Volume ratio control system for compressor

Abstract

A volume ratio control system for a compressor includes a chamber formed within a housing of the compressor, wherein the chamber is in fluid communication with a high pressure side of the compressor; a piston disposed within the chamber, wherein the piston includes a cavity in fluid communication with a low pressure side of the compressor; and a biasing device disposed within the chamber and configured to enable the piston to move in response to a pressure difference between the low pressure side of the compressor and the high pressure side of the compressor falling below a threshold.

Description

[0001] This application is a divisional application of the Chinese invention patent application with an application date of January 7, 2021, an international application number of PCT / US2021 / 012451, a national application number of 202180012173.3, and an invention name of “Volume Ratio Control System for Compressor”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to and the benefit of U.S. Provisional Application No. 62 / 958,204, filed on January 7, 2020, entitled “VOLUMERATIO CONTROL SYSTEM FOR A COMPRESSOR,” which is incorporated herein by reference in its entirety for all purposes. Background Art

[0004] This section is intended to introduce the reader to various aspects of the technology that may be related to the various aspects of the present disclosure described below. It is believed that this discussion helps to provide the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Therefore, it should be understood that these statements should be read in this light, and not as an admission of prior art.

[0005] HVAC&R systems are used in a variety of settings and for a variety of purposes. For example, an HVAC&R system may include a vapor compression refrigeration cycle (e.g., a refrigerant circuit having a condenser, an evaporator, a compressor, and / or an expansion device) configured to condition an environment. The vapor compression refrigeration cycle may include a compressor configured to direct a refrigerant through various components of the refrigerant circuit. In some cases, during operation of the vapor compression refrigeration cycle, the refrigerant pressure at various locations along the refrigerant circuit may fluctuate. Therefore, the compression ratio of the compressor (e.g., the ratio between a low or suction pressure and a high or discharge pressure) can be adjusted to maintain an operating parameter of the vapor compression refrigeration cycle at a target level. In order to adjust the compression ratio of the compressor, the speed of one or more rotors of the compressor can be adjusted via a motor or other suitable drive. In addition, the volume ratio of the compressor can be adjusted based on the compression ratio to maintain the performance of the compressor.

[0006] Existing compressors may be configured to adjust the volume ratio in response to a given compression ratio via stepwise control of the piston between one or more positions. Additionally or alternatively, a proportional valve may be used to supply fluid to the piston chamber to adjust the position of the piston. Unfortunately, prior art techniques for controlling the volume ratio of a compressor may be limited by the limited number of positions of the piston and / or may increase costs by including additional components such as a proportional valve and corresponding control means. Summary of the invention

[0007] In an embodiment of the present disclosure, a volume ratio control system for a compressor includes: a chamber formed in a shell of the compressor, wherein the chamber is fluidically connected to a high-pressure side of the compressor; a piston disposed in the chamber, wherein the piston includes a cavity fluidically connected to a low-pressure side of the compressor; and a biasing device disposed in the chamber and configured to enable the piston to move in response to a pressure difference between the low-pressure side of the compressor and the high-pressure side of the compressor dropping below a threshold.

[0008] In another embodiment of the present disclosure, a heating, ventilation, air conditioning and / or refrigeration (HVAC&R) system includes: a compressor configured to circulate a refrigerant through a refrigerant circuit; and a volume ratio control system configured to adjust the volume ratio of the compressor. The volume ratio control system includes: a chamber formed in a housing of the compressor and in fluid communication with a high-pressure side of the compressor; a piston disposed in the chamber, wherein the piston includes a cavity in fluid communication with a low-pressure side of the compressor; and a biasing device disposed in the cavity, wherein the biasing device is configured to enable the piston to move in response to a pressure difference between the low-pressure side of the compressor and the high-pressure side of the compressor falling below a threshold.

[0009] In another embodiment of the present disclosure, a volume ratio control system for a compressor includes: a chamber formed in a housing of the compressor, wherein the chamber includes a first portion in fluid communication with a high pressure side of the compressor and a second portion in fluid communication with a low pressure side of the compressor; and a rod extending through an opening of the housing to separate the first portion and the second portion of the chamber, wherein the rod is fixed in the chamber relative to an axis defining the length of the chamber. The volume ratio control system also includes: a piston disposed in the first portion of the chamber, wherein the piston includes a cavity in fluid communication with the second portion of the chamber, and wherein the rod is configured to be at least partially disposed in the cavity of the piston; and a biasing device disposed in the cavity between the rod and an inner surface of the piston, wherein the biasing device is configured to enable the piston to move in response to a pressure differential between the low pressure side of the compressor and the high pressure side of the compressor falling below a threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a perspective view of a building in which an embodiment of a heating, ventilation, air conditioning and / or refrigeration (HVAC&R) system may be used in a commercial environment according to one aspect of the present disclosure;

[0011] Figure 2is a perspective view of an embodiment of a vapor compression system according to one aspect of the present disclosure;

[0012] Figure 3 A schematic diagram of an embodiment of a vapor compression system according to one aspect of the present disclosure;

[0013] Figure 4 is a schematic diagram of another embodiment of a vapor compression system according to one aspect of the present disclosure;

[0014] Figure 5 is a cross-sectional view of an embodiment of a compressor having a volume ratio control system that may be included in a vapor compression system according to one aspect of the present disclosure;

