FIELD OF INVENTION

The present invention relates to textile machines. More particularly, the present invention relates to a filter screen arrangement of spinning preparatory machines such as draw frame.

BACKGROUND AND PRIOR ART

Normally, during the operation of textile machines, airborne fiber and fiber particulate are generated. This is pneumatically suctioned off and transferred to a filter by air stream transport. The filter retains the fibrous material and permitting the air to exhaust through an outlet source.

In draw frame, a suction arrangement is provided to collect the airborne fiber and fiber particulates generated in various parts of the machine such as scanning roller, drafting and delivery zone. For filtering the fibers from a stream of air, the stream is passed through a filter which retains the fibers alone and releases the air. This fibrous material builds up firmly on the filter and thus reduces the suction effect. In order to maintain the uniform pressure of the suction system, the filter is cleaned by means of a scraper blade in a frequent interval. The fibrous material cleaned by the scraper blade can fall from said scraper blade into the bottom portion from which it can be disposed off either manually or automatically at a convenient time.

In the existing draw frames, the suction arrangement consist a collection chamber and a vacuum chamber and the both are separated by means of a filter screen and rectangular wall. Said filter screen is made up of steel and is affixed on the outer frame of the rectangular wall of the collection chamber using a rectangular steel frame and fastening means. The filter screen is being held between the outer frame of collection chamber and rectangular steel frame. Due to the continuous pressure applied on the filter screen by means of suction and movement of scraper blade, undulations are formed in the surface of the filter screen or the over all surface become concave in shape. Due to this, the scraper blade can not remove all the fibres deposited over the surface of filter screen.

This would lead to reduction in suction pressure and affects the cleaning efficiency of suction arrangement.

The scraper blade provided to clean the surface of filter is run over the filter screen, cleans the surface and returned to its original position. In order to execute this process, a pneumatic cylinder is provided to impart the scraper blade for the desired movements. Since the filter screen is rectangular in shape and the scraper blade swivels in an arcual manner, it can not clean the entire surface of rectangular filter and a part of the screen always remain unclean. This would also affect the suction pressure and cleaning efficiency of the suction arrangement.

There has thus been a persistent need to develop a filter screen arrangement that would overcome the disadvantages present in the existing textile machines especially draw frames.

OBJECT OF THE INVENTION

It is thus the basic object of the present invention is to provide an improved suction arrangement which improves the cleaning efficiency of the suction arrangement of draw frames compared to the prior art machines.

Yet another object of the present invention is directed to provide a textile draw frame with improved filter screen arrangement that facilitates effective functioning of scraper blade arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig - 1 of the drawings illustrates existing suction arrangement of the textile draw frames.

Fig - 2 of the drawings illustrates filter screen arrangement of the existing draw frame.

Fig - 2a of the drawings illustrates the side view of filter screen arrangement of the existing draw frame.

Fig - 3 of the drawings illustrates the filter screen arrangement of the draw frame according to the present invention.

Fig - 3a of the drawings illustrates the side view of filter screen arrangement of the draw frame according to the present invention

SUMMARY OF THE INVENTION

Fig - 1 of the drawings describes the suction arrangement of the existing draw frames. The suction arrangement (1) is a component of an entire drawing frame. Suction tubes are provided in the various parts of the draw frame to create a suction air stream, with the help of which loose fibers and airborne particulates of said zone are conducted away and are led to the suction arrangement. Said suction arrangement (1) includes a vacuum chamber (2) and a collection chamber (3). The suction arrangement (1) is essentially closed on all sides and exhibits generally the technologically necessary openings for one or more pipes for the introduction of the air stream carrying the fibrous particulate and an additional opening for the periodic removal of the fibrous materials accumulated in the collection chamber (3). The suction chamber (2) is comprised of a drive motor, a fan and an exhauster to create suction which operates in a conventional way. The vacuum chamber (2) and the collection chamber (3) are separated by means of a wall (4) which comprises a filter screen (5).

