Refrigeration system for environmental test chamber

Abstract

The utility model discloses an environmental test chamber refrigerating system, including with the evaporimeter in environmental test chamber successive series oil bath energy accumulator, compressor, condenser, drying filter, and drying filter between evaporimeter have refrigeration road series, and oil bath energy accumulator and drying filter between have with refrigeration road parallel connection's cold bypass, solved the overheating problem of compressor, when the constant low temperature, through the oil bath cold accumulator storage cold bypass refrigerant cold capacity, when the high temperature, release the cold capacity through the oil bath cold accumulator, replace the traditional mode of must sacrifice the refrigeration capacity to cool, compared with traditional protection mode, under the same compressor refrigeration capacity, can realize lower input power and / or faster cooling rate.

Description

Technical Field

[0001] This utility model relates to the field of environmental testing equipment technology, and in particular to a refrigeration system for an environmental testing chamber. Background Technology

[0002] As industrial products face increasingly stringent quality requirements, manufactured products must undergo simulated testing before entering the market. This testing must accurately simulate the product's actual usage conditions. Environmental test chambers can simulate extreme or specific environmental conditions to test a product's performance, reliability, and durability under those conditions. Their core function is to provide a repeatable testing environment for scientific research, industrial production, and quality control by precisely controlling parameters such as temperature, humidity, pressure, and light.

[0003] The temperature range of a test chamber is generally 180℃~-40℃ / -70℃. A traditional test chamber refrigeration system includes a compressor, condenser, and dryer filter connected in series with the evaporator inside the chamber. The dryer filter and evaporator have parallel refrigeration circuits and cold bypass circuits, and hot gas bypass circuits are connected in parallel on both sides of the compressor. However, this type of refrigeration system has the following problems:

[0004] (1) When the test chamber is in a low temperature constant temperature, in order to achieve precise control of the temperature inside the chamber and make the temperature fluctuation ≤ ±0.2℃, the cold and hot offset method is often adopted. That is, the refrigeration circuit of the continuously running refrigeration system is used to cool the inside of the test chamber and is supplemented by electric heating wire connected to the evaporator to achieve a constant low temperature inside the test chamber. However, the cold and hot offset leads to energy waste, significant loss of refrigeration capacity, and low efficiency. Alternatively, the opening and closing ratio of the solenoid valves on the cold bypass and hot gas bypass is controlled by PID and duty cycle method to control whether the refrigerant passes through the evaporator and achieve 0~100% adjustment of refrigeration capacity. The low temperature and low pressure refrigerant directly flows back to the compressor, which can easily lead to compressor frost and liquid refrigerant liquid slugging (risk of mechanical damage), affecting the life of the equipment. Although the hot gas bypass can be opened to mix high temperature gas to alleviate the problem, precise coordination control is required, and the system complexity is high.

[0005] (2) When the test chamber is cooled down in the high temperature range (such as above 100°C), the refrigerant is too hot when it passes through the evaporator and is not cooled enough when it passes through the compressor motor, which can easily trigger an overheat alarm. If the refrigeration circuit is opened at 50~80% and the cold bypass is opened at 20~50%, the refrigerant is diverted by the cold bypass. Although the compressor overheat protection problem is solved, it also leads to a loss of cooling capacity and relatively low refrigeration efficiency.

[0006] Therefore, there is an urgent need for an energy-saving solution that balances efficient cooling, temperature stability, and equipment protection. Utility Model Content

[0007] In response to the problems of existing environmental test chamber refrigeration systems, such as energy waste due to cold-heat offsetting during low-temperature constant temperature operation, compressor frost or even liquid slugging caused by fully opening the cold bypass allowing refrigerant to enter the compressor directly without passing through the evaporator, and inability to simultaneously address compressor overheating and cooling capacity loss during high-temperature cooling, the applicant proposes a rationally structured environmental test chamber refrigeration system. This system achieves precise temperature control through the coordinated operation of the refrigeration circuit, cold bypass, hot gas bypass, and oil bath accumulator, optimizes the refrigerant circulation path and compressor return gas temperature management, saves energy, improves refrigeration efficiency, and prevents compressor failure.

