Abstract:
A compressor ( 2 ) characterized by being equipped with: a rotary shaft ( 12 ); multiple impellers attached to the rotary shaft; a main flow path that guides a fluid from the prior-stage impeller to the latter-stage impeller; a chamber ( 31 ) that forms a circle centered around the axial line and connects to the main flow path; a suction nozzle ( 32 ) that guides the fluid from the outer circumferential side toward the inner circumferential side in the chamber; multiple movable vanes provided in the main flow path at intervals in the circumferential direction of the axial line and capable of moving and thereby adjusting the flow volume of the fluid passing through the main flow path; and a drive mechanism ( 42 ) that is provided at one side in the circumferential direction of the suction nozzle ( 32 ) within the chamber ( 31 ), and that changes the angle of the multiple movable vanes. In addition, of the one side and the other side in the circumferential direction within the chamber ( 31 ), the suction nozzle ( 32 ) is inclined toward the other side so as to increase the flow volume of the fluid toward the other side.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a compressor and a turbo chiller which is provided with the compressor. 
         [0002]    This application claims the right of priority based on Japanese Patent Application No. 2012-288891 filed with the Japan Patent Office on Dec. 28, 2012, the contents of which are incorporated herein by reference. 
       BACKGROUND ART 
       [0003]    A turbo chiller is a large-capacity heat source device which is widely used in applications such as air conditioning of a large-scaled factory having a clean room, such as an electrical and electronic related factory, or district heating and cooling. As the turbo chiller, a turbo chiller unitized by disposing configuration devices such as a compressor, a condenser, and a vaporizer near each other and integrating the configuration devices is known (refer to, for example, PTL 1). 
         [0004]    As the turbo chiller, a type in which a two-stage centrifugal compressor is used as a compressor and an intercooler is joined to the downstream of a first compression stage is known. Specifically, a gas refrigerant cooled in the intercooler is introduced to the downstream of the first compression stage through an intermediate suction chamber which surrounds an inlet portion of a second impeller configuring a second compression stage, and a slit formed between the intermediate suction chamber and a suction flow path provided around the inlet portion of the second impeller. 
         [0005]    Further, in the turbo chiller having such a centrifugal compressor, in order to control an operating range of the chiller, movable vanes in which an angle is changed according to the operation conditions are respectively provided in impellers configuring the first compression stage and the second compression stage. The movable vane is driven by a driving device integrally provided in the centrifugal compressor. However, a portion (referred to as a drive mechanism) of the driving device is installed in the intermediate suction chamber. 
         [0006]    Usually, the drive mechanism which is installed in the intermediate suction chamber is installed at the position of 180° in a circumferential direction from a suction nozzle for introducing a gas refrigerant into the intermediate suction chamber, that is, the farthest position with respect to the suction nozzle, in order to reduce the distribution in a circumferential direction of a flow at the joining position between an outlet of the intermediate suction chamber and a main flow path. 
         [0007]    Further, PTL 2 discloses a centrifugal compressor having a shape which leads a large quantity of fluid to one side in a circumferential direction in order to make the centrifugal compressor compact, in a suction flow path for introducing the fluid into an impeller of the centrifugal compressor. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         
           
             [PTL 1] Japanese Unexamined Patent Application Publication No. 2002-327700 
             [PTL 2] Japanese Unexamined Patent Application Publication No. 8-165996 
           
         
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0010]    Incidentally, as shown in  FIGS. 6 and 7 , a unitized turbo chiller  101  of the related art is disposed compactly to some extent, because major devices are intensively disposed. The turbo chiller  101  of the related art has, as main components, a centrifugal compressor  2  which compresses a gas refrigerant, a condenser  3  which condenses and liquefies the gas refrigerant compressed in the centrifugal compressor  2 , an intercooler  4  (an economizer) which temporarily stores a liquid refrigerant condensed in the condenser  3  and performs intermediate cooling, and a vaporizer  5  which vaporizes the liquid refrigerant which is led from the intercooler  4 . 
