Steady-flow epoxy powder inner spraying equipment special for long and thin steel pipe

Abstract

The utility model discloses a steady-flow epoxy powder inner spraying device special for a long and thin steel pipe, and relates to the technical field of powder inner spraying devices, the steady-flow epoxy powder inner spraying device comprises a powder spraying gun, the powder spraying gun comprises a current stabilizer, an outer pipe, an inner pipe, a gun head connector, a gun head and a spoiler, the outer pipe is arranged on the outer side of the inner pipe in a sleeving mode, and an annular space between the outer pipe and the inner pipe is a cooling cavity; the two ends of the outer pipe and the two ends of the inner pipe are connected with the flow stabilizer and the gun head respectively, the two powder outlet pipes are communicated with the tail of the flow stabilizer, the gun head is installed on the gun head connector, and the turbulator is in a horn shape and inserted into the gun head. One end of the cooling air hose is connected with an air source, and the other end of the cooling air hose is connected to the tail of the outer pipe and communicated with the cooling cavity. An air outlet channel communicated with the cooling cavity is formed in the gun head connector, the outer pipe is sleeved with a plurality of outer pipe heat insulation sleeves, and a heat insulation layer is arranged on the outer wall of the inner pipe; the device is simple in structure, reliable and durable, does not have the phenomena of gun barrel blockage, surge and the like during continuous production and use, and completely meets the requirement of epoxy powder inner spraying of the long and thin steel pipe.

Description

Technical Field

[0001] The invention relates to the technical field of powder internal spraying equipment, and in particular to a steady-flow epoxy powder internal spraying equipment specially used for slender steel pipes. Background Art

[0002] The process flow of epoxy powder internal spraying of steel pipe is as follows: rust removal inside the steel pipe to Sa2.5 level, heat the rust-removed steel pipe to 200℃-275℃, and before the pipe temperature drops to 180℃, spray the epoxy powder evenly on the inner wall of the steel pipe through a spray gun, and keep it warm for 2-3 minutes to allow the powder to fully solidify. The spray layer after solidification should be flat, uniform in color, free of bubbles, cracks and shrinkage holes, and slight orange peel is allowed. The thermal characteristics are greater than 45ΔH (J / g), the non-volatile content is ≥ 99.4%, and the particle size distribution is 150μm. The powder on the sieve is ≤ 3.0%, thickness requirement is greater than 500μm, so it has strict requirements on spraying equipment and spraying process. First of all, the spray gun used must have good heat insulation effect. In the slender tube wall of 275℃, the inner tube temperature shall not be higher than 30℃, so as to avoid premature vulcanization of epoxy powder in the barrel and cause gun blockage; secondly, the spraying airflow pressure and flow rate can always maintain a uniform powder atomization airflow state. Thirdly, sufficient powder spraying amount is required to complete the spraying operation within 1.5-2 minutes. The temperature difference in the whole spraying stage shall not be greater than 50℃, otherwise the tube temperature will drop and the spraying effect will not meet the use requirements.

[0003] The currently used steel pipe epoxy powder internal spraying equipment can meet the requirements when the diameter is greater than 159mm and above. However, with the development of the small-diameter steel pipe anti-corrosion industry in recent years, the anti-corrosion of steel pipes with a length of more than 10m and a diameter of 114mm and below has become more and more popular. Under such working conditions, the existing spraying equipment will quickly transfer heat to the inside of the spray gun due to the overly slender inner hole of the steel pipe, causing the barrel to be blocked; the positive pressure powder spray box will experience a surge effect when connected to a small-diameter spray gun, and the powder atomization airflow pressure and flow cannot maintain a uniform state. The existence of these two phenomena has caused the epoxy powder internal spraying of slender steel pipes to always fail to meet the requirements, becoming a bottleneck restricting the development of the industry. Summary of the invention

[0004] The purpose of the present invention is to provide a special steady-flow epoxy powder internal spraying equipment for slender steel pipes in view of the defects of the prior art.

[0005] The technical scheme of the present invention is: a kind of steady-flow epoxy powder internal spraying equipment specially used for slender steel pipe, comprising an air source, an air intake hose, a Venturi powder pump, a powder box, a powder outlet pipe and a powder spray gun, wherein a plurality of Venturi powder pumps are mounted above the powder box, an air intake end thereof is connected to the air source through an air intake hose, a feed end thereof is connected to a powder intake pipe inserted in the powder box, and a discharge end thereof is connected to the powder spray gun through a powder outlet pipe; the powder spray gun comprises a flow stabilizer, an outer tube, an inner tube, a gun head connection, a gun head and a spoiler, the outer tube is sleeved on the outer side of the inner tube, the two are coaxially arranged, and the annulus between the two is a cooling chamber; the two ends of the outer tube and the inner tube are respectively connected to the flow stabilizer and the gun head connection, a plurality of the powder outlet pipes are connected to the tail of the flow stabilizer, the gun head is mounted on the gun head connection, the spoiler is trumpet-shaped, which is inserted in the gun head, and the annulus between the two is an injection channel;

[0006] It also includes a cooling air hose, one end of which is connected to the air source, and the other end is connected to the tail of the outer tube and communicated with the cooling cavity; an air outlet channel connected to the cooling cavity is provided in the gun head connection, a plurality of outer tube insulation sleeves are mounted on the outer tube, and an insulation layer is provided on the outer wall of the inner tube.

