Pre-oiling process and oiling equipment for aluminum pipe of heat exchanger

Abstract

The invention relates to the technical field of aluminum pipe oil injection, and discloses a heat exchanger aluminum pipe pre-oil injection process and oil injection equipment. Oil injection connectors are evenly distributed on the top of a protection box, air blowing connectors fixed to the top of the protection box are arranged between every two adjacent oil injection connectors, and oil injection heads corresponding to the oil injection connectors are evenly distributed on the rear side wall of the protection box; blowing heads corresponding to the blowing connectors are evenly distributed on the rear side wall of the protection box, each set of oil injection connectors are connected with an oil injection tank through an oil injection pipe, each set of blowing connectors are connected with an air conveying pipe through an air blowing pipe, volatile oil carries lubricating oil to enter an aluminum pipe, only effective lubricating components are reserved after volatilization, a stable lubricating film is built before pipe expansion, and the lubricating effect is improved. The tooth-shaped change rate of the inner wall of the aluminum pipe is reduced from 31% to 11%, the risk that the expansion head adheres to aluminum is remarkably reduced, the tooth-shaped structure is protected, the traditional expansion pipe oiling procedure is omitted, and the machining efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil injection of aluminum pipes, and particularly relates to a heat exchanger aluminum pipe pre-oil injection process and an oil injection equipment. BACKGROUND

[0002] A heat exchanger is a device used to transfer heat from a hot fluid to a cold fluid to meet the specified process requirements, and is an industrial application of convection heat transfer and heat conduction. In the tube-fin heat exchanger used in household air conditioners and commercial air conditioners, aluminum pipes are used. The material of each part of the all-aluminum heat exchanger is aluminum. The aluminum pipe is a heat exchange pipe. After the heat exchange pipe is processed, it needs to be expanded, that is, the end of the aluminum pipe is expanded to facilitate the installation of the small U-shaped pipe.

[0003] In the expansion process of the tube-fin heat exchanger used in household air conditioners and commercial air conditioners, the expansion head is prone to sticking aluminum and other situations. The root cause is that the aluminum pipe is more sticky and more likely to stick to the expansion head. Sticking aluminum to the expansion head can cause scratches on the inner wall of the aluminum pipe and reduce the expansion efficiency.

[0004] In actual use, the prior art usually applies lubricating oil temporarily during expansion. The uneven application of oil to the inner wall of the aluminum pipe and the poor tooth-shaped protection effect are poor. Moreover, due to the long length of the aluminum pipe coil, the on-site oiling increases the process steps and reduces the degree of automation. In addition, the amount of oil applied is difficult to control, and excess oil can affect subsequent brazing operations.

[0005] Therefore, the present application provides a heat exchanger aluminum pipe pre-oil injection process and an oil injection equipment to solve the above problems. SUMMARY

[0006] The present application aims to provide a heat exchanger aluminum pipe pre-oil injection process and an oil injection equipment suitable for lubrication treatment before expansion of aluminum pipe coils (3000-5000 meters long) with an outer diameter of 4-20 mm to solve the problems raised in the background.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solution: a heat exchanger aluminum pipe oil injection equipment comprising a control cabinet, an oil injection tank fixed inside the control cabinet, a gas delivery pipe fixed on the top of the control cabinet, and the output end of the oil injection tank being connected to the gas delivery pipe through a high-pressure gas pipe, and an oil injection and blowing integrated machine being provided on the rear side of the control cabinet. The oil injection and blowing integrated machine comprises a support, a protection box fixed on the top of the support, oil injection joints uniformly distributed on the top of the protection box, blowing joints fixed on the top of the protection box and arranged between adjacent two groups of oil injection joints, oil injection heads uniformly distributed on the rear side wall of the protection box and corresponding to the oil injection joints, blowing heads uniformly distributed on the rear side wall of the protection box and corresponding to the blowing joints, each group of oil injection joints being connected to the oil injection tank through an oil injection pipe, and each group of blowing joints being connected to the gas delivery pipe through a blowing pipe.