         [0011]    The respective devices are connected by pipes. For example, a discharge pipe  7  for leading the refrigerant after compression to the condenser  3 , and a suction pipe  8  which sucks in the gas refrigerant from the vaporizer  5  are connected to the centrifugal compressor  2 . Further, the intercooler  4  and the centrifugal compressor  2  are connected by a gas refrigerant pipe for an intercooler  9  which leads the gas refrigerant from a gas phase section of the intercooler  4  to an intermediate stage of the centrifugal compressor  2 . The driving device  37  described above is integrally provided in the centrifugal compressor  2 . 
         [0012]    However, the turbo chiller  101  of the related art does not have a fully satisfactory layout when considering that a plurality of turbo chillers are adjacently disposed or staked at the time of storage or transportation. 
         [0013]    In order to realize the compacting of a device, it is conceivable to optimize the arrangement of a compressor by changing the position of, for example, the above-described drive mechanism, or the like. However, in this case, there is a possibility that the drive mechanism may make flow distribution in a circumferential direction in an intermediate suction chamber non-uniform. 
         [0014]    Further, in the centrifugal compressor described in PTL 2, a drive mechanism is not provided, and in addition, a fluid is guided to one side in the circumferential direction according to the circumstances of the shape of the suction flow path, and the uniformity of flow distribution after guidance is not taken into account. 
         [0015]    The present invention provides a compressor in which it is possible to make the overall layout compact, and a turbo chiller which is provided with the compressor. 
       Solution to Problem 
       [0016]    (1) According to a first aspect of the present invention, there is provided a compressor including: a rotary shaft which rotates around an axis line; a plurality of impellers mounted on the rotary shaft; a main flow path which guides a fluid from the impeller of a preceding stage to the impeller of a subsequent stage; a chamber which has a ring shape centered on the axis line and communicates with the main flow path; a suction nozzle which introduces the fluid into the chamber toward an inner periphery side from an outer periphery side; a plurality of movable vanes which are provided in the main flow path at intervals in a circumferential direction with respect to the axis line and are movable, thereby adjusting a flow rate of the fluid flowing through the main flow path; and a drive mechanism which is provided on one side in the circumferential direction of the suction nozzle in the chamber and changes angles of the plurality of movable vanes, wherein the suction nozzle is inclined toward the other side out of one side and the other side in the circumferential direction in the chamber such that the flow rate of the fluid to the other side increases. 
         [0017]    According to the above configuration, the drive mechanism is provided on one side in the circumferential direction of the suction nozzle, whereby the arrangement of the compressor is optimized, and thus it is possible to make the overall layout of a turbo chiller compact. Further, the suction nozzle is inclined, whereby a flow rate flowing to the side opposite to the drive mechanism increases, and thus flow distribution in the circumferential direction in the chamber becomes more uniform. 
         [0018]    (2) In the compressor according to the above (1), it is preferable that a guide blade which guides the fluid such that the flow rate of the fluid to the other side out of one side and the other side in the circumferential direction in the chamber increases is provided on an outlet side of the suction nozzle. 
         [0019]    According to the above configuration, the fluid is guided by the guide blade, whereby it is possible to further improve the uniformity of the flow distribution in the circumferential direction in the chamber. 
         [0020]    (3) In the compressor according to the above (2), it is preferable that the guide blade is formed such that a length thereof becomes longer toward the other side in the circumferential direction. 
         [0021]    According to the above configuration, the flow rate of the fluid further flows into the side opposite to the drive mechanism, and thus it is possible to improve the uniformity of the flow distribution in the circumferential direction in the chamber. 
         [0022]    (4) In the compressor according to any one of (1) to (3), it is preferable that a flow path guide formed so as to make a flow path of the chamber narrower as it goes toward the drive mechanism is provided in the chamber. 
         [0023]    According to the above configuration, since the fluid is guided to the vicinity of the drive mechanism by the flow path guide, it is possible to further improve the flow distribution in the circumferential direction in the chamber. 
