A pipe internal membrane coating apparatus and method

Abstract

The application provides a pipeline inner film coating device and method, and belongs to the technical field of heat exchange pipes. The device comprises a bottom frame, a cylinder jacking device arranged in the bottom frame, a limiting support, one end of which is rotatably connected to one end of the bottom frame, and the other end is slidably connected to the cylinder jacking device, a discharge port clamp arranged at one end of the limiting support and the bottom frame, and fixed on the limiting support through a motor driving device, and a feeding port clamp movably arranged at the other end of the limiting support, and further connected with a feeding device. The application adopts an inclined rotary self-gravity coating, has obvious advantages for the inner wall coating of small-diameter and long pipes, the calculation of the required amount of slurry does not need to be very accurate, and the excess slurry can be discharged with the pipeline; and the film layer obtained by the coating is uniformly distributed, and the slurry layering phenomenon caused by high-speed centrifugation can be effectively avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of heat exchange pipes, and particularly relates to a pipeline inner film coating device and method. BACKGROUND

[0002] Sintered high-flux heat exchange pipes are widely used in the field of coal chemical industry, and the heat transfer efficiency of the porous surface boiling heat transfer strengthening mechanism can be several times higher than that of ordinary light pipes. The porous layer preparation technology of the surface is relatively mature. Spraying, electrodeposition, mechanical processing and other methods are various.

[0003] Chinese patent publication CN104962903A discloses a manufacturing method and device of a surface porous heat exchange pipe, which adopts the combination of coating and induction coil to prepare the porous layer of the outer surface. Chinese patent publication CN101367127A discloses a centrifugal coating vacuum sintering processing method of a metal porous surface in a heat exchange pipe, which uniformly coats the coating on the inner surface of the pipe by using the centrifugal coating process, and heats to a specific temperature under vacuum conditions to form a metallurgical bond on the inner surface of the metal pipe and form a metal porous surface in the pipe; the method has high requirements for the calculation accuracy of the slurry and the equipment speed. Chinese patent publication CN1730204A discloses a processing method of a metal porous surface in a heat exchange pipe, which coats the inner surface of the pipeline by using a mechanical coating method, and uses a probe coating method. This method is inevitably limited by the pipe diameter and the pipe length.

[0004] Therefore, there is an urgent need to develop a pipeline inner film coating device which is not affected by the pipe diameter and the pipe length, and has low requirements for the calculation accuracy of the slurry amount. SUMMARY

[0005] The purpose of the present application is to solve the problems existing in the prior art, and to provide a pipeline inner film coating device and method, which has obvious advantages in coating the inner wall of a small-diameter and long-pipeline by using an inclined rotary self-gravity coating, does not require high accuracy in calculating the amount of slurry, and can discharge the excess slurry along with the pipeline; and can effectively avoid the stratification of the slurry caused by high-speed centrifugation.

[0006] The present application is realized by the following technical solutions:

[0007] In a first aspect, the present application provides a pipeline inner film coating device, comprising:

[0008] A bottom frame is provided with a cylinder jacking device;

[0009] A limiting support is rotatably connected to one end of the bottom frame at the bottom surface, and is slidably connected to the cylinder jacking device at the bottom surface near the end position;

[0010] The discharge port clamp is arranged at one end of the limiting support and the bottom frame rotationally connected, and is fixed on the limiting support through the motor driving device.

[0011] The feeding port clamp is movably arranged at the other end of the limiting support, and the feeding port clamp is further connected with a feeding device.

[0012] The further improvement of the present application is that:

[0013] One end of the bottom surface of the limiting support is rotationally connected with one end of the bottom frame through three rotating shafts.

[0014] The bottom surface of the other end of the limiting support close to the end position is slidingly connected with the cylinder jacking device, specifically, a limiting groove is arranged on the bottom surface of the limiting support along the length direction, and the cylinder body of the cylinder jacking device is arranged in the limiting groove, so that the cylinder body can slide in the limiting groove during the ascending or descending process of the cylinder jacking device, and then the limiting support is jacked up by a certain angle.

[0015] The further improvement of the present application is that:

[0016] The discharge port clamp comprises a discharge port clamp body, the discharge port clamp body is provided with a central through hole along the axis direction, and one end of the discharge port clamp body is provided with an annular groove;

[0017] The central through hole and the annular groove are coaxially arranged;

[0018] A rubber sealing ring is arranged in the annular groove;

[0019] One end of the outer wall of the discharge port clamp body close to the annular groove is provided with a step, and the outer diameter of the discharge port clamp body gradually decreases from the step to the other end, which is used for fixedly connecting with the motor driving device.

[0020] The further improvement of the present application is that:

[0021] The motor driving device is arranged at one end of the limiting support and the bottom frame rotationally connected, and is welded on the limiting support;

[0022] One end of the discharge port clamp with small outer diameter is clamped into the hollow roller shaft of the motor driving device, the other end of the hollow roller shaft of the motor driving device is fixedly provided with a surplus material discharge pipe through a wire port, and the surplus material discharge pipe is provided with a discharge through hole along the axis direction.

