JP2008095678A - Centrifugal compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a device while ensuring smooth movement of a diffuser wall. <P>SOLUTION: During operation of the centrifugal compressor, a movable diffuser wall 17 is disposed in an initial set position in Fig. 1 to perform general fluid compressing action. At a low flow rate of the centrifugal compressor, an actuator 28 is operated to rotate the movable diffuser wall 17 clockwise by an angle shown in Fig. 5. According to this, the contact position of a movable cam 25 is changed, and the wall 17 is moved in parallel toward a fixed diffuser wall 11 by distortion of an annular flexible member 18 provided on the inner circumferential side thereof. Since the flexible member 18 fulfills seal function, the diffuser wall 17 can be smoothly and rapidly moved with a minimized driving force without providing a seal on a sliding surface laid along the moving direction of the diffuser wall 17. The movement of the wall 17 controls the passage of a diffuser 10 to be matched with a flow rate supplied from an impeller 4, so that the diffuser effect can be sufficiently ensured even at a low flow rate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a centrifugal compressor in which a diffuser wall that forms a diffuser disposed on the outer periphery of an impeller is configured to be movable.

  In a centrifugal compressor, a technique is known in which the diffuser wall is moved according to the flow rate and the passage width of the diffuser is controlled to an appropriate state so that the diffuser effect is sufficiently obtained over a wide range from low flow rate to high flow rate. is there.

  For example, Patent Document 1 discloses a centrifugal compressor having the following configuration. That is, the diffuser ring 37 having one wall portion 34a of the parallel wall diffuser 34 is arranged so as to form a concentric circle around the second stage impeller 17b, and is sealed on the casing 25 (denoted by the reference numerals in the drawing). Not supported). The diffuser ring 37 is rotatable in the circumferential direction and movable in the axial direction of the second stage impeller 17b, and a groove 37a is formed on the outer peripheral surface thereof obliquely with respect to the axial direction of the second stage impeller 17b. . A protrusion 40 provided on the casing 25 is fitted into the groove 37 a of the diffuser ring 37. On the other hand, a shaft body 38 driven in the length direction by the drive unit 39 is pivotally supported by the diffuser ring 37. Accordingly, when the shaft body 38 is driven in the length direction by the drive unit 39, the diffuser ring 37 rotates on the support surface of the casing 25 in the circumferential direction because the oblique groove 37 a is fitted in the protrusion 40. While moving, it slides in the axial direction of the second stage impeller 17b, and the passage width of the parallel wall diffuser 34 is reduced.

Patent Document 2 discloses a centrifugal compressor having the following configuration. That is, of the pair of wall portions 27 and 28 that define the diffuser portion 26, the moving wall portion 29 is supported on the support surface 27 a of one wall portion 27 via the three balls 31. The moving wall portion 29 can be moved in the axial direction of the impeller 21 via the rod 33a by an actuator 33 that is electrically operated. Further, a sealing member 32 made of an elastic body is interposed between the facing surface 27 b of the wall portion 27 and the back surface 29 a of the moving wall portion 29, so that the air accelerated by the impeller 21 does not short pass to the scroll portion 30. . The seal member 32 can be expanded and contracted in the moving direction of the moving wall portion 29. Accordingly, by interposing the ball 31 between the moving wall portion 29 and the support surface 27a as described above and providing the seal member 32 other than the support surface 27a, friction during movement of the moving wall portion 29 is eliminated. Explains that the movement can be smoothed.
JP 2002-48098 A JP-A-4-47199

  However, as represented by Patent Document 1, in the configuration in which the diffuser ring 37 slides on the support surface of the casing 25, the air accelerated by the second stage impeller 17b does not leak from the sliding portion of the diffuser ring 37. Thus, it is necessary to provide a seal on the sliding surface. For this reason, there exists a problem that a big sliding resistance arises and the diffuser ring 37 cannot move smoothly. In order to solve such a problem, it is necessary to increase the driving force of the diffuser ring 37, but this causes a new problem that the driving mechanism must be enlarged.

