Internal rotary spraying and positioning powder supplementing device and spraying method for large-diameter bent pipe

Abstract

The invention relates to the field of inner spraying of steel large-diameter elbows, in particular to an inner rotary spraying and positioning powder supplementing device of a large-diameter elbow, which comprises a rotary powder spraying unit, a positioning powder supplementing unit, a central cylinder unit, an elbow passing unit, a power transmission and powder conveying pipeline, a control unit and a powder supply unit. The positioning powder supplementing unit and the rotary powder spraying unit are sequentially arranged on the center cylinder unit in a sleeving mode from front to back. The center cylinder unit is installed on the elbow passing unit and moves along the interior of the large-diameter elbow under driving of the elbow passing unit. The powder supply unit continuously supplies atomized powder. And the control unit electrically cooperates with the actions of all the units to complete the spraying work of the interior of the large-diameter bent pipe. The invention also comprises a method. Full inner wall spraying and outer side powder supplementing can be completed at a time, the production efficiency is improved, the production cost is reduced, meanwhile, the problem that a coating is thin outside and thick inside is solved, atomized powder is more evenly sprayed to the inner wall of the bent pipe through the powder blowing fan, and the product quality is further improved.

Description

Technical Field

[0001] The invention relates to the field of internal spraying of large-diameter steel elbow pipes, in particular to an internal rotary spraying and positioning powder replenishing device and a spraying method for large-diameter elbow pipes. Background Art

[0002] The elbow is an important part of the conveying pipeline. The elbow is generally made of steel. The elbow spraying can effectively solve the corrosion problem of the conveying medium on the pipe body. The spraying inside the elbow includes phenolic primer spraying and fused epoxy powder spraying. In order to realize the mechanized construction of the spraying inside the elbow, the technicians designed a walking chain car inside the elbow with "snake bone joint + vertical support rod + horizontal limit rod". The ends of the vertical support rod and the horizontal limit rod are equipped with rollers. The front end of the chain car is connected to the machine head, which can ensure that the spraying device can pass freely and be centered in the elbow, which significantly improves the efficiency of spraying inside the elbow.

[0003] The problem with the above-mentioned "snake bone joint + vertical support rod + horizontal limiting rod" device is: since the nozzle is located at the center line of the tube and it is a one-time spraying, the perpendicular bisector of the nozzle end face circle coincides with the perpendicular bisector of the cross-sectional circle of the corresponding curved pipe. When the spraying device works at a uniform speed (the nozzle rotates at a uniform speed and the device moves at a uniform speed), the amount of powder received by the inside and outside of the curved pipe section is the same; the central angle and arc length passed per unit time are the same, but the inner surface area of ​​the outer side of the curved pipe and the inner surface area of ​​the inner side of the curved pipe corresponding to the same central angle are different, and the amount of powder sprayed by the nozzle onto the inner and outer surfaces of the curved pipe during uniform rotation is the same. In this way, during the spraying process inside the curved pipe, although the spraying device moves at a uniform speed and the nozzle rotates at a uniform speed, the coating thickness obtained on the inner and outer inner walls of the curved pipe is different, and this difference becomes more obvious as the diameter of the curved pipe increases. The difference in coating thickness on the inside and outside leads to the following quality problems: when the coating thickness on the inner wall of the elbow is moderate, the coating thickness on the outer wall is insufficient; when the coating thickness on the outer wall of the elbow is moderate, the coating thickness on the inner wall exceeds the standard. If the coating thickness is insufficient, it is unqualified, and if the thickness exceeds the standard, it often causes problems such as powder loss and incomplete sintering. Summary of the invention

[0004] The purpose of the present invention is to provide an internal rotary spraying and positioning powder replenishing device and spraying method for large-diameter elbows, which mainly solves the problems existing in the above-mentioned prior art. It can eliminate the deviation of the inner and outer coating thickness during the internal spraying process of the elbow fittings and avoid the problem of unqualified coating thickness.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide an internal rotary spraying and positioning powder replenishing device for a large-caliber elbow, characterized in that it comprises a rotary powder spraying unit, a positioning powder replenishing unit, a central cylinder unit, an elbow passage unit, a power transmission and powder transmission pipeline, a control unit and a powder supply unit;

[0006] The positioning powder replenishing unit and the rotating powder spraying unit are sequentially mounted on the central cylinder unit from front to back; the central cylinder unit is mounted on the elbow passage unit and moves along the inside of the large-diameter elbow under the drive of the elbow passage unit; the powder supply unit and the external power supply are connected to the rotating powder spraying unit and the positioning powder replenishing unit through the power transmission and powder transmission pipeline to continuously provide power and atomized powder. The control unit is electrically connected to the rotating powder spraying unit, the positioning powder replenishing unit and the elbow passage unit, and coordinates their actions to complete the spraying work inside the large-diameter elbow.

