Cylindrical filter panel screen for a water intake

Abstract

A device for filtering a stream of water in a channel (2), includes: a wall (6) adapted to be mounted in the channel and including a through-opening, a filter member (10) mounted on the wall opposite the through-opening and including a filter surface projecting relative to the wall, the filter surface having a larger area than would have a flat filter surface fitted in the through-opening, the filter member including retaining members face to face with the filter surface for retaining the bodies that do not pass through the surface, a suction device disposed facing the retaining members, and elements for driving the filter member and/or the suction device in a relative movement of one in relation to the other such that the suction device is successively brought face to face with each retaining member.

Claims

1. An installation comprising: a channel in which water flows, a water level in the channel being between a minimum water level and a maximum water level; and a device which filters a stream of water having at least the minimum water level in the channel, the device comprising: a frame-forming wall mounted in the channel and which comprises a substantially-central through-opening, a filter member mounted on the frame-forming wall at the through-opening, the filter member comprising a conical filter surface projecting relative to the wall in the upstream direction, the conical filter surface having a larger area than would have a flat filter surface fitted in the through-opening, the filter member comprising retaining members provided in front of the conical filter surface upstream thereof or downstream according to the direction of flow of the water, in order to retain solid bodies that do not pass through the conical filter surface, the filter member being movable, an uppermost portion of the filter member being disposed at most at the minimum water level during filtration of the stream of water flowing through the channel, at least one suction device which is disposed opposite the retaining members upstream thereof, and a drive system including peripheral gear teeth, a pinion, and a drive motor, the gear teeth extending from a peripheral end of the filter member and engaging with the pinion, the drive motor driving the pinion which engages the gear teeth for rotationally driving the filter member in a relative movement between the filter member and the at least one suction device such that each retaining member is successively brought in front of the at least one suction device in order to locally generate, through the filter member, a counter-flow of water successively opposite each retaining member.

2. The installation according to claim 1, wherein the axis of revolution of the conical filter surface is disposed perpendicularly to the through-opening of the frame-forming wall.

3. The installation according to claim 1, wherein the retaining members are disposed along generatrices of the conical filter surface.

4. The installation according to claim 3, wherein the retaining members comprise two partitions spaced apart, arranged along the generatrices of the conical filter surface.

5. The installation according to claim 1, wherein the suction device, or each suction device when a plurality of suction devices is provided, comprises a suction unit and a suction nozzle.

6. The installation according to claim 5, wherein the suction nozzle is of elongate general shape and comprises an envelope-forming wall which, in cross-section, has an open profile provided with an opening face to face with the retaining members.

7. The installation according to claim 6, wherein, in plan view, the opening has a substantially rectangular outline of dimensions equal to or greater than those of the facing retaining members.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other features and advantages of the invention will appear in the light of the following detailed description and drawings in which:

(2) FIG. 1 is a cross-section view of a water intake sluice equipped with a cylindrical filter panel screen/device according to the invention, viewed from upstream;

(3) FIG. 2 is an elevation view in horizontal cross-section on BB of FIG. 1;

(4) FIG. 3 is a horizontal cross-section view on CC of FIG. 1;

(5) FIG. 4 reproduces at a larger scale the details referenced D and E of FIGS. 1 and 2;

(6) FIG. 5 is a horizontal view of an embodiment of the invention; and

(7) FIG. 6 is a horizontal view of an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) As illustrated in the drawings, a filter device with a filter member having a cylindrical filtration surface such as a cylindrical filter panel screen 1 is installed in a water intake channel or sluice 2 whose parallel masonry walls 3 and 4 each comprise, facing each other, a vertical guide 5 (FIG. 3). An installation comprising the channel and the filtration device is represented in FIGS. 1 to 3.

(9) Such guides 5 are for example produced from metal and each form a groove as represented in FIG. 3.