[0008] The technical solution adopted by this utility model and the beneficial effects it achieves are as follows:

[0009] A refrigeration system for an environmental test chamber includes an oil bath accumulator, a compressor, a condenser, and a dryer filter connected in series with an evaporator inside the environmental test chamber. A refrigeration circuit is connected in series between the evaporator and the dryer filter, and a cold bypass is connected in parallel with the refrigeration circuit between the oil bath accumulator and the dryer filter.

[0010] As a further improvement to the above technical solution:

[0011] The oil bath accumulator has a cold bypass pipe and a heat exchanger inside.

[0012] The refrigeration circuit includes a main refrigeration solenoid valve and a capillary tube connected in series.

[0013] The cold bypass includes a cold circuit solenoid valve and a capillary tube connected in series.

[0014] A hot gas bypass is connected in parallel between the oil bath accumulator and the condenser. The hot gas bypass includes a hot circuit solenoid valve and a capillary tube.

[0015] This invention solves the problem of compressor overheating. When the temperature is constant, the cold energy of the refrigerant in the cold bypass is stored in an oil bath accumulator. When the temperature is high, the cold energy is released through the oil bath accumulator. This replaces the traditional method of sacrificing cooling capacity to cool down. Compared with the traditional protection mode, it can achieve lower input power and / or faster cooling rate under the same compressor cooling capacity. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] In the diagram: 1. Compressor; 2. Condenser; 3. Dryer filter; 4. Environmental test chamber; 5. Electric heating wire; 6. Evaporator; 7. Main refrigeration solenoid valve; 8. Cold circuit solenoid valve; 9. Hot circuit solenoid valve; 10. Capillary tube; 11. Oil bath accumulator. Detailed Implementation

[0018] The specific embodiments of this utility model are described below with reference to the accompanying drawings.

[0019] like Figure 1 As shown, the refrigeration system of the environmental test chamber provided by this utility model includes an oil bath accumulator 11, a compressor 1, a condenser 2, and a dryer filter 3 connected in series with the evaporator 6 inside the environmental test chamber 4. The evaporator 6 achieves refrigeration by absorbing heat and evaporating a low-temperature, low-pressure liquid. The evaporator 6 is connected to an electric heating wire 5 for antifreeze and defrosting of the evaporator 6. The compressor 1 is used to compress the refrigerant and form a high-temperature, high-pressure gas. The condenser 2 is used to cool the high-temperature gas output by the compressor 1 into a low-temperature, high-pressure liquid. The dryer filter 3 is used to remove moisture and impurities from the refrigerant. The oil bath accumulator 11 has a cold bypass pipe and a heat exchanger (not shown in the figure). The medium inside the oil bath accumulator 11 is silicone oil, heat transfer oil, etc., which are resistant to high and low temperatures.

[0020] A refrigeration circuit is connected in series between the evaporator 6 and the dryer filter 3. This circuit includes a main refrigeration solenoid valve 7 and a capillary tube 10 connected in series. The opening and closing of the main refrigeration solenoid valve 7 is controlled by a PID controller to regulate the amount of refrigerant entering the evaporator 6 via the refrigeration circuit. A cold bypass is connected in parallel with the refrigeration circuit between the oil bath accumulator 11 and the dryer filter 3. This bypass includes a cold circuit solenoid valve 8 and a capillary tube 10 connected in series. Controlling the opening and closing of the cold circuit solenoid valve 8 allows the low-temperature refrigerant to be directly returned to the compressor 1, preventing overheating. A hot gas bypass is connected in parallel between the oil bath accumulator 11 and the condenser 2. This bypass includes a hot circuit solenoid valve 9 and a capillary tube 10. When the test chamber is at a constant low temperature, the cold bypass, once opened, can introduce low-temperature refrigerant into the oil bath accumulator 11, lowering the temperature of the silicone oil inside and storing energy. This does not affect the cooling capacity of the equipment.

