Heat exchange device for waste heat recovery of screw air compressor

Abstract

A heat exchange device for waste heat recovery of a screw air compressor comprises a U-shaped coil pipe, a spiral fin is arranged on a straight pipe section of the U-shaped coil pipe, a sleeve is arranged outside the spiral fin, and the sectional area of the sleeve is larger than that of the U-shaped coil pipe. The two ends of each sleeve are closed, connecting pipes are arranged on the pipe walls of the closed ends, and the sleeves are sequentially connected through the connecting pipes. A cold medium is introduced into the sleeve, and a hot medium from the screw air compressor is introduced into the U-shaped coil pipe. The heat exchange device adopts a double-layer tubular heat exchange structure, a hot medium is introduced into the tube, a cold medium is introduced outside the tube, and heat is exchanged through the tube wall and the spiral fins. According to the heat exchange device, waste heat generated by the screw air compressor is recycled, the water supply requirement of a bathhouse is met, and the screw air compressor is effectively cooled. The heat exchange device has the advantages of being small in size, compact in structure, high in heat exchange efficiency and reasonable in heat exchange matching.

Description

Technical Field

[0001] The utility model relates to the field of mining, in particular to a heat exchange device for recovering waste heat from a screw air compressor. Background Art

[0002] The screw air compressor unit is one of the main energy-consuming equipment of mining enterprises, and the total installed power is usually above 1000KW. According to the data, during the operation of the screw air compressor, only 15% of the energy is converted into gas energy, and the remaining energy is almost converted into heat energy, and most of this heat energy is stored in the lubricating oil, and the oil temperature of the lubricating oil can reach 80-100℃. The lubricating oil has two functions: one is to lubricate the screw to reduce wear; the other is to cool the screw and take away heat. The existing screw air compressor is equipped with a circulation pump, a heat pipe and a fan. After the lubricating oil is pumped into the heat pipe, it is cooled by the fan, resulting in a large waste of heat energy.

[0003] In order to recycle the waste heat generated by the screw air compressor, our mine plans to use plate heat exchangers to provide hot water for the employee bathhouse, but it is found that the heat exchange efficiency of the plate heat exchanger is only 60-70%. If the heat required for heating is achieved, the volume of the plate heat exchanger must be increased. However, the space in the screw air compressor cabinet is limited, and a plate heat exchanger with a large volume cannot be installed. In particular, the diameter of the hot medium flow pipe of the existing plate heat exchanger is the same as the diameter of the cold medium flow pipe. For this application, the lubricating oil is the hot medium and the bathing water is the cold medium. The flow rate of the hot medium is much smaller than the flow rate of the cold medium. This is a mismatch in heat exchange, which will cause a further reduction in heat exchange efficiency. Therefore, a heat exchange device that can be installed in a cabinet, has heat exchange matching and high efficiency is needed. Utility Model Content

[0004] In order to overcome the shortcomings of the background technology, the utility model discloses a heat exchange device for recovering waste heat from a screw air compressor, which adopts the following technical solutions:

[0005] A heat exchange device for recovering waste heat from a screw air compressor comprises a U-shaped coil, wherein a spiral fin is arranged on the straight tube section of the U-shaped coil, and a sleeve is arranged outside the spiral fin, wherein the cross-sectional area of ​​the sleeve is larger than the cross-sectional area of ​​the U-shaped coil; both ends of the sleeve are closed, and a connecting pipe is arranged on the tube wall of the closed end, and each sleeve is connected in sequence through the connecting pipe; a cold medium is introduced into the sleeve, and a hot medium from the screw air compressor is introduced into the U-shaped coil.

[0006] To further improve the technical solution, the spiral fins are in multiple groups and are evenly distributed on the outer tube surface of the straight tube section of the U-shaped coil.

[0007] To further improve the technical solution, the sleeve is formed by two semicircular groove-shaped parts that are snap-fitted together.

[0008] To further improve the technical solution, a heat-insulating sleeve is provided on the curved section of the U-shaped coil.

[0009] To further improve the technical solution, the connecting pipe is detachably connected via a flange.

[0010] To further improve the technical solution, the flow direction of the cold medium is opposite to the flow direction of the hot medium.

[0011] To further improve the technical solution, the cold medium is domestic water or industrial water.

[0012] Due to the adoption of the above technical solution, compared with the background technology, the utility model has the following beneficial effects:

[0013] This heat exchange device adopts a double-layer tube heat exchange structure, with hot medium passing through the tube and cold medium passing through the tube, and heat is exchanged through the tube wall and spiral fins. Compared with the plate heat exchanger, this heat exchange device is small in size and compact in structure, and can be installed in the cabinet of the screw air compressor; this heat exchange device has high heat exchange efficiency, and the heat exchange efficiency is greater than 90%, which meets the needs of bathhouse water supply; because the cross-sectional area of ​​the casing is larger than the cross-sectional area of ​​the U-shaped coil, the flow rate of the lubricating oil in the U-shaped coil is small, the cooling process is long, and the temperature drop is large, so that the screw is effectively cooled; although the flow rate of cold water in the casing is large, the spiral fins increase the heat exchange area, and the water temperature of the bath water is increased while ensuring sufficient water consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the structure of the heat exchange structure.

[0015] Figure 2 for Figure 1 A partial enlarged view of .

