Compressor system, method of operating a compressor system, and computer storage medium
By employing parallel compressors and oil balance pipes in the compressor system, combined with alternating operation modes, the problem of insufficient lubricating oil was solved, the structure and control logic were simplified, costs were reduced, and the safety and reliability of the system were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- COPELAND CLIMATE TECN (SUZHOU) CO LTD
- Filing Date
- 2021-09-29
- Publication Date
- 2026-06-16
AI Technical Summary
The existing compressor system suffers from insufficient lubricating oil, which leads to complex structure, complex control logic, and high cost. Furthermore, the existing oil balancing measures are outdated and ineffective, which may result in component damage and reduced reliability.
The system employs a first and second compressor connected in parallel, with the oil sump always connected via an oil balance pipe. The automatic balancing of the lubricating oil is achieved by alternating operation of the compressors, eliminating the need for additional control valves and simplifying the structure and control logic.
It achieves effective lubricant balance, simplifies the structure and control logic of the compressor system, reduces costs, and improves system safety and reliability.
Smart Images
Figure CN115875245B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a compressor system comprising at least two compressors and a method for operating the compressor system. Background Technology
[0002] The content in this section only provides background information related to this invention and may not constitute prior art.
[0003] A compressor system consisting of two or more compressors connected in parallel is known. This system can utilize multiple compressors with relatively smaller cooling capacities to replace a single compressor with a larger cooling capacity to meet larger system capacity requirements, thereby reducing system costs and improving overall system efficiency. In this compressor system, one compressor may have good oil return capability, thus ensuring sufficient lubrication; while another compressor may have poor oil return capability, potentially leading to insufficient lubrication.
[0004] In some existing compressor systems, oil balancing measures are typically implemented only when a detection system detects insufficient lubricating oil in a compressor. This involves either returning more lubricating oil to the compressor or shutting it down to prevent damage to the compressor or the entire compressor system. These oil balancing measures include using additional oil distribution devices or pressure regulating devices to force more lubricating oil back to the compressor where insufficient lubricating oil is detected.
[0005] In these compressor systems, insufficient lubrication has already occurred, resulting in delayed oil balancing measures. This can lead to poor oil balancing performance and even damage to certain components or reduced reliability of the compressor system. Furthermore, the need for additional equipment complicates the compressor system's structure and control logic, thus increasing costs.
[0006] In some existing compressor systems, oil balancing measures have been proposed to be implemented during normal compressor operation. These compressor systems typically include at least three compressors. Taking a compressor system with three compressors as an example, the lubricating oil from the first compressor is forced to flow into the second compressor. After running for a period of time, the lubricating oil from the second compressor flows into the third compressor. After running for a period of time, the lubricating oil from the third compressor returns to the second compressor. After running for a period of time, the lubricating oil from the second compressor returns to the first compressor, and so on in a continuous cycle. It is evident that to achieve this cycle, multiple valves and other control components are required. Therefore, the structure and control logic of these compressor systems are very complex, and the efficiency of the compressor systems is relatively low. Summary of the Invention
[0007] In view of the above-mentioned problems of existing compressor systems, one object of the present invention is to provide a compressor system that has a simple structure and control logic, low cost, and can effectively balance the lubrication problem in each compressor.
[0008] Another object of the present invention is to provide a compressor system that can operate safely and reliably.
[0009] Another objective of this invention is to provide a method for operating a compressor system, which has simple control logic, is safe and reliable, and can effectively balance the lubricating oil in each compressor.
[0010] According to one aspect of the present invention, a compressor system is provided. The compressor system includes a first compressor, a second compressor, and an oil balance pipe. The first compressor and the second compressor are connected in parallel. The oil sump of the first compressor is always in communication with the oil sump of the second compressor via the oil balance pipe. The oil return capacity of the first compressor is greater than that of the second compressor. One of the first compressor and the second compressor is configured to operate alternately between a first mode and a second mode, wherein the first mode refers to a mode designed according to cooling or heating requirements, and the second mode refers to a mode that allows more lubricating oil to return to the second compressor compared to the first mode.
[0011] The compressor system of this application can prevent oil imbalance problems in advance, and does not require additional components to force oil balancing measures. Therefore, the compressor system has a simple structure and control logic, which simplifies the manufacturing and assembly process and significantly reduces costs.
[0012] In some implementations, the first compressor and the other of the second compressor are configured to operate in a single design mode.
[0013] In some implementations, the first compressor is a constant-speed compressor and the second compressor is a variable-frequency compressor.
