SU143227A1 - Discharge head of screw machines for the manufacture of pipes from thermoplastics - Google Patents

Description

Known screw heads of machines for the manufacture of pipes from thermoplastics by means of extrusion are known, provided with a guide, a sleeve and a matrix, forming an annular gap with the mandrel. However, such HEADS are not suitable for making double-layer pipes.

The proposed head for receiving double-layer pipes is made in the form of a body attached by two inlet nipples to two screw-machines. In this case, the concentrators are fixed concentrically, and the bushing, and the matrix forms an additional working annular gap with the head body. To heat the walls of the inner thermoplastic tube with compressed air or. gas, blowing it during welding, the mandrel can be made hollow and rigidly fixed to the thread in a radially movable cover of the case. An electric heating element can be placed inside the mandrel, and a tube with a tube for supplying compressed air or gas can be screwed into the lower, cylindrical part of the mandrel, the tube should pass inside the electric heating element, the upper end of which is fixed in the cap of the mandrel.

 FIG. 1 shows a head; in fig. 2 — nozzle for calibrating molded thermoplastic pipes.

The outlet head of screw machines for thermoplastic pipes made by extrusion consists of a casing / with two inlet nipples 2 and 5 for attaching concentric guide bushes 4, 5, 6, and 7 of a hollow mandrel 8, matrix J b 143327- to two machines.

9, regulating the mouthpiece 10, radially movable bolt // and cover / mandrel 15. A calibrating head 13 is attached to the head.

The thermoplastic melt flows from the screw auger into channel 14, from which bn-passes into the annular gap 5 between the housing V and the matrix I, which is the outer pipe 16 melting from the melt 16. From another screw machine, the melt of the second thermoplastic is fed into channel 17, and from it to the annular gap 18 between the matrix 9 and the mandrel 8, forming the inner tube 19. The side 20 of the guide sleeve 4 does not allow the thermoplastic from the canal 17 to get into the gap 15, and the bead 21 of the sleeve 5 does not allow the thermoplastic channel 14 to the gap 18. The sleeve 6 serves to separate the flows of both thermoplastics, and the sleeve 7 restricts the flow of thermoplastic material from the channel 17. The concentricity of the gap 15 is provided by moving the sleeve 10 when using screws 22, s the concentricity of the gap 18 is moved by the mandrel 8 together with the cover T1 by means of screws 23.

After exiting the head, the pipes 16 and 19 enter the brass nozzle 13, which has inside the fluoroplastic lining 24, which reduces friction and fuse protection: the first thermoplastic from sticking to the metal. The inner tube 19 is put on the stopper 25, covered with the fluoroplastic sleeve 26 and having an opening 27. The sleeve is held by a chain 28. In the cavity 29 of the pipe 19 through the tube 30, inside the darp 5 and fixed in the cap 12 and in the threaded stopper 31, compressed air is supplied or gas heated electrically. by element 32 and inflating pipe 19, thanks to which it is strongly welded to circumferential pipe J6. A plug 33, connected by a chain 34 with a plug 25, closes the cavity 29 of the pipe J9.

The finished double-layer pipe is cooled with water, continuously flowing into the bath 35, moved by the suction device using a device, cut into pieces of the required length or reeled onto the drum.

The described head allows to obtain pipes made from a combination of two thermoplastics having different properties, the inner layer of pipes directly contacting with the liquid or gas transported through the pipe, and the outer layer of more material material prevents the inner from aging and provides the necessary strength pipe walls.

Subject and purpose of (E &

Claims (2)

1. The screw discharge head for making pipes of thermoplastic materials by extrusion is equipped with a guide sleeve and a matrix forming an annular gap with the mandrel, characterized in that, in order to obtain double-layer pipes, it is made in the form of a cornus attached by two input fittings to two screw maschins, in which the guide bushings are concentrically fixed, and the matrix forms with it an additional working annular gap. 2. The head according to claim 1, characterized in that, in order to heat the steppes of the inner thermoplastic tube, they are compressed with air or gas m., Which inflates it during welding, the mandrel is hollow and rigidly fixed to the thread in the radially movable cornus cover, inside the mandrel an electric heating element, and in the lower, cylindrical, part of the mandrel, a plug with a tube is screwed to supply air or gas flowing inside the electric heating element, the upper end of which is fixed in the cap of the mandrel. /four 2Z 9 830 HW FIG. /