[0007] Furthermore, the rotary powder spraying unit comprises a powder spraying drum, a rotary nozzle, a secondary powder chamber, and a first servo motor; the powder spraying drum is mounted on the central cylinder unit, is rotationally connected to the central cylinder unit through a bearing, and rotates around the central cylinder unit driven by the first servo motor; the inner cavity of the powder spraying drum constitutes the secondary powder chamber; the rotary nozzle is installed on the powder spraying drum and rotates with the powder spraying drum; the rotary nozzle passes through the outer wall of the powder spraying drum and is connected to the secondary powder chamber; the secondary powder chamber is also connected to the inner cavity of the central cylinder unit; a rotary seal is provided at the connection between the powder spraying drum and the central cylinder unit for sealing the secondary powder chamber; the rotary seal is fixed by a pressure cover.

[0008] Furthermore, the first servo motor drives the powder spraying drum to rotate via a V-belt.

[0009] Furthermore, the rotating nozzle is a straight tube and is evenly arranged along the circumference of the powder spraying drum.

[0010] Furthermore, the powder spraying drum is a hollow cylinder with two steps, which is composed of a powder spraying transmission section and a powder spraying working section; the first servo motor drives the powder spraying transmission section to rotate; the powder spraying transmission section then drives the powder spraying working section to rotate; the diameter of the powder spraying working section is larger than that of the powder spraying transmission section; and the secondary powder chamber is located inside the powder spraying working section.

[0011] Furthermore, the positioning powder replenishing unit comprises a plurality of powder replenishing nozzles; the powder replenishing nozzles are installed corresponding to the outer side of the large-diameter curved pipe, and are symmetrically distributed up and down with the horizontal midline of the cross section of the large-diameter curved pipe as the axis of symmetry; the powder replenishing nozzles are connected to the central cylinder unit; the end of the powder replenishing nozzle is bent to form an elbow end, and the powder outlet direction of the powder replenishing nozzle is horizontally pointed toward the rotating powder spraying unit.

[0012] Furthermore, the positioning powder replenishing unit also includes a powder blowing drum, a powder blowing fan blade and a second servo motor; the powder blowing drum is mounted on the central cylinder unit, is rotationally connected to the central cylinder unit through a bearing, and rotates around the central cylinder unit driven by the second servo motor; there are multiple powder blowing fan blades, which are evenly distributed along the radial plane of the powder blowing drum and rotate with the powder blowing drum; the radial length of the powder blowing fan blade is smaller than the radial length of the powder replenishing nozzle, that is, the head of the powder blowing fan blade is located at the lower end of the outlet of the powder replenishing nozzle.

[0013] Furthermore, the powder blowing drum is a two-step cylinder, comprising a powder replenishing transmission section and a powder replenishing working section; the second servo motor drives the powder replenishing transmission section to rotate; the powder replenishing transmission section in turn drives the powder replenishing working section to rotate; the diameter of the powder replenishing working section is larger than that of the powder replenishing transmission section; and the powder blowing fan blades are fixed on the outside of the powder replenishing working section.

[0014] Furthermore, the central cylinder unit comprises a hollow cylinder, a primary powder chamber, a central tube, a front end cover and a rear end cover; the hollow cylinder is coaxially sleeved on the central tube; the hollow cylinder and the central tube themselves do not rotate; the rotary powder spraying unit and the positioning powder replenishing unit are coaxially sleeved on the hollow cylinder, with the central tube as the rotation center; the primary powder chamber is located inside the hollow cylinder; a front end cover and a rear end cover are respectively arranged at the front and rear of the hollow cylinder; the powder supply unit is connected to the primary powder chamber through the rear end cover by means of the power transmission and powder conveying pipeline; the external power supply is connected to the rotary powder spraying unit and the positioning powder replenishing unit through the rear end cover and the front end cover by means of the power transmission and powder conveying pipeline; the positioning powder replenishing unit is connected to the primary powder chamber through the front end cover; the rotary powder spraying unit is installed on the cylinder wall of the hollow cylinder; a connecting slot is arranged on the cylinder wall of the hollow cylinder; the rotary powder spraying unit is connected to the primary powder chamber through the connecting slot.

[0015] The present invention also discloses a method for the internal rotary spraying and positioning powder replenishing device using the large-caliber elbow, which is characterized by comprising the steps of:

[0016] Step S1, the large-diameter elbow to be sprayed is in place;

[0017] Step S2, using the elbow passage unit, push the rotary powder spraying unit, the positioning powder replenishing unit and the central cylinder unit from one end of the large-diameter elbow to the other end, so that the rotary powder spraying unit and the positioning powder replenishing unit extend out of the other end of the large-diameter elbow;

[0018] Step S3, starting the first servo motor in the rotary powder spraying unit through the control unit to drive the powder spraying drum to rotate; starting the second servo motor in the positioning powder replenishing unit through the control unit to drive the powder blowing drum and the powder blowing fan blades to rotate;

[0019] Step S4, the powder supply unit is turned on, and the atomized powder enters the primary powder chamber in the central cylinder unit through the powder conveying pipeline in the power and powder conveying pipeline;

