JPS6218719Y2 - - Google Patents

Abstract

A diffuser control (26) for controlling vapor flow through a diffuser passage (16) comprising an annular recess (28) defined by a housing (12) of the diffuser passage (16) and in communication therewith, and an annular control ring (30) supported for movement within the recess (28) and the diffuser passage (16) between a throttling position, wherein the control ring (30) throttles vapor flow through the diffuser passage (16), and an open position for permitting a substantially free flow of vapor through the diffuser passage (16). The diffuser control (26) further comprises a plurality of springs (32) supported by the housing (12) for urging the control ring (30) toward the throttling position, a stop (34) for limiting movement of the control ring (30) at the throttling position, a low pressure conduit (38) for connecting the annular recess (28) to a low pressure source, and a steal (42, 44) for retarding vapor flow from a higher pressure side of the control ring (30) to a lower pressure side thereof when the control ring (30) is in the open position. A valve (40) is provided for regulating vapor flow through the low pressure conduit (38) and includes a first position for maintaining a low pressure in the annular recess (28) and a pressure difference across the control ring (30) for maintaining the control ring (30) in the open posiiton, and a second position for maintaining a high pressure in the annular recess (28) wherein the springs (32) maintain the control ring (30) in the throttling position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to centrifugal vapor compressors, and more particularly to a differential user control device for controlling vapor flow through a differential user passage of a centrifugal vapor compressor.

One of the important problems that arises when using centrifugal compressors in applications where the compressor load varies over a wide range is the problem of stabilizing the flow through the compressor. The compressor inlet, impeller and diffuser passages must be dimensioned to accommodate the maximum volumetric flow rate required.
However, if the volumetric flow rate through such a compressor is low, the flow becomes unstable. As the volumetric flow rate decreases from the stable range, a slightly unstable flow range is entered. In this range, a partial flow reversal appears in the diffuser passage, creating noise and reducing compressor efficiency. If the flow rate decreases further than this range, the compressor will experience a so-called surge phenomenon, in which periodic complete backflow occurs in the diffuser passages, destroying the efficiency of the machine and endangering the integrity of its components. It will be destroyed. Since it is often desirable to widen the volumetric flow range of a compressor, many improvements have been proposed in the past to increase flow stability at low volumetric flow rates. One of the most widely accepted and well-recognized improvements is the addition of guide vanes within the compressor inlet to alter the flow direction and amount of incoming steam. Another widely known improvement is to change the configuration (opening) of the differential user in response to the load on the compressor. This operation is generally accomplished by a diff user control ring that moves transversely across the diff user passageway and serves to throttle the steam flow in the passageway.
Conventional variable differential user control rings are controlled by a mechanism that positions and holds the ring anywhere between a fully open position and a fully closed position. Such control mechanisms are relatively expensive to manufacture and require fairly complex mechanical and/or pneumatic components. Furthermore, because conventional diffusing control mechanisms use complex parts, their manufacturing and installation operations are difficult and time-consuming operations that require skilled labor. While a continuously variable differential user control ring certainly performs well, it has been found that very good results can also be obtained with a differential user control ring having a limited number of stepped aperture positions. The stepwise variable differential user control device according to the present invention not only performs very satisfactorily, but also has a much simpler structure than conventional control devices. This simple structure is
To facilitate manufacturing, installation, and maintenance of a differential user control device, reduce costs thereof, and increase reliability thereof.