[0015] Figure 6 is a cross-sectional schematic diagram of an embodiment of a volume ratio control system for a compressor in a first position according to one aspect of the present disclosure; and

[0016] Figure 7 is a cross-sectional schematic diagram of an embodiment of a volume ratio control system for a compressor in a second position according to one aspect of the present disclosure. DETAILED DESCRIPTION

[0017] One or more specific embodiments of the present disclosure will be described below. These described embodiments are merely examples of the currently disclosed technology. In addition, in an effort to provide a concise description of these embodiments, all features of the actual implementation scheme may not be described in the specification. It should be understood that in the development of any such actual implementation scheme, as in any engineering technology or design project, numerous implementation scheme-specific decisions must be made to achieve the specific goals of the developer, such as complying with system-related and business-related constraints, which may vary depending on the implementation scheme. In addition, it should be understood that such development efforts may be complex and time-consuming, but are still routine tasks of design, assembly and manufacture for those of ordinary skill in the art who benefit from the present disclosure.

[0018] As discussed above, a vapor compression refrigeration cycle may include a compressor configured to circulate a refrigerant through a refrigerant circuit of a vapor compression refrigeration cycle. In some cases, various operating parameters of the refrigerant may fluctuate during the operation of the vapor compression refrigeration cycle. The compression ratio of the compressor may be adjusted to maintain and / or adjust the operating parameters of the refrigerant in the refrigerant circuit to a target level. The compression ratio of the compressor may be controlled via a motor that provides torque to one or more rotors of the compressor. Therefore, the operating speed of the motor is adjusted to control the compression ratio to achieve a target value. In addition, the volume ratio of the compressor may be adjusted based on the compression ratio to maintain the performance (e.g., efficiency) of the compressor during operation. In fact, in some cases, the amount of refrigerant drawn to the compressor may exceed the amount to achieve the target compression ratio. Therefore, the volume ratio may be adjusted by causing the refrigerant to bypass the compression portion of the compressor so as to reduce the volume ratio. Similarly, the amount of refrigerant drawn to the compressor may be less than the amount to achieve the target compression ratio. In this case, the volume ratio may be adjusted by preventing the refrigerant from bypassing the compression portion, thereby increasing the volume ratio of the compressor.

[0019] Existing compressors may use a piston that can be adjusted to a limited number of positions to control the volume ratio of the compressor. For example, the piston may be in fluid communication with the high pressure side of the compressor to enable the refrigerant to bypass the compression portion of the compressor based on the position of the piston. In addition, some existing compressors may include a proportional valve that directs the working fluid to the piston chamber to produce the movement of the piston, thereby providing control over the position of the piston. However, such existing systems may be limited in controlling the volume ratio and / or may increase the cost of the vapor compression refrigeration cycle.

[0020] Therefore, embodiments of the present disclosure relate to an improved volume ratio control system that can enhance the control of the volume ratio of the compressor without including relatively expensive components. For example, the volume ratio control system of the present disclosure may include a biasing device, such as a spring, to control the position of a piston disposed in a chamber of the compressor. The chamber and / or the piston may be fluidly connected to a low-pressure portion (e.g., suction side) of the compressor and a high-pressure portion (e.g., discharge side) of the compressor, thereby generating a pressure difference in the chamber and / or on the piston. Under some operating conditions, the pressure difference in the chamber and / or on the piston may exceed a threshold value, thereby causing the piston to move in a first direction to adjust the volume ratio of the compressor (e.g., increase the volume ratio of the compressor in response to an increase in the compression ratio). When the pressure difference drops below the threshold, the biasing device may cause the piston to move in a second direction opposite to the first direction to adjust the volume ratio of the compressor (e.g., reduce the volume ratio of the compressor in response to a decrease in the compression ratio). The piston may be configured to move in a second direction to expose an opening, allowing the refrigerant to bypass the compression portion of the compressor (e.g., at least a portion of the compression chamber), so that when the piston exposes or does not cover the opening, the volume ratio is reduced. Similarly, when the piston moves in a first direction to cover and / or block the opening, the volume ratio of the compressor can be increased, thereby reducing the amount of refrigerant that bypasses the compression portion. Therefore, the volume ratio control system of the present disclosure is a passive system that uses the pressure difference in the chamber and the biasing force applied to the piston by the biasing device to adjust the volume ratio of the compressor. In fact, the volume ratio control system can be infinitely variable, so that the piston can move to almost any position in the chamber, without being limited to a predetermined or separated position.

[0021] Turning now to the accompanying drawings, Figure 1 1 is a perspective view of an environmental embodiment of a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system 10 for use in a building 12 in a typical commercial environment. The HVAC&R system 10 may include a vapor compression system 14 that supplies a refrigerant liquid that may be used to cool the building 12. The HVAC&R system 10 may also include a boiler 16 for supplying heated liquid to heat the building 12, and an air distribution system that circulates air within the building 12. The air distribution system may also include return air ducts 18, supply air ducts 20, and / or air handlers 22. In some embodiments, the air handler 22 may include a heat exchanger connected to the boiler 16 and the vapor compression system 14 by conduits 24. Depending on the operating mode of the HVAC&R system 10, the heat exchanger in the air handler 22 may receive heated liquid from the boiler 16, or refrigerant liquid from the vapor compression system 14. The HVAC&R system 10 is shown with a separate air handler on each floor of the building 12, but in other embodiments, the HVAC&R system 10 may include air handlers 22 and / or other components that may be shared between floors.

