CLEANING APPARATUS FOR SEPARATION SCREENS

Abstract: Cleaning apparatus for separation screens intended for water inlets to turbines, intakes to turbines, intakes at wastewater treatment plants and the like and which cleaning apparatus includes a cleaning element which is movable, at least along the screen in vertical direction and mounted on a support or on a carriage. The purpose of the present invention is to provide a relatively easy and flexible cleaning apparatus which only needs a small space and which may work with a movable cleaning element down to great depths without that the support or the carriage are exposed to unfavourable uneven loads or which results in an extensive overdimension of the cleaning apparatus. This has been solved thereby that the cleaning element (10) includes at least two essentially parallel rakearms (24) fixedly connected to each other by help of connection elements (25-29), and that the rakearms (24) consist of telescopically movable sections (11), the ends of which are interconnected in pairs by cross springers (28).

Description: Cleaning apparatus for, separation screens The present invention refers to a cleaning apparatus for c cleaning of e.g. separation screens at turbine water inlets, fresh water intakes, intakes at waste-water treatment plants and the like, which cleaning apparatus includes a cleaning element which is vertically movable along the screen and mounted on a support or on a carriage, whereby the cleaning , Q apparatus is movable sidewards by means of the carriage or the like. Accumulation of waste material, jam of logs and other contaminations at such separation screens result i.a.in a - j c decrease in the amount of water which passes through the screen and this reduces i.a. the production of electricity at the water power station, or alternatively that the water level outside the screen increases, which results in a risk for flood. Removal of such contaminations is often very Q expensive and difficult to execute. At plants where the separation screens are very deep it is necessary to use cleaning elements which are long enough in order to remove contaminations along the whole screen. As 5 the rake, which scratches against the -screen, must be drawn up above the water surface the cleaning element will stick up a considerable distance above the machine if it consists of a rigid rod or the like, and exerts heavy strains on the machine in this position. Furthermore it is required a large free area above the cleaning apparatus, which area is not always available. At depths down to 5 meters it has been possible to control the cleaning element without that the support or the carriage ' has been provided with reinforcements. At greater depths it is necessary to use 5 other means, e.g. to apply fixedly mounted control devices in or at the screen, which control devices reach all the way down to the bottom part of the separation screen and along which control devices a movable rake is arranged. Such a control device could not be used by one laterally movable cleaning apparatus. Furthermore the cleaning elements at such systems often are located in the water, which also concerns the control apparatus of the rake, whereby this is exposed to the power of objects floating in the water and contaminations which are transported along the screen by the rake. The reliability in operation for such devices is therefore low. At greater depths the dimension of the rake element must be strongly increased, which influences the weight of the devices and above all, the flow resistance of the rake element is increased. This causes great strains on the entire cleaning apparatus. Relatively great side deflections of the rake elements may occur as the water flow is at right angles to the screen only in exceptional cases. This may result in considerable difficulties when the rakearm move upwards, owing to the increased resistance against lifting which occurs due to the deflection. The purpose of the present invention is to provide a relatively easy and flexible cleaning apparatus which only needs a small space and which can work with a movable cleaning element down to great depths without the support or the carriage being exposed to unfavourable uneven loads or which results in an extensive overdimensioning of the cleaning apparatus. This has been solved thereby, that the cleaning element includes at least two essentially parallel rakearms fixedly connected to each other by help of connection elements, and that the rakearms consist of telescopically movable telescopic sections, the ends of which are interconnected in pairs by cross springers. The invention will here below be further described in embodiments with reference to the enclosed drawings. Figure 1 shows a side view of the cleaning apparatus with the cleaning element in a position above the surface of water, Figure 2 shows the cleaning element according to figure 1 in OMP a front view , Figure 3 shows the upper part of a cleaning arm, Figure 4 shows the cleaning arm according to figure 3 in a view from above, Figure 5 shows a side view of the pulley which is arranged on the upper part of the cleaning arm, more in detail, Figures 6-8 show schematically a two-, a three- and a four- section rakearm resp. The cleaning apparatus according to the invention is arranged to co-operate with a