Lubricant recovery system for heat exchange system and heat exchange system

Abstract

The present invention relates to a lubricant recovery system for a heat exchange system and a heat exchange system. The heat exchange system includes a compressor, a condenser, an expansion device, and an evaporator connected in sequence to form a loop, and further includes a reservoir for storing lubricant that communicates with the compressor. The lubricant recovery system includes: a first flow path provided between the suction chamber of the compressor and the reservoir, and having a first pump and a first filter, the first pump being configured to pump a part of the lubricant in the suction chamber to the reservoir, and the first filter being provided upstream of the first pump for filtering the lubricant; and / or a second flow path provided between the evaporator and the suction chamber, and having a second pump and a second filter, the second pump being configured to pump a mixture of lubricant and refrigerant from the evaporator to the suction chamber, and the second filter being provided upstream of the second pump for filtering the mixture.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange, and particularly to a lubricant recovery system for a heat exchange system and a heat exchange system including the lubricant recovery system. Background Art

[0002] The prior art provides many types of heat exchange systems such as HVAC (Heating, Ventilation and Air Conditioning), which have been widely used in many industrial fields, places, etc., and can bring great convenience to people's daily production and life, etc. A large number of various types of components, devices, units or equipment, etc. are provided in these existing heat exchange systems to achieve functions such as refrigeration, heating, air exchange, etc. However, they still have some drawbacks and deficiencies in aspects such as structural configuration, heat exchange effect, system performance, manufacturing and maintenance costs, etc., and can be further improved and optimized. For example, for the compressor in a heat exchange system, ensuring the effective recovery of the compressor lubricating oil is one of the key factors for the stable operation of the compressor. In the current oil recovery system, an ejector (or called a jet pump) is generally used, which requires a sufficient pressure difference between the compressor and the evaporator to work properly. However, it is difficult to provide a reliable pressure difference in application environments such as low lift, which will affect the working efficiency and operation safety of the entire system. Summary of the Invention

[0003] In view of this, the present invention provides a lubricant recovery system for a heat exchange system and a heat exchange system including the lubricant recovery system, thereby solving or at least alleviating one or more of the above problems and other problems existing in the prior art.

[0004] First, according to a first aspect of the present invention, it provides a lubricant recovery system for a heat exchange system, the heat exchange system includes a compressor, a condenser, an expansion device and an evaporator connected in series to form a loop, and further includes a reservoir for storing lubricant communicated with the compressor, the lubricant recovery system includes:

[0005] A first flow path, which is arranged between the suction chamber of the compressor and the reservoir, and has a first pump and a first filter, the first pump is used to pump a part of the lubricant in the suction chamber to the reservoir, and the first filter is arranged upstream of the first pump for filtering the lubricant; and / or

[0006] A second flow path is provided between the evaporator and the suction chamber, and has a second pump and a second filter. The second pump is configured to pump a mixture of lubricant and refrigerant from the evaporator to the suction chamber, and the second filter is disposed upstream of the second pump for filtering the mixture.

[0007] In the lubricant recovery system according to the present invention, optionally, the lubricant recovery system further includes a first liquid level control device and a first controller. The first liquid level control device is configured to monitor the liquid level in the suction chamber, and the first controller is configured to control the operation of the first pump according to the monitored liquid level.

[0008] In the lubricant recovery system according to the present invention, optionally, the first liquid level control device includes at least one upper liquid level sensor and at least one lower liquid level sensor, which are respectively configured to monitor the upper liquid level and the lower liquid level in the suction chamber.

[0009] In the lubricant recovery system according to the present invention, optionally, the lubricant recovery system further includes a second liquid level control device and a second controller. The second liquid level control device is configured to monitor the liquid level in the evaporator, and the second controller is configured to control the operation of the second pump according to the monitored liquid level.

[0010] In the lubricant recovery system according to the present invention, optionally, the first controller and the second controller are the same controller or independent controllers from each other.

[0011] In the lubricant recovery system according to the present invention, optionally, the first flow path further has at least one first valve for controlling the flow of the lubricant in the first flow path, and / or the second flow path further has at least one second valve for controlling the flow of the mixture in the second flow path.

[0012] In the lubricant recovery system according to the present invention, optionally, the first flow path has two of the first valves, which are respectively disposed upstream of the first filter and downstream of the first pump, and / or the second flow path has two of the second valves, which are respectively disposed upstream of the second filter and downstream of the second pump.

[0013] In the lubricant recovery system according to the present invention, optionally, the first pump is a gas-liquid two-phase pump, which is at least partially immersed in the lubricant pumped therethrough, and / or the second pump is a gas-liquid two-phase pump, which is at least partially immersed in the fluid pumped therethrough.

[0014] In the lubricant recovery system according to the present invention, optionally, the first pump and / or the second pump is an electromagnetic pump, and the compressor is a centrifugal compressor, a rotary compressor, a turbo compressor, a reciprocating compressor or a screw compressor.