Briefly, the present invention's differential user control device for controlling vapor flow in a differential user includes an annular recess defined by a housing of the differential user passageway and communicating with the differential user passageway, and a maximum throttle position that throttles the vapor flow through the differential user passageway. and a minimum aperture position, supported so as to be movable within the recess and the diff user passage,
an annularly radially extending front surface, an outer axial surface extending rearwardly from a radially outer edge of the front surface spaced from the housing to facilitate movement within the differential user passageway; a differential user restriction means having an inner axial surface spaced from the housing and extending rearwardly from a radially inner edge of the front surface to facilitate movement within the passage; first pressing means 32 for pressing said restricting means towards said maximum throttle position, and conduit means 38 for connecting said annular recess 28 to a low pressure source, when said restricting means is in a minimum throttle position. a first sealing means for inhibiting the flow of steam from the high pressure side to the low pressure side of the restriction means; and a first sealing means for regulating the flow of steam through the conduit means, the restriction means being at its minimum constriction position. a first position for maintaining a low pressure in the annular recess so as to maintain a pressure difference between the front side and the rear side of the restriction means; a second position for maintaining a high pressure in the annular recess so as to be held in a maximum throttle position; and a stop means for restricting movement of the limiting means to the maximum throttle position. , a second pressing means supported by the housing and for pressing the differential user restriction means toward an intermediate aperture position between the minimum aperture position and the maximum aperture position; force limiting means for limiting the force exerted on the means at the intermediate throttle position; and for inhibiting steam flow from the high pressure side to the low pressure side of the differential user limiting means when the differential user limiting means is placed in the intermediate throttle position. a second sealing means extending radially outwardly from the outer axial surface of the differential user restriction means integrally with the differential user restriction means and within the annular recess 28; an outer annular flange extending radially inwardly from the inner axial surface of the restriction means integrally with the restriction means and located within the annular recess; a first annular sealing surface on the housing behind the inner annular flange; and a second annular sealing surface on the housing behind the inner annular flange, the differential user limiting means being in a minimum throttle position. When provided, the outer annular flange and the inner annular flange abut the first sealing surface and the second sealing surface, respectively, to control rearward movement of the differential user restriction means, and steam flows from the differential user passageway to the differential user restriction means. configured to prevent leakage to the rear through the
The valve device is arranged in the annular recess 28 to maintain the differential user restriction means in the intermediate throttle position.
and a third position for maintaining an intermediate pressure within the restrictor and a second pressure differential between the front and rear sides of the restriction means.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1, a portion of a vapor compressor constructed in accordance with the present invention is shown. Compressor 10
is a well-known centrifugal compressor in which steam to be compressed is guided axially to a bladed impeller.
The impeller is connected to a suitable drive for imparting rotational movement. Steam is directed radially from the impeller to a diffuser passage communicating with its tip while being compressed through a compressor. Compressor 10 includes a housing 12 having an inlet passage 14 and a diffuser passage 16. Housing 12, only a portion of which is shown, is of conventional construction in devices of this type. A shaft 20 is connected by a nut 22 between the inlet passage 14 and the diffuser passage 16 in the housing 12.
An impeller 18 attached to the impeller 18 is disposed. Entrance passage 1
4 to control the direction and amount of steam passing through the
A plurality of inlet guide vanes 24 rotatably supported by the housing 12 are disposed around the inlet passageway 14. A differential user control device 26 is also provided to control the steam flow through the differential user passageway 16.

The differential user control device 26 is connected to the housing 12
an annular recess 28 defined by and communicating with the differential user passage 16; and an annular control ring 3, for example.
0-shaped differential user restriction means.
The control ring 30 has three stable positions within the annular recess 28 and the differential user passage 16: an open position as shown in FIG. 1, an intermediate throttle position as shown in FIG. 2, and a full throttle position as shown in FIG. support so that it can be moved between In the full throttle position, control ring 30 throttles vapor flow through diffuser passage 16. In the open position, the ring 30
Allows unrestrained flow of steam flow through the diff user passage. First pressing means 32 are provided for biasing the control ring 30 towards the throttle position. The first pressing means 32 includes a plurality of springs 32 disposed within the recess 28.
Preferably, it is an elastic means such as. Spring 3
2 are preferably equally spaced around the circumference of the control ring 30 to form a spring ring with a radius equal to the radius of the ring 30. To prevent the control ring 30 from completely blocking steam flow through the diffuser passage 16, a stop means 34 is provided to control movement of the control ring at the full throttle position. Preferably, the stop means 34 is formed by a surface of the housing 12. That is, as the control ring 30 advances from left to right in the illustration and reaches the full throttle position, the control ring flange 36 abuts the stop surface 34, thereby preventing further advancement of the control ring. .