[0020] Step S5, the powder supply unit continues to supply powder, so that the pressure in the primary powder chamber increases, a part of the atomized powder in the primary powder chamber enters the secondary powder chamber located in the rotary powder spraying unit, and the other part enters the positioning powder replenishing unit and is sprayed out from the powder replenishing nozzle; the powder blowing fan blades blow the atomized powder sprayed from the powder replenishing nozzle to the outside direction;

[0021] Step S6, the secondary powder chamber is pressurized, the atomized powder enters the rotary nozzle located around the powder spraying drum from the secondary powder chamber, and is sprayed out from the rotary nozzle;

[0022] Step S7, when the powder output of the rotating nozzle and the powder replenishing nozzle is stable and uniform, the control unit is used to control the elbow passage unit to retreat at a uniform speed in the large-diameter elbow, driving the rotating powder spraying unit and the positioning powder replenishing unit to enter the interior of the large-diameter elbow. During the process, the rotating nozzle is used to spray the inner wall of the large-diameter elbow indiscriminately, and the powder replenishing nozzle is used to spray the outer side of the inner wall of the large-diameter elbow with powder, and the powder blowing fan blades are used to make the atomized powder sprayed from the powder replenishing nozzle evenly adhere to the outer side of the inner wall of the large-diameter elbow;

[0023] Step S8, when the elbow passage unit is retreating at a uniform speed, the control unit is used to adjust the rotation speeds of the first servo motor and the second servo motor, and to control the powder output of the powder supply unit, so as to control the thickness and uniformity of the spraying;

[0024] Step S9, the rotating powder spraying unit, the positioning powder replenishing unit and the central cylinder unit are driven by the elbow passage unit to withdraw from the other end of the large-diameter elbow, and the powder supply unit, the first servo motor and the second servo motor are turned off by the control unit to complete the spraying.

[0025] In view of the above technical features, the internal rotary spraying and positioning powder replenishing device and spraying method for large-diameter elbows of the present invention have the following significant advantages:

[0026] 1. The internal rotary spraying and positioning powder replenishing device for the large-diameter elbow of the present invention has a newly added positioning powder replenishing unit, which is used to replenish powder on the outer side of the inner wall of the large-diameter elbow. Positioning powder replenishing means replenishing powder only on the outer inner pipe wall, and the position of the powder replenishing can be adjusted by controlling the position and quantity of the powder replenishing nozzle. The positioning powder replenishing unit solves the problem of thin outer coating and thick inner coating due to the difference in inner and outer area corresponding to unit time when the existing technology is bending, thereby improving product quality.

[0027] 2. The positioning powder replenishing unit in the internal rotation spraying and positioning powder replenishing device for the large-diameter elbow of the present invention includes, in addition to the powder replenishing elbow, a powder blowing fan composed of a powder blowing drum, a powder blowing fan blade and a second servo motor. By spraying the atomized powder horizontally and then cooperating with the powder blowing fan, the atomized powder can be more evenly and directionally sprayed onto the inner wall of the large-diameter elbow compared to direct spraying, solving the coating uniformity problem of non-rotating positioning spraying.

[0028] 3. The present invention utilizes the internal rotary spraying and positioning powder replenishing device of the large-diameter elbow. As long as the elbow passage unit moves back and forth once in the large-diameter elbow, the entire inner wall spraying and outer side powder replenishing can be completed at one time, thereby improving production efficiency and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a side structural schematic diagram of a preferred embodiment of the internal rotary spraying and positioning powder replenishing device for a large-diameter elbow pipe of the present invention;

[0030] Figure 2 It is a top view of a preferred embodiment of the internal rotary spraying and positioning powder replenishing device for a large-diameter elbow pipe of the present invention;

[0031] Figure 3 It is a side structural schematic diagram of a rotary powder spraying unit, a positioning powder replenishing unit and a central cylinder unit in a preferred embodiment of the internal rotary spraying and positioning powder replenishing device for a large-diameter elbow of the present invention;

[0032] Figure 4 It is a structural schematic diagram of a rotary powder spraying unit, a positioning powder replenishing unit and a central cylinder unit in a preferred embodiment of the internal rotary spraying and positioning powder replenishing device for a large-diameter elbow of the present invention;

[0033] Figure 5 It is a schematic diagram of the installation of a powder replenishing nozzle in a positioning powder replenishing unit in a preferred embodiment of the internal rotary spraying and positioning powder replenishing device for a large-diameter elbow of the present invention;

[0034] Figure 6 The present invention is a method flow chart of a preferred embodiment of the spraying method using the internal rotation spraying and positioning powder replenishing device of a large-diameter elbow.