[0021] When this system is running, if the environmental test chamber 4 is at a constant low temperature, the required cooling capacity is small. The compressor 1 compresses the refrigerant into a high-temperature, high-pressure gas. The high-temperature gas is cooled by the condenser 2 into a room-temperature, high-pressure liquid. Moisture and impurities are removed by the dryer filter 3. Based on the temperature inside the test chamber, the opening and closing ratios of the main refrigeration solenoid valve 7 and the cold circuit solenoid valve 8 are adjusted in real-time using PID control. Part of the refrigerant passes through the capillary tube 10 in the refrigeration circuit, becoming a low-temperature, low-pressure liquid. After passing through the evaporator 6, it becomes a room-temperature, low-pressure gas, and then returns to the compressor 1 through the suction pipe to achieve refrigerant circulation. The remaining refrigerant passes through… After the capillary tube 10 of the cold bypass, the refrigerant bypasses the evaporator 6 and directly enters the oil bath accumulator 11. The refrigerant transfers its cooling capacity to the silicone oil inside the oil bath accumulator 11, thereby lowering the temperature of the silicone oil and storing energy. The refrigerant then enters the compressor 1. The cold storage process of the oil bath accumulator 11 does not affect the cooling capacity of the equipment. The temperature fluctuation in the environmental test chamber 4 is ≤ ±0.2℃, maintaining a constant low temperature. The hot circuit solenoid valve 9 of the hot gas bypass opens synchronously, and the high-temperature and high-pressure gas discharged from the compressor 1 enters the suction pipe of the compressor 1. After mixing with the low-temperature and low-pressure refrigerant input from the cold bypass, it enters the compressor 1, avoiding overheating of the compressor 1 and liquid slugging.

[0022] When the test chamber needs to be cooled down at high temperatures, there is a high demand for cooling. The main cooling solenoid valve 7 is kept 100% open, and all the refrigerant flows through the evaporator 6 to provide the maximum cooling capacity. The high-temperature return gas output from the evaporator 6 enters the oil bath accumulator 11, where the stored silicone oil exchanges heat with the high-temperature return gas and cools it, preventing it from overheating after entering the compressor 1. This can fully cool the internal motor of the compressor 1. Since there is almost no loss of cooling capacity, the input power required for the compressor 1 of the same horsepower to output the same cooling capacity (such as to achieve the same cooling rate) is reduced, or a faster cooling rate can be achieved with the same input power, thus achieving energy saving.

[0023] The above description is an explanation of this utility model and not a limitation thereof. Without departing from the spirit of this utility model, any form of modification can be made to this utility model. This utility model describes a single-stage energy-saving method, and the refrigeration system of this utility model is also applicable to cascade units.

Claims

1. A refrigeration system for an environmental test chamber, characterized in that: The system includes an oil bath accumulator (11), a compressor (1), a condenser (2), and a dryer filter (3) connected in series with the evaporator (6) in the environmental test chamber (4). A refrigeration circuit is connected in series between the evaporator (6) and the dryer filter (3), and a cold bypass is connected in parallel with the refrigeration circuit between the oil bath accumulator (11) and the dryer filter (3).

2. The environmental test chamber refrigeration system according to claim 1, characterized in that: The oil bath accumulator (11) has a cold bypass pipe and a heat exchanger inside.

3. The environmental test chamber refrigeration system according to claim 1, characterized in that: The refrigeration circuit includes a main refrigeration solenoid valve (7) and a capillary tube (10) connected in series.

4. The refrigeration system of the environmental test chamber according to claim 1, characterized in that: The cold bypass includes a cold circuit solenoid valve (8) and a capillary tube (10) connected in series.

5. The refrigeration system of the environmental test chamber according to claim 1, characterized in that: A hot gas bypass is connected in parallel between the oil bath accumulator (11) and the condenser (2). The hot gas bypass includes a hot circuit solenoid valve (9) and a capillary tube (10).

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