Mine-used explosion-proof refrigerating unit with compact layout of oil separation system

Abstract

An oil separation system compact layout mine explosion-proof refrigeration unit, including screw compressor, oil cooler, economizer, condenser and evaporator, also includes a series of first oil separator and second oil separator, two oil separators preferably vertical structure, close to and parallel arrangement, can replace the bulky horizontal oil separator, make full use of mine roadway vertical space, significantly reduce the equipment volume. The condenser refrigerant output end is divided into three, three refrigerant through the synergistic heat exchange between the economizer, evaporator and oil cooler, can be supercooled treatment of refrigerant working fluid, reduce the evaporation of liquid and oil cooling liquid gas flash, strengthen the evaporation heat transfer and oil cooling heat transfer effect, ensure the temperature stability of lubricating oil, reduce the refrigeration unit with liquid. It can take into account the underground narrow roadway transport and installation, avoid the equipment module in the process of moving collision, improve the working efficiency of refrigeration unit, meet the needs of various small mine mining.

Description

Technical Field

[0001] This utility model relates to explosion-proof refrigeration equipment for local cooling in mines, specifically an explosion-proof refrigeration unit for mining with a compact layout of an oil separation system. Background Technology

[0002] As shallow mineral resources are gradually depleted, mining operations in my country are increasingly shifting towards deeper layers, with the number of wells exceeding 1,000 meters increasing year by year. However, with the continuous increase in mining depth, mine temperatures are also rising, making underground heat hazards more prominent. Due to the presence of multiple heat sources in deep mines, including heat dissipation from high-temperature surrounding rock, air compression heat, mechanical equipment heat dissipation, and oxidation heat release, the air temperature in underground mining working layers and electromechanical chambers rises significantly, seriously affecting the safe operation of mine equipment and the physical and mental health of miners. How to effectively manage mine heat hazards has always been a research topic for those skilled in the art.

[0003] Mine heat hazard control has gone through several stages, and although some progress has been made, some shortcomings still exist. Traditional mine cooling systems mainly use centralized refrigeration units, which require large chiller units, cooling towers, water pumps, pipelines, valves, and other auxiliary facilities. Their structure is relatively cumbersome and complex, inflexible in movement and use, and results in significant loss of cooling energy and water resources. They are also less effective in mining faces with particularly severe heat hazards and are difficult to adapt to the requirements of the narrow underground space.

[0004] To address the aforementioned problems, those skilled in the art have designed a modular screw compressor refrigeration unit for localized cooling in mines. This unit combines a screw compressor, condenser, and supporting components into a movable compressor module, and combines an evaporator and its supporting components into a movable evaporator module. The two modules are connected by an adjustable metal transmission hose. This allows for the combined use of the compressor module and evaporator module according to different operating conditions, facilitating underground installation and transportation. The evaporator module can be moved to the area requiring the most cooling, thus meeting the localized cooling needs of mines with severe heat hazards.

[0005] However, many deep mine shaft yards or chambers are only 3-5 meters wide, and some construction sites are even less than 2.5 meters high. Furthermore, most underground roadways are winding and tortuous, making it difficult for even modular screw compressor refrigeration units to pass through. In particular, compressor modules integrated with oil separators cannot pass directly and require modifications to the roadway structure, disassembly for transport, and on-site assembly. This not only makes transportation and installation time-consuming and labor-intensive, but also increases the risk of equipment damage during movement and reduces the efficiency of the refrigeration units. How to further reduce the size of modular underground refrigeration units while meeting the size requirements of mine cages and roadways is a pressing issue that needs to be addressed. Summary of the Invention

[0006] The purpose of this utility model is to provide a mine explosion-proof refrigeration unit with a compact layout for oil separation system, which can take into account transportation and installation in narrow underground tunnels, effectively avoid equipment collisions during movement, improve the working efficiency of the refrigeration unit, and better meet the mining needs of various small mines.

