Method for processing a steel pipe glass fiber reinforced plastic protective layer

Abstract

This invention belongs to the field of steel pipe processing technology, specifically relating to a processing method for a fiberglass protective layer on steel pipes. It aims to solve the problems of long curing cycles, low production efficiency, incomplete liquid epoxy impregnation, and easy peeling of the protective layer in traditional fiberglass protective layer processing techniques. This invention includes steps such as: applying an anti-corrosion layer, rolling the protective layer, and cooling and curing. The fiberglass protective layer provided by this invention exhibits stronger cross-linking and tighter bonding between the base anti-corrosion layer, epoxy layer, and fiberglass fiber layer, resulting in superior adhesion compared to traditional liquid epoxy fiberglass protective layers.

Description

Technical Field

[0001] This invention belongs to the field of steel pipe processing technology, and specifically relates to a processing method for a fiberglass protective layer on steel pipes. Background Technology

[0002] The outer layer of fiberglass reinforced plastic (FRP) is typically used to protect steel pipes during directional crossings of steel pipe pile foundations and pipelines, preventing damage to the steel pipe substrate and anti-corrosion coating.

[0003] The existing method for applying fiberglass protective coatings to steel pipe pile foundations and directional pipelines involves alternating layers of liquid epoxy resin and fiberglass cloth, allowing them to interpenetrate and cross-link to form a composite coating. This method places the steel pipe on a rotating roller or similar platform, rotating it in place. A base layer of liquid epoxy is applied manually or using automated spraying equipment, followed by tight wrapping of fiberglass cloth. This process is repeated until the required number and thickness of composite coating layers are achieved. After coating, the pipe needs to be hoisted onto a support structure for curing, which typically takes more than 24 hours. During this time, the pipes cannot be stacked, as this will damage the coating and render it unusable. This method has low production efficiency per unit and requires a large area for curing.

[0004] Moreover, in this process, because glass fiber and epoxy materials cannot effectively adhere to the steel pipe substrate, a certain tension needs to be applied during the winding process to ensure that the liquid epoxy coating fully penetrates the fiberglass mesh; otherwise, delamination and peeling will occur.

[0005] Overall, the traditional layer-by-layer winding process carries relatively high quality risks. It is prone to incomplete impregnation of liquid epoxy, resulting in adhesion failure in pull-out tests and the loss of protective layer during the construction process, leading to the scrapping of the pipe. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, namely the long curing cycle, low production efficiency, incomplete liquid epoxy impregnation, and easy peeling of the protective layer in the traditional fiberglass protective layer processing technology, this invention provides a processing method for fiberglass protective layers on steel pipes.

[0007] The technical solution of the present invention includes:

[0008] A method for processing a fiberglass protective layer for steel pipes, characterized by comprising the following steps:

[0009] (1) Preparations before coating the steel pipe, including pipe cutting and rust removal;

[0010] (2) Applying anti-corrosion coating: Heat the pipe body after rust removal and apply fusion bonded epoxy powder coating or 3PE coating.

[0011] (3) Protective layer rolling: The thermosetting epoxy fiberglass prepreg tape is continuously wound onto the surface of the steel pipe coated with anti-corrosion layer using a prepreg tape feeding device.

[0012] (4) Cutting: Cut the steel pipe after the thermosetting epoxy fiberglass prepreg tape is wrapped.

[0013] (5) Cooling and curing: Cooling and curing the thermosetting epoxy fiberglass prepreg tape coating on the surface of the steel pipe;

[0014] (6) Warehouse entry: Trim and package the cooled and solidified protective layer steel pipes at the pipe ends, and then store them in the warehouse for stacking.

[0015] As an optional technical solution, in step (2), the steel pipe body is heated to 210℃-240℃ using a medium-frequency heating method.

[0016] As an alternative technical solution, in step (2), plasma surface polarization is performed online immediately after the 3PE coating is formed.

[0017] As an optional technical solution, in step (3), the prepreg tape feeding device includes two or more feeding chucks, and each feeding chuck alternately feeds and winds the material.

[0018] As an optional technical solution, the prepreg tape feeding device also includes a pressure roller to ensure that the prepreg tape is under certain pressure after being wound on the steel pipe, so that the prepreg tape is tightly attached to the surface of the anti-corrosion layer.