[0023] The further improvement of the present application is that:

[0024] The feeding port clamp comprises a feeding port clamp body, one end of the feeding port clamp body is provided with an annular clamping groove, and a rubber sealing ring is arranged in the annular clamping groove;

[0025] The feeding port clamp body is provided with a center through hole in the axial direction, and the diameter of the center through hole gradually increases from one end of the annular clamping groove to the other end.

[0026] The feeding port clamp body is provided with a step on the outer wall, the outer diameter of the feeding port clamp body from the annular clamping groove to one side of the step is larger than the outer diameter from the step to the other end, and the end of the feeding port clamp body with the small outer diameter is connected with the feeding device.

[0027] Further improvement of the present application is that:

[0028] The feeding device comprises a horizontal feeding pipe, a feeding hopper is connected to the side wall of the horizontal feeding pipe, and a feeding spring is arranged in the horizontal feeding pipe.

[0029] One end of the horizontal feeding pipe is open, and the other end is closed, wherein a roller shaft is welded at the pipe opening of the open end of the horizontal feeding pipe, and a fixing seat is welded at the closed end of the horizontal feeding pipe, and the fixing seat is fixed on the limiting support through bolts.

[0030] Further improvement of the present application is that:

[0031] The pipe opening of the horizontal feeding pipe is welded with the outer ring of the roller shaft.

[0032] The feeding spring is welded and connected with one side of the inner ring of the roller shaft, the other side of the inner ring of the roller shaft is welded with a connecting pipe, and the other end of the connecting pipe is connected with the feeding port clamp.

[0033] In the second aspect of the present application, a pipeline inner film coating method is provided, which is carried out by using the pipeline inner film coating equipment, and specifically comprises the following steps:

[0034] First, fix the pipeline between the feeding port clamp and the discharging port clamp, start the motor driving device to adjust the rotating speed to 0-80r / min, preferably 40r / min-60r / min, adjust the cylinder jacking device at the same time to make the pipeline form an angle of 0°-45° with the horizontal plane, preferably 15°-30°, then pour the slurry into the feeding device through the feeding hopper, and realize the coating of the pipeline inner film.

[0035] Further improvement of the present application is that:

[0036] The slurry comprises, by mass percentage: 60wt.%-70wt.% metal powder, 5wt.%-10wt.% binder, 20wt.%-25wt.% organic solvent, and 5wt.%-10wt.% pore-forming agent.

[0037] Further improvements of the present application are:

[0038] The metal powder comprises 316L stainless steel powder or titanium powder or a mixed powder of 316L stainless steel powder and low-melting-point brazing powder, or a mixed powder of titanium powder and low-melting-point brazing powder, wherein the mass ratio of 316L stainless steel powder to low-melting-point brazing powder in the mixed powder of 316L stainless steel powder and low-melting-point brazing powder is 3-4:1, and the mass ratio of titanium powder to low-melting-point brazing powder in the mixed powder of titanium powder and low-melting-point brazing powder is 3-4:1;

[0039] The binder comprises polyvinylpyrrolidone or a mixture of polyvinylpyrrolidone and polyethylene glycol, wherein the mass ratio of polyvinylpyrrolidone to polyethylene glycol in the mixture is 9:1;

[0040] The organic solvent is anhydrous ethanol;

[0041] The pore-forming agent is PMMA microspheres.

[0042] Compared with the prior art, the present application has the following advantages:

[0043] The present application provides a pipeline inner film coating device, which has obvious advantages in coating the inner wall of a pipeline with a small diameter and a long length by adopting an inclined type rotation self-gravity coating. The calculation of the required amount of slurry does not need to be very accurate, and the excess slurry can be discharged with the pipeline. The film layer obtained by coating is uniformly distributed, which can effectively avoid the stratification of the slurry caused by high-speed centrifugation. In summary, the inner wall coating device that can be applied to heat exchange pipes has certain advantages compared with the existing inner film coating device.

[0044] The present application provides a pipeline inner film coating method, which fills an excessive amount of slurry into a feeding device. During the inner film coating process, by controlling the proportioning of the slurry, the inclination angle of the pipeline, and the rotating speed of the motor driving device, a film layer with uniform distribution and a certain thickness, about 100-150μm, can be obtained. As can be seen from the surface and cross-sectional microstructure of the inner film layer, the surface presents a clear porous structure, and the powder particles are well combined. The pores are also uniformly distributed as can be seen from the cross section. There are many through-hole structures from the surface of the base pipe to the surface of the film layer. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 is a structural schematic view of a pipeline inner film coating device provided by the present application;

[0046] Figure 2 is a working state schematic diagram of a pipeline inner film coating equipment provided by the present application;

[0047] Figure 3 is a cross-sectional schematic diagram of a discharge port clamp;

[0048] Figure 4 is a cross-sectional schematic diagram of a feeding port clamp;

[0049] Figure 5 is a connecting sectional view of the feeding port clamp and a feeding device;

[0050] Figure 6 is a microstructure diagram of the pipeline inner film prepared by the process.