[0008] Preferably, the top of the control cabinet is provided with a first maintenance window, the top of the protection box is uniformly provided with a second maintenance window, each group of oil injection joints is connected through oil delivery pipes and oil injection heads, each group of air blowing joints is connected through air pipes and air blowing heads, and valves are installed on each group of oil delivery pipes and air pipes.

[0009] Preferably, the control cabinet is provided with an air pump, the output end of the air pump is connected with the air delivery pipe, and the high-pressure air pipe is fixedly provided with an air inlet valve and a pressure gauge.

[0010] Preferably, a drying tank is arranged at the assembly position of the oil injection tank and the high-pressure air pipe, a pressure relief valve is arranged on the air delivery pipe, a safety valve is fixedly installed on the top of the oil injection tank, and the inside of the oil injection tank is filled with oil liquid composed of 90-98% of volatile oil and 2-10% of lubricating oil.

[0011] Preferably, the oil injection head is provided with a pipe clamping ring, and the oil injection head is provided with an oil injection nozzle at the end, the oil injection nozzle and the pipe clamping ring are in clearance fit, and the center line of the oil injection nozzle and the axis of the aluminum pipe form an included angle of 30-45°.

[0012] Preferably, an annular slot type nozzle is arranged at the outlet end face of the oil injection nozzle, abuts against the rear end of the pipe clamping ring, and a honeycomb flow stabilizer is coaxially installed at a position 3-5 mm away from the rear end of the annular slot type nozzle.

[0013] Preferably, a quantitative control module is arranged on each group of air blowing pipes, the quantitative control module comprises a proportional adjusting valve and an MFC main control unit, the control cabinet is provided with a PLC, and each group of proportional adjusting valves, MFC main control units and PLCs are connected.

[0014] Preferably, the air blowing head is a rotary blowing head, which comprises a rotary joint, a rotary rod, a servo motor and a hollow rod, the rotary joint comprises a shell, the rotary rod is rotatably arranged in the shell through a bearing, the servo motor is fixed on the shell, the output end of the servo motor is fixedly connected with the rotary rod, the hollow rod is threadedly locked on the other end of the rotary rod, and the other end of the hollow rod is provided with air blowing holes in the circumferential direction.

[0015] The application discloses a heat exchanger aluminum pipe pre-oil injection process, and steps of the pre-oil injection process are as follows. S1: lubricating oil is injected into the oil injection tank, the coil pipe and the oil injection head are butted, then the air pump is started, high-pressure gas is introduced into the top of the oil injection tank through the high-pressure air pipe, a continuous air pressure is formed in the oil injection tank, the lubricating oil is pressed out from the bottom oil outlet, and then the lubricating oil is injected into the coil pipe through the oil injection pipe, the oil injection joint and the oil injection head, so that multi-channel oil injection operation can be realized, multiple coil pipes can be processed in parallel, and the lubricating agent is pressed into the inner wall of the aluminum pipe by using high-pressure gas with a pressure of less than or equal to 6 MPa, and a continuous and uniform oil film is formed. S2: The high-pressure gas is then pumped into the air pipe through the air delivery pipe, and then into the coil through the air joint and the air head for a purge operation. The oil-filled coil is purged with dry high-pressure gas ≤6MPa. The residual oil volume is precisely controlled to 0.2%-3% by adjusting the purge gas pressure.

[0016] The technical effects and advantages of the present invention are as follows: The supporting equipment in the present invention adopts an integrated oil injection and blowing structure, and realizes simultaneous processing of multiple coils through multiple oil injection ports and blowing ports. The lubricating oil is carried into the aluminum tube by volatile oil, and only the effective lubricating components are retained after volatilization, avoiding the problem of excess or insufficient oil in the traditional oiling process. The high-pressure purge technology is used to ensure that the residual oil amount is within the range of 0.2%-3%, which not only reduces waste but also ensures sufficient lubrication during tube expansion. A stable lubricating film is established before tube expansion, so that the tooth profile change rate of the inner wall of the aluminum tube is reduced from 31% to 11%, significantly reducing the risk of aluminum sticking to the expansion head, protecting the tooth profile structure and improving heat exchange efficiency. At the same time, the traditional tube expansion oiling process is eliminated, and processing efficiency is improved. It is particularly suitable for the pretreatment of aluminum tube coils with an outer diameter of 4-20mm. The integrated oil injection and blowing structure can achieve efficient and continuous operation, and is suitable for large-scale production needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Fig. 1 This is a schematic diagram of the overall first-view structure of the present invention; Fig. 2 This is a schematic diagram of the overall second viewing angle structure of the present invention.

