Patent Application
20230139727
This disclosure relates generally to a centrifugal compressor. More specifically, this disclosure relates to an interstage throttle used in a multistage centrifugal compressor in a heating, ventilation, air conditioning, and refrigeration (HVACR) system.
A compressor can include multiple stages in series for compressing a working fluid. A centrifugal compressor can include an impeller in each of its stages for compressing the working fluid. For example, working fluid is compressed in a first stage, flows from the first stage to a second stage, and is then further compressed in the second stage to a higher pressure. A centrifugal compressor can be configured to guide the working fluid discharged from the first stage to the second stage. HVACR systems are generally used to heat, cool, and/or ventilate an enclosed space (e.g., an interior space of a commercial building or a residential building, an interior space of a refrigerated transport unit, or the like). A HVACR system can include a heat transfer circuit with a compressor configured to compress a working fluid flowing through the heat transfer circuit.
In an embodiment, an interstage throttle for a centrifugal compressor includes a flow guide plate, a throttle ring with teeth, a drive ring, and linkage assemblies. The flow guide plate includes a plurality of guide vanes that forms channels extending radially inward. The channels are configured to direct working fluid discharged from a first stage of the centrifugal compressor to an inlet of a second stage of the centrifugal compressor. The linkage assemblies connect the drive ring to the throttle ring such that rotation of the drive ring moves the throttle ring in an axial direction relative to the flow guide plate between a retracted position and an extended position. In the extended position, the teeth of the throttle ring are disposed in and partially block the channels.
In an embodiment, the teeth of the throttle ring block less of the channels in the retracted position than in the extended position.
In an embodiment, the throttle ring includes radial shafts and each of the linkage assemblies include pairs of a drive linkage and a support linkage connected to the radial shafts of the throttle ring. The drive linkage and the support linkage in each of the pairs are connected to the same respective one of the radial shafts on the throttle ring.
In an embodiment, the centrifugal compressing includes a housing. The flow guide plate, the throttle ring, and the drive ring are disposed within the housing. The drive linkages connect the drive ring to the throttle ring and are configured to transfer rotation of the drive ring into axial movement of the throttle ring. The support linkages connect the throttle ring to the housing and are configured to prevent rotation of the throttle ring.
In an embodiment, in each pair of drive linkage and support linkage, the drive linkage has a first end rotatably connected to the respective radial shaft on the throttle ring and a second end rotatably connected to a respective radial shaft on the drive ring.
In an embodiment, in each pair of drive linkage and support linkage, the support linkage has a first end connected to the respective radial shaft on the throttle ring and a second end connected to the housing of the interstage throttle.
In an embodiment, the centrifugal compressor includes an actuator and an actuation linkage assembly. The actuation linkage assembly connects the actuator to the drive ring. Extending of the actuator causes rotation of the drive ring. The retraction of the actuator causes an opposite rotation of the drive ring.
In an embodiment, the rotation of the throttle ring from the retracted position to the extended position is less than 5 degrees.
In an embodiment, the flow guide plate has a fixed position in the interstage throttle.
In an embodiment, a method of operating a centrifugal compressor includes compressing a working fluid to a first pressure in the first stage, and directing the working fluid discharged from the first stage to a second stage via channels in a interstage throttle. The interstage throttle includes a flow guide plate with a plurality of guide vanes. The guide vanes form the channels which extend radially inward. The interstage throttle also includes a throttle ring, a drive ring, and linkage assemblies that connect the drive ring to the throttle ring. The directing of the working fluid via the channels includes rotating the drive ring which moves the throttle ring in an axial direction relative to the flow guide plate between a retracted position and an extended position. The throttle ring in the extended position having teeth disposed in and partially blocking the channels.
In an embodiment, the method also includes further compressing the working fluid in the second stage from the first pressure to a second pressure.
In an embodiment, the rotating of the drive ring includes extending or retracting an actuator connected to the drive ring, the extending or retracting of the actuator causing the rotation of the drive ring.
