JP2018168759A - Geared Compressor - Google Patents

Abstract

To provide a geared compressor that can realize stable operation by avoiding contact between blades of an impeller and a casing.SOLUTION: A geared compressor 1 according to the present invention comprises a rotatable impeller 20 fixed to a rotating shaft, and a casing 12 including a housing space housing the impeller 20. The casing 12 comprises a plurality of split rings 50 constituting a part of an inner peripheral surface surrounding the housing space of the casing 12, each being movable forward and backward in a radial direction of the casing 12, and provided in a circumferential direction of the casing 12.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a geared compressor capable of realizing stable operation.

In plants such as petrochemical, chemical, and air separation, centrifugal compressors are used as rotating machines. Centrifugal compressors are structurally divided into two types.
One is a single-shaft multi-stage compressor. A rotor is configured by attaching a plurality of impellers (impellers) for compressing gas to a single rotor shaft. Both ends of the rotor shaft are supported by a pair of bearings. Is done. In the case of a single-shaft multistage compressor, when the rotational speed of the drive source is lower than the rotational speed of the compressor, a speed increaser is provided between the drive source and the rotor shaft. Another type is a compressor with a built-in speed increasing mechanism (Integrally Geared Compressor).

  Generally, in a geared compressor, a pair of impellers are accommodated in a casing without contact with the casing, and a rotor shaft provided with a pair of impellers at both ends is rotatably supported. The power of the drive shaft that is rotationally driven by the drive source is transmitted to the rotor shaft via the speed increasing gear mechanism.

  In recent years, various improvements have been made on such geared compressors. For example, Patent Document 1 describes a geared compressor that improves the performance of an impeller.

JP 2010-048188 A

Incidentally, the geared compressor of Patent Document 1 includes an open impeller in which impeller blades are exposed as they are. The open impeller is also accommodated in the casing in a non-contact state, but during operation, the blade of the open impeller may be deformed to expand radially outward due to the centrifugal force, and the blade and the casing may come into contact with each other. There is.
For this reason, in order to realize a more stable operation, even if an open impeller is used, it is necessary to avoid contact between the blade of the impeller and the casing.

  In view of the above, an object of the present invention is to provide a geared compressor capable of avoiding contact between impeller blades and a casing and realizing stable operation.

A geared compressor of the present invention includes a rotatable impeller fixed to a rotating shaft, and a casing having a housing space for housing the impeller.
The casing has a plurality of split rings that are provided along the circumferential direction of the casing, each of which constitutes a part of the inner peripheral surface surrounding the housing space of the casing and that can move forward and backward in the radial direction of the casing. It is characterized by.

  The casing in the geared compressor of the present invention includes a plurality of split ring storage chambers that open into the storage space and each store a plurality of split rings, and each split ring is in the radial direction of the split ring in the split ring storage chamber. It is preferable to move forward and backward in the radial direction in accordance with the pressure in the back pressure applying space provided outside the front.

In the geared compressor of the present invention, the pressure in the back pressure application space is preferably adjusted by introducing gas compressed through the accommodation space and discharging gas from the back pressure application space to the outside. .
Further, the pressure in the back pressure applying space is higher than the pressure in the accommodation space when the dividing ring is moved from the radially outer side to the inside, and the accommodating space is moved when the dividing ring is moved from the radially inner side to the outside. The pressure is preferably lower than

  In the geared compressor of the present invention, it is preferable that a movement restricting mechanism for restricting a radial movement range of the divided ring is provided between the divided ring and the casing.

  The split ring in the geared compressor of the present invention moves back and forth between the radially innermost reduced diameter position and the radially outermost enlarged diameter position, and the inner peripheral surface of the casing at the reduced diameter position. It is preferable to be flush with each other.

  In the geared compressor of the present invention, the pressure adjustment in the back pressure application space is performed based on one or both of the detection result of the interval between the casing and the impeller in the radial direction and the detection result of the pressure in the back pressure application space. Are preferred.

