Oil circulation rate control test system for flammable and explosive working medium

Abstract

The invention discloses an oil circulation rate control test system for a flammable and explosive working medium, which is used for heating a refrigerant discharged from a compressor before entering an oil-gas separator, and a heat source is arranged outside an anti-explosion area or is separated from a heat exchange point by a specified distance. The oil circulation rate control test system can be used for flammable and explosive working media, especially for flammable and explosive refrigerants in a refrigerating system, the explosion risk can be avoided, the safety of the refrigerating system can be improved, and the separation efficiency of the oil separator can be effectively improved. The problem that the oil separator is poor in oil separation effect when the compressor is low in exhaust temperature and high in oil output is solved, and the oil liquid level and oil circulation rate control precision of compressor testing equipment or other related testing equipment is improved. The device is simple in structure, easy to implement, environmentally friendly and high in reliability, and the measurement precision of the oil liquid level and the oil circulation rate can be improved only with low cost. The heater can be placed outside the explosion-proof room and does not make direct contact with flammable and explosive refrigerants, and the use safety is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of air conditioners, and particularly to an oil circulation rate control test system for flammable and explosive working media. Background Art

[0002] In a refrigeration system, an oil separator is an important component. It can separate the oil discharged from the compressor and return it to the compressor to ensure the normal operation of the compressor. The solubility of oil and refrigerant decreases with the increase of temperature, which is more conducive to separating the oil mixed in the refrigerant in the oil separator. For compressor developers, accurately measuring the oil discharge rate or oil circulation rate of the compressor under specific working conditions is a very important part in the R & D process of the compressor, which directly affects the performance and energy consumption of the compressor.

[0003] Chinese Patent CN03102289.8 discloses an oil circulation flow rate measuring device for a refrigeration cycle. This device can accurately measure the oil circulation flow rate in the refrigeration cycle online and can perform high-precision flow control on the oil returned to the pipeline. Its composition includes an oil separator with an oil tank cylinder and a liquid level gauge in the refrigerant pipeline connected to the discharge side of the refrigeration compressor, a flow control valve or control pump and an oil flowmeter that can adjust the oil level height of the oil tank cylinder and are serially arranged on the oil outlet side pipeline of the oil tank cylinder, and a gas cooler connected to the refrigerant pipeline on the suction side of the refrigeration compressor, which mixes the oil flowing out from the oil outlet side pipeline with the refrigerant gas separated from the oil by the oil separator. There is a main technical problem to be solved in this solution. When the exhaust temperature of the compressor is low, the refrigerant carries oil into the oil separator and the oil tank cylinder. At this time, the temperature of the refrigerant and the oil is relatively low, and the solubility of oil and refrigerant increases with the decrease of temperature. At this time, the oil separation efficiency of the oil separator will decrease, far from reaching 99.9% described in the above patent.

[0004] Domestic and foreign counterparts have improved the above-mentioned existing patent problems, that is, electric heating wires or other heaters are attached to the outer wall surface of the oil separator and the outer wall surface of the oil tank cylinder. This can increase the temperature inside the oil separator, reduce the solubility of oil and refrigerant, make the refrigerant separate from the oil surface, and discharge from the oil separator to improve the oil separation efficiency of the oil separator. However, the technology of adding heating devices to the outer wall of the oil separator and the outer wall of the oil tank cylinder cannot completely solve the above technical problems, and cannot solve the explosion-proof electric heating for flammable and explosive or weakly flammable working media. There are still the following technical problems to be solved:

[0005] 1. The outer surface areas of the oil separator and the oil sump cylinder are subject to certain limitations, which also restrict the power of the externally wrapped electric heater. When the compressor displacement is large and the exhaust temperature is low, the refrigerant carries oil into the oil separator and the oil sump cylinder. Due to the limitation of the electric heating power, the heating effect of the oil separator and the oil sump cylinder is poor, the temperature of the oil and refrigerant mixture is low, and a large amount of refrigerant is dissolved in the oil in the oil sump cylinder and cannot separate from the oil surface and be discharged from the oil separator.

[0006] 2. For flammable, explosive or weakly flammable working fluids, since there is no customized externally wrapped heater with an explosion-proof certificate on the current market, the prior art cannot implement an oil heating device for a refrigeration system containing flammable, explosive or weakly flammable working fluids.

