GB2147521A

GB2147521A - Fluff filtering device of a drying and/or fixing machine

Info

Publication number: GB2147521A
Application number: GB08425390A
Authority: GB
Inventors: Franz-Josef Gierse; Heinrich Hermanns; Werner Hermes; Gerhard Lupnitz; Manfred Pabst; Heribert Schlicht
Original assignee: A Monforts GmbH and Co
Current assignee: A Monforts GmbH and Co
Priority date: 1983-10-06
Filing date: 1984-10-08
Publication date: 1985-05-15
Also published as: JPS6096882A; IT1196269B; GB8425390D0; FR2553117A1; IT8422858A1; IT8422858A0; DE3336332A1

Abstract

In order to be able to clean a fluff filtering device of a drying and/or fixing machine with a heated circulating air stream for processing a textile fabric web (1) and with a horizontal filter screen without interrupting production and without the possibility of the units to be protected being contaminated during the cleaning process, a continuous screening band (18) is provided which is guided at least over one roller (17) inside the machine and at least over one roller (16) outside the machine. <IMAGE>

Description

SPECIFICATION Fluff filtering device of a drying and/or fixing machine The invention relates to a fluff filtering device in a drying and/or fixing machine for the treatment of a textile fabric web with a heated circulating gas stream (e.g. heated air), the device comprising a filter screen disposed approximately horizontally in its operating position in order to prevent the ingress of fluff or similar deposits into a heat exchanger, combustion chamber, fan, or other unit in the machine. The machine is preferably a facing or smoothing drying or fixing machine, such as a stenter frame, a screen belt drier, a hotflue, or the like. The term "circulating air stream used below embraces any process gas used in machines of the type mentioned.

Directions parallel and transverse to the conveying direction of the fabric web are defined as the longitudinal and transverse direction of the machine.

In the case of machines, such as stenter frames, provided for the continuous drying and/or fixing of textile fabric webs, with a gaseous processing medium blown from nozzles preferably onto both sides of the fabric web, access to the internal parts of the machine becomes increasingly difficult as the design becomes more compact. This situation is particularly disadvantageous when cleaning the interior of the machine, which is necessary as a rule.In order to prevent fluff, threads, and the like, which drop off the fabric arriving more or less untreated in the processing machine, from reaching the sensitive machine units, for example the combustion chamber, the heat exchanger, or the circulating fan, and from leading to contamination or even the risk of fire there, filter screens are arranged in the circulating air stream - preferably in the return flow arriving from the fabric web before the said return flow comes into contact with the sensitive units disposed downstream.

As the filter screens catch fluff and similar deposits in accordance with their purpose, they form an increasingly substantial flow resistance to the circulated gas inside the machine. In order to economize on the cost of shutting down the machine for cleaning the screens, filter screens have been arranged in horizontal tracks in such a way that they have to be withdrawn laterally from the interior in the horizontal direction through slots provided in the machine wall without interrupting production, and cleaned outside the machine or exchanged for replacement screens. This cleaning or replacement must be carried out very quickly in order to keep to a minimum the penetration of fluff or simular deposits in the meantime into the units of the machine to be protected.

What is desired is a protective device for preventing the ingress of deposits into a heat exchanger, combustion chamber, fan, or similar units in the interior of the machine, which will permit cleaning of the filter screen while the machine is running, without interrupting production, and in which there is no risk of deposits to be filtered off penetrating during cleaning into the parts of the machine to be protected.

The present invention provides a fluff filter ing device in a drying and/or fixing machine for the treatment of a textile fabric web with a circulating gas stream, the device comprising a filter stream disposed approximately horizontally in the path of the circulating gas stream, in which the filter screen is in the form of a continuous screening band guided over rollers in the longitudinal or transverse direction of the machine, at least one roller guiding the screening band being disposed inside the machine and at least one roller guiding the screening band being disposed outside the machine.

By virtue of the invention it is made possible for the upper strand of the screening band to be drawn directly from the interior of the machine through a slot to the outside for cleaning there. In this way contamination caught on the screen passes out from the outside. Outside the machine the screen may have associated with it a cleaning apparatus whose cleaning capacity is preferably to be designed according to quality and quantity in such a way that continuous driving of the screening band rollers is made possible and consequently the flow resistance formed by the filter screen may be kept relatively constant.A particular advantage of continuous screening band cleaning is that only a slight quantity of deposits is to be conveyed out through the slot provided in the wall of the machine and consequently the slot can be kept relatively narrow, in such a way that it lets through the lower and upper band strand at the same time.