[0051] In the figure, 1 is a bottom frame, 2 is a cylinder jacking device, 3 is a limiting support, 4 is a discharge port clamp, 5 is a feeding port clamp, 6 is a feeding device, 6-1 is a horizontal feeding pipe, 6-2 is a feeding hopper, 6-3 is a feeding spring, 7 is a motor driving device, 8 is a surplus material discharge pipe, 9 is a roller, 10 is a connecting pipe, 11 is a fixing seat, 12 is an induction coil, 13 is a sliding rail, and 14 is a fine adjustment assembly. DETAILED DESCRIPTION

[0052] The present application will be further described in detail below with reference to the accompanying drawings:

[0053] The present application provides a pipeline inner film coating equipment, which is suitable for the inner film coating of a composite film tube with a length of 1500 mm, a pipe diameter of 10 mm to 50 mm, and a film layer thickness of about 200 μm. The film tube is mainly applied to boiling heat transfer and heat exchange materials.

[0054] As shown in Figure 1 , the present application provides a pipeline inner film coating equipment, which comprises:

[0055] A bottom frame 1 is provided with a cylinder jacking device 2.

[0056] A limiting support 3 is rotatably connected to one end of the bottom frame 1 and slidably connected to the cylinder jacking device 2 at the bottom surface of the other end close to the end position.

[0057] A discharge port clamp 4 is arranged at the end of the limiting support 3 rotatably connected to the bottom frame 1 and fixed on the limiting support 3 by a motor driving device 7.

[0058] A feeding port clamp 5 is movably arranged at the other end of the limiting support 3, and a feeding device 6 is further connected to the feeding port clamp 5.

[0059] As shown in Figure 2As shown, when the inner film of the pipe is coated, the pipe is first fixed between the discharge port clamp 4 and the feed port clamp 5, and the limiting support 3 is lifted to a certain angle by adjusting the lifting of the air cylinder lifting device 2, and the size of the angle is adjustable between 0° and 45°, so that the slurry poured through the feeding device 6 can flow downward by its own gravity, and at the same time, the discharge port clamp 4, the pipe and the feed port clamp 5 are uniformly rotated under the driving of the motor driving device 7, realizing the spiral uniform coating of the inner film of the pipe.

[0060] As a preferred embodiment of the present application, one end of the limiting support 3 is rotatably connected to one end of the bottom frame 1 through three rotating shafts, and the air cylinder lifting device 2 is a compression cylinder. The bottom surface of the other end of the limiting support 3 near the end position is slidably connected to the air cylinder lifting device 2. Specifically, a limiting groove is arranged on the bottom surface of the limiting support 3 along the length direction, and the cylinder body of the compression cylinder is arranged in the limiting groove, so that the cylinder body can slide in the limiting groove during the lifting or lowering of the compression cylinder, and then the limiting support 3 is lifted to a certain angle, and the angle is controlled within 0° to 45°.

[0061] As a preferred embodiment of the present application, as shown, Figure 3 The discharge port clamp 4 includes a discharge port clamp body, and the discharge port clamp body is provided with a central through hole in the axial direction, which is a flow guide channel for the slurry. One end of the discharge port clamp body is provided with an annular groove, which is formed by extending inward from the end of the discharge port clamp body. The annular groove is a bayonet for fixing the pipe or pipe material. The central through hole and the annular groove are coaxially arranged to prevent deviation or vibration during rotation and affect the coating quality of the inner film of the pipe. A rubber sealing ring is arranged in the annular groove. Because the rotation of the pipe material is driven by the friction provided by the clamp during the operation of the machine, the rubber sealing ring can provide greater friction. In addition, the slurry contains alcohol and other liquids, and the rubber sealing ring can play a sealing role.

[0062] One end of the discharge port clamp body is tapered and clamped in the tapered hole of the hollow roller shaft of the motor driving device 7, so as to realize the rotation of the discharge port clamp 4 driven by the motor driving device 7. Specifically, a step is arranged on the outer wall of the discharge port clamp body near one end of the annular groove, and the outer diameter of the discharge port clamp body gradually decreases from the step to the other end, which is used for fixed connection with the motor driving device 7 and clamped in the tapered hole of the hollow roller shaft of the motor driving device 7. The two are tightly matched, and tools are needed to knock them out when disassembling.

[0063] As a preferred embodiment of the present application, the motor driving device 7 is arranged at one end of the limiting support 3 and the bottom frame 1, and is welded on the limiting support 3. The small end of the discharge port clamp 4 is clamped into the hollow roller of the motor driving device 7, which is convenient for disassembly. The other end of the hollow roller of the motor driving device 7 is fixed with the excess material discharge pipe 8 through the screw port. The excess material discharge pipe 8 is provided with a discharge hole along the axis direction. The excess slurry in the pipeline coating process will be discharged through the central hole of the discharge port clamp body, the hole of the hollow roller of the motor driving device 7 and the discharge hole of the excess material discharge pipe 8 in turn.

[0064] The central axes of the discharge hole, the hole of the hollow roller and the central hole of the discharge port clamp are located on the same straight line.

[0065] When the motor driving device 7 drives the rotation of the discharge port clamp 4, the excess material discharge pipe 8 will also rotate together, and the excess slurry will flow out slowly with the rotation.

[0066] The motor driving device 7 adopts a stepless speed control digital display motor, which is preferably a 1.5KW three-phase asynchronous motor. The rotating speed can be adjusted and controlled between 0-80r / min, which can drive the uniform rotation of the discharge port clamp 4, the pipe and the feeding port clamp 5.