[0007] In recent years, with the increasing environmental protection requirements, environmentally friendly refrigerants have gradually been used in refrigeration systems to replace traditional Freons. The main currently used environmentally friendly refrigerants such as R290, R600a, etc. all belong to flammable and explosive working fluids. In addition, there are also some weakly flammable refrigerants such as R32, R1234yf, etc. on the current market. When applying and testing these flammable or weakly flammable refrigerants in compressors, heat exchangers, etc., the requirements for auxiliary electrical components are relatively high, and they must be explosion-proof devices inspected by relevant testing institutions. And the generally cost of certified explosion-proof devices is relatively high, especially customized devices. There is currently no customized heating wire or other wrapped heating device on the market that contains an explosion-proof certification. Without solving the above two technical problems, it cannot be applied to flammable, explosive or weakly flammable working fluids. On the other hand, the application of heat pumps is becoming more and more widespread now. During winter heat pumps or defrosting and defogging of cars, the suction and exhaust superheat of the compressor is often too low (<10°C), and the oil discharge volume is often very high (>10%) during the initial stage of compressor research and development. These two technical points cannot solve these problems. Summary of the Invention

[0008] A series of simplified concepts are introduced in the Summary of the Invention section. These simplified concepts are all simplified from the prior art in this field, which will be further described in detail in the Detailed Description section. The Summary of the Invention section of the present invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0009] The technical problem to be solved by the present invention is to provide an oil circulation rate control and test system that can be used for flammable, explosive or weakly flammable working fluids, can improve the oil separation efficiency, and particularly can still achieve high-efficiency oil separation in the oil separator and high-precision measurement and control of the oil circulation rate in the case of large oil discharge from the compressor and low exhaust superheat.

[0010] To solve the above technical problems, the oil circulation rate control test system for flammable and explosive working media provided by the present invention heats up the refrigerant discharged from the compressor 1 before it enters the oil-gas separator 3, and the heat source is arranged outside the explosion-proof area or at a specified distance from the heat exchange point, and the specified distance is determined according to the actual situation on site.

[0011] Preferably, further improve the oil circulation rate control test system for flammable and explosive working media, including:

[0012] Compressor 1, whose refrigerant outlet is connected to the heat exchanger 2, and whose refrigerant inlet is connected to;

[0013] Heat exchanger 2, which is used for heat exchange between the refrigerant and the heat exchange medium, and the refrigerant after heat exchange is sent to the oil separator 3;

[0014] Heat exchange medium heating device, which is arranged outside the explosion-proof area or at a specified distance from the heat exchanger 2, and is used for heating the heat exchange medium input into the heat exchanger 2 and the heating coil 4 of the oil separator;

[0015] Oil separator 3, whose refrigerant outlet is connected to the refrigerant inlet of the compressor 1, and whose oil outlet is connected to the oil inlet of the oil tank cylinder 5;

[0016] Oil tank cylinder 5, whose oil outlet is connected to the oil inlet of the compressor 1 through the oil circulation rate regulating valve 8 and the oil circulation flowmeter 9.

[0017] Preferably, further improve the oil circulation rate control test system for flammable and explosive working media, the heat exchange medium heating device includes:

[0018] Pump 10, whose inlet is connected to the heat exchange medium outlet of the heat exchanger 2 and the outlet of the heating coil 4 of the oil separator, and whose outlet is connected to the heat exchange medium inlet of the heat exchanger 2 and the inlet of the heating coil 4 of the oil separator through the heater 11 and the temperature sensor 12.

[0019] Preferably, further improve the oil circulation rate control test system for flammable and explosive working media, the oil outlet of the oil separator 3 is connected to the oil inlet of the oil tank cylinder 5 through a heating sleeve 13;

[0020] The heat exchange medium heating device is also used for heating the heat exchange medium input into the heating coil 14 of the oil tank cylinder.

[0021] Preferably, further improve the oil circulation rate control test system for flammable and explosive working media, the heat exchange medium heating device includes:

[0022] Pump 10, whose inlet is connected to the heat exchange medium outlet of the heat exchanger 2, the outlet of the heating coil 4 of the oil separator, the outlet of the heating sleeve 13 and the outlet of the heating coil 14 of the oil tank cylinder, and whose outlet is connected to the heat exchange medium inlet of the heat exchanger 2, the inlet of the heating coil 4 of the oil separator, the inlet of the heating sleeve 13 and the inlet of the heating coil 14 of the oil tank cylinder through the heater 11 and the temperature sensor 12.

[0023] Preferably, to further improve the oil circulation rate control test system for the flammable and explosive working medium, it further includes:

[0024] An oil level gauge 6, which is arranged in the oil tank cylinder 5;

[0025] An oil drain valve 7, which is formed at the bottom of the oil tank cylinder 5.

