DE7619647U1 - Extruder for applying thermoformable plastic compounds to an electrical conductor - Google Patents

Description

114

ι ilia

SIEMENS AKTIENGESELLSCHAFT Our mark

Berlin and Munich VP / 76 G 451O FRG

Extruder for applying thermoformable plastic compounds to an ele ctrisc hen conductor .

The innovation relates to an extruder for applying thermoformable plastic compounds to an electrical conductor as Isolation with a cross-head comprising a mouthpiece and a mandrel guiding the conductor, with the melt flow passing through the mandrel holder flows around and emerges from the annular gap delimited by the mandrel and mouthpiece.

The mandrel holder required by this construction, the one for cross-spray heads must be flowed around is an obstacle for the extrusion of cable insulation, jackets and hoses Melt flow is. As a rule, known devices this type of melt flow with a so-called heart wrapper divided into two substreams, and the substreams are merged again after each of the substreams is divided into half of the Thorn circumference is distributed. At the seam lines of the partial flows, the extrudate has undesirably different properties than in other areas. Seen across the extruder cross-section, this causes a number of errors, such as an eccentric one Insulation when using foamable insulation material, Foaming differences in cross-section, training of flowing boundary lines at the point of contact between the two partial flows and, finally, generally an inhomogeneity of the insulation material.

Size 22 Bek / 06/16/76

7619647 12/1/77 '

- 2 - VPA 76 G 4510 BRD

The innovation is based on the task of an extruder transverse die head to be trained so that in its inflow area a complete symmetry of the melt flow an extremely good mixing causes and that the formation of flow lines or boundary lines of the two melt partial flows is avoided. Besides that a mixing and homogenization of the melt should be achieved immediately before the shaping process when the melt is brought together. '

This object is achieved according to the innovation the fact that the {inlet openings is assigned to the melt flow in the mandrel holder Depending ι a melt pump. The two melt pumps ensure a completely even mixing of the melt and thus the equality at the entry points in the mandrel holder. Gear pumps are preferably used as melt pumps.

The innovation is based on the embodiment shown in the drawing explained in detail.

The single figure shows a schematic longitudinal section of the front part of an extruder with the cross-extrusion head assigned to it.

The extruder 10, which is constructed in a known manner from an extruder cylinder 11 and an extruder screw 12, stands over an extrusion head housing 14 with a cross-head 13 in connection, which essentially consists of a sleeve 15 and a mandrel holder guided therein 16 consists. At the entry point of the melt flow into the cross-head, a cutting edge 18 divides the melt into two Channels 31, which each lead to a gear pump 32. The gear pumps cause the two to then pass through the inlet openings 34 the mandrel holder 16 supplied partial flows of the melt are necessarily the same. In addition, the melt flow intensively mixed again by the gear pumps.

1 figure

2 claims for protection

7619647 12/01/77

Claims (2)

; > O J ti Λ Ι a ott JO G 76 19 647.9 VPA 76 G 4510 BRD New protection claims 1. Extruder for applying thermoformable plastic compounds
an electrical conductor as insulation with a spray head comprising a mouthpiece and a mandrel guiding the conductor, the melt flow flowing around the mandrel holder and emerging from the annular gap delimited by the mandrel and mouthpiece, characterized in that . that in front of the inlet openings (34) for the
Melt flow in the mandrel holder (16) is arranged in each case a melt pump (32). 2. Extruder according to claim 1, characterized in that the
Melt pumps (32) are designed as gear pumps. 7619647 12/01/77