[0022] Figure 2 and 3 An embodiment of a vapor compression system 14 is shown that may be used in the HVAC&R system 10. The vapor compression system 14 may circulate a refrigerant through a circuit starting at a compressor 32. The circuit may also include a condenser 34, an expansion valve or device 36, and a liquid cooler or evaporator 38. The vapor compression system 14 may also include a control panel 40 (e.g., a controller) having an analog-to-digital (A / D) converter 42, a microprocessor 44, a non-volatile memory 46, and / or an interface board 48.

[0023] In some embodiments, the vapor compression system 14 may use one or more of a variable speed drive (VSD) 52, a motor 50, a compressor 32, a condenser 34, an expansion valve or device 36, and / or an evaporator 38. The motor 50 may drive the compressor 32 and may be powered by the variable speed drive (VSD) 52. The VSD 52 receives alternating current (AC) power having a specific fixed pipeline voltage and a fixed pipeline frequency from an AC power source and provides power having a variable voltage and a variable frequency to the motor 50. In other embodiments, the motor 50 may be powered directly by an AC or direct current (DC) power source. The motor 50 may include any type of motor that may be powered by a VSD or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor.

[0024] The compressor 32 compresses the refrigerant vapor and delivers the vapor to the condenser 34 through a discharge passage. In some embodiments, the compressor 32 may be a screw compressor. The compressor 32 contains a fluid (e.g., oil) that lubricates the compressor components. The refrigerant vapor delivered to the condenser 34 by the compressor 32 may transfer heat to a cooling fluid (e.g., water or air) in the condenser 34. As a result of the heat transfer with the cooling fluid, the refrigerant vapor may condense into a refrigerant liquid in the condenser 34. The refrigerant liquid from the condenser 34 may flow through the expansion device 36 to the evaporator 38. In the Figure 3 In the illustrated embodiment of , the condenser 34 is water cooled and includes a tube bundle 54 connected to a cooling tower 56 that provides cooling fluid to the condenser 34 .

[0025] The refrigerant liquid delivered to the evaporator 38 may absorb heat from another cooling fluid, which may or may not be the same cooling fluid used in the condenser 34. The refrigerant liquid in the evaporator 38 may undergo a phase change from a refrigerant liquid to a refrigerant vapor. Figure 3As shown in the illustrated embodiment of , the evaporator 38 may include a tube bundle 58 having a supply flow line 60S and a return flow line 60R connected to a cooling load 62. The cooling fluid of the evaporator 38 (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) enters the evaporator 38 via the return flow line 60R and leaves the evaporator 38 via the supply flow line 60S. The evaporator 38 may reduce the temperature of the cooling fluid in the tube bundle 58 by heat transfer with the refrigerant. The tube bundle 58 in the evaporator 38 may include multiple tubes and / or multiple tube bundles. In any case, the refrigerant vapor leaves the evaporator 38 and returns to the compressor 32 through the suction line to complete the cycle.

[0026] Figure 4 is a schematic diagram of a vapor compression system 14 having an intermediate loop 64 coupled between the condenser 34 and the expansion device 36. The intermediate loop 64 may have an inlet line 68 that is directly fluidly connected to the condenser 34. In other embodiments, the inlet line 68 may be indirectly fluidly coupled to the condenser 34. Figure 4 As shown in the illustrated embodiment of , the inlet line 68 includes a first expansion device 66 located upstream of the intermediate vessel 70. In some embodiments, the intermediate vessel 70 can be a flash tank (e.g., a flash intercooler). In other embodiments, the intermediate vessel 70 can be configured as a heat exchanger or a "surface economizer". Figure 4 In the illustrated embodiment of the invention, the intermediate container 70 is used as a flash tank, and the first expansion device 66 is configured to reduce (e.g., expand) the pressure of the refrigerant liquid received from the condenser 34. During the expansion process, a portion of the liquid may evaporate, so the intermediate container 70 can be used to separate the vapor from the liquid received from the first expansion device 66. In addition, due to the pressure drop experienced by the refrigerant liquid when entering the intermediate container 70 (e.g., due to the rapid increase in volume experienced when entering the intermediate container 70), the intermediate container 70 can provide further expansion of the refrigerant liquid. The vapor in the intermediate container 70 can be drawn by the compressor 32 through the suction line 74 of the compressor 32. In other embodiments, the vapor in the intermediate container can be drawn to an intermediate stage (e.g., a non-suction stage) of the compressor 32. Due to the expansion occurring in the expansion device 66 and / or the intermediate container 70, the liquid collected in the intermediate container 70 can have a lower enthalpy than the refrigerant liquid leaving the condenser 34. Next, the liquid from the intermediate container 70 can flow through the second expansion device 36 in the pipeline 72 to the evaporator 38.