separation screen and includes two carriages 2a,b (only one is shown in figure 1) which, by help of guide rollers 3, engaged with rail tracks 4, fitted to a tubular formed beam or stand 5, may be moved along the screen 1. The carriages are connected to each other on a certain, adjustable distance from each other. They are moved along the screen by means of a worm gear motor, which pulls the carriages along the working path by help of a fixed roller chain. The carriages 2 support the hydraulic and/or the electric/electronic equipment used to control the cleaning apparatus. A hydraulic pendulum cylinder 6 is pivotably arranged at the upper part of each of the carriages 2 (of which only one is shown in figure 1) . The rod pistons 7 of the pendulum cylinders 6 are also pivotably connected to the upper part of a guide 8 of the rakearm in which a cleaning element 10 is supported. The lower part of the rakearm guide 8 is pivotably arranged in an attachment 9 which projects from each associated carriage 2. By this design the angle of the rakearm guides 8, by help of the hydraulic cylinder 6, may be arbitrarily varied in relation to the separation screen 1. The cleaning element 10 consists of two parallel rakearms 24, each of which consists of a number of telescopically movable sections lla,b,c etcetera with successively decreasing dimensions and which can be pulled together to one unit. The uppermost section 11a consists of a square tube while the other sections have circular cross sections. OMPI Hereby approximately 25 percents lower flow resistance is obtained in the water and a lower pulling resistance is achieved when the rakearms 24 are moved upwards, even if some lateral deviations may occur. A rake 14 is connected to the lowest section which rake delivers objects, which has been brought up, to a collecting trench 15. At the upper or lower part of each rakearm guide 8 there are arranged guide rollers 16 in pairs, controlling the main section 11a of the cleaning element 10. By help of these guide rolls 16 the main sections 11a may move freely up and down hanging in a wire fixed e.g. at the bottom of the rakearm guide 8. A hydraulic cylinder 17 is fixed to the lower part of each rakearm guide 8 and is located, at some, distance from and parallel to the rakearms 24 respectively. The hydraulic cylinders 17 are longer than the rakearm guides 8 and project up above these. The hydraulic cylinders 17 follow hereby the angle movements of the rakearm guides 8. At each upper part of the rod piston 18 are arranged pulleys 19, each of which consists of two wire guides 20, 21. A wire 22 runs from a first wire attachment in the upper- part of each rakearmguide 8 up over the first wire guide 20 located at the upper part of the rod piston 18, thereafter down and around a second, lower wire guide 23 arranged at the upper part of the rakearmguide 8, thereafter again up and over the third wire guide 21 and finally down to a second wire attachment located at the lower part of the main section 11a of the rakearms 24 respectively. In this way it is achieved an invertedly two-fold pulley, by which the main sections 11 of the rakearms 24 will move a distance which is four times as long as the distance which the piston rod 18 of the hydraulic cylinders 17 will move. The gear change between the main sections 11a of the rod pistons 18 and the rakearms 24 is therefore 1:4. The movements of the rakearm 24 in vertical direction may also be executed by arranging, at their lower parts roller chains, which by rollers may pass driven (e.g. by hydraulic engines) chain wheels mounted in the rakearm guides 8 and thereafter via other rollers up to the upper ends of the rakearms 24. In figure 2 is shown a cleaning element 10 from the front. The rakearms 24 are firmly connected to each other by means of support elements in the form of horizontally arranged cross springers 28 in order to achieve that both rakearms 24 move essentially parallel. A tightening device 25, consisting of diagonal rails 26 and one connection device 27 located in the centre, is arranged between the both cross springers 28. By means of adjustable elements 29, which for example may consist of rigging screws, the rakearms 24 are fixed, preferably parallel, in respect to each other. In the embodiment shown in figure 6, each of the rakearms 24 consists of two sections 11a and lib, which sections are manoeuvred by means of a chain 40, - the end of which is firmly arranged in an attachment 32, whereby it passes a first chain wheel 33, and run down through the inner part of the sections 11 to the upper part of the section lib, where the second end of the chain 40 is firmly attached. If the rakearm 24 consists of three sections 11a, lib and lie according to figure 7, the first two. sections 11a and lib are manoeuvred in the same way as the sections in figure 6, while the third section lie is manoevred by help of a second chain 41 which is fixed to an attachment 42 located on the pulley 31. The chain 41 is placed over the chain wheels 34, 35, whereby it runs through the inner parts of the main sections 11a down to the third section lie where it is fixed at its upper part. By means of the pulley 31 the rakearm sections 11a,b and c may be telescopically moved up and down along the screen 1, whereby all sections 11a, b and c in every moment are essentially