[0007] Preferably, two Venturi powder pumps are provided.

[0008] Preferably, the thermal insulation layer is made of thermal insulation aerogel.

[0009] Preferably, the inner cavity of the flow stabilizer includes a rear cylindrical cavity and a front tapered cavity which is thinner at the front and thicker at the back, and the front end of the cavity is smoothly connected to the inner cavity of the inner tube.

[0010] Preferably, the thickness of the cooling cavity is 8-10 mm.

[0011] Preferably, the axial distance between the front end of the gun tip and the front end of the spoiler is 20-23 mm.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] (1) This device can complete the epoxy powder internal spraying operation of slender steel pipes with a diameter of less than 114mm and a length of 10m-12m within 1.5 minutes. It has a simple structure, is reliable and durable, and has no barrel blockage, surge and other phenomena during continuous production and use. It fully meets the requirements of epoxy powder internal spraying of slender steel pipes, has broad market prospects, and has extremely high economic benefits;

[0014] (2) The air source, air inlet hose, Venturi powder pump, powder outlet pipe and flow stabilizer constitute the epoxy powder negative pressure large flow rate stable pressure outlet device. This set of powder outlet device can stably provide air pressure of 0.2-0.35MPa and flow rate of 3-5Nm 3 / H epoxy powder mixed air flow;

[0015] (3) The powder spray gun adopts triple insulation measures, which fully meets the insulation requirements of the spray gun for epoxy powder internal spraying of slender steel pipes, and there is no barrel clogging. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] In the figure: 1. air source, 2. air inlet hose, 3. venturi powder pump, 4. powder box, 5. powder outlet pipe, 6. powder inlet pipe, 7. flow stabilizer, 701. cylindrical cavity, 702. conical cavity, 8. outer tube, 9. inner tube, 10. outer tube insulation sleeve, 11. insulation layer, 12. gun head connection, 1201. air outlet channel, 13. gun head, 14. spoiler, 15. cooling air hose. DETAILED DESCRIPTION

[0018] The present invention is further described below with reference to the accompanying drawings and embodiments. Embodiment 1

[0019] Reference Figure 1 As shown, a steady-flow epoxy powder internal spraying equipment for slender steel pipes includes an air source 1, an air intake hose 2, a venturi powder pump 3, a powder box 4, a powder outlet pipe 5 and a powder spray gun. Two venturi powder pumps 3 are mounted above the powder box 4, and their air intake ends are connected to the air source 1 through the air intake hose 2, and their feed ends are connected to the powder intake pipe 6 inserted in the powder box 4, and their discharge ends are connected to the powder spray gun through the powder outlet pipe 5; the powder spray gun includes a flow stabilizer 7, an outer tube 8, an inner tube 9, a gun head connection 12, a gun head 13 and a spoiler 14, and the outer The tube 8 is sleeved on the outside of the inner tube 9, and the two are coaxially arranged, and the annulus between the two is a cooling chamber; specifically, the thickness of the cooling chamber is 8-10mm; the two ends of the outer tube 8 and the inner tube 9 are respectively connected to the flow stabilizer 7 and the gun head connection 12, and the two powder outlet pipes 5 are connected to the tail of the flow stabilizer 7, the gun head 13 is installed on the gun head connection 12, the spoiler 14 is trumpet-shaped, and it is inserted in the gun head 13, and the annulus between the two is an injection channel; the axial spacing between the front end of the gun head 13 and the front end of the spoiler 14 is 20-23mm.

[0020] More specifically, the inner cavity of the flow stabilizer 7 includes a rear cylindrical cavity 701 and a front tapered cavity 702, the front end of which is smoothly connected to the inner cavity of the inner tube 9. The air source 1 is connected to the Venturi powder pump 3 through the air inlet hose 2, and the Venturi powder pump 3 is connected to the flow stabilizer 7 through the powder outlet pipe 5 to form an epoxy powder negative pressure type large flow rate stabilized powder outlet device.

[0021] It also includes a cooling air hose 15, one end of which is connected to the air source 1, and the other end is connected to the tail of the outer tube 8 and communicated with the cooling cavity; an air outlet channel 1201 connected to the cooling cavity is provided in the gun head connection 12, a plurality of outer tube insulation sleeves 10 are provided on the outer tube 8, and an insulation layer 11 is provided on the outer wall of the inner tube 9, and the material of the insulation layer 11 is insulation aerogel.

[0022] During the spraying operation, the front stop and the back delay process is adopted. After the powder spray gun passes through the steel pipe from the rear end of the steel pipe, the gun head 13 stops at 100mm away from the front end of the steel pipe, and the air source 1 is turned on. After the powder spraying of the powder spray gun is stable, the powder spray gun moves backward and continuously sprays the inner wall of the steel pipe through the gun head 13; when the powder spray gun completely passes through the steel pipe, it delays and stays for 10-15 seconds to turn off the air source 1, and the spraying operation is completed to ensure that the coating thickness inside the pipe body is consistent.