[0027] As discussed above, embodiments of the present disclosure relate to an improved volume ratio control system for a compressor (e.g., compressor 32). The volume ratio control system may include a piston and a rod (e.g., a fixed rod) disposed in a chamber of the compressor. The piston may be disposed in at least a portion of a chamber exposed to the high pressure side of the compressor. For example, the high pressure side may be the discharge side of the compressor, so that the outer surface of the piston is also exposed to the discharge side of the compressor (e.g., the discharge pressure of the compressor). In some embodiments, the outer surface of the piston may be additionally or alternatively exposed to the oil pressure of the compressor. In addition, the cavity of the piston may be in fluid communication with the low pressure side of the compressor. For example, the low pressure side may be the suction side of the compressor (e.g., the suction pressure of the compressor), thereby exposing the inner surface of the piston to the suction side of the compressor. Therefore, when the opposite pressures applied to the outer and inner surfaces of the piston change, a pressure differential force may be applied to the piston. The pressure differential force may at least partially control the position of the piston relative to the chamber and / or the rod. In addition, a biasing device, such as a spring, may be provided in the cavity between the piston and the rod. When the pressure differential force drops below a threshold, the biasing device may direct movement of the piston (e.g., relative to the rod). As used herein, the threshold of the pressure differential force may be a function of the biasing force of the biasing device and / or the position of the piston in the chamber (and / or relative to the rod). In practice, the threshold of the pressure differential force may vary based at least on the current length and / or current extension level of the biasing device. For example, the biasing force applied by the biasing device may vary as the biasing device extends and / or contracts from a natural or unbiased position (e.g., the biasing force increases as the biasing device moves further from a natural or unbiased position).

[0028] In any case, the volume ratio control system of the present disclosure is passive because the volume ratio control system adjusts the volume ratio of the compressor based on the pressure difference formed between the chamber and the piston cavity, and the pressure difference can represent the compression ratio of the compressor. In other words, in order to adjust the volume ratio of the compressor, additional mechanical components, such as valves, motors and / or other devices, may not be included. In addition, the volume ratio control system is generally infinitely variable because the position of the piston in the chamber is not limited to a stepwise or predetermined position. Therefore, the volume ratio control system can achieve accurate and / or precise volume ratio control of the compressor without including relatively expensive components that would increase the cost of the vapor compression system 14.

[0029] For example, Figure 5 is a cross-sectional view of an embodiment of a compressor 100 (e.g., compressor 32) having a volume ratio control system 102. Figure 5As shown in the illustrated embodiment of , the compressor 100 includes two volume ratio control systems 102. In other embodiments, depending on the size and / or capacity of the compressor 100, the compressor 100 may include a single volume ratio control system 102 or more than two volume ratio control systems 102. In any case, the compressor 100 may include a low-pressure side 104 (e.g., suction side, suction portion), which draws refrigerant from a component disposed along the refrigerant circuit of the vapor compression system 14 (e.g., from the evaporator 38); and a high-pressure side 106 (e.g., discharge side, discharge portion, oil pressure), which directs the high-pressure refrigerant to a component disposed along the refrigerant circuit (e.g., to the condenser 34). The compressor 100 includes a rotor 108, which is configured to rotate and compress the refrigerant received at the low-pressure side 104, thereby increasing the pressure of the refrigerant leaving the compressor 100 via a discharge orifice located on the high-pressure side 106. For example, the rotor 108 may be driven to rotate via a motor. When the rotor 108 rotates, the threads of the rotor 108 may reduce the volume of the refrigerant in the compression chamber 109 of the compressor 100 , thereby increasing the pressure of the refrigerant.

[0030] like Figure 5 As shown in the illustrated embodiment of , the compressor 100 includes openings 110 in the housing 112 of the compressor 100, which enable the refrigerant to bypass at least a portion 114 of the compression chamber 109 and direct the refrigerant to the high pressure side 106. In other words, the refrigerant flowing through the openings 110 can reduce the amount of refrigerant that is ultimately compressed by the rotor 108, thereby reducing the volume ratio of the compressor 100. In some embodiments, the openings 110 can be formed in a portion of the housing 112 associated with and / or including one of the rotors 108. For example, a first set of openings 110 can be formed in a portion of the housing 112 associated with and / or including one of the rotors 108 (e.g., a male rotor), and a second set of openings 110 can be formed in a portion of the housing 112 associated with and / or including another of the rotors 108 (e.g., a female rotor). As described above, the illustrated compressor 100 includes two volume ratio control systems 102. Each volume ratio control system 102 may be associated with one of the plurality of groups of openings 110 and may operate in a manner described below to shield and / or expose the corresponding group of openings 110. However, in other embodiments, the compressor 100 may include one volume ratio control system 102 associated with two groups of openings 110, such that the single volume ratio control system 102 operates to shield and / or expose the openings 110 associated with two rotors 108 (e.g., a male rotor and a female rotor).

[0031] The volume ratio control system 102 is configured to adjust the amount of refrigerant flowing through the opening 110 and bypassing at least a portion 114 of the compression chamber 109 within the compressor 100. For example, the volume ratio control system 102 includes a piston 116 (e.g., an annular piston) disposed within a chamber 118 formed in the shell 112. The chamber 118 can be in fluid communication with the opening 110 and can extend into a first portion 120 of the shell 112 near the low-pressure side 104. In addition, the chamber 118 can extend into a second portion 122 of the shell 112 near the high-pressure side 106. In any case, the piston 116 is configured to move within the chamber 118 to block and / or expose the opening 110, thereby controlling the amount of refrigerant bypassing the portion 114 of the compression chamber 109.