[0007] To achieve the above objectives, the oil separation system of this utility model is designed with a compact layout for mining explosion-proof refrigeration units, including a screw compressor, an economizer, a condenser, and an evaporator connected by pipes and valves. Its special feature is that: It also includes a primary oil separator and a secondary oil separator connected in series. The discharge port of the screw compressor is connected to the mixed working fluid inlet of the primary oil separator, the refrigerant outlet of the primary oil separator is connected to the mixed working fluid inlet of the secondary oil separator, and the refrigerant outlet of the secondary oil separator is connected to the refrigerant input end of the condenser. The oil outlet of the primary oil separator is connected to the hot oil inlet of the oil cooler through a coarse oil filter, and the cold oil outlet of the oil cooler is connected to the shaft seals, bearings, and oil return ports of the screw compressor through an oil pump and a fine oil filter. The oil outlet of the secondary oil separator is connected to the oil return port of the screw compressor.

[0008] The refrigerant output of the condenser is divided into three paths: the first path is connected to the high-pressure side inlet of the economizer, the high-pressure side outlet of the economizer is connected to the refrigerant inlet of the evaporator through the evaporator liquid supply pipe assembly, and the refrigerant outlet of the evaporator is connected to the suction port of the screw compressor; the second path is connected to the low-pressure side inlet of the economizer through the economizer liquid supply pipe assembly, and the low-pressure side outlet of the economizer is connected to the economizer gas replenishment port of the screw compressor; the third path is connected to the refrigerant inlet of the oil cooler through the oil cooler liquid supply pipe assembly, and the refrigerant outlet of the oil cooler is connected to the suction port of the screw compressor.

[0009] As a preferred embodiment, the primary and secondary oil separators are arranged vertically, side by side. This arrangement maximizes the use of vertical space and significantly reduces the lateral space occupied, thereby substantially reducing the overall volume of the mine explosion-proof refrigeration unit. It also effectively prevents collisions between equipment modules during movement and facilitates transportation and installation in narrow underground tunnels.

[0010] Furthermore, the main separation component inside the primary oil separator is a wire mesh demister, which significantly reduces the oil content in the screw compressor exhaust, ensuring that the oil content in the exhaust before entering the secondary oil separator is below 1500 ppm; the main separation component inside the secondary oil separator is a high-efficiency oil filter element, which ultimately reduces the oil content in the exhaust from the primary oil separator to within 5 ppm, thereby ensuring efficient separation of lubricating oil.

[0011] Furthermore, the secondary oil separator has two oil outlets: one for natural flow and the other for the high-efficiency filter element. Both the natural flow outlet and the high-efficiency filter element outlet are connected to the screw compressor's oil return port via return oil pipelines. This allows this portion of the lubricating oil to be returned to the screw compressor in a timely manner, preventing excessive accumulation of lubricating oil in the oil separator, improving the oil separator's processing efficiency, and simultaneously reducing the oil storage capacity of the screw compressor.

[0012] As a preferred option, the oil cooler and economizer employ plate-and-shell heat exchangers. On one hand, plate-and-shell heat exchangers are small in size, allowing for a compact overall structure and facilitating transportation and installation of the unit within limited space in the mine. On the other hand, compared to plate heat exchangers, plate-and-shell heat exchangers are structurally more stable, better suited to the mine environment requiring frequent lifting and transportation, and have a lower probability of leakage failures. They also improve the cooling capacity and COP of the refrigeration unit, and the subcooling of the evaporator supply pipe assembly significantly enhances the heat exchange effect of the evaporator, reducing liquid carryover in the refrigeration unit.

[0013] Furthermore, the cold oil outlet of the oil cooler is directly connected to the oil return port of the screw compressor via a return oil pipeline. This allows for two main benefits: firstly, forced oil return via the oil pump and oil filter ensures that lubricating oil meeting cleanliness requirements fills and lubricates all parts of the screw compressor, guaranteeing safe and reliable start-up of the refrigeration unit; secondly, the oil pump can be shut off after the refrigeration unit is running normally, allowing for oil supply balance through the unit's own pressure differential, thereby saving on operating costs.