[0016] In the figure: 1. U-shaped coil; 2. spiral fin; 3. casing; 4. connecting pipe; 5. connecting flange; 6. insulation sleeve. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that in the description of the present invention, the terms "front", "rear", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0018] A heat exchange device for recovering waste heat from a screw air compressor is installed in a cabinet of the screw air compressor. The waste heat generated by the screw air compressor is used to provide hot water for a staff bathhouse, while lowering the temperature of the lubricating oil to cool the screw in the screw air compressor.

[0019] like Figure 1-2 As shown, the heat exchange device includes a U-shaped coil 1 composed of a straight tube section and a curved tube section. The U-shaped coil 1 is placed vertically, and a spiral fin 2 is provided on the straight tube section of the U-shaped coil 1. The spiral fin 2 is divided into three groups and evenly distributed on the outer tube surface of the straight tube section of the U-shaped coil 1. The more groups of spiral fins 2 there are, the larger the surface area is, and the better the heat exchange effect is. A sleeve 3 is provided on the outside of the spiral fin 2, and both ends of the sleeve 3 are closed, so that a spiral flow channel is formed between the sleeve 3 and the U-shaped coil 1. A connecting pipe 4 is provided on the tube wall at the closed end, and each sleeve 3 is connected in sequence through the connecting pipe 4.

[0020] The above connection structure is adopted because due to process limitations, the spiral fin 2 cannot be welded to the curved section of the U-shaped coil 1, nor can the curved sleeve 3 be welded around the spiral fin 2. Therefore, the sleeve 3 can be formed by two semicircular groove-shaped parts that are buckled and connected. This can reduce the process difficulty and facilitate the production and assembly of the heat exchange device.

[0021] For ease of assembly and maintenance, each connecting pipe 4 is connected by connecting flange 5 and bolts. In order to prevent the temperature loss of lubricating oil in the curved section of the U-shaped coil 1, an insulation sleeve 6 is provided in the curved section of the U-shaped coil 1, and the insulation sleeve 6 is also connected in a split manner.

[0022] In this embodiment, the cold medium introduced into the sleeve 3 is cold water, and the lubricating oil from the screw air compressor is introduced into the U-shaped coil 1, and the oil temperature of the lubricating oil is 80-100°C. The flow direction of the cold water is opposite to that of the lubricating oil, and the cold water is used to cool the lubricating oil. Since the heat exchange device adopts a double-layer tube heat exchange structure, it is small in size and compact in structure, and can be installed in the cabinet of the screw air compressor.

[0023] The amount of lubricating oil in the screw air compressor is limited, and the circulation volume of lubricating oil cannot be very large, while the amount of water used for bathing is very large, which results in a mismatch in the flow rate of the cold and hot heat exchange media. This mismatch will cause two situations: one is that the amount of water used for bathing is very small, but the water temperature is very high; the other is that the amount of water used for bathing is very large, but the water temperature is not enough. Since the cross-sectional area of ​​the sleeve 3 is larger than the cross-sectional area of ​​the U-shaped coil 1, the flow rate of the lubricating oil in the U-shaped coil 1 is small, the cooling process is long, and the temperature drop is large, which can effectively cool the screw. Although the flow rate of cold water in the sleeve 3 is large, the spiral fins 2 increase the heat exchange area, and the water temperature of the bath water is increased while ensuring sufficient water consumption. Since the flow direction of cold water is opposite to that of lubricating oil, the temperature of cold water flowing out of the sleeve 3 can be made higher than the temperature of lubricating oil flowing out of the U-shaped coil 1. It has been verified that after heat exchange, the water temperature increases from 20℃ to 50-65℃, ensuring the water needs of the bathhouse; the oil temperature of the lubricating oil drops from 80-100℃ to 40-50℃, achieving effective cooling of the screw.

[0024] It is worth noting that the cold medium can also be other domestic water or industrial water.

[0025] The parts not described in detail in the present invention are prior art. Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A heat exchange device for recovering waste heat from a screw air compressor, characterized in that: It comprises a U-shaped coil, wherein a spiral fin is arranged on the straight tube section of the U-shaped coil, a sleeve is arranged outside the spiral fin, and the cross-sectional area of ​​the sleeve is larger than the cross-sectional area of ​​the U-shaped coil; both ends of the sleeve are closed, a connecting pipe is arranged on the tube wall of the closed end, and each sleeve is connected in sequence through the connecting pipe; a cold medium is passed into the sleeve, and a hot medium from a screw air compressor is passed into the U-shaped coil.

2. A heat exchange device for recovering waste heat from a screw air compressor as claimed in claim 1, characterized in that: The spiral fins are in multiple groups and are evenly distributed on the outer tube surface of the straight tube section of the U-shaped coil.

3. The heat exchange device for recovering waste heat from a screw air compressor according to claim 1, characterized in that: The sleeve is formed by two semicircular groove-shaped parts being buckled and connected.

4. The heat exchange device for recovering waste heat from a screw air compressor according to claim 1, characterized in that: A heat-insulating sleeve is provided on the curved section of the U-shaped coil.

5. The heat exchange device for recovering waste heat from a screw air compressor according to claim 1, characterized in that: The connecting pipe is detachably connected via a flange.

6. A heat exchange device for recovering waste heat from a screw air compressor as claimed in claim 1, characterized in that: The flow direction of the cold medium is opposite to that of the hot medium.

7. The heat exchange device for recovering waste heat from a screw air compressor according to claim 1, characterized in that: The cold medium is domestic water or industrial water.

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