  In the invention disclosed in Patent Document 2, a moving wall portion 29 is arranged between a pair of wall portions 27 and 28 that define the diffuser portion 26 in order to eliminate sliding resistance, and the seal member 32 is a moving wall portion. The structure provided in the gap between the wall portion 27 and the moving wall portion 29 without being provided in the sliding portion 29 is employed. However, this gap must be made extremely narrow so that the centrifugal compressor does not become large. For this reason, the method of attaching the seal member 32 to both the wall portion 27 and the moving wall portion 29 can only depend on the adhesion means, but the adhesion work in a narrow gap is not easy, and the assembly work of the seal member 32 is extremely difficult. There is a problem that there is, and practical application is difficult. Further, if the gap is increased so that the assembly work of the seal member 32 is facilitated, the apparatus itself is increased in size.

  An object of the present invention is to enable smooth movement of the diffuser wall and to reduce the size of the apparatus.

According to the first aspect of the present invention, an impeller is fixed to a rotating shaft supported by a casing, a diffuser is disposed around the impeller, and at least one of a pair of diffuser walls disposed with the diffuser interposed therebetween. In the centrifugal compressor configured to be movable in the longitudinal direction of the rotary shaft as a movable diffuser wall that can approach and separate from the other diffuser wall,
The movable diffuser wall is attached to a support body, which is disposed on the inner peripheral side of the movable diffuser wall and cannot move in the longitudinal direction of the rotating shaft, via an annular flexible member.

  According to the present invention described in claim 1, since the annular flexible member provided on the inner peripheral side of the movable diffuser wall performs a sealing function, it is necessary to provide a seal on the sliding surface along the moving direction of the movable diffuser. Thus, the movable diffuser wall can be moved quickly even with a small driving force. Moreover, a drive part can be reduced in size by reducing required drive force, the structure around the said diffuser is simplified, and the enlargement of a centrifugal compressor can be suppressed. Furthermore, the annular flexible member interposed between the support and the movable diffuser wall does not cause the difficulty of assembly as in the prior art seal member, and it is not necessary to increase the gap on the back surface of the impeller. The enlargement of the centrifugal compressor can be suppressed.

  The invention of claim 2 is characterized in that the flexible member is formed of a diaphragm, so that the structure of connecting the one diffuser wall to the support can be simplified.

  The invention according to claim 3 is characterized in that the support body is constituted by a support plate rotatably attached to the casing via a bearing with a sealing function, and therefore the rotating shaft of the movable diffuser wall The movement in the longitudinal direction can be configured using the rotation of the movable diffuser wall itself, and the configuration of the drive unit can be simplified.

  According to a fourth aspect of the present invention, in the configuration in which the movable diffuser wall is moved in the longitudinal direction of the rotation shaft, a plurality of sloped movable cams provided on the back surface of the movable diffuser wall, and the movable on the casing. A plurality of inclined fixed cams provided so as to come into contact with the cam and an actuator for driving the movable diffuser wall in the rotational direction; The diffuser wall can be moved, and the configuration of the drive unit can be simplified.

  The present invention according to claim 5 is characterized in that the support is constituted by a part of the casing, so that the component is more than when the support is constituted by a support plate provided rotatably. The score can be reduced.

  In the invention of claim 6, the configuration in which the movable diffuser wall is moved in the longitudinal direction of the rotating shaft has a plurality of sloped driven cams provided on the back surface of the movable diffuser wall, and the casing is rotatable. And a plurality of sloped drive cams that contact the driven cam provided on the rotary plate, and an actuator that drives the rotary plate in the rotational direction. Since the diffuser wall can be configured to move only in the longitudinal direction of the rotating shaft, and the movable diffuser wall does not need to have a rotation function, the movable diffuser wall moves with respect to a change in the amount of fluid supplied by the impeller. Improve the following ability. Moreover, since all the components for moving the movable diffuser wall are provided on the casing side, the entire design and assembly are facilitated.