[0019] As an alternative technical solution, the prepreg tape is a combination of epoxy elastomer and fiberglass cloth.

[0020] As an alternative technical solution, when the prepreg tape is wound, the outer surface temperature of the steel pipe containing the anti-corrosion layer is 200℃-240℃.

[0021] As an optional technical solution, in step (5), the interval between the completion of the thermosetting epoxy fiberglass prepreg winding and the cooling time is 1-1.5 minutes to ensure that the prepreg and the anti-corrosion layer react fully.

[0022] As an optional technical solution, in step (5), the cooling adopts a spray-type water cooling system.

[0023] As an alternative technical solution, a conveyor belt for conveying steel pipes is also included. The conveyor belt consists of several conveyor rollers, wherein some conveyor rollers maintain the steel pipe's rotation around its axis by rotating on their own, and some conveyor rollers maintain the steel pipe's linear movement along its own axis by rotating on their own.

[0024] The beneficial effects of this invention are:

[0025] (1) The processing method of the steel pipe fiberglass protective layer provided by the present invention realizes the continuous application of epoxy coating and 3PE coating or epoxy fiberglass coating.

[0026] (2) The processing method of the steel pipe fiberglass protective layer provided by the present invention realizes the rapid curing of the epoxy fiberglass protective layer in the range of 200℃-240℃, and the curing time is shortened to less than 1.5 minutes.

[0027] (3) The processing method of steel pipe fiberglass protective layer provided by the present invention realizes factory assembly line production, greatly improves production efficiency, and improves product appearance quality and internal quality.

[0028] (4) The processing method of steel pipe fiberglass protective layer provided by the present invention allows the finished product to be directly stacked, reducing storage difficulty and risk.

[0029] (5) The processing method of the steel pipe fiberglass protective layer provided by the present invention has a stronger cross-linking effect and tighter bonding between the base anti-corrosion layer, epoxy layer and fiberglass fiber layer of the fiberglass protective layer produced by the method, and the adhesion is better than that of the traditional liquid epoxy fiberglass protective layer. Detailed Implementation

[0030] The present application will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0032] This invention provides a method for processing a fiberglass protective layer for steel pipes.

[0033] The processing method for the fiberglass protective layer of steel pipe provided by this invention allows both the anti-corrosion layer and the fiberglass protective layer on the outer surface of the steel pipe to be continuously coated on a 3PE production line. The production line can be based on the 3PE production line and can be equipped with a plasma surface polarization device, a thermosetting epoxy fiberglass prepreg tape feeding device, a cutting device, and a water spraying chamber, which can move the water spraying area back by 1m-1.5m.

[0034] For 3PE coatings, full-surface plasma polarization treatment can be performed online immediately after molding.

[0035] This invention utilizes a prepreg tape feeding device with two or more sets of feeding chucks to continuously wind thermosetting epoxy fiberglass prepreg tape rolls around the outside of anticorrosion steel pipes. Each feeding chuck feeds material alternately to achieve continuous winding. The feeding device is equipped with pressure rollers and applies pressure to ensure that the prepreg tape adheres tightly to the surface of the anticorrosion layer.

[0036] The thermosetting epoxy fiberglass prepreg tape roll of the present invention can be selected from the thermosetting reinforced fiber composite tape products commercially available from Jiangsu Xiude Materials Technology Co., Ltd.

[0037] When thermosetting epoxy fiberglass prepreg is wrapped, the outer surface temperature of the anti-corrosion layer is 200℃-240℃.

[0038] The process of this invention includes:

[0039] (1) After the rust-removed steel pipe is heated by medium frequency, the temperature rises to 210℃-240℃, and then fusion-bonded epoxy powder coating or 3PE coating is applied.

[0040] (2) For 3PE coating, plasma surface polarization is performed online immediately after molding to improve its adhesion to epoxy material. This process is carried out continuously during production. For fusion bonded epoxy powder coating, no surface polarization treatment is required.

