SU1680557A1 - Method of plastic pipes welding - Google Patents

Abstract

This invention relates to a technique for welding plastic pipes. The goal is to improve the quality of a welded joint. To do this, according to the method of welding plastic pipes, before heating the weld zone, a metal ring is placed on the outer surface of the coupling and deformed it and the coupling before a technological tension is formed between the connecting surfaces of the pipes and the coupling. The deformation is carried out in an electric inductor with a magnetic-pulsed field energy of 0.3-10-0.8-10 J / m3 at 20-150 ° C. 4 ill., 2 tab.

Description

 The invention relates to a technique for welding plastics and can be used in welding plastic pipes.

The purpose of the invention is to improve the quality of the welded joint.

FIG. 1-3 illustrate the steps of the method; figure 4 - weld.

The method of welding plastic pipes is as follows.

The connected butted ends of the pipes 1 and 2 are wound around the heating element 3. Then, a plastic sleeve 4 is installed on them freely with a gap, on the outer surface of which they put a metal ring 5, for example, of aluminum alloy.

The pipes with a sleeve prepared in this way are inserted (Fig. 2) into an electric inductor 6 of a magnetic-pulse installation (Fig. 2). When a capacitor C battery is discharged onto an inductor (FIG. 3), the magnetic-pulsed field arising in the gap between the inductor 6 and the metal ring 5 deforms the ring and the coupling to

elimination of the gap between the coupling and the pipe and the formation of technological tension between them. The energy of the magnetic impulse field is in the range of 0.3–0.8 J / m3.

The temperature of the magnetic impulse deformation is chosen from 20 to 150 ° C depending on the type of polymer and the initial gap between the pipe and the coupling, which determines the necessary plastic deformation of the coupling to eliminate this gap (see Table 1).

When the electric current passes through the heating element 3, it heats up, brings the polymer in the contact state to the polymer in the zone of contact between the pipe and the coupling. The heater is turned off during the formation of an influx of 7 (FIG. 4) along the ends of the coupling. The formed compound is fixed by cooling.

The gap between the pipe and the coupling, depending on the outer diameters of the pipe and coupling (It) and their thickness (t) is given in table 2.

PRI me R 1. Welding with a coupling with an embedded heating element,

cl

with

about.

00 Oh

sl sl 1

made of nichrome wire with a diameter of 0.1 mm, pipes of type SL from PND TU 18599-83, with a diameter of 25 mm.

The coupling is made in the form of a segment of a pipe of larger diameter (32 mm) along the assortment of the same specification, while the gap between the pipe and the coupling can be a maximum of 1.85 mm and a minimum of 0.8 mm (Table 2). Coupling width 50 mm.

The ends of welded welded pipes 1 and 2 (FIG. 1) are wound with a heating element 3 (20 Ohm), and a sleeve C is placed on top with an aluminum alloy ring on the outer surface with a wall thickness of 1 mm and a width of 50 mm. Then the coupled pipes are inserted together with the coupling into the electric inductor 6 (Fig. 2) and at 20 ° C they discharge the capacitor bank with the stored energy of 0.3-109 J / m3 of the magnetic-pulse installation (MIU-20) onto the inductor (fig.Z), which creates a pressure of about 40 MPa. At the same time, the polyethylene from which the coupling is made, under the specified pressure, is plastically deformed and selects the gap between the pipe and the coupling, ensuring a tight fit of the welded surfaces between themselves and the heating element. The temperature rise to form a welded joint up to 180 ° C is carried out by applying a voltage of 110 V to the ends of the wire for 2 minutes. The end of welding is determined by the melt flow of polyethylene in the form of an influx of 7 along the end of the coupling (Fig. 4).

Example 2. Welding with a coupling with a mortgage heating element made of nichrome wire, PVC pipes of mark PVC-100 TU 6-19-231-83 type T with a diameter of 25 mm.

The coupling is made in the form of a pipe segment of a larger diameter (32 mm) in a range of the same specification, and the gap between the pipe and the coupling can be from 1.3 to 2.2 mm on one side.

The ends of the coupled pipes 1 and 2 (figure 1) are wound heating ele5

0

ment 3, and on top place a sleeve with an aluminum alloy ring on the outer surface with a wall thickness of 1 mm. To eliminate pipe deformation

a metal bar or pipe is inserted into the place of their connection as a support. The coupling is heated to 150 ° C, placed in the inductor 6 (Fig. 2) of the magnetic-pulse installation, and the discharge is performed

0 capacitor battery with stored energy 0,7-10 J / m per inductor. At the same time, the polyvinyl chloride from which the coupling is made, under pressure of the aluminum ring about 80 MPa, is plastically deformed. The gap between the pipe and the coupling is chosen to provide technological tension and a tight fit between the surfaces to be welded. The temperature rise to form a welded joint up to 200 ° C is carried out by applying a voltage of 120 V to the ends of the wire for 1.5 minutes. The end of welding is determined by the melt flow of polyvinyl chloride in the form of an influx of 7 along the end of the coupling

5 (Fig. 4). After cooling, the metal bar is removed from the pipe. Get a welded joint with a relative strength of up to 1.0.

Claims (1)

Claims The method of welding plastic pipes, including placing a heating element at the joined ends of pipes, installing a plastic sleeve on them, heating the welding zone by passing electric current through the heating element and cooling the welded joint, characterized in that, in order to improve the quality of the welded joint, Before heating the weld zone on the outer surface of the coupling, install a metal ring and deform it and the coupling to form a technological tension between the connected overhnost E pipes and couplings, wherein the deforming is carried out in an electric energy inductor mag0 five 0 five nitro pulsed field 0.3-10 - 0.8 J / m3 at a temperature of 20-150 ° C. Table 1 10U table 2 $ 005b & Ј006 XWVSAAXXXXV 1 v -UUUHACHAHHHHU  | KXXX 6 WW five- / 1 oh oh FIG. 2 FIG. four Fig.Z V