Fig - 2 and 2a of the drawings describes the filter screen arrangement of the existing draw frames. The filter screen (5) is affixed on the rectangular wall (4) using a rectangular steel frame (6) and plurality of fastening means (7). The filter screen (5) is being held between the rectangular wall (4) and rectangular steel frame (6). During operation of draw frame, the fibrous material accumulates on the intake side of the filter screen, which is on its side facing the collection chamber (3). This material is scraped off by a scraper blade (8) from the surface of filter screen (5).

In the existing arrangement, as shown in Fig - 2 and 2a, the scraper blade (8) is pivotably mounted in the bottom portion of the filter screen through the hinge point (9) and operated by means of a pneumatic cylinder (not shown). The scraper blade (8) lies over the steel frame (6) which has a thickness of 3 to 5 mm which does not allow the scraper blade (8) to make a uniform contact with the entire surface of filter screen. This would affect the efficient cleaning of the scraper blade. Also, the scraper blade can not remove all the wastes accumulated on the surface of filter screen by its arcual movement. A
particular area (A) as shown in Fig 2 is always remain unclean. This would lead to reduction in suction pressure and increases the power consumption. Moreover, due to the continuous pressure applied on the filter screen (8) by means of suction air and scraper blade (8), undulations formed in the surface of the filter screen or the over all surface become concave in shape over a period of time. Hence the scraper blade can not touch the filter screen uniformly and therefore cannot remove all the fibre particulates deposited on the deformed surface of filter screen. This would also lead to reduction in suction pressure and affects the cleaning efficiency of suction arrangement.

Fig 3 and 3a shows the improved filter screen arrangement (11) in accordance with the present invention. Two circular frames (12) and (13) are joined together by means of any fastening method for example spot welding. The outer diameter of circular frame (13) is lesser than the outer diameter of circular frame (12), but the inner diameter of both circular frames are equal. The joining of circular frames (12 and 13) forms an inner frame (14) with a 'L' shaped flange on its outer surface. The filter screen (15) is affixed on the inner frame (14) using another circular frame (16) and plurality of fastening means (17). Alternatively, the filter screen is welded or pasted on the outer surface of inner frame (14). The filter screen (15) is being held between the inner frame (14) and outer circular frame (16). The entire arrangement is mounted on the separation wall (4) of the suction arrangement (1).

The shape of the frames (12, 13 and 16) are not limited only to circular form and it can be arranged in the form of square, rectangular or any other desired form according to the requirement.

In the filter screen arrangement according to the present invention, as the filter screen (15) is held between the frames 12, 13 and 16, the surface deformation is eliminated. The surface of filter screen is projected out from the outer frame (16) and this helps the scraper blade to clean the filter effectively. Since the shape of the filter screen is circular and the movement of the scraper blade is arcual, the scraper blade can clean the entire surface. The contact between the scraper blade and filter screen is equal to its entire length, so that the pressure applied by the scraper blade over the filer screen is uniform. By all this means, uniform suction and effective cleaning is achieved by the suction arrangement.

We Claim:

1. A filter screen arrangement for textile machine comprises, a filter screen (15) wherein said filter screen (15) is being held between the inner frame (14) and outer frame (16).

2. A filter screen arrangement for textile machine as claimed in claim 1, wherein said inner frame(14) is configured by joining plurality of frames (12,13).

3. A filter screen arrangement for textile machine as claimed in claim 2, wherein the outer diameter of a frame (13) is lesser than the outer diameter of the frame (12) and their inner diameter are equal.

4. A filter screen arrangement for textile machine as claimed in claim 3, wherein the inner frame (14) is formed by joining frames (12,13).

5. A filter screen arrangement for textile machine as claimed in claim 4, wherein the filter screen (15) is being held between the inner frame (14) and outer frame (16) by fastening means (17).

6. A filter screen arrangement for textile machine as claimed in claim 5, wherein the frames(14,16) holds the filter screen (15) firmly to project out the surface of the filter screen(15) from the surface of the outer frame (16).

7. A filter screen arrangement for textile machine as claimed in claim 6, wherein the filter frame can be in any desired forms such as circular, square, rectangular, etc.

8. A filter screen arrangement for textile machine as claimed in claim 1, wherein said filter screen (15) is cleaned by the arcual movement of scraper blade (8).

9. A filter screen arrangement for textile machine as claimed in claim 8, wherein said scraper blade (8) applies uniform pressure over the filter screen (15).