Pump for HVACR system

Abstract

The present disclosure discloses a heat exchanger for heating, ventilation, air conditioning and refrigeration (HVACamp; the invention relates to a pump (206) for a system (10, R) including a pump body (302) defining a compression chamber (316). The HVACamp; the R system (10) also includes a piston housing (311) coupled to the pump body (302). The piston housing (311) comprises a piston cavity (328). The pump (206) includes a piston (306) disposed within the piston housing (311). The piston (306) includes a plunger section (318) configured to reciprocate between the compression chamber (316) and the piston cavity (328). In addition, the piston (306) includes a head section (332) configured to reciprocate within the piston cavity (328). Further, the pump (206) includes a solenoid coil (312) configured to induce a magnetic force on the piston (306). Further, the pump (206) includes a controller (314) configured to control a flow of electrical current through the solenoid coil (312) to control reciprocating movement of the piston (306) within the piston cavity (328).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 541,201, filed on September 28, 2023, entitled “PUMP FOR HVAC&R SYSTEM,” and U.S. Provisional Application No. 63 / 443,921, filed on February 7, 2023, entitled “BEARING SYSTEM FOR HVAC&R SYSTEM,” each of which is hereby incorporated by reference in its entirety for all purposes. Background Art

[0002] This section is intended to introduce the reader to various aspects of technology that may be related to the various aspects of the present disclosure described below. It is believed that this discussion will help 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 admissions of prior art.

[0003] Chiller systems, or vapor compression systems, utilize a working fluid (e.g., a refrigerant) that changes phase between vapor, liquid, and combinations thereof in response to exposure to varying temperatures and pressures within the chiller system's components. Chiller systems can place the working fluid in heat exchange with a conditioning fluid (e.g., water) and deliver the conditioning fluid to the conditioning equipment and / or conditioned environment served by the chiller system. In such applications, the conditioning fluid can be directed through downstream equipment, such as an air handler, to condition other fluids, such as the air within a building. Chiller systems may include a compressor configured to pressurize the working fluid and circulate it through the chiller system's working fluid circuit. In some applications, the compressor's shaft may be rotated by a motor to drive the compressor's impeller, thereby pressurizing the working fluid. Traditionally, compressors include bearings configured to facilitate shaft rotation. Unfortunately, existing bearings used with compressors can be complex, expensive, and / or may result in inefficient chiller system operation. Summary of the Invention

[0004] The following describes an overview of certain embodiments disclosed herein. It should be understood that these aspects are presented merely to provide the reader with a brief overview of these specific embodiments, and these aspects are not intended to limit the scope of the present disclosure. In fact, the present disclosure may encompass various aspects that may not be described below.

[0005] In one embodiment, a pump for a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a pump body defining a compression chamber. The HVAC&R system also includes a piston housing coupled to the pump body. The piston housing includes a piston cavity. The pump further includes a piston disposed within the piston housing. The piston includes a plunger section configured to reciprocate between the compression chamber and the piston cavity. Additionally, the piston includes a head section configured to reciprocate within the piston cavity. Furthermore, the pump includes a solenoid coil configured to induce a magnetic force on the piston. Further, the pump includes a controller configured to control the flow of current through the solenoid coil to control the reciprocating motion of the piston within the piston cavity.

[0006] In another embodiment, a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system includes a pump configured to pump fluid along a circuit of the HVAC&R system. The pump includes a piston configured to reciprocate within a piston chamber of a piston housing. Additionally, the pump includes a block stop disposed at an end of the piston chamber. The block stop includes an internal switch configured to detect contact between the block stop and the piston. The HVAC&R system also includes a controller configured to control a stroke velocity of the piston based on a signal received from the internal switch.

[0007] In another embodiment, a method of operating a pump includes energizing a solenoid coil to cause a piston to translate in a first direction within a piston cavity. The method also includes detecting a first contact between the piston and a first stop within the piston cavity. Further, the method includes energizing the solenoid coil to cause the piston to translate in a second direction within the piston cavity that is opposite to the first direction. Additionally, the method includes detecting a second contact between the piston and a second stop within the piston cavity. Furthermore, the method includes determining a time interval between the first contact and the second contact. The method further includes adjusting energization of the solenoid coil based on a difference between the time interval and a previous time interval. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various aspects of the present disclosure may be better understood after reading the following detailed description and referring to the accompanying drawings, in which: Figure 1 is a perspective view of an embodiment of a building that may utilize a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system in a commercial environment according to an aspect of the present disclosure; Figure 2 is a perspective view of an embodiment of a vapor compression system according to one aspect of the present disclosure; Figure 3 is a schematic diagram of an embodiment of a vapor compression system according to an aspect of the present disclosure; Figure 4is a schematic diagram of an embodiment of a vapor compression system according to an aspect of the present disclosure; Figure 5 is a cross-sectional side view of an embodiment of a compressor of a vapor compression system according to an aspect of the present disclosure, illustrating a bearing system of the compressor; Figure 6 is a schematic diagram of an embodiment of a vapor compression system including a bearing system for a compressor according to an aspect of the present disclosure; Figure 7 is a cross-sectional side view of an embodiment of a pump for a fluid supply system for a bearing system according to an aspect of the present disclosure; Figure 8 is a schematic cross-sectional side view of an embodiment of a portion of a pump of a fluid supply system of a bearing system according to an aspect of the present disclosure; Figure 9 is a schematic cross-sectional side view of an embodiment of a portion of a pump of a fluid supply system for a bearing system according to an aspect of the present disclosure; and Figure 10 is a flow chart of an embodiment of a method of operating a pump of a fluid supply system for a bearing system according to an aspect of the present disclosure. DETAILED DESCRIPTION

[0009] One or more specific embodiments will be described below. In order to provide a concise description of these embodiments, not all features of the actual implementation are described in the specification. It should be understood that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as consistency with system-related constraints and enterprise-related constraints, which may vary from one implementation to another. Moreover, it should be understood that such development work may be complex and time-consuming, but is a routine task of design, manufacturing, and production for those of ordinary skill having the benefit of this disclosure.

[0010] When introducing elements of various embodiments of the present disclosure, the articles "a," "an," and "the" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. Furthermore, it should be understood that references to "one embodiment" or "an embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that further incorporate the recited features.

[0011] As used herein, the terms "approximately," "substantially," and "substantially" are intended to convey that the value of the property being described may be within a relatively small range of that property value, as understood by one skilled in the art. For example, when a property value is described as being "approximately" equal to (or, for example, "substantially similar to") a given value, this is intended to mean that the property value may be within + / - 5%, + / - 4%, + / - 3%, + / - 2%, + / - 1%, or even closer to the given value. Similarly, when a given feature is described as being "substantially parallel" to another feature, "substantially perpendicular" to another feature, etc., this is intended to mean that the given feature has the described property within + / - 5%, + / - 4%, + / - 3%, + / - 2%, + / - 1%, or even closer, such as being parallel to another feature, being perpendicular to another feature, etc. Furthermore, it should be understood that mathematical terms such as "flat," "slope," "perpendicular," "parallel," and the like are intended to encompass characteristics of surfaces or elements as understood by one of ordinary skill in the relevant art and should not be interpreted as strictly as would be understood in the mathematical arts. For example, a "flat" surface is intended to encompass a surface that is machined, molded, or otherwise formed to be generally flat or smooth (within relevant tolerances) using techniques and tools available to one of ordinary skill in the art. Similarly, a surface having a "slope" is intended to encompass a surface that is machined, molded, or otherwise formed to be oriented at an angle (e.g., tilted) relative to a reference point using techniques and tools available to one of ordinary skill in the art.

[0012] Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system (e.g., a chiller) that includes a vapor compression system (e.g., a vapor compression circuit, a working fluid circuit) with a compressor. During operation, the compressor pressurizes a working fluid within the vapor compression system and directs the working fluid to a condenser (e.g., a first heat exchanger), which cools and condenses the working fluid. The condensed working fluid may be directed to an expansion device, which may reduce the pressure of the working fluid, thereby further cooling the working fluid. From the expansion device, the cooled working fluid may be directed to an evaporator (e.g., a second heat exchanger), where it is brought into heat exchange with a conditioning fluid to cool the conditioning fluid. The conditioning fluid may circulate between the evaporator and a structure, such as a building, where it is used to cool an air flow delivered to a conditioned space within the structure. In some embodiments, an air handling unit (AHU) of the HVAC&R system may receive the conditioning fluid from the chiller and use it to cool the air flow delivered to the conditioned space. The conditioning fluid may then be returned to the evaporator for further cooling.