         [0024]    (5) In the compressor according to any one of (1) to (4), it is preferable that the drive mechanism is provided at a position spaced apart by 90° in the circumferential direction with respect to the suction nozzle. 
         [0025]    (6) Further, according to a second aspect of the present invention, there is provided a turbo chiller including: the compressor according to any one of (1) to (5). 
       Advantageous Effects of Invention 
       [0026]    According to the compressor related to each of the above aspects of the present invention, the drive mechanism is provided on one side in the circumferential direction of the suction nozzle, whereby the arrangement of the compressor is optimized, and thus it is possible to make the overall layout of a turbo chiller compact. Further, the suction nozzle is inclined, whereby a flow rate flowing to the side opposite to the drive mechanism increases, and thus the flow distribution in the circumferential direction in the chamber becomes more uniform. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0027]      FIG. 1  is a front view showing the configuration of the periphery of a centrifugal compressor of a turbo chiller according to a first embodiment of the present invention. 
           [0028]      FIG. 2  is a cross-sectional view showing an internal structure of a centrifugal compressor according to the first embodiment of the present invention. 
           [0029]      FIG. 3  is a cross-sectional view showing a partial configuration of the centrifugal compressor shown in  FIG. 2 . 
           [0030]      FIG. 4  is a cross-sectional view taken along line A-A of  FIG. 3 . 
           [0031]      FIG. 5  is a cross-sectional view corresponding to  FIG. 3 , of a centrifugal compressor according to a second embodiment of the present invention. 
           [0032]      FIG. 6  is a side view of a turbo chiller of the related art. 
           [0033]      FIG. 7  is a front view of the turbo chiller of the related art. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
       [0034]    Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. A turbo chiller of this embodiment has, as main components, a centrifugal compressor, a condenser which condenses and liquefies a gas refrigerant compressed in the centrifugal compressor, an intercooler which temporarily stores a liquid refrigerant condensed in the condenser and performs intermediate cooling, and a vaporizer which vaporizes the liquid refrigerant which is led from the intercooler, basically similar to the turbo chiller of the related art. Then, configuration devices such as the compressor, the condenser, and the vaporizer are disposed near each other and integrated with each other, thereby being unitized. 
         [0035]    As shown in  FIG. 1 , a suction pipe  8  which sucks in a gas refrigerant from the vaporizer is connected to a centrifugal compressor  2  of the turbo chiller of this embodiment, and an intercooler  4  and the centrifugal compressor  2  are connected by a gas refrigerant pipe for an intercooler  9  which leads the gas refrigerant from a gas phase section of the intercooler to an intermediate stage of the centrifugal compressor  2 . The gas refrigerant which is supplied from the gas refrigerant pipe for an intercooler  9  is introduced into an intermediate suction chamber  31  of the centrifugal compressor  2  through a suction nozzle  32 . 
         [0036]    In addition, a condenser  3 , the intercooler  4 , and a vaporizer  5  shown in  FIG. 1  are schematically shown and the accurate arrangement thereof in the turbo chiller of this embodiment is not reflected. 
         [0037]    A driving device  37  which drives a second movable vane  36  (refer to  FIGS. 2 and 3 ), which will be described later, is integrally provided in the centrifugal compressor  2 . A drive mechanism  42  such as a bracket  41  (refer to  FIG. 4 ) and a drive shaft  39  (refer to  FIG. 4 ), of the driving device  37 , is installed in the intermediate suction chamber  31 . 
         [0038]    Then, in the turbo chiller of this embodiment, in order to make the overall layout of the chiller compact (in order to reduce an installation area), the drive mechanism  42  which is a portion of the driving device  37  is disposed at the position of 90° in a circumferential direction with respect to the suction nozzle  32 . 
         [0039]    As shown in  FIGS. 2 and 3 , the centrifugal compressor  2  has a casing  11  which forms an outline, a rotary shaft  12  rotatably supported in the casing  11 , a motor  13  which rotationally drives the rotary shaft  12 , and a first impeller  15  and a second impeller  16  disposed to be spaced apart from each other in an axis line direction at the rotary shaft  12 . 
