Parallel compressor set refrigeration system with gas-liquid equilibrium function

Abstract

The utility model discloses a kind of parallel compressor unit refrigeration systems with gas-liquid balance function, including multiple parallel refrigeration units, and refrigeration unit includes multiple parallel compressors.Oil separation component is used to separate high-pressure gaseous refrigerant and liquid lubricating oil discharged by compressor, and separated lubricating oil is transported to compressor by first pipeline, and separated refrigerant is transported to condenser by second pipeline.Liquid phase balance pipeline is communicated with multiple first pipelines respectively, to make the liquid level of lubricating oil in multiple oil separation components consistent.By setting oil separation component in refrigeration unit, for supplying oil to multiple compressors, while setting liquid phase and gas phase balance pipeline respectively with first pipeline and second pipeline in each refrigeration unit, the liquid level and air pressure of lubricating oil in multiple oil separation components are kept consistent.In this way, lubricating oil in the entire refrigeration system can flow across unit, so as to ensure the stability of oil supply in the entire refrigeration system.

Description

Technical Field

[0001] This application relates to the field of refrigeration equipment technology, and in particular to a parallel compressor unit refrigeration system with gas-liquid balance function. Background Technology

[0002] Multiple parallel refrigeration units form a unified refrigeration system by connecting multiple refrigeration units through piping, control systems, etc., and are commonly used in medium and large-scale refrigeration scenarios (such as large cold storage facilities and industrial refrigeration workshops). Multiple parallel refrigeration units can meet the cooling needs of high loads through the coordinated operation of multiple refrigeration units.

[0003] In related technologies, oil separators are installed within multiple parallel compressors to separate lubricating oil and refrigerant. Additionally, external oil reservoirs are installed around the compressors to supply oil to all of them simultaneously, ensuring a balanced oil supply to each compressor by providing the same oil pressure. However, since the external oil reservoir is the sole oil storage device, leaks or malfunctions in the oil level protection device can lead to a simultaneous interruption of oil supply to all parallel compressors. Utility Model Content

[0004] This utility model discloses a parallel compressor unit refrigeration system with gas-liquid balance function, which can help improve the oil supply stability of multiple refrigeration units in the refrigeration system.

[0005] To achieve the above objectives, the first aspect of this utility model discloses a parallel compressor unit refrigeration system with gas-liquid balance function, comprising:

[0006] Multiple refrigeration units connected in parallel, the refrigeration units including:

[0007] Evaporator;

[0008] A condenser, which is connected to the evaporator via a pipe, to deliver liquid refrigerant to the evaporator;

[0009] Multiple compressors are connected in parallel, and the compressors are connected to the evaporator through pipes to receive gaseous refrigerant delivered by the evaporator;

[0010] An oil separation assembly is provided with a first inlet, a first outlet, and a second outlet. The first inlet is located near the top of the oil separation assembly and is connected to multiple compressors via pipelines. The first inlet is used to receive high-pressure gaseous refrigerant and liquid lubricating oil discharged from the compressors. The oil separation assembly is configured to separate the refrigerant and lubricating oil. The first outlet is located at the bottom of the oil separation assembly and is connected to the compressors via a first pipeline to return the lubricating oil to the compressors. The second outlet is located at the top of the oil separation assembly and is connected to the condenser via a second pipeline to deliver gaseous refrigerant to the condenser.

[0011] A liquid phase balance pipeline is connected to the first pipeline in each of the refrigeration units. The liquid phase balance pipeline is configured to allow lubricating oil to flow between the multiple oil separation components so that the lubricating oil level in the multiple oil separation components remains consistent.

[0012] A gas phase balancing pipeline is connected to the second pipeline in each of the refrigeration units. The gas phase balancing pipeline is configured to allow gaseous refrigerant to flow between the multiple oil separation components so that the gas pressure in the multiple oil separation components remains consistent.

[0013] As an optional implementation, the oil separation assembly is provided with a liquid level detection element and an alarm, wherein the liquid level detection element is configured to detect the liquid level height of the lubricating oil in the oil separation assembly;

[0014] A control device is electrically connected to both the liquid level detection element and the alarm. The control device is configured to control the alarm to sound when the liquid level detection element detects that the level of the lubricating oil is at a first preset level.

[0015] As an optional implementation, the refrigeration unit further includes a gas-liquid balance pipeline, which is connected to each of the oil separation components. A first solenoid valve is provided on the gas-liquid balance pipeline, and the control device is electrically connected to the first solenoid valve. The control device is also configured to control the first solenoid valve to open when the level detection element detects that the level of the lubricating oil is at a second preset level, so as to keep the lubricating oil level and gas pressure in the multiple oil separation components consistent.

[0016] Wherein, the first preset oil level is lower than the second preset oil level.

[0017] As an optional implementation, the oil separation assembly is provided with a heating element at the bottom, which is configured to heat the lubricating oil inside the oil separation assembly.

[0018] As an optional implementation, the oil separation assembly includes an oil separator and a heat exchanger, wherein the oil separator is provided with a first inlet, a first outlet and a second outlet;

[0019] The heat exchanger is provided with a second inlet and a third outlet that are arranged opposite to each other along the height direction of the oil separator. The second inlet is located at the top of the heat exchanger, and the third outlet is located at the bottom of the heat exchanger. The second inlet and the third outlet are connected by a third pipeline.