[0015] Secondly, according to a second aspect of the present invention, it further provides a heat exchange system, which includes a compressor, a condenser, an expansion device and an evaporator connected in series to form a loop, and further includes a reservoir for storing lubricant communicated with the compressor. The heat exchange system further includes the lubricant recovery system as described in any one of the above.

[0016] From the following detailed description in combination with the drawings, the principles, characteristics, features and advantages of the technical solutions according to the present invention will be clearly understood. For example, compared with the prior art, the technical solutions of the present invention are not only easy to manufacture, install and maintain, have low use costs and a wide application range, but also can replace devices such as ejectors commonly used in the industry at present, can effectively ensure the lubricant recovery effect in the heat exchange system, improve the working efficiency, safety and reliability of the system. Therefore, the present invention has remarkable practicality. Description of the Drawings

[0017] The technical solutions of the present invention will be further described in detail below in combination with the drawings and embodiments. However, it should be understood that these drawings are only designed for explanatory purposes, and are only intended to conceptually illustrate the structural configurations described herein, and are not necessarily drawn to scale.

[0018] Figure 1 is a schematic composition diagram of an embodiment of a heat exchange system according to the present invention, in which an example of a lubricant recovery system is shown.

[0019] Figure 2 is Figure 1 a schematic layout diagram of the first flow path in the example of the lubricant recovery system shown in, the compressor and the reservoir in the embodiment of the heat exchange system.

[0020] Figure 3 is Figure 1 a schematic layout diagram of the second flow path in the example of the lubricant recovery system shown in, the compressor and the evaporator in the embodiment of the heat exchange system. Detailed Description of the Embodiments

[0021] First of all, it should be noted that the composition, working principle, characteristics and advantages of the lubricant recovery system for a heat exchange system according to the present invention and the heat exchange system including the lubricant recovery system will be described below by way of example. However, it should be understood that all the descriptions are only given for the purpose of illustration, and should not be construed as any limitation to the present invention.

[0022] In this text, the technical terms "first" and "second" are only for the purpose of making a discriminatory description, and are not intended to indicate their order and relative importance. In addition, for any single technical feature described or implied in the embodiments mentioned in this text, or any single technical feature shown or implied in the respective drawings, the present invention still allows any combination or deletion to continue between these technical features (or their equivalents) without any technical obstacles, thereby obtaining more other embodiments of the present invention that may not be directly mentioned in this text.

[0023] In Figure 1 a general composition of an embodiment of a heat exchange system according to the present invention is schematically shown, and in Figure 2 and Figure 3 the arrangement of the first flow path and the second flow path in an example of the lubricant recovery system therein is further shown. The technical solution of the present invention will be described in detail below in conjunction with these drawings.

[0024] As Figure 1 shown, in this embodiment of the heat exchange system, a compressor 1, a condenser 2, an expansion device 3, and an evaporator 4 are sequentially connected in a loop, and a reservoir 5 for storing lubricants (such as various lubricating oils, etc.) is also provided. They can be connected and arranged as shown in the figure, so that the heat exchange system can realize functions such as refrigeration, heating, and / or air exchange by means of the circulation of the refrigerant in the system, and can play roles such as lubricating and cooling the compressor in the system by recycling the lubricant.

[0025] It should be understood that the above-mentioned heat exchange system is only for illustrative purposes. In actual application scenarios, any possible components, units, devices, or equipment (such as heat exchangers, valves, condensers, economizers, oil-gas separators, expansion devices, etc.) can be added, reduced, or replaced, and flexible selection and setting of their specific models, arrangement positions, quantities, etc. are allowed. For example, the compressor 1 can be a centrifugal compressor, a rotary compressor, a turbo compressor, a reciprocating compressor, or a screw compressor. Another example is that the lubricant stored in the reservoir 5 can be pumped to the compressor 1 after heat exchange treatment through devices such as pumps and heat exchangers not shown in Figure 1 the figure.

[0026] In Figure 1 the embodiment of the heat exchange system, an example of a lubricant recovery system according to the present invention is provided. It can include two flow paths for realizing lubricant recovery, namely the first flow path 6 and the second flow path 7. Among them, the first flow path 6 is arranged between the suction chamber of the compressor 1 and the reservoir 5 ( Figure 2 ), and the second flow path 7 is arranged between the evaporator 4 and the suction chamber ( Figure 3 ).

[0027] Please refer to Figure 2 , the first flow path 6 is used to recycle the lubricant at the compressor 1 back to the reservoir 5 so that the heat exchange system can recycle the lubricant stored in the reservoir 5, thereby bringing positive effects such as lubrication, temperature reduction, and extended service life to, for example, the compressor 1 in the heat exchange system. As Figure 2 shown, a pump 61, a filter 62, a valve 63, and a valve 64 can be provided in the first flow path 6.

