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

Abstract

The utility model discloses an oil circulation rate control test system for a flammable and explosive working medium, which is used for heating a refrigerant discharged by a compressor before the refrigerant enters 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, and is characterized in that a refrigerant outlet of the compressor is connected with a heat exchanger, and a refrigerant inlet of the compressor is connected with the heat exchanger; the heat exchanger is used for exchanging heat between a refrigerant and a heat exchange medium, and the refrigerant subjected to heat exchange is fed into the oil-gas separator; the heat exchange medium heating device is arranged outside the anti-explosion area or is separated from the heat exchanger by a specified distance, and is used for heating a heat exchange medium input into the heat exchanger and a heating coil of the oil-gas separator; a refrigerant outlet of the oil-gas separator is connected with a refrigerant inlet of the compressor, and an oil outlet is connected with an oil inlet of the oil groove cylinder; an oil outlet of the oil groove cylinder is connected with an oil inlet of the compressor through an oil circulation rate adjusting valve and an oil circulation flowmeter. The device is simple in structure, easy to implement, environment-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.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning, and in particular to an oil circulation rate control and testing system for flammable and explosive working fluids. Background Technology

[0002] In refrigeration systems, the oil separator is a crucial component. It separates the oil discharged from the compressor and returns it to the compressor, ensuring its normal operation. The miscibility of oil and refrigerant decreases with increasing temperature, making it easier to separate oil mixed in the refrigerant in the oil separator. For compressor developers, accurately measuring the compressor's oil discharge rate or oil circulation rate under specific operating conditions is a vital part of the compressor development process, directly impacting compressor performance and energy consumption.

[0003] Chinese patent CN03102289.8 discloses an oil circulation flow measurement device for a refrigeration cycle. This device can measure the oil circulation flow in the refrigeration cycle with high precision online and can also perform high-precision flow control on the oil returning to the pipeline. Its components include an oil-gas separator with an oil tank and a level gauge connected to the refrigerant pipeline on the discharge side of the refrigeration compressor; a flow control valve or control pump and an oil flow meter connected in series on the oil outlet side pipeline of the oil tank to adjust the oil level in the oil tank; and a gas cooler connected to the refrigerant pipeline on the suction side of the refrigeration compressor to mix the oil flowing from the oil outlet side pipeline with the refrigerant gas separated by the oil-gas separator. A major technical problem with this solution is that when the compressor discharge temperature is low, the refrigerant carries oil into the oil-gas separator and oil tank. At this time, the temperature of the refrigerant and oil is low, and the solubility of oil and refrigerant increases as the temperature decreases. Consequently, the oil separation efficiency of the separator decreases, far below the 99.9% described in the patent.

[0004] Domestic and international counterparts have made improvements to the aforementioned patented issues by attaching electric heating wires or other heaters to the outer walls of the oil-gas separator and the oil tank. This increases the temperature inside the oil separator, reduces the miscibility of oil and refrigerant, causes the refrigerant to detach from the oil surface, and exits the oil-gas separator, thereby improving the oil separation efficiency. However, adding heating devices to the outer walls of the oil-gas separator and the oil tank cannot completely solve the above-mentioned technical problems, and it cannot address the issue of using explosion-proof electric heating with flammable, explosive, or weakly flammable working fluids. The following technical problems still need to be solved:

[0005] 1. The limited outer surface area of ​​the oil-gas separator and oil tank restricts the power of the external electric heating element. When the compressor displacement is large and the exhaust temperature is low, the refrigerant carries oil into the oil-gas separator and oil tank. Due to the limited electric heating power, the heating effect of the oil-gas separator and oil tank is poor. The temperature of the oil-refrigerant mixture is low, and a large amount of refrigerant dissolves in the oil in the oil tank, unable to detach from the oil surface and be discharged from the oil-gas separator.

[0006] 2. For flammable, explosive, or weakly flammable working fluids, since there are currently no customized outsourced heaters with explosion-proof certifications on the market, existing technologies cannot realize oil heating devices containing flammable, explosive, or weakly flammable working fluid refrigeration systems.

