SU1366420A1 - Method of welding thermoplastic tubes - Google Patents

Abstract

The invention relates to a technique of thermoplastic welding and can be used in agricultural melioration, construction, communication industry, mechanical engineering, in particular, in welding of polyethylene pipes for water supply of agricultural objects. The aim of the invention is to simplify the process of preparing pipes for welding and sealing the seam. Before welding, an edge is removed at one of the pipes to be joined at an angle of 10-32 ° C. in the direction from the outer pipe to the inner pipe, then the inner wall of the other connected pipe at 800-950 ° C for 60-70 seconds from the pipe end, at a distance equal to the barb length, is heated by the flame of the burner for no more than 1 from the processed part of one pipe into the melted part of another pipe. Cool the compound in air without a load. 2 Il, 2 tab. (L

Description

The invention relates to thermoplastic welding and can be used in agricultural amelioration, construction, communications industry, mechanical engineering, in particular when welding polyethylene pipes for water supply of agricultural objects.

The purpose of the invention is to simplify the process of preparing pipes for welding and increase the tightness of the seam.

Fig. 1 shows a schematic of pipe processing with a whisker in Fig. 2, a scheme for heating and connecting pipes.

The welding method is as follows.

Pipes 3 and 2 made of polyethylene, PVP or PNI, having a length of 8 m each are placed in the center (its device, in which one of the clamps is movable, the end part of the pipe 1 is ground at an angle of 10-12 °, t, e, on the whole pipe wall thickness (Fig.). This part of the pipe is placed in a movable clamp. The end of another pipe 2 connected to the first one is clamped in a stationary clamp centered, its devices are inserted into the pipe with an open flame, having the flame outlet of the divider (Fig. 2), for 1-1.2 min. Then, in 0.5-1 seconds, the heater is removed and instantaneous The pipes 1 and 2 are melted and ground on the surfaces by inserting the second surface into the first surface. The connection is cooled in air without a load. The inner surface of the pipe 2 placed in the fixed clamp of the centering device is melted from the edge along the length of the pipe At the same time, the heater is not in contact with the polymer and eliminates sticking of thermoplastic to it. Melting the inner surface of one of the pipes to be joined by a burner flame with a temperature of 800–950 ° C allows for lko one of the weldable surface, to reduce the time and reliably welding the entire circumference osuschest vit contact with the surface of the other pipe.

Flame temperature is suggested for high density and small diameter polyethylene; 950 ° С - for large-diameter pipes of low density polyethylene (with a diameter greater than 50 mm and a thickness of 5.4 mm or more); 850 With - for PVP (high polyethylene

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0

density), starting with a pipe diameter of 25 mm or more; 900 ° C - for PNI pipes (low density polyethylene), whose diameter is 20-50 mm, at 800 ° C, the temperature gives unstable results of the reflow on the entire processed part of the pipe. Temperatures above 950 ° C are undesirable, since the surface of the thermoplastic cracks, becomes charred, and the material begins to flow, as a result of which the welding method is not implemented. The pipe melting time is taken from the calculation that for a low-density thermoplastic polymer, regardless of the thickness and diameter of the pipes, contact with the heating source is sufficient for 70 s, and for high-density thermoplastics 60 s, since a time longer than 70 s leads to overheating of the material, and less than 60 s is not enough to ensure a strong connection when the usa is inserted due to the low mobility of the structural elements of the melted surface, and the low adhesive strength of the surfaces.

The bevel angle of one of the pipes 10-12. With a bevel angle of less than 10, the mustache is easily deformed when another pipe is inserted into the melted part, and more than 12 ° bevel angle is undesirable because the strength characteristics of the joint deteriorate (a weld bead forms and the joints are reduced)

Table 1 shows the results of testing the method of welding polyethylene 0 new pipes from PNP,

With increasing thickness and diameter

five

0

five

pipes (bevel angle is increased from up to 12 °,

ten

Table 2 shows the dependence of the pipe welding mode on the thermoplastic material.

The proposed method shortens the welding time by a factor of 5–15 compared with the known thickness of the tube, greatly simplifies the process of preparing pipes for welding, increases the weld tightness by a factor of 2-3,

invention formula

The method of welding pipes from thermoplastics to the socket, including the removal at an angle of an edge from the end wall of one

313664204

pipes and heating the inner wall of the con- from the outer wall of the pipe to the inner,

The heating of the inner wall of the pipe is performed by the flame of the burner of the other pipe’s burner with the subsequent insertion of one pipe into another for no more than one second and cooling of the joint, different to TeMj, in order to simplify the process of preparing the pipes for welding and poke the joint tightness, removing the edge carried out on the mustache at an angle of 10-12 °

800–950 ° C from the end of the pipe for a length equal to the length of the whisker for 60–70 s, and the introduction of the pipe is carried out by inserting its end, processed into the melted surface of another pipe.