[0026] In the present invention, an exhaust heat exchanger is added between the compressor exhaust port and the oil separator. One side of the heat exchanger passes the flammable and explosive or other refrigerant, and the other side passes the high-temperature heating working medium. The high-temperature heating working medium can be heat-conducting oil or other high-boiling-point working media. After being cooled by the refrigerant, the working medium is heated by a heater located outside the explosion-proof room and then flows into the heat exchanger for heat exchange, thus forming a cycle. The power of the fluid between them is mainly realized by a pump. The present invention avoids the explosion-proof problem caused by the direct contact between the heater and the flammable working medium, and heats the low-temperature mixture of oil and refrigerant, so that the oil and refrigerant mixture has been heated to a relatively high temperature before entering the oil separator, which can improve the oil separation efficiency of the oil separator. By improving the oil separation efficiency of the oil separator, on the one hand, it can improve the measurement and control accuracy of the compressor test bench (the method specified in GB / T5773-2016), and on the other hand, it can still continue to use the methods in the existing patent ZL 03102289.8 for the oil circulation flow measurement device of the refrigeration cycle and the test device provided with this device to accurately control and measure the oil level and oil circulation rate.

[0027] The present invention can at least achieve the following technical effects;

[0028] 1. The present invention can be used for flammable and explosive working media, especially for the oil circulation rate control test system of flammable and explosive refrigerants in the refrigeration system, which can avoid the explosion risk, improve the safety of the refrigeration system, and effectively improve the separation efficiency of the oil separator. Correspondingly, the present invention is also applicable to non-flammable working media and weakly flammable working media. The present invention can still achieve high-efficiency oil separation of the oil separator and high-precision measurement and control of the oil circulation rate even in the case of large oil discharge from the compressor and low exhaust superheat.

[0029] 2. The heating coil of the present invention can be externally placed outside the oil separator and the oil tank cylinder, or can be internally placed in the oil tank cylinder, which increases the contact area between the coil and the oil separator and the oil tank cylinder, and can be in direct contact with the oil and refrigerant mixture in the oil tank cylinder, improving the heating effect.

[0030] 3. The present invention solves the problem of poor oil separation effect of the oil separator at low compressor exhaust temperature and high oil discharge volume, and improves the control accuracy of the oil level and oil circulation rate of the compressor test equipment or other related test equipment.

[0031] 4. The structure of the present invention is simple, easy to implement, environmentally friendly, and highly reliable. It can improve the measurement accuracy of the oil liquid level and the oil circulation rate with only low cost.

[0032] 5. The heater involved in the present invention can be placed outside the explosion-proof room. The heater does not directly contact with flammable and explosive refrigerants, greatly improving the safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings of the present invention are intended to illustrate the general characteristics of the methods, structures, and / or materials used in specific exemplary embodiments of the present invention, supplementing the description in the specification. However, the drawings of the present invention are schematic diagrams not drawn to scale, and thus may not accurately reflect the precise structure or performance characteristics of any given embodiment. The drawings of the present invention should not be construed as limiting or restricting the scope of the values or properties covered by the exemplary embodiments according to the present invention. The present invention will be further described in detail below in conjunction with the drawings and specific embodiments:

[0034] Figure 1 It is a schematic structural diagram of the first embodiment of the present invention.

[0035] Figure 2 It is a schematic structural diagram of the second embodiment of the present invention.

[0036] DESCRIPTION OF THE REFERENCE NUMERALS

[0037] Compressor 1

[0038] Heat exchanger 2

[0039] Oil separator 3

[0040] Oil separator heating coil 4

[0041] Oil tank cylinder 5

[0042] Oil level gauge 6

[0043] Oil drain valve 7

[0044] Oil circulation rate regulating valve 8

[0045] Oil circulation flowmeter 9

[0046] Pump 10

[0047] Heater 11

[0048] Temperature sensor 12. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] The following describes the implementation modes of the present invention through specific embodiments. Those skilled in the art can fully understand other advantages and technical effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific implementation modes. The details in this specification can also be applied based on different viewpoints, and various modifications or changes can be made without departing from the overall design concept of the invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. The following exemplary embodiments of the present invention can be implemented in many different forms and should not be construed as being limited only to the specific embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present invention complete and thorough, and to fully convey the technical solutions of these exemplary specific embodiments to those skilled in the art.