  In the present invention, the movement of the diffuser wall can be made smooth with a simple configuration, and the passage width of the diffuser can be reliably controlled.

(First embodiment)
Hereinafter, the first embodiment will be described with reference to FIGS.
The casing of the centrifugal compressor of the present invention is configured by joining the first casing 1 and the second casing 2 in the first embodiment. A rotating shaft 5 to which an impeller 4 is fixed is rotatably supported by a casing wall 3 extending in the radial direction of the first casing 1 via a bearing 6 with a sealing function.

  The second casing 2 includes a parallel flow path 8 and a suction port 9 that expands in a funnel shape in front of the funnel-shaped space 7 that houses the impeller 4 (left side in FIG. 1). A diffuser 10 is disposed on the outer periphery of the impeller 4. A fixed diffuser wall 11 forming a passage of the diffuser 10 is formed by a part of the second casing 2, and a volute 12 is formed between the rear surface and the inner peripheral wall of the second casing 2. The volute 12 is continuous with a discharge port (not shown). Accordingly, the fluid sucked from the suction port 9 by the rotation of the impeller 4 is compressed and supplied to the diffuser 10 side arranged on the outer periphery in the radial direction by the centrifugal force of the impeller 4.

  On the other hand, in the first casing 1, an annular inner peripheral space 13 and an outer peripheral space 14 wider in the longitudinal direction of the rotary shaft 5 than the inner peripheral space 13 are formed behind the impeller 4 (right side in FIG. 1). ing. An annular support plate 15 is arranged in the inner circumferential space 13, and the support plate 15 is supported by the casing wall 3 through a bearing 16 with a sealing function so as to be rotatable and immovable in the longitudinal direction of the rotary shaft 5. Yes.

  An annular movable diffuser wall 17 is disposed in the outer peripheral space 14 so as to face the fixed diffuser wall 11 with the diffuser 10 interposed therebetween. The movable diffuser wall 17 is supported by the support plate 15 via an annular flexible member 18 having an inner peripheral surface made of a diaphragm.

  Specifically, as shown in FIG. 3, the flexible member 18 is formed in a donut shape with a center passing therethrough, and has a predetermined rigidity in the radial direction but deforms in a direction perpendicular to the radial direction. Made of possible flexible material. The flexible member 18 has an inner peripheral edge 18 a disposed in an annular mounting groove 19 formed in the support plate 15 and an outer peripheral edge 18 b disposed in an annular mounting groove 20 formed in the movable diffuser wall 17. An annular fixing plate 21, 22 is fitted into each mounting groove 19, 20 and fixed by screws 23, 24, and the support plate 15, the flexible member 18 and the movable diffuser wall 17 are integrated. . Therefore, the movable diffuser wall 17 can be rotated in the circumferential direction together with the support plate 15 and the flexible member 18, and can be moved and displaced in the longitudinal direction of the rotary shaft 5 by the flexible member 18.

  As shown in FIGS. 2 and 6, the movable diffuser wall 17 has a movable cam 25 having four inclined surfaces fixed to the back surface thereof. The movable cam 25 is formed in an arc shape so as to be concentric with the movable diffuser wall 17, and its cam surface is formed as an inclined surface that decreases in the clockwise direction (upward direction in FIG. 6) as viewed in FIG. 2.

  On the casing wall 3 side of the first casing 1, four inclined fixed cams 26 formed in an arc shape are disposed at positions corresponding to the movable cams 25. The cam surface of the fixed cam 26 is formed as an inclined surface that becomes lower in the counterclockwise direction (downward in FIG. 6) as viewed in FIG. Further, the movable cam 25 and the fixed cam 26 are disposed at a position where they are always in contact. In the present embodiment, the movable cam 25 is pressed toward the fixed cam 26 by the fluid pressure of the diffuser 10, but the contact state may be maintained using a spring or the like, for example.