[0020] The first pipeline includes a first sub-pipeline and a second sub-pipeline. The second inlet is connected to the first outlet through the first sub-pipeline to send lubricating oil into the heat exchanger for heat exchange. The third outlet is connected to the lubricating oil inlet of the compressor through the second sub-pipeline to send the heat-exchanged lubricating oil into the corresponding compressor.

[0021] As an alternative implementation, a filter device is provided on the first sub-pipeline, the filter device being configured to filter the lubricating oil.

[0022] As an optional implementation, the compressor is provided with a detection element configured to detect the start and stop of the compressor, and a second solenoid valve is provided on the second sub-pipeline for controlling the connection between the second sub-pipeline and the third outlet;

[0023] The parallel compressor unit refrigeration system with gas-liquid balance function also includes a control device, which is electrically connected to the detection element and the solenoid valve. The control device is configured to control the solenoid valve to start or close according to the detection result of the detection element.

[0024] As an optional implementation, the refrigeration unit further includes a siphon liquid receiver, which has a first gas-liquid mixing inlet, a second gas-liquid mixing inlet, a first liquid outlet, a second liquid outlet, and a gas outlet. The first gas-liquid mixing inlet and the gas outlet are both connected to the condenser through pipes to condense the gaseous refrigerant into a gas-liquid mixed refrigerant. The first liquid outlet is connected to the evaporator through a pipe to deliver the liquid refrigerant to the evaporator. The second gas-liquid mixing inlet and the second liquid outlet are both connected to the heat exchanger to deliver the liquid refrigerant into the evaporator for heat exchange.

[0025] As an optional implementation, the siphon reservoir is provided with a partition, which divides the interior of the siphon reservoir into an interconnected siphon space and a storage space. The first gas-liquid mixing inlet, the second gas-liquid mixing inlet, and the second liquid outlet are all located in the siphon space, the first liquid outlet is located in the storage space, and the second liquid outlet is located above the first liquid outlet.

[0026] As an optional implementation, the partition is provided with a drain pipe, which is connected to the liquid storage space. The drain pipe has a drain outlet, and the refrigerant in the siphon space can enter the drain pipe through the drain outlet to enter the liquid storage space.

[0027] Compared with the prior art, the beneficial effects of this application are:

[0028] This utility model provides a parallel compressor unit refrigeration system with gas-liquid balance function, comprising multiple parallel refrigeration units. Each refrigeration unit includes multiple compressors connected in parallel. All compressors are connected to the first inlet of an oil separator assembly via pipelines to transport the high-pressure gaseous refrigerant and liquid lubricating oil discharged from the compressors to the oil separator assembly for gas-liquid separation. The separated gaseous refrigerant returns to the compressor via a second pipeline, passing sequentially through a condenser and an evaporator. The separated lubricating oil is returned to the compressor via a first pipeline. Additionally, liquid phase balance pipelines are connected to the first pipelines within each refrigeration unit, allowing lubricating oil to flow between the multiple oil separator assemblies to maintain a consistent lubricating oil level. Gas phase balance pipelines are connected to the second pipelines within each refrigeration unit, allowing gaseous refrigerant to flow between the multiple oil separator assemblies to maintain a consistent gas pressure. By installing oil separators within each refrigeration unit to store lubricating oil supplied by multiple compressors within the unit, and connecting the first and second pipelines within each unit via liquid-phase and gas-phase balance pipelines, the lubricating oil stored in each oil separator can flow across units. This ensures flexible lubricating oil supply based on the actual needs of each refrigeration unit, thus resolving the oil imbalance problem within the parallel compressor refrigeration system with gas-liquid balance functionality. The gas-phase balance pipelines maintain consistent gas pressure within the multiple oil separators, preventing uneven refrigerant circulation due to pressure differences and indirectly ensuring stable oil supply. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a parallel compressor unit refrigeration system with gas-liquid balance function disclosed in the embodiments of this application;

[0031] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle;

[0032] Figure 3 yes Figure 1 A magnified view of a section at point B in the middle;

[0033] Figure 4 This is a schematic diagram of the siphon reservoir disclosed in the embodiments of this application.

[0034] Explanation of reference numerals in the attached figures:

[0035] 100 - Parallel compressor unit refrigeration system with gas-liquid balance function; 101 - Refrigeration unit; 1 - Evaporator; 2 - Condenser; 21 - Second pipeline; 3 - Compressor; 31 - First pipeline; 311 - First sub-pipeline; 311a - Filter device; 312 - Second sub-pipeline; 312a - Second solenoid valve; 4 - Oil separation assembly; 41 - Oil separator; 411 - First inlet; 412 - First outlet; 413 - Second outlet; 414 - Liquid level detection element; 415 - Alarm; 416 - Heating element; 42 - Heat exchanger ; 421-Second inlet; 422-Third outlet; 422a-Third pipeline; 5-Siphon reservoir; 51-Baffle; 511-Drain pipe; 511a-Drain outlet; 52-Siphon space; 521-First gas-liquid mixing inlet; 522-Second gas-liquid mixing inlet; 523-Second liquid outlet; 524-Gas outlet; 53-Storage space; 531-First liquid outlet; 6-Expansion valve; 102-Liquid phase balance pipeline; 103-Gas phase balance pipeline; 104-Gas-liquid balance pipeline; 104a-First solenoid valve. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] In this application, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0038] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0039] Furthermore, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0040] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0041] A multi-parallel refrigeration unit is a refrigeration system that achieves centralized cooling by connecting multiple compressors (or complete refrigeration units) in parallel. This type of refrigeration system is widely used in large commercial buildings, industrial production, cold chain logistics, and other scenarios that require large cooling capacity or flexible adjustment of cooling capacity.

