CN100553931C - Production technology of the steel skeleton plastic clad pipe of band plastics termination and products thereof - Google Patents

Abstract

The invention discloses a production process and a product of a steel skeleton plastic composite pipe with a plastic end. The beneficial effect of the invention is that the problem that the steel skeleton plastic composite pipe is difficult to use hot-melt butt joint connection is solved by setting the injection molding end. The problem is that the steel skeleton plastic composite pipe with injection molding end provided by the present invention is connected by hot-melt butt joint connection, and the steel skeleton and the plastic end face connector are melted and connected as one, which completely solves the phenomenon of delamination and peeling off of the steel-plastic interface on the end face of the composite pipe. The reliability is greatly improved, and at the same time, it brings the advantages of low material consumption, easy manufacturing, low assembly cost, controllable welding pressure, little influence of human factors, and easy quality assurance.

Description

Production process and products of steel skeleton plastic composite pipe with plastic end

technical field

The invention relates to a forming process of a steel frame plastic composite pipe and its products, in particular to a production process of a steel frame plastic composite pipe with a plastic end and its product.

Background technique

Steel skeleton composite pipe is a new type of pipe emerging in China in recent years. It is widely used in many fields such as petroleum, chemical industry, construction, shipbuilding, communication, electric power and underground gas pipeline. It is the best product to replace traditional galvanized pipe at present. Known as the green environmental protection pipe.

At present, the connection methods for steel skeleton composite pipes at home and abroad are basically flange bolt connection and electric melting sleeve connection, but the above connection methods have the following defects, as follows:

① Flange connection

1. It cannot be used for buried piping systems; 2. The connecting fasteners used are metal parts, which are not corrosion-resistant; 3. The manufacturing cost is high; 4. It is relatively difficult to install.

②Electric fusion connection

1. It cannot be used for the connection of pipes and pumps, valves and other pipeline parts; 2. Due to the influence of various factors such as environment and process during installation, it is difficult to control the temperature and melt pressure in the welding zone; 3. Due to the existence of pipe fittings and pipe materials The large out-of-roundness causes a large fit gap between them, resulting in material running out during the welding process, local virtual welding and missing welding, and affecting the quality of the project; 4. The electric heating wire needs to be installed for the electric melting joint, and the structure is complex , the cost is high; 5. There is a gap on the welding surface of the electrofusion joint, causing "water channeling" and other phenomena.

With the improvement of the automation of hot-melt butt joint equipment, hot-melt butt joint, as a connection method between plastic (resin) pipes and plastic (resin) pipes, has matured in technology, and the hot-melt butt joint also has the advantages of saving materials and is easy to manufacture. , low assembly cost, controllable welding pressure, small influence of human factors, and easy quality assurance, etc. However, since the end face of the steel skeleton plastic composite pipe is a steel-plastic composite structure, it is impossible to directly use hot-melt butt joint connection to connect the steel skeleton composite pipe. difficulty. Therefore, how to produce a kind of steel frame composite pipe to adapt to the hot-melt butt joint has become a problem that everyone pays attention to at present.

In addition, aiming at the improvement of the connection method of the steel skeleton composite pipe, a variety of steel skeleton plastic composite pipe products have been developed.

Comparative document CN200310104507 discloses an injection-molded steel frame composite pipe, the plastic connecting body at the front end and the pipe body are only connected at the small end face of the steel frame composite pipe, and the connection surface is perpendicular to the pipe axis. This design has the following defects: firstly, the connection part is not stable enough, especially when the injection pressure and temperature are difficult to control during pipe production, the plastic connecting body and the pipe body are prone to detachment; secondly, this structure makes it difficult for the pipe to stretch and bend during use Due to the force, the installation layout of the pipes is greatly restricted. Again, the shapes of the two ends of the injection-molded steel frame composite pipes are different, so it is difficult to adapt to the current pipeline production of pipes, and the production efficiency is low.

The comparison document CN03237356 discloses a steel frame plastic composite pipe with socket and hot-melt welded joints. This structure has the following defects: 1. Heating wires and terminal posts need to be installed on the inner wall of the hole, which makes the production process complicated and the cost is still relatively high. High; ②Pipe connection stability is greatly affected by the environment. If there is a gap in the connection part (between the socket port and the socket port) during the pipe connection process, the air in the gap will expand during the heating process and easily enter the plastic of the connection part to form Air bubbles greatly affect the connection stability. ③ It is necessary to make the socket port and the socket port at the head and tail of the steel skeleton composite pipe respectively, and the cost is relatively high.

Contents of the invention

One of the objectives of the present invention is to provide a production process for steel skeleton composite pipes with plastic ends that can be directly connected by hot-melt butt joints.

Another object of the present invention is to provide a steel skeleton plastic composite pipe that can directly use butt joints for pipe connection with plastic ends.

In order to achieve the above-mentioned first object, the technical solution of the present invention is: a production process of a steel skeleton plastic composite pipe with a plastic end, which is characterized in that it includes the following steps:

a) Send the end of the steel skeleton plastic composite pipe into an oven, and heat the plastic layer at the end to a suitable temperature that can be welded with the plastic material of the plastic end;

b) Rapidly extend the end of the heated steel-frame plastic composite pipe into the injection mold for injection molding. The injection mold includes an injection molding outer mold sleeved on the steel-frame plastic composite pipe and coaxial with the steel-frame plastic composite pipe. The inner fixed mandrel in the injection molding outer mold, the injection molding outer mold is a Huff mold, the inner wall of which is provided with an annular inner concave cavity, the end of the steel skeleton plastic composite pipe is placed in the annular inner concave cavity, and its end surface A certain space is reserved with the end face of the annular inner concave mold cavity, and the end of the internal fixed mandrel penetrates into the space and abuts against the nozzle of the steel skeleton plastic composite pipe;

c) Keep the injection molding pressure state for cooling and setting;

The further setting is that there is a following step between the steps a and b: processing several annular grooves on the outer plastic wall at the end of the steel skeleton plastic composite pipe.

