FILTERING DEVICE AND SYSTEM, METHOD OF INSTALLING A FILTERING DEVICE AND USE OF A FILTERING DEVICE

Abstract

The invention relates to a filtering device for filtering fibrous material from water flowing through a channel, the device comprising a sieve, the sieve being arranged at an angle with respect a flow direction defined by the channel. According to the invention, said angle is smaller than 25°. The invention also relates to a method of installing such a filtering device, a system comprising such a filtering device, and the use of such a device.

Claims

1. A filtering device for filtering fibrous material from water flowing through a channel, the device comprising: a sieve, the sieve arranged at an angle with respect a flow direction defined by the channel, wherein said angle is smaller than 25.

2. The filtering device according to claim 1, wherein an aperture size of the sieve is 0.8 mm or larger.

3. The filtering device according to claim 1, wherein the sieve is flat.

4. The filtering device according to claim 1, the sieve comprising apertures of substantially circular shape.

5. The filtering device according to claim 1, further comprising mounting means for fixedly connecting the sieve with respect to the channel.

6. The filtering device according to claim 1, further comprising at least one wiper which is movable over and/or across the sieve.

7. The filtering device according to claim 6, further comprising a skimmer for cleaning the wiper.

8. The filtering device according to claim 6, further comprising an actuator for moving the at least one wiper.

9. The filtering device according to claim 8, further comprising an endless support element configured to be driven in rotation by the actuator, the wiper being fixed with respect to the endless support element.

10. The filtering device according to claim 6, the device further comprising means for preventing and/or limiting tilting of the wiper with respect to the sieve.

11. The filtering device according to claim 10, wherein the means for preventing tilting of the wiper comprise at least one follower mounted to the wiper and at least one guide track for guiding the at least one follower along the at least one track, the follower cooperating with the at least one track in order to prescribe an orientation of the wiper while the follower is guided by the track.

12. The filtering device according to claim 7, wherein the wiper is tiltably supported with respect to the skimmer at least while it is in contact with the skimmer.

13. A method of installing a filtering device for filtering fibrous material from water flowing through a channel, the method comprising: installing a sieve in the channel at an angle with respect to a flow direction defined by the channel, wherein said angle is smaller than 25°.

14. The method according to claim 13, further comprising manufacturing the sieve at a location different, for instance remote from, the channel

15. A system for filtering fibrous material from water flowing through a channel, the system comprising said channel and a device according to claim 1.

16. The system according to claim 15, wherein the channel is an open channel.

17. The system according to claim 15, wherein the channel is made of concrete.

18. A method for removing fibers from water, the method comprising: using the device according to claim 1 for removing the fibers from the water.

19. The method of claim 18, wherein the water is municipal or industrial waste water.

20. The method of claim 18, further comprising removing the fibers from the water as the water flows through the channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The invention will be further elucidated with reference to the adhered drawings, in which:

[0058] FIGS. 1A-1C schematically respectively show perspective, top and side views of a system for filtering fibrous material; and

[0059] FIGS. 2 and 3 show details of parts of the system of FIGS. 1A-1C. Throughout the figures, like elements are referred to using like reference numerals.

DETAILED DESCRIPTION

[0060] The figures show a system 1 for filtering fibrous material from water flowing through a channel 2. The channel 2 is herein formed by a concrete floor 3 and concrete walls 4, 5, which together define a u-shape as seen in transversal cross section of the channel 2. In the channel 2, a device 50 is installed for filtering fibrous material from water flowing through the channel 2. The device 50 comprises a sieve 6. The sieve 6 is flat, and is perforated with circular apertures having a diameter of 1.5 mm. The channel 2 defines a flow direction F, in the figures from left to right. The channel 2 shown herein, is arranged approximately horizontally. As such, the flow direction F is substantially horizontal. The sieve 6 is arranged at an angle a with respect to the flow direction F, in particular at an angle with the horizontal plane as seen in the flow direction F. The angle α is relatively small, in the chosen example 15°. Angles been 10° and 20° have been found to be desirable.