[0042] In a refrigeration system, the compressor's lubricating oil needs to mix with the refrigerant to participate in the circulation, and the flow of the lubricating oil depends entirely on the circulation power of the refrigerant. When multiple compressors are connected in parallel, the number of operating compressors and their load rates may differ, leading to differences in the discharge capacity of each compressor. This, in turn, results in different amounts of lubricating oil carried out with the refrigerant, making it difficult to distribute the lubricating oil evenly and affecting the stability of the oil supply to multiple refrigeration units within the refrigeration system.

[0043] In related technologies, oil separators are typically installed within multiple parallel compressors to separate lubricating oil and refrigerant. Additionally, external oil reservoirs are installed around the compressors to supply oil simultaneously, ensuring all compressors have the same oil supply pressure and thus guaranteeing balanced oil supply. However, as the sole oil storage device, the external oil reservoir is vulnerable to leaks or malfunctions such as oil level protection device failure, which could lead to a simultaneous interruption of oil supply to all parallel compressors.

[0044] In view of this, this application discloses a parallel compressor unit refrigeration system with gas-liquid balance function, including multiple parallel refrigeration units, each refrigeration unit including multiple parallel compressors, the compressors being connected to the evaporator via pipelines to receive gaseous refrigerant. An oil separation assembly is used to receive high-pressure gaseous refrigerant and liquid lubricating oil discharged from the compressors, then separates the refrigerant and lubricating oil. The separated lubricating oil is transported to the compressor through a first pipeline, and the separated refrigerant is transported to the condenser through a second pipeline. Liquid phase balance pipelines are connected to the first pipelines in each refrigeration unit to maintain a consistent lubricating oil level in the multiple oil separation assemblies. Gas phase balance pipelines are connected to the second pipelines in each refrigeration unit to maintain a consistent gas pressure in the multiple oil separation assemblies. By setting up oil separation assemblies within the refrigeration units to receive refrigerant and lubricating oil discharged from all compressors within the refrigeration units, the separated lubricating oil is transported back to each compressor through the first pipeline, and the separated refrigerant is transported back to each compressor through the second pipeline. Simultaneously, liquid and gas phase balancing pipelines are connected to the first and second pipelines in each refrigeration unit, respectively, to maintain consistent lubricating oil levels and pressures within multiple oil separation components. This allows lubricating oil to flow across units within the parallel compressor refrigeration system with gas-liquid balancing function, ensuring flexible lubricating oil supply based on the actual needs of each refrigeration unit, thereby guaranteeing the stability of oil supply throughout the entire parallel compressor refrigeration system with gas-liquid balancing function.

[0045] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0046] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the structure of a parallel compressor unit refrigeration system with gas-liquid balance function disclosed in the embodiments of this application. Figure 2 yes Figure 1A partial enlarged view at point A. In the figure, solid lines connecting components represent pipelines connecting the various components; solid arrows indicate the flow direction of lubricating oil, and dashed arrows indicate the flow direction of refrigerant. The parallel compressor unit refrigeration system 100 with gas-liquid balance function of this application includes multiple parallel refrigeration units 101, a liquid phase balance pipeline 102, and a gas phase balance pipeline 103. Each refrigeration unit 101 includes an evaporator 1, a condenser 2, multiple compressors 3, and an oil separation assembly 4. The condenser 2 is connected to the evaporator 1 via a pipeline to deliver liquid refrigerant to the evaporator 1. Multiple compressors 3 are arranged in parallel, and each compressor 3 is connected to the evaporator 1 via a pipeline to receive gaseous refrigerant delivered by the evaporator 1. The oil separator assembly 4 is provided with a first inlet 411, a first outlet 412, and a second outlet 413. The first inlet 411 is located near the top of the oil separator assembly 4 and is connected to multiple compressors 3 via pipes. The first inlet 411 is used to receive high-pressure gaseous refrigerant and liquid lubricating oil discharged from the compressors 3. The oil separator assembly 4 is configured to separate refrigerant and lubricating oil. The first outlet 412 is located at the bottom of the oil separator assembly 4 and is connected to the compressors 3 via a first pipe 31 to return the lubricating oil to the compressors 3. The second outlet 413 is located at the top of the oil separator assembly 4 and is connected to the condenser 2 via a second pipe 21 to deliver gaseous refrigerant to the condenser 2. A liquid phase balance pipe 102 is connected to the first pipe 31 in each refrigeration unit 101. The liquid phase balance pipe 102 is configured to allow lubricating oil to flow between the multiple oil separator assemblies 4 to maintain a consistent lubricating oil level in the multiple oil separator assemblies 4. The gas phase balance line 103 is connected to the second line 21 in each refrigeration unit 101. The gas phase balance line 103 is configured to allow gaseous refrigerant to flow between multiple oil separation components 4 so that the gas pressure in the multiple oil separation components 4 remains consistent.

[0047] The parallel compressor unit refrigeration system 100 with gas-liquid balance function disclosed in this application connects the first pipeline 31 of each refrigeration unit 101 (i.e., the oil return pipeline) through a liquid phase balance pipeline 102. This allows lubricating oil to flow through the liquid phase balance pipeline 102 to the refrigeration unit 101 with a lower oil level when the oil level in the oil separator 41 of one of the refrigeration units 101 is too high, ultimately achieving a uniform lubricating oil level in all oil separation components 4. Even if the different loads of the compressors 3 in the parallel compressor unit refrigeration system 100 result in differences in oil carrying capacity, the liquid phase balance pipeline 102 can quickly compensate for the lubricating oil level, preventing oil shortages or accumulation and ensuring a stable oil supply to the entire refrigeration unit 101.

