The subject invention concerns an improved separating device for collection and removal of solid particles and objects present in running water, said separating device being positioned in a channel through which said running water flows and having a stand supporting a separating unit arranged in a position of inclination obliquely rearwards, as seen in the direction of flow of the water, and comprising upended separating grid bars positioned side by side, of which fixed bars alternate with mobile bars, said bars having collection and removal means on their edges turned towards the direction of flow of the water, the fixed separating grid bars being fixedly connected to the stand whereas the mobile separating grid bars are movably connected thereto and arranged to be actuated by a drive unit in order to carry the solid particles and objects step by step upwards by means of their collection and removal means, out of the running water and along the collection and removal means of the fixed separating grid bars, up to an outlet from which the solid particles and objects thus collected are removed. In one prior-art separating grid of the kind outlined above, the collection and removal means of the fixed and mobile separating grid bars have a step-like configuration along the entire length of the bars, and the mobile separating grid bars are arranged to be actuated by a drive unit imparting to the mobile separating grid bars a closed path of movement in the plane of the grid bars, the vertical component of movement of which somewhat exceeds the height of the steps of the fixed grid bars. In the prior-art separating grid, the mobile separating grid bars thus have a parallel displacement pattern similar to that of a draw-bar, i.e. all parts of the grid bars follow an identical circular path.

Because the lower ends of the mobile grid bars move vertically upwards and downwards to the same extent as forwards and backwards, it is very difficult to provide efficient sealing at the lower ends, particularly if one wishes to build a machine wherein the inter-bar spacing is smaller than the thickness of the separating grid bars. On account of the comparatively high velocity of the running water, solid particles and objects therefore will penetrate into the gaps between the fixed grid bars, which bars are left exposed as the lower ends of the mobile grid bars move vertically upwards with respect to said gaps.

The particles and objects that will fall through the grid entirely will be entrained by the running water, resulting in incomplete separation, with the result that further cleaning of the water will be required and/or that problems will be encountered in subsequent water- cleaning steps, with ensuing increase of costs and work. The particles and objects that are so large, heavy, and/or hard that they are caught in the gaps between the fixed separating grid bars are hit by the lower edges of the mobile bars as the latter descend vertically into said gaps. The result is that these particles and objects, already stuck, will be forced further down into the gaps and finally clog the latter to a smaller or larger extent, or else, before this happens, the lower ends of the mobile grid bars may already have been deformed or made inopera¬ tive. Even if an increase of the grid bar dimensions were to make the bars more apt to withstand the stress to which they are exposed, the resistance would sooner or later reach such levels that the drive unit would no longer be capable of driving the mobile grid bars and come to a standstill, unless overload on the unit has already damaged it.

Irrespective of whether the mobile grid bars and the drive unit including the motion transmission mechanism associated therewith were to support the stress, the gaps between the fixed grid bars must be cleaned manually or

3 with the aid of special equipment, of stuck or jamming particles and objects. This is a tedious and work- consuming job, in addition causing a more or less lengthy and serious shut-down. The situation is further aggravated if the grid bars or other components are damaged to such an extent that repairs and/or replacement of parts become necessary.

The purpose of the invention is to provide a separating device or grid of the kind defined in the introductory part wherein the drawbacks outlined in the aforegoing have been eliminated.

This purpose is achieved in accordance with the invention in that the mobile grid bars are connected at their upper ends to the drive unit while the lower grid bar ends are guided by the stand, and in that the drive unit imparts to the mobile grid bars a movement which at the upper ends thereof follows a closed path but which in a direction towards their lower ends follows successively and increasingly flattened ellipsical paths, and which at the lower grid bar ends follows an essentially rectilinear to-and-fro path.

The invention will be described in closer detail in the following with reference to the accompanying drawings illustrating one at the moment particularly preferred although not restrictive embodiment. In the drawings:

Fig. 1 is a schematical view from the s.de with some parts broken away, of a separating grid in accordance with the invention positioned in a channel of running water.

Fig. 2 illustrates the separating grid in accordance with Fig. 1 in a front view as seen in the direction of arrow A.

Figs. 3 - 5 illustrate schematically in lateral and partly sectionalized views detail components of the areas marked B, C, and D, respectively, in Fig. 1. Figs. 6A-9B illustrate schematically one cycle of the movement performed by the mobile grid bars incorporated in the separating grid in accordance with the invention.

The separating grid designated generally by numeral 1 has for its purpose to collect and transport solid particles and objects 4 present in running water 2 flowing through a channel 3. The particles and objects 4 are dis- charged onto a conveyor 5 or similar device of suitable construction for removal.