[0050] The first embodiment;

[0051] Referring to Figure 1 As shown, the present invention provides an oil circulation rate control test system for flammable and explosive working media, which heats the refrigerant discharged from the compressor 1 before it enters the oil-gas separator 3, and the heat source is arranged outside the explosion-proof area or at a specified distance from the heat exchange point.

[0052] The second embodiment;

[0053] Based on the design concept of the above first embodiment, the present invention provides an oil circulation rate control test system for flammable and explosive working media. The preferred embodiments include:

[0054] A compressor 1, whose refrigerant outlet is connected to a heat exchanger 2, and whose refrigerant inlet is connected to;

[0055] A heat exchanger 2, which is used for heat exchange between the refrigerant and the heat exchange medium. The refrigerant after heat exchange is sent to the oil separator 3;

[0056] A heat exchange medium heating device, which is arranged outside the explosion-proof area or at a specified distance from the heat exchanger 2, and is used for heating the heat exchange medium input into the heat exchanger 2 and the heating coil 4 of the oil separator. Specifically, it includes:

[0057] A pump 10, whose inlet is connected to the heat exchange medium outlet of the heat exchanger 2 and the outlet of the heating coil 4 of the oil separator, and whose outlet is connected to the heat exchange medium inlet of the heat exchanger 2 and the inlet of the heating coil 4 of the oil separator through a heater 11 and a temperature sensor 12;

[0058] An oil separator 3, whose refrigerant outlet is connected to the refrigerant inlet of the compressor 1, and whose oil outlet is connected to the oil inlet of the oil tank cylinder 5;

[0059] An oil tank cylinder 5, whose oil outlet is connected to the oil inlet of the compressor 1 through an oil circulation rate regulating valve 8 and an oil circulation flowmeter 9;

[0060] An oil level gauge 6, which is arranged in the oil sump cylinder 5;

[0061] An oil drain valve 7, which is formed at the bottom of the oil sump cylinder 5.

[0062] Among them, the heat exchanger 2 can be a plate type, a shell-and-tube type or any other device using indirect heat exchange. The indirect heating medium provides the circulating power through a pump, and the temperature of the medium is increased through a heater.

[0063] The heater 2 can be placed outside the explosion-proof room, and there is no special requirement for the heater itself to be explosion-proof or non-explosion-proof. After the heated medium is cooled by heat exchange, its temperature is increased after passing through the heater, and it is made to flow into the heat exchanger 2 through a pump to increase the temperature of the oil and refrigerant mixture discharged from the compressor, and at the same time improve the separation efficiency of the oil-gas separator. Here, it is necessary to ensure that the temperature of the heating medium is higher than the exhaust temperature of the compressor. The temperature of the oil heating medium can be measured by the temperature sensor 12, and its temperature value is controlled through the heater 11.

[0064] The heating device of the present invention increases the temperature of the low-superheat refrigerant and oil mixture and then enters the oil-gas separator for efficient separation. The separated oil is stored in the oil sump cylinder. There are mainly two control test methods for the oil circulation rate: 1. The oil sump cylinder is equipped with an oil level gauge 6, and the opening degree of the oil return regulating valve 8 is adjusted to reach the set liquid level value. 2. Set the oil circulation rate or oil flow rate, and according to the measured value of the oil flowmeter 9, adjust the opening degree of the oil return regulating valve 8 to reach the set oil circulation rate or oil flow rate.

[0065] The third embodiment;

[0066] Based on the design idea of the above first embodiment, the present invention provides an oil circulation rate control test system for flammable and explosive working media. The preferred embodiment includes:

[0067] A compressor 1, whose refrigerant outlet is connected to the heat exchanger 2, and whose refrigerant inlet is connected;

[0068] A heat exchanger 2, which is used for heat exchange between the refrigerant and the heat exchange medium, and the refrigerant after heat exchange is sent to the oil separator 3;

[0069] A heat exchange medium heating device, which is arranged outside the explosion-proof area or at a specified distance from the heat exchanger 2, and is used for heating the heat exchange medium input into the heat exchanger 2, the heating coil 4 of the oil separator and the heating coil 14 of the oil sump cylinder. Specifically, it includes:

[0070] A pump 10, whose inlet is connected to the heat exchange medium outlet of the heat exchanger 2, the outlet of the heating coil 4 of the oil separator, the outlet of the heating sleeve 13 and the outlet of the heating coil 14 of the oil sump cylinder, and whose outlet is connected to the heat exchange medium inlet of the heat exchanger 2, the inlet of the heating coil 4 of the oil separator, the inlet of the heating sleeve 13 and the inlet of the heating coil 14 of the oil sump cylinder through the heater 11 and the temperature sensor 12.