[0067] As a preferred embodiment of the present application, as shown in Figure 4 The feeding port clamp 5 includes a feeding port clamp body. One end of the feeding port clamp body is provided with an annular clamping groove, which is formed by extending inward from the end of the feeding port clamp body. The annular clamping groove is a clamping port for fixing the pipeline or pipe. A rubber sealing ring is arranged in the annular clamping groove. The rubber sealing ring can provide a large friction force for the pipe. In addition, the slurry contains alcohol and other liquids, and the rubber sealing ring can play a sealing role.

[0068] A step is arranged on the outer wall of the feeding port clamp body. The outer diameter of the feeding port clamp body from the annular clamping groove to one side of the step is larger than the outer diameter from the step to the other end. The end of the feeding port clamp body with small outer diameter is connected with the feeding device.

[0069] A central hole is arranged on the feeding port clamp body along the axis direction. The diameter of the central hole gradually increases from one end of the annular clamping groove to the other end. The central hole and the annular clamping groove are coaxial to prevent deviation or vibration during rotation and affect the coating quality of the pipeline inner film.

[0070] As a preferred embodiment of the present application, the feeding device 6 includes a horizontal feeding pipe 6-1. The side wall of the horizontal feeding pipe 6-1 is connected with a feeding hopper 6-2. The horizontal feeding pipe 6-1 is provided with a feeding spring 6-3.

[0071] The horizontal feeding pipe 6-1 is open at one end and closed at the other end, wherein the open end of the horizontal feeding pipe 6-1 is welded with a roller 9, specifically, as shown in the figure, the pipe opening of the horizontal feeding pipe 6-1 is welded with the outer ring of the roller 9, the feeding spring 6-3 is welded with one side of the inner ring of the roller 9, and the other side of the inner ring of the roller 9 is welded with a connecting pipe 10, the other end of the connecting pipe 10 is connected with the feeding port clamp 5, specifically, the small-diameter end of the feeding port clamp body is clamped into the connecting pipe 10. Figure 5

[0072] The closed end of the horizontal feeding pipe 6-1 is welded with a fixing seat 11, the fixing seat 11 is fixed on the limiting support 3 through bolts, specifically, a plurality of bolt holes are arranged on the limiting support 3 along the length direction, the bolts on the bottom of the fixing seat 11 are inserted into the bolt holes and fastened through nuts, so that the distance between the feeding port clamp 5 and the discharging port clamp 4 can be adjusted according to the length of the pipe to be coated, so as to meet the inner film coating of pipes with different lengths.

[0073] As a preferred embodiment of the present application, the pipe inner film coating device further comprises a fine adjustment assembly 14, the fine adjustment assembly 14 comprises a threaded through hole arranged on the fixing seat 11, then a screw rod passes through the threaded through hole and contacts the end of the horizontal feeding pipe 6-1, when the screw rod is rotated, the horizontal feeding pipe 6-1 will advance or retreat with the rotation of the screw rod, so as to clamp or loosen the pipe, and realize the fine adjustment of the pipe.

[0074] As a preferred embodiment of the present application, the limiting support 3 is slidably provided with an induction coil 12, specifically, a sliding rail 13 is arranged on one of the side walls of the limiting support 3 along the length direction, and a sliding block is fixed on the handle of the induction coil 12, the sliding block is arranged in the sliding rail 13 and can move in the sliding rail 13.

[0075] When the inner film of the pipe is coated, first, the coil of the induction coil 12 is sleeved on the pipe, then the pipe is fixed between the discharging port clamp 4 and the feeding port clamp 5, and the inner film of the pipe is coated.

[0076] The induction coil 12 is used for drying the inner film after the inner film of the pipe is coated, wherein the moving speed is slightly different with the different sintering pipes, and the moving speed is about 60 cm / min.

[0077] The induction coil 12 is a variable frequency induction coil, for example, a 15KW movable electromagnetic induction coil.

[0078] The present application further provides a pipe inner film coating method, which is carried out by using the pipe inner film coating device, and specifically comprises the following steps:

[0079] ​First, the coil of the induction coil 12 is sleeved on the pipeline, then the pipeline is fixed between the inlet clamp 5 and the outlet clamp 4, the motor driving device 7 is started and the rotating speed is adjusted to 0-80 r / min, preferably 40-60 r / min, and the cylinder lifting device 2 is adjusted so that the pipeline is inclined to the horizontal plane at an angle of 0-45°, preferably 15-30°, then the slurry is poured into the feeding device 6 through the feeding funnel 6-2, after the slurry is fully coated on the inner surface of the pipeline, the induction coil 12 is used for heating to discharge the volatile solvent, finally the hydrogen furnace is used for degreasing and low-temperature sintering, and finally the pipeline with the inner film coating is obtained.

[0080] The slurry comprises, by mass percentage, 60wt.-%-70wt.-% of metal powder, 5wt.-%-10wt.-% of binder, 20wt.-%-25wt.-% of organic solvent and 5wt.-%-10wt.-% of pore-forming agent, preferably 65wt.-% of metal powder, 6wt.-% of binder, 24wt.-% of organic solvent and 5wt.-% of pore-forming agent.