         [0040]    The rotary shaft  12  is rotatably supported on the casing  11  through a pair of bearings  14 . The driving force of the motor  13  is transmitted to the rotary shaft  12  through a gear mechanism  17 , and the first impeller  15  and the second impeller  16  also rotate according to the rotation of the rotary shaft  12 . A suction port  19  is provided on one side in the axis line direction of the casing  11  and a discharge port  20  is provided on the other side in the axis line direction. Further, an internal space  21  which makes the suction port  19  and the discharge port  20  communicate with each other is formed in the casing  11 . 
         [0041]    The first impeller  15  and the second impeller  16  are disposed in the internal space  21 , and the first impeller configures a first compression stage and the second impeller  16  configures a second compression stage. The internal space  21  is provided with a return flow path  23  connected to a flow path outlet  22  of the first impeller  15 , and a suction flow path  24  which connects the return flow path  23  and the second impeller  16 . The suction flow path  24  is an annular passage provided around an inlet portion of the second impeller  16 . 
         [0042]    The return flow path  23  makes the gas refrigerant flow toward a flow path inlet on the inside in a radial direction of the second impeller  16  from the flow path outlet  22  on the outside in the radial direction of the first impeller  15 . The return flow path  23  has a diffuser portion  26 , a bend portion  27 , and a return portion  28 . The diffuser portion  26  guides the gas refrigerant compressed by the first impeller  15  and discharged radially outward from the flow path outlet  22  of the first impeller  15 , to the outside in the radial direction. The outside in the radial direction of the diffuser portion  26  communicates with the return portion  28  through the bend portion  27 . 
         [0043]    Further, the gas refrigerant compressed in the second impeller  16  is discharged from the discharge port  20  of the casing  11  to a discharge flow path  7  (refer to  FIG. 7 ) by way of a discharge passage  25  provided around the second impeller  16 . 
         [0044]    A return vane  29  is disposed radially over the entire circumstances on the downstream side of the bend portion  27 . 
         [0045]    Further, in the centrifugal compressor  2 , the intermediate suction chamber  31  which causes the gas refrigerant that is generated in the intercooler  4  to join a discharge flow of the first impeller  15  and be then supplied to the second impeller  16  is provided. The intermediate suction chamber  31  is formed as an annular space surrounding the inlet portion of the second impeller  16 . The gas refrigerant from the intercooler  4  is supplied to the intermediate suction chamber  31  through the suction nozzle  32 . The suction nozzle  32  is connected to the gas refrigerant pipe for an intercooler  9  (refer to  FIG. 1 ). 
         [0046]    In an inner peripheral portion of the intermediate suction chamber  31 , a slit  33  is provided over the entire circumference, and thus the inside of the intermediate suction chamber  31  and the suction flow path  24  of the second impeller  16  are connected. 
         [0047]    Further, a first movable vane  35  in which an angle can be changed according to the operation conditions is provided at an inlet of the first impeller  15  of the first compression stage in the suction port  19  of the centrifugal compressor  2 . In addition, the second movable vane  36  in which an angle can be changed according to the operation conditions is provided at an inlet of the second impeller  16  of the second compression stage in the suction flow path  24  of the return flow path  23 . 
         [0048]    As shown in  FIG. 4 , the driving device  37  for driving the second movable vane  36  is provided in the centrifugal compressor  2 . The driving device  37  has a drive motor  38  provided outside the casing  11 , the drive shaft  39  which moves over a predetermined range in a horizontal direction orthogonal to the axis line direction by the rotation of the drive motor  38 , a drive ring  40  which rotates over a predetermined angle according to the movement of the drive shaft  39 , and the bracket  41  which connects the drive ring  40  and the drive shaft  39 . The second movable vane  36  is connected to the drive ring  40  by a predetermined link mechanism. 
         [0049]    Hereinafter, an operation of the driving device  37  will be described. First, if the drive motor  38  is driven, the driving force of the drive motor  38  is transmitted to the drive shaft  39  through a predetermined gear. The drive shaft  39  moves in a longitudinal direction by the driving force, thereby operating the bracket  41 . 