In an embodiment, a centrifugal compressor includes a first stage, a second stage, and an interstage throttle fluidly connecting the first stage to the second stage. The first stage includes a first impeller configured to compress working fluid to a first pressure. The second stages a second impeller configured to compress the working fluid to a second pressure. The interstage throttle includes a flow guide plate, a throttle ring with teeth, a drive ring, and linkage assemblies. The flow guide plate includes a plurality of guide vanes that forms channels extending radially inward. The channels configured to direct working fluid discharged from a first stage of the centrifugal compressor to an inlet of a second stage of the centrifugal compressor. The linkage assemblies connect the drive ring to the throttle ring such that rotation of the drive ring moves the throttle ring in an axial direction relative to the flow guide plate between a retracted position and an extended position. In the extended position, the teeth of the throttle ring are disposed in and partially block the channels.
In an embodiment, the teeth of the throttle ring block less of the channels in the retracted position than in the extended position.
In an embodiment, the throttle ring includes radial shafts, each of the linkage assemblies include pairs of a drive linkage and a support linkage connected to the radial shafts of the throttle ring. The drive linkage and the support linkage in each of the pairs are connected to the same respective one of the radial shafts on the throttle ring.
In an embodiment, the centrifugal compressor also includes a housing. The flow guide plate, the throttle ring, and the drive ring are disposed within the housing. The drive linkages connect the drive ring to the throttle ring and are configured to transfer rotation of the drive ring into axial movement of the throttle ring. The support linkages connect the throttle ring to the housing and are configured to prevent rotation of the throttle ring.
In an embodiment, the centrifugal compressor also includes an actuator and an actuation linkage assembly connecting the actuator to the drive ring. Extending the actuator causes rotation of the drive ring, and retraction of the actuator causes the opposite rotation of the drive ring.
In an embodiment, the centrifugal compressor includes a housing. The flow guide plate, the throttle ring, and the drive ring are disposed within the housing. The actuator is external to the housing and the actuation linkage assembly extends through the housing.
In an embodiment, the rotation of the throttle ring from the retracted position to the extended position is less than 5 degrees.
In an embodiment, the flow guide plate is configured to have a fixed position within the centrifugal compressor.
Like reference numbers represent like parts throughout.
A heating, ventilation, air conditioning, and refrigeration (“HVACR”) system can include a heat transfer circuit configured to heat or cool a process fluid (e.g., air, water and/or glycol, or the like). The heat transfer circuit includes a compressor that compresses a working fluid circulated through the heat transfer circuit. The compressor includes a first stage with a first impeller and a second stage with a second impeller. The first stage configured to compress the working fluid to a first pressure and the second stage configured to further compress the working fluid discharged from the first stage. An interstage throttle directs the working fluid from the first stage to the inlet of the second stage.
Embodiments described herein are directed to interstate throttles in centrifugal compressors, centrifugal compressors with an interstage throttle, HVACR systems that include centrifugal compressors, and methods of operating centrifugal compressors.
The components of the heat transfer circuit 1 are fluidly connected. The heat transfer circuit 1 can be configured as a cooling system (e.g., a fluid chiller of an HVACR, an air conditioning system, or the like) that can be operated in a cooling mode, and/or the heat transfer circuit 1 can be configured to operate as a heat pump system that can run in a cooling mode and a heating mode.
The heat transfer circuit 1 applies known principles of gas compression and heat transfer. The heat transfer circuit can be configured to heat or cool a process fluid (e.g., water, air, or the like). In an embodiment, the heat transfer circuit 1 may represent a chiller that cools a process fluid such as water or the like. In an embodiment, the heat transfer circuit 1 may represent an air conditioner and/or a heat pump that cools and/or heats a process fluid such as air, water, or the like.