[0014] In some embodiments, one of the first compressor and the second compressor is the constant-speed compressor. The first mode is a mode in which the constant-speed compressor operates at a designed constant speed, and the second mode is a mode in which the constant-speed compressor stops operating.
[0015] In some embodiments, one of the first compressor and the second compressor is the variable frequency compressor. The first mode is a mode in which the variable frequency compressor operates at the designed required speed, and the second mode is a mode in which the variable frequency compressor operates at a speed higher than the required speed.
[0016] In some embodiments, the compressor system further includes an oil level sensor and / or a speed sensor, wherein the oil level sensor is configured to sense the oil level of the second compressor, and the speed sensor is configured to sense the speed of the drive shaft of the second compressor.
[0017] In some embodiments, the compressor system further includes an air balance pipe configured to connect the space containing the oil sump within the housing of the first compressor with the space containing the oil sump within the housing of the second compressor.
[0018] According to another aspect of this disclosure, a method for operating a compressor system is provided. The compressor system includes a first compressor and a second compressor connected in parallel, and an oil balance pipe. The oil sump of the first compressor is always connected to the oil sump of the second compressor through the oil balance pipe. The oil return capacity of the first compressor is greater than that of the second compressor. The operating method includes: the first compressor alternately operating between a first mode and a second mode, wherein the first mode refers to a mode designed according to cooling or heating requirements, and the second mode refers to a mode that allows more lubricating oil to return to the second compressor compared to the first mode; the second compressor operates at the designed required speed.
[0019] The operation method of this compressor system has similar advantages to the compressor system described above.
[0020] In some embodiments, the first compressor is a constant-speed compressor, the first mode is a mode in which the constant-speed compressor operates at a designed constant speed, and the second mode is a mode in which the constant-speed compressor stops operating. In some embodiments, the first compressor is a variable-frequency compressor, the first mode is a mode in which the variable-frequency compressor operates at a designed required speed, and the second mode is a mode in which the variable-frequency compressor operates at a speed higher than the required speed.
[0021] In some embodiments, the operating method further includes: monitoring the rotational speed of the drive shaft of the second compressor; and switching the first compressor to the second mode after the rotational speed of the second compressor is lower than a predetermined speed for a predetermined time.
[0022] In some embodiments, the operating method further includes: after switching to the second mode and when it is detected that the speed of the second compressor is not lower than the predetermined speed, resuming the first compressor to alternate between the second mode and the first mode.
[0023] In some embodiments, the operating method further includes: monitoring the oil level of the second compressor; and switching the first compressor to the second mode when the oil level of the second compressor is lower than a predetermined oil level.
[0024] In some embodiments, the operating method further includes: after switching to the second mode and when it is detected that the oil level of the second compressor is not lower than the predetermined oil level, causing the first compressor to resume alternating operation between the second mode and the first mode.
[0025] According to another aspect of this disclosure, a method for operating a compressor system is provided. The compressor system includes a first compressor and a second compressor connected in parallel, and an oil balance pipe. The oil sump of the first compressor is always connected to the oil sump of the second compressor through the oil balance pipe. The oil return capacity of the first compressor is greater than that of the second compressor. The operating method includes: the first compressor operating at a designed required speed; and the second compressor operating alternately between a first mode and a second mode, wherein the first mode refers to a mode designed according to cooling or heating requirements, and the second mode refers to a mode that allows more lubricating oil to return to the second compressor compared to the first mode.
[0026] The operation method of this compressor system has similar advantages to the compressor system described above.
[0027] In some embodiments, the second compressor is a constant-speed compressor. The first mode is a mode in which the constant-speed compressor operates at a designed constant speed, and the second mode is a mode in which the constant-speed compressor stops operating.
[0028] In some embodiments, the second compressor is a variable frequency compressor. The first mode is the mode in which the variable frequency compressor operates at the designed required speed, and the second mode is the mode in which the variable frequency compressor operates at a speed higher than the required speed.
[0029] In some embodiments, the operating method further includes: monitoring the rotational speed of the drive shaft of the second compressor; and switching the second compressor to the second mode after the rotational speed of the variable frequency compressor is lower than a predetermined speed for a predetermined time.
[0030] In some embodiments, the operating method further includes: after switching to the second mode and when it is detected that the speed of the variable frequency compressor is not lower than the predetermined speed, causing the second compressor to resume alternating operation between the second mode and the first mode.
[0031] In some embodiments, the operating method further includes: monitoring the oil level of the second compressor; and switching the second compressor to the second mode when the oil level of the second compressor is lower than a predetermined oil level.