[0007] In recent years, with increasingly stringent environmental protection requirements, environmentally friendly refrigerants have gradually replaced traditional Freon in refrigeration systems. Currently, the main environmentally friendly refrigerants used, such as R290 and R600a, are flammable and explosive. Additionally, some weakly flammable refrigerants such as R32 and R1234yf are also available on the market. When these flammable or weakly flammable refrigerants are used in compressors, heat exchangers, etc., the requirements for auxiliary electrical components are relatively high. These components must be explosion-proof devices certified by relevant testing institutions. However, certified explosion-proof devices are generally expensive, especially custom-made ones. Currently, there are no custom-made heating wires or other encased heating devices on the market with explosion-proof certification. As mentioned above, without solving these two technical problems, they cannot be used with flammable, explosive, or weakly flammable refrigerants. On the other hand, with the increasing use of heat pumps, the superheat of the compressor's suction and discharge is often low (<10℃) during winter defrosting or defogging in automobiles, and the oil discharge rate is often very high (>10%) in the early stages of compressor development. Neither of the above two technical points can solve these problems. Utility Model Content

[0008] The utility model description section introduces a series of simplified concepts, all of which are simplifications of existing technologies in the field, and will be further explained in detail in the detailed description section. This utility model description section is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0009] The technical problem to be solved by this utility model is to provide an oil circulation rate control and testing system that can be used with flammable, explosive or weakly combustible working fluids, improve oil-liquid separation efficiency, and especially achieve high-efficiency oil separation and high-precision measurement and control of oil circulation rate in oil-gas separators under conditions such as large compressor oil discharge and low exhaust superheat.

[0010] To solve the above-mentioned technical problems, the present invention provides an oil circulation rate control and testing system for flammable and explosive working fluids, 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 exchanger, the specified distance being determined according to the actual site conditions.

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

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

[0013] Heat exchanger 2 is used for heat exchange between refrigerant and heat exchange medium. The refrigerant after heat exchange is sent to oil-gas separator 3.

[0014] A heat exchange medium heating device 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 to the heat exchanger 2 and the heating coil 4 of the oil-gas separator.

[0015] The oil-gas separator 3 has its refrigerant outlet connected to the refrigerant inlet of the compressor 1 and its oil outlet connected to the oil inlet of the oil tank 5.

[0016] The oil tank 5 has its oil outlet connected to the oil inlet of the compressor 1 via the oil circulation rate regulating valve 8 and the oil circulation flow meter 9.

[0017] Preferably, in a further improved oil circulation rate control and testing system for the flammable and explosive working fluid, the heat exchange medium heating device includes:

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

[0019] Preferably, the oil circulation rate control test system for the flammable and explosive working fluid is further improved, wherein the oil outlet of the oil-gas separator 3 is connected to the oil inlet of the oil tank cylinder 5 via a heating sleeve 13.

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

[0021] Preferably, in a further improved oil circulation rate control and testing system for the flammable and explosive working fluid, the heat exchange medium heating device includes:

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

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

[0024] Oil level gauge 6 is arranged in oil tank 5;

[0025] The oil drain valve 7 is formed at the bottom of the oil tank 5.

[0026] This invention adds an exhaust heat exchanger between the compressor discharge port and the oil-gas separator. One side of the heat exchanger carries flammable, explosive, or other refrigerants, while the other side carries a high-temperature heating medium, which can be heat transfer oil or other high-boiling-point medium. The medium is cooled by the refrigerant and then heated by a heater located outside the explosion-proof compartment before flowing back into the heat exchanger for heat exchange, thus forming a cycle. The fluid flow is primarily powered by a pump. This invention avoids the explosion-proof problems caused by direct contact between the heater and the flammable medium, and by heating the low-temperature mixture of oil and refrigerant, the mixture is preheated to a higher temperature before entering the oil-gas separator, thereby improving the oil separation efficiency of the separator. The improved oil separation efficiency of the oil-gas separator can, on the one hand, improve the measurement and control accuracy of the compressor test bench (the method specified in GB / T 5773-2016), and on the other hand, it can still continue to use the existing patent ZL 03102289.8 refrigeration cycle oil circulation flow measuring device and the test device equipped with the device to control and measure the oil level and oil circulation rate with high precision.

[0027] This utility model can achieve at least the following technical effects;

[0028] 1. This invention can be used with flammable and explosive refrigerants, especially for oil circulation rate control and testing systems of flammable and explosive refrigerants in refrigeration systems. It can avoid explosion risks, improve the safety of refrigeration systems, and effectively improve the separation efficiency of oil-gas separators. Correspondingly, this invention is also applicable to non-flammable and weakly flammable refrigerants. This invention can also achieve efficient oil separation and high-precision measurement and control of oil circulation rate even under conditions such as large compressor oil discharge and low exhaust superheat.

[0029] 2. The heating coil of this utility model can be placed externally in the oil-gas separator and oil tank, or it can be built into the oil tank, which increases the contact area between the coil and the oil-gas separator and oil tank, and allows it to directly contact the oil and refrigerant mixture in the oil tank, thereby improving the heating effect.

[0030] 3. This utility model solves the problem of poor oil separation effect of oil-gas separator when the compressor has low exhaust temperature and high oil discharge volume, and improves the control accuracy of oil level and oil circulation rate of compressor testing equipment or other related testing equipment.