[0035] In the figure: 100-rotating powder spraying unit, 200-positioning powder replenishing unit, 300-central cylinder unit, 400-elbow passage unit, 500-power transmission and powder transmission pipeline, 600-control unit, 700-powder supply unit, 800-large-diameter elbow;

[0036] 101-powder spraying drum, 102-rotating spraying tube, 103-secondary powder chamber, 104-first servo motor;

[0037] 201-powder replenishing nozzle, 202-powder blowing drum, 203-powder blowing fan blade, 204-second servo motor;

[0038] 301-hollow cylinder, 302-primary powder chamber, 303-central tube, 304-front cover, 305-rear cover, 306-connecting slot;

[0039] 501-powder delivery pipeline, 502-power delivery pipeline;

[0040] 701-Solenoid valve. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0042] See also Figures 1 to 5 The present invention discloses an internal rotary spraying and positioning powder supplying device for a large-caliber elbow. As shown in the figure, a preferred embodiment thereof comprises a rotary powder spraying unit 100, a positioning powder supplying unit 200, a central cylinder unit 300, an elbow passage unit 400, a power transmission and powder supplying pipeline 500, a control unit 600 and a powder supplying unit 700.

[0043] Among them, the elbow passage unit 400 is a moving part, which can move along the central axis of the large-diameter elbow 800 inside the elbow, and is composed of a chain car and a chain car power module. The elbow passage unit 400 is controlled by the control unit 600, and its corresponding control cable passes through the power transmission and powder transmission pipeline 500. The central cylinder unit 300 is installed on the elbow passage unit 400. The rotary powder spraying unit 100 and the positioning powder replenishing unit 200 are sequentially mounted on the central cylinder unit 300. The positioning powder replenishing unit 200 is located at the front of the rotary powder spraying unit 100. During the spraying operation, the elbow passage unit 400 first enters the large-diameter elbow 800, and then retreats to start spraying. Therefore, the rotary powder spraying unit 100 first sprays the inner wall of the large-diameter elbow 800, and then the positioning powder replenishing unit 200 located in front of it (but actually behind the direction of travel) completes the powder replenishing. The equipment for providing power and atomizing powder for the rotary powder spraying unit 100, the positioning powder replenishing unit 200 and the elbow passing unit 400 is located outside the large-diameter elbow 800, so it is necessary to send the external powder to the rotary powder spraying unit 100 and the positioning powder replenishing unit 200 through the power transmission and powder transmission pipeline 500, and at the same time provide power to the rotary powder spraying unit 100, the positioning powder replenishing unit 200 and the elbow passing unit 400. The power transmission and powder transmission pipeline 500 includes a powder transmission pipeline 501 and a power transmission pipeline 502. Among them, the power transmission pipeline 502 also carries a bidirectional control signal. The external power supply enters from the rear end cover 305, passes through the central tube 303, and then passes through the front end cover 304, thereby connecting to the second servo motor 204 located at the front. At the same time, the cable connected to the first servo motor 104 does not need to pass through the rear end cover 305. It does not enter the central tube 303 and is directly connected to the first servo motor 104 from the power transmission pipeline 502. The device that provides atomized powder externally is the powder supply unit 700. The atomized powder enters the powder delivery pipeline 501 after passing through the solenoid valve 701, and finally enters the rotary powder spraying unit 100 and the positioning powder replenishing unit 200. The powder delivery pipeline 501 only needs to pass through the rear end cover 305 to enter the primary powder chamber 302. The entire system is managed by the control unit 600. The control unit 600 is electrically connected to the rotary powder spraying unit 100 and the positioning powder replenishing unit 200 to control their spraying speeds, and is also electrically connected to the elbow passage unit 400 to control its moving speed in the large-diameter elbow 800. By coordinating the actions between the three, the control unit 600 can control the thickness of the powder spraying and powder replenishing inside the large-diameter elbow 800 to meet different needs.