[0061] The sieve 6 is arranged in the channel 2 so that in order for water to pass through the channel 2, it has to pass through the sieve 6. As the sieve 6 is arranged relatively horizontally, i.e. the angle α between the sieve 6 and the horizontal is relatively small, a projection of the apertures of the sieve 6 in a vertical plane P normal to the flow direction F is relatively small. As such, the relatively large apertures of 1.5 mm diameter still effectively prevent fibrous material from passing through the sieve 6, while letting through a relatively large amount of water relatively easily.

[0062] During using, a filter cake builds up on the inlet side (i.e. upstream side) of the sieve 6. The filter cake consists of material, generally fibrous, that is unable to pass through the sieve 6. In order to prevent the filter cake from blocking water through flowing through the sieve 6, the device 50 comprises a wiper 7. In use, the wiper 7 moves over the sieve 6 in order to wipe the filter cake from it. To show the movement of the wiper 7, it is redrawn at several locations as wiper 7′ along the path taken by the wiper. As such, the device 50 of the figures, actually only has one wiper 7. Nevertheless it is possible to use several wipers 7 if desired. Shown as an example, the wiper 7 is formed as a brush. The wiper 7 moves along the sieve 7 in the flow direction F, thereby wiping filtered material towards an upper end 8 of the sieve 6. Directly below the sieve 6 at its upper end 8 a receptacle 9 is arranged. The receptacle 9 catches filtered material deposited over the upper end 8 of the sieve 6 by the wiper 7. In order to skim filtered material from the wiper 7, a skimmer 10 is arranged near the upper end 8 of the sieve 6. The skimmer 10 is arranged stationary with respect to the channel 2 and the sieve 6 by mounting it to the walls 4, 5 of the channel 2. When moving, the wiper 7 passes the skimmer 10, thereby skimming filtered material off itself. As the skimmer 10 is arranged above the receptacle 9, skimmed material drops down into the receptacle 9.

[0063] Movement of the wiper 7 is effected via a chain system. The wiper 7 is connected to two carriages 11. Each of the carriages 11 is connected to a chain link 12 of an endless chain 13. Each chain 13 is guided by two sprockets 14 supported on axles 15 near the lower and upper 8 end of the sieve 6. The axle 15 near the upper end 8 of the sieve 8 is driven by a synchronous electric motor 16. As such, the wiper 7 moves along the path of the chains 13 upwards along the sieve 6. The wiper 7 moves back towards the bottom of the sieve 6 at a distance thereof. In order to prevent the wiper 7 from tilting due to between the wiper 7 and the sieve, the wiper 7 is rigidly connected to a follower 17 on both its sides (see FIG. 2). The channel 2 is provided with a guide track 18 (see FIG. 3). The guide track 18 opens near the bottom of the sieve 6 (FIG. 2) in order to receive the followers 17. While the wiper 7 moves along the sieve 6, the guide track 18 prevents the wiper 7 form tilting with respect to the sieve 6 via the followers 17. The guide track 18 ends at the upper end 8 of the sieve 6, at a distance before the skimmer 10. As such, the wiper 7 is left free to tilt at the skimmer 10, thereby improving its skimming effect.

[0064] Directly aft of the wiper 7, as seen in the direction of movement thereof, and attached to the wiper 7, is a sieve cover 19. The sieve cover 19 moves with the wiper 7. The sieve cover 19 covers the sieve 6 directly aft of the wiper. The sieve cover 19 is flat and parallel to the sieve 7, at least while the wiper moves along the sieve 6. The sieve cover 19 moves at a distance d from the sieve 6, the distance being 1 cm, although smaller distances could be chosen.

[0065] The filter system 1 in the figures can be used for removing fibers from water, in particular for filtering municipal or industrial waste water.