[0028] Specifically, the pump 61 is arranged to pump a part of the lubricant in the suction chamber of the compressor 1 to the reservoir 5, and in practical applications, it can adopt any suitable pump device such as an electromagnetic pump. By arranging the pump 61 in the first flow path 6, even in the face of application environments such as low lift, rapid, stable, and reliable recovery operation of the lubricant from the suction chamber of the compressor 1 to the reservoir 5 can be achieved, which is not available in existing lubricant recovery systems (for example, ejectors are commonly used therein).

[0029] It should be noted that if there are foreign matters in the lubricant fluid flowing through the pump 61, this may cause the pump 61 to malfunction or be damaged. Therefore, in order to avoid the above problems, the filter 62 can be arranged upstream of the pump 61 to filter out the above foreign matters, thereby ensuring and improving the safety and reliability of the system.

[0030] As Figure 2 shown, the valve 63 and the valve 64 can adopt any suitable valve device such as a solenoid valve, and they are respectively arranged upstream of the filter 62 and downstream of the pump 61, thereby enabling flexible control of the flow of the lubricant in the first flow path 6, which can facilitate operations such as system operation and maintenance, equipment repair, commissioning, and replacement. Of course, according to different application requirements, three or more valves can be considered to be provided in the first flow path 6, or only one valve may be provided. It should be understood that in the first flow path 6, the specific models, arrangement positions, and numbers of the valves discussed above are all allowed to be flexibly selected and set.

[0031] Generally speaking, lubricant mostly exists in liquid form in the suction chamber of the compressor 1. It is not desirable to have too much or too little lubricant in this suction chamber. This is because, once there is too much lubricant in the suction chamber of the compressor 1, it will affect the effective suction volume of the compressor 1 and is not conducive to its stable and efficient operation; however, if there is too little lubricant in the suction chamber of the compressor 1, it may cause the pump 61 to not operate stably and reliably for a long time. For example, in adverse situations, the pump 61 may need to be frequently stopped to avoid the pump running idle due to no lubricant or very little lubricant in the suction chamber. Therefore, a first liquid level control device and a first controller can be configured for this lubricant recovery system, so that the former is used to monitor the liquid level in the suction chamber of the compressor 1, and the latter is used to control the operation of the pump 61 according to the monitored liquid level, so that the lubricant can always maintain an appropriate amount in the suction chamber of the compressor 1, avoiding the undesirable phenomena of too much or too little liquid inventory in the suction chamber, which will be very helpful to ensure that the compressor 1, the pump 61, etc. can operate for a long time, reliably and efficiently.

[0032] In an alternative scenario, one or more upper liquid level sensors 8 can be arranged in the suction chamber of the compressor 1 as shown in Figure 2 , and one or more lower liquid level sensors 9 can be arranged simultaneously, so as to respectively monitor the upper liquid level and the lower liquid level of the liquid in the suction chamber of the compressor 1 through them, thereby knowing the current liquid inventory situation in this suction chamber.

[0033] In addition, in an alternative scenario, the above-mentioned first controller can be implemented by any suitable hardware, software or their combination. The first controller can be provided separately, or integrated into the control components of the pump 61 itself, or integrated into any suitable components, units, modules, devices or equipment in the heat exchange system.

[0034] Please refer to Figure 3 again. The second flow path 7 is used to transport the mixture of lubricant and refrigerant at the evaporator 4 (usually may exist in the form of a gas-liquid two-phase) to the suction chamber of the compressor 1 together. The lubricant entering this suction chamber can be recycled after being recovered through the above-mentioned first flow path 6, or it can still be recycled after being recovered by using the existing recovery system (such as including an ejector, etc.).

[0035] As shown in Figure 3As shown, a pump 71, a filter 72, valves 73 and 74 can be provided in the second flow path 7, and a second liquid level control device and a second controller can also be provided. The second liquid level control device can use, for example, a liquid level sensor 10 to monitor the liquid level in the evaporator 4, and the second controller can be used to control the operation of the pump 71 according to the monitored liquid level, so as to avoid adverse phenomena such as the pump 71 idling due to the absence of mixture liquid or its very small stock in the evaporator 4.

[0036] Here, it should be noted that unless specifically pointed out in this article, the relevant descriptions of the pump 61, the filter 62, the valves 63 and 64, the first liquid level control device and the first controller of the heat exchanger in the first flow path 6 in the foregoing can be respectively applied to the pump 71, the filter 72, the valves 73 and 74, the second liquid level control device and the second controller in the second flow path 7 in the same or similar manner, so they will not be repeated here. In addition, it should also be noted that the above-mentioned first controller and second controller can be implemented independently of each other, or they can be integrated into the same controller, and such a controller can be implemented by hardware, software or a combination of them.