[0018] In the figure: 1. Control cabinet; 2. First inspection window; 3. Oil filling tank; 4. Air pipe; 5. Bracket; 6. Protective box; 7. Oil filling connector; 8. Air blowing connector; 9. Valve; 10. Oil filling head; 11. Air blowing head; 12. Oil filling pipe; 13. Air blowing pipe; 14. Second inspection window; 15. High-pressure air pipe. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] like Figs. 1-2 As shown, this embodiment discloses a heat exchanger aluminum tube oiling device, including a control cabinet 1, an oil filling tank 3 is fixed inside the control cabinet 1, an air supply pipe 4 is fixed on the top of the control cabinet 1, and the output end of the oil filling tank 3 is connected to the air supply pipe 4 through a high-pressure air pipe 15, and an oil filling and purge integrated machine is equipped on the rear side of the control cabinet 1, and the oil filling and purge operations of the coil are completed synchronously through the oil filling and purge integrated machine.

[0021] Please refer to Fig. 1 and Fig. 2 , the oil injection and blowing integrated machine includes a support 5, the top of the support 5 is fixed with a protective box 6, the top of the protective box 6 is uniformly distributed with an oil injection joint 7, and adjacent two groups of oil injection joints 7 are provided with a blowing joint 8 fixed on the top of the protective box 6, the rear wall of the protective box 6 is uniformly distributed with an oil injection head 10 corresponding to the oil injection joint 7, the rear wall of the protective box 6 is uniformly distributed with a blowing head 11 corresponding to the blowing joint 8, and each group of oil injection joints 7 is connected with an oil injection tank 3 through an oil injection pipe 12, and each group of blowing joints 8 is connected with a gas pipeline 4 through a blowing pipe 13.

[0022] The lubricating oil is injected into the oil injection tank 3, the coil pipe and the oil injection head 10 are docked, and then the air pump is started, so that the high-pressure gas is introduced into the top of the oil injection tank 3 through the high-pressure gas pipe 15, a continuous gas pressure is formed in the oil injection tank 3, the lubricating oil is pressed out from the bottom oil outlet, and then injected into the coil pipe through the oil injection pipe 12, the oil injection joint 7 and the oil injection head 10, so that multi-channel oil injection operation can be realized, and multiple coil pipes can be processed in parallel.

[0023] Then the high-pressure gas is dispersed into the blowing pipe 13 through the gas pipeline 4 by the air pump, and then input into the coil pipe through the blowing joint 8 and the blowing head 11, and the blowing operation is performed, and the dry high-pressure gas ≤6MPa is used to blow the coil pipe after oil injection.

[0024] The control cabinet 1 is provided with a first maintenance window 2 on the top, and the top of the protective box 6 is uniformly distributed with a second maintenance window 14, so that the internal structure can be maintained in real time, and each group of oil injection joints 7 is connected with an oil injection head 10 through an oil pipeline, and each group of blowing joints 8 is connected with a blowing head 11 through a gas pipe, and a valve 9 is installed on each group of oil pipelines and gas pipes, so that manual control of oil injection and blowing can be realized, which is convenient for manual control in emergency and improves the safety protection of the equipment.

[0025] The control cabinet 1 is internally provided with an air pump, and the output end of the air pump is connected with the air conveying pipe 4; the high-pressure air pipe 15 is fixedly provided with an air inlet valve and a pressure gauge; a drying tank is arranged at the assembly position of the oil injection tank 3 and the high-pressure air pipe 15; the air conveying pipe 4 is provided with a pressure relief valve; the oil injection tank 3 is fixedly provided with a safety valve at the top; the oil injection tank 3 is provided with an oil outlet valve at the bottom; in actual use, all the valves are closed, then the oil injection tank 3 is filled with lubricating oil, and a liquid level gauge is provided to detect the oil level in real time; then, the air inlet valve is slowly opened, the pressure gauge is observed, the air pressure in the oil injection tank 3 is adjusted to the required value, that is, the air pressure is less than or equal to 6 MPa, which is consistent with the subsequent purging pressure; the oil outlet valve at the bottom of the oil injection tank 3 is opened, and the lubricating oil is injected into the coil through the oil injection pipe 12, the oil injection connector 7 and the oil injection head 10 under the air pressure; after the oil injection operation is completed, the air inlet valve is closed, the exhaust valve at the top is opened to release the residual pressure, and finally the air source is disconnected and all the interfaces are blocked.