[0031] 4. This utility model has a simple structure, is easy to implement, is environmentally friendly, and has high reliability. It can improve the measurement accuracy of oil level and oil circulation rate at low cost.

[0032] 5. The heater involved in this utility model can be placed outside the explosion-proof room, and the heater does not come into direct contact with flammable and explosive refrigerants, which greatly improves the safety of use. Attached Figure Description

[0033] The accompanying drawings 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, these drawings are schematic diagrams not drawn to scale and may not accurately reflect the precise structural or performance characteristics of any of the given embodiments. The drawings should not be construed as limiting or restricting the range of numerical values ​​or properties covered by the exemplary embodiments of the present invention. The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0034] Figure 1 This is a schematic diagram of the structure of the first embodiment of this utility model.

[0035] Figure 2 This is a schematic diagram of the structure of the second embodiment of this utility model.

[0036] Explanation of reference numerals in the attached figures

[0037] Compressor 1

[0038] Heat exchanger 2

[0039] Oil-gas separator 3

[0040] Oil-gas separator heating coil 4

[0041] Oil tank 5

[0042] Oil level gauge 6

[0043] Oil drain valve 7

[0044] Oil circulation rate regulating valve 8

[0045] Oil circulation flow meter 9

[0046] Pump 10

[0047] Heater 11

[0048] Temperature sensor 12. Detailed Implementation

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

[0050] First embodiment;

[0051] refer to Figure 1 As shown, this utility model provides an oil circulation rate control and testing system for flammable and explosive working fluids. The system heats the refrigerant discharged from the compressor 1 before it enters the oil-gas separator 3, and the heat source is located outside the explosion-proof zone or at a specified distance from the heat exchanger.

[0052] Second embodiment;

[0053] Based on the design concept of the first embodiment described above, this utility model provides an oil circulation rate control and testing system for flammable and explosive working fluids, with preferred embodiments including:

[0054] Compressor 1, whose refrigerant outlet is connected to heat exchanger 2, whose refrigerant inlet is connected to;

[0055] Heat exchanger 2 is used for heat exchange between refrigerant and heat exchange medium. The refrigerant after heat exchange is sent to oil-gas separator 3.

[0056] A heat exchange medium heating device, located outside the explosion-proof area or at a specified distance from the heat exchanger 2, is used to heat the heat exchange medium input to the heat exchanger 2 and the heating coil 4 of the oil-gas separator, specifically including:

[0057] Pump 10 has its inlet connected to the heat exchange medium outlet of heat exchanger 2 and the outlet of oil-gas separator heating coil 4, and its outlet is connected to the heat exchange medium inlet of heat exchanger 2 and the inlet of oil-gas separator heating coil 4 via heater 11 and temperature sensor 12.

[0058] The oil-gas separator 3 has its refrigerant outlet connected to the refrigerant inlet of the compressor 1 and its oil outlet connected to the oil inlet of the oil tank 5.

[0059] The oil tank 5 has its oil outlet connected to the oil inlet of the compressor 1 via the oil circulation rate regulating valve 8 and the oil circulation flow meter 9.

[0060] Oil level gauge 6 is arranged in oil tank 5;

[0061] The oil drain valve 7 is formed at the bottom of the oil tank 5.

[0062] The heat exchanger 2 can be a plate type, a shell-and-tube type, or any other device that uses indirect heat exchange. The indirect heating medium is provided with circulation power by a pump and its temperature is increased by a heater.

[0063] Heater 2 can be placed outside the explosion-proof room; the heater itself does not need to be specifically required to be explosion-proof or non-explosion-proof. After being cooled by heat exchange, the heating medium's temperature increases after passing through the heater. It is then pumped into heat exchanger 2 to increase the temperature of the oil-refrigerant mixture discharged from the compressor, while simultaneously improving 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 compressor discharge temperature. The temperature of the oil heating medium can be measured by temperature sensor 12 and its temperature value is controlled by heater 11.

[0064] The heating device of this invention raises the temperature of a mixture of low-superheated refrigerant and oil before it enters an oil-gas separator for efficient separation. The separated oil is stored in an oil tank. There are two main methods for controlling and testing the oil circulation rate: 1. The oil tank contains an oil level gauge 6, and the opening of the return oil regulating valve 8 is adjusted to achieve the set oil level value. 2. The oil circulation rate or oil flow rate is set, and the opening of the return oil regulating valve 8 is adjusted according to the measured value of the oil flow meter 9 to achieve the set oil circulation rate or oil flow rate.

