Nitrogen cooling device with oil cooler

Abstract

The utility model discloses a nitrogen cooling device with an oil cooler, which comprises a double-screw compressor, an oil-gas separator, a condenser, an expansion valve and an evaporator, an exhaust port of the compressor is connected with an oil gas inlet through a pipeline, an oil gas outlet is connected with the condenser, the condenser is connected with the expansion valve, the expansion valve is connected with a refrigerant inlet of the evaporator, and the evaporator is connected with a refrigerant outlet of the oil cooler. A refrigerant outlet of the evaporator is connected with an air suction port of the compressor, an oil cooler and an oil temperature control valve are arranged on a pipeline between an oil separation outlet of the oil separator and an oil return port of the compressor, and an oil separation outlet of the oil-gas separator is respectively connected with an oil cooling inlet of the oil cooler and a hot oil inlet of the oil temperature control valve through pipelines. An oil cooling outlet of the oil cooler is connected with a cold oil inlet of the oil temperature control valve, and a mixed oil outlet of the oil temperature control valve is connected with an oil return opening of the double-screw compressor. The low-temperature nitrogen output device can output low-temperature nitrogen with the lowest temperature of-30 DEG C, and is simple in structure, stable in operation and low in failure rate.

Description

Technical Field

[0001] The utility model belongs to refrigeration equipment, in particular to a nitrogen cooling device for fire prevention and extinguishing used in underground coal mine environments. Background Art

[0002] At present, nitrogen at room temperature has been widely used in coal mine fire prevention and extinguishing. However, for coal seams prone to spontaneous combustion, the introduction of cooled nitrogen can effectively reduce the temperature of the coal seams and prevent spontaneous combustion, which is better than the fire prevention and extinguishing effect of nitrogen at room temperature.

[0003] However, the existing nitrogen cooling equipment has a complex structure, many faults during operation, and complex maintenance. For example, Patent 1, a high temperature environment fire prevention and extinguishing nitrogen cooling device, patent number CN 101988771B, has multiple evaporation systems, adopts multi-stage evaporation, and a step-by-step cooling refrigeration method; Patent 2, a nitrogen cooling device, patent number CN 209101625U, although it adopts single-stage compression, is equipped with an economizer. Because the economizer needs to be equipped with an expansion valve, part of the refrigerant evaporates and refrigerates in the economizer, making the other part of the refrigerant supercooled. The economizer itself is also an evaporation system, so the whole system includes two evaporation systems, a nitrogen cooling evaporation system and an economizer. When the equipment has two or more evaporation systems, if one of the evaporation systems fails, it will affect the overall operation of the equipment, so the failure rate is high. Summary of the invention

[0004] The utility model aims to provide a nitrogen cooling device with an oil cooler, the system comprising a twin-screw compressor, an oil-gas separator, a condenser, an expansion valve, and an evaporator. The twin-screw compressor has a compressor air intake, a compressor exhaust, and a compressor oil return port. The oil-gas separator has an oil inlet, an oil outlet, and an oil outlet. The evaporator has a refrigerant inlet, a refrigerant outlet, a nitrogen inlet, and a nitrogen outlet. The compressor exhaust port is connected to the oil inlet via a pipeline, the oil outlet is connected to the condenser, the condenser is connected to the expansion valve, the expansion valve is connected to the refrigerant inlet of the evaporator, the refrigerant outlet of the evaporator is connected to the compressor air intake, and the oil outlet of the oil separator is connected to the nitrogen inlet. An oil cooler and an oil temperature control valve are installed on the pipeline between the oil port and the oil return port of the compressor. The oil cooler has an oil cooling inlet and an oil cooling outlet. The oil temperature control valve has a cold oil inlet, a hot oil inlet and a mixed oil outlet. The oil temperature control valve has a built-in temperature sensing element and a valve core. The temperature sensing element generates a volume change by sensing the change in oil temperature and then controls the position of the valve core to adjust the flow rate of cold and hot oil flowing in to achieve temperature control. The oil outlet of the oil-gas separator is connected to the oil cooling inlet of the oil cooler and the hot oil inlet of the oil temperature control valve through pipelines respectively. The oil cooling outlet of the oil cooler is connected to the cold oil inlet of the oil temperature control valve, and the mixed oil outlet of the oil temperature control valve is connected to the oil return port of the twin-screw compressor.