[0013] In some embodiments, a compressor may include a bearing system comprising bearings (e.g., hydrostatic bearings, porous bearings) that utilize pressurized fluid to support and lubricate the compressor's rotating shaft. According to the present technology, the bearings can be configured to receive pressurized fluid (e.g., in liquid phase) and discharge the pressurized fluid (e.g., in vapor phase) toward the rotating shaft, thereby enabling the levitation and rotation of the rotating body. For example, the bearing system may include a lubricant circuit extending from the working fluid circuit of the vapor compression system, directing a portion of the working fluid from the working fluid circuit to the compressor's bearings. In other words, a portion of the working fluid (e.g., refrigerant) in the lubricant circuit can be used as a lubricating fluid. The lubricant circuit may include a pump configured to pump pressurized fluid (e.g., lubricating fluid) toward the compressor's bearings. In this way, the working fluid, configured to exchange heat with the conditioning fluid as part of the working fluid circuit, can also be utilized in conjunction with the bearings to support the compressor's shaft. The pump may be a linear piston pump configured to apply pressure to the working fluid through the reciprocating motion of a piston. Unfortunately, existing pumps can create localized low-pressure areas, which can lead to cavitation of the working fluid within the pump. This cavitation can introduce unnecessary inefficiencies, wear, and / or degradation to the pump. Cavitation is particularly concerning during no-load operation of the pump. In some cases, the pump may operate without a flow of working fluid through it (e.g., due to a closed valve and / or other blockage in the lubricant circuit). Without working fluid flowing through the pump (e.g., a no-load condition), the pressurization of a constant mass of working fluid within the pump can increase the temperature of the working fluid, leading to cavitation during the return stroke of the piston. Furthermore, the increase in temperature can cause unnecessary wear and / or degradation of pump components.

[0014] Therefore, the present embodiments relate to an improved pump configured to pump a working fluid to a bearing of a compressor, including systems and methods for operating the pump. Specifically, the pump is configured to operate continuously through various operating conditions (including no-load) while reducing cavitation of the working fluid. The pump includes a piston that is drivable (e.g., in a reciprocating motion) by a solenoid coil controlled by a pump controller. The pump controller can control the current supplied to the solenoid coil to control the direction and speed of the piston, such as based on a current profile. Furthermore, the pump controller can adjust the current profile to reduce the speed of the piston's return stroke in response to detection of an indication of cavitation and / or potential cavitation.

[0015] To this end, the pump may include a forward block stop (e.g., a first block stop, a travel stop, or a damping stop) and a return block stop (e.g., a second block stop, a travel stop, or a damping stop), each positioned at a respective end of a piston chamber of the pump, within which the piston is disposed. Each block stop is configured to mechanically stop the piston upon impact at the respective end of the piston chamber (e.g., top dead center or bottom dead center). Each block stop may also include an internal switching mechanism configured to send a signal to the pump controller indicating contact between the block stop and the piston. Based on the time intervals detected between receipt of signals from the block stops, the pump controller may determine the speed and / or duration (e.g., duration) of the piston's compression stroke. Based on a determination that the speed and / or duration of the compression stroke appear and / or are abnormal (e.g., slower than a previous compression stroke), the pump controller may determine that cavitation may have occurred during the piston's return stroke. In response to determining that the speed of the compression stroke is slower than the previous compression stroke by a threshold amount, and / or the time period of the compression stroke is greater than the time period of the previous compression stroke, the pump controller may adjust the current profile to reduce the speed of the piston during the return stroke and / or increase the time period of the return stroke. In this way, the formation of localized low-pressure areas in the wake of the piston during the return stroke may be reduced and / or mitigated. Consequently, cavitation may be reduced. Additionally, the pump may include a non-magnetic heat sink coupled to the piston to facilitate cooling of the pump during operation. Thus, the pump is configured to operate under a variety of operating conditions while resisting the deleterious effects of no-load experienced by conventional pumps.

[0016] Turning now to the accompanying drawings, Figure 1 is a perspective view of an 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 may include a vapor compression system 14 for supplying a chilled liquid to cool the building 12 and a boiler 16 for supplying a warm liquid to heat the building 12. The vapor compression system 14 (also referred to herein as a chiller) may circulate a working fluid (e.g., a refrigerant) that is cooled by a cooling fluid (e.g., a liquid such as water) in a condenser of the vapor compression system 14 and heated by a conditioning fluid (e.g., a liquid such as water) in an evaporator of the vapor compression system 14. The cooling fluid may be provided by a cooling tower that cools the cooling fluid via, for example, ambient air. The conditioning fluid, cooled by the working fluid as described above, may be used to cool the air flow provided to the conditioned spaces of the building 12.

[0017] The HVAC&R system 10 may also include an air distribution system that circulates air through the building 12. The air distribution system may also include air return ducting 18, air supply ducting 20, and / or air handlers 22. In some embodiments, the air handler 22 may include a heat exchanger that is connected to the boiler 16 and the vapor compression system 14 via ducting 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 a conditioning fluid (e.g., cooled liquid such as water) from the vapor compression system 14. The HVAC&R system 10 is shown as having 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. Figure 2 and Figure 3 An embodiment of a vapor compression system 14 or chiller that can be used in an HVAC&R system 10 is shown. The vapor compression system 14 can circulate a working fluid through a circuit (e.g., a working fluid circuit) that begins with a compressor 32 (such as a centrifugal compressor). The circuit can also include a condenser 34, an expansion valve or device 36, and an evaporator 38. The vapor compression system 14 can further include a control panel 40 having an analog-to-digital (A / D) converter 42, a microprocessor 44, nonvolatile memory 46, and / or an interface board 48.

[0018] Some examples of fluids that can be used as working fluids in vapor compression system 14 include: hydrofluorocarbon (HFC)-based refrigerants, such as R-410A, R-407, R-134a, hydrofluoroolefins (HFOs); "natural" refrigerants, such as ammonia (NH3), R-717, carbon dioxide (CO2), R-744; or hydrocarbon-based refrigerants, water vapor, or any other suitable working fluid. Other possible working fluids include R-123, R-514A, R-1130yd, R-1233zd, R-134a, R-1142ze, R-1142yf, R-1311, R-32, and R-410A. In some embodiments, vapor compression system 14 can be configured to efficiently utilize a working fluid having a normal boiling point of approximately 19 degrees Celsius (66 degrees Fahrenheit) at one atmosphere of pressure, also known as a low-pressure refrigerant, as opposed to a medium-pressure working fluid such as R-134a. As used herein, "normal boiling point" may refer to a boiling point temperature measured at one atmosphere of pressure.

[0019] In some embodiments, the vapor compression system 14 may utilize one or more of a variable speed drive (VSD) 52, a motor 50, the compressor 32, the condenser 34, the expansion valve or device 36, and / or the evaporator 38. The motor 50 may drive the compressor 32 during a normal operating mode and may be powered by the variable speed drive (VSD) 52. The VSD 52 receives alternating current (AC) power during a normal operating mode, wherein the AC power comprises a specific fixed line voltage and a fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the motor 50. In other embodiments, the motor 50 may be powered directly from an AC or direct current (DC) power source. The motor 50 may include any type of motor that can 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.

[0020] The compressor 32 compresses the working fluid vapor and delivers the vapor to the condenser 34 through the exhaust passage. In some embodiments, the compressor 32 may be a centrifugal compressor. The working fluid vapor delivered to the condenser 34 by the compressor 32 can transfer heat to the cooling fluid (e.g., water or air) in the condenser 34. Due to the heat transfer with the cooling fluid, the working fluid vapor can be condensed into working fluid liquid in the condenser 34. The liquid working fluid from the condenser 34 can flow through the expansion device 36 to the evaporator 38. Figure 3 In the illustrated embodiment, the condenser 34 is water-cooled and includes a tube bundle 54 connected to a cooling tower 56 that supplies cooling fluid to the condenser 34 .

[0021] The liquid working fluid delivered to the evaporator 38 may absorb heat from the conditioning fluid, which is then directed to the load 62 (eg, Figure 1 For example, the conditioning fluid may be cooled by the working fluid in the evaporator 38 and may then be cooled in the Figure 1 The liquid working fluid in the evaporator 38 may undergo a phase change from liquid working fluid to working fluid vapor. Figure 3In the illustrated embodiment, the evaporator 38 may include a tube bundle 58 having a supply line 60S and a return line 60R connected to a cooling load 62. The conditioning fluid (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) for the evaporator 38 enters the evaporator 38 via the return line 60R and exits the evaporator 38 via the supply line 60S. The evaporator 38 may reduce the temperature of the conditioning fluid in the tube bundle 58 through heat transfer with the working fluid. The tube bundle 58 in the evaporator 38 may include multiple tubes and / or multiple tube bundles. In any case, the vapor working fluid exits the evaporator 38 and returns to the compressor 32 via the suction line to complete the cycle.