The separating grid 1 has a stand 9 essentially consisting of side plates 6, end plates 7, and frame profile members 8. The side plates 6, the end plates 7 and advantageously also the frame profile members 8, preferably are made from a stainless material, such as stainless steel or some other material able to resist the effects of the running water 2 and its contents.

The side plates 6 of the stand 9 form the lateral delimiting and protecting walls of the separating grid 1 and they are configured in such a manner as to taper towards the lower end of the grid 1, which end is submerged in the running water 2, whereas the end plates 7 delimit the upper rear wall of the separating grid 1. Intermediate its side plates 6 the stand 9 supports a separating unit, generally designated by 10, which like the stand 9 assumes an obliquely upwards and rearwards tilted position, as seen in the direction of flow E of the running water 2. The separating unit 10 comprises a number of fixed and mobile grid bars positioned side by side, the fixed grid bars 11 alternating with the mobile bars 12. The grid bars are upended and like the components making up the stand 9 they preferably are made from stainless steel or other water-resistant material. In a manner to be described in closer detail in the following, the fixed grid bars 11 are secured to the stand 9 whereas in a manner _.._kewise to be described in closer detail further on the mobile grid bars 12 are movably secured to the stand. The number of fixed and mobile grid bars 11, 12 may be varied according to the desired width of the separating grid 1, and when the grids are very large, the grid

bars may be arranged into one or several groups.

As seen from the side, the fixed as well as the mobile grid bars 11, 12 have a slightly depending arcuate configuration forming an angle to the horizontal plane that increases progressively from the bottom and upwards. On their upper edges turned towards the direction of flow E of the water 2 the bars are provided with collection and removal means 13. These means 13 are in the shape of depressions 14 and peaks 15 formed alternately in succes- sion along essentially the entire length of the grid bars 11, 12, the depressions becoming deeper and the peaks higher and more pointed, as seen in the direction from the lower ends 16 of the grid bars 11, 12 to their upper ends 17. In other words, the depressions 14 and the peaks 15 are shallow and low, respectively, at the lower ends 16, in which area their configuration resembles that of small waves, and become increasingly more pronounced in the direction towards the upper grid bar ends 17, in which area they have a step-like configuration. The mobile grid bars 12 of the collection and removal means 13 serve the purpose of carrying, when actuated by a drive unit 18 to be described in more detail in the following, the solid particles and objects 4 step by step upwards, out of the running water 2 and along the fixed grid bars 11, the latter being formed with identical collection and removal means 13, up to a discharge 19 positioned on the lower face of the upper end of the stand 9, upstreams of the upper ends 17 of the grid bars 11, 12. From this discharge 19, the particles and the objects 4 are transferred onto the conveyor 5 or similar trans¬ portation means for removal.

To impart the desired movement to the mobile grid bars 12 the latter are connected to the drive unit 18 in the area of their upper ends 17 and in the area of their lower ends 16 they are guided by the stand 9.

More precisely, in the area of their upper ends 17 the mobile grid bars 12 are rigidly mounted on an upper movable cross beam 20, see Figs. 1 and 5, in such a manner as to be individually removable. In accordance with the embodiment illustrated, the cross beam 20 is shaped as a box girder which is positioned underneath the mobile grid bars 12 and have upper and front recesses 21, 22 in which are removably received rearwardly and downwardly directed double hooks 23 formed on the mobile grid bars 12. In accordance with the embodiment illustrated, the double hooks 23 are secured in the recesses 21, 22 and conse¬ quently to the cross beam 20 in that one of the double hooks is wedged in position by means of a profiled wedge 24 the tightening of which is effected by means of a tightening bolt 25.

In the area of their lower ends 16, the mobile grid bars 12 are more precisely secured to a lower cross piece 26, see Figs. 1 and 3, so as to be individually removable. The cross piece 26 which is mounted in the stand 9 for controlled movements therein, extends between the side plates 6 and is formed with downwardly directed guide profile members 27 which are secured by fastening means, not shown, to the short ends of the plates or made integral therewith. Each one of said profile members 27 is formed with a longitudinal groove 28 in which a guide rail 30 of metal or other suitable material is mounted for controlled sliding movement therein. The rails 30 are secured to the stand by means of fasteners, for instance in the shape of bolts 29. The cross piece 26 the movements of which thus are controlled as indicated, preferably is in the form of a shuttle plate of a primarily stainless material or other material that is resistant to the running water 2. The shuttle plate 26 is formed with upper recesses 31 in which downwardly and forwardly directed hooks formed at the lower ends 16 of the mobile grid bars are removably received. The hooks 32 are fastened in the recesses 31 by