[0023] Open the air source 1, and the compressed air enters the Venturi powder pump 3 through the air inlet hose 2. The powder is sucked out from the powder box 4 by the Venturi effect to form a mixed gas. The mixed gas enters the inner cavity of the flow stabilizer 7 through the powder outlet pipe 5. The two mixed gases flow steadily in the inner cavity of the flow stabilizer 7 and merge into the inner tube 9 of the powder spray gun. Practice has proved that this powder outlet device can stably provide an air pressure of 0.2-0.35MPa and a flow rate of 3-5Nm 3 / H epoxy powder mixed airflow. The mixed airflow enters the inner tube 9 and the gun head connection 12 in turn, and is finally evenly sprayed on the inner wall of the steel pipe through the gun head 13. The outer tube 8 is equipped with an outer tube insulation sleeve 10, which not only plays the role of the first layer of heat insulation, but also prevents the powder spray gun from wearing during operation. The heat-insulating aerogel layer coated on the surface of the inner tube 9 plays the role of the second layer of heat insulation. A cooling cavity with a thickness of 8-10mm is left between the inner tube 9 and the outer tube 8. After the cooling air passes through the cavity, it is sprayed out through the air outlet channel 1201 to take away the heat. While playing the role of the third layer of heat insulation, it also forms a layer of protective gas on the surface of the gun head 13, which can reduce the deposition and pollution of the powder turbulence on the surface of the gun head 13. Practice has proved that the temperature rise of the inner tube 9 of the powder spray gun does not exceed 28 degrees Celsius when it is in continuous and uninterrupted operation for 16 hours a day, which fully meets the insulation requirements of the spray gun for epoxy powder internal spraying of slender steel pipes.

[0024] In addition, the axial spacing between the front end of the gun head 13 and the front end of the spoiler 14 is 20-23 mm, which can ensure that more than 85% of the mixed powder gas is evenly sprayed on the inner surface of the steel pipe in a fan shape.

[0025] This device can complete the epoxy powder internal spraying operation of slender steel pipes with a diameter of less than 114mm and a length of 10m-12m within 1.5 minutes. It has a simple structure, is reliable and durable, and has no barrel blockage, surging and other phenomena during continuous production and use. It fully meets the requirements of epoxy powder internal spraying of slender steel pipes, has broad market prospects, and has extremely high economic benefits.

[0026] The present invention is not limited to the above-mentioned embodiments. Various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention. The changed contents still fall within the protection scope of the present invention.

Claims

1. A dedicated steady-flow epoxy powder internal spraying equipment for slender steel pipes, comprising an air source, an air inlet hose, a Venturi powder pump, a powder box, a powder outlet pipe and a powder spray gun, wherein a plurality of Venturi powder pumps are mounted above the powder box, wherein the air inlet end thereof is connected to the air source through the air inlet hose, the feed end thereof is connected to a powder feed pipe inserted in the powder box, and the discharge end thereof is connected to the powder spray gun through the powder outlet pipe; the characteristics are as follows: The powder spray gun comprises a flow stabilizer, an outer tube, an inner tube, a gun head connection, a gun head and a spoiler. The outer tube is sleeved on the outer side of the inner tube, the two are coaxially arranged, and the annulus between the two is a cooling chamber; the two ends of the outer tube and the inner tube are respectively connected to the flow stabilizer and the gun head, and the plurality of powder outlet pipes are connected to the tail of the flow stabilizer. The gun head is installed on the gun head connection. The spoiler is trumpet-shaped and inserted in the gun head. The annulus between the two is an injection channel. It also includes a cooling air hose, one end of which is connected to the air source, and the other end is connected to the tail of the outer tube and communicated with the cooling cavity; an air outlet channel connected to the cooling cavity is provided in the gun head connection, a plurality of outer tube insulation sleeves are mounted on the outer tube, and an insulation layer is provided on the outer wall of the inner tube.

2. The steady-flow epoxy powder internal spraying equipment for slender steel pipes according to claim 1 is characterized in that: The Venturi powder pumps are provided with two.

3. The steady-flow epoxy powder internal spraying equipment for slender steel pipes according to claim 1 is characterized in that: The material of the heat insulation layer is heat insulation aerogel.

4. The steady-flow epoxy powder internal spraying equipment for slender steel pipes according to claim 1 is characterized in that: The inner cavity of the flow stabilizer comprises a rear cylindrical cavity and a front tapered cavity which is thin at the front and thick at the back, and the front end of the flow stabilizer is smoothly connected with the inner cavity of the inner tube.

5. The steady-flow epoxy powder internal spraying equipment for slender steel pipes according to claim 1 is characterized in that: The thickness of the cooling cavity is 8-10 mm.

6. The steady-flow epoxy powder internal spraying equipment for slender steel pipes according to claim 1 is characterized in that: The axial distance between the front end of the gun head and the front end of the spoiler is 20-23 mm.

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