[0022] Figure 4 is a schematic diagram of an embodiment of a vapor compression system 14 having an intermediate loop 64 incorporated between the condenser 34 and the expansion device 36. The intermediate loop 64 may have an inlet line 68 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 In the illustrated embodiment, the inlet line 68 includes a first expansion device 66 positioned upstream of an intermediate vessel 70. In some embodiments, the intermediate vessel 70 may be a flash tank (e.g., a flash intercooler). In other embodiments, the intermediate vessel 70 may be configured as a "heat exchanger" or a "surface economizer." Figure 4 In the illustrated embodiment, the intermediate vessel 70 serves as a flash tank, and the first expansion device 66 is configured to reduce the pressure of (e.g., expand) the liquid working fluid received from the condenser 34. During the expansion process, a portion of the liquid working fluid may vaporize, and thus, the intermediate vessel 70 may be used to separate the vapor working fluid from the liquid working fluid received from the first expansion device 66. Additionally, due to the pressure drop experienced by the liquid working fluid upon entering the intermediate vessel 70 (e.g., due to the rapid increase in volume experienced upon entering the intermediate vessel 70), the intermediate vessel 70 may provide further expansion of the liquid working fluid. The vapor working fluid in the intermediate vessel 70 may be drawn by the compressor 32 via a suction line 74 of the compressor 32. In other embodiments, the vapor working fluid in the intermediate vessel 70 may be drawn to an intermediate stage (e.g., other than the suction stage) of the compressor 32. Due to the expansion of the working fluid at the expansion device 66 and / or in the intermediate vessel 70, the liquid working fluid collected in the intermediate vessel 70 may be at a lower enthalpy than the liquid working fluid exiting the condenser 34. The liquid working fluid from the intermediate vessel 70 may then flow through line 72 and through the second expansion device 36 to the evaporator 38 .

[0023] According to this embodiment, the compressor 32 may be a centrifugal compressor with a suspended rotor or shaft (e.g., a hermetic compressor). To this end, the vapor compression system 14 includes a bearing system having one or more bearings configured to support the load of the compressor 32 shaft. The bearing system is configured to direct a pressurized fluid (e.g., liquid, working fluid, refrigerant) through the bearings, and the bearings are configured to discharge the fluid toward and against the shaft to achieve suspension of the shaft within the compressor 32. Specifically, the bearings include one or more porous bearing elements configured to receive the pressurized fluid and direct it toward the shaft within the compressor 32 housing. In this manner, the bearing system can support the load on the shaft and enable rotation of the shaft within the compressor 32 housing during operation of the vapor compression system 14. As discussed herein, the pressurized fluid can be a portion of the working fluid (e.g., refrigerant) circulating through the vapor compression system 14. Consequently, the vapor compression system 14 can avoid utilizing a dedicated lubricant (such as oil) to support and rotate the compressor 32 shaft. Furthermore, the bearing system can be integrated with the vapor compression system 14 at a reduced cost compared to other existing bearing system designs. The disclosed embodiments also enable improved (eg, simplified) control of the bearing system and promote more efficient operation of the vapor compression system 14 .

[0024] Considering the above, Figure 5 FIG2 is a cross-sectional side view of an embodiment of a compressor 32 including a bearing system 100 according to aspects of the present disclosure. The compressor 32 may include a housing 102 and a shaft 104 extending through the housing 102. The compressor 32 may also include an impeller 106 coupled to the shaft 104, such as via fasteners 108. During operation of the compressor 32, the shaft 104 may rotate (e.g., via operation of the motor 50) and cause the impeller 106 to rotate. The rotation of the impeller 106 may drive a working fluid (e.g., refrigerant) through a working fluid flow path 110 (e.g., from the evaporator 38, from the intermediate reservoir 70, or from a working fluid circuit) to draw the working fluid into the housing 102 via a suction port 112 and toward the impeller 106. The impeller 106 may transfer mechanical energy to the working fluid and discharge the working fluid to a diffuser passage 114 of the compressor 32. The working fluid may be directed from the diffuser passage 114 to a volute 116 of the compressor 32 , and from the volute 116 to a condenser (eg, condenser 34 ) to exchange heat with a fluid, such as a cooling fluid.

[0025] In the illustrated embodiment, the compressor 32 (e.g., the bearing system 100) includes a first bearing 118 (e.g., a radial bearing, a bearing assembly, a porous bearing) and a second bearing 120 (e.g., a radial bearing, a bearing assembly, a porous bearing) configured to control and / or adjust the position (e.g., radial position) of the shaft 104 relative to an axis 122 (e.g., a rotational axis, a central axis) of the shaft 104. For example, the first and second bearings 118, 120 may be configured to support a load on the shaft 104 such that the shaft 104 is suspended within the first and second bearings 118, 120. The first and second bearings 118, 120 may also be configured to prevent movement of the shaft 104 transverse to the axis 122 (e.g., bending, radial movement, eccentric rotation). The compressor 32 (e.g., the bearing system 100) further includes a third bearing 124 (e.g., a thrust bearing, an axial bearing, a bearing assembly, a porous bearing) configured to control and / or adjust the position (e.g., axial position) of the shaft 104 along the axis 122. For example, the third bearing 124 may be configured to prevent or limit movement (eg, translation) of the shaft 104 along the axis 122 .

[0026] As mentioned above, the bearing system 100 is configured to direct a pressurized fluid to the bearings of the bearing system 100, such as the first bearing 118, the second bearing 120, and / or the third bearing 124. The pressurized fluid can be the same working fluid (e.g., a refrigerant) as the working fluid circulated through the vapor compression system 14 having the compressor 32. However, it should be understood that the pressurized fluid can be any suitable fluid, such as a refrigerant, a condensable vapor, or other fluid. In some embodiments, the first bearing 118, the second bearing 120, and / or the third bearing 124 each include one or more porous elements 126 configured to direct the pressurized fluid therethrough. For example, the one or more porous elements 126 of the first bearing 118 and the second bearing 120 can be configured to receive the pressurized fluid and direct the pressurized fluid toward the shaft 104 to establish a high-pressure fluid film (e.g., a vapor film) around the shaft 104 between the first bearing 118 and the second bearing 120 and the shaft 104. In this manner, the pressurized fluid can levitate the shaft 104 from the first bearing 118 and the second bearing 120, thereby enabling the desired rotation of the shaft 104 about the axis 122. The one or more porous elements 126 of the third bearing 124 can receive the pressurized fluid and direct the pressurized fluid toward a collar 128 (e.g., a thrust collar) of the third bearing 124. In this manner, the pressurized fluid can exert a force on the collar 128 and enable adjustable positioning of the shaft 104 along the axis 122.

[0027] The bearing system 100 includes a fluid supply system 130 configured to supply pressurized fluid to the bearings (the first bearing 118, the second bearing 120, and / or the third bearing 124) of the bearing system 100. For example, the fluid supply system 130 may direct the pressurized fluid through the housing 102 of the compressor 32 to one or more bearing housings 132 (e.g., casings) of the first bearing 118, the second bearing 120, and the third bearing 124. In the illustrated embodiment, one bearing housing 132 is associated with the first bearing 118, and another bearing housing 132 is associated with the second bearing 120. Additional bearing housings 132 may be used with the third bearing 124. In other embodiments, the second bearing 120 and the third bearing 124 may be housed together in a common bearing housing 132. The pressurized fluid may be directed through the bearing housings 132 to the corresponding porous element 126 held within each bearing housing 132. The fluid supply system 130 is described in further detail below. It should be appreciated that the compressor 32 may include any suitable number or type (eg, radial, axial) of bearings incorporating the present technology, and the bearings may be positioned at any suitable location within the casing 102 of the compressor 32 .

[0028] Figure 6 FIG2 is a schematic diagram of an embodiment of a vapor compression system 14 (e.g., an HVAC&R system) including a bearing system 100 for a compressor 32. The vapor compression system 14 includes elements similar to those discussed above, including the compressor 32, a motor 50, a condenser 34, and an evaporator 38 (e.g., a falling-film evaporator) arranged along a working fluid circuit 200 (e.g., a refrigerant circuit). In accordance with the present technology, the bearing system 100 also includes a fluid supply system 130 configured to direct pressurized fluid to a bearing (e.g., the first bearing 118) of the bearing system 100. Specifically, the fluid supply system 130 is configured to direct a portion of the working fluid (e.g., refrigerant) circulating through the working fluid circuit 200 to the bearing assembly 150. To this end, the fluid supply system 130 includes a lubricant circuit 202 (e.g., a fluid supply circuit) extending from the working fluid circuit 200 to the bearing assembly 150 via a fluid conduit 203.