A second pressing means 50 is provided for pressing the control ring 30 towards an intermediate throttle position (FIG. 2) between the open position and the full throttle position. The second pressing means includes, for example, a plurality of second springs 50 disposed within the annular recess 28.
It is preferable that the second elastic means is used. Preferably, the second springs 50 are equally spaced around the circumference of the control ring 30 and define a second spring ring with a radius equal to the radius of the ring 30. In the illustrated embodiment, each first spring 32 and second spring 50 are generally cylindrical in shape, with the second spring concentrically surrounding the first spring. Force limiting means 52 are provided for limiting the force exerted on the control ring 30 by the second spring 50 in the intermediate throttle position. In the illustrated embodiment, the force limiting means 52 includes a plurality of movable rings 54.
and stop means, such as a plurality of stationary rings 56 secured to the housing 12 and projecting into the annular recess 28. The ring 54 is sandwiched between the second spring 50 and the fingers 57 of the control ring 30;
It is slidably supported within the recess 28 . Each second spring 5
0 impinges on the corresponding ring 54 and is thereby maintained to the left of the ring 54. Each first spring 3
2 is slidable inside the ring 54, and the ring 54 does not interfere with the movement of the first spring 32.

When the control ring 30 moves from the open position to the intermediate throttle position, the ring 54 abuts the fingers 57 of the control ring 30 and transmits the pressing force of the spring 50 to the control ring 30. When the control ring 30 reaches the intermediate throttle position as shown in FIG. 2, the movable ring 54 abuts the stationary ring 56 and is prevented from further forward or rightward movement. However, the control ring 30 is free to move further to the right and is pushed to the right by the action of the first spring 32.
When the control ring 30 moves from the intermediate aperture position to the full aperture position, the movable ring 54 and the spring 50 disengage from the control ring 30. As a result, the transmission of force from the second spring 50 to the ring 30 is interrupted.

Diff user control 26 further includes a low pressure conduit 38 for connecting annular recess 28 to a pressure source lower than the pressure in diff user passageway 16, such as a suction pipe of compressor 10, and a low pressure conduit 38 for connecting annular recess 28 to an intermediate pressure source. conduit means 37 including an intermediate pressure conduit 58; For example, if compressor 10 is a multi-stage compressor, the intermediate pressure source may be an intermediate stage of the compressor. The valve arrangement 39 is for regulating the steam flow through the conduit means 37 and comprises a first valve 40 disposed in the low pressure conduit 38 and a second valve 62 disposed in the intermediate pressure conduit 58. It is equipped with a valve 40
and 62 cooperate to establish a first position for maintaining a low pressure within the annular recess 28, a second position for maintaining an intermediate pressure, and a third position for maintaining a high pressure. The first position to maintain low pressure is
This is preferably done by opening the first valve 40 to preferably fully open the low pressure conduit 38 and closing the second valve 62. A low pressure is thereby maintained within the annular recess 28. This low pressure is sufficiently lower than the pressure within the differential user passage 16, and when the low pressure is maintained within the recess 28, the first pressure exerted on the control ring 30 due to the pressure difference between the recess and the differential user passage is 32 and 5
0 on the control ring, such that this first pressure holds the control ring in the open position.

The second position of the valve arrangement 39 is preferably set by closing the first valve 40 and opening the second valve 62 to open the intermediate pressure conduit 58. When an intermediate pressure is maintained in the recess 28, the second pressure acting on the control ring 30 is less than the force exerted on the control ring by the springs 32 and 50;
The force exerted on the control ring by spring 32 alone should be greater. This second pressure holds the control ring in the intermediate throttle position.