[0032] In some embodiments, the operating method further includes: after switching to the second mode and when it is detected that the oil level of the second compressor is not lower than the predetermined oil level, causing the second compressor to resume alternating operation between the second mode and the first mode.
[0033] According to another aspect of this disclosure, a computer storage medium is also provided, wherein the computer storage medium stores a program that, when executed, implements the steps of the method described above.
[0034] Other application areas will become apparent from the description provided herein. It should be understood that the specific examples and implementations described in this section are for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description
[0035] The features and advantages of one or more embodiments of this disclosure will become more readily understood from the following description with reference to the accompanying drawings, in which:
[0036] Figure 1 This is a schematic diagram of a compressor system according to an embodiment of the present disclosure;
[0037] Figure 2 This is a flowchart illustrating the operation method of a compressor system according to an embodiment of the present disclosure;
[0038] Figure 3 This is a flowchart illustrating an operation method of a compressor system according to another embodiment of the present disclosure; and
[0039] Figure 4A and Figure 4B This is a perspective view of a compressor system according to another embodiment of the present disclosure.
[0040] It should be understood that in all these figures, the corresponding reference numerals indicate similar or corresponding parts and features. Detailed Implementation
[0041] Exemplary embodiments of this application will now be described more fully with reference to the accompanying drawings.
[0042] Exemplary embodiments are provided to make this disclosure exhaustive and to convey the scope more fully to those skilled in the art. Numerous specific details, such as examples of specific components, apparatuses, and methods, are set forth to provide a thorough understanding of various embodiments of this disclosure. It will be apparent to those skilled in the art that specific details are not required, that exemplary embodiments may be implemented in many different forms, and should not be construed as limiting the scope of this disclosure. In some exemplary embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
[0043] The following will be referred to Figure 1 A schematic diagram illustrating a compressor system 1 according to an embodiment of the present disclosure is provided. Figure 1 As shown, the compressor system 1 includes a first compressor 10 and a second compressor 20. The first compressor 10 and the second compressor 20 are connected in parallel.
[0044] The first compressor 10 includes a compressor body 12, an intake pipe 11 connected to the compressor body 12, and an exhaust pipe 13. A working fluid (e.g., refrigerant) enters the compressor body 12 via the intake pipe 11, is compressed, and then exits from the exhaust pipe 13 and enters other components of the compressor system 1 (e.g., a heat exchanger serving as a condenser) (not shown).
[0045] The second compressor 20 includes a compressor body 22, an intake pipe 21 connected to the compressor body 22, and an exhaust pipe 23. The working fluid enters the compressor body 22 via the intake pipe 21, is compressed, and then discharged from the exhaust pipe 23 and enters other components of the compressor system 1 (e.g., a heat exchanger as a condenser) (not shown).
[0046] The intake pipe 11 of the first compressor 10 and the intake pipe 21 of the second compressor 20 are connected to the intake manifold 40. Low-temperature and low-pressure working fluid flows from the intake manifold 40 into the intake pipe 11 and the intake pipe 21 respectively, and then enters the first compressor body 12 and the second compressor body 22 respectively.
[0047] The exhaust pipe 13 of the first compressor 10 and the exhaust pipe 23 of the second compressor 20 are connected to the exhaust manifold 30. The high-temperature and high-pressure working fluid after compression is discharged to the exhaust manifold 30 through the exhaust pipe 13 and the exhaust pipe 23, respectively, and then discharged into the compressor system 1 through the exhaust manifold 30.
[0048] The intake pipe 11 of the first compressor 10 is connected to the intake pipe 21 of the second compressor 20, and the exhaust pipe 13 of the first compressor 10 is connected to the exhaust pipe 23 of the second compressor 20. Therefore, the first compressor 10 and the second compressor 20 are connected in parallel.
[0049] The compressor system 1 also includes an oil balance pipe 50. The oil balance pipe 50 is configured to connect the oil sump of the first compressor 10 (e.g., the bottom of the compressor body 12) to the oil sump of the second compressor 20 (e.g., the bottom of the compressor body 22). The compressor system 1 according to this disclosure does not include a valve on the oil balance pipe 50 for forcibly controlling its opening and closing. That is, the oil balance pipe 50 keeps the oil sump of the first compressor 10 always connected to the oil sump of the second compressor 20. Therefore, such an oil balance pipe 50 automatically achieves oil balance between the two compressors through the operation of the compressor system 1. Since control elements such as valves can be eliminated, the number of parts can be significantly reduced, the manufacturing and assembly process simplified, and thus costs can be significantly reduced. Furthermore, the size (diameter) of the oil balance pipe 50 can be reduced, thus further reducing costs.
