  15  in an axial direction of the valve body. 
         [0066]    The inventor made a comparison test between the discharge valve as shown in  FIGS. 6 and 7  according to the present application, and the discharge valve as shown in  FIG. 2 . The result is shown in table 1. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 comparison test 
               
             
          
           
               
                   
                 operating 
                   
               
               
                   
                 condition (° F.) 
                   
               
             
          
           
               
                   
                 (intake 
                   
                 EER 
               
             
          
           
               
                 test 
                   
                 temperature/ 
                 cooling 
                 power 
                 cooling 
                   
               
               
                 sequence 
                 discharge 
                 discharge 
                 capacity per 
                 consumption 
                 capacity/power 
               
               
                 No. 
                 valve type 
                 temperature) 
                 unit time 
                 (watt) 
                 consumption 
                 difference 
               
               
                   
               
             
          
           
               
                 1 
                 the present 
                 45/130 
                 130191.3 
                 11388 
                 11.43 
                 4.08% 
               
               
                 2 
                 application 
                 45/100 
                 158108.96 
                 8268 
                 19.12 
                 7.01% 
               
               
                 3 
                 conventional 
                 45/130 
                 129305.53 
                 11774 
                 10.98 
               
               
                 4 
                 discharge 
                 45/100 
                 157024.84 
                 8787 
                 17.87 
                 taken this as 
               
               
                   
                 valve shown 
                   
                   
                   
                   
                 reference 
               
               
                   
                 in FIG. 2 
               
               
                 5 
                 the present 
                 45/130 
                 129790.58 
                 11381 
                 11.40 
                 3.84% 
               
               
                 6 
                 application 
                 45/100 
                 157837.52 
                 8279 
                 19.06 
                 6.69% 
               
               
                 7 
                 no discharge 
                 45/130 
                 129963.49 
                 11375 
                 11.43 
                 4.08% 
               
               
                 8 
                 valve 
                 45/100 
                 158072.41 
                 8195 
                 19.29 
                 7.94% 
               
               
                   
               
             
          
         
       
     