The third position of the valve device 39 is located between the first valve 40 and the second valve.
Preferably, this is done by closing both valves 62 and closing the low pressure conduit 38 and intermediate pressure conduit 58. As steam thereby flows from the diff user passage 16 into the annular recess 28 and a high pressure is maintained within the recess, a force is exerted on the control ring 30 by the pressure difference between the recess 28 and the diff user passage 16. is less than the force exerted on the control ring by the first spring 32, and the control ring is held by the spring 32 in the full throttle position.

The first valve 40 and the second valve 62 are operated by positioning means 41 and 66 of a suitable type, for example electrical, pneumatic or hydraulic positioners. The positioning means 41, 66 operate in response to the operating conditions of the compressor 10 or in response to an associated device indicating the load on the compressor. For example, when the compressor 10 is used in a refrigeration system,
The positioning means 41, 66 can be actuated in response to the temperature of the chilled water exiting the refrigeration system. The temperature of the cooled water is related to the amount of refrigerant delivered by the compressor from the low pressure side to the high pressure side of the refrigeration system. When the compressor 10 is used to compress air, the positioning means 41, 66
can be activated in response to ambient temperature. This is because the ambient temperature indicates the density of the air to be compressed, and therefore the amount of air.

Preferably, however, the position of valves 40 and 62 is determined by the position of guide vane 24 as detected by sensor 43. Sensor 43 may be configured, for example, to actuate a limit switch (see FIG. (not shown).

The operation of the compressor 10 equipped with the above-described differential user control device 26 is as follows. When valves 40 and 62 are in the first position, low pressure conduit 38 is opened and intermediate pressure conduit 58 is closed by valve 62, annular recess 28 communicates with the low pressure source via conduit 38 and the recess The pressure within 28 will be approximately equal to the pressure of the low pressure source. Then, the vapor pressure in the recess 28 becomes lower than the vapor pressure in the differential user passage 16, and a pressure difference is created between the front side of the control ring 30, that is, the side of the differential user passage, and the rear side, that is, the side of the recess, and the control ring moves rearward. , that is, it is pushed to the left in the figure. This low pressure source means that the force exerted on control ring 30 by the pressure difference across it when valve 40 is open and valve 62 is closed is greater than the force exerted on the ring by springs 32 and 50. selected to be large. Thus, the force of the steam pressure overcomes the force of the spring and moves the control ring 30 to and holds it in the open position, causing the differential user passageway 16 to move and remain in the open position.
Maximize steam flow through.

A second stop means 64 may be provided to limit rearward movement of the control ring 30. Preferably, the second stop means is constituted by the surface 64 of the stationary ring 56. As the control ring 30 moves rearwardly and reaches the open position, the flange 70 of the control ring abuts the surface 64, thereby preventing further rearward movement of the ring 30. According to this configuration, the flange 70 and the surface 64, when in abutting engagement as described above, act as a sealing means to inhibit the flow of steam from the high pressure side, or right side, to the low pressure side, or left side, of the control ring 30. It also plays the role of

To move control ring 30 to the intermediate throttle position shown in FIG.
to open the intermediate pressure conduit 58. The operation of the valves 40 and 62 is performed by, for example, the guide vane 24
may occur in response to being moved to a predetermined position restricting vapor flow through the compressor 10. Thus, the recess 28 communicates with the intermediate pressure chamber via the conduit 38, the pressure within the recess is increased to approximately the same pressure as the intermediate pressure source, and the pressure difference across the control ring 30 is reduced. . This intermediate pressure source is selected such that the steam pressure force on control ring 30 when valve 40 is closed and valve 62 is open is less than the force exerted on the ring by springs 32 and 50. . The control ring 30 thus moves from the open position towards the intermediate aperture position.