[0050] During the operation of compressor system 1, lubricating oil circulates within the compressor system 1 along with the working fluid. When the working fluid entering the compressor body 12 or 22 via intake pipe 11 or 21 contains less lubricating oil than the working fluid exiting via exhaust pipe 13 or 23, the oil level in the oil sump of compressor 10 or 20 will gradually decrease, eventually leading to insufficient lubrication. Consequently, moving parts will wear or even fail prematurely. The term "oil return capacity" is commonly used to reflect the ability to return lubricating oil to the compressor. In other words, during the operation of the compressor system, if one of the compressors can return more lubricating oil to its oil sump, that compressor has a better or higher oil return capacity.
[0051] Compressor system 1 typically includes at least two compressors. Due to differences in compressor type or operating parameters, the distribution of working fluid varies, resulting in different oil return capabilities. For example, a compressor system might include one variable-frequency compressor and one fixed-speed compressor. The variable-frequency compressor often has a smaller cooling capacity than the fixed-speed compressor, leading to higher oil pressure within the variable-frequency compressor. This pressure difference forces the lubricating oil from the variable-frequency compressor into the fixed-speed compressor. Under these circumstances, after the compressor system has been running for a period of time, the variable-frequency compressor will experience oil shortage, while the fixed-speed compressor will generally not. In this compressor system, the fixed-speed compressor has a better oil return capability than the variable-frequency compressor; that is, the fixed-speed compressor's oil return capability is greater than that of the variable-frequency compressor.
[0052] Given that the operation of each compressor may lead to an imbalance of lubricating oil, the inventors of this application propose to improve the structure and operation of the compressor, that is, to use a simple structure and control logic to effectively prevent and achieve oil balance between the compressors during the operation of the compressor system.
[0053] According to the compressor system 1 of this disclosure, one of the compressors (compressor 10 or compressor 20) is configured to operate (regularly) alternate between a first mode and a second mode. The first mode refers to a mode designed according to cooling or heating demand (i.e., a conventional mode), and the second mode refers to a mode that allows more lubricating oil to return to the compressor with poor oil return capacity compared to the first mode (i.e., an oil return mode).
[0054] The following will be referred to Figure 2 This is a flowchart illustrating the operation method 100 of the compressor system 1 according to an embodiment of the present disclosure.
[0055] Figure 2 This is a flowchart illustrating the operation method of a compressor system according to an embodiment of this disclosure. Figure 2 As shown, after compressor system 1 starts, each compressor initially operates in the first mode (normal mode) (step S110). The first mode operation lasts for a duration T1 (step S120). After the first mode operation time T1, due to oil imbalance between the compressors, the oil level in the oil sump of each compressor changes. The lubricating oil in the compressor with poor oil return capability gradually decreases. At this time, one compressor in compressor system 1 is switched to the second mode (oil return mode) (step S130). During the second mode, more lubricating oil is returned to the compressor with poor oil return capability. The second mode operation lasts for a duration T2 (step S140). After the second mode operation time T2, the oil level in the compressor with poor oil return capability recovers, for example, reaching approximately the initial level. At this time, each compressor in compressor system 1 can be switched back to the first mode (step S110), and this cycle continues.
[0056] according to Figure 2 The operating method shown can prevent oil shortage in advance with a simple structure and control logic. The compressor system 1 according to this disclosure has fewer parts, simplifies manufacturing and assembly, reduces costs, and can effectively prevent oil imbalance problems.
[0057] It is possible to Figure 1 The first compressor 10 is a fixed-speed compressor and the second compressor 20 is a variable-frequency compressor, which are used as examples to describe in detail the operation method 100 of the compressor system according to an embodiment of the present disclosure. The oil return capacity of the first compressor 10 is generally better than that of the second compressor 20.
[0058] In one example, oil balance can be achieved by configuring or controlling the operating mode of the first compressor (constant speed compressor) 10.
[0059] Combination Figure 2In step S110, the first compressor 10 can be operated in a constant speed mode (first mode), that is, at a designed constant speed. During this period, the second compressor 20 operates at the required speed in its normal mode or design mode. Because the first compressor 10 has better oil return capability, its oil level gradually rises, while the second compressor 20 has poorer oil return capability, so its oil level gradually falls.