800–950 ° C from the end of the pipe for a length equal to the length of the whisker for 60–70 s, and the introduction of the pipe is carried out by inserting the end of the pipe into the melted surface of the other pipe.

The known method 3.0 80-87 0.18-0.2

4.7 85-90 0.19-0.22 5.2 / 0-100. 0.20-0.31

8.1 81-94 0.195-0.31 The proposed method

the way

45 chamfer

45 tall

45 1-2 mm

220-250

Table 1

Scapeing: welding, welding often leads to the formation of a septum inside the tubes of the bead in the seam and insufficient tightness due to local failure.

table 2

45

Continued table. 2

Claims (1)

Claim A method of welding pipes from thermoplastics into a socket, including the removal of an edge at an angle from the end wall of one 1366420 4 pipes and heating the inner wall of the end of the other pipe with the subsequent introduction of one pipe into another for no more than one second and cooling the connection, characterized in that, in order to simplify the process of preparing the pipes for welding and increase the tightness of the weld, the edges are removed by at an angle of 10-12 ° from the outer wall of the pipe to the inner one and heating of the inner wall of the pipe is carried out with a burner flame at a temperature of 800-950 ° C from the end of the pipe for a length equal to the length of the mustache for 60-70 s, and the introduction of the pipe is carried out by introducing it end oh works on the condition, in the reflow surface of another tube. Table 1 Pipe diameter mm Pipe wall thickness, mm Test methods Note Tensile stretch, MPa Tightness, MPa Known method 63 s oh 80-87 0.18-0.2 Bonding, welding often leads to the formation of inside 63 4.7 85-90 0.19-0.22 pipe septum from the roller in the seam and insufficient germ 110 5.2 70-100. 0.20-0.31 due to local lack of fusion BY 8.1 81-94 Proposed 0.195-0.31 the way * 63 3.0 170-182 0.40-0.45 The mustache is embedded in plastic part of another surface and 63 4.7 181-220 0.80-0.9 hermetically connects the contact point, the sharp 110 5.2 186-230 0.9-0.98 the section in the seam, its strength is equal to the strength of the base- BY 8.1 200-230 0.7-1.0 material table 2 Type of pipe material Pipe diameter mm Pipe wall thickness mm □ melting temperature of the pipe, ° C Pipe bevel angle, degrees Reflow time, min The time interval for removing the heating, power and pairing pipes, s 1 2 3 4 5 6 7 Known method PVP (polyethylene 10 2.0 220-250 45 fas ka 4-5 1-2 juice raft 12 2.0 220-250 45 high 4-5 1-2 nosti) that 20 2.0 220-250 45 1-2 mm 4-5 1-2 32 2.9 220-250 45 8-12 1-2 .5 Advance 2 --- _π ----- gp 5 ΙΖ 40 3.2 220-250 45 8-12 1 ”2 63 5.7 220-250 45 15-30 1-2 BY 6.2 220-250 45 15-30 1-2 PNP (poly 10 2.0 260-290 45 3-6 ethylene low which raft 20 2.0 260-290 45 3-6 nosti) 32 2.7 260-290 45 4-8 fifty 5,4- 260-290 45 5-10 63 4.7 260-290 45 5-10 110 5.2 260-290 45 5-10 110 8.1 260-290 45 8-15 The proposed method PVP 10 2.0 800 10 1,0 0.5 12 2.0 800 10 1,0 0.5 16 2.0 800 10 1,0 0.5 20 2.0 800 10 1,0 0.5 20 2.0 800 10 1,0 0.5 25 2,3 850 10 1,0 1,0 32 2.9 850 10 1,0 1,0 40 3.2 850 eleven 1,2 1,0 63 5.7 850 and 1,2 1,0 110 6.2 850 12 ¹ 1,2 1,0 PNP 10 2.0 900 10 1,2 0.5 20 2.0 900 10 1,2 0.5 32 2.7 900 10 1.2 0.5 fifty 5,4 950 10-11 1,2 1,0 63 4.7 950 and 1,2 1,0 110 5.2 950 12 1,2 1,0 110 8.1 950 12 1,2 1,0