[0029] In the illustrated embodiment, a lubricant circuit 202 extends from a liquid line portion 204 of the working fluid circuit 200 to one or more bearing assemblies in the bearing assembly 150. The liquid line portion 204 extends from the condenser 34 to the evaporator 38. Therefore, the working fluid within the liquid line portion 204 may be in a liquid phase. Various components are disposed along the lubricant circuit 202 and configured to achieve the desired supply of working fluid to the bearing assembly 150 so that the bearing assembly 150 can support the load of the shaft 104 of the compressor 32. For example, the fluid supply system 130 includes a pump 206 (e.g., a liquid pump) disposed along the lubricant circuit 202 and configured to direct a flow of working fluid (e.g., liquid working fluid) from the liquid line portion 204 of the working fluid circuit 200 along the lubricant circuit 202 to the bearing assembly 150 of the motor 50 (e.g., the compressor 32). In some embodiments, the pump 206 may be a linear piston pump and may be driven via a solenoid coil, an electric motor, and / or via another suitable technology. In some embodiments, pump 206 may operate without the use of oil or other specialized lubricants.

[0030] The fluid supply system 130 also includes an accumulator 208 fluidly coupled to the lubricant circuit 202. The accumulator 208 is fluidly coupled to the lubricant circuit 202 downstream of the pump 206 relative to the flow of the working fluid along the lubricant circuit 202. Thus, the accumulator 208 can receive a pressurized flow of working fluid (e.g., liquid working fluid, vapor working fluid, or both) from the pump 206 and the lubricant circuit 202. It should be understood that the accumulator 208 is configured to store pressurized working fluid therein. For example, the accumulator 208 can include a container 210 and a separator 212 (e.g., a bladder, diaphragm, piston, etc.) disposed therein. In some embodiments, the separator 212 can separate the internal volume of the container 210 into a biasing chamber 214 (e.g., a gas chamber) located on a first side of the separator 212 and a fluid chamber 216 (e.g., a liquid chamber, a working fluid chamber) located on a second side of the separator 212. The fluid chamber 216 of the accumulator 208 is configured to receive pressurized working fluid from the lubricant circuit 202. The separator 212 may be a bladder or other flexible container pre-filled with a gas (e.g., nitrogen) to maintain the pressure of the working fluid within the fluid chamber 216. In other embodiments, the biasing chamber 214 may be pre-filled with a gas. In still further embodiments, the biasing chamber 214 may instead include a spring or other mechanical biasing member. In any case, the accumulator 208 may operate as a mechanical battery configured to provide a supply (e.g., temporary supply) of pressurized working fluid from the fluid chamber 216 to the bearing assembly 150 via the lubricant circuit 202, such as during periods of non-operation of the pump 206. For example, during periods of interruption in operation of the pump 206, the accumulator 208 may discharge the pressurized working fluid to the lubricant circuit 202 for supply to the bearing assembly 150. In this manner, the bearing assembly 150 can continue to operate to support the load on the shaft 104 when operation of the pump 206 is resumed and / or when operation of the compressor 32 (e.g., the motor 50) is paused in a controlled manner. In some embodiments, the accumulator 208 can also be operated to dampen oscillations in the flow of pressurized working fluid directed to the bearing assembly 150. Further, the accumulator 208 can be configured to supply pressurized working fluid to the bearing assembly 150 when the vapor compression system 14 is started (e.g., before the pump 206 and / or the compressor 32 are operated).

[0031] The fluid supply system 130 may also include other components disposed along the lubricant circuit 202, such as a check valve 218 disposed between the pump 206 and the accumulator 208. The check valve 218 may be configured to close and prevent the flow of the liquid working fluid from the pump 206 toward the bearing assembly 150 based on the pressure of the liquid working fluid discharged by the pump 206. For example, in response to the pressure of the liquid working fluid dropping below a threshold value (e.g., a threshold value corresponding to the desired pressure of the liquid working fluid supplied to the bearing assembly 150), the check valve 218 may close. In such a case, the pressurized liquid working fluid stored in the accumulator 208 may be supplied to the bearing assembly 150 (e.g., the closed check valve 218 prevents the working fluid from flowing back into the pump 206), enabling at least temporary continued operation of the bearing assembly 150 to support the shaft 104. The check valve 218 may be a ball check valve, a diaphragm check valve, a swing check valve, a stop check valve, a lift check valve, an inline check valve, or any other suitable valve.

[0032] In some embodiments, the fluid supply system 130 may include a filter 220 disposed along the lubricant circuit 202 (e.g., downstream of the accumulator 208 and upstream of the bearing assembly 150). The filter 220 may be configured to remove particles and / or moisture (e.g., water, water vapor) from the liquid working fluid before the liquid working fluid is directed to the bearing assembly 150.

[0033] The fluid supply system 130 may also include a heat exchanger 222 disposed along the lubricant circuit 202. The heat exchanger 222 is disposed upstream of the pump 206 relative to the flow of the working fluid through the lubricant circuit 202. In some embodiments, the heat exchanger 222 may be a brazed plate heat exchanger. In operation, the heat exchanger 222 may function as a subcooler configured to subcool the working fluid introduced from the liquid line portion 204 into the lubricant circuit 202. In this manner, the heat exchanger 222 may operate to ensure that the working fluid supplied to the pump 206 is in a liquid phase, which may reduce undesirable effects such as flashing of the working fluid at the pump 206 and cavitation of the pump 206. The heat exchanger 222 is configured to place the working fluid drawn from the liquid line portion 204 in heat exchange relationship with a cooling fluid (e.g., an auxiliary cooling fluid) introduced to the heat exchanger 222 via a cooling fluid circuit 224. In some embodiments, the cooling fluid may be water. In such embodiments, the cooling fluid circuit 224 may be configured to supply the cooling fluid from an external source. Additionally or alternatively, the cooling fluid circuit 224 can be configured to supply water or other cooling fluid (e.g., cooled via the evaporator 38) from a conditioning fluid conduit (such as the supply line 60S and / or the return line 60R described above). In some embodiments, the cooling fluid can be another portion of the working fluid from the working fluid circuit 200. In such embodiments, the cooling fluid circuit 224 can extend from the working fluid circuit 200 (e.g., the liquid line portion 204) to the heat exchanger 222. However, it should be understood that the cooling fluid circuit 224 can be configured to direct any suitable cooling fluid to the heat exchanger 222 to achieve cooling (e.g., subcooling) of the portion of the working fluid along the lubricant circuit 202 toward the bearing assembly 150 of the compressor 32.

[0034] As mentioned above, the bearing assemblies 150 are configured to receive a pressurized fluid (e.g., a working fluid, a refrigerant) and discharge the fluid toward the shaft 104 or the collar 128. Specifically, the bearing assemblies 150 each include one or more porous elements configured to direct the pressurized working fluid therethrough, flash vaporize the pressurized working fluid, and discharge the pressurized vapor working fluid toward the shaft 104 or the collar 128. The working fluid may then flow through the housing 102 of the compressor 32 (e.g., the motor 50) to one or more drain lines 226 of the bearing system 100. For example, the bearing system 100 may include a first drain line 228 extending from the housing 102 to the liquid line portion 204 of the working fluid circuit 200. The first drain line 228 may include a valve 230 (e.g., an electronic expansion valve) and / or may be configured to direct the vapor working fluid from the housing 102 to the liquid line portion 204 of the working fluid circuit 200. Additionally or alternatively, the bearing system 100 may include a second drain line 232 extending from the housing 102 to the evaporator 38, and / or a third drain line 234 extending from the housing 102 to the evaporator 38. In some embodiments, the second drain line 232 is configured to direct the vapor working fluid from the housing 102 to the evaporator 38, and the third drain line 234 is configured to direct the liquid working fluid from the housing 102 to the evaporator 38.