  A connecting pin 27 is further provided on the back surface of the movable diffuser wall 17. The length of the connecting pin 27 is formed longer than the distance that the movable diffuser wall 17 moves in the longitudinal direction of the rotating shaft 5. The connecting pin 27 is connected to a connecting member 30 connected to an operating member 29 of an actuator 28 attached to the first casing so as to be rotatable and slidable in the longitudinal direction of the connecting pin 27. Accordingly, when the actuator 28 is operated and the operating member 29 is pulled in the left direction in FIG. 2, the movable diffuser wall 17 is rotated by a predetermined amount in the clockwise direction in FIG. 2 via the connecting member 30 and the connecting pin 27.

  The actuator 28 in the present embodiment is not shown in detail, but is formed by a fluid cylinder. The actuator 28 is connected to the discharge port side of the volute 12 (not shown) to supply the fluid supplied from the impeller 4. The fluid cylinder is configured to operate with characteristics such that the flow rate on the discharge side and the protruding amount of the actuating member 29 are inversely proportional to the change in flow rate on the discharge port side in accordance with the change. However, in the present invention, no matter what kind of actuator 28 is used, there is no problem. For example, an actuator using a solenoid or the like can be electrically operated at a predetermined low flow rate. .

The operation of the first embodiment configured as described above will be described below.
During normal operation of the centrifugal compressor, the flow rate is relatively large and the actuator 28 is in an inoperative state, so the connecting pin 27 is in the position of FIG. For this reason, the movable cam 25 and the fixed cam 26 are in contact with each other as shown in FIG. 6A, and the movable diffuser wall 17 is disposed at the initial setting position shown in FIG.

  When the centrifugal compressor is started up or decelerated, the operating member 29 is immersed and the connecting member 30 pulls the connecting pin 27 to the left in FIG. 2, so that the movable diffuser wall 17 has an angle θ as shown in FIG. Is only turned clockwise. As the movable diffuser wall 17 rotates, the movable cam 25 moves on the slope of the fixed cam 26 from the phantom line position to the solid line position as shown in FIG. 6B, so that the movable diffuser wall 17 moves from the phantom line position to the solid line position. Move by distance L.

  That is, as shown in FIG. 4, the movable diffuser wall 17 translates toward the fixed diffuser wall 11 side by the bending of the flexible member 18. Since the movable diffuser wall 17 has no sliding portion in the direction of moving toward the fixed diffuser wall 11, it can be moved smoothly and quickly even with a small driving force. The movement of the movable diffuser wall 17 reduces the passage width of the diffuser 10. As a result, the diffuser 10 is controlled to have a passage width corresponding to the flow rate supplied from the impeller 4, and a sufficient diffuser effect can be obtained even at low flow rates. Therefore, an efficient fluid compression action can be performed. The amount of movement of the movable diffuser wall 17 by the actuator 28 is variously adjusted according to the amount of fluid supplied by the impeller 4.