In principle the screening band can be arranged so as to be movable in the longitudinal or in the transverse direction of the machine. In the first case it can move in the conveying direction or opposite the conveying direction. In addition, a division into two band halves with motion in the inlet area opposite the conveying direction and in the outlet area in the conveying direction can be advantageous. On account of the shorter paths, however, motion transverse to the conveying of the fabric web is preferred.

The invention will be described further, by way of example only, in its application to a single layer stenter or stenter frame are explained with reference to the accompanying drawing in which a vertical section transversely to the longitudinal direction or a stenter frame is illustrated diagrammatically.

The fabric web 1 to be processed, held by chains 2 and 3 at the longitudinal edges, is fed through between nozzle casings 4 and 5 in the direction perpendicular to the plane of the drawing, and is then processed from above and below with the gas (in particular heated air) supplied by a fan 7 in the direction of arrow 6. The gas flowing back from the fabric web 1 in the direction of arrow 8 is at least largely sucked back again by the fan 7 and is once again blown back in circulation onto the fabric web 1. If the process gas is to be heated, as in the illustrated embodiment, it is guided on its path from the fabric web 1 towards the fan 7 through a heat exchanger 9 or through a combustion chamber 10, for example with direct gas heating means 11.

Since fluff, threads, and the like can drop from the fabric web 1 during its treatment with the process gas, a filter screen is inserted in the return flow in the direction of arrow 8.

In order to permit cleaning of this filter screen during operation, i.e. without opening a door 12 in the cover 13 of the machine, an arrangement has hitherto been made such that the filter screen, guided in lateral rails, could be withdrawn in the horizontal direction 15 from the interior of the machine through a slot 14 in the housing 13 and replaced or cleaned. In this connexion, one disadvantage was that the machine units 9, 10, or 1 1 arranged downstream of the operating position of the screen in the air stream 8 were unprotected during changing of the filter screen.

In order to overcome the difficulties described above, the present stenter frame comprises a continuous screening band 18 which replaces the fixed filter screen and which is guided over rollers 16 and 17 transversely to the conveying direction of the fabric web. The screening band 18 is preferably provided with a drive (not shown) acting on its roller 16 disposed outside the machine. In addition, optional guide rollers 20 are provided. Finally, it is advantageous to provide the slot 14 with a type of labyrinth seal 21 which substantially eliminates air exchange between the interior and the exterior, in particular when the screening band 18 is stationary, but which where possible does not scrape off deposits lying on the band while the screening band 16 is being moved in the direction of arrow 15 for cleaning.

If, during the operation of the stenter frame, contaminated air flows in the directon of arrow 8 through the screening band 18, deposits are filtered out at that point. If the deposits have reached a certain level, then, in particular after partial opening of the labyrinth seal 21, the upper strand of the screening band 18 is moved outwards in the direction of arrow 1 S, for example by actuation of the drive acting on the roller 16, in such a way that the deposits are removed from the interior of the machine. The screening band can be cleaned by brushing, suction, or the like by suitable cleaning apparatus (not shown) outside the machine. Cleaning can also be carried out continuously in the manner described.

Continuous cleaning and corresponding movement of the screening band in the direction of arrow 15 has the advantage that the flow resistance of the filter remains substantially constantly low during the operation of the machine.

Claims

1. A fluff filtering device in a drying and/ or fixing machine for the treatment of a textile fabric web with a circulating gas stream, the device comprising a filter screen disposed approximately horizontally in the path of the circulating gas stream, in which the filter screen is in the form of a continuous screening band guided over rollers in the longitudinal or transverse direction of the machine, at least one roller guiding the screening band being disposed inside the machine and at least one roller guiding the screening band being disposed outside the machine.

2. A device as claimed in claim 1, in which the screening band is guided between the outside roller and the interior of the machine through a slot receiving upper and lower strands of the band.

3. A device as claimed in claim 1 or 2, including cleaning apparatus associated with the screening band outside the machine.

4. A fluff filtering device substantially as described with reference to, and as shown in, the accompanying drawing.