[0035] The vapor compression system 14 may also include a controller 250 (e.g., a control system, control panel, or control panel) that is communicatively coupled to one or more components of the vapor compression system 14 and / or the bearing system 100. The controller 250 is configured to monitor, regulate, and / or otherwise control the operation of the components of the vapor compression system 14 and / or the bearing system 100. For example, one or more control transmission devices, such as wires, cables, wireless communication devices, and the like, may be communicatively coupled to the compressor 32, the motor 50, the pump 206, and / or other components described herein. Such components may include a network interface that enables the components of the vapor compression system 14 and / or the bearing system 100 to communicate via various protocols, such as EtherNet / IP, ControlNet, DeviceNet, or any other communication network protocol. Alternatively, the communication components may enable the components of the vapor compression system 14 and / or the bearing system 100 to communicate via mobile telecommunication technology, Bluetooth®, near-field communication technology, and the like.

[0036] In some embodiments, the controller 250 may include part or all of the control panel 40, or may be another suitable controller included in the vapor compression system 14 and / or the bearing system 100. In any case, the controller 250 may be configured to control components of the vapor compression system 14 and / or the bearing system 100 according to the techniques discussed herein. The controller 250 includes a processing circuit system 252, such as one or more microprocessors, which may execute software for controlling components of the vapor compression system 14 and / or the bearing system 100. The processing circuit system 252 may include multiple microprocessors, one or more "general purpose" microprocessors, one or more special-purpose microprocessors and / or one or more application-specific integrated circuits (ASICS), or some combination thereof. For example, the processing circuit system 252 may include one or more reduced instruction set (RISC) processors.

[0037] The controller 250 may also include a memory device 254 (e.g., memory) that may store information such as instructions, control software, lookup tables, configuration data, and the like. The memory device 254 may include volatile memory, such as random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM). The memory device 254 may store a variety of information and may be used for a variety of purposes. For example, the memory device 254 may store processor-executable instructions, including firmware or software, for execution by the processing circuitry 252, such as instructions for controlling components of the vapor compression system 14 and / or the bearing system 100. In some embodiments, the memory device 254 is a tangible, non-transitory, machine-readable medium that may store machine-readable instructions for execution by the processing circuitry 252. The memory device 254 may include ROM, flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. The memory device 254 may store data, instructions, and any other suitable data. It should be understood that memory device 254 may store processor-executable instructions (e.g., for execution via processing circuitry 252) to implement the operation of any of the components described herein and to implement any of the functions and / or operations described herein.

[0038] The controller 250 can be configured to control the operation of components of the vapor compression system 14 and / or the bearing system 100 based on detected operating parameters of the vapor compression system 14 and / or the bearing system 100. To this end, the vapor compression system 14 includes one or more sensors 256 configured to detect operating parameters associated with or indicative of operating conditions of the vapor compression system 14 and the bearing system 100. For example, one or more of the sensors 256 can be disposed along the lubricant circuit 202 and can be configured to detect operating parameters of the working fluid directed through the lubricant circuit 202, such as temperature, pressure, flow rate, etc. In some embodiments, the one or more sensors 256 can be configured to detect operating parameters associated with the motor 50, such as the rotational speed of the shaft 104, the torque on the shaft 104, the temperature of the motor 50, etc. The one or more sensors 256 can be configured to detect operating parameters of the bearing assembly 150, such as detecting whether one or more bearing assemblies 150 are in contact (e.g., physical contact) with the shaft 104, as further described below.

[0039] In some embodiments, one of the sensors 256 can be configured to detect an operating parameter associated with the accumulator 208, such as the pressure of the working fluid within the fluid chamber 216 and / or the pressure of the gas within the bias chamber 214. Additionally or alternatively, one or more of the sensors 256 can be configured to detect a level of the working fluid within the condenser 34, which can be used as a reference before and / or during startup of the bearing system 100 and / or the vapor compression system 14. It should be understood that each sensor 256 included in the vapor compression system 14 can be communicatively coupled to the controller 250. Thus, the controller 250 can receive data and / or feedback from the sensors 256 and can control the operation of the vapor compression system 14 and / or the bearing system 100 based on the feedback and / or data.

[0040] Figure 7FIG2 is a cross-sectional side view of an embodiment of a pump 206 according to aspects of the present disclosure. As discussed above, the pump 206 is configured to pump a working fluid along the lubricant circuit 202 toward the bearing assembly 150. The pump 206 includes an inlet 300 (e.g., an inlet port) configured to receive a flow of working fluid into a pump body 302 (e.g., a pump housing), and an outlet 304 (e.g., a discharge port, an outlet valve) configured to discharge the working fluid from the pump body 302 and direct the working fluid toward the bearing assembly 150. Furthermore, the pump 206 may include a piston 306 (e.g., a booster piston) at least partially disposed within the pump body 302. The piston 306 is configured to move back and forth (e.g., reciprocate) within the pump body 302 to pressurize the working fluid. That is, the piston 306 may reciprocate, including a compression stroke in a forward direction 308 and a return stroke in a return direction 310. During the return stroke, the piston 306 may draw the working fluid into the pump body 302 via the inlet 300. The piston 306 may then reverse direction to perform a compression stroke and pressurize the working fluid and expel it from the pump body 302 via the outlet 304 .

[0041] The pump body 302 can be coupled (e.g., removably coupled) to a piston housing 311. The movement of the piston 306 can be driven by a solenoid coil 312 disposed about (e.g., surrounding, enclosing) the piston housing 311 with the piston 306. The operation of the solenoid coil 312 can be controlled by a pump controller 314. The pump controller 314 can include memory and processing circuitry (e.g., one or more processors). In some embodiments, the pump controller 314 can be a standalone controller, while in other embodiments, the pump controller 314 can be a component of and / or integrated with another controller of the vapor compression system 14 (e.g., the control panel 40, the controller 250). For example, the pump controller 314 can include the embodiments of the processing circuitry 252 and the memory device 254 described above. The pump controller 314 can direct current through the solenoid coil 312, thereby inducing a magnetic force on the piston 306, causing the piston 306 to move in a forward direction 308 or a return direction 310, depending on the direction of the current passing through the solenoid coil 312.

[0042] The pump 206 may include a compression chamber 316 (e.g., a high-pressure chamber, a liquid chamber, a compression chamber) within a piston housing 311 that is fluidly coupled to the lubricant circuit 202 (e.g., the inlet 300). The piston 306 may include a plunger section 318 configured to extend into the compression chamber 316 to pressurize the working fluid (e.g., during a compression stroke). During a return stroke, the plunger section 318 may retract from the compression chamber 316, which may draw the working fluid through the inlet 300 and into the compression chamber 316. For example, movement of the piston 206 in the return direction 310 increases the volume of the compression chamber 316, thereby creating a pressure differential across the inlet 300. As a result, the working fluid may flow through the inlet 300 into the volume of the compression chamber 316 vacated by the retraction of the plunger section 318.

[0043] Inlet 300 may be a one-way valve (e.g., a check valve) configured to selectively allow working fluid to flow into pump body 302, as shown. For example, inlet 300 may include a hinged door 320 (e.g., a hinged valve, a check valve, a valve, an inlet valve), or other valve member configured to pivot (e.g., open) inwardly toward compression chamber 316. A pressure differential (e.g., a threshold pressure differential) across hinged door 320 may cause working fluid to push hinged door 320 open and flow into compression chamber 316. In particular, the return stroke of piston 306 may create a low-pressure region in compression chamber 316 relative to the pressure of the working fluid upstream of pump 206. Consequently, pump 206 may draw working fluid into first chamber 206 during the return stroke. Inlet 300 may include a sealing seat 322 against which hinged door 320 may rest in a normally closed position, preventing working fluid from compression chamber 316 from exiting inlet 300 (e.g., in an upstream direction). For example, if the pressure in the compression chamber 316 is greater than the pressure upstream of the inlet 300 (e.g., during a compression stroke), the higher-pressure working fluid in the compression chamber 316 can bias the hinged door 320 against the sealing seat 322, thereby closing the inlet 300. In this manner, the hinged door 320 can allow working fluid to flow into the pump 206 (e.g., during a return stroke) while preventing working fluid from exiting the pump 206 in the opposite direction (e.g., during a compression stroke). In some embodiments, the hinged door 320 can be biased toward the closed position (e.g., via a spring or other biasing element), such that the hinged door 320 is configured to transition from the closed position toward the open position when a threshold pressure differential (e.g., greater than zero) is applied across the hinged door 320. Thus, when no pressure differential exists across the hinged door 320 (e.g., at the end of each stroke), the inlet 300 can be in the closed position against the sealing seat 322.