[0060] After a running time T1, the first compressor 10 is stopped, i.e., in shutdown mode (second mode). At this time, the second compressor 20 continues to operate at the required speed in its normal or design mode. Therefore, the oil sump pressure of the first compressor 10 is greater than that of the second compressor 20. Under the influence of this pressure difference, the lubricating oil in the first compressor 10 flows into the second compressor 20 through the oil balance pipe 50, thereby preventing or alleviating the problem of insufficient lubricating oil in the second compressor 20.
[0061] In this example, the second compressor (inverter compressor) 20 always operates in conventional mode or design mode, while the first compressor (constant speed compressor) 10 operates (regularly) alternating between constant speed mode (first mode) and shutdown mode (second mode).
[0062] In another example, oil balance can be achieved by configuring or controlling the operating mode of the second compressor (variable frequency compressor) 20.
[0063] Combination Figure 2 In step S110, the second compressor 20 can be operated in either a conventional mode or a design mode (first mode), that is, operating at a designed variable speed according to the operating conditions. During this period, the first compressor 10 operates in a constant speed mode (conventional mode or design mode). Because the first compressor 10 has better oil return capability, its oil level gradually increases, while the second compressor 20 has poorer oil return capability, so its oil level gradually decreases.
[0064] After a running time T1, the second compressor 20 is switched to a second mode with a predetermined high speed. At this time, the first compressor 10 still operates in constant speed mode. The predetermined high speed of the second compressor 20 in the second mode is greater than the corresponding design speed (required speed or normal speed) of the first mode. Thus, the first mode can also be called the low-frequency mode, and the second mode the high-frequency mode. Therefore, when the second compressor 20 operates in the second mode, more lubricating oil can return to the second compressor 20, thereby preventing or mitigating oil imbalance problems.
[0065] In this example, the first compressor (constant speed compressor) 10 always operates in constant speed mode, while the second compressor (variable frequency compressor) 20 operates (regularly) alternating between low frequency mode (first mode) and high frequency mode (second mode).
[0066] In addition to the aforementioned measures to prevent oil imbalance, the compressor system 1 according to this disclosure can also be equipped with, for example, a sensing device to sense or determine the oil level of a compressor with poor oil return capability. See below. Figure 3 This describes the operation method of the compressor system in this embodiment when the oil level is detected to be low.
[0067] Figure 3 This is a schematic flowchart of a compressor system operation method 300 according to another embodiment of the present disclosure. Figure 3 The operating method 300 shown combines the preventive measures of the above-mentioned operating method 100 with the remedial measures when the oil level is low.
[0068] like Figure 3 As shown, during the above-described operation method 100, it is also sensed or determined whether the oil level of the compressor with poor oil return will fall below a predetermined oil level (step S310). If it is sensed or determined that the oil level of the compressor will not fall below the predetermined oil level, the above-described operation method 100 continues to be executed. When it is sensed or determined that the oil level of the compressor with poor oil return will fall below the predetermined oil level, one of the compressors is switched to the second mode (step S320). During the second mode, more lubricating oil is returned to the compressor with poor oil return and insufficient oil. The second mode is operated for a duration T (step S330). The time T can be the same as the time T2 in the above-described operation method 100, or it can be longer than the time T2 to ensure that more lubricating oil is returned and the oil shortage problem can be solved.
[0069] After running in the second mode for a time T, if it is still sensed or determined that the oil level of the compressor with poor oil return will be lower than the predetermined oil level, then step S320 is executed, that is, the second mode is continued.
[0070] After operating in the second mode for a time T, the oil level in the compressor with poor oil return capacity rises. At this time, if there is no sensing or judgment that the oil level of the compressor with poor oil return will fall below the predetermined oil level, the compressor system 1 can continue to operate according to the above-described operating method 100, that is, to make one of the compressors alternate between the first mode and the second mode.
[0071] Similarly, the following describes in detail the operation method 300 of the compressor system according to an embodiment of the present disclosure, using the example of a first compressor 10 being a fixed-speed compressor and a second compressor 20 being a variable-frequency compressor. The oil return capacity of the first compressor 10 is superior to that of the second compressor 20.
[0072] In one example, an oil level sensor is provided for sensing the oil level of the second compressor (inverter compressor) 20, and oil balance is achieved by configuring or controlling the operating mode of the first compressor (constant speed compressor) 10.
[0073] Combination Figure 3 In step S310, an oil level sensor detects whether the oil level in the second compressor 20 is lower than a predetermined oil level. If no lower-than-predetermined lower-than-predetermined oil level is detected in the second compressor 20, the above-described operation method 100 continues. When the lower-than-predetermined lower-than-predetermined oil level is detected in the second compressor 20, in step S320, the first compressor 10 is stopped, i.e., switched to a shutdown mode (second mode). At this time, the second compressor 20 still operates at the required speed in its normal mode or design mode. Therefore, the oil sump pressure in the first compressor 10 is greater than that in the second compressor 20. Under the action of the pressure difference, the lubricating oil in the first compressor 10 flows into the second compressor 20 through the oil balance pipe 50, thereby alleviating the problem of insufficient lubricating oil in the second compressor 20.