[0048] Furthermore, by setting up a gas phase balance pipeline 103, which is connected to the second pipeline 21 (i.e., the return gas pipeline) of each refrigeration unit 101, pressure differences caused by pipeline resistance variations can be eliminated or avoided, preventing lubricating oil from migrating to a particular unit due to pressure and causing unwanted lubricating oil flow. Moreover, the liquid phase and gas phase balance pipelines 103 can work together to form a dual closed-loop regulation of pressure and liquid level, thereby ensuring uniform oil distribution. The two systems support each other, thus improving the stability of oil supply to the parallel compressor unit refrigeration system with gas-liquid balance function.

[0049] It is understood that the evaporator 1 mentioned above can be an air-cooled evaporator or a water-cooled evaporator, etc., and this embodiment does not make specific limitations on it.

[0050] It is understood that the condenser 2 mentioned above can be a finned tube condenser or a shell-and-tube condenser, etc., and this embodiment does not make specific limitations on it.

[0051] It is understood that the compressor 3 mentioned above can be a scroll compressor or a screw compressor, etc., and this embodiment does not make specific limitations on it.

[0052] It is understood that the refrigerant can be a Freon-like substance (such as R134a, R410A, R22, etc.) or ammonia, etc., and can be selected according to actual usage requirements. This embodiment does not make specific limitations on this.

[0053] It is understood that the lubricating oil can be mineral oil, synthetic oil, or alkylbenzene oil, etc., and the specific choice can be made according to the actual use requirements. This embodiment does not make any specific limitations on this.

[0054] It is understood that the above-mentioned liquid phase balance pipeline 102 and gas phase balance pipeline 103 are equipped with solenoid valves. When the parallel compressor unit refrigeration system 100 with gas-liquid balance function is operating normally, the solenoid valves are always kept open so that the lubricating oil level in the multiple oil separators 41 in the entire parallel compressor unit refrigeration system 100 with gas-liquid balance function is always kept the same.

[0055] In some embodiments, please refer to Figure 2 The oil separator assembly 4 is equipped with a level detection element 414 and an alarm 415. The level detection element 414 is configured to detect the level of lubricating oil in the oil separator assembly 4. The parallel compressor unit refrigeration system 100 with gas-liquid balance function also includes a control device (not shown in the figure). The control device is electrically connected to both the level detection element 414 and the alarm 415. The control device is configured to control the alarm 415 to sound an alarm when the level detection element 414 detects that the level of lubricating oil is at a first preset oil level.

[0056] By continuously monitoring the lubricating oil level in the oil separator 4 using a level detection element 414 installed within the oil separator 4, the control device immediately triggers an alarm 415 when the level reaches the first preset level. This mechanism can quickly detect oil level imbalances in the parallel compressor unit refrigeration system 100 with gas-liquid balance function, preventing problems such as oil shortage wear or oil slugging caused by the continuous expansion of abnormal oil levels.

[0057] It is understood that the liquid level detection component 414 mentioned above can be a float liquid level switch or a capacitive liquid level sensor, etc., and this embodiment does not specifically limit it.

[0058] It is understood that the aforementioned control device may be a programmable logic controller, a microcontroller, or a microprocessor, etc., and this embodiment does not specifically limit it.

[0059] It is understood that the alarm 415 mentioned above can be an audible and visual alarm, a buzzer, or a warning light, etc., and this embodiment does not make specific limitations on it.

[0060] It is understandable that the aforementioned first preset oil level is the lowest oil level in the oil separator assembly 4, that is, the lowest oil level that ensures the oil separator assembly 4 can normally supply oil to the first pipeline 31. When the oil level is lower than this first preset oil level, the oil separator assembly 4 cannot supply oil to the first pipeline 31 normally, which will affect the normal operation of the compressor 3. Under normal circumstances, the aforementioned gas phase balance pipeline 103 and liquid phase balance pipeline 102 can always ensure that the lubricating oil level in the oil separator assembly 4 in each refrigeration unit 101 is always above the first preset oil level. When the level detection element 414 detects that the lubricating oil level is at the first preset oil level, it indicates that the gas phase balance pipeline 103 or liquid phase balance pipeline 102 or other devices in the parallel compressor unit refrigeration system 100 with gas-liquid balance function may be malfunctioning. At this time, the control device controls the alarm 415 to sound an alarm, requiring personnel intervention for inspection and repair.