[0044] Outlet 304 may be a one-way valve (e.g., a check valve) configured to enable the flow of working fluid out of pump 206 toward bearing assembly 150 and also to prevent the backflow of working fluid into pump 206. A pressure differential (e.g., a threshold pressure differential) across outlet 304 may cause outlet 304 (e.g., an outlet valve) to open, thereby allowing the flow of working fluid therethrough. In particular, the compression stroke of piston 306 may create a high-pressure region in compression chamber 316 relative to lubricant circuit 202 downstream of pump 206. Consequently, the valve (e.g., a ball valve) of outlet 304 may be biased open, and pump 206 may direct working fluid from compression chamber 316 out of outlet 304 during the compression stroke. Thus, inlet 300 and outlet 304 may open and close in coordination, allowing pump 206 to maintain a continuous flow of pressurized working fluid through pump 206 and in a downstream direction toward bearing assembly 150. In some embodiments, the outlet 304 may include a check valve (eg, a ball check valve) having a ball 324 and a spring 326 that urges the ball 324 toward a closed or sealing position (eg, resisting the flow of the working fluid).

[0045] In addition to the compression chamber 316, the pump 206 also includes a piston cavity 328 (e.g., a second chamber, a low-pressure chamber, or a vapor chamber), which may be separated from the compression chamber 316 by a dust seal 330. The piston cavity 328 may be formed within and / or by the piston housing 311, and the piston 206 may be disposed within the piston cavity 328. The plunger section 318 of the piston 306 translates (e.g., reciprocates, oscillates) between the compression chamber 316 and the piston cavity 328. For example, during a return stroke, the plunger section 318 at least partially retracts from the compression chamber 316 and extends further into the piston cavity 328. During this translation, the plunger section 318 may maintain contact with the dust seal 330, thereby at least partially preventing the flow of working fluid between the compression chamber 316 and the piston cavity 328. In some embodiments, the dust seal 330 can allow some of the working fluid to flow from the compression chamber 316 into the piston cavity 328, such as in a controlled manner. The piston 306 also includes a head section 332 (e.g., a head portion) at the return end (e.g., first end) of the plunger section 318. The head section 332 is configured to translate back and forth (e.g., reciprocate, oscillate) within the piston cavity 328 (e.g., piston housing 311), thereby driving the plunger section 318 in and out of the compression chamber 316. As shown, the head section 332 can have a larger diameter than the plunger section 318.

[0046] The piston cavity 328 can contain vapor 341, such as a working fluid in a gaseous phase. In some embodiments, the vapor 341 can be a portion of the working fluid that flows from the compression chamber 316 across the dust seal 330 and into the piston cavity 328. Additionally, in some embodiments, the pump 206 can include a bypass conduit 334 (e.g., a bypass channel, a bypass port) extending between the compression chamber 316 and the piston cavity 328 (e.g., extending from the compression chamber and into the piston cavity) to enable a portion of the working fluid (e.g., vapor 341) to bypass the dust seal 330 and flow from the compression chamber 316 to the piston cavity 328. When the working fluid enters the piston cavity 328, it can vaporize (e.g., flash evaporate) due to the drop in pressure. As the head section 332 moves (e.g., translates, oscillates) within the piston cavity 328, the vapor 341 can flow across the portion of the piston 306 within the piston cavity 328 and cool it.

[0047] As discussed above, the piston 306 may be driven by a solenoid coil 312 that induces a magnetic force on the piston 306. In some cases, the heat generated by the magnetic induction may reduce the performance and / or life of the pump 206. To facilitate cooling of the piston 306, the pump 206 may include a heat sink 336 (e.g., a heat dissipation element) coupled to the piston 306. The heat sink 336 may be formed from a non-magnetic material so that the induced magnetic force does not act on the heat sink 336 and / or cause heat generation within the heat sink. The heat sink 336 may be coupled to (e.g., clamped to) the piston 306. In some embodiments, the heat sink 336 may not contact the walls (e.g., the inner walls) of the piston cavity 328. That is, a gap (e.g., a radial gap, a clearance, a space) may exist between the heat sink 336 and the walls of the piston cavity 328. The vapor working fluid (e.g., vapor 341) within the piston cavity 328 can flow across the heat sink 336 (e.g., during the compression stroke) to cool the piston 306 (e.g., via heat transfer from the heat sink 336 and / or the piston 306 to the vapor working fluid). In some embodiments, the vapor 341 can also absorb heat from the solenoid coil 312. In some embodiments, the pump 206 can include a bleed port 338 through which the vapor 341 can exit the pump 206 from the piston cavity 328. The bleed port 338 can direct the vapor 341 (e.g., vapor working fluid) to the working fluid circuit 200, such as to selected components of the working fluid circuit 200 (e.g., the evaporator 38, the compressor 32, the discharge line 226).

[0048] Pump 206 may include one or more piston rings 340 disposed about piston 306 (e.g., head section 332). In some embodiments, piston rings 340 may be configured to control the flow of vapor 341 within piston cavity 328. To this end, at least one of piston rings 340 may be provided with ports (e.g., including one or more ports 339, such as axial ports formed therein) or include recesses to enable vapor 341 to flow across piston 306 and within piston cavity 328 in a desired manner. In this manner, piston rings 340 may be configured to flow vapor 341 across piston 306 and throughout piston cavity 328, thereby cooling piston 306 via vapor 341. Additionally, piston rings 340 may be configured to contact the walls of piston cavity 328, thereby enabling heat transfer between piston 306, piston housing 311, and the working fluid.

[0049] The operation of the pump 206 may be controlled by a pump controller 314. To this end, the pump controller 314 may supply or control the supply of current to the solenoid coil 312. The pump controller 314 may adjust the amplitude and / or other characteristics of the current to control the magnitude of the magnetic force generated by the solenoid coil 312 and applied to the piston 306. Furthermore, the pump controller 314 may change the direction of the current flowing through the solenoid coil 312 to reverse the polarity of the solenoid coil 312 and, therefore, the direction of the magnetic force acting on the piston 306. For example, to drive the piston 306 in the forward direction 308 at a specific acceleration, the pump controller 314 may direct a current of a specific magnitude (e.g., amperage) through the solenoid coil 312 in a specific direction. To reduce the acceleration of the piston 306, the pump controller 314 may reduce the magnitude of the current. To decelerate or change the direction of the piston 306 (e.g., from the forward direction 308 to the return direction 310), the pump controller 314 may reverse the direction of the current flowing through the solenoid coil 312. In this manner, the movement of piston 306 within piston housing 311 (e.g., velocity, acceleration, force, momentum, kinetic energy) can correspond to the electrical input (e.g., current, voltage, power) provided to solenoid coil 312. In some embodiments, pump controller 314 can control the electrical input based on a current profile configured to achieve a desired motion pattern for piston 306. For example, the current profile for the compression stroke of piston 306 can be a function of current versus time, selected to cause piston 306 to accelerate in forward direction 308 for a specific period of time, decelerate for another period of time, and then reverse direction into the return stroke. However, given a specific current profile, the operating conditions of pump 206 (e.g., no-load) can cause variations in the behavior of pump 206. Furthermore, under certain operating conditions, such as when the return stroke velocity of piston 306 is too rapid, cavitation of the working fluid can occur. Therefore, it may be desirable to adjust the current profile in response to the speed or frequency of pump 206 (e.g., piston 306), which can be determined based on sensed operating conditions.

[0050] The pump 206 includes a respective block stop 342 at each end of the piston cavity 328. Each block stop 342 can be configured to mechanically stop the piston 306 in response to contact between the block stop 342 and the piston 306. In the illustrated embodiment, the pump 206 includes two block stops 342, such as a forward block stop 343 and a return block stop 345. Each block stop 342 is positioned at a respective end of travel of the head section 332 within the piston cavity 328. As discussed in further detail below, the block stops 342 can provide a mechanical stop for the piston 306 at the end of each stroke. Additionally, each block stop 342 can include an internal switch 344 (e.g., an internal switching mechanism) configured to provide a signal to the pump controller 314 indicating contact between the piston 306 and the block stop 342. To enable electrical communication between the block stops 342, the pump controller 314, and / or the solenoid coil 312, the pump 206 may include an electrical feedthrough 346 through which electrical conduits (e.g., wires) may extend to electrically couple the pump controller 314 to one or more components of the pump 206 (e.g., the internal switch 344). For example, wires 348 may extend through the electrical feedthrough 346 to connect the pump controller 314 to contacts of the internal switch 333 of one or more of the block stops 342. Additionally, the wires 348 may feed current from the power source and / or the pump controller 314 to the solenoid coil 312 to enable operation of the pump 206 as described above.