During the operation of the heat transfer circuit 1, a working fluid (e.g., refrigerant, refrigerant mixture, or the like) flows into the compressor 10 from the evaporator 40 in a gaseous state at a relatively lower pressure. The compressor 10 compresses the gas into a high pressure state, which also heats the gas. After being compressed, the relatively higher pressure and higher temperature gas flows from the compressor 10 to the condenser 20. In addition to the working fluid flowing through the condenser 20, a first process fluid PF1 (e.g., external air, external water, chiller water, or the like) also separately flows through the condenser 20. The first process fluid absorbs heat from the working fluid as the first process fluid PF1 flows through the condenser 20, which cools the working fluid as it flows through the condenser. The working fluid condenses to liquid and then flows into the expansion device 30. The expansion device 30 allows the working fluid to expand, which converts the working fluid to a mixed vapor and liquid state. An “expansion device” as described herein may also be referred to as an expander. In an embodiment, the expander may be an expansion valve, expansion plate, expansion vessel, orifice, or the like, or other such types of expansion mechanisms. It should be appreciated that the expander may be any type of expander used in the field for expanding a working fluid to cause the working fluid to decrease in temperature. The relatively lower temperature, vapor/liquid working fluid then flows into the evaporator 40. A second process fluid PF2 (e.g., air, water, or the like) also flows through the evaporator 40. The working fluid absorbs heat from the second process fluid PF2 as it flows through the evaporator 40, which cools the second process fluid PF2 as it flows through the evaporator 40. As the working fluid absorbs heat, the working fluid evaporates to vapor. The working fluid then returns to the compressor 10 from the evaporator 40. The above-described process continues while the heat transfer circuit 1 is operated, for example, in a cooling mode.
The compressor 100 also includes a driveshaft 112, a rotor 114, and a stator 116. The impellers 110A, 110B are each affixed to the driveshaft 112. For example, the first impeller 110A is affixed to an end of the driveshaft 112 while the second impeller 110B is affixed closer to a middle of the shaft 112. The rotor 114 is attached to the driveshaft 112 and is rotated by the stator 116, which rotates driveshaft 112 and the impellers 110A, 110B. The rotor 114 and stator 116 form an electric motor of the compressor 110. The electric motor (e.g., the stator 116 and the rotor 114) operates according to generally known principles. In another embodiment, the driveshaft 112 may be connected to and rotated by an external electric motor, an internal combustion engine (e.g., a diesel engine or a gasoline engine), or the like. It is appreciated that in such embodiments that the rotor 114 and the stator 116 would not be present within the housing 102 of the compressor 100. The driveshaft 112 extends through the first and second stages S1 and S2 as well as the interstage throttle 130 as shown in
The flow path F1 of working fluid through the compressor 100 is indicated in dashed arrows in
In flow path F1, the interstage throttle 130 is disposed between the first impeller 110A of the first stage S1 and the second impeller 110B of the second stage S2. The interstage throttle 130 is disposed between the outlet 118 of the first impeller S1 and the inlet 120 of the second impeller 110A. The driveshaft 112 extends through the interstage throttle 130. The interstage throttle 130 fluidly connects the outlet 118 of the first impeller 110A to the inlet 120 of the second impeller 110B. The interstage throttle 130 directs the working fluid discharged from the first stage S1 (e.g., the compressed working fluid at the first pressure P1) to the second impeller 110B of the second stage S2. For example, the interstage throttle 130 directs the compressed working fluid (after being discharged radially outward from the first impeller 110A) radially inward to the inlet 120 of the second impeller 110B. The interstage throttle 130 is adjustable to control the flowrate of the compressed working fluid flowing from the first stage S1 to the second stage S2. The interstage throttle 130 includes an actuator 170 for operating the interstage throttle 130. The actuator 170 is operable/actuates to adjust the flowrate of the compressed working fluid flowing through the interstage throttle 130. For example, a controller (not shown) of the compressor 100 and/or the HVACR controller may be configured to control the capacity of the compressor 100 by controlling the position/actuation of the actuator 170.