  The split ring in the geared compressor of the present invention is preferably provided on the upstream side in the gas flow direction in the accommodation space.

  According to the present invention, it is possible to avoid contact by adjusting the interval between the casing and the impeller during operation of the geared compressor by providing a split ring that advances and retracts in a radial direction in a part of the casing.

It is explanatory drawing which shows schematic structure of the geared compressor which concerns on embodiment of this invention. It is sectional drawing of the 1st centrifugal compression part which concerns on this embodiment. (A) is a top view of the abutting surface of the outlet flow path formation body of the 1st centrifugal compression part which concerns on this embodiment, (b) is a top view of the abutting surface of an inlet flow path formation body. (A) is a top view of the division | segmentation ring of the 1st centrifugal compression part which concerns on this embodiment, (b) is the bb sectional view taken on the line of (a). (A) is a figure which shows the state of a split ring when a geared compressor is stationary, (b) is a figure which shows the state of a split ring when a geared compressor is drive | operating. (A) is a figure which shows the state of a split ring when a geared compressor is stationary, (b) is a figure which shows the state of a split ring when a geared compressor is drive | operating. It is a graph which shows the fluctuation | variation of the space | interval of the casing and impeller during operation | movement of a geared compressor.

Hereinafter, embodiments of the present invention will be described.
The geared compressor 1 includes the tip edge 27 of the blade 23 and the inner peripheral surface 13 of the casing 12 when the first centrifugal compressor 10 is in an operation state, particularly in an unsteady state from the start of operation to a steady state. An interval adjusting mechanism for adjusting the interval B is provided.
As shown in FIGS. 6A and 6B, the interval adjusting mechanism is configured such that the split ring 50 accommodated in the split ring accommodating chamber 60 moves forward and backward between the reduced diameter position X and the enlarged diameter position Y. The interval B is adjusted.

[Geared compressor 1]
As shown in FIG. 1, the geared compressor 1 according to the present embodiment includes a pair of first centrifugal compression units provided at both ends of a main shaft 2 and a driven shaft 4 to which the rotational driving force of the main shaft 2 is transmitted. 10, a second centrifugal compression unit 80 provided on the driven shaft 7, and a discharge port of the second centrifugal compression unit 80. A third centrifugal compressor 90 provided on the driven shaft 7, having a suction port connected to the outlet and the pipe 82.

  The geared compressor 1 has a speed increasing gear mechanism that increases the speed of rotation of the driven shafts 4 and 7. Specifically, as shown in FIG. 1, a main drive gear 3 that is rotationally driven integrally with the main drive shaft 2, a follower gear 5 provided on the follower shaft 4, and a follower gear provided on the follower shaft 7. 8, meshing with the driving gear 3 and the driven gear 5, meshing with the transmission gear 6 that transmits the rotation of the driving gear 3 by the driven gear 5, and the driving gear 3 and the driven gear 8, and rotating the driving gear 3 with the driven gear 8. A transmission gear 9 for transmission.

  As shown in FIG. 1, the geared compressor 1 sucks the gas G from the outside in the pair of first centrifugal compression units 10 and boosts the pressure. Then, the gas pressurized by the first centrifugal compression unit 10 is further pressurized by the second centrifugal compression unit 80, and the gas pressurized by the second centrifugal compression unit 80 is further pressurized by the third centrifugal compression unit 90. The pressurized gas is discharged toward a portion that consumes the gas G through a pipe 92 connected to the discharge port of the third centrifugal compression unit 90.

Hereinafter, the first centrifugal compression unit 10 will be described.
In the present embodiment, the direction orthogonal to the direction of the rotation axis C of the driven shaft 4 is referred to as the radial direction, the side close to the radial rotation axis C is the inner side in the radial direction, and the side far from the radial rotation axis C. Is called the outside in the radial direction.
In addition, the upstream side α and the downstream side β are defined with reference to the direction in which the gas flows.
In the present embodiment, the inner side, the outer side, the upstream side α, and the downstream side β in the radial direction indicate a relative positional relationship.