[0005] Furthermore, the oil cooler adopts an air-cooled oil cooler, and the condenser adopts an air-cooled condenser.

[0006] The beneficial effects of the utility model are as follows: the nitrogen cooling device with an oil cooler of the utility model controls the temperature of the lubricating oil through the oil cooler and the oil temperature control valve, which not only meets the lubrication of the twin-screw compressor but also reduces the exhaust temperature. The equipment can output low-temperature nitrogen with a minimum of -30°C during operation, has a simple structure, stable operation and a low failure rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a structural schematic diagram of the utility model.

[0008] In the figure: twin-screw compressor 1, oil-gas separator 2, condenser 3, oil cooler 4; oil temperature control valve 5, expansion valve 6, evaporator 7, compressor suction port 101, compressor oil return port 102, compressor exhaust port 103, oil separator air inlet 201, oil separator air outlet 202, oil separator oil outlet 203, oil cooling outlet 401, oil cooling inlet 402, cold oil inlet 501, hot oil inlet 502, mixed oil outlet 503, refrigerant inlet 701, nitrogen inlet 702, nitrogen outlet 703, refrigerant outlet 704. DETAILED DESCRIPTION

[0009] The technical solution of the utility model is further described below in conjunction with the embodiments and drawings.

[0010] like Figure 1As shown, the utility model is a nitrogen cooling device with an oil cooler, comprising a twin-screw compressor 1, an oil-gas separator 2, a condenser 3, an expansion valve 6, and an evaporator 7. The twin-screw compressor 1 has a compressor air intake 101, a compressor exhaust 103, and a compressor oil return port 102. The oil-gas separator 2 has an oil separator air inlet 201, an oil separator air outlet 202, and an oil separator oil outlet 203. The evaporator 7 has a refrigerant inlet 701, a refrigerant outlet 704, a nitrogen inlet 702, and a nitrogen outlet 703. The compressor exhaust 103 is connected to the oil separator air inlet 201 through a pipeline, and the oil separator air outlet 202 is connected to the condenser 3. The condenser 3 is connected to the expansion valve 6. The expansion valve 6 is connected to the refrigerant inlet 701 of the evaporator 7, and the refrigerant outlet 704 of the evaporator is connected to the compressor air intake 101. An oil cooler 4 and an oil temperature control valve 5 are installed on the pipeline between the oil outlet 203 of the oil-gas separator 2 and the compressor oil return port 102. The oil cooler 4 has an oil cooling inlet 402 and an oil cooling outlet 401. The oil temperature control valve 5 has a cold oil inlet 501, a hot oil inlet 502 and a mixed oil outlet 503. The oil temperature control valve 5 has a built-in temperature sensing element and a valve core. The temperature sensing element generates a volume change by sensing the oil temperature change and then controls the valve core position to adjust the flow rate of the cold and hot oil flowing in to achieve temperature control. The oil outlet 203 is connected to the oil cooling inlet 402 and the hot oil inlet 502 of the oil temperature control valve 5 through a pipeline respectively. The oil cooling outlet 401 of the oil cooler 4 is connected to the cold oil inlet 501 of the oil temperature control valve 5, and the mixed oil outlet 503 is connected to the compressor oil return port 102.

[0011] Furthermore, the oil cooler 4 is an air-cooled oil cooler, and the condenser 3 is an air-cooled condenser.