(10) The sluice 2 is equipped with a frame-forming wall or carrier plate 6 extending from one wall 3 to the other 4 and which is slid vertically in the guides 5. The plate 6 comprises a circular opening 61 substantially centered on the axis 13 of the plate 6. The low part of the circular opening 61 is more generally situated very close to the bottom 14 of the sluice 2. The circular opening 61 is obstructed by a cylinder 7 concentric with the opening 61 and which projects upstream relative to the carrier plate or frame 6 (FIG. 3). The cylinder 7 is constituted by several spokes 8, a hub 9, and a filter member 10 fastened to the periphery of the cylinder 7. The spokes 8 extend from the hub 9 to the cross-members 11 and are generally regularly distributed around the hub. These spokes 8 are fastened to the filter member 10. Longitudinal partitions 12 spaced from each other delimit in pairs compartments or retaining members for the various solid bodies (detritus and particles) stopped by the cylindrical filtration surface of the filter member 10. For example, the width of the partitions 12 is several centimeters from upstream to downstream. The partitions 12 are disposed at the periphery of the cylinder 7 and extend radially outwardly of the filter member 10, on going away therefrom. The partitions 12 are arranged longitudinally along generatrices of the cylinder 7, over its entire height.

(11) The diameter of the cylinder 7 is preferably the greatest possible, that is to say slightly less than the width of the sluice 2, this being in order to maximize the area of the filtration surface. The height of the cylinder may also be modified and increased if need be. However, to avoid flexing of a cylinder that is too high under the action of its weight which, normally, would require the free end of the cylinder to be supported, it may be preferred to increase the diameter of the cylinder.

(12) It should be noted that the water flows as indicated by the arrows in FIG. 3 from the outside to the inside of the filter cylinder before escaping in the downstream direction via the central opening in plate 6.

(13) As a variant, the water flows from the inside of the filter cylinder to the outside and the retaining members are disposed inside the filter cylinder.

(14) The lowest water level denoted LWL is generally situated at least at the upper level of the cylinder (FIG. 1). As a variant, the level LWL may be higher or lower depending on ancillary constraints.

(15) The hub 9 of the cylinder is provided with mechanical journals and abutments known per se. The hub 9 is carried by a shaft 15 fastened to the plate or support wall 6 by radial arms 16.

(16) In order to prevent water from passing from upstream to downstream of the filter cylinder 7 without passing via the filter member 10, the plate 6 extends at least to a level generally equal to or greater than the highest water level HWL not represented in the drawings.

(17) As represented in FIG. 3, the cylinder 7 is obturated at its upstream end 7a which is opposite the downstream end 7b situated face to face with the central opening of the plate 6. The obturating wall 7a has for example a conical shape in this example for hydraulic reasons.

(18) The cylinder 7, centered the hub 9, is rotationally driven by drive means comprising peripheral gear teeth 17, a pinion 18 and a drive motor 19 (FIGS. 1, 3 and 4, detail E).

(19) It will be noted that a lip seal 20 is for example provided between the end 7b of the filter cylinder and the wall or plate 6.

(20) As a variant, as shown in FIG. 5, the filter member 10 which protrudes relative to the plate or wall 6 is conical with the base of the cone situated facing the opening of the plate or wall 6 and the point of the cone directed upstream.

(21) A suction device is added onto the filter cylinder, comprising a longitudinal tangential nozzle 30 (FIGS. 1, 2 and 4) extending over the entire length of a generatrix of the cylinder 7. The nozzle 30 is fastened to the carrier plate 6 by one end (FIG. 2). The nozzle 30 comprises a cylindrical surface open over its full height by a slot or opening 31 which is axially arranged, that is to say along the generatrices of said cylindrical surface and which faces towards the cylinder 7. The edges of the slot are then spread apart from each other in order to enlarge the slot.

(22) As represented in FIG. 1 and FIG. 4 (detail D) the cross-section of the nozzle thus formed has a U-shaped open profile the opening of which is directed towards the retaining members of the filter member 10.

(23) In practice, the outside volume of the cylinder 7 equipped with the filter member 10 is fragmented in a circular manner into compartments 32 by the parallel longitudinal partitions 12 forming the retaining members. In a plan view from the cylinder 7, the nozzle 30 has a rectangular outline equivalent to or somewhat greater than once that of such a compartment.

(24) The nozzle 30 has an opening 31 oriented to face the compartments 32 of the cylinder, which may be equipped with flexible lips 33, 34 in order to reduce the cross-section thereof, while enabling the occasional passage of bodies of greater size. The nozzle 30 is connected by a duct 35 to a suction unit such as a pump 40 fastened to wall 6, for example on the downstream side thereof. The pipe 35 thus for example passes through the wall 6 and provides the fastening of the nozzle 30 thereto.