proportional as much projected in respect to each other. Hereby, and by that two rakearms 24 furthermore are arranged in "tandem" and co-operate, a maximal stability during the whole work procedure is obtained. When it is practically impossible to execute a hydraulic parallel movement of the pistons of the hydralic cylinders 517, the uniform movement of the rakearms must be achieved in a mechanical way. This is solved according to the invention partly through that the above entioned cross springers 28, located between the main sections 11a, are connected by means of diagonal rails 25, and partly through that the 0 attachment of the cross springers 28 are designed in such a way that the largest possible torque resistance is achieved. In the embodiment shown in figure 8 each rakearm 24 consists of totally four sections, i.e. one further section lid has 5 been added to the three sections 11a, ,c earlier mentioned in figure 7. The pulley 31 has of course been completed by further chain wheels 36, 39 and a further chain 44 in order to control the additional section. The chain 44 is.with its one end fixed at the earlier mentioned attachment 32 which 0 is arranged at the upper end part of the support 8 and runs over two chain wheels 36, 37 arranged in the pulleys 31, and an additional chain wheel 38 arranged on the rakearm guide 8. Thereafter the chain 44 runs again up to the pulley 31, run around the chain wheel 39, which is supported in 5 bearings on the same shaft as the chain wheel 35, and down through the sections lla,b,c and is finally attached to the upper end part of the lowest sections' lid. The gear change is hereby 1:4. In combination with the gear change of 1:4 of the first pulley 19 the total effect would be a gear change in relation to said second hydraulic cylinder 17, of 1:16 for the lowest, fourth, section and the rake 14 which is attached thereon. It is, by help of a cleaning apparatus so designed, possibly to reach down to great depth in spite that the length of the cleaning apparatus 10 in its upper inactive position is short and manageable. In order to increase the clearness, figure 8 shows only the driving of the last part section. The other sections are manoeuvred in the same way as shown in the preceding figures 6 and 7. The total gear change of the above disclosed block devices in combination is 1:8, 1:12, 1:16 respectively, which therefore results in that a displacement of the rake 14 of eight, twelve, sixteen meters respectively is obtained when the rod pistons 18 of the hydraulic cylinders 17 are displaced one meter, depending on whether the number of sections is two, three or four. Among the advantages with cleaning apparatuses of this type may be mentioned that space, especially in vertical direction, is saved and that the centre of gravity of the apparatus will be located low, also when the cleaning apparatus is in its "rest position", that is when the cleaning element 10 is telescoped, which result in that the cleaning apparatus will be safe to operate and easier to install in limited spaces, when bulky reinforcements of the construction are not necessary to make. Owing to the small dimensions of the cleaning apparatus in relation to its range, the pressure from among others the water which passes by is decreased. The invention is of course not limited to the above disclosed embodiments but a number of alternative embodiments is possible within the scope of the claims. Consequently it is possible to connect still more sections.

Claims: CLAIMS 1. A cleaning apparatus for separation screens at turbine water intakes, intakes at wastewater treatment plants and the like, which cleaning apparatus includes a cleaning element which is vertically movable at least along the screen and supported by a support or on a carriage, c h a r a c t e r i z e d t h e r e b y that the cleaning element (10) includes at least two essentially parallel rakearms (24) fixedly connected to each other by means of connection elements (25-29) , that the rakearms (24) consist of telescopic movable sections (11) , the free ends of which are interconnected in pairs by cross springers (28) and that the two first sections (11a) of the rakearms (24) at the upper and lower ends are provided with diagonal rails (26) therebetween. 3. A cleaning apparatus according to claim 1, c h a r a c t e r i z e d t h e r e b y that a pulley device (31) is arranged at each rakearm 1 s (24) upper end and provided with control wires (40, 41, 44) for each section and designed to telescopically move all sections an equal distance in relation to each other, at the first section's movement in relation to at least one attachment arranged on the cleaning apparatus. 3. A cleaning apparatus according to claim 1, c h a r a c t e r i z e d t h e r e b y that the length of the diagonal rails (26) are individually adjustable by means of adjustable elements (29) . 4. A cleaning apparatus according to claims 1, 2 or 3 c h a r a c t e r i z e d t h e r e b y that the first section (11a) of the rakearms (24) consist of a square tube and that the other sections have a circular cross sections, and that the two first sections are guided by one rakearm guide (8) each.

Inventors: HANSSON HANS, HANSSON, HANS
Applicants: HANSSON HANS, HANSSON, HANS
Application year: 1983
Main classification: B07B1
IPC codes: E02B8