[0012] Embodiment 1: When working, the twin-screw compressor 1 sucks in gaseous refrigerant from the compressor suction port 101. The oil-containing gaseous refrigerant compressed by the compressor is transported from the compressor exhaust port 103 to the oil separator inlet 201 through the pipeline. The oil-containing gaseous refrigerant is separated into compressed gaseous refrigerant and liquid lubricating oil in the oil-gas separator 2. The compressed gaseous refrigerant is cooled in the condenser 3 and becomes liquid refrigerant. Then, it is transported to the expansion valve 6 through the pipeline to become low-temperature refrigerant after throttling and reducing pressure. Then, it enters the refrigerant inlet 701 of the evaporator 7 through the pipeline. The nitrogen to be cooled is passed through the nitrogen gas separator 2. The nitrogen enters the evaporator 7 through the inlet 702. In the evaporator 7, the nitrogen exchanges heat with the low-temperature refrigerant. The nitrogen is cooled to about -30°C. The cooled nitrogen is output through the nitrogen outlet 703. The low-temperature refrigerant in the evaporator 7 is completely gasified after absorbing heat and is output to the compressor suction port 101 through the refrigerant outlet 704. The liquid lubricating oil separated in the oil-gas separator 2 is transported from the oil separator outlet 203 through the pipeline to the hot oil inlet 502 of the oil temperature control valve 5 and the oil cooling inlet 402 of the oil cooler 4, and enters the liquid lubricating oil in the oil cooler 4. After the lubricating oil is cooled, it is transported to the cold oil inlet 501 of the oil temperature control valve 5 through the oil cooling outlet 401. The temperature sensing element in the oil temperature control valve 5 senses the change in oil temperature and generates a volume change to control the valve core position, thereby adjusting the oil flow entering the hot oil inlet 502 and the cold oil inlet 501, so as to achieve the purpose of controlling the oil temperature at the mixed oil outlet 503. When the oil temperature at the hot oil inlet 502 is lower than 43°C, the temperature sensing element in the oil temperature control valve 5 will close the cold oil inlet 501 and fully open the hot oil inlet 502. When the oil temperature is higher than 49°C, the temperature sensing element in the oil temperature control valve 5 will close the hot oil inlet 502 and fully open the cold oil inlet 501. When the oil temperature at the hot oil inlet 502 is between 43°C and 49°C, the temperature sensing element in the oil temperature control valve 5 partially opens the cold oil inlet 501 and the hot oil inlet 502. The liquid lubricating oil is temperature-controlled by the oil temperature control valve 5 and then transported to the compressor oil return port 102 through the mixed oil outlet 503, thereby achieving the functions of lubrication, sealing and reducing the exhaust temperature of the twin-screw compressor. This cycle achieves the purpose of nitrogen cooling.

[0013] Example 2: It is basically the same as Example 1, except that the oil cooler 4 adopts an air-cooled oil cooler and the condenser 3 adopts an air-cooled condenser. Since the air cooling method eliminates the need for a circulating water pump system and a device to prevent water scaling compared to the water cooling method, the system is simple, stable and has a low failure rate.

Claims

1. A nitrogen cooling device with an oil cooler, comprising a twin-screw compressor (1), an oil-gas separator (2), a condenser (3), an expansion valve (6), and an evaporator (7), wherein the twin-screw compressor (1) has a compressor air intake port (101), a compressor air exhaust port (103), and a compressor oil return port (102), the oil-gas separator (2) has an oil inlet port (201), an oil outlet port (202), and an oil outlet port (203), and the evaporator (7) has a refrigerant inlet port (701), a refrigerant outlet port (704), a nitrogen inlet port (702), and a nitrogen outlet port (703), characterized in that: The compressor exhaust port (103) is connected to the oil separator air inlet (201) via a pipeline, the oil separator air outlet (202) is connected to the condenser (3), the condenser (3) is connected to the expansion valve (6), the expansion valve (6) is connected to the refrigerant inlet (701) of the evaporator (7), the refrigerant outlet (704) of the evaporator is connected to the compressor air intake port (101), and an oil cooler (4) and an oil temperature control valve (5) are installed on the pipeline between the oil separator outlet (203) of the oil-gas separator (2) and the compressor oil return port (102). The oil cooler (4) has an oil cooling inlet (402), an oil cooling outlet (401), and an oil temperature control valve (5). 5) has a cold oil inlet (501), a hot oil inlet (502) and a mixed oil outlet (503); the oil temperature control valve (5) has a built-in temperature sensing element and a valve core; the temperature sensing element senses the change in oil temperature to generate a volume change and then controls the position of the valve core to adjust the flow of cold and hot oil flowing in to achieve temperature control; the oil outlet (203) is connected to the oil cooling inlet (402) and the hot oil inlet (502) of the oil temperature control valve (5) through pipelines, the oil cooling outlet (401) of the oil cooler (4) is connected to the cold oil inlet (501) of the oil temperature control valve (5), and the mixed oil outlet (503) is connected to the compressor oil return port (102).

2. A nitrogen cooling device with an oil cooler according to claim 1, characterized in that: The oil cooler (4) is an air-cooled oil cooler, and the condenser (3) is an air-cooled condenser.

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