[0041] (3) Using a prepreg tape feeding device, thermosetting epoxy fiberglass prepreg tape rolls are continuously wound around the outside of the anti-corrosion steel pipe. The outer surface temperature of the anti-corrosion pipe is between 200℃ and 240℃. Since the steel pipe is rotating and advancing on the transmission line, the prepreg tape can be wound evenly and continuously on the outside of the steel pipe. The pitch and the number of prepreg tape overlap layers can be adjusted by customizing the prepreg tape width, setting the steel pipe advancing speed and rotation speed.

[0042] (4) The feeding device is equipped with two sets of feeding chucks, which are used alternately to achieve continuous feeding. The feeding device is equipped with pressure rollers to apply a certain pressure, which can make the prepreg tape adhere tightly to the surface of the anti-corrosion layer.

[0043] (5) The steel pipe passes continuously from end to end on the transmission line. When it is wound to the joint, it is cut off by the cutting device.

[0044] (6) After the thermosetting epoxy fiberglass prepreg tape is wrapped, continue to move forward for about 1 minute to allow for a full reaction. The water cooling system inherent in the 3PE production line can be used to cool it down to room temperature.

[0045] (7) After the pipe end is trimmed and packaged, the product can be stacked.

[0046] In the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0048] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0049] It will be readily understood by those skilled in the art that the scope of protection of this invention is obviously not limited to these specific embodiments. Without departing from the principles of this invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions resulting from such changes or substitutions will all fall within the scope of protection of this invention.

Claims

1. A method for processing a fiberglass protective layer on a steel pipe, characterized in that, Includes the following steps: (1) Preparations before coating the steel pipe, including pipe cutting and rust removal; (2) Applying anti-corrosion coating: Heat the pipe body after rust removal and apply fusion bonded epoxy powder coating or 3PE coating. (3) Protective layer rolling: The thermosetting epoxy fiberglass prepreg tape is continuously wound onto the surface of the steel pipe coated with anti-corrosion layer using a prepreg tape feeding device. (4) Cutting: Cut the steel pipe after the thermosetting epoxy fiberglass prepreg tape is wrapped. (5) Cooling and curing: Cooling and curing the thermosetting epoxy fiberglass prepreg tape coating on the surface of the steel pipe; (6) Warehouse entry: Trim and package the cooled and solidified protective layer steel pipes at the pipe ends, and then store them in the warehouse for stacking.

2. The processing method of the fiberglass protective layer for steel pipes as described in claim 1, characterized in that: In step (2), the steel pipe body is heated to 210℃-240℃ using a medium-frequency heating method.

3. The processing method for the fiberglass protective layer of steel pipe as described in claim 2, characterized in that: In step (2), plasma surface polarization is performed online immediately after the 3PE coating is formed.

4. The processing method of the fiberglass protective layer for steel pipes as described in claim 1, characterized in that: In step (3), the prepreg tape feeding device includes two or more feeding chucks, and each feeding chuck alternately feeds and winds the tape.

5. The processing method of the fiberglass protective layer for steel pipes as described in claim 4, characterized in that: The prepreg tape feeding device also includes a pressure roller to ensure that the prepreg tape is under certain pressure after being wound on the steel pipe, so that the prepreg tape is tightly attached to the surface of the anti-corrosion layer.

6. The processing method of the fiberglass protective layer for steel pipes as described in claim 4, characterized in that: The prepreg tape is a combination of epoxy elastomer and fiberglass cloth.

7. The processing method of the fiberglass protective layer for steel pipes as described in claim 4, characterized in that: When the prepreg tape is wound, the outer surface temperature of the steel pipe containing the anti-corrosion layer is 200℃-240℃.

8. The processing method of the fiberglass protective layer for steel pipes as described in claim 4, characterized in that: In step (5), the time interval from the completion of winding the thermosetting epoxy fiberglass prepreg tape to before cooling is 1-1.5 minutes to ensure that the prepreg tape and the anti-corrosion layer react fully.

9. The processing method of the fiberglass protective layer for steel pipes as described in claim 4, characterized in that: In step (5), the cooling is performed using a spray-type water cooling system.

10. The processing method of the fiberglass protective layer for steel pipes as described in claim 1, characterized in that: It also includes a conveyor belt for conveying steel pipes, the conveyor belt being composed of several conveyor rollers, wherein some conveyor rollers maintain the steel pipe's rotation around its axis by rotating on their own, and some conveyor rollers maintain the steel pipe's linear movement along its own axis by rotating on their own.