         [0067]    The inventor made four groups of tests to the discharge valve according to the present application under different operating conditions (reference may be made to the test sequence Nos. 1, 2, 5 and 6), and made two groups of tests to the conventional discharge valve as shown in  FIG. 2  under different operating conditions (reference may be made to the test sequence Nos. 3 and 4). EER (=cooling capacity of the compressor/power consumption of the compressor) is adopted to represent the operating efficiency of the compressor. The EER of a compressor provided with the discharge valve according to the present application and the EER of a compressor provided with none of any types of discharge valves are calculated by taking the EER of a compressor provided with the conventional discharge valve as shown in  FIG. 2  as a reference. The result shows that, in a circumstance that an intake temperature and a discharge temperature of the compressor are respectively at 45° F. and 130° F. the EER of the compressor adopting the discharge valve according to the present application is increased by 3.84% to 4.08%, and in a circumstance that the intake temperature and the discharge temperature of the compressor are respectively at 45° F. and 100° F., the EER of the compressor adopting the discharge valve according to the present application is increased by 6.69% to 7.01%. 
         [0068]    For verifying the reliability of the above test, the inventor further made two groups of tests to the compressor in which no discharge valve is provided (reference may be made to the test sequence Nos. 7 and 8). The testing result shows that, compared with a compressor with a conventional discharge valve, the EER of a compressor with no discharge valve is respectively increased by 4.08% and 7.94%. 
         [0069]    According to the above results, it is obvious that the operating efficiency of the compressor provided with the discharge valve according to the present application is significantly higher than that of the compressor provided with the conventional discharge valve, and is slightly lower than the operating efficiency of the compressor in which no discharge valve is provided. Considering that, in many circumstances, it is necessary to provide a discharge valve to prevent the fluid with high pressure from flowing backward, the effect brought by the discharge valve according to the present application is very significant compared with a conventional discharge valve, and goes beyond the anticipation of the skilled person in the art. 
         [0070]    Furthermore, as shown in  FIG. 5 , the scroll compressor  100 A according to an embodiment of the present application may be a compressor which has a variable capacity. Hence, the scroll compressor  100 A further includes a capacity modulation mechanism  180 . The capacity modulation mechanism  180  modulates the capacity of the compressor by adjusting an axial displacement of the non-orbiting scroll  150  (i.e., the axial distance between the non-orbiting scroll  150  and an orbiting scroll  160 ). 
         [0071]    Reference is also made to  FIGS. 6 and 7 . The valve body  12  of the discharge valve  10 A may constitute a portion of the capacity modulation mechanism  180 . The capacity modulation mechanism  180  further includes a capacity modulation cylinder block  182 , and the second end  16  of the valve body  12  of the discharge valve  10 A may include a piston  18  which is movable in the capacity modulation cylinder block  182 . The capacity modulation cylinder block  182  is in fluid communication with an external pressure source via a connecting pipe  184 . An electromagnetic valve may be provided in a pipeline of the connecting pipe  184  to control the pressure in the capacity modulation cylinder block  182 . 
         [0072]    In practical operation, when the capacity of the scroll compressor  100 A is required to be reduced, the electromagnetic valve in the pipeline of the connecting pipe  184  is controlled to reduce the pressure in the capacity modulation cylinder block  182 , and thus the piston  18  at the second end  16  of the discharge valve  10 A will move upwardly. Since the first end  14  of the discharge valve  10 A is fixedly connected to the discharge port  152  of the non-orbiting scroll  150 , the non-orbiting scroll  150  is lifted upwardly, so as to form clearances between a spiral blade  156  of the non-orbiting scroll  150  and a end plate  164  of the orbiting scroll  160  as well as between the spiral blade  166  of the orbiting scroll  160  and the end plate  154  of the non-orbiting scroll  150 . Then, a part of compressed fluid may be leaked to the low pressure side through the clearances, thus reducing the capacity of the compressor. In contrary, when it is required to increase the capacity of the scroll compressor  100 A, the electromagnetic valve in the pipeline of the connecting pipe  184  is controlled to increase the pressure in the capacity modulation cylinder block  182 . Thus, the piston  18  at the second end  16  of the discharge valve  10 A will move downwardly. Therefore, the non-orbiting scroll  150  will be pressed downwardly to close the clearances between the non-orbiting scroll  150  and the orbiting scroll  160 , thus increasing the capacity of the compressor. 
         [0073]      FIGS. 8A and 8B  are a front view and a bottom view of a discharge valve  10 B according to a second embodiment of the present application, respectively. Unlike the first embodiment of the present application, three fluid outlets  17  and three sets of valve flaps  20  and valve stops  22  are provided in the discharge valve  10 B according to the second embodiment of the present application. Furthermore, these fluid outlets  17  may be centrosymmetrically arranged at equal angular intervals about the axis direction of the fluid inlet  15 . In addition, these fluid outlets  17  may be arranged at the same height along the axis direction of the fluid inlet  15 . 
