Gas separation – With gas flow effecting means
Reexamination Certificate
1999-08-09
2001-04-24
Smith, Duane (Department: 1724)
Gas separation
With gas flow effecting means
C055S476000, C055S484000, C015S352000
Reexamination Certificate
active
06221121
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a filter apparatus for use in cleaning a traveling airstream in association with the operation of a textile machine, especially an open-end rotor spinning machine.
Textile machines, especially textile machines operating according to the so-called open-end spinning process, usually comprise a vacuum system which is specific, i.e., dedicated, to the machine and provides the vacuum needed for the spinning process at the multiple open-end spinning stations of the machine.
As a rule, such vacuum systems comprise a vacuum source, e.g., a suction blower, a filter chamber connected upstream of the blower, and a suction conduit running the length of the machine and emptying into the filter chamber, to which conduit the individual open-end spinning units are connected via branch lines. In addition, in many of the known open-end rotor spinning machines a suction device for cleaning the soil conveyor belts of a mechanical soil removal device arranged below the spinning units is often connected to the filter chamber or to the suction conduit.
A filter element is located inside the filter chamber, usually transversely to the flow of suction air, to filter the incoming suction air which is typically contaminated with soil particles, e.g., dirt, debris, trash, foreign matter, and fibrous waste (fiber fluff, fly and remnants), etc., whereby the filter element retains the soil particles in the filter chamber.
However, these known devices have the disadvantage that the filter element becomes heavily clogged by the soil particles after a relatively short period of operation, which results in a distinct pressure drop in the vacuum system of the textile machine. Thus, since open-end spinning machines always require a minimum vacuum for proper performance of the production process, the filter elements must be cleaned at relatively short intervals of time in the known devices.
In order to lengthen these cleaning intervals, it has already been suggested that a filter element be arranged in the filter chamber in such a manner that the filter element is self-cleaning. Such a filter element is described, e.g., in German Patent Publication DE 42 29 552 A1 wherein the vacuum system of the textile machine comprises a filter chamber with two vertically standing filter elements arranged in an L-shape. A connection for a vacuum source is positioned approximately centrally in front of one of the two filter elements whereas a suction-conduit connection arranged in the cover of the filter chamber empties slightly offset to the side into the filter chamber. The flow conditions of the incoming suction airstream which are thusly developed in such an arrangement inside the filter chamber assure that at least the filter element arranged in front of the vacuum source is cleaned of adhering soil by the motion of the soil entrained in the airstream, especially fiber fluff, fly and remnants.
The known device thus requires a sufficient amount of such fibrous waste to keep the filter element clean and accordingly is primarily designed for textile bobbin winding machines in which yarn remnants always accumulate in rather large amounts as a rule. The known device is less suitable for open-end spinning machines since fibrous waste is rather low in these textile machines in relation to the relatively fine soil particles and other trash particles which are liberated during the sliver opening step in open-end spinning and must be removed.
SUMMARY OF THE INVENTION
In view of the above described state of the art, it is an object of the present invention to provide a filter apparatus with an improved filter element which will perform advantageously in a textile machine to filter fine particles of soil and trash with relatively low amounts of fibrous waste.
The invention achieves this objective by providing a novel form of filter apparatus for use in a vacuum system of a textile machine comprising a vacuum source and a suction conduit. Basically, the filter apparatus comprises a housing having a side wall and a bottom wall defining a filter chamber, a first connection device for connecting the housing to the vacuum source, a second connection device for connecting the housing to the suction conduit, and a filter disposed within the filter chamber for dividing the filter chamber into a dirty-air area and a clean-air area. According to the present invention, the filter comprises at least two filter elements including a relief element disposed in the filter chamber at a spacing from the side wall and relative to the first and second connection devices such that a flow of suction air therebetween travels between essentially parallel to and essentially an acute angle to the relief element, and a collector element disposed in the filter chamber at a spacing from the bottom wall and relative to the first and second connection devices such that a flow of suction air therebetween travels between essentially orthogonally to and essentially an obtuse angle to the collector element.
The design of the filter of the present invention and the special arrangement of the filter elements inside the filter chamber assure that the soil particles, which pass via the suction-conduit connection into the filter chamber and are for the most part quite fine, are deposited immediately on the collector element and remain thereon. That is, the relief element, along which the suction airstream initially flows almost parallel thereto, remains very largely free of soil particles. The orientation of the air flow to be almost tangential in the area of the relief element even causes soil particles which may adhere at first to the relief element too be separated from the relief element by the air flow, transported in the direction of the collector element and deposited thereon. Thus, this arrangement of the filter elements in accordance with the present invention has the effect of assuring flow conditions prevail in the area of the relief element over a long period of time under which conditions a flow component which is essentially tangential, i.e., parallel or at least substantially acute, relative to the relief element is distinctly greater than any flow component directed more orthogonally toward the filter element. The apparatus of the invention has distinct advantages compared to conventional filter apparatus both with respect to the degree of the pressure loss as well as with respect to the time at which the pressure drop begins.
The first connection device via which the filter housing is connected to a vacuum source, e.g., a suction blower, is preferably disposed in the bottom area of the filter housing. For example, the connection device may be fitted in the side wall of the filter housing, preferably at or just above the bottom wall of the housing. In this embodiment, the collector element is positioned at least partially above the first connection device for the vacuum source, preferably in approximately horizontal alignment and at a relatively distinct spacing from the bottom wall of the filter housing. In another embodiment, the first connection device may be integrated directly into the bottom wall of the filter housing.
In both embodiments, a certain pressure difference develops in the area above the bottom of the filter housing, i.e., in the clean-air area below the collector element, in comparison to the dirty-air area above the collector element. The impulse forces which prevail as a result assure that the fine soil particles located in the area of dirty air are reliably held fast on the collector element.
Preferably, the second connection device to the suction conduit is disposed in the upper area of the filter housing and fitted in the top wall, i.e., the cover, of the filter housing to be opposite and in facing relation to the collector element. The previously described arrangement for the first vacuum-source connection device in conjunction with this selected positioning of the second suction-conduit connection device in the upper area of the filter chamber results in a flow of suction
Schelter Detlef
Spitzer Michael
Hopkins Robert A.
Kennedy Covington Lobdell & Hickman L.L.P.
Smith Duane
W. Schlafhorst AG & Co.
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