[First centrifugal compression unit 10]
As shown in FIG. 2, the first centrifugal compression unit 10 includes an impeller 20 that is coaxially fixed to the driven shaft 4 and a casing 12 that rotatably accommodates the impeller 20.
The first centrifugal compression unit 10 compresses the gas supplied from the inlet channel 31 formed in the casing 12 and discharges the compressed gas from the outlet channel 41.

[Impeller 20]
As shown in FIG. 2, the impeller 20 includes a disk 21 fixed to the driven shaft 4 and a plurality of blades 23 provided on the surface of the disk 21 with a predetermined interval in the circumferential direction.
The diameter of the disk 21 gradually decreases from the proximal end side fixed to the driven shaft 4 toward the distal end along the rotation axis C.

As shown in FIG. 2, the blade 23 extends from the surface of the disk 21 toward the inner peripheral surface 13 of the casing 12. The blade 23 is opposed to the inner peripheral surface 13 with a tip edge 27 having a predetermined distance B.
The blade 23 is radially outward from between the inlet edge 24 into which the gas G flows between the blades 23, 23 adjacent to the distal end side of the disk 21 and the blades 23, 23 adjacent to the proximal end side of the disk 21. And an outlet edge 25 from which the gas G flows out.

[Case 12]
As shown in FIG. 2, the casing 12 includes an inlet channel forming body 30 that forms the inlet channel 31, an outlet channel forming body 40 that forms the outlet channel 41, and the inlet channel forming body 30 and the outlet flow. A split ring 50 disposed between the path forming bodies 40.
In the casing 12, the inlet flow path forming body 30 is disposed on the upstream side α, and the outlet flow path forming body 40 is disposed on the downstream side β with respect to the inlet flow path forming body 30. Are connected in a state in which the inlet channel 31 and the outlet channel 41 are connected.
The split ring 50 is accommodated in a split ring storage chamber 60 formed by combining the inlet flow path forming body 30 and the outlet flow path forming body 40 so as to be movable forward and backward.

[Inlet channel forming body 30]
As shown in FIG. 2, the inlet channel forming body 30 has an inlet channel 31 for allowing gas to flow into the first centrifugal compression unit 10 from the upstream side α, and an annular butt formed at the end of the downstream side β. As shown in FIGS. 6A and 6B, the surface 32 and a first locking ridge 35 projecting vertically from the abutting surface 32 toward the downstream side β are provided.

As shown in FIG. 3B, the first locking ridges 35 are formed in an arc shape, and four are formed concentrically around the rotation axis C.
As shown in FIGS. 6A and 6B, the first locking protrusion 35 is inserted into the locking groove 59 of the split ring 50 and restricts the movement range of the split ring 50.

[Exit channel forming body 40]
As shown in FIG. 2, the outlet flow path forming body 40 is connected to the abutting surface 42 formed at the end of the upstream side α in contact with the inlet flow path forming body 30 and the inlet flow path 31, so that the gas flows out to the outside. And an outlet scroll 41 in which the outlet channel 41 is formed.
As shown in FIG. 3, the outlet channel forming body 40 includes a storage chamber 43 that stores the split ring 50 from the abutting surface 42, an air supply pipe 47 and an outflow pipe 49 that are connected to the storage chamber 43, and an outlet channel 41. And a distance sensor 46 disposed in the space.
As shown in FIG. 2, the outlet flow path forming body 40 includes a space that accommodates most of the impeller 20 therein. The outlet channel 41 is connected to a space that accommodates the impeller 20.

As shown in FIG. 3A, the storage chamber 43 is recessed by a predetermined distance from the abutting surface 42 provided on the outer peripheral side, and has a uniform depth toward the inner peripheral surface 13.
In the present embodiment, four storage chambers 43 are provided, and as shown in FIG. 3A, adjacent storage chambers 43, 43 are partitioned by four partitions 44 provided at equal intervals in the circumferential direction.
Each partition 44 is provided with a partition main body 44A standing from the bottom of the storage chamber 43 and extending in the radial direction, and arms 44B protruding from both sides in the circumferential direction of the partition main body 44A. In the partition 44, the partition main body 44A and the arm 44B are formed at the same height.