[0044] The rotary powder spraying unit 100 is a device for spraying the inner wall of the large-caliber elbow 800 as a whole. It is composed of a powder spraying drum 101, a rotating nozzle 102, a secondary powder chamber 103 and a first servo motor 104. The powder spraying drum 101 is mounted on the central cylinder unit 300 and connected to the central cylinder unit 300 by a bearing. After the powder spraying drum 101 is connected and installed, the powder spraying drum 101 can rotate freely around the central cylinder unit 300. The powder spraying drum 101 is a hollow cylinder with two steps, which is made of 42CrMo steel bar material and has a length of 120mm. It is composed of a powder spraying transmission section and a powder spraying working section. Among them, the length of the powder spraying working section is 60mm, the length of the powder spraying transmission section is 60mm, and the diameter of the powder spraying working section is larger than the powder spraying transmission section. The power device connected to the powder spraying transmission section is driven to rotate by the power device and then drives the powder spraying working section to rotate. The first servo motor 104 is the power source for driving the powder-spraying drum 101 to rotate. It uses the Huichuan MS1H3 series and is located below the rear end of the central cylinder unit 300, and is connected and fixed to the central cylinder unit 300 and the supporting components. It transmits power through a V-belt, is connected to the powder transmission section of the powder-spraying drum 101, and drives the powder-spraying drum 101 to rotate around the central cylinder unit 300. On the outer wall of the powder-spraying drum 101, a plurality of rotating nozzles 102 are evenly arranged along the circumference of the powder-spraying drum 101. The rotating nozzle 102 is a straight pipe, one end of which passes through the outer wall of the powder-spraying drum 101, and the other end is perpendicular to the inner wall of the large-diameter elbow 800. The rotating nozzle 102 uses a UPVC pipe with an inner diameter of 32 mm, and 28 are set. The inside of the powder-spraying working section of the powder-spraying drum 101 becomes a secondary powder chamber 103. After the rotating nozzle 102 passes through the outer wall of the powder spraying drum 101, it enters the secondary powder chamber 103, thereby extracting the atomized powder in the secondary chamber 103 and spraying it out from the other end. During the spraying process, the rotating nozzle 102 is driven to rotate by the powder spraying drum 101, thereby throwing the atomized powder on the inner wall of the large-caliber elbow 800. At the position where the central cylinder unit 300 contacts the secondary powder chamber 103, a connecting slot 306 is set on the cylinder wall of the central cylinder unit 300, which is used to connect the secondary powder chamber 103 with the primary powder chamber 302 inside the central cylinder unit 300. There are multiple connecting slots 306, and the number and position correspond to the secondary powder chamber 103 one by one, which is a double-row design. The central angle corresponding to a single slot is 45 degrees, and 6 slots are arranged in a single circle, and the width of each slot is 12mm. In this way, the primary powder chamber 302 at the center of the central cylinder unit 300 is connected to the secondary powder chamber 103 through the connecting slot 306. After the atomized powder from the powder supply unit 700 is pressurized, it reaches the primary powder chamber 302 along the power transmission and powder delivery pipeline 500, then enters the secondary powder chamber 103 through the connecting slot 306, and finally is sprayed from the top of the rotary nozzle 102 to the inner wall of the large-diameter elbow 800. A rotary seal is installed at the connection between the end of the powder spraying drum 101 and the central cylinder unit 300 to seal the secondary powder chamber 103.The rotating seal is fixed by a gland on the outer side of the rotating seal.

[0045] The positioning powder replenishing unit 200 comprises a plurality of powder replenishing nozzles 201, a powder blowing drum 202, a powder blowing blade 203 and a second servo motor 204. The powder replenishing nozzles 201 are used to replenish powder for the outer side of the inner wall of the large-diameter elbow 800, so they are installed corresponding to the outer side of the large-diameter elbow 800, and are symmetrically distributed up and down with the horizontal midline of the cross section of the large-diameter elbow 800 as the symmetry axis. The powder replenishing nozzles 201 are connected to the primary powder chamber 302 in the central cylinder unit 300, and atomized powder is directly obtained from the primary powder chamber 302. The end of the powder replenishing nozzle 201 is bent to form an elbow end, and the elbow end is consistent with the axial direction of the central cylinder unit, that is, the direction of the elbow end outlet is horizontally directed to the rotary powder spraying unit 100. The powder replenishing nozzles 201 are made of UPVC pipes, and 7 are set. The powder blowing drum 202, the powder blowing blade 203 and the second servo motor 204 jointly constitute a powder blowing fan. The powder blowing drum 202 is mounted on the central cylinder unit 300 and connected to the central cylinder unit 300 through a bearing. After the powder blowing drum 202 is connected and installed, the powder blowing drum 202 can rotate freely around the central cylinder unit 300. The powder blowing drum 202 is also a two-step cylinder, which is made of 42CrMo steel bar material, with a length of 80mm, and includes a powder replenishing transmission section and a powder replenishing working section. The second servo motor 204 uses Huichuan MS1H3 series, is located below the front end of the central cylinder unit 300, and is connected and fixed to the central cylinder unit 300, and is connected and driven by a V-belt to rotate the powder replenishing transmission section, thereby driving the powder replenishing working section to rotate. Among them, the powder replenishing working section 2 is 40mm long, the powder replenishing transmission section is 40mm, and the diameter of the powder replenishing working section is larger than the powder replenishing transmission section. On the outside of the powder replenishing working section, a plurality of powder blowing blades 203 are evenly arranged along the radial plane of the powder blowing drum 202. Specifically, the powder blowing blades 203 are made of PVC material, and the number is 28. When the second servo motor 204 drives the powder blowing drum 202 to rotate around the central cylinder unit, the powder blowing blades 203 are driven to rotate together to form a fan configuration. The radial length of the powder blowing blades 203 is smaller than the radial length of the powder replenishing nozzle 201, that is, the head of the powder blowing blades 203 is located at the lower end of the outlet of the powder replenishing nozzle 201. After the powder blowing blades 203 rotate, an outward rotating wind flow is formed in the circumferential direction, so that the atomized powder sprayed by the powder replenishing nozzle 201 is more evenly attached to the outer inner wall of the large-diameter elbow 800.