[0081] The metal powder comprises 316L stainless steel powder or titanium powder or mixed powder of 316L stainless steel powder and low-melting-point brazing powder, or mixed powder of titanium powder and low-melting-point brazing powder, wherein the mass ratio of 316L stainless steel powder to low-melting-point brazing powder in the mixed powder of 316L stainless steel powder and low-melting-point brazing powder is 3-4:1, and the mass ratio of titanium powder to low-melting-point brazing powder in the mixed powder of titanium powder and low-melting-point brazing powder is 3-4:1. The 316L stainless steel powder and the titanium powder are the main matrix materials and play a main function in the finished product after sintering, and the low-melting-point brazing powder improves the bonding strength when sintering at a relatively low temperature.

[0082] The binder comprises polyvinylpyrrolidone or a mixture of polyvinylpyrrolidone and polyethylene glycol, wherein the mass ratio of polyvinylpyrrolidone to polyethylene glycol in the mixture is 9:1. The binder provides viscosity and flowability for the powder particles, facilitates coating on the inner wall of the pipeline, and the polyethylene glycol can make the particles more uniformly distributed.

[0083] The organic solvent is anhydrous ethanol, which is used for dissolving the binder.

[0084] The pore-forming agent is PMMA microspheres, which increase the porosity of the inner film.

[0085] In the pipeline inner film coating method, an excess amount of slurry is poured into the feeding device, during the inner film coating process, the distribution uniformity and the thickness of the film layer can be maintained by controlling the proportioning of the slurry, the inclination angle of the pipeline and the rotating speed of the motor driving device, after the excess slurry is discharged, the film layer with a thickness of about 100-150 μm can be obtained, and the surface and cross-section micro-morphology of the inner film layer can be observed (as shown in Figure 6The surface presents obvious porous structure, and the combination between powder particles is good, and the pores are also uniformly distributed, and there are many through-hole structures from the surface of the base pipe to the surface of the film layer.

[0086] Example 1

[0087] The pipeline is coated with the pipeline inner film coating equipment, and the pipeline inner film coating equipment comprises the following steps:

[0088] Step 1, respectively, 50g 200 / 300 316L stainless steel powder, 15g nickel-based brazing material powder, 6g polyvinylpyrrolidone, 24g anhydrous ethanol, 5g PMMA microspheres, and mix uniformly to obtain the slurry;

[0089] Step 2, the inner surface of the pipeline to be coated is pickled to remove oil stains, impurities and oxide layer;

[0090] Step 3, first, the coil of the induction coil is sleeved on the pipeline, then the pipeline is fixed between the inlet clamp and the outlet clamp, the fine adjustment assembly is tightened, the pipeline can rotate at a uniform speed following the motor driving device, the motor driving device is adjusted to rotate at 40r / min, the cylinder lifting device is adjusted to lift the pipeline at an angle of 30°, the slurry is injected through the feeding hopper, the excess slurry is discharged from the excess discharge pipe, and the slurry is uniformly coated for about 10min, then the coil heating device is started, the power is set to 15kw, the outer wall surface temperature is kept below 200℃, and the slurry is moved from the inlet end to the outlet end at a speed of about 60cm / min.

[0091] Step 4, the coated pipeline is placed in a 60℃ drying box and dried for 1h, then the pipeline is placed in a hydrogen furnace for degreasing and sintering, and finally a film layer with an average thickness of about 120μm is formed, the film layer is uniform, the thickness range is controlled between 100μm and 150μm, the porosity is about 55%, and the equivalent pore size of the film layer is 30μm.

[0092] Example 2

[0093] According to example 1, the difference between example 1 and example 2 is that the proportion of the binder in the slurry is increased and the amount of powder is reduced, so as to increase the fluidity of the slurry, and the specific steps are as follows:

[0094] Step 1, respectively, 47g 200 / 300 316L stainless steel powder, 13g nickel-based brazing material powder, 10g polyvinylpyrrolidone, 25g anhydrous ethanol, 5g PMMA microspheres, and mix uniformly to obtain the slurry;

[0095] Step 2, the inner surface of the pipeline to be coated is pickled to remove oil stains, impurities and oxide layer;

[0096] Step 3, first put the coil of the induction coil on the pipe, then fix the pipe between the inlet clamp and the outlet clamp, tighten the fine adjustment assembly, so that the pipe can rotate uniformly following the motor drive device, adjust the motor drive device speed to 40r / min, at the same time adjust the cylinder lifting device so that the pipe lifting angle is 30°, inject the slurry through the feeding funnel, the excess slurry will be discharged from the excess discharge pipe, rotate uniformly for about 10min, then start the coil heating device, set the power to 15kw, move from the feeding end to the discharging end, the moving speed is about 60cm / min, keep the outer wall surface temperature below 200℃;

[0097] Step 4, put the coated pipe into a 60℃ drying box and dry for 1h, then perform degreasing and sintering in a hydrogen furnace, finally form a film layer with an average thickness of about 100μm, good uniformity, thickness range controlled between 80μm and 120μm, porosity about 55%, equivalent pore size 30μm film layer product.

