GB2299032A - Filter disc - Google Patents

Abstract

A filter disc comprises two outer gauze filter layers (11, 12), an intermediate gauze filter set (13) and an outlet ring (14) which bounds a central outlet bore. The two opposite end faces of the ring are each formed by a plurality of spaced surface portions (15) which are formed by parts projecting in alternation in direction towards the two faces. These parts bound outlet channels (16), which are present between the surface portions and which, by virtue of their mode of formation, have relatively large flow cross-sections to permit easier outflow of viscous fluids. The ring can be a pressed metal component.

Description

FILTER DISC The present invention relates to a filter disc.

A filter disc is installed in, for example, a continuously operating central filter unit which feeds polymeric melt to a plurality of spinning positions in the manufacture of filaments of polyester or polyamide and which filters out contamination from the melts. The melt is filtered and flows into a central bore of the disc from where it passes by way of pipe ducts to the spinning positions. The melt has a relatively high viscosity or is extremely viscous in flow. An outlet ring is disposed bvetween outer wire gauze filter layers of the disc. The internal diameter corresponds with bores in the layers, whilst the external diameter is significantly smaller than the external diameter of the layers. The ring is highly loaded, for example by 3000 kilograms.

In a known construction, the outlet channels are bores formed radially in the ring. The construction has the disadvantage that the bores are relatively small due to the small thickness of the exit ring and the drilling is difficult to perform. Moreover, due to the small diameter of each individual channel, the high viscous melt has a poor flow towards the centre, since the sum of the bore crosssections is only a fraction of the area of the lateral surface of the ring.

There is therefore a need for a filter disc in which an outlet ring thereof is able to acceDt high loading, is simple to manufacture and allows the melt to flow substantially better through outlet channels towards the centre.

According to the Dresent invention a filter disc is provided with a central bore and comprises two filter layers Droduced from a metal wire gauze, a drainage package produced from a metal wire gauze and a central outlet ring which bounds the bore and is Drovided with radially extending outlet channels, wherein the two end faces of the ring are divided into surface portions and the individual surface portions protrude in alternation in the direction of the oppositely disposed end face so that the surface portions disposed in mutual displacement relative to the outer end faces bound the outlet channels.

The outlet ring of the filter disc is preferably a shaped oart, which is normally pressed from metal, for example steel, by means of a suitable tool. The individual surface portions can also be regarded as segments. The outer end faces of the ring no longer represent a closed surface, but consist of several individual surface portions. The surfaces standing in mutual displacement to these outer end faces have the effect that lateral webs extend obliquely to the end faces. Thereby, a substantial degree of rigidity is achieved for the ring. Moreover, the channels are not unduly limited by the thickness of the ring, but can be substantially greater in crosssection than the radial bores in the known ring construction. The melt can thus flow substantially more easily towards the centre. An expensive drilling operation is avoided and the ring can be produced more economically.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is an elevation of a filter disc embodying the invention, in which a filter layer has been removed for the sake of clarity; and Fig. 2 is a sectional view of the disc in exploded illustration.

Referring now to the drawings there is shown a filter disc 10 which comprises two outer filter layers 11 and 12 each oroduced of a metal wire gauze, several central wire gauze layers 13, which for reasons of simplicity are shown as a unit, and an outlet ring 14.

The layers 13 are also oroduced from metal wire gauze and form a drainage package. The layers 11 to 13 are provided with bores into which the exit ring 14 is inserted to close them. As Figs. 1 and 2 show, the exit ring 14 is a shaped part. The two outer end faces of the ring are each formed, in the illustrated embodiment, by six individual surface portions 15 which are disposed at an angular spacing one from the other. At both sides, outlet channels 16 for the melt lie between the individual surface portions 15. These channels are bounded by surfaces which stand in mutual disDlacement relative to both the end faces or the individual surface portions 15 and thereby form lateral webs. The outer filter layers 11 and 12 consist of several individual layers, between which the ring 14 then lies. The outer rims of the filter layers 11 and 12 are strongly compressed and displaced in direction towards the centre so that they lie against one another. The middle layers 13 extend by their outer rims uD to this displacement. The connection is effected by, for examDle, plasma welding of the compressed rim zones of the outer filter layers 11 and 12. In the normal case, the filter fineness of the outer filter layers 11 and 12 is substantially smaller than the mesh width of the inner wire gauze layers 13, which have merely a drainage function.

Claims (7)

1. A filter disc provided with a central bore and comprising two outlying mesh filter elements, an intermediate mesh filter group and a central outlet ring bounding the bore and having substantially radially extending outlet channels, wherein the two end faces of the ring are each divided into individual surface portions and parts defining the surface portions Droject in alternation in the direction of the first end faces and bound the outlet channels.

2. A filter disc as claimed in claim 1, wherein the filter elements and filter group comprises metal gauze.

3. A filter disc as claimed in claim 1 or claim 2, comDrising a plurality of the outlet channels at each end face of the ring.

4. A filter disc as claimed in claim 3, comDrising six such outlet channels at each end face of the ring.

5. A filter disc as claimed in any one of the preceding claims, wherein the ring is a Dressed metal Dart.

6. A filter disc as claimed in claim 5, wherein the metal is steel.

7. A filter disc substantially as herebefore described with reference to the accompanying drawings.