         [0050]    Subsequently, the bracket  41  operates the drive ring  40 , whereby the drive ring  40  rotates in the circumferential direction. In this way, the angle of the second movable vane  36  connected to the drive ring  40  through a predetermined link mechanism is changed. 
         [0051]    The drive ring  40 , the bracket  41 , and a portion of the drive shaft  39  of the driving device  37  are disposed in the intermediate suction chamber  31 . The bracket  41  and a portion of the drive shaft  39  disposed in the intermediate suction chamber  31  are hereinafter referred to as the drive mechanism  42 . 
         [0052]    Further, a plurality of guide blades  43  are provided close to an opening of the suction nozzle  32  in the intermediate suction chamber  31 . The guide blade  43  is a plate-shaped guide provided so as to connect an inner wall on one side in the axis line direction of the intermediate suction chamber  31  and an inner wall on the other side in the axis line direction and has a shape diffusing the gas refrigerant which is introduced from the suction nozzle  32  to both sides in the circumferential direction of the intermediate suction chamber  31 . 
         [0053]    As described above, in the turbo chiller of this embodiment, in order to make the overall layout of the chiller compact (in order to reduce an installation area), the drive mechanism  42  which is a portion of the driving device  37  is disposed at the position of 90° in the circumferential direction with respect to the suction nozzle  32 . That is, the drive mechanism  42  is provided on one side in the circumferential direction of the suction nozzle  32  in the intermediate suction chamber  31 . 
         [0054]    Here, the suction nozzle  32  of the intermediate suction chamber  31  is inclined such that the flow rate of the gas refrigerant to the side opposite to the side on which the drive mechanism  42  is provided increases. That is, the suction nozzle  32  is formed such that the flow rate of the gas refrigerant to the other side in the circumferential direction in the intermediate suction chamber  31  increases. 
         [0055]    Specifically, a flow path area orthogonal to a gas introduction direction G of the suction nozzle  32  is formed such that the side opposite to the drive mechanism  42  is larger. 
         [0056]    Further, also with regard to the guide blades  43 , the guide blades  43  are formed such that the flow rate of the gas refrigerant becomes larger on the other side in the circumferential direction, that is, such that the length of the guide blade  43  on the side opposite to the drive mechanism  42  becomes longer. 
         [0057]    Specifically, the plurality of guide blades  43  are formed so as to become longer as the distance from the drive mechanism  42  increases. For example, a guide blade  43   s  most distant from the drive mechanism  42  is made longer than (for example, double) a guide blade  43   b  closest to the drive mechanism  42 . 
         [0058]    Further, the plurality of guide blades  43  are disposed such that the distance between the guide blades  43  adjacent to each other becomes wider as the distance from the drive mechanism  42  increases. For example, a distance C 1  between downstream-side end portions of the guide blade  43   a  which is at the position most distant from the drive mechanism  42  and the guide blade  43  disposed next to the guide blade  43   a  is disposed so as to be wider than a distance C 2  between the guide blade  43   b  closest to the drive mechanism and the guide blade disposed next to the guide blade  43   b.    
         [0059]    Next, an operation of the turbo chiller of this embodiment will be described. 
         [0060]    In the turbo chiller of this embodiment, the vaporizer  5 , the centrifugal compressor  2 , the condenser  3 , and the intercooler  4  are connected by the pipes, thereby configuring a closed system which circulates a refrigerant. The gas refrigerant introduced from the gas phase section of the intercooler  4  of these devices is introduced into the intermediate suction chamber  31  of the centrifugal compressor  2  by the suction nozzle  32 . 
         [0061]    The gas refrigerant having flowed into the intermediate suction chamber  31  flows into a suction passage of the second impeller  16  through the slit  33  and is sucked into the second impeller  16  along with refrigerant vapor discharged from the first impeller  15 . 
         [0062]    Further, the intercooler  4  and the centrifugal compressor  2  are connected by the gas refrigerant pipe for an intercooler  9  which leads the gas refrigerant from the gas phase section of the intercooler  4  to the intermediate stage of the centrifugal compressor  2 . 