The interstage throttle 130 includes guide vanes 144 and channels 146 formed by the guide vanes 144. The channels 146 spiral radially inward and are shown in more detail in
The throttle ring 160 includes teeth 162 that extend towards the flow guide plate 140. The throttle ring 160 is configured to be actuated in the axial direction (e.g., in direction D1, in direction D2) relative to the channels 146. The axial movement of the throttle ring 160 changes the length of the teeth 162 disposed in the channels 146 to adjust the cross-sectional area of the channels 146. For example, when the throttle ring 160 is actuated towards the channels 146 (e.g., in a positive axial direction D1), the teeth 162 extend further into the channels 146 and reduce the cross-sectional area of the channels 146. As each tooth 162 is disposed further into its respective channel 146, the tooth 162 partially blocks more of the channel 146 and decreases the cross-sectional area of the channel 146 (e.g., decreases the open cross-sectional area in each channel). The decreased cross-sectional area of the channels 146 decreases the flowrate of the working fluid through the channels 146 and the interstage throttle 130. When the throttle ring 160 is actuated away from the channels 146 (e.g., in the negative axial direction D2), the teeth 162 extend less into the channels 146 and the cross-sectional area of the channels 146 is increased, which increases the flow of the working fluid through the interstage throttle 130. For example, the throttle ring 160 in an embodiment may have a retracted position in which the teeth 162 disposed entirely outside of the channels 146. The configuration of the interstage throttle 130 is discussed in more detail below.
The actuation linkage assembly 172 connects to the actuator 170 and extends through the housing 132. The actuator 170 actuates the actuation linkage assembly 172 to actuate/move the throttle ring 160 within the housing 132. For example, the actuation linkage assembly 172 includes a shaft 174 that extends through the housing 132. The actuator 170 actuates (e.g., extends, retracts) to rotate the shaft 174. As shown in
The flow guide plate 140 includes a baseplate 142 and the guide vanes 144 that extend along the baseplate 142. The guide vanes 144 are provided on the baseplate 142. The flow guide plate 140 includes through-hole 149 for the driveshaft 112 (shown in
The actuation mechanism 99 for the throttle ring 130 includes the actuation linkage assembly 172, a drive ring 180, drive linkages 182, and support linkages 184. In the illustrated embodiment, the actuation linkage assembly 172 includes the shaft 174 and is configured to utilize the motion of the actuator 170 (e.g., linear motion, extension, retraction, etc.) to rotate the drive ring 180. For example, the linear extension of actuator 170 rotates the shaft 172 of the actuation linkage assembly 170 and the rotation of the shaft 172 in turn rotates the drive ring 180. As shown in
The linkages 182, 184 are configured to move the throttle ring 160 in the axial direction (e.g., positive axial direction D1, negative axial direction D2) using the rotation of the drive ring 180. The drive linkages 182 connect the drive ring 180 to the throttle ring 160. Each of the drive linkages 182 separately extends from the drive ring 180 to the throttle ring 160. As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
When actuated into the extended position as shown in
When moved to the extended position, the teeth 162 partially block the channels 146 and reduce the open height H of the channels. The blocking of the channels 146 reduces their open cross sectional area A2 at the teeth 162. This creates a pressure drop for the working fluid to flow through the smaller cross sectional area A2 which reduces the flow rate of the working fluid through the channels 146 (e.g., the flow rate of the working fluid through the interstage throttle 130).
In the illustrated embodiment, the drive linkage 282 is a slot in the drive ring 280. A radial shaft 264 of the throttle ring 260 extends through the slot. The slot is angled between the axial direction D1 and circumferential direction D3 such that the rotation of drive ring 280 forces the radial shaft 264 to move axially within the slot which moves the throttle ring 260 in the axial direction D1. In
At 1010, working fluid is compressed in and discharged from a first stage (e.g., first stage S1) of the compressor. Compressing the working fluid in the first stage 1010 may include rotating a first impeller (e.g., first impeller 110A) of the first stage 1012. The rotating of the first impeller at 1012 compresses the working fluid from an inlet pressure to a higher pressure (e.g., first pressure) and radially discharges the compressed working fluid from the first impeller 110A at the first pressure 1012. The method 1010 then proceeds from 1010 to 1020.