[0046] The central cylinder unit 300 is composed of a hollow cylinder 301, a primary powder chamber 302, a central tube 303, a front cover 304 and a rear cover 305. The hollow cylinder 301 is made of 42CrMo steel bar material, with a length of 300mm, an outer diameter of 312mm, a wall thickness of 6mm, and is coaxially mounted on the central tube 303. The central tube 303 is made of stainless steel, with an outer diameter of 25mm and a wall thickness of 0.6mm, and is connected and sealed with the front cover 304 and the rear cover 305 by threads and sealant. The hollow cylinder 301 and the central tube 303 do not rotate by themselves. They are fixedly connected to the elbow passage unit 400 and move forward and backward with the elbow passage unit 400 in the large-diameter elbow 800. The central tube 303 is the rotation center of the rotary powder spraying unit 100 and the positioning powder replenishing unit 200, and they are coaxially mounted on the hollow cylinder 301. The primary powder chamber 302 is also coaxially mounted with the central tube 303 and is located inside the hollow cylinder 301. A front cover 304 and a rear cover 305 are respectively arranged at the front and rear of the hollow cylinder 301, and are threadedly connected to the hollow cylinder 301. The central tube 303 penetrates the front cover 304 and the rear cover 305 at both ends. The primary powder chamber 302 itself does not rotate either. It is connected to the external powder supply unit 700 through the power transmission and powder transmission pipeline 500 to obtain a continuous supply of pressurized atomized powder.

[0047] Ten rubber hoses with an inner diameter of 40 mm are used to supply powder between the primary powder chamber 302 and the powder supply unit 700. The power transmission and powder delivery pipeline 500 passes through the hollow cylinder 301 through the powder delivery pipe inlet on the rear end cover 305. The positioning powder replenishment unit 200 passes through the powder outlet on the front end cover 304 and is connected to the primary powder chamber 302. A UPVC pipe with an inner diameter of 32 mm is used to connect the positioning powder replenishment unit 200 and the primary powder chamber 302. The secondary powder chamber 103 in the rotary powder spraying unit 100 passes through the hollow cylinder 301 through the connecting slot 306 and is connected to the primary powder chamber 302, so as to continuously obtain a supply of atomized powder from the primary powder chamber 302.

[0048] See also Figure 6 The present invention also discloses a method for spraying an inner rotary spraying and positioning powder replenishing device using the above-mentioned large-caliber elbow, a preferred embodiment of which comprises the steps of:

[0049] Step S100, the large-diameter elbow to be sprayed is in place.

[0050] Step S200, entering into the preparation operation.

[0051] By using the elbow passage unit, the rotary powder spraying unit, the positioning powder replenishing unit and the central cylinder unit are pushed from one end of the large-diameter elbow to the other end, so that the rotary powder spraying unit and the positioning powder replenishing unit extend out of the other end of the large-diameter elbow.

[0052] Step S300, starting the rotary powder spraying unit and the positioning powder replenishing unit.

[0053] The first servo motor in the rotary powder spraying unit is turned on by the control unit to drive the powder spraying drum to rotate; the second servo motor in the positioning powder replenishing unit is turned on to drive the powder blowing drum to rotate.

[0054] Step S400, starting the powder supply unit.

[0055] The powder supply unit is connected, the solenoid valve is opened, and the atomized powder is pressurized and enters the primary powder chamber in the central cylinder unit through the powder conveying pipeline in the power supply and powder conveying pipeline.

[0056] Step S500: the powder replenishing unit to be positioned is stable.

[0057] The powder supply unit continues to supply powder to the primary powder chamber, thereby increasing the pressure in the primary powder chamber. Under the action of pressure, part of the atomized powder in the primary powder chamber enters the secondary powder chamber located in the rotary powder spraying unit, and the other part enters the positioning powder replenishing unit and is sprayed out from the powder replenishing nozzle; the powder blowing drum drives the powder blowing fan blades to rotate, blowing the atomized powder sprayed from the powder replenishing nozzle toward the outer wall of the corresponding large inner diameter elbow.

[0058] Step S600, waiting for the rotary powder spraying unit to be stable.

[0059] The secondary powder chamber is pressurized, and the atomized powder enters the rotary nozzle around the rotary powder spraying unit from the secondary powder chamber and is sprayed out from the rotary nozzle.

[0060] Step S700, starting the spraying operation.

[0061] When the powder output of the rotary nozzle and the powder replenishing nozzle is stable and uniform, the elbow passage unit is used to retreat at a uniform speed to drive the rotary powder spraying unit and the positioning powder replenishing unit to enter the interior of the large inner diameter elbow, and the rotary nozzle is used to start indiscriminate spraying on the inner wall of the elbow, and the powder replenishing nozzle is used to spray powder on the inner and outer walls of the elbow, and the powder blowing fan blades are used to make the atomized powder more evenly adhere to the inner wall of the corresponding large-diameter elbow.