[0061] Understandably, since the liquid phase balance pipeline 102 is connected to the first pipeline 31 within each refrigeration unit 101 to allow lubricating oil to flow between multiple oil separation components 4, and the first pipeline 31 is also used by the oil separation components 4 to supply oil to the compressor 3, this necessitates switching between oil inlet and oil outlet states in the first pipeline 31. As an example, solenoid valves can be installed on both the first pipeline 31 and the liquid phase balance pipeline 102. The solenoid valve on the first pipeline 31 needs to be positioned closer to the compressor 3 at the connection point between the liquid phase balance pipeline 102 and the first pipeline 31, and the opening and closing of the two solenoid valves can be controlled by a control device. A detailed explanation will be provided using an example where the oil separation components 4 consist of two components: a first oil separation component and a second oil separation component. When the level sensor 414 detects that the lubricating oil in the first oil separator has reached the first preset level, it indicates that the first oil separator is in a state of oil shortage. At this time, the lubricating oil in the second oil separator needs to be replenished into the first oil separator. After receiving the signal from the level sensor, the control device controls the solenoid valves on the first pipelines of both oil separators to close, and simultaneously controls the solenoid valve on the liquid phase balance pipeline 102 to open. At this time, the lubricating oil in the second oil separator can be replenished into the first oil separator. When either the first or second oil separator needs to supply oil to the compressor 3, the control device controls the solenoid valve on the liquid phase balance pipeline 102 to close, and simultaneously controls the solenoid valve on the corresponding first pipeline 31 to open, so that the oil separator supplies oil to the compressor 3 in the refrigeration unit 101. Similarly, the second pipeline 21 also needs to switch between inlet and outlet states, and the implementation method is the same as described above, which will not be elaborated here.

[0062] Alternatively, please continue reading Figure 1 and Figure 2 The refrigeration unit 101 also includes a gas-liquid balance pipeline 104, which is connected to each oil separation component 4. A first solenoid valve 104a is installed on the gas-liquid balance pipeline 104. A control device is electrically connected to the first solenoid valve 104a. The control device is also configured to open the first solenoid valve 104a when the level detection element 414 detects that the lubricating oil level is at a second preset oil level, so as to keep the lubricating oil level and gas pressure in the multiple oil separation components 4 consistent. The first preset oil level is lower than the second preset oil level.

[0063] During normal operation, the oil separator 4 should always contain gaseous refrigerant and liquid lubricating oil, thus maintaining a constant gas-liquid contact surface. If this surface is too high, it indicates excessive lubricating oil in the oil separator 41, potentially leading to lubricating oil entering the condenser 2 and affecting its normal operation. Therefore, when the level sensor 414 detects that the lubricating oil level in the oil separator 4 has reached the second preset level, the control device opens the first solenoid valve 104a to maintain consistent lubricating oil levels and pressures across the multiple oil separators 4. This allows for rapid balancing of the refrigerant and lubricating oil within the oil separator 4 via the gas-liquid balance pipeline 104, ensuring the safe operation of the entire parallel compressor refrigeration system 100 with gas-liquid balance functionality.

[0064] In addition, the gas-liquid balance pipeline 104 can supplement the adjustment capacity of the liquid phase balance pipeline 102 and the gas phase balance pipeline 103 when they are insufficient, thereby further ensuring the oil level balance in the multiple oil separation components 4 in the entire parallel compressor unit refrigeration system 100 with gas-liquid balance function.

[0065] It is understandable that the height of the second preset oil level can be set at the middle of the oil separation component 4, or at a position slightly above the middle. The specific setting can be selected according to the actual situation, and this embodiment does not make a specific limitation on this.

[0066] It is understood that the first solenoid valve 104a mentioned above can be a ball valve type solenoid valve or a piston type solenoid valve, etc., and this embodiment does not make specific limitations on it.

[0067] Optionally, the bottom of the oil separation assembly 4 is provided with a heating element 416, which is configured to heat the lubricating oil in the oil separation assembly 4.

[0068] By setting a heating element 416 at the bottom of the oil separation component 4 to heat the lubricating oil, the increase in temperature can improve the fluidity of the lubricating oil. This allows the lubricating oil in the oil separation component 4 to always maintain a high fluidity state, so that when adjusting the oil level in the liquid phase balance pipeline 102 and the gas-liquid balance pipeline 104, it can flow more quickly between the oil separation components 4, thereby improving the efficiency of oil level balance.

[0069] It is understood that the heating element 416 may be an electric heating rod or an electromagnetic induction heating coil, etc., and this embodiment does not specifically limit it.

[0070] In some embodiments, please refer to Figures 1 to 3 , Figure 3 yes Figure 1A partial enlarged view at point B. The oil separation assembly 4 includes an oil separator 41 and a heat exchanger 42. The oil separator 41 has the aforementioned first inlet 411, first outlet 412, and second outlet 413. The heat exchanger 42 has a second inlet 421 and a third outlet 422 arranged opposite to each other along the height direction of the oil separator 41. The second inlet 421 is located at the top of the heat exchanger 42, and the third outlet 422 is located at the bottom of the heat exchanger 42. The second inlet 421 and the third outlet 422 are connected by a third pipe 422a. The first pipe 31 includes a first sub-pipe 311 and a second sub-pipe 312. The second inlet 421 and the first outlet 412 are connected through the first sub-pipe 311 to deliver lubricating oil into the heat exchanger 42 for heat exchange. The third outlet 422 is connected to the lubricating oil inlet of the compressor 3 through the second sub-pipe 312 to deliver the heat-exchanged lubricating oil into the corresponding compressor 3.