7 means of a covering plate 33, preferably of a plastics or other, similar material. The covering plate 33 is attached to the upper face of the shuttle plate 26 in some suitable manner, for instance by means of fasteners, such as screws or bolts, not shown in detail. A front length¬ wise edge 34 of the covering plate 33 penetrates into grooves 35 formed in the lower ends 16 of the mobile grid bars 12 so as to secure the hooks 32 in engagement with the recesses 31. In the area of their lower and upper ends 16, 17, the fixed grid bars 11 also are individually removably mounted on an upper and a lower fixed cross beam 36, see Figs. 1 and 2, said fixed cross beams 36, which also form two of the frame profile members 8 of the stand 9, being in the shape of box girders. The box girders present front recesses 37 in which downwardly and rearwardly directed hooks 38 formed on the fixed grid bars 11 in the area of their lower and upper ends 16, 17 are removably received. The hooks 38 are secured in position in the recesses 37 with the aid of profiled wedges 39 clamping the hooks 38 against an inner face of the box girders with the aid of a tightening bolt or set bolt 40 or equivalent means.

The drive unit 18 referred to previously serves to impart a particular movement to the mobile grid bars 12. This movement, see Figs. 3 and 6A-9B, follows a closed, essentially circular path in the area of the upper ends 17 of the mobile grid bars 12 and in the direction towards the lower ends 16 of the mobile grid bars the movement successively follows more and more flattened or com- pressed, elliptical paths and at their lower ends 16 the grid bar movement is an essentially rectilinear to and fro movemen .

In order to produce this motion of the mobile grid bars 12, the drive unit 18 comprises a drive motor 41 which is mounted at the upper end of the stand 9, see Figs. 1 and 2, and a gear bo:: 42 mounted thereon, comprising two coaxial and oppositely directed output

drive shafts 43. The drive shafts 43 are rotationally mounted in bearings 44 on the side plates 6 of the stand 9 and extend through said plates. Externally of the side plates 6 the drive shafts 43 actuate their respective one of two identical eccentric mechanisms 45 which via their individual follower means 46 associated with the upper mobile cross beam 20, impart the movement pattern referre to above to the mobile grid bars 12.

Each eccentric mechanism 45 has an eccentric arm 47, see Figs. 1, 2 and 6A-9B, at one end of which is formed a recess 48 for attachment of the arm to the free end of th asociated output drive shaft 43, and presenting at its opposite end an eccentric pin 49. By means of a support 5 corresponding to the support 44 mounting the output drive shaft 43, the eccentric pin 49 is supported in the follower means 46 at the upper end thereof, the lower end of said follower means being attached to the upper mobile cross beam 20.

In accordance with the embodiment illustrated, each follower means 46 preferably is composed of two parts 51 and 52. Both parts 51, 52 preferably are made from sheet metal and one of them 51, serves to mount the eccentric pin 49 whereas the other one, 52, is securely connected to the upper mobile cross beam 20, for instance by being welded thereto. The parts 51, 52 are interconnected by means of a fastener 53 in the form of e.g. bolts which may be untightened and which after untightening allow the parts 51, 52 to be moved with respect to one another and consequently allow adjustment of the mutual positions of the fixed and mobile grid bars 11, 12 in order to provide the most efficient collection and removal of the solid particles and objects 4.

Figs. 6A - 9B illustrate schematically one cycle of the movement of the mobile grid bars 21 in relation to the fixed grid bars 11 in various angular positions of the eccentric arm 47.

In Figs. 6A and 6B, the mobile grid bars 12 are in their "home position", i.e. in their lowermost position corresponding to the position in Figs. 1 and 2 in which position the fixed and mobile grid bars and their respective depressions 14 and peaks 15 forming the collection and removal means 13, are in perfect regis¬ tration with each other, side by side.

In Figs. 7A and 7B, the mobile grid bars 12 are in a lifting phase wherein they lift and transfer, by one step, the solid particles and objects 4 resting on their collection and removal means 13, onto the subsequent collection and removal means 13 on the fixed grid bars.

In Figs. 8A and 8B, the mobile grid bars 12 have reached their delivery phase, wherein they assume their uppermost position and deliver the particles and objects 4 onto the fixed grid bars 11.

In Figs. 9A and 9B, finally, the mobile grid bars 12 are in their return phase towards "home position", wherein the collection and removal means 13 of the mobile grid bars are positioned below the corresponding means 13 on the fixed grid bars 11 in order not to interfere with the partioles and solid objects resting thereon.

The invention must not be considered to be limited to the pr-eferred embodiment described above and illustrated in the drawings but could be modified in a variety of ways within the scope of the appended claims.

For example, the movement which in the area of the upper ends 17 of the mobile grid bars 12 follows a closed, essentially circular path, could instead follow a path of a different configuration, for instance a more or less elliptical or a rectangular path, etcetera.