[0062] Step S800, dynamically adjusting spraying parameters.

[0063] When the elbow passage unit retreats at a uniform speed, the control unit is used to adjust the rotation speeds of the first servo motor and the second servo motor, and to control the powder output of the powder supply unit, thereby controlling the thickness and uniformity of the spraying.

[0064] Step S900, spraying is completed.

[0065] When the rotary powder spraying unit, the positioning powder replenishing unit and the central cylinder unit are driven by the elbow passage unit to withdraw from one end of the large-diameter elbow, the powder supply unit, the first servo motor and the second servo motor are closed by the control unit to complete the spraying.

[0066] The following demonstrates the effect of using this embodiment on a seamless elbow of D1016*12.5mm and 90° bend. The inner diameter of the seamless elbow of D1016*12.5mm and 90° bend is 991mm. First, it is subjected to shot peening and rust removal, and the tube body is heated. Then, the inner wall of the elbow is sprayed with phenolic primer and fused epoxy powder in turn. After the fused epoxy powder spraying step is completed, the spraying effect is subjected to surface quality inspection and thickness inspection. The results show that the appearance of the spray coating is smooth and beautiful, without the phenomenon of powder falling and powder piling. The detection value of the inner coating thickness of the elbow is 150 microns, and the detection value of the outer coating thickness is 152 microns. The difference in thickness between the inner and outer coatings is 2 microns, and the difference in thickness between the inner and outer coatings is basically eliminated.

[0067] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An internal rotary spraying and positioning powder replenishing device for large-caliber elbows, characterized in that: It includes a rotary powder spraying unit, a positioning powder supplying unit, a central cylinder unit, a bend passage unit, a power transmission and powder transmission pipeline, a control unit and a powder supply unit; The positioning powder replenishing unit and the rotating powder spraying unit are sequentially mounted on the central cylinder unit from front to back; the central cylinder unit is mounted on the elbow passage unit and moves along the inside of the large-diameter elbow under the drive of the elbow passage unit; the powder supply unit and the external power supply are connected to the rotating powder spraying unit and the positioning powder replenishing unit through the power transmission and powder transmission pipeline to continuously provide power and atomized powder. The control unit is electrically connected to the rotating powder spraying unit, the positioning powder replenishing unit and the elbow passage unit, and coordinates their actions to complete the spraying work inside the large-diameter elbow.

2. The internal rotary spraying and positioning powder supply device for large-diameter elbow pipes according to claim 1, characterized in that: The rotary powder spraying unit comprises a powder spraying drum, a rotary nozzle, a secondary powder chamber, and a first servo motor; the powder spraying drum is mounted on the central cylinder unit, is rotationally connected to the central cylinder unit through a bearing, and rotates around the central cylinder unit driven by the first servo motor; the inner cavity of the powder spraying drum constitutes the secondary powder chamber; the rotary nozzle is installed on the powder spraying drum and rotates with the powder spraying drum; the rotary nozzle passes through the outer wall of the powder spraying drum and is connected to the secondary powder chamber; the secondary powder chamber is also connected to the inner cavity of the central cylinder unit; a rotary seal is provided at the connection between the powder spraying drum and the central cylinder unit for sealing the secondary powder chamber; the rotary seal is fixed by a pressure cover.

3. The internal rotary spraying and positioning powder replenishing device for large-diameter elbow pipes as claimed in claim 2, characterized in that: The first servo motor drives the powder spraying drum to rotate via a V-belt.

4. The internal rotary spraying and positioning powder replenishing device for large-diameter elbow pipes as claimed in claim 2, characterized in that: The rotating nozzle is a straight tube and is evenly arranged along the circumference of the powder spraying drum.

5. The internal rotary spraying and positioning powder supply device for large-diameter elbow pipes as claimed in claim 2, characterized in that: The powder spraying drum is a hollow cylinder with two steps, which is composed of a powder spraying transmission section and a powder spraying working section; the first servo motor drives the powder spraying transmission section to rotate; the powder spraying transmission section then drives the powder spraying working section to rotate; the diameter of the powder spraying working section is larger than that of the powder spraying transmission section; the secondary powder chamber is located inside the powder spraying working section.

6. The internal rotary spraying and positioning powder supply device for large-diameter elbow pipes according to claim 1, characterized in that: The positioning powder replenishing unit comprises a plurality of powder replenishing nozzles; the powder replenishing nozzles are installed corresponding to the outer side of the large-diameter elbow, and are symmetrically distributed up and down with the horizontal midline of the cross section of the large-diameter elbow as the symmetry axis; the powder replenishing nozzles are connected to the central cylinder unit; the end of the powder replenishing nozzle is bent to form an elbow end, and the powder outlet direction of the powder replenishing nozzle is horizontally directed to the rotating powder spraying unit.