[0071] By setting up a heat exchanger 42, the third pipe 422a in the heat exchanger 42 is configured to exchange heat with the lubricating oil supplied by the oil separator 41, thereby adjusting the temperature of the lubricating oil separated by the oil separator 41 to a more suitable range to match the operating requirements of the compressor 3. Simultaneously, the segmented design of the first sub-pipe 311 and the second sub-pipe 312 allows the lubricating oil to be processed by the heat exchanger 42 before entering the compressor 3. If the temperature of the lubricating oil entering the compressor 3 is too high, on the one hand, the viscosity of the lubricating oil will decrease significantly with increasing temperature. When the viscosity of the lubricating oil is insufficient, it cannot form an effective oil film on the surface of the moving parts of the compressor 3 (such as the piston and cylinder wall, bearings, etc.), which will lead to increased friction between the parts and reduce the service life of the compressor 3. On the other hand, the lubricating oil also plays a cooling role in the compressor 3, carrying away not only the heat generated during operation through circulation. If the temperature of the lubricating oil entering the compressor 3 is too high, the amount of heat that the lubricating oil can absorb will decrease, thus affecting the cooling effect of the lubricating oil, causing the temperature of the compressor 3 to rise, and affecting the service life of the compressor 3. This can prevent the lubricating oil discharged from the first outlet 412 of the oil separator 41 from directly entering the compressor 3, which may cause temperature shock.

[0072] It is understood that the liquid level detection element 414, alarm 415 and heating element 416 are all installed inside the oil separator 41, and the gas-liquid balance pipeline 104 is connected to each oil separator 41 respectively.

[0073] It is understood that the heat exchanger 42 mentioned above can be a shell-and-tube heat exchanger 42 or a plate heat exchanger 42, etc., and this embodiment does not make specific limitations on it.

[0074] It is understood that the heat exchange medium used in the heat exchanger 42 can be additionally provided media such as water or heat transfer oil, or it can be liquid refrigeration extracted from the refrigeration unit 101. This will be explained in detail later.

[0075] Optionally, a filter device 311a is provided on the first sub-pipeline 311, which is configured to filter lubricating oil.

[0076] During the operation of the parallel compressor unit refrigeration system 100 with gas-liquid balance function, the lubricating oil may carry some solid impurities. If these solid impurities enter the compressor 3, they may scratch the surface of the compressor 3, thereby causing the compressor 3 to malfunction. By installing a filter device 311a on the first sub-pipe 311, solid impurities such as metal shavings, welding slag, and oxide scale in the lubricating oil can be effectively intercepted, thereby reducing the probability of malfunction of the parallel compressor unit refrigeration system 100 with gas-liquid balance function.

[0077] It is understood that the above-mentioned filtration device 311a may be a magnetic filter or a centrifugal filter, etc., and this embodiment does not specifically limit it.

[0078] Optionally, the compressor 3 includes a detection element (not shown in the figure) configured to detect the start and stop of the compressor 3. A second solenoid valve 312a is provided on the second sub-pipe 312, which controls the connection between the second sub-pipe and the third outlet 422. A control device is electrically connected to both the detection element and the solenoid valve, and is configured to control the solenoid valve to start or close according to the detection structure of the detection element.

[0079] By installing a detection element inside the compressor 3 to monitor the start-stop status of the compressor 3 in real time, the control device controls the opening and closing of the second solenoid valve 312a in conjunction with this status. Specifically, when the compressor 3 starts, the second solenoid valve 312a opens synchronously to ensure that lubricating oil is supplied to the compressor 3 in a timely manner. When the compressor 3 stops, the solenoid valve closes to prevent lubricating oil from continuing to flow into the compressor 3. This linkage mechanism avoids the continuous flow of lubricating oil into the compressor 3 after it has stopped, thereby preventing oil slugging caused by internal oil accumulation when the compressor 3 restarts, and also preventing oil shortage in the compressor 3 due to the solenoid valve not opening in time during operation.

[0080] It is understandable that the aforementioned detection device could be a current sensor, which determines the start-up and stop status of the compressor 3 by detecting changes in the current in the power supply circuit of the compressor 3. When the compressor 3 starts, the current increases, and when it stops, the current returns to zero. Alternatively, it could be a vibration sensor, which determines the start-up and stop status of the compressor 3 by detecting the mechanical vibration of the compressor 3 body. When the compressor 3 starts, the vibration amplitude increases, and when it stops, the vibration amplitude decreases.

[0081] It is understood that the second solenoid valve 312a is the same as the first solenoid valve 104a mentioned above, and this embodiment will not elaborate further on this.

[0082] In some embodiments, please refer to Figures 1 to 4 , Figure 4 This is a schematic diagram of the siphon liquid receiver disclosed in the embodiments of this application. The refrigeration unit 101 also includes a siphon liquid receiver 5, which has a first gas-liquid mixing inlet 521, a second gas-liquid mixing inlet 522, a first liquid outlet 531, a second liquid outlet 523, and a gas outlet 524. The first gas-liquid mixing inlet 521 and the gas outlet 524 are both connected to the condenser 2 via pipes to condense the gaseous refrigerant into a gas-liquid mixture. The first liquid outlet 531 is connected to the evaporator 1 via a pipe to deliver liquid refrigerant to the evaporator 1. The second gas-liquid mixing inlet 522 and the second liquid outlet 523 are both connected to the heat exchanger 42 to deliver liquid refrigerant into the evaporator 1 for heat exchange.

[0083] The siphon receiver 5 can be connected to the heat exchanger 42 through the second gas-liquid mixing inlet 522 and the second liquid outlet 523, and deliver low-temperature liquid refrigerant into the heat exchanger 42 to exchange heat with the lubricating oil, thereby reducing the temperature of the lubricating oil and providing a stable cold source for the lubricating oil heat exchange.

[0084] In addition, the siphon receiver 5 can simultaneously perform the functions of refrigerant gas-liquid separation, refrigerant storage, and liquid supply to the heat exchanger 42. In this way, the functions of both the gas-liquid separator and the receiver can be realized through a single siphon receiver 5, thereby simplifying the layout of the entire parallel compressor unit refrigeration system 100 with gas-liquid balance function.