[0074] After the first compressor 10 has stopped operating for a duration T, if the oil level of the second compressor 20 is still lower than the predetermined oil level, the first compressor 10 continues to execute step S320, that is, continues to operate in shutdown mode.
[0075] After the first compressor 10 stops operating for a duration T, causing the oil level to rise above a predetermined oil level, the first compressor 10 can resume operating method 100, that is, continue to operate alternately between the first mode and the second mode.
[0076] In another example, an oil level sensor is provided for sensing the oil level of the second compressor (inverter compressor) 20, and oil balance is achieved by configuring or controlling the operating mode of the second compressor (inverter compressor) 20.
[0077] Combination Figure 3 In step S310, an oil level sensor is used to detect whether the oil level in the second compressor 20 is lower than a predetermined oil level. If no lower-than-predetermined lower-than-predetermined oil level is detected in the second compressor 20, the above-described operating method 100 continues. When the lower-than-predetermined lower-than-predetermined oil level is detected in the second compressor 20, in step S320, the second compressor 20 is switched to frequency-increase mode (second mode). At this time, the first compressor 10 still operates in constant-speed mode. Operating the second compressor 20 in frequency-increase mode allows more lubricating oil to return to the second compressor 20, thereby alleviating the oil imbalance problem.
[0078] After the second compressor 20 has been running in frequency-increase mode for a duration T, if the oil level of the second compressor 20 is still lower than the predetermined oil level, the second compressor 20 continues to execute step S320, that is, continues to run in frequency-increase mode.
[0079] After the second compressor 20 operates in frequency-increasing mode for a duration T, causing the oil level to rise above a predetermined oil level, the second compressor 20 can resume operating method 100, that is, continue to operate alternately between the first mode (low-frequency mode) and the second mode (high-frequency mode).
[0080] In another example, a speed sensor is provided for sensing the rotational speed of the drive shaft of the second compressor (variable frequency compressor) 20, and oil balance is achieved by configuring or controlling the operating mode of the first compressor (constant speed compressor) 10.
[0081] Combination Figure 3 In step S310, a speed sensor is used to sense whether the speed of the second compressor 20 is lower than a predetermined speed. If no speed lower than the predetermined speed is detected, the above-described operation method 100 continues. If the speed of the second compressor 20 is detected to be lower than the predetermined speed for a predetermined time, it is determined that the oil return of the second compressor 20 is insufficient, which may lead to insufficient lubricating oil. Therefore, in step S320, the first compressor 10 is stopped, that is, switched to the shutdown mode (second mode). At this time, the second compressor 20 still operates at the required speed in its normal mode or design mode. Therefore, the oil sump pressure of the first compressor 10 is greater than the oil sump pressure of the second compressor 20. Under the action of the pressure difference, the lubricating oil in the first compressor 10 flows into the second compressor 20 through the oil balance pipe 50, thereby alleviating the problem of insufficient lubricating oil in the second compressor 20.
[0082] After the first compressor 10 has stopped operating for a duration T, if the speed of the second compressor 20 is still lower than the predetermined speed, the first compressor 10 continues to execute step S320, that is, continues to operate in the shutdown mode.
[0083] When the first compressor 10 stops operating for a duration T and the speed of the second compressor 20 is higher than a predetermined speed, the first compressor 10 can resume operating method 100, that is, continue to operate alternately between the first mode and the second mode.
[0084] In another example, a speed sensor is provided for sensing the rotational speed of the drive shaft of the second compressor (inverter compressor) 20, and oil balance is achieved by configuring or controlling the operating mode of the second compressor (inverter compressor) 20.
[0085] Combination Figure 3In step S310, a speed sensor is used to sense whether the speed of the second compressor 20 is lower than a predetermined speed. If no speed lower than the predetermined speed is detected, the above-described operation method 100 continues. If the speed of the second compressor 20 is detected to be lower than the predetermined speed for a predetermined time, it is determined that the oil return of the second compressor 20 is insufficient, which may lead to insufficient lubricating oil. Therefore, in step S320, the second compressor 20 is switched to frequency-increase mode (second mode). At this time, the first compressor 10 still operates in constant speed mode. The second compressor 20 operating in frequency-increase mode allows more lubricating oil to return to the second compressor 20, thereby alleviating the oil imbalance problem.