It is further provided that the depth of the annular groove is 0.5-1 mm.

In order to achieve the above-mentioned second object, the technical solution of the present invention is to include a steel skeleton and a plastic layer covering the inside and outside of the steel skeleton. Covered with a plastic end, the plastic end includes a welded joint at the front end and a side-attached part at the tail end, the welded joint and the side-attached part are integrally formed, and the welded joint is closely attached to the end surface of the steel skeleton plastic composite pipe Matching, the side sticking part is close to the side wall covering and fixing the outer plastic layer on the end part.

It is further provided that the connection between the side sticking part and the outer wall of the outer plastic layer at the end of the steel-framed plastic composite pipe is in the shape of a ring-shaped concave-convex surface interlaced.

A further setting is that the concave-convex surface is sawtooth-shaped. In this setting, the concave-convex surface may also be in the shape of a square wave.

The beneficial effects of the present invention are: the problem that the steel skeleton plastic composite pipe is difficult to use hot-melt butt joint connection is solved by setting the injection molding end, and the steel skeleton plastic composite pipe with injection molding end provided by the present invention is connected through the hot melt butt joint connection, The steel frame and the plastic end-face connector are melted and connected as one, which completely solves the phenomenon of delamination and peeling of the steel-plastic interface on the end face of the composite pipe, greatly improves reliability, and at the same time brings material saving, easy manufacturing, low assembly cost, and high welding pressure. Control, less influence of human factors, easier quality assurance and other advantages.

The present invention will be further introduced below in conjunction with the accompanying drawings.

Instructions attached

Fig. 1 process flow chart of the specific embodiment of the present invention

Fig. 2 turning schematic diagram of the specific embodiment of the present invention

Fig. 3 schematic diagram of end heating of the specific embodiment of the present invention

Fig. 4 injection molding schematic diagram of the specific embodiment of the present invention

Fig. 5 structural representation of product of the present invention

The hot-melt butt connection diagram of the product of the present invention in Fig. 6

Detailed ways

As shown in Figures 1-6, the specific embodiment of the present invention prepares a steel frame plastic composite pipe 1, which includes a steel frame 11 and a plastic layer 12 coated inside and outside the steel frame. Composite structure, the steel skeleton 11 can be in the form of perforated steel strips, steel wire mesh, etc., the inner and outer plastic layers can be made of plastic materials such as PE, PVC, and then the steel skeleton plastic composite pipe 1 is placed on the pipeline delivery frame 3 On the outer plastic layer 12 of the end of the steel frame plastic composite pipe, several annular grooves 15 are processed by the turning machine 2, preferably the depth of the annular groove is 0.5-1mm, and then passed through the pipeline transport frame 3 Send the end of the steel-frame plastic composite pipe 1 into the oven 4, heat the plastic layer 12 at the end to a suitable temperature that can be welded with the plastic material of the plastic end, and place the heated end of the steel-frame plastic composite pipe 1 Quickly put it into the injection mold for injection molding. The injection mold includes an injection molding outer mold 5 sleeved on the steel skeleton plastic composite pipe and an internal fixed mandrel 6 coaxially arranged in the injection molding outer mold 5 coaxially with the steel skeleton plastic composite pipe 1. The injection molding outer mold 5 is a Huff mold, and its inner wall is provided with an annular inner cavity, and the end of the turned steel skeleton plastic composite pipe is placed in the annular inner cavity, and its end surface is in contact with the annular inner cavity. There is a certain space reserved between the end faces of the cavity, and the end of the internal fixed mandrel 6 penetrates into the space and abuts against the nozzle of the steel frame plastic composite pipe, so that a fusion joint 131 is formed by injection molding at this space position, so that The remaining part of the annular inner concave mold cavity is injection-molded to form a side sticking part 132, and the connection between the side sticking part 132 and the outer wall of the outer plastic layer 12 at the end of the steel skeleton plastic composite pipe nozzle is an annular concave-convex surface 14. Staggered fit, the annular concave-convex surface 14 can be in the shape of sawtooth wave or square wave. In this embodiment, the annular concave-convex surface is preferably square wave-shaped. Keep the injection molding pressure state for cooling and shaping, and finally the product goes off the assembly line.

Claims (2)

1. A production process of a steel skeleton plastic composite pipe with a plastic end, is characterized in that: comprise the following steps: a) Send the end of the steel skeleton plastic composite pipe into an oven, and heat the plastic layer at the end to a suitable temperature that can be welded with the plastic material of the plastic end; b) Process several annular grooves on the outer plastic wall of the end of the steel skeleton plastic composite pipe; c) Rapidly extend the end of the heated steel-frame plastic composite pipe into the injection mold for injection molding. The injection mold includes an injection molding outer mold sleeved on the steel-frame plastic composite pipe and coaxial with the steel-frame plastic composite pipe. The inner fixed mandrel in the injection molding outer mold, the injection molding outer mold is a Huff mold, the inner wall of which is provided with an annular inner concave cavity, the end of the steel skeleton plastic composite pipe is placed in the annular inner concave cavity, and its end surface A certain space is reserved between the end surface of the annular inner concave mold cavity, and the end of the internal fixed mandrel penetrates into the space and abuts against the nozzle of the steel skeleton plastic composite pipe; d) Keep the injection pressure state for cooling and shaping. 2. The production process of the plastic end of the steel skeleton plastic composite pipe with plastic end according to claim 1, characterized in that: the depth of the annular groove is 0.5-1mm.

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