The storage chamber 43 has four second locking protrusions 45 inside.
As shown in FIG. 3A, the second locking protrusion 45 connects the arms 44 </ b> B and 44 </ b> B of the adjacent partitions 44 and 44.
The second locking protrusion 45 is erected substantially vertically from the bottom surface of the storage chamber 43 and has an arcuate planar shape.
The second locking protrusion 45 has a dimension (thickness) from the bottom surface of the accommodation chamber 43 that is substantially equal to the first locking protrusion 35 and is thinner than the partition 44.
The second locking protrusion 45 is inserted into the locking groove 59 of the split ring 50.

[Air pipe 47]
The air supply pipe 47 is used to increase the pressure of the space A by sending the gas G into the space A of the split ring housing chamber 60 described later. The space A is formed on the outer side in the radial direction from the split ring 50 when the split ring 50 is stored in the split ring storage chamber 60.
One end of the air supply pipe 47 is connected to the storage chamber 43, and the other end is connected to the outlet channel 41, and the compressed gas G passing through the storage space and flowing through the outlet channel 41 is supplied to the interior of the split ring storage chamber 60. Can be introduced.
As shown in FIG. 3A, the opening of the air supply pipe 47 on the side of the storage chamber 43 is formed so as not to be blocked by the split ring 50 stored in the split ring storage chamber 60.

The air supply pipe 47 has a first control valve V1. The first control valve V1 controls the inflow of the compressed gas G into the space A.
An example of the first control valve V1 is an electromagnetic valve whose flow path is opened and closed according to a command. The same applies to the second control valve V2. The opening and closing of the first control valve V1 is controlled by a control device (not shown).

[Outflow pipe 49]
The outflow pipe 49 is for causing the gas G to flow out from the space A of the split ring housing chamber 60 to the external space and reducing the pressure in the space A.
The outflow pipe 49 connects the external space of the first centrifugal compression unit 10 and the storage chamber 43.
The opening on the storage chamber 43 side of the outflow pipe 49 is formed so as not to be blocked by the split ring 50 stored in the split ring storage chamber 60 as shown in FIG.

  The outflow pipe 49 has a second control valve V2. The second control valve V2 is opened when the gas G in the space A flows out to the external space.

[Interval sensor 46]
The interval sensor 46 detects the interval B between the tip edge 27 of the blade 23 and the inner peripheral surface 13 of the casing 12.
As shown in FIG. 3A, the distance sensor 46 is provided on the inner peripheral surface 13 of the casing 12, and a capacitance sensor that detects a capacitance between the inner peripheral surface 13 and the tip edge 27 can be applied. . The interval sensor 46 can detect the interval B between the inner peripheral surface 13 and the end edge 27 by detecting a change in capacitance according to the change in the interval between the end edge 27 and the end edge 27.

[Split ring storage chamber 60]
The split ring storage chamber 60 stores the split ring 50.
As shown in FIG. 1 and FIGS. 6A and 6B, the split ring housing chamber 60 is formed at a boundary portion between the inlet channel forming body 30 and the outlet channel forming body 40. As shown in FIGS. 6 (a) and 6 (b), the accommodation chamber 43 constitutes the split ring accommodation chamber 60 when the abutting surface 32 and the abutting surface 42 are in contact with each other. Corresponding to the four storage chambers 43, the four split ring storage chambers 60 are arranged in an annular shape in the circumferential direction of the casing 12.
The opening of the split ring housing chamber 60 is provided so as to correspond to the tip edge 27 on the upstream side α of the blade 23.