[0065] Third embodiment;

[0066] Based on the design concept of the first embodiment described above, this utility model provides an oil circulation rate control and testing system for flammable and explosive working fluids, with preferred embodiments including:

[0067] Compressor 1, whose refrigerant outlet is connected to heat exchanger 2, whose refrigerant inlet is connected to;

[0068] Heat exchanger 2 is used for heat exchange between refrigerant and heat exchange medium. The refrigerant after heat exchange is sent to oil-gas separator 3.

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

[0070] Pump 10 has its inlet connected to the heat exchange medium outlet of heat exchanger 2, the outlet of heating coil 4 of oil-gas separator, the outlet of heating sleeve 13, and the outlet of heating coil 14 of oil tank cylinder. Its outlet is connected to the heat exchange medium inlet of heat exchanger 2, the inlet of heating coil 4 of oil-gas separator, the inlet of heating sleeve 13, and the inlet of heating coil 14 of oil tank cylinder via heater 11 and temperature sensor 12.

[0071] The oil-gas separator 3 has its refrigerant outlet connected to the refrigerant inlet of the compressor 1, and its oil outlet connected to the oil inlet of the oil tank 5 via a heating sleeve 13.

[0072] The oil tank 5 has its oil outlet connected to the oil inlet of the compressor 1 via the oil circulation rate regulating valve 8 and the oil circulation flow meter 9.

[0073] Oil level gauge 6 is arranged in oil tank 5;

[0074] The oil drain valve 7 is formed at the bottom of the oil tank 5.

[0075] In this embodiment, the oil-gas separator and the oil tank are separate units connected by a heating sleeve 13. The inner tube of the heating sleeve carries the oil and refrigerant mixture flowing from the oil-gas separator to the oil tank. The sandwich between the inner and outer tubes contains an oil heating medium used to heat the oil and refrigerant mixture in the inner tube. Furthermore, a heating coil 14 is added to the oil tank. The heating coil 14 can be externally or internally placed within the oil tank, and it also carries an oil heating medium to heat the oil and refrigerant mixture within the oil tank.

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

[0077] The present invention has been described in detail above through specific embodiments and examples, but these are not intended to limit the present invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A test system for controlling the oil circulation rate of flammable and explosive working fluids, characterized in that: The refrigerant discharged from the compressor (1) is heated before entering the oil-gas separator (3), and the heat source is located outside the explosion-proof area or at a specified distance from the heat exchanger, including: The compressor (1) has its refrigerant outlet connected to the heat exchanger (2), and its refrigerant inlet connected to the heat exchanger (2); Heat exchanger (2) is used for heat exchange between refrigerant and heat exchange medium. The refrigerant after heat exchange is sent to oil-gas separator (3). A heat exchange medium heating device is arranged outside the explosion-proof area or at a specified distance from the heat exchanger (2) for heating the heat exchange medium input to the heat exchanger (2) and the heating coil (4) of the oil-gas separator; The oil-gas separator (3) has its refrigerant outlet connected to the refrigerant inlet of the compressor (1) and its oil outlet connected to the oil inlet of the oil tank (5). The oil tank (5) has its oil outlet connected to the oil inlet of the compressor (1) via an oil circulation rate regulating valve (8) and an oil circulation flow meter (9).

2. The oil circulation rate control and testing system for flammable and explosive working fluids as described in claim 1, characterized in that, The heat exchange medium heating device includes: The pump (10) has its inlet connected to the heat exchange medium outlet of the heat exchanger (2) and the outlet of the oil-gas separator heating coil (4). Its outlet is connected to the heat exchange medium inlet of the heat exchanger (2) and the inlet of the oil-gas separator heating coil (4) via a heater (11) and a temperature sensor (12).

3. The oil circulation rate control and testing system for flammable and explosive working fluids as described in claim 1, characterized in that: The oil outlet of the oil-gas 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 of the input oil tank cylinder heating coil (14).

4. The oil circulation rate control and testing system for flammable and explosive working fluids as described in claim 3, characterized in that, The heat exchange medium heating device includes: The pump (10) has its inlet connected to the heat exchange medium outlet of the heat exchanger (2), the outlet of the oil-gas separator heating coil (4), the outlet of the heating sleeve (13), and the outlet of the oil tank cylinder heating coil (14). Its outlet is connected to the heat exchange medium inlet of the heat exchanger (2), the inlet of the oil-gas separator heating coil (4), the inlet of the heating sleeve (13), and the inlet of the oil tank cylinder heating coil (14) via the heater (11) and the temperature sensor (12).

5. The oil circulation rate control and testing system for flammable and explosive working fluids as described in any one of claims 1-4, characterized in that, Also includes: Oil level gauge (6), which is arranged in oil tank (5); The drain valve (7) is formed at the bottom of the oil tank (5).

Images