7. The internal rotary spraying and positioning powder replenishing device for large-diameter elbow pipes as claimed in claim 6, characterized in that: The positioning powder replenishing unit also includes a powder blowing drum, a powder blowing fan blade and a second servo motor; the powder blowing drum is mounted on the central cylinder unit, is rotationally connected to the central cylinder unit through a bearing, and rotates around the central cylinder unit driven by the second servo motor; there are multiple powder blowing fan blades, which are evenly distributed along the radial plane of the powder blowing drum and rotate together with the powder blowing drum; the radial length of the powder blowing fan blade is smaller than the radial length of the powder replenishing nozzle, that is, the head of the powder blowing fan blade is located at the lower end of the outlet of the powder replenishing nozzle.

8. The internal rotary spraying and positioning powder supply device for large-diameter elbow pipes as claimed in claim 6, characterized in that: The powder blowing drum is a two-step cylinder, comprising a powder replenishing transmission section and a powder replenishing working section; the second servo motor drives the powder replenishing transmission section to rotate; the powder replenishing transmission section then drives the powder replenishing working section to rotate; the diameter of the powder replenishing working section is larger than that of the powder replenishing transmission section; the powder blowing fan blades are fixed on the outside of the powder replenishing working section.

9. The internal rotary spraying and positioning powder supply device for large-diameter elbow pipes as claimed in claim 1, characterized in that: The central cylinder unit comprises a hollow cylinder, a primary powder chamber, a central tube, a front end cover and a rear end cover; the hollow cylinder is coaxially sleeved on the central tube; the hollow cylinder and the central tube do not rotate themselves; the rotary powder spraying unit and the positioning powder replenishing unit are coaxially sleeved on the hollow cylinder, with the central tube as the rotation center; the primary powder chamber is located inside the hollow cylinder; a front end cover and a rear end cover are respectively arranged at the front and rear of the hollow cylinder; the powder supply unit is connected to the primary powder chamber through the rear end cover by means of the power transmission and powder conveying pipeline; the external power supply is connected to the rotary powder spraying unit and the positioning powder replenishing unit through the rear end cover and the front end cover by means of the power transmission and powder conveying pipeline; the positioning powder replenishing unit is connected to the primary powder chamber through the front end cover; the rotary powder spraying unit is installed on the cylinder wall of the hollow cylinder; a connecting slot is arranged on the cylinder wall of the hollow cylinder; the rotary powder spraying unit is connected to the primary powder chamber through the connecting slot.

10. A method for using the internal rotary spraying and positioning powder replenishing device of the large-diameter elbow as claimed in claim 1, characterized in that: Contains steps: Step S1, the large-diameter elbow to be sprayed is in place; Step S2, using the elbow passage unit, push the rotary powder spraying unit, the positioning powder replenishing unit and the central cylinder unit from one end of the large-diameter elbow to the other end, so that the rotary powder spraying unit and the positioning powder replenishing unit extend out of the other end of the large-diameter elbow; Step S3, starting the first servo motor in the rotary powder spraying unit through the control unit to drive the powder spraying drum to rotate; starting the second servo motor in the positioning powder replenishing unit through the control unit to drive the powder blowing drum and the powder blowing fan blades to rotate; Step S4, the powder supply unit is turned on, and the atomized powder enters the primary powder chamber in the central cylinder unit through the powder conveying pipeline in the power and powder conveying pipeline; Step S5, the powder supply unit continues to supply powder, so that the pressure in the primary powder chamber increases, a part of the atomized powder in the primary powder chamber enters the secondary powder chamber located in the rotary powder spraying unit, and the other part enters the positioning powder replenishing unit and is sprayed out from the powder replenishing nozzle; the powder blowing fan blades blow the atomized powder sprayed from the powder replenishing nozzle to the outside direction; Step S6, the secondary powder chamber is pressurized, the atomized powder enters the rotary nozzle located around the powder spraying drum from the secondary powder chamber, and is sprayed out from the rotary nozzle; Step S7, when the rotating nozzle and the powder replenishing nozzle discharge powder stably and evenly, the control unit is used to control the elbow passage unit to retreat at a uniform speed in the large-diameter elbow, driving the rotating powder spraying unit and the positioning powder replenishing unit to enter the interior of the large-diameter elbow. During the process, the rotating nozzle is used to spray the inner wall of the large-diameter elbow indiscriminately, and the powder replenishing nozzle is used to spray the outer side of the inner wall of the large-diameter elbow with powder, and the powder blowing blade is used to make the atomized powder sprayed from the powder replenishing nozzle evenly adhere to the outer side of the inner wall of the large-diameter elbow; Step S8, when the elbow passage unit is retreating at a uniform speed, the control unit is used to adjust the rotation speeds of the first servo motor and the second servo motor, and to control the powder output of the powder supply unit, so as to control the thickness and uniformity of the spraying; Step S9, the rotating powder spraying unit, the positioning powder replenishing unit and the central cylinder unit are driven by the elbow passage unit to withdraw from the other end of the large-diameter elbow, and the powder supply unit, the first servo motor and the second servo motor are turned off by the control unit to complete the spraying.

Images