[0014] Furthermore, the oil coarse filter adopts a liquid path filtration structure, with its inlet and outlet diameters larger than the diameter of the connected pipeline. This allows the liquid path structure to significantly reduce its size while meeting the requirements for coarse filtration of lubricating oil, and its large-diameter structure also provides greater flow capacity and reduces pipeline pressure loss.

[0015] Furthermore, the evaporator supply pipe assembly and the oil cooler supply pipe assembly are composed of a shut-off valve, an electric regulating valve, and a throttle valve connected in series, while the economizer supply pipe assembly is composed of an electric regulating valve and a throttle valve connected in series. Combining the electric regulating valve and the throttle valve allows for convenient remote control of the opening, closing, and opening degree of the electric regulating valve, and coordinates with the corresponding throttle valve to improve the throttling effect.

[0016] The advantages of this invention are as follows: The oil separation system of the mine explosion-proof refrigeration unit is optimized by splitting the original single horizontal oil separator into a smaller primary oil separator and a secondary oil separator, arranged in series. This not only effectively reduces the volume of the combined oil separator but also reduces the amount of lubricating oil required for the screw compressor. While ensuring effective oil separation, the overall footprint of the refrigeration unit is reduced, making it suitable for transportation and installation in narrow underground tunnels. In particular, when the two oil separators are arranged vertically and side-by-side, they can be combined with the screw compressor to form a more compact module, further reducing the footprint and height of the entire mine explosion-proof refrigeration unit. This makes it easier to move and arrange in narrow mine tunnels, reducing collisions during transport. It is also more suitable for small mine operations, eliminating the need to expand the cage and tunnel dimensions due to size issues. Meanwhile, the refrigerant output of the condenser is divided into three paths. Through the synergistic heat exchange between the economizer, evaporator and oil cooler, the refrigerant working fluid can be subcooled, reducing gas flashing in the evaporation and oil cooling liquid supply, enhancing the heat exchange effects of evaporation and oil cooling, ensuring stable lubricating oil temperature, reducing liquid carryover in the refrigeration unit, and thus improving the refrigeration capacity and COP of the refrigeration unit. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the connection structure of a compact layout mining explosion-proof refrigeration unit for an oil separation system.

[0018] The components in the diagram are labeled as follows: 1. Screw compressor; 2. Explosion-proof high-pressure three-phase asynchronous motor; 3. First-stage oil separator; 4. Second-stage oil separator; 5. Oil fine filter; 6. Oil coarse filter; 7. Oil pump; 8. Explosion-proof three-phase asynchronous motor; 9. Oil cooler; 10. Oil cooler supply pipe assembly; 11. Economizer; 12. Economizer supply pipe assembly; 13. Evaporator supply pipe assembly; 14. Evaporator; 15. Condenser. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but these embodiments should not be construed as limiting the present invention.

[0020] like Figure 1The illustrated explosion-proof refrigeration unit for mining applications features a compact oil separation system. It includes a screw compressor 1, an economizer 11, a condenser 15, and an evaporator 14, all connected by pipes and valves. The screw compressor 1 is connected to an explosion-proof high-voltage three-phase asynchronous motor 2 via a coupling, and is driven by the motor. The system also includes a primary oil separator 3 and a secondary oil separator 4 connected in series. The exhaust port of the screw compressor 1 is connected to the mixed refrigerant inlet of the primary oil separator 3, the refrigerant outlet of the primary oil separator 3 is connected to the mixed refrigerant inlet of the secondary oil separator 4, and the refrigerant outlet of the secondary oil separator 4 is connected to the refrigerant input of the condenser 15.