         [0063]    According to the above-described embodiment, the arrangement of the centrifugal compressor  2  is optimized by providing the drive mechanism  42  at the position spaced apart by 90° in the circumferential direction on one side in the circumferential direction of the suction nozzle  32 , and thus it is possible to make the overall layout of the turbo chiller compact. 
         [0064]    Further, the suction nozzle  32  is inclined, whereby the flow rate flowing to the side opposite to the drive mechanism  42  increases, and thus the flow distribution in the circumferential direction in the intermediate suction chamber  31  becomes more uniform. 
         [0065]    Further, the length of the guide blade  43  is formed so as to become longer as the distance from the drive mechanism  42  increases, and the distance between the guide blades  43  is disposed so as to become wider as the distance from the drive mechanism  42  increases, whereby the gas refrigerant further flows into the side opposite to the drive mechanism  42 , and thus the uniformity of the flow distribution in the circumferential direction in the intermediate suction chamber  31  is improved. 
         [0066]    In this way, a bias in the circumferential direction of the flow in the outlet of the intermediate suction chamber  31  is suppressed, and therefore, it is possible to suppress a decrease in the performance of the second impeller  16  which is located downstream. 
       Second Embodiment 
       [0067]    Next, a turbo chiller according to a second embodiment of the present invention will be described. In addition, in this embodiment, description is made focusing on the differences from the first embodiment described above and description of the same portions is omitted. 
         [0068]    As shown in  FIG. 5 , the centrifugal compressor  2  of the turbo chiller of this embodiment is characterized in that a flow path guide  44  making a flow path width become narrower as it approaches the drive mechanism  42  is provided in the intermediate suction chamber  31 . 
         [0069]    The flow path guide  44  is a plate-shaped guide provided so as to connect the inner wall on one side in the axis line direction of the intermediate suction chamber  31  and the inner wall on the other side in the axis line direction, similar to the guide blade  43 . Specifically, the flow path guide  44  is a guide having a curved shape narrowing a flow path width further toward the drive mechanism  42  side than the suction nozzle  32  at the position spaced apart by 180° in the circumferential direction with respect to the suction nozzle  32  (on the side opposite to the suction nozzle  32 ). 
         [0070]    According to the above-described embodiment, the flow path area in the circumferential direction of the inside of the intermediate suction chamber  31  is gradually narrowed by the flow path guide  44 , whereby the gas refrigerant is led to the vicinity of the drive mechanism with increased velocity. In this way, the flow distribution in the circumferential direction in the intermediate suction chamber  31  is improved. 
         [0071]    In addition, the technical scope of the present invention is not limited to each of the embodiments described above and includes forms in which various changes are applied to the above-described embodiments within a scope which does not depart from the gist of the present invention. That is, the configurations and the like mentioned in the above-described embodiments are an example, and changes can be appropriately made. 
         [0072]    For example, in this embodiment, a configuration in which the suction nozzle  32  and the drive mechanism  42  are spaced apart from each other by 90° in the circumferential direction is shown. However, there is no limitation thereto, and a configuration of making the entire device more compact by further narrowing the distance is also acceptable. 
       INDUSTRIAL APPLICABILITY 
       [0073]    The above-described compressor and turbo chiller are suitable for a turbo chiller unitized by disposing configuration devices such as a compressor, a condenser, and a vaporizer near each other and integrating the configuration devices. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1 : turbo chiller 
           2 : centrifugal compressor 
           3 : condenser 
           4 : intercooler 
           5 : vaporizer 
           12 : rotary shaft 
           15 : first impeller 
           16 : second impeller 
           21 : internal space 
           23 : return flow path 
           31 : intermediate suction chamber (chamber) 
           32 : suction nozzle 
           33 : slit 
           36 : second movable vane 
           37 : driving device 
           39 : drive shaft 
           40 : drive ring 
           41 : bracket 
           42 : drive mechanism 
           43 : guide blade 
           44 : flow path guide