(25) The pump 40, supplied with power for example via a cable (not shown), is chosen so as to be able to pump large items of debris and, when necessary, of a type also capable of ensuring a very high survival rate for fish. The water conveying debris, fish and other forms of aquatic life is removed to its collection point by a duct 50.

(26) As a variant, the suction device comprises two nozzles disposed respectively on opposite sides of the cylindrical filter member or panel, one downstream relative to the direction of the outgoing stream, the other upstream. These two nozzles are arranged in register with each other and are each turned towards the cylindrical filter panel in cooperation with the relative rotary movement and a pump whose discharge is connected to the nozzle is disposed downstream of the cylindrical filter panel.

(27) According to another variant, the take-off pipe 50 comprises two debris concentrators (not shown) and a set of valves enabling alternate use of one of the concentrators or the other.

(28) In a configuration with fish to save, the take-off pipe lacks any concentrator and the water loaded with debris and fish is discharged directly into a pipe or channel for return to the natural environment.

(29) In FIGS. 1 to 3, an embodiment has been shown in which the suction device 30, 40 is fixed, whereas the drive means 17, 18, 19 are adapted to rotate the cylindrical filter member or panel.

(30) As a variant (not shown), the filter member or panel is fixed whereas the drive means are adapted to rotate the suction device.

(31) According to another variant (not shown), the drive means are adapted/configured to rotate both the suction device or devices (if there are several) and the cylindrical filter panel.

(32) The description which has just been given in particular concerning the compartments, the suction device or devices, the relative movement between that device or devices and the filter member applies whatever the form of the filter member.

(33) However, for a filter member of non-cylindrical form, such as frusto-conical (FIG. 5) or conical (FIG. 6), the retaining members or compartments have different suitable shapes (for example, a generally triangular shape for a cone), the same applying for the suction device.

(34) The operation of the screen is the following: when not moving, the filter cylinder 7 is stopped, the pump 40 does not operate and the water flows through the filter member. Debris is stopped by the filter member 10 and retained in the longitudinal compartments 32 at the periphery of the cylinder. When it is desired to clean the filter 7, the pump 40 is started and the cylinder is rotated by the drive means 17, 18, 19. The cylinder turns and the peripheral compartments 32 pass in turn in front of the opening 31 of the nozzle 30. Each compartment is isolated from the general stream by the nozzle facade. The suction of the pump creates a flow in the compartment in the opposite direction to that of the normal screening and with a speed of the same order. The debris are sucked into the nozzle 30, though the pump 40, and are removed by the pipe 50.

(35) If a piece of debris of large size situated in a compartment 32 jams the rotation of the cylinder, the drive system 17, 18, 19 stops by the effect of a load limiter known per se and rotation in the opposite direction is triggered, generally making it possible to get rid of the debris causing the jamming.

(36) The washing pump 40 and the rotary movement are stopped at the end of the washing cycle.

(37) When it is required to retrieve alive the fish and other forms of aquatic life stopped on the filter cylinder, the pump used is a suitable type known per se. The operation is normally automatic and controlled by the head loss generated by the filter cylinder, that is to say upon its fouling. Devices already known in themselves ensure the safety of the installation.

(38) The size of the pieces of debris to suck away is limited by the grating of bars present in such water intake constructions. Those pieces of debris may then be stored while awaiting washing by virtue of the dimensions of the compartments, in particular thanks to the distance between the filter member surface and the free end of the longitudinal partitions of said compartments.

(39) It is to be noted that the filtration device or screen according to the invention prevents any possibility of by-passing the system.

(40) It does not generate significant turbulence in the outgoing stream either. It is thus more efficient than a dual flow band screen.

(41) Such a device/screen according to the invention has the advantage of being able to be inserted by sliding in the vertical guides cooperating with bearing structures for thru-flow band screens.

(42) The filter member 10 may have mesh openings of cylindrical, rectangular or square shape or slots with respective dimensions of the order of 1010 to 0.50.5 mm.

(43) The device/screen according to the invention also has an application for sluices that are inclined relative to the vertical plane.

(44) It may even be mounted with the vertical axis and an outlet in a tunnel under the deck.