[0086] After the second compressor 20 has been running in frequency-increase mode for a duration T, if the speed of the second compressor 20 is still lower than the predetermined speed, the second compressor 20 continues to execute step S320, that is, continues to run in frequency-increase mode.
[0087] When the second compressor 20 operates in frequency-increasing mode for a duration T and the speed is higher than the predetermined speed, the second compressor 20 can resume the operation method 100, that is, continue to operate alternately between the first mode (low-frequency mode) and the second mode (high-frequency mode).
[0088] Figure 4A and Figure 4B This is a perspective view of a compressor system 2 according to another embodiment of the present disclosure from a different angle. Figure 4A and Figure 4B The compressor system 2 shown is Figure 1 The compressor system 1 shown is different in that it also includes a gas balance pipe 70 and a jet enthalpy-increasing pipe 60.
[0089] The vapor injection enthalpy enhancer 60 is configured to introduce the working fluid from the compressor system 2 into a compression chamber to improve compressor performance. The vapor injection enthalpy enhancer 60 is similar to the vapor injection enthalpy enhancer found in conventional compressors, and therefore will not be described in detail herein.
[0090] The gas balance pipe 70 is configured to connect the space containing the oil sump inside the housing of the first compressor 10 and the space containing the oil sump inside the housing of the second compressor 20. The gas balance pipe 70 can make the fluid pressure in the low-pressure space (also called the intake space or oil sump space) of the housing of the first compressor 10 and the low-pressure space (also called the intake space or oil sump space) of the housing of the second compressor 20 reach a certain degree of balance.
[0091] For example, the cooling / heating capacity of the first compressor 10 is higher than that of the second compressor 20, therefore the oil return capacity of the first compressor 10 is better than that of the second compressor 20. When the first compressor 10 and the second compressor 20 operate simultaneously, the fluid pressure in the low-pressure space of the first compressor 10's housing will be lower than that in the low-pressure space of the second compressor 20's housing, which is not conducive to the return of lubricating oil in the first compressor 10 to the second compressor 20. Therefore, by providing the air balance pipe 70, the pressure difference between the low-pressure spaces of the first compressor 10 and the second compressor 20's housings can be alleviated or reduced, thereby alleviating or reducing the oil imbalance problem between the first compressor 10 and the second compressor 20.
[0092] According to this disclosure, a computer storage medium is also provided. The computer storage medium stores a program that, when executed, implements the steps of the method described above.
[0093] It should be noted that the compressors in the embodiments of this application may include, but are not limited to, variable capacity compressors, variable frequency compressors, horizontal compressors, or high-pressure side compressors. Furthermore, in the above embodiments, each compressor may be selected from groups consisting of free piston compressors, rotary compressors, screw compressors, centrifugal compressors, etc. Additionally, the compressors may be of the same type or different types to achieve a more flexible system arrangement.
[0094] Although various embodiments of the invention have been described in detail herein, it should be understood that the invention is not limited to the specific embodiments described and shown herein, and other variations and modifications can be made by those skilled in the art without departing from the essential spirit and scope of the invention. All such variations and modifications fall within the scope of the invention.
Claims
1. A compressor system, comprising: First compressor (10); The second compressor (20) is connected in parallel with the first compressor; as well as Oil balance pipe (50), the oil sump of the first compressor is always connected to the oil sump of the second compressor through the oil balance pipe. in, The oil return capacity of the first compressor is greater than that of the second compressor; One of the first compressor and the second compressor is configured to operate alternately between a first mode and a second mode, wherein the first mode refers to a mode designed according to cooling or heating needs, and the second mode refers to a mode that allows more lubricating oil to return to the second compressor compared to the first mode.
2. The compressor system according to claim 1, wherein, The first compressor and the other of the second compressor are configured to operate in a single design mode.
3. The compressor system according to claim 1, wherein, The first compressor is a fixed-speed compressor, and the second compressor is a variable-frequency compressor.
4. The compressor system according to claim 3, wherein, One of the first compressor and the second compressor is the constant-speed compressor. The first mode is the mode in which the constant-speed compressor operates at a designed constant speed; The second mode is the mode in which the constant-speed compressor stops running.
5. The compressor system according to claim 3, wherein, One of the first compressor and the second compressor is the variable frequency compressor. The first mode is the mode in which the variable frequency compressor operates at the designed required speed; The second mode is when the variable frequency compressor operates at a speed higher than the required speed.