[0032] As described in further detail herein, movement of the piston 116 within the chamber 118 may be passively controlled by a biasing device 124 (e.g., a spring) and / or a pressure differential between a cavity 126 formed within the piston 116 (e.g., fluidly coupled to the low-pressure side 104 of the compressor 100 via an orifice, conduit, etc.) and at least a portion 128 of the chamber 118 (e.g., fluidly coupled to the high-pressure side 106 of the compressor 100 via a discharge line 135). In some embodiments, the volume ratio control system 102 includes a rod 129 (e.g., a stationary rod) disposed within the chamber 118 and within the cavity 126 of the piston 116. Figure 5 As shown in the illustrated embodiment of , the biasing device 124 can be disposed between the rod 129 and the piston 116 within the cavity 126. In addition, the rod 129 can include a passage 131 that fluidly couples an additional portion 133 of the chamber 118 (e.g., fluidly coupled to the low-pressure side 104 of the compressor 100) and the cavity 126. Therefore, in some embodiments, the pressure within the cavity 126 of the piston 129 can be substantially equal to the low pressure or suction pressure of the compressor 100 (e.g., within 10%, within 5%, or within 1% of the low pressure or suction pressure).

[0033] In any event, the biasing device 124 and the pressure differential between the cavity 126 and the portion 128 of the chamber 118 can cause the piston 116 to move within the chamber 118 and / or relative to the rod 129. For example, the cavity 126 can contain a relatively low pressure associated with the refrigerant entering the compressor 100 at the low pressure side 104, while the portion 128 of the chamber 118 can contain a relatively high pressure associated with the refrigerant leaving the compressor 100 at the high pressure side 106. When a threshold pressure differential (e.g., a variable pressure differential threshold) is reached and / or exceeded, the pressure differential between the cavity 126 and the portion 128 of the chamber 118 can guide the movement of the piston 116 within the chamber 118. For example, when the pressure differential is at and / or exceeds the threshold pressure differential, a force is exerted on the piston 116 to guide the piston 116 along a length 134 (e.g., see FIG. 1 ) that defines the chamber 118. Figure 6) moves in a first direction 130. When the piston 116 moves in the first direction 130, the piston 116 can block and / or cover one or more openings 110 to the chamber 118 (e.g., preventing the refrigerant from bypassing the rotor 108 and / or the portion 114 of the compression chamber 109). Therefore, as the compression ratio of the compressor 100 increases, the volume ratio control system 102 increases the volume ratio to maintain the performance (e.g., efficiency) of the compressor 100.

[0034] In addition, the biasing device 124 applies a force to the piston 116 that can guide the piston 116 to move along the axis 132 in a second direction 136 opposite to the first direction 130 when the pressure differential between the cavity 126 and the portion 128 drops below a pressure differential threshold (e.g., a variable pressure differential threshold). For example, the biasing device 124 can include target parameters that apply a target biasing force to the piston 116 at various positions within the chamber 118 to enable the piston 116 to move in the second direction 136 when the pressure differential between the cavity 126 and the portion 128 drops below the pressure differential threshold for a given position of the piston 116 within the chamber 118. Parameters of the biasing device 124 that may be selected or modified to achieve a desired biasing force or range of biasing forces may include the material of the biasing device 124 (e.g., metal, polymer), the coil diameter of the biasing device 124, the inner diameter of the biasing device 124, the outer diameter of the biasing device 124, the coil pitch of the biasing device 124, the number of coils of the biasing device 124, the spring rate of the biasing device 124, the free length of the biasing device 124, the block length of the biasing device 124, another suitable parameter of the biasing device 124, or any combination thereof. In any case, the pressure differential between the cavity 126 and the portion 128 and the target biasing force of the biasing device 124 may passively guide the movement of the piston 116 within the chamber 118 to adjust the volume ratio of the compressor 100.

[0035] Figure 6 1 is a schematic cross-sectional view of a portion of the compressor 100, illustrating the chamber 118 of the volume ratio control system 102. Figure 6As shown in the illustrated embodiment of , the piston 116 is disposed within the portion 128 of the chamber 118. In addition, the rod 129 extends between the additional portion 133 of the chamber 118 and the portion 128 of the chamber 118 via an opening 150 (e.g., an opening formed in the housing 112 between the portion 128 of the chamber 118 and the additional portion 133). The rod 129 can be secured within the opening 150 via a fastener 152 (e.g., a threaded fastener), which can prevent movement of the rod 129 relative to and / or within the chamber 118. However, in other embodiments, the rod 129 can be secured within the opening 150 and / or relative to the chamber 118 via other mechanisms or features. For example, the rod 129 and the opening 150 can each include threads configured to engage with each other to secure the rod 129 within the opening 150.

[0036] In addition, the rod 129 can form a seal between the additional portion 133 of the chamber 118 and the portion 128 of the chamber 118 to maintain a pressure differential substantially equal to the pressure differential between the low pressure side 104 and the high pressure side 106 of the compressor 100. In some embodiments, the rod 129 includes a passage 131 that enables fluid communication between the additional portion 133 of the chamber 118 and the cavity 126. Thus, the pressure within the cavity 126 can be substantially equal to the suction pressure of the compressor 100 (e.g., the additional portion 133 of the cavity 126 is exposed to the low pressure side 104 of the compressor 100). In addition, the portion 128 of the chamber 118 can be fluidly coupled to the high pressure side 106 of the compressor 100 via a discharge line 135, and / or the fluid coupling opening 110.