[0085] Optionally, the siphon reservoir 5 is provided with a partition 51, which divides the interior of the siphon reservoir 5 into an interconnected siphon space 52 and a storage space 53. The first gas-liquid mixing inlet 521, the second gas-liquid mixing inlet 522, and the second liquid outlet 523 are all located in the siphon space 52, and the first liquid outlet 531 is located in the storage space 53, above the first liquid outlet 531.

[0086] By setting a partition 51, the siphon receiver 5 is divided into two interconnected spaces. The gas-liquid mixed refrigerant entering through the first gas-liquid mixing inlet 521 and the second gas-liquid mixing inlet 522 undergoes gas-liquid separation in the siphon space 52. The gaseous refrigerant can return to the condenser 2 more smoothly through the gas outlet 524, while the liquid refrigerant flows into the liquid storage space 53. This partitioned design reduces the probability of gaseous refrigerant entering the liquid storage space 53, resulting in a higher proportion of liquid refrigerant delivered to the evaporator 1 through the first liquid outlet 531, thereby improving the heat exchange efficiency of the evaporator 1.

[0087] In addition, the partition 51 can reduce the mutual interference between the siphon space 52 and the liquid storage space 53. For example, the partition 51 can reduce the impact of the gas-liquid impact of the first gas-liquid mixing inlet 521 on the liquid level stability of the liquid storage space 53, thereby enabling the liquid storage space 53 to supply liquid to the evaporator 1 more stably.

[0088] Optionally, the partition 51 is provided with a drain pipe 511, which is connected to the liquid storage space 53. The drain pipe 511 is provided with a drain port 511a, and the refrigerant in the siphon space 52 can enter the drain pipe 511 through the drain port 511a to enter the liquid storage space 53.

[0089] As a key channel connecting the siphon space 52 and the liquid storage space 53, the liquid drop pipe 511 can not only achieve effective transfer of liquid refrigerant, but also maintain the relative independence between the siphon space 52 and the liquid storage space 53 through the position of the liquid drop port 511a. The siphon space 52 can focus more on refrigerant exchange with the heat exchanger 42, and the liquid storage space 53 can more stably undertake the functions of buffering and liquid supply, reducing the mutual influence between the siphon space 52 and the liquid storage space 53, thereby improving the overall working efficiency of the siphon liquid receiver 5.

[0090] Please see Figure 4 It is understandable that the liquid discharge pipe 511 is a pipe with a certain height, the liquid discharge port 511a is located near the top of the liquid discharge pipe 511, and the second liquid outlet 523 is located near the bottom of the siphon space 52. This allows the liquid refrigerant separated in the siphon space 52 to be temporarily stored in the siphon space 52 first. The temporarily stored liquid refrigerant is first transported to the heat exchanger 42 through the second liquid outlet 523 to cool the lubricating oil. When the liquid refrigerant in the siphon space 52 reaches the liquid discharge port 511a, it can enter the liquid discharge pipe 511 and then enter the liquid storage space 53 for storage. This ensures that the liquid refrigerant is first used to cool the lubricating oil before being supplied to the evaporator 1.

[0091] Optionally, the refrigeration unit 101 also includes an expansion valve 6, which is connected to the first liquid outlet 531 and the evaporator 1 via pipelines. The expansion valve 6 is used to depressurize the refrigerant delivered by the siphon receiver 5 and then deliver it to the evaporator 1.

[0092] It is understood that the aforementioned expansion valve 6 can be a thermostatic expansion valve or an electronic expansion valve, etc., and this embodiment does not specifically limit it.

[0093] The following is a brief description of the refrigerant and lubricating oil circulation process in the parallel compressor unit refrigeration system 100 with gas-liquid balance function disclosed in this application:

[0094] Multiple compressors 3 within the refrigeration unit 101 supply liquid lubricating oil and gaseous refrigerant via pipelines to the first inlet 411 of the oil separator 41. In the oil separator 41, the liquid lubricating oil and gaseous refrigerant are separated. The separated liquid refrigerant is temporarily stored at the bottom of the oil separator 41. The lubricating oil is transported from the first outlet 412 to the heat exchanger 42 for cooling before being returned to the corresponding compressor 3. The separated gaseous refrigerant is transported from the second outlet 413 to the condenser 2, where it is condensed into a gas-liquid mixture. This mixture is then transported through the first gas-liquid mixing inlet 521 to the siphon receiver 5, where gas-liquid separation occurs in the siphon space 52. The separated liquid refrigerant is transported through the second liquid outlet 523 to the heat exchanger 42 for cooling the lubricating oil. The gas-liquid mixture returns to the siphon space 52 through the second gas-liquid mixing inlet 522. The separated gaseous refrigerant is then transported to the condenser 2. When the liquid refrigerant level in the siphon space 52 reaches the drain port 511a, it enters the drain pipe 511 through the drain port 511a and then enters the storage space 53 for storage. The storage space 53 delivers the liquid refrigerant to the expansion valve 6 through the first liquid outlet 531, where it is depressurized and then delivered to the evaporator 1. The evaporator 1 then delivers the gaseous refrigerant back to the corresponding compressor 3.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A parallel compressor unit refrigeration system with gas-liquid balance function, characterized in that, include: Multiple refrigeration units connected in parallel, the refrigeration units including: Evaporator; A condenser, which is connected to the evaporator via a pipe, to deliver liquid refrigerant to the evaporator; Multiple compressors are connected in parallel, and the compressors are connected to the evaporator through pipes to receive gaseous refrigerant delivered by the evaporator; An oil separation assembly is provided with a first inlet, a first outlet, and a second outlet. The first inlet is located near the top of the oil separation assembly and is connected to multiple compressors via pipelines. The first inlet is used to receive high-pressure gaseous refrigerant and liquid lubricating oil discharged from the compressors. The oil separation assembly is configured to separate the refrigerant and lubricating oil. The first outlet is located at the bottom of the oil separation assembly and is connected to the compressors via a first pipeline to return the lubricating oil to the compressors. The second outlet is located at the top of the oil separation assembly and is connected to the condenser via a second pipeline to deliver gaseous refrigerant to the condenser. A liquid phase balance pipeline is connected to the first pipeline in each of the refrigeration units. The liquid phase balance pipeline is configured to allow lubricating oil to flow between the multiple oil separation components so that the lubricating oil level in the multiple oil separation components remains consistent. A gas phase balancing pipeline is connected to the second pipeline in each of the refrigeration units. The gas phase balancing pipeline is configured to allow gaseous refrigerant to flow between the multiple oil separation components so that the gas pressure in the multiple oil separation components remains consistent.

