GB2307984A

GB2307984A - Detecting foreign particles in flow of fibres

Info

Publication number: GB2307984A
Application number: GB9524963A
Authority: GB
Inventors: Hubert Hergeth
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-08-28
Filing date: 1995-12-06
Publication date: 1997-06-11
Anticipated expiration: 2015-12-06
Also published as: GB9524963D0; DE4430332A1; IT1281744B1; ITMI951805A1; ITMI951805A0; GB2307984B

Description

2307984 1 DEVICE FOR DETECTING FOREIGN PARTICLES IN A FIBRE LINE This

invention relates to a part of a machine for detecting and eliminating foreign particles in a textile flock processing line.

For some years, proposals have been made and experiments carried out to remove foreign particles, e.q. shreds of material, found in cotton bales from the cotton mixture before spinning. In these proposals, cotton flocks are conveyed through a shaft, the shaft wall of which consists partly of glass at least on one side. Cameras which view the flocks are situated behind the glass and are positioned at a distance of 0.5 to 1.5 m from the glass in these proposals. The cameras comprise a lens system and photodiodes. The signals from the photodiodes are processed and transmitted as signals to a computer which evaluates the camera signals in order to assess the flocks.

The disadvantage in these proposals is the expensive camera system and the distance between the glass plate and camera. The interspace must be free from dust and uncontrolled light influences so as not to impair the measurement. Costly enclosures and filters are required to keep the space between the glass plate and camera free from dust. The object of the invention is to provide a device in which no dust problem arises and the illumination of the fibres is carried out optimally.

This is achieved by the use of glass fibre conductors and the placement, according to the invention, of the elements in the machine. Optical colour sensors comprise one or more photodiodes which detect colours by means of upstream colour filters. In order to be able to direct the light waves better onto the photodiodes, lenses are used. It is known to 2 use glass conductors to relay the optical signals from a collection point to the sensor. From medical technology, it is known, for the purpose of illuminating the object to be examined, to use glass fibres to relay a light source and to bundle these glass fibres of the light source together with the glass fibres of the optical sensor. Illumination and viewing of an object then take place by means of a common objective or the end of the combined glass fibre bundle.

The invention will further be described, by way of example, with reference to the accompanying schematic drawing.

The fibres (2) are collected in a shaft (1), drawn off from there by means of a conveying device and conveyed past a glass surface (6). The glass (6) and the conveyor belt (3), which is guided over rollers (4), form a shaft space, the depth of which can be seen in the drawing. The system as a rule extends over about one meter in width. The optical system comprises the actual sensor (12) with the photodiodes which relays the results to a computer (13). The illumination is carried out by means of a light source (10). Light guides (11) lead from the sensor and the illumination source to a bundle module (9) which is connected by means of light guides (11) to the objective (8) or to the end piece of the optical system. The objective or end piece may include an end lens (7).

According to the invention, this end lens is brought right up against the glass plate. The end lens may be adhesively bonded to the glass plate. As a result, a connection which is free from the influences of dust is obtained between the glass plate and sensor. Furthermore, influences due to reflections on the glass plate are avoided. The device described 3 allows trouble-free operation in the dusty environment and eliminates extraneous light influences.

4

Claims

1. An optical device for use in a machine for detecting foreign particles in a fibre line, comprising a plurality of optoelectronic sensors arranged to monitor the fibre flow through a glass wall of a shaft, wherein the interspace between a part of the lens system of the optical device lying closest to the glass plate and the surface of the glass wall facing away from the fibres is smaller than the distance between the glass plate and the opposite shaft boundary wall.

2. A device as claimed in Claim 11 wherein the lens system is pressed or adhesively bonded onto the glass plate.

3. A device as claimed in Claim 1 or Claim 2, further comprising detection means and object illumination means having a common exit and entrance opening at the system boundary of the optical sensor opposite the glass plate.

4. An optical device substantially as hereinbefore described with reference to the accompanying drawing.

5. A machine including a textile flock processing line and an optical device of the type claimed in any one of the preceding claims for detecting the presence of foreign particles in the flock.