The above-described first embodiment of the present invention has the following effects.
(1) Since the movable diffuser wall 17 is supported by the flexible member 18, the annular flexible member 18 provided on the inner peripheral side of the movable diffuser wall 17 performs a sealing function, and the movable diffuser wall 17 There is no need to provide a seal on the sliding surface along the moving direction, and even a small driving force can be reliably moved, and the passage width of the diffuser 10 can be quickly controlled. Further, the annular flexible member 18 interposed between the support plate 15 and the movable diffuser wall 17 is assembled to the support plate 15 and the movable diffuser wall 17 with a relatively large mounting area by the fixed plates 21 and 22. Therefore, there is no difficulty in assembling unlike the conventional sealing member.
(2) Since the flexible member 18 that supports the movable diffuser wall 17 is supported by the support plate 15 attached to the casing wall 3 of the first casing 1 via the bearing 16 with a sealing function, the movable diffuser wall 17 During the rotation, sliding resistance is not received between the support plate 15 and the support plate 15.
(3) Since the movable diffuser wall 17, the flexible member 18, and the support plate 15 form an integrated annular body, the diffuser 10 can be hermetically sealed and immediately after being supplied from the impeller 4 to the diffuser 10. The high-pressure fluid leaking into the inner peripheral space 13 and the outer peripheral space 14 or leaking from the gap between the outer peripheral surface of the movable diffuser wall 17 and the inner peripheral surface of the first casing 1 circulates between the diffuser 10. Therefore, the pressure increasing function in the diffuser 10 can be performed as set.
(4) Since the movable diffuser wall 17 is only supported by the flexible member 18, the number of parts can be reduced and the configuration around the diffuser 10 can be simplified, contributing to the downsizing of the centrifugal compressor. be able to.
(5) Since the movable diffuser wall 17 is moved in the longitudinal direction of the rotary shaft 5 by using the rotation of the movable diffuser wall 17 and the inclined movable cam 25 and fixed cam 26, the drive mechanism can be simplified. Therefore, it can contribute to the downsizing of the centrifugal compressor.

(Second Embodiment)
The second embodiment shown in FIGS. 7 to 10 is a modification of the configuration in which the movable diffuser wall 17 in the first embodiment is moved in the longitudinal direction of the rotary shaft 5, and the configuration of other centrifugal compressors is the first. This is the same as the first embodiment. Accordingly, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, an annular space 31 is formed at a position corresponding to the diffuser 10 in the casing wall 3 of the first casing 1 constituting the casing of the present invention. A movable diffuser wall 17 is disposed in the annular space 31 so as to face the fixed diffuser wall 11. The movable diffuser wall 17 is attached to the casing wall 3 via an annular flexible member 32 and to the outer peripheral wall of the first casing 1 via an annular flexible member 32a. Specifically, the inner peripheral edge of the flexible member 32 is sandwiched by an annular mounting groove 33 formed in the casing wall 3 by the same annular fixing plate 34 and fixed by a screw (not shown), and the outer peripheral edge is a movable diffuser. It is clamped by an annular fixing plate 36 in an annular mounting groove 35 formed in the wall 17 and fixed by a screw (not shown). The flexible member 32 a has an inner peripheral edge sandwiched between the mounting groove 35 and the fixing plate 36, and an outer peripheral edge at the joint between the outer peripheral wall of the first casing 1 and the outer peripheral wall of the second casing 2. It is pinched. The flexible member 32 and the flexible member 32a are made of a flexible material that has a predetermined rigidity in the radial direction and can be deformed in a direction perpendicular to the radial direction. Therefore, the movable diffuser wall 17 is supported by the first casing 1 in a state in which the movable diffuser wall 17 is movable in the longitudinal direction of the rotary shaft 5 through the flexible member 32 and the flexible member 32a. Further, the presence of the flexible member 32 and the flexible member 32 a blocks the flow of fluid between the diffuser 10 and the annular space 31.

  A driven cam 37 is fixed to the back surface of the movable diffuser wall 17. As shown in FIG. 8, the driven cam 37 is formed in an arc shape and is arranged at four locations. Further, as shown in FIG. 10, the cam surface of the driven cam 37 is formed as an inclined surface that rises upward (counterclockwise in FIG. 8).

  On the other hand, in the annular space 31, an annular rotating plate 38 is rotatably attached to the casing wall 3 via a bearing 39 with a sealing function so as to face the back surface of the movable diffuser wall 17. The rotating plate 38 is disposed with a slight gap between the back surface (right side in FIG. 7) and the side surface of the casing wall 3 to prevent the occurrence of rotational resistance due to close contact. An arcuate drive cam 40 is fixed to the front surface of the rotating plate 38 (left side in FIG. 7) at a position facing each driven cam 37 of the movable diffuser wall 17. Contrary to the driven cam 37, the cam surface of the drive cam 40 is composed of an inclined surface that becomes lower in the upward direction in FIG. 10 (counterclockwise in FIG. 8). The driven cam 37 is always in contact with the drive cam 40 because the movable diffuser wall 17 receives the fluid pressure in the diffuser 10.