As shown in FIGS. 6A and 6B, the split ring housing chamber 60 includes a movement restricting guide 61 including a first locking protrusion 35 and a second locking protrusion 45 therein. . The movement restriction guide 61 is formed with a movement restriction guide 61 for restricting the movement of the split ring 50 in the radial direction. The movement restriction guide 61 has an annular shape.
The split ring storage chamber 60 is sized in the radial direction so that when the split ring 50 is stored, a space A is formed on the outer side in the radial direction from the split ring 50.

[Split ring 50]
The split ring 50 adjusts the distance B between the tip edge 27 of the blade 23 and the inner peripheral surface 13 of the casing 12.
As shown in FIG. 4A, the split ring 50 includes four split rings 50A, a split ring 50B, a split ring 50C, and a split ring 50D. The split rings 50 </ b> A to 50 </ b> D have an arcuate planar shape and are arranged in an annular shape by being housed in the corresponding split ring housing chamber 60.
When there is no need to distinguish the split rings 50A to 50D, they are simply referred to as split rings 50.

As shown in FIG. 4B, the split ring 50 has an H-shaped cross section, a web 51 extending in the radial direction, a first flange 53 protruding from one end in the radial direction of the web 51, and the web 51. And a second flange 57 projecting from the other end in the radial direction. A space between the first flange 53 and the second flange 57 forms a locking groove 59.
While the first flange 53 is moving between the reduced diameter position X and the expanded diameter position Y, a labyrinth seal structure is formed by the split ring 50, the locking groove 59, and the movement restriction guide 61 of the split ring housing chamber 60. To do.

As shown in FIGS. 4A and 4B, the first flange 53 projects from the web 51 in the direction of the rotation axis C and projects from the circumferential end of the web 51.
As shown in FIG. 5B, the first flange 53 abuts against the arm 44 </ b> B of the partition 44, thereby restricting the movement of the split ring 50 outward in the radial direction. Further, as shown in FIG. 6B, the first flange 53 abuts against the first locking ridge 35 and the second locking ridge 45, that is, the movement restricting guide 61, so that the radial direction of the split ring 50 is reached. The movement of the outside of the. At this time, the split ring 50 is in a diameter expansion position Y located on the outermost side in the radial direction of the moving range.

The inner peripheral surface 55 of the first flange 53 is exposed from the opening of the split ring housing chamber 60 toward the inside of the casing 12 as shown in FIG.
The inner peripheral surface 55 of the first flange 53 is flush with the inner peripheral surface 13 of the casing 12 when the split ring 50 is disposed at the reduced diameter position X located on the innermost side in the radial direction of the moving range. It is formed as follows. Thus, the inner peripheral surface 55 of the first flange 53 serves as a part of the inner peripheral surface 13 of the casing 12.

As shown in FIGS. 4A and 4B, the second flange 57 projects from the web 51 in the same manner as the first flange 53.
As shown in FIG. 5A, the second flange 57 abuts against the arm 44 </ b> B of the partition 44 to restrict the movement of the split ring 50 inward in the radial direction. Further, as shown in FIG. 6A, the second flange 57 abuts against the first locking protrusion 35 and the second locking protrusion 45, thereby moving the split ring 50 inward in the radial direction. regulate. At this time, the split ring 50 is in the reduced diameter position X.

The locking groove 59 is locked with the movement restriction guide 61 inserted therein, thereby restricting the movement of the split ring 50 in the radial direction.
As shown in FIG. 4B, the locking groove 59 is formed between the first flange 53 and the second flange 57 that protrude from the web 51. Accordingly, the locking groove 59 is formed in the split ring 50 over the entire region in the circumferential direction.
The locking groove 59 has a radial dimension larger than the thickness of the movement restricting guide 61 so that the movement restricting guide 61 can move relatively in the radial direction inside the engaging groove 59. For this reason, a gap H is formed between the locking groove 59 and the movement restricting guide 61 in the radial direction as shown in FIGS. The gap H is equal to the moving distance of the split ring 50 from the reduced diameter position X to the expanded diameter position Y.
By providing the gap H, the split ring 50 can move back and forth between the reduced diameter position X and the enlarged diameter position Y inside the split ring storage chamber 60.