[0026] It should be noted that, during the high-pressure oil injection operation, the air pressure is increased in steps, that is, 2-3 MPa is used to achieve pre-wetting at the beginning, and 5-6 MPa is used for high-pressure spreading in the later stage, so as to avoid turbulence to cause oil film corrugation, and the oil injection speed is controlled at 1-5 m / s.

[0027] The oil liquid injected into the oil injection tank 3 is composed of 90-98% of volatile oil and 2-10% of lubricating oil. Specifically, the proportion of volatile oil is 90%-98%, which ensures rapid spreading; the proportion of lubricating oil is 2%-10%, which provides a film skeleton, and the two form a double-layer structure of “low-viscosity carrier + high-viscosity anchor” to avoid oil film shrinkage or rupture. In the embodiment, 95% of isoparaffin is used as the volatile oil, and 5% of PAO-40 is used as the lubricating oil. After the oil injection operation in the coil is completed, the 5% PAO-40 finally remaining in the coil plays a lubricating role, and the volatile oil will be directly volatilized.

[0028] It should be noted that the oil injection head 10 is provided with a pipe clamping ring, the inner tapered surface of the pipe clamping ring elastically clamps the outer wall of the aluminum pipe to achieve rapid positioning and centering, and the oil injection head 10 is provided with an oil injection nozzle at the end, the oil injection nozzle and the pipe clamping ring are gap-fitted, the center line of the oil injection nozzle and the axis of the aluminum pipe form an included angle of 30-45°, so that the subsequent spray generates a spiral airflow, and the lubricant is uniformly distributed in the circumferential direction.

[0029] An annular slot nozzle is arranged at the outlet end surface of the oil injection nozzle, closely abutting the rear end of the pipe clamping ring, the annular slot width is 0.1-0.3 mm, forming a 360° continuous fan-shaped spray, and the annular slot nozzle generates a fan-shaped spray rather than a point jet, a honeycomb flow stabilizer is coaxially arranged at a position 3-5 mm away from the rear end of the annular slot nozzle, which is used for rectifying and suppressing turbulence, and converts the high-pressure gas into laminar flow to avoid airflow impact damage to the oil film.

[0030] In actual use, the oil injection nozzle is pushed into the end of the coil pipe, the pipe clamping ring is automatically locked to the outer wall of the coil pipe under the action of the spring or quick release sleeve, coaxial positioning is completed, and high-pressure gas of ≤6 MPa enters through the lateral gas inlet of the oil injection nozzle, is first rectified into laminar flow by the honeycomb flow stabilizer, and the lubricant is sprayed out through the annular gap nozzle under the driving of the gas pressure, forms a rotating oil film on the inner wall of the coil pipe due to the 30-45° inclination angle, is uniformly distributed in the circumferential direction, maintains the set gas pressure for 1-3 s, ensures the continuity of the oil film, and finally the gas inlet is closed, the pipe clamping ring is unlocked, the end of the coil pipe is quickly withdrawn from the oil injection nozzle and is installed on the gas blowing head 11, and enters the subsequent high-pressure blowing process.

[0031] Each set of gas blowing pipe 13 is equipped with a quantitative control module, the quantitative control module includes a proportional regulating valve and an MFC master control unit, the control cabinet 1 is built-in PLC, each set of proportional regulating valve, MFC master control unit and PLC are connected, the MFC master control unit controls the gas flow in real time, the output value is fed back to the PLC, the PLC receives the feedback of the MFC and the sensor, runs the PID algorithm, dynamically adjusts the set point, the proportional regulating valve and the MFC master control unit are linked, used for fine tuning the pressure and flow, and reducing the fluctuation.