At 1020, the compressed working fluid is directed from the first stage to a second stage of the compressor (e.g., second stage S2) via channels (e.g., channels 146) in an interstage throttle (e.g., interstage throttle 130). The compressed working fluid flowing from the first stage to the second stage through the channels in the interstage throttle. Directing the compressed working fluid at 1020 includes actuating the interstage throttle 1022 to control the flow (e.g., flowrate) of the working fluid to the second stage. Actuating the interstage throttle at 1022 includes axially moving a throttle ring of the interstage throttle (e.g., throttle ring 160, 260) 1024. Actuating the throttle ring at 1024 includes rotating a drive ring (e.g., drive ring 180) connected to the throttle ring. The rotation of the drive ring moving the throttle ring in an axial direction closer to the channels. For example, the movement of the throttle ring in the axial direction closer to the channels reduces the cross-sectional areas (e.g., area A1, area A2) of the channels and reduces the flowrate of the working fluid through the interstage throttle 130. The compressor (e.g., a controller of the compressor) is configured to adjust the position of the interstage throttle 130 to control the capacity of the compressor (e.g., the volumetric discharge from the compressor) to match a desired capacity based on the cooling or heating to be provided by the HVACR system (e.g., heating or cooling to be provided by the heat transfer circuit 1).
It should be appreciated that the method 1000 in an embodiment may be modified to have features as discussed above for the compressor 10 in
Any of Aspects 1-9 can be combined with any of Aspects 10-20 and any of aspects 10-12 can be combined with Aspects 13-20.
Aspect 1. An interstage throttle for a centrifugal compressor including a first stage and a second stage, the interstage throttle comprising: a flow guide plate including a plurality of guide vanes forming channels extending radially inward, the channels configured to direct working fluid discharged from the first stage to an inlet of the second stage; a throttle ring including teeth; a drive ring; linkage assemblies connecting the drive ring to the throttle ring such that rotation of drive ring moves the throttle ring in an axial direction relative to the flow guide plate between a retracted position and an extended position, wherein in the extended position, the teeth of the throttle ring are disposed in and partially block the channels.
Aspect 2. The interstage throttle of Aspect 1, wherein the teeth of the throttle ring block less of the channels in the retracted position than in the extended position.
Aspect 3. The interstage throttle of any one of Aspects 1 and 2, wherein the throttle ring includes radial shafts, each of the linkage assemblies include pairs of a drive linkage and a support linkage connected to the radial shafts of the throttle ring, the drive linkage and the support linkage in each of the pairs connected to the same respective one of the radial shafts on the throttle ring.
Aspect 4. The interstage throttle ring any one of Aspect 3, further comprising: a housing, the flow guide plate, the throttle ring, and the drive ring disposed within the housing, wherein the drive linkages connect the drive ring to the throttle ring, the drive linkages configured to transfer rotation of the drive ring into axial movement of the throttle ring, and the support linkages connect the throttle ring to the housing, the support linkages configured to prevent rotation of the throttle ring.
Aspect 5. The interstage throttle ring of any one of Aspects 3 and 4, wherein in each of the pairs of the drive linkage and the support linkage: the drive linkage has a first end rotatably connected to the respective radial shaft on the throttle ring and a second end rotatably connected to a respective radial shaft on the drive ring.
Aspect 6. The interstage throttle ring of any one of Aspects 3-5, wherein in each of the pairs of the drive linkage and the support linkage: the support linkage has a first end connected to the respective radial shaft on the throttle ring and a second end connected to a housing of the interstage throttle.
Aspect 7. The interstage throttle of any one of Aspects 1-6, further comprising: an actuator and an actuation linkage assembly connecting the actuator to the drive ring, actuation of the actuator extends the actuator causes rotation of the drive ring, and retraction of the actuator causes opposite rotation of the drive ring.
Aspect 8. The interstage throttle of any one of Aspects 1-7, wherein rotation of the throttle ring from the retracted position to the extended position is less than 5 degrees.
Aspect 9. The interstage throttle of any one of Aspects 1-8, wherein the flow guide plate is configured to have a fixed position in the interstage throttle.