[0051] Figure 8 and Figure 9 A schematic cross-sectional side view of a portion of an embodiment of a piston 306 is shown illustrating the operation of an internal switch 344 of one of the forward block stops 343. For example, the illustrated embodiment shows contact between the piston 306 and the forward block stop 343 (e.g., the first block stop) at the end of the compression stroke. Figure 8 and Figure 9 A forward block stop 343 is shown at the forward end of the piston cavity 328 , but the techniques described in the following discussion are similarly applicable to a second block stop (eg, return block stop 345 ) provided at the return end of the piston 306 opposite the forward end.

[0052] The forward block stop 343 includes a body 370, which may be formed from a conformable (e.g., compressible), non-conductive material, such as an elastomer (e.g., silicone, rubber). Thus, the forward block stop 343 can be configured to at least partially absorb forces applied to the body 370 during contact between the forward block stop 343 and the piston 306. In this manner, the forward block stop 343 can be configured to controllably stationary (e.g., in a resting state) the piston 306 at the end of its stroke. The internal switch 344 of the forward block stop 343 includes a floating contact 372 encased within the body 370, such that the floating contact 372 can move in response to the application of force to the body 370 (e.g., during compression of the body 370). Furthermore, the forward block stop 343 includes a contact 374 that is stationary relative to the pump 206 (e.g., relative to the body 370 and / or the floating contact 372). For example, the fixed contact 374 can be coupled to the pump body 302 so that the fixed contact 374 does not move even if the piston 306 contacts and compresses the main body 370. The fixed contact 374 can include a first flange 376 disposed around (e.g., annularly around) the main body 370 and a second flange 378 extending radially toward (e.g., into) the main body 370. When the main body 370 is in an uncompressed or stationary state of the forward block stop 343, the second flange 378 can contact the floating contact 372, as shown. Figure 8 As shown. That is, the body 370 can resiliently bias the floating contact 372 into abutment with the fixed contact 374, thereby establishing electrical continuity between the floating contact 372 and the fixed contact 374. In this manner, the electrical connection between the floating contact 372 and the fixed contact 374 can be normally closed. It should be understood that contact (e.g., electrical continuity) between the floating contact 372 and the fixed contact 374 can indicate non-contact between the piston 306 and the block 342. Therefore, detection of electrical discontinuity between the floating contact 372 and the fixed contact 374 can indicate that the piston 306 has reached the end of its compression stroke.

[0053] like Figure 9 As shown, piston 306 can contact (e.g., impact, abut) body 370 of forward block stop 343 at the end of its compression stroke. Consequently, body 370 can compress (e.g., elastically deform), and the force of piston 306 can cause floating contact 372 to translate in forward direction 308, temporarily breaking physical contact, and therefore electrical connection, between fixed contact 374 and floating contact 372. Subsequently, in some cases, as body 370 decompresses and returns to a resting or undeformed state, the movement of piston 306 can reverse (e.g., rebound) away from forward block stop 343 (e.g., in reverse direction 310). Consequently, floating contact 372 can return to contact fixed contact 374, reestablishing electrical connection therebetween.

[0054] The pump controller 314 can monitor electrical continuity between the floating contact 372 and the fixed contact 374 to detect the impact of the piston 306 against the forward block stop 343, which can correspond to the end of the compression stroke. For example, the pump controller 314 can monitor the probe wire 380 extending through the electrical feedthrough 346 to measure the voltage between (e.g., across) the fixed contact 374 and the floating contact 372. A detected low voltage (e.g., zero) can indicate contact (e.g., physical contact) between the fixed contact 374 and the floating contact 372. A detected high voltage (e.g., greater than zero) can indicate non-contact (e.g., physical separation) between the fixed contact 374 and the floating contact 372. In response to detecting that the fixed contact 374 is not contacting the floating contact 372, the pump controller 314 can determine that the piston 306 is at the end of its stroke.

[0055] In response to detecting the impact of piston 306 on block stop 342, pump controller 314 may reverse the direction of current supplied to solenoid coil 312 to reverse the direction of movement of piston 306 within piston housing 311. For example, in response to detecting a disconnection between floating contact 372 and fixed contact 374 of forward block stop 343, pump controller 314 may reverse the direction of current directed through solenoid coil 312 to cause the piston to travel in return direction 310 and thereby initiate a return stroke after the compression stroke of piston 306 is complete. The motion profile (e.g., velocity or acceleration over time) of each stroke may be controlled based on a current profile. For example, the current profile may map current values ​​to nominal or expected acceleration values. Pump controller 314 may then achieve the desired acceleration value by supplying corresponding current values ​​based on the current profile.

[0056] In some circumstances (e.g., under certain operating conditions), the current profile can be adjusted (e.g., via pump controller 314) to achieve adjusted operation of piston 306. For example, the current profile can be adjusted based on one or more detected operating parameters and / or operating conditions of pump 206. In some embodiments, the current profile can be adjusted to avoid and / or mitigate cavitation and / or conditions indicative of cavitation in pump 206. For example, depending on operating conditions (e.g., the temperature of the working fluid) and the speed of pump 206, the return stroke can introduce localized low-pressure areas within pump 206 where the working fluid can cavitate. This cavitation of the working fluid can introduce inefficiencies and wear to pump 206. Therefore, pump controller 314 can utilize the methods described herein to adjust the motion of piston 306 (e.g., the speed of the return stroke) to reduce cavitation.

[0057] Figure 10A flow chart illustrating an embodiment of a method 400 that can be executed by the pump controller 314 to adjust the operation (e.g., movement) of the piston 306, such as based on sensed feedback or data (e.g., feedback indicating cavitation or potential cavitation). For example, the pump controller 314 can determine a change in the interval, period, frequency, and / or speed of the piston 306's strokes (e.g., consecutive strokes, sequential strokes) from one stroke cycle to the next, such as based on a time period or interval between physical contact of the piston 306 at each of the block stops 342. This change can be a sign of cavitation caused by operation of the pump 206 according to a current profile under specific operating conditions. The pump controller 314 can then adjust the current profile to reduce the likelihood and / or incidence of cavitation.

[0058] At block 402, the pump controller 314 may cause the piston 306 to perform a compression stroke. For example, the pump controller 314 may energize (e.g., supply current to) the solenoid coil 312 according to the direction and magnitude of a specific current profile. The direction and magnitude of the current may be constant or vary throughout the stroke, thereby generating a controlled velocity profile for the piston 306. For example, the current profile may cause the piston 306 to initially accelerate in a forward direction and then decelerate toward the end of the compression stroke. In this manner, the pump controller 314 may energize the solenoid coil to induce a desired magnetic force on the piston in a first direction (e.g., a forward direction, a compression direction).

[0059] At the end of the compression stroke, the piston 306 may contact the forward block stop 343 (e.g., the first block stop) at the forward end of the piston cavity 328. Thus, at block 404, the pump controller 314 may detect contact against the forward block stop 343 based on the disconnection between the fixed contact 374 and the floating contact 372. The internal switch 344 may send a signal to the pump controller 314 indicating contact against the forward block stop 343.

[0060] At block 406, the pump controller 314 may determine the speed of the compression stroke based on the interval between the contact time at the forward block stop 343 and the previous contact time at the return block stop 345 (e.g., the second block stop). The time interval between these two contact moments may correspond to the speed of the compression stroke. For example, at the end of the return stroke, the piston 306 may impact the return block stop 345 at time t1. Then, at the end of the compression stroke, the piston 306 may impact the forward block stop 343 at time t2. The pump controller 314 may then determine that the interval is t2 − t1. Based on this interval, the pump controller 314 may determine the speed of the compression stroke. Alternatively, the pump controller 314 may determine the period or frequency of the pump cycle based on the contact time at the forward block stop 343 and the previous contact time at the forward block stop. For example, the pump controller 314 may detect a first contact at the forward block stop 343 at time t1 and then detect a second contact at the forward block stop 343 at time t2. The pump controller 314 may then determine that the period of the pump cycle is t2 − t1 . In either case, the pump controller 314 determines the time interval between subsequent contacts at one or both of the block stops 342 .

[0061] At block 408, the pump controller 314 may compare the speed of the compression stroke to the speed of a previous compression stroke of the piston 306 (e.g., the immediately preceding compression stroke). For example, the pump controller 314 may compare the time interval determined at block 406 to the previous time interval of the previous compression stroke. Based on the comparison between the two intervals, the pump controller 314 may determine the difference (e.g., change) in speed between the compression stroke and the previous compression stroke. For example, the pump controller 314 may determine that the most recent compression stroke was 100 milliseconds slower than the previous compression stroke. This decrease in speed during the compression stroke may be a sign of cavitation during the return stroke.