[0032] The gas blowing head 11 is a rotary blowing head, which includes a rotary joint, a rotary rod, a servo motor and a hollow rod, the rotary joint includes a shell, the rotary rod is rotatably assembled in the shell through a bearing, the servo motor is fixed on the shell, the output end of the servo motor is fixedly connected with the rotary rod, and the hollow rod is threadedly locked on the other end of the rotary rod, the other end of the hollow rod is provided with a gas blowing hole in the circumferential direction, and when the servo motor drives the rotary rod and the hollow rod to rotate, the hollow rod can rotate in the gas blowing process, the generated spiral airflow sweeps the whole length of the coil pipe, the residual oil amount is reduced to 0.2-3%, and the complete rotary blowing function of "gas blowing pipe 13 static gas supply + servo motor rotary driving + hollow rod end ring circumferential gas blowing" can be realized.

[0033] The embodiment discloses a heat exchanger aluminum pipe pre-oil injection process, and steps of the pre-oil injection process are as follows. S1: lubricating oil is injected into the oil injection tank 3, the coil pipe and the oil injection head 10 are docked, then the gas pump is started, high-pressure gas is introduced into the top of the oil injection tank 3 through the high-pressure gas pipe 15, a continuous gas pressure is formed in the oil injection tank 3, the lubricating oil is pressed out from the bottom oil outlet, then the lubricating oil is injected into the coil pipe through the oil injection pipe 12, the oil injection joint 7 and the oil injection head 10, multi-channel oil injection operation can be realized, multiple coil pipes can be processed in parallel, high-pressure gas with pressure ≤6 MPa is used to press the lubricant into the inner wall of the aluminum pipe, a continuous and uniform oil film is formed, multiple coil pipes are processed synchronously through multiple oil injection ports and gas blowing ports, the lubricating oil is carried into the aluminum pipe by volatile oil, only effective lubricating components are left after volatilization, and the problems of excessive or insufficient oil in the traditional oil coating process are avoided; S2: Then the high-pressure gas is dispersed into the blowing pipe 13 through the gas pipe 4 by the air pump, and then is input into the coil through the blowing joint 8 and the blowing head 11, and the purging operation is performed. The dry high-pressure gas with a pressure of ≤6 MPa is used to purge the oil-filled coil, the residual oil amount is accurately controlled to be 0.2%-3% by adjusting the purging gas pressure, the high-pressure purging technology is used to ensure that the residual oil amount is within the range of 0.2%-3%, the waste is reduced, and the lubrication is sufficient when the tube is expanded, a stable lubricating film is established before the tube is expanded, the tooth shape change rate of the inner wall of the aluminum tube is reduced from 31% to 11%, the risk of aluminum sticking to the expansion head is significantly reduced, the tooth shape structure is protected and the heat exchange efficiency is improved, the traditional oiling and blowing process is omitted, the processing efficiency is improved, and the integrated oiling and blowing structure can realize efficient continuous operation and is suitable for large-scale production requirements.

[0034] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the foregoing embodiments of the present application are described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement, within the spirit and principles of the present application, any modification, equivalent replacement, improvement, etc., should be included in the protection scope of the present application.

Claims

1. A heat exchanger aluminum tube oiling device, characterized by: It comprises a control cabinet (1), wherein an oil filling tank (3) is fixed inside the control cabinet (1), an air supply pipe (4) is fixed on the top of the control cabinet (1), and the output end of the oil filling tank (3) is connected to the air supply pipe (4) through a high-pressure air pipe (15), and an oil filling and purge integrated machine is provided on the rear side of the control cabinet (1); The oil filling and blowing integrated machine comprises a bracket (5), a protective box (6) is fixed on the top of the bracket (5), oil filling joints (7) are evenly distributed on the top of the protective box (6), and an air blowing joint (8) fixed on the top of the protective box (6) is provided between two adjacent groups of oil filling joints (7), oil filling heads (10) corresponding to the oil filling joints (7) are evenly distributed on the rear side wall of the protective box (6), and air blowing heads (11) corresponding to the air blowing joints (8) are evenly distributed on the rear side wall of the protective box (6), and each group of oil filling joints (7) is connected to the oil filling tank (3) through an oil filling pipe (12), and each group of air blowing joints (8) is connected to the air supply pipe (4) through an air blowing pipe (13).