[0021] The oil outlet of the primary oil separator 3 is connected to the hot oil inlet of the oil cooler 9 through the coarse oil filter 6. The cold oil outlet of the oil cooler 9 is connected to the shaft seals, bearings and oil return ports of the screw compressor 1 through the oil pump 7 and the fine oil filter 5. The oil pump 7 is driven by the explosion-proof three-phase asynchronous motor 8. The oil outlet of the secondary oil separator 4 is connected to the oil return port of the screw compressor 1.

[0022] The refrigerant output of condenser 15 is divided into three paths: the first path is connected to the high-pressure side inlet of economizer 11, the high-pressure side outlet of economizer 11 is connected to the refrigerant inlet of evaporator 14 through evaporator liquid supply pipe assembly 13, and the refrigerant outlet of evaporator 14 is connected to the suction port of screw compressor 1; the second path is connected to the low-pressure side inlet of economizer 11 through economizer liquid supply pipe assembly 12, and the low-pressure side outlet of economizer 11 is connected to the economizer gas replenishment port of screw compressor 1; the third path is connected to the refrigerant inlet of oil cooler 9 through oil cooler liquid supply pipe assembly 10, and the refrigerant outlet of oil cooler 9 is connected to the suction port of screw compressor 1.

[0023] More specifically: The primary oil separator 3 and the secondary oil separator 4 adopt a vertical structure, arranged side-by-side adjacent to each other. This allows them to replace bulky horizontal oil separators, utilizing the narrow vertical space of the downhole tunnel for a compact arrangement, significantly reducing the equipment's volume and preventing collisions during movement. Furthermore, the main separation component inside the primary oil separator 3 uses a wire mesh demister to filter the oil content in the exhaust gas of the screw compressor 1 to below 1500 ppm; the main separation component inside the secondary oil separator 4 uses a high-efficiency oil filter element to filter the oil content in the exhaust gas from the primary oil separator to below 5 ppm, ensuring efficient separation of lubricating oil. The secondary oil separator 4 has two oil outlets: a natural flow outlet 4a and a high-efficiency filter outlet 4b. Both outlets are connected to the return oil port of the screw compressor 1 via return oil pipelines. This allows some of the lubricating oil to be returned to the screw compressor 1 in stages, preventing excessive accumulation of lubricating oil in the oil separator and reducing the oil storage capacity of the screw compressor 1. Furthermore, because the primary oil separator 3 and the secondary oil separator 4 are relatively small, the main oil injection channel of the screw compressor 1 can be designed to be smaller. For example, instead of the conventional 4.1mm diameter nozzle, a small-channel nozzle with a 2.3mm diameter can be used, which can reduce the lubricating oil circulation rate from 100L / min to 40L / min, thereby effectively reducing the amount of lubricating oil required for unit operation.

[0024] In this embodiment, the oil cooler 9 and the economizer 11 employ plate-and-shell heat exchangers. Plate-and-shell heat exchangers are characterized by their small size and compact structure, facilitating the transportation and installation of the unit in the confined spaces of a mine. Moreover, compared to plate heat exchangers, plate-and-shell heat exchangers are structurally more stable, better suited to the mine environment requiring frequent lifting and transportation, and have a lower probability of leakage failures. Simultaneously, they can increase the cooling capacity and COP of the refrigeration unit, significantly improve the heat exchange effect of the evaporator, and reduce liquid carryover in the refrigeration unit.

[0025] In this embodiment, the cold oil outlet of the oil cooler 9 is also directly connected to the oil return port of the screw compressor 1 via a return oil pipeline. After the screw compressor 1 is running normally, the oil pump 7 can be turned off, and oil supply balance can be achieved through the pressure difference of the refrigeration unit itself, thereby saving the operating cost of the refrigeration unit.

