DE20309664U1 - Hot molten plastic distributed to heated holding tanks via pipes surrounded by cavity mantle pipe filled with hot fluid medium - Google Patents

Abstract

A supply of molten plastic is maintained to heated holding tanks (4) via a main feed (2a) pipe with e.g. branch pipes (2b, c). The main feed pipe and branch (2b) pipes (2c) are separated by a cavity from a surrounding outer pipe. The cavity is filled with a hot fluid medium. The branch pipes (2c) are surrounded by a flexible cavity sleeve (3c). The flexible branch pipe sleeve is a corrugated hose.

Description

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Zimmer AG 12.06.2003

Borsigallee 1
60388 Frankfurt

Case No.: 20030001

Product pipeline for molten, liquid plastics Description

The invention relates to the structural design of the product feed of a heating box which is used in spinning mills for the production of synthetic filaments and fibres, such as polyester or polyamide.

In spinning mills, heating boxes are used to produce filaments and fibers. Pipes are used to transport hot liquid plastics to a pump and then to a nozzle system. The nozzles have a large number of holes through which the melt is extruded into filaments or fibers. In order to achieve uniform thread quality, the melt-carrying components must be tempered in such a way that the polymer melt has as uniform a temperature as possible over the entire product path. For this purpose, the heating box and the product pipeline leading to the heating box are heated. The product pipeline usually consists of an inner pipeline through which the liquid plastic flows. This inner pipeline is surrounded by a jacket pipe through which a heat transfer medium flows and washes around the inner pipeline. Hot steam or a heated liquid, for example, can serve as a heat transfer medium. If several heating boxes are arranged next to each other and are to remain in their position in both the heated and unheated operating state, a product pipeline is required that can compensate for the thermal expansion that occurs.

For this purpose, the inner pipe and the jacket pipe were previously laid "softly", or the jacket pipes were attached to the heating boxes using compensators.

Another variant is described in JP-A-2002227026. The product pipeline branches here using "deer antlers", e.g. in the case of four heating boxes shown and connected to one another.

The disadvantages of the current state of the art are the space requirements and the costs for the product piping, especially when several heating boxes with large dimensions have to be connected.

Based on this prior art, the invention is based on the object of creating a simple and inexpensive product pipeline for liquid plastics which has sufficient elasticity to compensate for thermal expansion.

This object is achieved according to the invention according to the characterizing features of patent claim 1.

The invention is explained by way of example with reference to Fig. 1.

Fig. 1 shows a schematic representation of a product pipeline with three heating boxes. The product pipeline is the combination of an inner pipeline with a surrounding jacket pipe. The inner pipeline consists of the inflow pipe (2a), the distributor piece (2b) and the connection pipe (2c). The jacket pipe consists of the inflow jacket pipe (3a), the distributor jacket pipe (3b) and the flexible jacket pipe (3c)
Liquid hot plastic (1) is led from a storage container (not shown) via the inner pipe to three heating boxes (4a, 4b, 4c).

A heating box essentially consists of pipes, a pump and a nozzle system for producing synthetic fibers and filaments. The heating box is tempered internally and is insulated from the outside. The temperature can be controlled electrically, inductively, with circulating heat transfer fluid or hot steam.
The inlet pipe (2a), distributor piece (2b) and connecting pipes (2c) are surrounded by a jacket pipe (3a, 3b, 3c) in which a heat transfer fluid or hot steam circulates, flushing around and tempering the inner pipes (2a, 2b, 2c). The connecting pipes (2c) to the heating boxes (4a, 4b, 4c) are laid "softly" so that a defined mobility is given when the heating boxes (4a, 4b, 4c) are stationary and the inner pipes (2a, 2b, 2c) are thermally expanded. Since, according to the state of the art, all jacket pipes (3a, 3b, 3c) and in particular the jacket pipe (3c) between the distributor jacket pipe (3b) and the heating box (4) are made of a rigid material with soft pipe laying (deer antlers) or flexible fastening by e.g. a compensator on the heating box (4), there are large tensions from the pipe system, since two more or less rigid pipe systems act simultaneously on the connection point in the heating box. By arranging a flexible jacket pipe (3c) between the distributor jacket pipe (3b) and

The thermal stresses can be better compensated for in the heating boxes (4a, 4b, 4c) because the flexible jacket pipe (3c) has greater mobility in all directions. A flexible jacket pipe (3c) is a pipe that simultaneously allows changes in length and angle over essentially the entire length of the pipeline (3b). This is also the key difference to so-called "soft" connections of essentially rigid pipes or to compensators. The flexible jacket pipes (3c) are made of temperature-resistant metal, such as steel, aluminum, stainless steel or plastics. Corrugated hoses are preferably used for this purpose. These corrugated hoses are particularly preferably made of stainless steel. The use of flexible jacket pipes (3c) between the distributor jacket pipe (3b) and the heating box (4) is useful for at least two or more heating boxes (4a, 4b ...4n).

Claims (2)

1. Product pipeline for supplying at least two heating boxes with hot liquid plastic, with an inner pipeline through which the hot liquid plastic is conducted, and a jacket pipe surrounding the inner pipeline, a heat transfer medium flowing between the inner pipeline and the jacket pipe, the inner pipeline consisting of an inlet pipe ( 2 a), a distributor piece ( 2 b) and at least two connecting pipes ( 2 c), characterized in that each connecting pipe ( 2 c) is surrounded by a flexible jacket pipe ( 3 c). 2. Product pipeline according to claim 1, characterized in that a corrugated hose is used as the flexible jacket pipe ( 3 c).