  The width of the split ring 50 in the direction of the rotation axis C is equal to or slightly smaller than the width of the storage chamber 43 in the direction of the rotation axis C. Thereby, even if the split ring 50 is accommodated in the accommodation chamber 43, the abutting surface 32 of the inlet channel forming body 30 and the abutting surface 42 of the outlet channel forming body 40 can be brought into contact with each other.

  Next, with reference to FIG. 7, regarding the change in the interval B between the inner peripheral surface 13 and the tip edge 27, the first centrifugal compressor 10 starts operation until the rotational speed of the driven shaft 4 becomes constant. The unsteady state I and the steady state II in which the rotational speed of the driven shaft 4 is constant will be described separately.

First, the change in the interval B in the unsteady state I will be described.
When the first centrifugal compression unit 10 starts operation, the impeller 20 is deformed so as to extend outward in the radial direction by the centrifugal force generated by the rotation of the driven shaft 4. The deformation of the impeller 20 increases as the rotational speed of the driven shaft 4 increases as shown in FIG.
Moreover, since the temperature of the compressed gas G becomes high, the inner peripheral surface 13 of the casing 12 is displaced outward in the radial direction due to thermal expansion.
However, in the unsteady state I, since the temperature of the gas G cannot be increased, the amount of deformation of the impeller 20 is larger than the amount of displacement of the casing 12. Therefore, in the unsteady state I, the interval B between the inner peripheral surface 13 and the tip edge 27 is gradually reduced as the rotational speed of the driven shaft 4 increases.

On the other hand, in the steady state II, since the rotational speed of the driven shaft 4 is constant, the deformation of the impeller 20 outward in the radial direction is within a certain range as shown in FIG. On the other hand, since the temperature of the gas G becomes higher in the casing 12, the casing 12 is further thermally expanded with the passage of time, and the inner peripheral surface 13 is further displaced outward in the radial direction.
For this reason, in the steady state II, the deformation amount of the casing 12 becomes larger than the deformation amount of the impeller 20 with time, so that the interval B between the inner peripheral surface 13 and the tip edge 27 gradually increases. However, since the temperature of the gas G also reaches the upper limit, the interval B converges to a certain range.

[Operation of interval adjustment mechanism]
The geared compressor 1 includes an interval adjusting mechanism to cope with the change in the interval B in the unsteady state I and the steady state II. Hereinafter, the operation of the interval adjusting mechanism during operation of the geared compressor 1 will be described. This operation is realized by controlling the opening and closing of the first control valve V1 and the second control valve V2 based on the interval B detected by the interval sensor 46 during operation of the geared compressor 1.

  The first centrifugal compressor 10 has a threshold value P1 and a threshold value P2 set for the interval B in order to control opening and closing of the first control valve V1 and the second control valve V2. As shown in FIG. 7, the threshold value P2 is larger than the threshold value P1.

When the 1st centrifugal compression part 10 has stopped, the 1st control valve V1 and the 2nd control valve V2 shall be closed.
When the first centrifugal compressor 10 starts operation, the first control valve V1 is opened, and the compressed gas G is caused to flow from the outlet channel 41 into the space A that is the back pressure application space. At this time, the second control valve V2 is closed. Thereby, the split ring 50 is arranged at the reduced diameter position X. During the operation stop, among the split rings 50 </ b> A to 50 </ b> D, there are the split ring 50 at the reduced diameter position X and the split ring 50 at the expanded diameter position Y.

  And in the unsteady state I, when the space | interval B detected by the space | interval sensor 46 becomes narrow and reaches the threshold value P1, while the 1st control valve V1 will close, the 2nd control valve V2 will open. Thereby, a part of the gas G in the space A flows out to the external space through the outflow pipe 49, and the pressure of the gas G in the space A becomes equal to the atmospheric pressure. For this reason, since the pressure of the gas G in the space A is lower than the pressure of the gas G in the housing space near the first flange 53, the split ring 50 expands from the reduced diameter position X as shown in FIG. Moving to the radial position Y, the interval B increases.