[0062] At block 410, the pump controller 314 may determine whether the speed of the compression stroke relative to the previous compression stroke has changed by more than a threshold amount (e.g., zero, 10 milliseconds, 100 milliseconds, etc.). If so (i.e., the difference is significant enough), then at block 412, the pump controller 314 may adjust the current profile based on the difference. For example, the pump controller 314 may adjust the current profile to reduce the speed (e.g., average speed, acceleration) of the return stroke to avoid further cavitation. Then, at block 414, the pump controller 314 may supply current based on the adjusted current profile to initiate the return stroke. In this way, the pump controller 314 can use the change in speed of the compression stroke as feedback to control the current through the solenoid coil 312.

[0063] At block 416, the pump controller 314 may detect contact between the piston 306 and the return block stop 345. In some embodiments, the pump controller 314 may start a timer or store the time at which contact at the return block stop 345 was initiated. In this manner, the interval between contact at the return block stop 345 and subsequent contact at the forward block stop 343 may be determined. In response to detecting contact at the return block stop 345, the pump controller 314 may return to block 402 to supply current to the solenoid coil 312 to initiate the compression stroke. For example, the pump controller 314 may reverse the polarity of the solenoid coil 312, thereby reversing the piston 306 toward the forward direction 308.

[0064] Although only certain features and embodiments have been shown and described, numerous modifications and changes may occur to those skilled in the art without materially departing from the novel teachings and advantages of the subject matter recited in the claims, such as changes in the size, dimensions, structure, shape and proportions of the various components, parameter values ​​(such as temperature and pressure), mounting arrangements, use of materials, color, orientation, etc. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It should be understood, therefore, that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the present disclosure.

[0065] Furthermore, in order to provide a concise description of the exemplary embodiments, not all features of an actual implementation may be described, such as those not relevant to the presently contemplated best mode or those not relevant to enablement. It should be understood that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such development work may be complex and time-consuming, but for those of ordinary skill having the benefit of this disclosure, these are routine tasks of design, fabrication, and production without undue experimentation.

[0066] The technology presented and claimed herein refers to and applies to substantial objects and specific examples of practical nature that improve the technical field of the invention in a demonstrable manner and are therefore not abstract, intangible, or purely theoretical. Further, if any claim appended to the end of this specification contains one or more elements that are expressed as "means for [performing] [the function] ..." or "steps for [performing] [the function] ...", it is intended that such elements will be interpreted in accordance with 35 USC 112(f). However, for any claim containing elements specified in any other manner, it is intended that such elements will not be interpreted in accordance with 35 USC 112(f).

Claims

1. A pump for a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system, the pump comprising: a pump body defining a compression chamber; a piston housing coupled to the pump body, wherein the piston housing includes a piston cavity; a piston disposed within the piston housing, wherein the piston comprises: a plunger section configured to reciprocate between the compression chamber and the piston cavity; and a head section configured to reciprocate within the piston cavity; a solenoid coil configured to induce a magnetic force on the piston; and A controller is configured to control the flow of current through the solenoid coil to control the reciprocating motion of the piston within the piston cavity.

2. The pump according to claim 1, wherein the pump body comprises: an inlet configured to direct fluid into the compression chamber; as well as an outlet configured to discharge the fluid from the compression chamber, The piston is configured to translate in a first direction to draw the fluid into the compression chamber via the inlet, and to translate in a second direction opposite the first direction to force the fluid out of the compression chamber via the outlet.

3. The pump of claim 2 , comprising an inlet valve disposed at the inlet and an outlet valve disposed at the outlet, wherein during translation of the piston in the first direction, the inlet valve is configured to transition to a first open position and the outlet valve is configured to transition to a first closed position, and wherein during translation of the piston in the second direction, the inlet valve is configured to transition to a second closed position and the outlet valve is configured to transition to a second open position.

4. The pump of claim 3, wherein the inlet valve comprises a hinged door, the outlet valve comprises a ball check valve, or both.

5. The pump of claim 1 , wherein the piston housing comprises: a first stopper disposed within the piston cavity, wherein the piston is configured to contact the first stopper at the end of a compression stroke of the piston; as well as A second block stop is disposed within the piston cavity, wherein the piston is configured to contact the second block stop at the end of a return stroke of the piston.

6. The pump of claim 5 , wherein the first block stop comprises a first electrical contact communicatively coupled to the controller and a second electrical contact communicatively coupled to the controller, wherein the controller is configured to detect contact between the piston and the first block stop in response to detection of an electrical discontinuity between the first electrical contact and the second electrical contact.

7. The pump of claim 6 , wherein the first block stop comprises a compliant body, the first electrical contact is a fixed contact, and the second electrical contact is a floating contact disposed within the compliant body, wherein the floating contact is configured to establish electrical continuity with the fixed contact in an uncompressed state of the compliant body, the compliant body is configured to transition to a compressed state in response to contact with the piston, and the compliant body is configured to separate the floating contact from the fixed contact in the compressed state to establish electrical discontinuity between the floating contact and the fixed contact.

8. The pump of claim 5, wherein the controller is communicatively coupled to the first block stop and the second block stop, and the controller is configured to: detecting contact between the piston and the first block stop based on one or more first signals received from the first block stop; detecting contact between the piston and the second block stop based on one or more second signals received from the second block stop; determining a stroke velocity of the piston based on the one or more first signals and the one or more second signals; detecting a change in the stroke velocity; as well as The flow of the electrical current is adjusted based on the change in the stroke velocity.

9. The pump of claim 1 , comprising a bypass conduit extending through the pump body, the piston housing, or both, wherein the bypass conduit extends between the compression chamber and the piston cavity, and the bypass conduit is configured to enable flow of fluid between the compression chamber and the piston cavity.

10. The pump of claim 9, comprising one or more piston rings coupled to the head section of the piston, wherein the piston rings are configured to enable flow of the fluid across the head section from a first end of the head section to a second end of the head section.

11. The pump of claim 1 including a non-magnetic heat sink disposed around the head section of the piston.

12. A heating, ventilation, air conditioning and / or refrigeration (HVAC&R) system comprising: A pump configured to pump fluid along a circuit of the HVAC&R system, wherein the pump comprises: a piston configured to reciprocate within a piston chamber of the piston housing; and a block stopper disposed at an end of the piston chamber, wherein the block stopper includes an internal switch configured to detect contact between the block stopper and the piston; and A controller is configured to control a stroke speed of the piston based on a signal received from the internal switch.

13. The HVAC&R system of claim 12 , comprising the piston housing and a solenoid coil disposed about the piston housing, wherein the solenoid coil is configured to induce a magnetic force to move the piston within the piston chamber, and the controller is configured to regulate the flow of current through the solenoid coil to control the stroke speed of the piston.

14. The HVAC&R system of claim 13, wherein the controller is configured to adjust a current profile of the flow of current through the solenoid coil based on the detected contact between the block stop and the piston.

15. The HVAC&R system of claim 12, comprising the piston housing and a pump body of the pump, wherein the piston housing and the pump body are coupled to each other, and wherein the piston comprises: a plunger section configured to extend into a compression chamber of the pump body to pressurize the fluid during a compression stroke of the piston; as well as A head section is configured to reciprocate within the piston chamber of the piston housing.

16. The HVAC&R system of claim 15, wherein the piston housing includes a piston cavity, and the pump body, the piston housing, or both include a bypass passage configured to enable flow of the fluid from the compression chamber to the piston cavity to cool the piston.

17. The HVAC&R system of claim 12 , comprising the circuit and a compressor configured to circulate a working fluid through a working fluid circuit of the HVAC&R system, wherein the compressor includes a bearing, the circuit extends between the working fluid circuit and the bearing, the fluid includes a portion of the working fluid, and the pump is configured to pump the fluid along the circuit to the bearing.

18. A method of operating a pump, the method comprising: energizing the solenoid coil to cause the piston to translate in a first direction within the piston cavity; detecting a first contact between the piston and a first stop member within the piston cavity; energizing the solenoid coil to cause the piston to translate within the piston cavity in a second direction opposite to the first direction; detecting a second contact between the piston and a second stop member within the piston cavity; determining a time interval between the first contact and the second contact; as well as Energization of the solenoid coil is adjusted based on a difference between the time interval and a previous time interval.

19. The method of claim 18, wherein detecting the first contact comprises detecting a first electrical discontinuity in a first internal switch of the first block stop, and wherein detecting the second contact comprises detecting a second electrical discontinuity in a second internal switch of the second block stop.

20. The method of claim 18, wherein adjusting energization of the solenoid coil comprises adjusting a flow of current through the solenoid coil to translate the piston in the first direction within the piston cavity.

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