[0098]

Example 3

[0099] Referring to Example 1, different from Example 1 is that the proportion of metal powder in the slurry ratio is increased, the amount of binder is reduced, the solid content of the slurry is increased, and the flowability of the slurry itself is reduced, which includes the following steps:

[0100] Step 1, respectively take 55g 200 / 300 mesh 316L stainless steel powder, 15g nickel-based brazing material powder, 5.4g polyvinylpyrrolidone, 0.6g polyethylene glycol, 24g anhydrous ethanol, 5g PMMA microspheres, mechanically stir and mix uniformly to obtain the slurry;

[0101] Step 2, acid wash the inner surface of the pipe to be coated with the inner film to remove oil stains, impurities and oxide layers;

[0102] Step 3, first put the coil of the induction coil on the pipe, then fix the pipe between the inlet clamp and the outlet clamp, tighten the fine adjustment assembly, so that the pipe can rotate uniformly following the motor drive device, adjust the motor drive device speed to 40r / min, at the same time adjust the cylinder lifting device so that the pipe lifting angle is 30°, inject the slurry through the feeding funnel, the excess slurry will be discharged from the excess discharge pipe, rotate uniformly for about 10min, then start the coil heating device, set the power to 15kw, move from the feeding end to the discharging end, the moving speed is about 60cm / min, keep the outer wall surface temperature below 200℃;

[0103] Step 4, the coated pipe is placed into a drying oven at 60℃ for 1h, and then is subjected to debinding and sintering in a hydrogen furnace, finally forming a film layer with an average thickness of about 175μm, good uniformity, thickness range controlled between 150μm-200μm, porosity of about 35%, and equivalent pore diameter of 30μm film layer product.

[0104] [Example 4]

[0105] Referring to Example 1, different from Example 1 is that the amount of pore-forming agent is increased and the mass ratio of metal powder is appropriately reduced in the slurry ratio, and the porosity is increased by introducing more pore-forming agent. The detailed steps are as follows:

[0106] Step 1, respectively take 47g 200 / 300 mesh 316L stainless steel powder, 13g nickel-based brazing material powder, 5.4g polyvinylpyrrolidone, 0.6g polyethylene glycol, 24g anhydrous ethanol, 10g PMMA microspheres, and mechanically mix them uniformly to obtain a slurry.

[0107] Step 2, the inner surface of the pipe to be coated with the inner film is pickled to remove oil stains, impurities and oxide layers;

[0108] Step 3, first put the coil of the induction coil on the pipe, then fix the pipe between the inlet clamp and the outlet clamp, tighten the fine adjustment assembly, so that the pipe can rotate at a constant speed following the motor drive device, adjust the motor drive device speed to 40r / min, at the same time adjust the cylinder lifting device so that the pipe lifting angle is 30°, inject the slurry through the feeding hopper, the excess slurry will be discharged from the excess material discharge pipe, after uniform rotation for about 10min, start the coil heating device, set the power to 15kw, move from the feeding end to the discharging end at a speed of about 60cm / min, keep the outer wall temperature below 200℃;

[0109] Step 4, the coated pipe is placed into a drying oven at 60℃ for 1h, and then is subjected to debinding and sintering in a hydrogen furnace, finally forming a film layer with an average thickness of about 175μm, good uniformity, thickness range controlled between 150μm-200μm, porosity of about 35%, and equivalent pore diameter of 30μm film layer product.

[0110] [Example 5]

[0111] Referring to Example 1, different from Example 1 is that the rotation speed during coating is adjusted to 60r / min, and the rest of the conditions remain unchanged, which includes the following steps:

[0112] Step 1, respectively take 50g 200 / 300 mesh 316L stainless steel powder, 15g nickel-based brazing material powder, 6g polyvinylpyrrolidone, 24g anhydrous ethanol, 5g PMMA microspheres, mix them uniformly to obtain a slurry;

[0113] Step 2, the inner surface of the pipe to be coated with the inner membrane is pickled to remove oil stains, impurities and oxide layers;

[0114] Step 3, first, the coil of the induction coil is sleeved on the pipe, then the pipe is fixed between the inlet clamp and the outlet clamp, the fine adjustment assembly is tightened, the pipe can rotate at a uniform speed following the motor drive device, the motor drive device speed is adjusted to 60 r / min, the cylinder lifting device is adjusted so that the pipe lifting angle is 30°, the slurry is injected through the feeding funnel, the excess slurry is discharged from the excess discharge pipe, after uniform rotation coating for about 10 min, the coil heating device is started, the power is set to 15 kw, the movement speed is about 60 cm / min from the feeding end to the discharging end, the outer wall surface temperature is kept below 200℃;

[0115] Step 4, the coated pipe is placed in a 60℃ drying box and dried for 1 h, then the pipe is placed in a hydrogen furnace for degreasing and sintering, finally the membrane layer with an average thickness of about 120 μm is formed, the membrane layer uniformity is good, the thickness range is controlled between 100 μm and 150 μm, the porosity is about 55%, and the equivalent pore size is 30 μm.