[0026] In this embodiment, the oil coarse filter 6 adopts a liquid path filtration structure, and the diameter of its inlet and outlet is larger than the diameter of the pipeline connected to it. The liquid path structure can significantly reduce its size while meeting the requirements of lubricating oil coarse filtration, and its large diameter structure can also provide more flow capacity and reduce pipeline pressure loss.

[0027] In this embodiment, the evaporator supply pipe assembly 13 and the oil cooler supply pipe assembly 10 are constructed by connecting a shut-off valve, an electric regulating valve, and a throttle valve in series, while the economizer supply pipe assembly 12 is constructed by connecting an electric regulating valve and a throttle valve in series. Combining the electric regulating valve and the throttle valve allows for convenient remote control of the opening, closing, and opening degree of the electric regulating valve, and coordinates with the corresponding throttle valve to improve the throttling effect. The shut-off valve's main function is to close the corresponding pipeline during maintenance and repair.

[0028] In this embodiment, the evaporator 14 adopts an air-cooled structure. The connecting pipes between its refrigerant inlet and outlet and other equipment in the refrigeration unit are made of two adjustable stainless steel flexible hoses for modular disassembly and transportation. Depending on the mine site conditions, one or two evaporators 14 can be connected in parallel. No water system is required, and they can be flexibly installed and moved in mining faces, chambers, etc., while achieving higher heat exchange efficiency.

[0029] This utility model's compact oil separation system for mining explosion-proof refrigeration units can use various Freon types, such as R22, R407C, R507A, or R134a, as refrigerants. During operation, the screw compressor 1 draws Freon into the evaporator 14 through its suction port. After compression, a mixture of high-temperature, high-pressure Freon superheated gas and high-temperature, high-pressure lubricating oil is formed. This mixture then sequentially enters the primary oil separator 3 and the secondary oil separator 4 through the discharge port of the screw compressor 1.

[0030] The high-temperature, high-pressure Freon gas separated from the secondary oil separator 4 enters the condenser 15, where it condenses into a high-temperature, high-pressure liquid. This high-temperature, high-pressure liquid is divided into three paths: The first path first undergoes subcooling treatment on the high-pressure side of the economizer 11, then passes through the throttling treatment of the evaporator supply pipe group 13, becoming a low-temperature, low-pressure Freon gas-liquid mixture, which then enters the evaporator 14, evaporates into low-temperature, low-pressure Freon gas, and finally returns to the suction port of the screw compressor 1, completing the refrigeration cycle. The second path is a small amount of high-temperature, high-pressure liquid, which first undergoes throttling treatment through the economizer supply pipe group 12, then enters the low-pressure side of the economizer 11, exchanges heat with the high-temperature, high-pressure liquid from the first path in the economizer 11, absorbs heat and evaporates, and then returns to the economizer injection port of the screw compressor 1. The third path first undergoes throttling treatment through the oil cooler supply pipe group 10, then enters the oil cooler 9, exchanges heat with the high-temperature, high-pressure lubricating oil from the primary oil separator 3, and finally returns to the suction port of the screw compressor 1, completing the refrigeration cycle.

[0031] Meanwhile, the high-temperature and high-pressure lubricating oil separated from the primary oil separator 3 passes sequentially through the coarse oil filter 6, oil cooler 9, oil pump 7, and fine oil filter 5, and exchanges heat with the low-temperature and low-pressure Freon gas-liquid mixture from the oil cooler supply pipe group 10 to cool it down. Finally, it returns to the shaft seals, bearings, and oil return ports of the screw compressor 1 to achieve lubrication of various components of the screw compressor 1.

[0032] In summary, by utilizing the technical solution of this utility model, the oil separator's footprint and lubricating oil filling volume can be significantly reduced while ensuring the oil separation effect of the screw compressor, thereby reducing the overall footprint and height of the mine explosion-proof refrigeration unit. It can accommodate transportation and installation in narrow underground tunnels, effectively avoiding equipment collisions during movement, improving the working efficiency of the refrigeration unit, and better meeting the needs of various small-scale mine operations.