2. The heat exchanger aluminum tube oiling equipment according to claim 1, characterized in that: The control cabinet (1) is provided with a first inspection window (2) on the top, and the protection box (6) is provided with a second inspection window (14) on the top. Each set of oil filling joints (7) is connected to the oil filling head (10) through an oil delivery pipe, and each set of air blowing joints (8) is connected to the air blowing head (11) through an air pipe, and valves (9) are installed on each set of oil delivery pipes and air pipes.

3. The heat exchanger aluminum tube oiling equipment according to claim 1, characterized in that: The control cabinet (1) has an internal air pump, and the output end of the air pump is connected to the air delivery pipe (4). An air inlet valve and a pressure gauge are fixedly mounted on the high-pressure air pipe (15).

4. The heat exchanger aluminum tube oiling equipment according to claim 3, characterized in that: A drying tank is installed at the assembly point of the oil filling tank (3) and the high-pressure gas pipe (15), a pressure relief valve is installed on the gas transmission pipe (4), a safety valve is fixedly installed on the top of the oil filling tank (3), and an oil liquid composed of 90-98% volatile oil and 2-10% lubricating oil is injected into the oil filling tank (3).

5. The heat exchanger aluminum tube oiling equipment according to claim 1, characterized in that: The oiling head (10) is equipped with a pipe clamping ring, and an oiling nozzle is provided at the end of the oiling head (10). The oiling nozzle and the pipe clamping ring are clearance-matched, and the center line of the oiling nozzle forms an angle of 30-45 degrees with the axis of the aluminum tube.

6. The heat exchanger aluminum tube oiling equipment according to claim 5, characterized in that: An annular gap nozzle is provided at the outlet end face of the oiling nozzle, close to the rear end of the pipe clamping ring, and a honeycomb flow stabilizer is coaxially installed 3-5mm away from the rear end of the annular gap nozzle.

7. The heat exchanger aluminum tube oiling equipment according to claim 1, characterized in that: Each set of air blowing pipes (13) is equipped with a quantitative control module, which includes a proportional control valve and an MFC main control unit. The control cabinet (1) has a built-in PLC, and each set of proportional control valves, the MFC main control unit and the PLC are connected.

8. The heat exchanger aluminum tube oiling equipment according to claim 7, characterized in that: The blowing head (11) is a rotary blowing head, which includes a rotary joint, a rotating rod, a servo motor and a hollow rod. The rotary joint includes a shell. The rotating rod is rotatably assembled inside the shell through a bearing. The servo motor is fixed to the shell. The output end of the servo motor is fixedly connected to the rotating rod. The hollow rod is installed at the other end of the rotating rod through threaded locking. The other end of the hollow rod is circumferentially provided with a blowing hole.

9. A heat exchanger aluminum tube pre-oiling process, implemented using the heat exchanger aluminum tube oiling equipment according to claim 1, characterized in that: The steps of the pre-oiling process are: S1: inject lubricating oil into the oil filling tank (3), and simultaneously connect the coil and the oil filling head (10), and then start the air pump so that high-pressure gas is passed through the high-pressure gas pipe (15) to the top of the oil filling tank (3), forming a continuous air pressure in the oil filling tank (3), pressing the lubricating oil out from the bottom oil outlet, and then injecting the lubricating oil into the coil through the oil filling pipe (12), the oil filling joint (7) and the oil filling head (10), so as to realize multi-channel oil filling operation and realize multi-coil parallel processing, and use high-pressure gas with a pressure of ≤6MPa to press the lubricant into the inner wall of the aluminum tube to form a continuous and uniform oil film; S2: The high-pressure gas is then dispersedly input into the air blowing pipe (13) through the air delivery pipe (4) by the air pump, and then input into the coil through the air blowing joint (8) and the air blowing head (11) to perform a purge operation. The coil that has been oiled is purged with dry high-pressure gas of ≤6MPa. By adjusting the purge gas pressure, the residual oil amount is accurately controlled to 0.2%-3%.

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