[0116]

Example 6

[0117] Referring to Example 1, the difference between Example 1 and Example 6 is that the inclination angle of the coating equipment is adjusted to 15°, and the other parameters remain unchanged, which includes the following steps in detail:

[0118] Step 1, 50 g of 200 / 300 mesh 316L stainless steel powder, 15 g of nickel-based brazing material powder, 6 g of polyvinylpyrrolidone, 24 g of anhydrous ethanol, and 5 g of PMMA microspheres are weighed respectively and mixed uniformly to obtain a slurry.

[0119] Step 2, the inner surface of the pipe to be coated with the inner membrane is pickled to remove oil stains, impurities and oxide layers;

[0120] Step 3, first, the coil of the induction coil is sleeved on the pipe, then the pipe is fixed between the inlet clamp and the outlet clamp, the fine adjustment assembly is tightened, the pipe can rotate at a uniform speed following the motor drive device, the motor drive device speed is adjusted to 40 r / min, the cylinder lifting device is adjusted so that the pipe lifting angle is 15°, the slurry is injected through the feeding funnel, after uniform rotation coating for about 30 min, the excess slurry is discharged from the excess discharge pipe, the coil heating device is started, the power is set to 15 kw, the movement speed is about 60 cm / min from the feeding end to the discharging end, the outer wall surface temperature is kept below 200℃;

[0121] Step 4, the coated pipe is placed into a 60℃ drying oven for drying for 1h, and then is subjected to degreasing and sintering in a hydrogen furnace, finally forming a film layer with an average thickness of about 150μm, good film layer uniformity, thickness range controlled between 120μm-180μm, porosity of about 47%, and equivalent pore diameter of 27μm film layer product.

[0122] Example 7

[0123] The pipe is coated by using the pipe inner film coating equipment according to the present application, specifically including the following steps:

[0124] Step 1, 52g of 325-mesh spherical titanium powder, 13g of nickel-based brazing material powder, 6g of polyvinylpyrrolidone, 24g of anhydrous ethanol, and 5g of PMMA microspheres are weighed respectively and mixed uniformly to obtain a slurry.

[0125] Step 2, the inner surface of the pipe to be coated is pickled to remove oil stains, impurities and oxide layers;

[0126] Step 3, first, the coil of the induction coil is sleeved on the pipe, then the pipe is fixed between the inlet port clamp and the outlet port clamp, the fine adjustment assembly is tightened, the pipe can rotate at a constant speed following the motor driving device, the motor driving device speed is adjusted to 40r / min, the cylinder lifting device is adjusted so that the pipe lifting angle is 30°, the slurry is injected through the feeding hopper, the excess slurry is discharged from the excess material discharge pipe, after uniform rotation coating for about 10min, the coil heating device is started, the power is set to 15kw, and the moving speed is about 60cm / min from the inlet end to the outlet end, the outer wall surface temperature is kept below 150℃;

[0127] Step 4, the coated pipe is placed into a 60℃ drying oven for drying for 1h, and then is subjected to degreasing and sintering in a hydrogen furnace, finally forming a film layer with an average thickness of about 150μm, good film layer uniformity, thickness range controlled between 120μm-180μm, porosity of about 47%, and equivalent pore diameter of 27μm film layer product.

[0128] Comparative Example 1

[0129] Chinese patent document CN101367127A discloses a centrifugal coating method for preparing heat exchange pipes, which mainly includes:

[0130] Step 1, the slurry is prepared according to a specific proportion, including 8-20wt% of tetraphenyl, dimethylbenzene organic solvent and 2-8wt% of polyphenylethylene, polyvinyl chloride, polypropylene high molecular plastic, and 72-90wt% of 200-400 mesh white copper powder, bronze powder, red copper powder, stainless steel powder and aluminum powder mixed into a paste-like coating mixture to form a paste-like metal powder coating;

[0131] Step 2, after the pipe is filled with the slurry, the pipe is sealed at both ends and rotated at a speed of 1500-2000r / min on a special machine, and then dried.

[0132] Step 3, sintering at 800-1000℃ in a vacuum furnace for 90min, to obtain a porous metal surface in the pipe with a porosity of 30-40%, an average pore size of 50-180μm, and an average thickness of 0.3-0.5mm.

[0133] Compared with Example 1, the method of Comparative Example 1 uses centrifugal coating to prepare a thicker film layer, and generally requires the amount of slurry poured into the pipe to be determined in advance, and less slurry will result in uneven coating. In addition, centrifugal coating requires a higher rotation speed, and has higher requirements for equipment and energy consumption.

[0134]

Comparative Example 2

[0135] Chinese patent document CN1321870A discloses a method for preparing a high-flux heat exchange pipe, and the detailed steps are as follows:

[0136] Step 1, mix the organic binder, brazing material, and metal powder thoroughly, and coat the mixed slurry on the pipe;

[0137] Step 2, dry and pre-solidify the pipe;

[0138] Step 3, transfer the pipe to a high-temperature furnace at 700-1300℃ for brazing, and sinter for 2-10min to form a high-flux pipe with an optimal porosity of 40-65% and a film layer thickness of 0.4mm.

[0139] Compared with Example 1, the method of Comparative Example 2 uses direct coating, and there are many uncertain factors in the control of the thickness of the film layer, the thickness range of the film layer is large, and the film layer is thick. In the use of the enhanced heat exchange pipe, the thick porous layer not only is not conducive to boiling heat transfer, but also becomes a factor hindering heat exchange.