[0033] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A mine-use explosion-proof refrigeration unit with a compact oil separation system, comprising a screw compressor (1), an economizer (11), a condenser (15), and an evaporator (14) connected by pipes and valves, characterized in that: It also includes a primary oil separator (3) and a secondary oil separator (4) connected in series. The exhaust port of the screw compressor (1) is connected to the mixed working fluid inlet of the primary oil separator (3). The refrigerant outlet of the primary oil separator (3) is connected to the mixed working fluid inlet of the secondary oil separator (4). The refrigerant outlet of the secondary oil separator (4) is connected to the refrigerant input end of the condenser (15). The oil outlet of the primary oil separator (3) is connected to the hot oil inlet of the oil cooler (9) through the coarse oil filter (6). The cold oil outlet of the oil cooler (9) is connected to the shaft seals, bearings and oil return ports of the screw compressor (1) through the oil pump (7) and the fine oil filter (5). The oil outlet of the secondary oil separator (4) is connected to the oil return port of the screw compressor (1). The refrigerant output of the condenser (15) is divided into three paths: the first path is connected to the high-pressure side inlet of the economizer (11), the high-pressure side outlet of the economizer (11) is connected to the refrigerant inlet of the evaporator (14) through the evaporator liquid supply pipe group (13), and the refrigerant outlet of the evaporator (14) is connected to the suction port of the screw compressor (1); the second path is connected to the low-pressure side inlet of the economizer (11) through the economizer liquid supply pipe group (12), and the low-pressure side outlet of the economizer (11) is connected to the economizer gas replenishment port of the screw compressor (1); the third path is connected to the refrigerant inlet of the oil cooler (9) through the oil cooler liquid supply pipe group (10), and the refrigerant outlet of the oil cooler (9) is connected to the suction port of the screw compressor (1).

2. The mine explosion-proof refrigeration unit with a compact layout of the oil separation system according to claim 1, characterized in that: The primary oil separator (3) and the secondary oil separator (4) are vertically arranged and placed side by side.

3. The mine explosion-proof refrigeration unit with a compact layout of the oil separation system according to claim 2, characterized in that: The main separation component of the inner cavity of the primary oil separator (3) is a wire mesh demister, and the main separation component of the inner cavity of the secondary oil separator (4) is a high-efficiency oil filter element.

4. The mine explosion-proof refrigeration unit with a compact layout of the oil separation system according to claim 3, characterized in that: The secondary oil separator (4) has two oil outlets: one is a natural flow oil outlet (4a), and the other is a high-efficiency filter oil outlet (4b). Both the natural flow oil outlet (4a) and the high-efficiency filter oil outlet (4b) are connected to the oil return port of the screw compressor (1) through the oil return pipeline.

5. The mine-use explosion-proof refrigeration unit with a compact layout of the oil separation system according to any one of claims 1 to 4, characterized in that: The oil cooler (9) and economizer (11) are plate-and-shell heat exchangers.

6. The mine-use explosion-proof refrigeration unit with a compact layout of the oil separation system according to any one of claims 1 to 4, characterized in that: The cold oil outlet of the oil cooler (9) is also directly connected to the oil return port of the screw compressor (1) through the oil return pipeline.

7. The mine explosion-proof refrigeration unit with a compact layout of the oil separation system according to any one of claims 1 to 4, characterized in that: The oil coarse filter (6) adopts a liquid path filtration structure, and the diameter of its inlet and outlet is larger than the diameter of the pipe connected to it.

8. The mine-use explosion-proof refrigeration unit with a compact layout of the oil separation system according to any one of claims 1 to 4, characterized in that: The evaporator liquid supply pipe group (13) and the oil cooler liquid supply pipe group (10) are composed of a shut-off valve, an electric regulating valve and a throttle valve connected in series, and the economizer liquid supply pipe group (12) is composed of an electric regulating valve and a throttle valve connected in series.

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