2. The parallel compressor unit refrigeration system with gas-liquid balance function according to claim 1, characterized in that, The oil separation assembly is equipped with a liquid level detection device and an alarm. The liquid level detection device is configured to detect the liquid level height of the lubricating oil in the oil separation assembly. A control device is electrically connected to both the liquid level detection element and the alarm. The control device is configured to control the alarm to sound when the liquid level detection element detects that the level of the lubricating oil is at a first preset level.

3. The parallel compressor unit refrigeration system with gas-liquid balance function according to claim 2, characterized in that, The refrigeration unit also includes a gas-liquid balance pipeline, which is connected to each of the oil separation components. A first solenoid valve is provided on the gas-liquid balance pipeline. The control device is electrically connected to the first solenoid valve. The control device is also configured to control the first solenoid valve to open when the level detection element detects that the level of the lubricating oil is at a second preset level, so as to keep the lubricating oil level and gas pressure in the multiple oil separation components consistent. Wherein, the first preset oil level is lower than the second preset oil level.

4. The parallel compressor unit refrigeration system with gas-liquid balance function according to claim 1, characterized in that, The oil separator assembly is equipped with a heating element at its bottom, which is configured to heat the lubricating oil inside the oil separator assembly.

5. The parallel compressor unit refrigeration system with gas-liquid balance function according to claim 1, characterized in that, The oil separation assembly includes an oil separator and a heat exchanger, and the oil separator is provided with a first inlet, a first outlet and a second outlet; The heat exchanger is provided with a second inlet and a third outlet that are arranged opposite to each other along the height direction of the oil separator. The second inlet is located at the top of the heat exchanger, and the third outlet is located at the bottom of the heat exchanger. The second inlet and the third outlet are connected by a third pipeline. The first pipeline includes a first sub-pipeline and a second sub-pipeline. The second inlet is connected to the first outlet through the first sub-pipeline to send lubricating oil into the heat exchanger for heat exchange. The third outlet is connected to the lubricating oil inlet of the compressor through the second sub-pipeline to send the heat-exchanged lubricating oil into the corresponding compressor.

6. The parallel compressor unit refrigeration system with gas-liquid balance function according to claim 5, characterized in that, A filter device is provided on the first sub-pipeline, and the filter device is configured to filter the lubricating oil.

7. The parallel compressor unit refrigeration system with gas-liquid balance function according to claim 5, characterized in that, The compressor is equipped with a detection element configured to detect the start and stop of the compressor. A second solenoid valve is provided on the second sub-pipeline, which is used to control the connection between the second sub-pipeline and the third outlet. The parallel compressor unit refrigeration system with gas-liquid balance function also includes a control device, which is electrically connected to the detection element and the solenoid valve. The control device is configured to control the solenoid valve to start or close according to the detection result of the detection element.

8. The parallel compressor unit refrigeration system with gas-liquid balance function according to claim 5, characterized in that, The refrigeration unit also includes a siphon liquid receiver, which has a first gas-liquid mixing inlet, a second gas-liquid mixing inlet, a first liquid outlet, a second liquid outlet, and a gas outlet. The first gas-liquid mixing inlet and the gas outlet are both connected to the condenser through pipes to condense the gaseous refrigerant into a gas-liquid mixed refrigerant. The first liquid outlet is connected to the evaporator through a pipe to deliver the liquid refrigerant to the evaporator. The second gas-liquid mixing inlet and the second liquid outlet are both connected to the heat exchanger to deliver the liquid refrigerant into the evaporator for heat exchange.

9. The parallel compressor unit refrigeration system with gas-liquid balance function according to claim 8, characterized in that, The siphon reservoir is provided with a partition, which divides the interior of the siphon reservoir into an interconnected siphon space and a storage space. The first gas-liquid mixing inlet, the second gas-liquid mixing inlet, and the second liquid outlet are all located in the siphon space. The first liquid outlet is located in the storage space, and the second liquid outlet is located above the first liquid outlet.

10. The parallel compressor unit refrigeration system with gas-liquid balance function according to claim 9, characterized in that, The partition is provided with a liquid discharge pipe, which is connected to the liquid storage space. The liquid discharge pipe has a liquid discharge port, through which the refrigerant in the siphon space can enter the liquid discharge pipe and then enter the liquid storage space.

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