[0071] An oil separator 3, whose refrigerant outlet is connected to the refrigerant inlet of the compressor 1, and whose oil outlet is connected to the oil inlet of the oil tank cylinder 5 through a heating sleeve 13.

[0072] An oil tank cylinder 5, whose oil outlet is connected to the oil inlet of the compressor 1 through an oil circulation rate regulating valve 8 and an oil circulation flowmeter 9.

[0073] An oil level gauge 6, which is arranged in the oil tank cylinder 5.

[0074] An oil drain valve 7, which is formed at the bottom of the oil tank cylinder 5.

[0075] In this embodiment, the oil separator and the oil tank cylinder adopt a split form and are connected through a heating sleeve 13 in the middle. The inner tube in the heating sleeve is for the mixture of oil and refrigerant flowing from the oil separator to the oil tank cylinder, and the interlayer part between the inner and outer tubes is the oil heating medium for heating the mixture of oil and refrigerant in the inner tube. In addition, a heating coil 14 for the oil tank cylinder is added. The heating coil 14 can be placed outside or inside the oil tank cylinder, and the oil heating medium also passes through it for heating the mixture of oil and refrigerant in the oil tank cylinder.

[0076] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will also be understood that terms such as those defined in a general dictionary should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0077] The present invention has been described in detail above through specific embodiments and examples, but these do not constitute a limitation to the present invention. Without departing from the principle of the present invention, those skilled in the art can also make many modifications and improvements, which should also be regarded as the protection scope of the present invention.

Claims

1. An oil circulation rate control test system for flammable and explosive working fluids, characterized by: The refrigerant discharged from the compressor (1) is heated before entering the oil-gas separator (3), and the heat source is arranged outside the explosion-proof area or at a specified distance from the heat exchange point.

2. The oil circulation rate control test system for flammable and explosive working fluids according to claim 1, characterized in that: include: A compressor (1), whose refrigerant outlet is connected to a heat exchanger (2), whose refrigerant inlet is connected to; A heat exchanger (2) is used for exchanging heat between the refrigerant and the heat exchange medium, and the refrigerant after the heat exchange is sent to the oil separator (3); a heat exchange medium heating device, which is arranged outside the explosion-proof area or at a specified distance from the heat exchanger (2) and is used to heat the heat exchange medium input into the heat exchanger (2) and the oil separator heating coil (4); An oil separator (3), whose refrigerant outlet is connected to the refrigerant inlet of the compressor (1), and whose oil outlet is connected to the oil inlet of the oil tank cylinder (5); The oil tank cylinder (5) has an oil outlet connected to the oil inlet of the compressor (1) through an oil circulation rate regulating valve (8) and an oil circulation flow meter (9).

3. The oil circulation rate control test system for flammable and explosive working fluids according to claim 1, characterized in that: The heat exchange medium heating device comprises: The pump (10) has an inlet connected to the heat exchange medium outlet of the heat exchanger (2) and the outlet of the oil separator heating coil (4), and an outlet connected to the heat exchange medium inlet of the heat exchanger (2) and the inlet of the oil separator heating coil (4) via a heater (11) and a temperature sensor (12).

4. The oil circulation rate control test system for flammable and explosive working fluids according to claim 1, characterized in that: The oil outlet of the oil separator (3) is connected to the oil inlet of the oil tank cylinder (5) via a heating sleeve (13); The heat exchange medium heating device is also used to heat the heat exchange medium input into the oil tank heating coil (14).

5. The oil circulation rate control test system for flammable and explosive working fluids according to claim 4, characterized in that: The heat exchange medium heating device comprises: The pump (10) has an inlet connected to the heat exchange medium outlet of the heat exchanger (2), the outlet of the oil separator heating coil (4), the outlet of the heating sleeve (13) and the outlet of the oil tank heating coil (14), and its outlet is connected to the heat exchange medium inlet of the heat exchanger (2), the inlet of the oil separator heating coil (4), the inlet of the heating sleeve (13) and the inlet of the oil tank heating coil (14) via the heater (11) and the temperature sensor (12).

6. The oil circulation rate control test system for flammable and explosive working fluids according to any one of claims 1 to 5, characterized in that: Also includes: An oil level gauge (6) is arranged in the oil tank (5); The oil drain valve (7) is formed at the bottom of the oil tank cylinder (5).

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