[0037] Thus, a first pressure (e.g., represented by arrow 156) may be applied to an inner surface 158 of the piston 116, wherein the first pressure indicates a low (e.g., suction) pressure of the compressor 100. A second pressure (e.g., represented by arrow 160) may be applied to an outer surface 162 of the piston 116, wherein the second pressure indicates a high (e.g., discharge, oil) pressure of the compressor 100. The first (e.g., low) pressure is less than the second (e.g., high) pressure, such that a pressure differential force (e.g., the difference between the first pressure and the second pressure) may be applied to the piston 116 in the first direction 130. Additionally, the biasing device 124 may apply a biasing force (e.g., represented by arrow 164) to the piston 116 in a second direction 136 that is opposite to the first direction 130. Thus, when the pressure differential force exceeds the biasing force, the piston 116 moves in the first direction 130 toward an end 166 of the portion 128 of the chamber 118 that is proximate to the opening 110. The piston 116 may cover and / or block one or more of the openings 110, such that the volumetric ratio of the compressor 100 is increased. Similarly, when the pressure differential force is less than the biasing force, the biasing device 124 enables the piston 116 to move in the second direction 136 away from the end 166 of the portion 128 of the chamber 118 proximate to the opening 110. Thus, one or more of the openings 110 may be exposed or uncovered, such that the refrigerant may bypass the portion 114 of the compression chamber 109 and reduce the volumetric ratio of the compressor 100.

[0038] As shown in the illustrated embodiment, the piston 116 includes a first section 168 and a second section 170, each of which is configured to move (e.g., move together) in the first direction 130 and the second direction 136 within the portion 128 of the chamber 118. For example, the first section 168 and the second section 170 can be a single piece forming the piston 116. The first section 168 can include a first radial thickness 172 that is greater than a second radial thickness 174 of the second section 170. In some embodiments, an outer diameter 176 of the piston 116 corresponds to a diameter 178 of the portion 128 of the chamber 118. For example, the overall diameter 176 can be slightly smaller than the diameter 178 to enable the piston 116 to move along the axis 132 within the portion 128 of the chamber 118.

[0039] like Figure 6As shown in the illustrated embodiment, the outer surface 162 of the first section 168 of the piston 116 is exposed to the interior of the portion 128 of the chamber 118, and therefore, is exposed to the refrigerant within the portion 128 of the chamber 118. In some embodiments, the outer surface 162 of the first section 168 of the piston 116 may be exposed to the oil pressure of the compressor 100. As described above, the refrigerant in the portion 128 may include a pressure substantially equal to the discharge pressure of the refrigerant leaving the compressor 100 (and / or the oil pressure of the compressor 100). In addition, the second section 170 of the piston 116 may include a second surface 182, which is also exposed to the interior of the portion 128 of the chamber 118, and therefore, is exposed to the refrigerant within the portion 128 of the chamber 118 (and / or the oil pressure of the compressor 100). Therefore, the outer surface 162 and the second surface 182 may be exposed to the refrigerant at substantially the same pressure. As Figure 6 As shown, the surface area of ​​the outer surface 162 is greater than the surface area of ​​the second surface 182, so an increase in discharge (or oil) pressure may cause movement in the first direction 130 via the pressure applied to the outer surface 162. In addition, the inner surface 158 of the first section 168 of the piston 118 is exposed to the refrigerant, which contains a pressure substantially equal to the refrigerant suction pressure entering the compressor 100. Therefore, as the pressure differential between the cavity 126 and the portion 128 of the chamber 118 increases, the piston 116 is directed in the first direction 130 via the pressure differential force.

[0040] In some embodiments, a biasing device 124 (e.g., a spring) can be disposed within the cavity 126 of the piston 116 between the rod 129 and the inner surface 186 of the piston 116. The rod 129 can be substantially fixed within the chamber 118 such that the piston 116 is configured to move along at least a portion of the length 188 of the rod 129. For example, the rod 129 can be coupled to the opening 150 of the chamber 118, thereby separating the portion 128 from the additional portion 133. In some embodiments, the rod 129 can be coupled to the opening 150 via threads as described above, via bolts or other fasteners, via welding, or other suitable coupling techniques that enable the rod 129 to maintain a position relative to the chamber 118. In addition, the biasing device 124 can be coupled to the end 190 of the rod 129, such as welded to the end 190, fastened to the end 190 via fasteners (e.g., screws, bolts, or other suitable fasteners), or coupled to the end 190 via another suitable technique. In any case, the biasing device 124 applies a force on the end 192 (e.g., the inner surface 158) of the piston 116 in the second direction 136 or toward the natural position (e.g., the unbiased position) of the biasing device 124. When the piston 116 is toward the first direction 130, the biasing device 124 can be compressed against the end 188 of the rod 129 and exert a greater force on the piston 116. In some embodiments, the rod 129 can also serve as a guide for the biasing device 124 as it is compressed and decompressed due to changes in the pressure differential. For example, the biasing device 124 can be configured to move along the outer surface 194 of the rod 129 as the piston 116 moves within the portion 128 of the chamber 118. In any case, the pressure differential threshold that drives the piston 116 to move can vary based on the amount of compression of the biasing device 124 and / or the current length of the biasing device 124 compared to the natural or unbiased length of the biasing device 124.

[0041] As the pressure differential between cavity 126 and portion 128 of chamber 118 decreases, biasing device 124 may direct piston 116 to move in second direction 136 by exerting a force in second direction 136 on piston 116. For example, Figure 6 The piston 116 is shown in a substantially open position (eg, when the volume ratio of the compressor 100 is reduced), and Figure 7 The piston 116 is shown in a substantially closed position (e.g., when the volume ratio of the compressor 100 is increased). Figure 7 In the illustrated embodiment shown in FIG. 2 , the biasing device 124 is in the compressed position 210 and exerts a force on the piston 116 in the second direction 136 .