  A connecting pin 41 is fixed to a part of the rotating plate 38 so as to protrude into the annular space 31. As shown in FIG. 8, the connecting pin 41 is rotatably connected to the tip of a connecting member 44 that is actuated by an actuator 42. Therefore, when the actuator 42 is actuated, the actuating member 43 and the connecting member 44 project rightward in FIG. 8, and the rotating plate 38 is rotated counterclockwise via the connecting pin 41.

The operation of the second embodiment configured as described above will be described below.
During normal operation of the centrifugal compressor, the flow rate is relatively large and the actuator 42 is in an inoperative state, so the connecting pin 41 is in the position of FIG. For this reason, the driven cam 37 and the drive cam 40 are in contact with each other in FIG. 10A, and the movable diffuser wall 17 is disposed at the initial setting position in FIG. 7, and a normal fluid compression action is performed.

  When the flow rate is low, such as when the centrifugal compressor is started up or decelerated, the operating member 43 protrudes due to the operation of the actuator 42. Therefore, the connecting member 44 pushes the connecting pin 41 to the right in FIG. Rotated in the direction. As the rotating plate 38 rotates, the drive cam 40 moves on the inclined surface of the driven cam 37 from the phantom line position to the solid line position as shown in FIG. 10B, so that the movable diffuser wall 17 moves from the phantom line position to the solid line position. Move by distance L.

  That is, as shown in FIG. 9, the movable diffuser wall 17 translates toward the fixed diffuser wall 11 side by the bending of the flexible member 32. The movable diffuser wall 17 has no sliding portion in the direction of moving toward the fixed diffuser wall 11 and is only displaced in the longitudinal direction of the rotary shaft 5, so that even a small driving force is stable. It is moved smoothly and quickly in the state. The movement of the movable diffuser wall 17 reduces the passage width of the diffuser 10. As a result, the diffuser 10 is controlled to have a passage width commensurate with the flow rate supplied from the impeller 4, and a diffuser effect can be sufficiently obtained even at a low flow rate. A good fluid compression action can be performed. The amount of movement of the movable diffuser wall 17 by the actuator 42 is variously adjusted according to the amount of fluid supplied by the impeller 4.

The above-described second embodiment of the present invention has the following effects.
(1) Since the movable diffuser wall 17 is moved only in the longitudinal direction of the rotating shaft, the followability of the movement of the movable diffuser wall 17 with respect to the change in the fluid supply amount by the impeller 4 is good.
(2) A configuration for rotating the movable diffuser wall 17 is not required, and the number of components can be reduced as compared with the first embodiment.
(3) Since all the configurations for moving the movable diffuser wall 17 in the longitudinal direction of the rotary shaft 5 can be provided on the casing side, the entire design and assembly are facilitated, and the centrifugal compressor is reduced in size. be able to.

  The present invention is not limited to the configurations of the first and second embodiments, and various modifications are possible within the scope of the spirit of the present invention, and can be implemented as follows.