When the control ring 30 reaches the intermediate aperture position shown in FIG.
The movable ring 54 and the second spring 50 are prevented from moving further. Therefore, the second spring 50 does not push the control ring 30 further to the right. Only the first spring 32 continues to press the control ring to the right. However, the intermediate pressure source
The steam pressure force exerted on control ring 30 as a result of the pressure difference across it when valve 40 is closed and valve 62 is open is greater than the force exerted on the ring by second spring 50 alone. It is chosen to be large. That is, the force exerted by the first spring 32 is not sufficient to move the control ring 30 to the right, and the second spring 50 pushes the control ring to the right due to the impact between the rings 54 and 56. Also, the pressure differential across the control ring is not sufficient to move the control ring to the left against the combined force of springs 32 and 50. Therefore,
Control ring 30 is held in an intermediate aperture position.
In this position, the control ring 30 throttles the steam flow through the diffuser passage 16 to establish a stable steam flow at a reduced flow rate. Furthermore, control ring 3
0 is at the intermediate aperture position, the movable ring 54
impinges on both the stationary ring 56 and the finger 57 of the control ring, and the rings 54, 56 and the finger 57
7 serves as a sealing means to prevent the flow of steam from the high pressure side or right side of the control ring 30 to the low pressure side or left side.

To move control ring 30 to the fully throttled position shown in FIG. 3, low pressure conduit 38 and intermediate pressure conduit 58 are closed by valves 40 and 62, respectively. This operation may occur, for example, in response to guide vane 24 being moved to a second predetermined position that further restricts vapor flow through compressor 10. Steam flows from the diff user passage 16 through the interface between the fingers 57 and the movable ring 54 into the annular recess 28, where the steam pressure in the recess and the vapor pressure in the diff user passage are balanced and the steam flows into the annular recess 28. As a result, the steam pressure forces acting on the control ring 30 are balanced. Thus, the force of the spring 32 prevails and forces the control ring 30 into the diffuser passageway to its full throttle position. At this full throttle position, the flange 3
6 abuts the surface 34 and further forward movement of the control ring is prevented. Control ring 30 in this position further throttles the vapor flow through diffuser passage 16 to maintain a stable vapor flow through compressor 10 even at a further reduced rate.

The three-position control ring configuration of the present invention allows the differential user passage 16 to be controlled over a wide range of compressor load fluctuations.
Provide a steady flow of steam through the Furthermore, the differential user control device 26 does not require the complex mechanical and pneumatic elements of conventional differential user control devices, making it easy to manufacture and install, thus reducing the manufacturing cost of the differential user control device. This increases device reliability and eases manufacturing and installation. Moreover, the control device 26 of the present invention is simple in structure and is very suitable for integration into existing compressors, especially since there is no complex mechanical linkage for interlocking the control device with, for example, the guide vanes 24. There is.

[Brief explanation of the drawing]

Figure 1 is an elevational sectional view of a portion of a centrifugal compressor incorporating the three-position differential user control device of the present invention;
3 are partial cross-sectional views showing the control ring of the compressor of FIG. 1 in intermediate and full throttle positions, respectively; FIG. In the figure, 10 is a compressor, 12 is a housing, and 14
16 is an inlet passage, 16 is a differential user passage, 18 is an impeller, 24 is a guide vane, 26 is a differential user control device, 28 is an annular recess, 30 is a control ring, 3
2 is a first pressing means (spring), 34 is a first stopping means, 37 is a conduit means, 38 is a low pressure conduit, 39 is a valve device, 40 is a valve, 44 is a flange, 50 is a second pressing means, 52 is a force Restricting means, 54 is a movable ring (transmission member), 56 is a stationary ring (stopping means), 5
8 is an intermediate pressure conduit, 62 is a valve, 64 is a second stop means, and 70 is a flange.

Claims (1)