Thereafter, the operation of the first centrifugal compressor 10 shifts from the unsteady state I to the steady state II.
In the steady state II, as shown in FIG. 7, when the interval B detected by the interval sensor 46 spreads and reaches the threshold value P2 with time, the first control valve V1 opens and the second control valve V2 is reached. Closes. As a result, the gas G compressed from the air supply pipe 47 flows into the space A and pushes the split ring 50, so that the split ring 50 moves to the reduced diameter position X and the interval B becomes narrow.

[Effect of first centrifugal compression unit 10]
Next, the effect which the 1st centrifugal compression part 10 has is demonstrated.
In the first centrifugal compression unit 10, a movement restricting mechanism for restricting the radial movement range of the split ring 50 is configured by the locking groove 59 in the split ring 50 and the movement restricting guide 61 of the split ring accommodating chamber 60. .
And the 1st centrifugal compression part 10 moves between the diameter reduction position X and the diameter expansion position Y by the space | interval adjustment mechanism based on the comparison result of the space | interval B detected and threshold value P1, P2. .
Thereby, when the detected interval B is narrowed to the threshold value P1, it is possible to prevent the casing 12 and the blade 23 of the impeller 20 from contacting each other by moving the split ring 50 to the enlarged diameter position Y and expanding the interval B. .

  Further, when the interval B increases to the threshold value P2 as the first centrifugal compression unit 10 is operated, the split ring 50 is moved from the enlarged diameter position Y to the reduced diameter position X, and the distance B between the casing 12 and the blade 23 of the impeller 20 is increased. Narrowing can improve the efficiency of compression.

Further, a movement restriction guide 61 is inserted into the locking groove 59 of the split ring 50 housed in the split ring housing chamber 60.
When the first flange 53 is disposed at the reduced diameter position X, as shown in FIG. 5A, the second flange 57 and the movement restriction guide 61 come into contact with each other, so that the gas in the inlet channel 31 is in the space A. Can be prevented from leaking.
Further, when the first flange 53 is disposed at the diameter-enlarged position Y, as shown in FIG. 5B, the first flange 53 abuts against the movement restriction guide 61, so that the gas in the inlet channel 31 flows. Leakage into the space A can be suppressed.

  The preferred embodiment of the present invention has been described above, but the configuration described in the above embodiment is selected or changed to another configuration as long as it does not depart from the gist of the present invention. be able to.

  For example, in this embodiment, a flow control valve can be used as the first control valve V1 and the second control valve V2 instead of the on-off valve.

  In the present embodiment, the distance sensor 46 is used to detect the distance B between the leading edge 27 of the blade 23 and the inner peripheral surface 13 of the casing 12, but the first sensor is used together with the distance sensor 46 or instead of the distance sensor 46. A pressure sensor that detects the pressure of the gas G in the housing space near the flange 53 may be used.

  Further, in addition to the pressure sensor that detects the pressure of the gas G in the accommodation space near the first flange 53, a sensor that detects the pressure of the gas inside the adjusted space A may be provided. Thereby, based on the detection result of the sensor which detects the pressure of the gas inside the adjusted space A and the sensor which detects the pressure of the gas flowing near the inlet edge 24 of the blade 23, the gas inside the space A The pressure can be adjusted stepwise, and the first flange 53 can be arranged not only at the reduced diameter position X and the expanded diameter position Y but also at a predetermined position between the reduced diameter position X and the expanded diameter position Y. it can.

  Moreover, although the example of what is called an open impeller showed the impeller 20 of the 1st centrifugal compression part 10, this invention is applicable also to a closed impeller.

  In the present embodiment, the annular movement restricting guide 61 is formed in the split ring accommodating chamber 60. However, the movement restricting guide 61 includes the first engaging protrusion 35 and the second engaging protrusion 45, or the divided ring accommodation. It may be formed by only a pair of arms 44B and 44B facing each other in the chamber 60. In this case, the locking groove 59 is not formed over the entire area in the circumferential direction of the split ring 50, but only on the surface facing the movement restriction guide 61 of the split ring 50 housed in the split ring housing chamber 60. Is formed.