(1) The flexible member 18 is not limited to the one configured by the diaphragm as in the first embodiment, and may be any annular thin plate that can be bent in the longitudinal direction of the rotary shaft 5, and the material thereof. It is not specifically limited to.
(2) The pair of movable cams 25 and fixed cams 26 or drive cams 40 and driven cams 37 can be disposed at a plurality of positions of at least three.
(3) The drive means for moving the movable diffuser wall 17 is not limited to the combination of the movable cam 25 or the drive cam 40 and the fixed cam 26 or the driven cam 37, and for example, spirals on one of the movable diffuser wall 17 and the first casing 1. It can be set as the structure which forms a groove | channel and provides the pin fitted to a spiral groove in the other.
(4) The driving means for moving the movable diffuser wall 17 can be configured to move in the longitudinal direction of the rotary shaft 5 by directly pushing the movable diffuser wall 17 with an actuator without using a cam. In this embodiment, the flexible member 18 that supports the movable diffuser wall 17 can be directly attached to the first casing 1 as in the second embodiment, and the support plate 15 in the first embodiment is not necessary. The number of parts can be reduced, which can contribute to the downsizing of the centrifugal compressor.
(5) The movable diffuser wall 17 and the moving mechanism of the movable diffuser wall 17 can be implemented by replacing the position of the fixed diffuser wall 11 with each other. In this embodiment, the member forming the volute 12 needs to be provided separately from the movable diffuser wall.
(6) The present invention can also be implemented in a centrifugal compressor in which a plurality of fluid compression mechanisms including the impeller 4, the diffuser 10, and the volute 12 are provided in the longitudinal direction of the rotary shaft 5.
(7) Both the fixed diffuser wall 11 and the movable diffuser wall 17 arranged with the diffuser 10 interposed therebetween may be configured to be movable in the longitudinal direction of the rotary shaft 5.

It is sectional drawing of the centrifugal compressor which shows 1st Embodiment. It is the sectional view on the AA line of FIG. It is an enlarged view which shows the principal part of 1st Embodiment. It is sectional drawing which shows the operating state of the centrifugal compressor corresponding to FIG. It is the BB sectional view taken on the line of FIG. (A) It is operation | movement explanatory drawing at the time of the normal driving | operation of 1st Embodiment. (B) It is operation | movement explanatory drawing at the time of the low flow volume of 1st Embodiment. It is sectional drawing of the centrifugal compressor which shows 2nd Embodiment. It is CC sectional view taken on the line of FIG. It is the elements on larger scale which show the operation state of the centrifugal compressor corresponding to FIG. (A) It is operation | movement explanatory drawing at the time of the normal driving | operation of 2nd Embodiment. (B) It is operation | movement explanatory drawing at the time of the low flow volume of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st casing 2 2nd casing 4 Impeller 5 Rotating shaft 9 Intake port 10 Diffuser 11 Fixed diffuser wall 12 Volute 15 Rotating support plate 17 Movable diffuser walls 18, 32, 32a Flexible members 21, 22, 34, 36 Fixed plate 25 Movable cam 26 Fixed cam 27 Connecting pin 28, 42 Actuator 37 Driven cam 40 Drive cam

Claims (6)

A movable diffuser in which an impeller is fixed to a rotating shaft supported by a casing, a diffuser is disposed around the impeller, and at least one of a pair of diffuser walls disposed with the diffuser interposed therebetween can approach and separate from the other diffuser wall. In the centrifugal compressor configured to be movable in the longitudinal direction of the rotating shaft as a wall,
The centrifugal compressor is characterized in that the movable diffuser wall is attached to a support body, which is disposed on the inner peripheral side of the movable diffuser wall and cannot move in the longitudinal direction of the rotating shaft, via an annular flexible member.   The centrifugal compressor according to claim 1, wherein the flexible member is formed of a diaphragm.   The centrifugal compressor according to claim 1 or 2, wherein the support is configured by a support plate rotatably attached to the casing via a bearing with a sealing function.   The movable diffuser wall is configured to move in the longitudinal direction of the rotation shaft. The centrifugal compressor according to claim 3, comprising a slope-shaped fixed cam and an actuator that drives the movable diffuser wall in a rotational direction.   The centrifugal compressor according to claim 1, wherein the support is configured by a part of the casing.   The configuration in which the movable diffuser wall is moved in the longitudinal direction of the rotating shaft includes a plurality of sloped driven cams provided on the back surface of the movable diffuser wall, a rotating plate rotatably provided on the casing, and the rotating plate. 6. The driving device according to claim 1, further comprising: a plurality of slant-shaped driving cams that contact the driven cam provided on the actuator, and an actuator that drives the rotating plate in a rotating direction. The centrifugal compressor according to item 1.

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