[0042] As discussed above, the amount of force applied by the biasing device 124 to the piston 116 may be based on the position of the piston 116 within the portion 128 of the chamber 118 relative to the shaft 132, the amount of extension and / or compression of the biasing device 124, parameters of the biasing device 124 itself, other suitable parameters, or any combination thereof. For example, parameters of the biasing device 124 that may contribute to the magnitude of the biasing force applied to the piston 116 may include the material of the biasing device 124 (e.g., metal, polymer), the coil diameter of the biasing device 124, the inner diameter of the biasing device 124, the outer diameter of the biasing device 124, the pitch of the biasing device 124, the number of coils of the biasing device 124, the spring rate of the biasing device 124, the free length of the biasing device 124, the block length of the biasing device 124, another suitable parameter of the biasing device 124, or any combination thereof.

[0043] In any case, the pressure differential within the cavity 126 of the piston 116 and the portion 128 of the chamber 118 that applies a force to the outer surface 162 of the piston 116 in the first direction 130 and the biasing force applied by the biasing device 124 to the piston 116 in the second direction 136 control the movement and position of the piston 116 in the chamber 118. The pressure differential threshold for guiding the movement of the piston 116 in the first direction 130 can be varied based on the position of the piston 116 and / or the extension and / or compression level of the biasing device 124. Therefore, when the pressure differential and the opposing force applied by the biasing device 124 are substantially equal, the piston 116 can be positioned at almost any position (e.g., fixed) within the portion 128 of the chamber 118 relative to the shaft 132. Therefore, the volume ratio control system 102 of the present disclosure can achieve infinite or substantially infinite variable control of the volume ratio of the compressor 100.

[0044] As described above, embodiments of the present disclosure can provide one or more technical effects for controlling the volume ratio of a compressor. For example, embodiments of the present disclosure are directed to an improved volume ratio control system that can passively operate and achieve infinitely variable control of the volume ratio. The volume ratio control system may include a piston disposed in at least a portion of a chamber of the compressor, wherein at least a portion of the fluid is coupled to the high pressure side (e.g., discharge side or oil pressure) of the compressor. The piston may include a cavity that is fluidly coupled to the low pressure side (e.g., suction side) of the compressor. In addition, a rod and a biasing device may be disposed in the cavity of the piston. When the compressor is operating, a pressure difference may be formed between the cavity and the chamber of the piston. When the pressure difference exceeds a threshold value, the pressure difference may apply a force to the piston in a first direction so that the piston blocks or covers an opening, enabling the refrigerant to bypass at least a portion of the compression chamber of the compressor. Therefore, the volume ratio of the compressor increases. When the pressure difference drops below a threshold value, the biasing device may apply a force to the piston in a second direction opposite to the first direction to unlock or expose the opening. Therefore, the pressure ratio of the compressor decreases. In any case, the volume ratio control system can passively control the volume ratio of the compressor, thereby reducing costs and enhancing the control of the compressor volume ratio. The technical effects and technical problems in the specification are only examples and not limitations. It should be noted that the embodiments described in this specification may have other technical effects and may solve other technical problems.

[0045] Although only certain features and embodiments of the present invention are illustrated and described, those skilled in the art may conceive of many modifications and changes (e.g., changes in the size, dimensions, structure, shape and proportion of each element, parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without substantially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be changed or reordered according to alternative embodiments. Therefore, it should be understood that the appended claims are intended to cover all such modifications and changes as belong to the true spirit of the present invention. In addition, in order to provide a concise description of an exemplary embodiment, all features of the actual implementation may not be described (e.g., those features that are not related to the currently expected best mode of implementing the present invention, or those features that are not related to the invention claimed for protection). It should be understood that in the development of such actual implementations, as in any engineering technology or design project, numerous implementation-specific decisions may be made. Such development work may be complex and time-consuming, but for ordinary technicians who benefit from this disclosure, it is still a routine work of design, manufacture and processing without excessive experiments.

[0046] The technology presented and claimed herein is cited and applied to material objects and specific examples of a practical nature that demonstrably improve the art and are therefore not abstract, intangible, or purely theoretical. In addition, if any claim appended to the end of this specification contains one or more elements designated as "means for [performing] [a function] ..." or "steps for [performing] [a function] ...", it is intended that these elements be interpreted in accordance with 35 U.S.C. 112(f). However, for any claim containing elements designated in any other manner, these elements should not be interpreted in accordance with 35 U.S.C. 112(f).

Claims

1. A volume ratio control system for a compressor, comprising: a housing for the compressor, wherein the housing includes a chamber formed therein, and a portion of the chamber is in fluid communication with a discharge side of the compressor; as well as A piston is disposed in the chamber, wherein the piston includes a cavity connected to the suction side fluid of the compressor, wherein the portion of the chamber and the cavity are fluidly separated from each other, and the volume ratio control system is configured to passively adjust the position of the piston in the chamber based on a pressure difference between the portion of the chamber and the cavity of the piston.

2. A volumetric ratio control system according to claim 1, wherein the housing includes a plurality of openings formed therein, the plurality of openings being fluidly coupled to the chamber at the ends of the chamber, and the plurality of openings being configured to enable refrigerant to flow through the plurality of openings to bypass at least a portion of the compression chamber of the housing and flow toward the discharge side of the compressor.