         [0074]      FIGS. 9A and 9B  are a front view and a bottom view of a discharge valve  10 C according to a third embodiment of the present application, respectively. Unlike the first embodiment of the present application, four fluid outlets  17  and four sets of valve flaps  20  and valve stops  22  are provided in the discharge valve  10 C according to the third embodiment of the present application. Furthermore, these fluid outlets  17  may be centrosymmetrically arranged at equal angular intervals about the axis direction of the fluid inlet  15 . In addition, these fluid outlets  17  may be arranged at the same height along the axis direction of the fluid inlet  15 . 
         [0075]      FIGS. 10A and 10B  are an exploded perspective view and an assembly perspective view of a discharge valve  10 D according to a fourth embodiment of the present application, respectively. Unlike the above first, second and third embodiments of the present application, the discharge valve  10 D according to the fourth embodiment of the present application is provided with no piston for capacity modulation, hence, has a simpler structure, and is applicable in a compressor which has a fixed capacity or a scroll compressor which achieves capacity adjustment by other methods. 
         [0076]      FIG. 11  shows a discharge valve  10 E according to a fifth embodiment of the present application. The configurations and relationships of the valve body  12 , the fluid inlet  15 , the fluid outlet  17 , the valve flap  20  and the like of the discharge valve  10 E as shown in  FIG. 11  are similar to those in the embodiment as shown in  FIGS. 10A and 10B , which are not repeated herein. It is to be noted particularly that the valve flap  20  shown in  FIG. 11  is in an opened state. However, unlike the fourth embodiment, the discharge valve  10 E further includes a sleeve  30  fitted with the valve body  12 , and the fluid outlet  17  is located inside the cavity of the sleeve  30 . The sleeve  30  may be fixedly connected to the valve body  12 , for example, by pressing fit, screw-thread connection or welding, etc. A side wall of the sleeve  30  may be formed therein with at least one opening  32 . One end of the sleeve  30  may be formed as the piston  18 . The discharge valve  10 E as shown in  FIG. 11  is also applicable in the scroll compressor having the capacity modulating function as shown in  FIG. 5 . More specifically, the sleeve  30  or the valve body  12  may be fixed at the discharge port  152  of the non-orbiting scroll  150 , and the piston  18  on the sleeve  30  may be fitted in the capacity modulation cylinder block  182 . Similarly, the scroll compressor adopting the discharge valve  10 E according to this embodiment may perform capacity modulation by the above described method. 
         [0077]    In the above preferred embodiment, an example in which the angle α is set to be greater than or equal to 70 degrees and less than or equal to 80 degrees (or the angle β is set to be greater than or equal to 10 degrees and less than or equal to 20 degrees) is given. However, it should be appreciated by the skilled person in the art that, the present application is not limited to this, the above angles α and β may be other values to achieve an effect slightly worse than that achieved by selecting the above preferred range but still better than the effect achieved by a conventional discharge valve. For example, the angle α between the axis direction X2 of the fluid outlet  17  and the axis direction X1 of the fluid inlet  15  may be greater than or equal to 30 degrees and less than or equal to 80 degrees. In other words, the angle β between the plane X3 in which the valve flap  20  is located when the valve flap  20  closes the fluid outlet  17  and the axis direction X of the fluid inlet  15  may be greater than or equal to 10 degrees and less than or equal to 60 degrees. 
         [0078]    Further, the angle α between the axis direction X2 of the fluid outlet  17  and the axis direction X1 of the fluid inlet  15  may be greater than 0 degree and less than or equal to 90 degrees. In other words, the angle β between the plane X3 in which the valve flap  20  is located when the valve flap  20  closes the fluid outlet  17  and the axis direction X1 of the fluid inlet  15  may be greater than or equal to 0 degree and less than 90 degrees. 
         [0079]    Though the fluid inlet and the fluid outlet in the embodiments described above with reference to the drawings are shown in a circular shape, it should be appreciated by the skilled person in the art that, the fluid inlet and the fluid outlet each may have any other shape other than the circular shape. 
         [0080]    Similar to the first embodiment, in the second, third, fourth and fifth embodiments as shown in  FIGS. 8A to 11 , the valve flap may be a single valve flap, but it may also be two or multiple overlapped valve flaps. Furthermore, similar to the second and third embodiments as shown in  FIGS. 8A to 9B , the fourth and firth embodiments as shown in  FIGS. 10A, 10B and 11  may also be modified as including multiple fluid outlets. 
         [0081]    Furthermore, the effect of the discharge valve according to the embodiments of the present application is described with reference to a scroll compressor, however, it should be appreciated by the skilled person in the art that, the discharge valve according to the present application may further be applied in other types of compressor, including but not limited to a piston compressor, a screw rod compressor, a centrifugal compressor, and a rotor compressor, so as to achieve the effect of reducing the pressure drop caused by the discharge valve, and increasing the operating efficiency of the compressor. Furthermore, it should be appreciated by the skilled person in the art that the discharge valve according to the present application may also be applied in other machines which requires to control the discharge of the fluid, such as a pump, etc. 
         [0082]    While various embodiments of the present application have been described in detail herein, it should be understood that the present application is not limited to the specific embodiments described in detail and illustrated herein, and those skilled in the art can make other variations and modifications without departing from the principle and scope of the application. These variations and modifications should be deemed to fall into the protective scope of the application. Furthermore, all the elements described herein can be replaced by other technically equivalent elements.