[0140] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0141] In the description of the present application, unless otherwise specified, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0142] The technical solution described above is only one embodiment of the present application. For those skilled in the art, on the basis of the principles disclosed in the present application, various types of improvements or modifications can be easily made, and are not limited to the technical solution described in the above specific embodiments of the present application. Therefore, the foregoing description is only preferred, and is not limiting.

Claims

1. A pipe inner film coating apparatus characterized by comprising: include: A bottom frame, within which a cylinder lifting device is provided; The limiting bracket has one end bottom surface rotatably connected to one end of the bottom frame via three rotating shafts, and the other end bottom surface is provided with a limiting groove along the length direction. The cylinder body of the cylinder lifting device is disposed in the limiting groove, so that the cylinder body can slide in the limiting groove to lift the limiting bracket to 0°~45°. A discharge port clamp is disposed at one end of the limiting bracket and the bottom frame that are rotatably connected, and is fixed to the limiting bracket by a motor drive device. The discharge port clamp includes a discharge port clamp body, which has a central through hole along the axial direction and an annular groove at one end. A step is provided on the outer wall of the discharge port clamp body near the annular groove, and the outer diameter of the discharge port clamp body gradually decreases from the step to the other end, for fixed connection with the motor drive device. The motor drive device is disposed at one end of the limiting bracket and the bottom frame that are rotatably connected, and is welded to the limiting bracket. The smaller outer diameter end of the discharge port clamp is inserted into the hollow roller of the motor drive device, and the other end of the hollow roller of the motor drive device is fixed with a residual material discharge pipe by a thread. The residual material discharge pipe has a discharge through hole along the axial direction. A feed inlet clamp is movably mounted at the other end of the limiting bracket. The feed inlet clamp includes a feed inlet clamp body, one end of which is provided with an annular groove. A central through hole is provided on the feed inlet clamp body along the axial direction, the diameter of which gradually increases from one end of the annular groove to the other end. A step is provided on the outer wall of the feed inlet clamp body, and the outer diameter of the feed inlet clamp body from the annular groove to the step side is greater than the outer diameter from the step to the other end. The end of the feed inlet clamp body with the smaller outer diameter is connected to the feeding device. The feeding device includes a horizontal feeding pipe with one end open and the other end closed. A feeding funnel is connected to the side wall of the horizontal feeding pipe, and a feeding spring is installed inside the horizontal feeding pipe. A roller is welded to the open end of the horizontal feeding pipe, and the feeding spring is welded to one side of the inner ring of the roller. A connecting pipe is welded to the other side of the inner ring of the roller, and the other end of the connecting pipe is connected to the feeding port clamp. A fixing seat is welded to the closed end of the horizontal feeding pipe, and the fixing seat is adjustablely fixed to multiple bolt holes on the limiting bracket by bolts.

2. The in-pipe membrane coating apparatus according to claim 1, wherein The central through hole and the annular groove of the discharge port clamp are arranged on the same axis; A rubber sealing ring is provided inside the annular groove.

3. The in-pipe membrane coating apparatus according to claim 1, wherein A rubber sealing ring is provided in the annular groove of the feed inlet clamp.

4. The in-pipe membrane coating apparatus according to claim 1, wherein The inlet of the horizontal feed pipe is welded to the outer ring of the roller.

5. A method of applying an inner coating to a pipe, characterized by, The coating is performed using the pipe inner membrane coating equipment according to any one of claims 1-4, and the coating method specifically includes the following steps: First, one end of the pipeline is fixed on the discharge port clamp, according to the length of the pipeline, the bolt at the bottom of the fixed seat is inserted into the corresponding bolt hole to fix the pipeline between the inlet clamp and the discharge clamp, the motor drive device is started to adjust the rotating speed to 0-80r / min, the cylinder lifting device is adjusted to make the pipeline with the horizontal plane at 0°-45°, then the slurry is poured into the inlet device through the inlet funnel to realize the coating of the membrane in the pipeline.

6. The in-pipe film coating method according to claim 5, wherein The slurry comprises 60wt.%-70wt.% of metal powder, 5wt.%-10wt.% of binder, 20wt.%-25wt.% of organic solvent and 5wt.%-10wt.% of pore-forming agent by mass percentage.

7. The in-pipe film coating method according to claim 6, wherein The metal powder comprises 316L stainless steel powder or titanium powder or mixed powder of 316L stainless steel powder and low-melting-point brazing powder, or mixed powder of titanium powder and low-melting-point brazing powder, wherein the mass ratio of 316L stainless steel powder to low-melting-point brazing powder in the mixed powder of 316L stainless steel powder and low-melting-point brazing powder is 3-4:1, and the mass ratio of titanium powder to low-melting-point brazing powder in the mixed powder of titanium powder and low-melting-point brazing powder is 3-4:1; The binder comprises polyvinylpyrrolidone or a mixture of polyvinylpyrrolidone and polyethylene glycol, and the mass ratio of polyvinylpyrrolidone to polyethylene glycol in the mixture is 9:1; The organic solvent is anhydrous ethanol; The pore-forming agent is PMMA microspheres.

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