[0037] Without departing from the gist of the present invention, the present invention allows various possible flexible designs, changes and adjustments according to actual application situations.

[0038] For example, in some embodiments, only the first flow path 6 or the second flow path 7 can be provided to replace a part of the recovery flow path of the existing lubricant recovery system (such as an ejector is provided therein). Again, in some embodiments, the above-mentioned valves 63, 64, 73 and 74 may not be provided, and the first liquid level control device and the second controller, or the second liquid level control device and the second controller can also be removed to meet the actual requirements in some application scenarios, such as simplifying the system and reducing costs.

[0039] In addition, for the above-mentioned pump 61 and pump 71, any type of pump device can be used when they are in use. For example, a pump device suitable for a gas-liquid two-phase environment can be used so that it can be partially or completely immersed in the fluid to be pumped (such as lubricant or mixture). This arrangement is very beneficial to cool the pump itself during its operation, enabling it to work more reliably for a longer time, thereby effectively ensuring the efficient and stable operation of the entire system. Of course, according to the actual requirements in different application scenarios, the pump 61 and / or the pump 71 may not use the above-mentioned gas-liquid two-phase pump but use other types of pump devices (such as a pump device that does not need to be immersed in liquid), which are allowed in the technical solution of the present invention.

[0040] The above has only elaborated in detail, by way of example, the lubricant recovery system for a heat exchange system according to the present invention and the heat exchange system including the lubricant recovery system. These examples are only for explaining the principle and its implementation manners of the present invention, rather than limiting the present invention. Without departing from the spirit and scope of the present invention, those skilled in the art can also make various deformations and improvements. Therefore, all equivalent technical solutions should fall within the scope of the present invention and be defined by the various claims of the present invention.

Claims

1. A lubricant recovery system for a heat exchange system, the heat exchange system including a compressor, a condenser, an expansion device, and an evaporator connected in sequence to form a loop, and further including a reservoir for storing lubricant communicated with the compressor, characterized in that, The lubricant recovery system includes: A first flow path, which is arranged between the suction chamber of the compressor and the reservoir, and has a first pump and a first filter. The first pump is used to pump a part of the lubricant in the suction chamber to the reservoir. The first filter is arranged upstream of the first pump for filtering the lubricant. Wherein the first pump includes an electromagnetic pump or a gas-liquid two-phase pump; and A second flow path, which is arranged between the evaporator and the suction chamber, and has a second pump and a second filter. The second pump is used to pump the mixture of lubricant and refrigerant from the evaporator to the suction chamber. The second filter is arranged upstream of the second pump for filtering the mixture. Wherein the second pump includes an electromagnetic pump or a gas-liquid two-phase pump.

2. The lubricant recovery system according to claim 1, wherein, The lubricant recovery system further includes a first liquid level control device and a first controller. The first liquid level control device is used to monitor the liquid level in the suction chamber. The first controller is configured to control the operation of the first pump according to the monitored liquid level.

3. The lubricant recovery system according to claim 2, wherein, The first liquid level control device includes at least one upper liquid level sensor and at least one lower liquid level sensor, which are respectively used to monitor the upper liquid level and the lower liquid level in the suction chamber.

4. The lubricant recovery system according to claim 2, wherein, The lubricant recovery system further includes a second liquid level control device and a second controller. The second liquid level control device is used to monitor the liquid level in the evaporator. The second controller is configured to control the operation of the second pump according to the monitored liquid level.

5. The lubricant recovery system according to claim 4, wherein, The first controller and the second controller are the same controller or independent controllers from each other.

6. The lubricant recovery system according to claim 1, wherein, The first flow path further has at least one first valve for controlling the flow of the lubricant in the first flow path, and / or the second flow path further has at least one second valve for controlling the flow of the mixture in the second flow path.

7. The lubricant recovery system according to claim 6, wherein, The first flow path has two of the first valves, which are respectively arranged upstream of the first filter and downstream of the first pump, and / or the second flow path has two of the second valves, which are respectively arranged upstream of the second filter and downstream of the second pump.

8. The lubricant recovery system according to any one of claims 1-7, wherein, The first pump uses a gas-liquid two-phase pump, which is at least partially immersed in the lubricant pumped by it, and / or the second pump uses a gas-liquid two-phase pump, which is at least partially immersed in the fluid pumped by it.

9. The lubricant recovery system according to claim 8, wherein The first pump and / or the second pump is an electromagnetic pump. The compressor is a centrifugal compressor, a rotary compressor, a turbo compressor, a reciprocating compressor or a screw compressor.

10. A heat exchange system, which includes a compressor, a condenser, an expansion device and an evaporator connected in sequence to form a loop, and further includes a reservoir for storing lubricant communicated with the compressor, characterized in that, The heat exchange system further includes the lubricant recovery system according to any one of claims 1-9.

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