Aspect 10. A method of operating a centrifugal compressor, comprising: compressing a working fluid to a first pressure in the first stage; directing the working fluid discharged from the first stage to a second stage via channels in a interstage throttle, the interstage throttle including a flow guide plate including a plurality of guide vanes forming the channels extending radially inward, a throttle ring, a drive ring, and linkage assemblies connecting the drive ring to the throttle ring, wherein the directing of the working fluid via the channels includes: rotating the drive ring to move the throttle ring in an axial direction relative to the flow guide plate between a retracted position and an extended position, the rotation of the drive ring moving the throttle ring between in the axial direction between the retracted position and the extended position, the throttle ring in the extended position having teeth disposed in and partially blocking the channels.
Aspect 11. The method of Aspect 10, further comprising: further compressing the working fluid in the second stage from the first pressure to a second pressure.
Aspect 12. The method of any one of Aspects 10 and 11, wherein the rotating of the drive ring includes extending or retracting an actuator connected to the drive ring, the extending or retracting of the actuator causing rotation of the drive ring.
Aspect 13. A centrifugal compressor, comprising: a first stage including a first impeller configured to compress working fluid to a first pressure; a second stage including a second impeller configured to compress the working fluid to a second pressure; an interstage throttle fluidly connecting the first stage to the second stage, the interstage throttle including: a flow guide plate including a plurality of guide vanes forming channels extending radially inward, the channels configured to direct the working fluid discharged from the first stage at the first pressure to an inlet of the second stage, a throttle ring including teeth, a drive ring, and linkage assemblies connecting the drive ring to the throttle ring such that rotation of the drive ring moves the throttle ring in an axial direction relative to the flow guide plate between a retracted position and an extended position, wherein in the extended position, the teeth of the throttle ring are disposed in and partially block the channels.
Aspect 14. The centrifugal compressor of Aspect 13, wherein the teeth of the throttle ring block less of the channels in the retracted position than in the extended position.
Aspect 15. The centrifugal compressor of any one of Aspects 13 and 14, wherein the throttle ring includes radial shafts, each of the linkage assemblies include pairs of a drive linkage and a support linkage connected to the radial shafts of the throttle ring, the drive linkage and the support linkage in each of the pairs connected to the same respective one of the radial shafts on the throttle ring.
Aspect 16. The centrifugal compressor of Aspect 15, further comprising: a housing, the flow guide plate, the throttle ring, and the drive ring disposed within the housing, wherein the drive linkages connect the drive ring to the throttle ring, the drive linkages configured to transfer rotation of the drive ring into axial movement of the throttle ring, and the support linkages connect the throttle ring to the housing, the support linkages configured to prevent rotation of the throttle ring.
Aspect 17. The centrifugal compressor of any one of Aspects 13-16, further comprising: an actuator and an actuation linkage assembly connecting the actuator to the drive ring, actuation of the actuator extends the actuator causing rotation of the drive ring, and retraction of the actuator causes opposite rotation of the drive ring.
Aspect 18. The centrifugal compressor of Aspect 17, further comprising: a housing, wherein the flow guide plate, the throttle ring, and the drive ring are disposed within the housing, the actuator is external to the housing, and the actuation linkage assembly extends through the housing.
Aspect 19. The centrifugal compressor of any one of Aspects 13-18, wherein rotation of the throttle ring from the retracted position to the extended position is less than 5 degrees.
Aspect 20. The centrifugal compressor of any one of Aspects 13-19, wherein the flow guide plate is configured to have a fixed position within the centrifugal compressor.
The terminology used herein is intended to describe particular embodiments and is not intended to be limiting. The terms “a,” “an,” and “the” include the plural forms as well, unless clearly indicated otherwise. The terms “comprises” and/or “comprising,” when used in this Specification, specify the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components. In an embodiment, “connected” and “connecting” as described herein can refer to being “directly connected” and “directly connecting”.
With regard to the preceding description, it is to be understood that changes may be made in detail, especially in matters of the construction materials employed and the shape, size, and arrangement of parts without departing from the scope of the present disclosure. This Specification and the embodiments described are exemplary only, with the true scope and spirit of the disclosure being indicated by the claims that follow.