6. The compressor system according to any one of claims 1 to 5, wherein, The compressor system further includes an oil level sensor and / or a speed sensor, wherein the oil level sensor is configured to sense the oil level of the second compressor, and the speed sensor is configured to sense the speed of the drive shaft of the second compressor.
7. The compressor system according to any one of claims 1 to 5, wherein, The compressor system also includes an air balance pipe (70) configured to connect the space where the oil sump is located inside the housing of the first compressor with the space where the oil sump is located inside the housing of the second compressor.
8. A method for operating a compressor system, wherein, The compressor system includes a first compressor and a second compressor connected in parallel, as well as an oil balance pipe. The oil sump of the first compressor is always connected to the oil sump of the second compressor through the oil balance pipe. The oil return capacity of the first compressor is greater than that of the second compressor. The operating method includes: The first compressor operates alternately between a first mode and a second mode, wherein the first mode refers to a mode designed according to cooling or heating requirements, and the second mode refers to a mode that allows more lubricating oil to return to the second compressor compared to the first mode; and The second compressor operates at the designed required speed.
9. The method for operating the compressor system according to claim 8, wherein, The first compressor is a constant-speed compressor, the first mode is the mode in which the constant-speed compressor operates at a designed constant speed, and the second mode is the mode in which the constant-speed compressor stops operating; or The first compressor is a variable frequency compressor, the first mode is the mode in which the variable frequency compressor operates at the designed required speed, and the second mode is the mode in which the variable frequency compressor operates at a speed higher than the required speed.
10. The method of operating the compressor system according to claim 8 or 9, further comprising: Monitor the rotational speed of the drive shaft of the second compressor; as well as After the second compressor operates at a speed lower than a predetermined speed for a predetermined period of time, the first compressor is switched to the second mode.
11. The method for operating the compressor system according to claim 10, further comprising: After switching to the second mode and when it is detected that the speed of the second compressor is not lower than the predetermined speed, the first compressor is restored to alternating operation between the second mode and the first mode.
12. The method of operating the compressor system according to claim 8 or 9, further comprising: Monitor the oil level in the second compressor; as well as When the oil level in the second compressor is lower than the predetermined oil level, the first compressor is switched to the second mode.
13. The method for operating the compressor system according to claim 12, wherein, Also includes: After switching to the second mode and when it is detected that the oil level of the second compressor is not lower than the predetermined oil level, the first compressor is restored to alternating operation between the second mode and the first mode.
14. A method for operating a compressor system, wherein, The compressor system includes a first compressor and a second compressor connected in parallel, as well as an oil balance pipe. The oil sump of the first compressor is always connected to the oil sump of the second compressor through the oil balance pipe. The oil return capacity of the first compressor is greater than that of the second compressor. The operating method includes: The first compressor operates at the designed required speed; and The second compressor operates alternately between a first mode and a second mode, wherein the first mode refers to a mode designed according to cooling or heating needs, and the second mode refers to a mode that allows more lubricating oil to return to the second compressor compared to the first mode.
15. The method of operating the compressor system according to claim 14, wherein, The second compressor is a constant-speed compressor. The first mode is the mode in which the constant-speed compressor operates at a designed constant speed; The second mode is the mode in which the constant-speed compressor stops running.
16. The method of operating the compressor system according to claim 14, wherein, The second compressor is a variable frequency compressor. The first mode is the mode in which the variable frequency compressor operates at the designed required speed; The second mode is when the variable frequency compressor operates at a speed higher than the required speed.
17. The method of operating the compressor system according to claim 14 or 16, further comprising: Monitor the rotational speed of the drive shaft of the second compressor; as well as After the second compressor operates at a speed lower than a predetermined speed for a predetermined period of time, the second compressor is switched to the second mode.
18. The method of operating the compressor system according to claim 17, further comprising: After switching to the second mode and when it is detected that the speed of the second compressor is not lower than the predetermined speed, the second compressor is restored to alternating operation between the second mode and the first mode.
19. The method of operating the compressor system according to any one of claims 14 to 16, further comprising: Monitor the oil level in the second compressor; as well as When the oil level in the second compressor is lower than the predetermined oil level, the second compressor is switched to the second mode.
20. The method of operating the compressor system according to claim 19, wherein, Also includes: After switching to the second mode and when it is detected that the oil level of the second compressor is not lower than the predetermined oil level, the second compressor is restored to alternating operation between the second mode and the first mode.
21. A computer storage medium, wherein, The computer storage medium stores a program that, when executed, performs the steps of the method as described in any one of claims 8-20.