WO2002057549A1

WO2002057549A1 - A self-cleaning filter grating

Info

Publication number: WO2002057549A1
Application number: PCT/DK2002/000019
Authority: WO
Inventors: Kaj Stjernholm
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-01-18
Filing date: 2002-01-11
Publication date: 2002-07-25
Anticipated expiration: 2003-07-18

Abstract

The present invention relates to a self-cleaning filter grating which is constructed such that the grating consists of discrete parallel stay-shaped filter elements, which may be moved alternately relative to each other, thereby ensuring that material braked by the filter grating does not get stuck in the filter grating, but is pushed away from the filter by the mutual movement of the filter elements, said filter being thus self-cleaning.

Description

A self-cleaning filter grating

The present invention relates to a self-cleaning filter grating which is typically used in connection with the filtration of overflow water from sewer systems, where the water from the overflow channels is to be conveyed to a cleaning system.

An ordinary filter grating which is not self-cleaning will naturally stop the material which is entrained by the water that is to be cleaned, but at _. some time the grating will be clogged and therefore block the flow of the water. A non self-cleaning grating will therefore require frequent manual cleaning, which, of course, is exacting in terms of resources and costs.

Accordingly, for operating, hygienic, practical and economic reasons it is therefore essential to the practical use of filter gratings that these are self-cleaning.

It is known from the patent specification EP 0 358 952 B1 to manufacture a self-cleaning filter grating that uses a carriage which is capable of travelling along the parallel grating elements and of pushing the collected material away from the grating, thereby maintaining the water flow.

The use of the carriage involves several drawbacks, e.g. it cannot pass 5 an obstacle which is stuck in the grating, if it takes a greater force to remove the obstacle than the one which the carriage can supply. In such a situation, the grating will therefore not be cleaned in the area which is disposed after the blocking material, which reduces the efficiency of the filter grating of course.

- Another drawback of the self-cleaning grating using a carriage for performing the self-cleaning effect, is that for a given period of time the grating is cleaned only in the area which the carriage has traversed. The object of the present invention is to provide a self-cleaning grating which does not have a travelling cleaning carriage, and which, continuously and independently of time, keeps the entire grating cleaned uniformly. Also, the invention ensures that the grating may be cleaned over its entire effective area, even if, at one or more locations, the grating is blocked by stuck material from the water which is to be cleaned.

The invention will be explained below in a preferred embodiment with reference to the accompanying drawings.

Fig. 1 shows the complete grating from above (Fig. 1-A) and from the side (Fig. 1-B). The grating consists of parallel grating elements with gaps for the passage of the water which is to be cleaned. The parallel grating elements are visible in Fig. 1-B.

The grating will filter all particles larger than the gap between the individual grating elements. At the end of the grating, a motor is arranged on the top, driving a shaft that runs through all the grating elements.

Fig. 2 is a view of some of the individual grating elements arranged in the grating housing, seen from above.

In Fig. 2-A, one of the otherwise identical grating elements is shown in accentuated gray/black view. The ends of each grating element are formed with a hole which is larger than the diameter of the shaft that passes through all the elements. A disc having a spline hole fitting the spline in the shaft from the motor arranged on the top of the grating, is placeςf in the holes in the grating elements. The spline hole in the discs is either positioned in the centre of the disc or eccentrically.

The grating elements, which are positioned in parallel on top of each other with a gap between them for the flow of the water which has been filtered, are now alternately provided with discs having centered spline holes or discs having eccentric spline holes. When the shaft rotates, the grating elements will therefore alternately be fixed in the same position or perform a rotary movement determined by the eccentrically arranged spline holes.

0 Fig. 2 B shows how the grating elements provided with discs having centered spline holes are always in the same position independent of the rotation of the drive shaft, while the grating elements provided with the , eccentrically arranged spline holes will move as a function of the rotation of the drive shaft.

Figs. 3 and 4 show in cross-section how the cleaning elements are 0 alternately fixed and move in the horizontal plane in a circular movement.

When the grating is in operation, the motor driving the drive shaft will 5 rotate. This means that every second grating element will perform a movement which is circular and parallel with the fixed adjacent elements.

A body which has been braked by the cleaning grating will now be _n pushed away from the grating, while the body is moved in one specific direction in parallel with the grating surface as a consequence of the discontinuous movements which are generated by every second grating element. 5

Fig. 2 shows in point C a cleaning comb which consists of a plate which is arranged transversely to the parallel grating elements, and which has 0 teeth extending into the gaps between the grating elements.

The cleaning comb is also shown in another section in fig. 4. The _. cleaning comb has the function that it will brake the filtered objects which are pushed along the cleaning grating, thereby allowing the filtered objects to be collected and conveyed away from the cleaning grating. In addition to conveying the filtered material away, the cleaning comb has the additional function that it prevents the parallel filter elements from bending downwards, which might be a problem in long gratings manufactured in accordance with the present invention.

Of course, self-cleaning filter gratings manufactured in accordance with the present invention may be used in many other connections than the cleaning of water mentioned here.

List of figures:

Fig. 1 shows an example of a self-cleaning filter grating manufactured in accordance with the present invention. Fig. 1 A shows the filter seen from above. Fig. 1 B shows the filter seen from the side.

Fig. 2 shows an example of a filter grating having alternately movable and fixed parallel stay-shaped grating elements.

The left half of the figure shows the movable grating elements in four different positions as a function of the angle of rotation, shown in steps of 90 degrees, of the rotating eccentric drive elements. The right half of the figure shows how the fixed grating elements are positioned. The filter in the shown example is constructed such that the grating alternately has fixed and movable grating elements.

Fig. 3 shows in a section taken in the longitudinal direction of a self- cleaning filter how the filter elements are moved mutually in three phases of the angle of rotation of the eccentric drive elements. In fig. 3, the filter elements are alternately fixed and movable.

Fig. 4 shows in a section taken in the longitudinal direction of a self- cleaning filter how the filter elements are moved mutually in three phases 1 of the angle of rotation of the eccentric drive elements. In fig. 3, the filter elements are alternately fixed and movable. Fig. 4 A shows a couple of the moving elements. Fig. 4 B shows a couple of the fixed elements. Fig. 4. C shows the cleaning comb.

1° Fig. 5 shows a photo of a self-cleaning filter grating produced with two combs in water action.

_{ι JΓ} Fig. 6 shows a photo of a self-cleaning filter grating produced with two combs in water action.

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Claims

PATENT CLAIMS

1. A self-cleaning filter grating for the removal of particles from media flowing through the grating, which consists of parallel elements with gaps for the passage of the flowing medium, characterized in that the parallel elements are mutually movable, thereby preventing particles in the flowing medium from getting stuck between the parallel grating elements.

2. A self-cleaning filter grating according to claim 1 , characterized in that the parallel elements of the grating are alternately fixed and movable.

3. A self-cleaning filter grating according to claim 1 or 2, characterized in that the movement of the mutually parallel elements takes place such that the braked particles from the flowing medium are moved in one specific direction.

4. A self-cleaning grating according to claim 1 , 2 or 3, characterized in that the grating is provided with a particle trap for the discharge of the braked particles.

5. A particle trap according to claim 4, characterized in that it consists of a plane face which extends transversely to the parallel grating elements.

6. A particle trap according to claims 4 and 5, characterized in that the particle trap is provided with elements which extend from the plane face and are positioned between the mutually parallel grating elements.