  Further, in the present embodiment, when the operation of the first centrifugal compression unit 10 is started, the split ring 50 is arranged at the reduced diameter position X, but when the operation starts the operation of the first centrifugal compression unit 10, the inside of the space A The first flange 53 of the split rings 50 </ b> A to 50 </ b> D may be disposed at the diameter expansion position Y.

  The geared compressor 1 includes a pair of the first centrifugal compression unit 10, the second centrifugal compression unit 80, the third centrifugal compression unit 90, and four centrifugal compression units. There is no limit to the number. Furthermore, in the present embodiment, the interval adjustment mechanism is provided only in the first centrifugal compression unit 10, but the interval adjustment mechanism may be provided also in the second centrifugal compression unit 80 and the third centrifugal compression unit 90.

DESCRIPTION OF SYMBOLS 1 Geared compressor 2 Drive shaft 3 Drive gear 4 Drive shaft 5 Drive gear 6 Transmission gear 7 Drive shaft 8 Drive gear 9 Transmission gear 10 1st centrifugal compression part 12 Casing 13 Inner peripheral surface 14 Piping 20 Impeller 21 Disk 23 Blade 24 Inlet Edge 25 Exit edge 27 Tip edge 30 Inlet channel forming body 31 Inlet channel 32 Abutting surface 35 First locking protrusion 40 Outlet channel forming body 41 Outlet channel 42 Abutting surface 43 Accommodating chamber 44A Partition body 44B Arm 45 First Two locking ridges 46 Interval sensor 47 Air supply pipe 48 Discharge scroll 49 Outflow pipe 50 Split ring 51 Web 53 First flange 55 Inner peripheral surface 57 Second flange 59 Locking groove 60 Split ring storage chamber 61 Movement restriction guide 80 Second Centrifugal compression section 82 piping 90 Third centrifugal compression section 92 piping

Claims (8)

A rotatable impeller fixed to the rotating shaft;
A casing having a housing space for housing the impeller, and
The casing is
A plurality of split rings provided along the circumferential direction of the casing, each of which constitutes a part of an inner peripheral surface surrounding the accommodation space of the casing and is movable forward and backward in the radial direction of the casing;
A geared compressor characterized by that. The casing is
A plurality of split ring storage chambers that open into the storage space and each store the plurality of split rings,
Each of the split rings moves forward and backward in the radial direction according to the pressure of a back pressure applying space provided outside the split ring in the radial direction of the split ring in the chamber.
The geared compressor according to claim 1. The pressure in the back pressure application space is:
It is adjusted by introducing gas compressed through the accommodation space and discharging the gas from the back pressure application space to the outside.
The geared compressor according to claim 2. The pressure in the back pressure application space is:
When moving the split ring from the outside in the radial direction to the inside, higher than the pressure of the accommodation space,
When the split ring is moved from the inner side to the outer side in the radial direction, the pressure in the accommodating space is lower than
The geared compressor according to any one of claims 2 to 3. Between the split ring and the casing,
A movement restricting mechanism for restricting the radial movement range of the split ring is provided;
The geared compressor according to any one of claims 1 to 4. The split ring is
Advancing and retreating between the radially innermost reduced diameter position and the radially outermost diameter expanded position;
In the reduced diameter position, the casing becomes flush with the inner peripheral surface of the casing.
The geared compressor as described in any one of Claims 1-5. The adjustment of the pressure in the back pressure applying space is as follows:
Based on one or both of the detection result of the interval between the casing and the impeller in the radial direction, and the detection result of the pressure in the back pressure application space,
The geared compressor as described in any one of Claims 2-6. The split ring is
Provided upstream of the gas flowing direction in the housing space,
The geared compressor as described in any one of Claims 2-7.

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