[Claims for Utility Model Registration] 1. A differential user control device for controlling steam flow passing through the differential user passage 16, comprising: an annular recess 28 defined by the housing 12 of the differential user passage 16 and communicating with the differential user passage; an annularly radially extending front surface supported movably within the recess and the diff user passage between maximum and minimum throttling positions for throttling steam flow through the diff user passage; an outer axial surface extending rearwardly from the radially outer edge of the front surface away from the housing to facilitate movement; and from the housing to facilitate movement within the differential user passageway. a differential user limiting means 30 having an inner axial surface spaced apart and extending rearwardly from the radially inner edge of the front surface and supported by said housing 12 to limit said limiting means 30 to said maximum aperture position; conduit means 37 for connecting said annular recess 28 to a low pressure source; from the high pressure side of said restriction means to the low pressure side when said restriction means is in the minimum throttle position; first sealing means 64, 70 for restricting the flow of steam through said conduit means 37, said restricting means being maintained in its minimum throttle position; a first position for maintaining a low pressure in the annular recess and a pressure difference between the front side and the rear side of the restriction means, and the restriction means is held in a maximum throttle position by the first pressing means 32; a second position for maintaining a high pressure in the annular recess so as to be controlled; a stop means 34 for limiting the movement of said limiting means 30 to a maximum throttle position; a second pressing means 50 supported by the housing 12 for pressing the differential user limiting means 30 towards an intermediate aperture position between the minimum aperture position and the maximum aperture position;
Diff user restriction means 3 by the second pressing means
force limiting means 52 for limiting the force exerted on the differential user at the intermediate throttle position, and for inhibiting steam flow from the high pressure side to the low pressure side of the differential user limiting means when the differential user limiting means is placed in the intermediate throttle position. second sealing means 54, 56 for
The first sealing means 64, 70 are comprised of:
an outer annular flange 70 extending radially outwardly from the outer axial surface of the limiting means and located within the annular recess 28; an inner annular flange extending radially inwardly from said inner axial surface of the restriction means and located within said annular recess; and a first annular flange provided in said housing 12 rearwardly of said outer annular flange 70. a sealing surface 64 and a second annular sealing surface provided on the housing behind the inner annular flange, the outer annular flange 70 and Inner annular flanges abut the first sealing surface 64 and the sealing surface, respectively, to control rearward movement of the differential user restriction means and to permit steam to exit rearwardly from the differential user passageway 16 through the differential user restriction means 30. configured to prevent
The valve device 39 maintains an intermediate pressure within the annular recess 28 to maintain the differential user restriction means in the intermediate throttle position and maintains a second pressure difference between the front side and the rear side of the restriction means. A differential user control device having a third position for use. 2. Utility model registration characterized in that the conduit means includes a low pressure conduit 38 for connecting the annular recess 28 to the low pressure source, and an intermediate pressure conduit 58 for connecting the recess to the intermediate pressure source. A differential user control device according to claim 1. 3 such that when the valve device 39 is placed in the first position the intermediate pressure conduit 58 is closed and the low pressure conduit 38 is opened, and when the valve device is placed in the second position Practical practice characterized in that the low pressure and intermediate pressure conduits are configured to be closed and such that when the valve device is placed in the third position the low pressure conduit is closed and the intermediate pressure conduit is opened. Scope of patent registration request No. 2
The differential user control device described in Section 1. 4. The force limiting means 52 includes a movable transmission member 54 for transmitting force from the second pressing means 50 to the differential user limiting means 30 when the differential user limiting means 30 moves from the open position to the throttle position; a third stop means 56 for limiting movement of said transmission member 54 when said limiting means is placed in said intermediate aperture position;
When the differential user limiting means moves from the intermediate aperture position to the full aperture position, the transmission member
The differential user control device according to claim 3, wherein the differential user control device is configured to be separated from the differential user limiting device so as to prevent the force from being transmitted from the pressing device 52 to the differential user limiting device. . 5. The first pressing means comprises an elastic means 32 disposed within the annular recess 28, and the second pressing means comprises a second elastic means 50 disposed within the annular recess.
A differential user control device according to claim 4, characterized in that the device comprises: 6. The transmission member includes the second elastic means 50 and the differential user restriction means 30 within the annular recess 28.
A ring 5 supported so as to be able to slide between
5. The differential user control device according to claim 5, wherein the third stop means comprises a ring 56 fixed to the housing 12 and protruding into the annular recess. 7. The first elastic means comprises a plurality of first springs 32, and the second elastic means comprises a plurality of second springs 5 disposed between the first springs and adjacent to the first springs.
The differential user control device according to claim 6, characterized in that the differential user control device consists of 0.