3. A volumetric ratio control system according to claim 2, wherein the piston is configured to translate within the chamber in a direction toward the end of the chamber in response to the pressure differential meeting or exceeding a threshold pressure differential so as to overlap with one or more of the plurality of openings and block the refrigerant from flowing into the chamber through the one or more openings.

4. The volume ratio control system according to claim 2 includes a biasing device disposed in the cavity, wherein the biasing device is configured to apply a biasing force on the piston, and the biasing device is configured to translate within the chamber in a direction away from the end of the chamber in response to the pressure differential dropping below the biasing force.

5. The volume ratio control system according to claim 1 includes a discharge line extending through the housing to the chamber, wherein an outer surface fluid of the piston is exposed to the discharge line, and an inner surface fluid of the piston opposite to the outer surface is exposed to the cavity. 6 . The volume ratio control system of claim 5 , wherein the discharge line is configured to be fluidically exposed to oil pressure of the compressor.

7. The volume ratio control system according to claim 1, comprising: a rod extending into the chamber and into the cavity; as well as A biasing device is disposed about the rod and within the cavity.

8. The volume ratio control system of claim 7, wherein the rod is secured in the chamber via a threaded connection.

9. The volume ratio control system of claim 7, wherein the portion is a first portion, the chamber includes a second portion fluidly coupled to the suction side of the compressor, and the rod extends through an opening formed in the housing between the first portion of the chamber and the second portion of the chamber.

10. The volume ratio control system of claim 9, wherein the rod includes a passage fluidly coupling the second portion of the chamber and the cavity of the piston.

11. The volume ratio control system according to claim 7, wherein a first end of the biasing device is fixed to the rod, and a second end of the biasing device opposite to the first end is configured to apply a biasing force on an inner surface of the piston.

12. A compressor for heating, ventilation, air conditioning and / or refrigeration (HVAC&R), comprising: a housing including a compression chamber; a rotor disposed in the housing and configured to compress the refrigerant in the compression chamber; as well as A volume ratio control system configured to adjust the volume ratio of the compressor, wherein the volume ratio control system comprises: a chamber formed in the housing and including a first portion in fluid communication with a high pressure side of the compressor and a second portion in fluid communication with a low pressure side of the compressor; as well as a piston disposed within the chamber, wherein the piston includes a cavity formed therein, an inner surface of the piston defining the cavity being in fluid communication with the low-pressure side of the compressor, and an outer surface of the piston being in fluid communication with the high-pressure side of the compressor, The housing includes a plurality of openings formed therein, the plurality of openings being in fluid communication with the compression chamber and the chamber, and the volume ratio control system is configured to passively adjust a position of the piston within the chamber to adjust the volume ratio of the compressor.

13. The compressor of claim 12, wherein the volume ratio control system is configured to passively adjust the position of the piston within the chamber in response to changes in a pressure differential between the low pressure side of the compressor and the high pressure side of the compressor.

14. The compressor of claim 13, said piston being configured to translate within said chamber to adjust a first number of said plurality of openings to be obscured by said piston and a second number of said plurality of openings to be exposed to said piston.

15. The compressor according to claim 13, wherein the volume ratio control system includes a biasing device, which is arranged in the cavity of the piston, and wherein the biasing device is configured to adjust the position of the piston in the chamber in response to the pressure difference dropping below a threshold value, wherein the threshold value is a variable threshold value.

16. The compressor according to claim 12, wherein the volume ratio control system includes a rod fixed to the housing, the rod extending from the first portion of the chamber to the second portion of the chamber, the rod being disposed in the cavity, and the volume ratio control system includes a biasing device, the biasing device being disposed around the rod and the biasing device being fixed to the rod.

17. The compressor of claim 16, wherein said rod includes a channel formed therein, said channel fluidly coupling said second portion of said chamber and said cavity.

18. The compressor according to claim 12, wherein the outer surface of the piston includes a first outer surface and a second outer surface, the first outer surface is arranged at a first end of the piston, the second outer surface is arranged at a second end of the piston opposite to the first end, the second outer surface faces the end of the first part of the chamber, and the plurality of openings are formed in the housing at the end of the first part of the chamber.

19. The compressor of claim 18, wherein the housing includes a discharge line formed therein, and the discharge line is configured to fluidly couple the high pressure side of the compressor and the first portion of the chamber at the first end of the piston.

20. A volume ratio control system for a compressor, comprising: a housing for the compressor, wherein the housing includes a chamber formed therein, the chamber including a first portion in fluid communication with a discharge side of the compressor and a second portion in fluid communication with a suction side of the compressor, the housing including a plurality of openings formed therein, the plurality of openings configured to fluidly couple the first portion of the chamber to a compression chamber defined by the housing; a piston disposed within the first portion of the chamber, wherein the piston includes a cavity; a rod coupled to the housing, wherein the rod extends into the second portion of the chamber and into the cavity, wherein the rod defines a passage fluidly coupling the second portion of the chamber and the cavity; as well as A biasing device is disposed within the cavity and disposed about the rod, wherein the biasing device is configured to passively adjust the position of the piston within the chamber based on a pressure differential between the suction side of the compressor and the discharge side of the compressor to block or expose at least a subset of the plurality of openings, thereby adjusting a volumetric ratio of the compressor.

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