US3518832A - Downstream aerated gate sluice - Google Patents

Description

July 7, 1970 c5. DOLDER I DOWNSTREAM AERATED GATE SLUICB Filed July 51, 1968 AIR SIDE OF /MASONRY DAM INVENTOR.

.Dolder Guu clo Fig.2

Attorney's United States Patent 01 fice 3,518,832 DOWNSTREAM AERATED GATE SLUICE Guido Dolder, Zurich, Switzerland, assignor to Escher Wyss Limited, Zurich, Switzerland, a corporation of Switzerland Filed July 31, 1968, Ser. No. 749,041 Int. Cl. E02b 7/28 US. Cl. 61-28 6 Claims ABSTRACT OF THE DISCLOSURE A gate sluice, aerated downstream, for regulating the quantity of discharge of water in a channel, having a sluice gate movable in recesses in the side walls of said channel. The flow-separation edge at the foot of the sluice gate lies in the same plane as the edges between the side walls of the upstream channel part and the said recesses, and the upstream-directed surface of the sluice gate is situated upstream of this plane.

Background of the invention Such sluices are used for regulating for example in irrigation systems, in the regulation of the level of lakes, or in emptying a storage reservoir.

In known constructions of such sluices, their discharge side is aerated by the introduction of air into the discharge channel for preventing vibration of the sluice gate. In arrangements in which the sluices are located at the downstream end of a discharge channel, for example on the air side of a masonry dam, the part of the channel situated on the downstream side of the sluice is kept short and widened upwardly in order to bring the air as close as possible to the sluice gate.

Experience has shown that these steps are not suflicient to prevent capitation and the accompanying vibrations. The escaping water jet is whirled in such a manner that traces of cavitation occur downstream of the sluice recesses in which the sluice gate is guided. For improving these conditions, it has already been proposed not merely to widen upwardly the channel part situated downstream of the sluice gate, but also to make it larger in width. Another proposal is to widen a circular channel situated upstream of the sluice gate in front of the sluice, seen in the direction of flow, in diffusor fashion and to narrow it again immediately in front of the sluice recesses. The purpose of this nozzle-like narrowing is to allow the jet to jump across the recesses, which however is not successful in the case of partial opening of the sluice.

Summary of the invention It is the object of the present invention to improve these unsatisfactory conditions. For this purpose, a gate sluice of the known type is constructed according to the invention such that the flow-separation edge at the foot of the sluice gate lies in the same plane as the edges between the side walls of the upstream channel part and the recesses, and in that the upstream surface of the sluice gate is situated upstream of the said plane.

Brief description of the drawing Embodiment examples of the invention are represented in simplified form in the drawings, in which:

FIG. 1 shows a longitudinal section through a gate sluice along the axis of the channel,

FIG. 2 shows a section on the line IIII in FIG. 1,

FIG. 3 shows a longitudinal section through a sluice gate of another embodiment, and

FIG. 4 shows a section on the line IVIV in FIG. 3.

Corresponding parts bear the same references in all the figures.

Description of the preferred embodiments The gate sluice shown in FIGS. 1 and 2 has a sluice gate 3, located between the upstream channel part 1 and the downstream channel part 2. The sluice gate 3 is guided in recesses 4 of the gate guide 5 by means of flanks 6 projecting into the said recesses. The bearing surfaces of the sluice gate 3 in the recesses 4, that is to say, those parts of the downstream-directed surfaces of the flanks 6 which transmit the force of the operating water on the sluice gate 3 to the gate guide 5 are shown at 7. The part 15 of the gate guide 5 situated upstream of the recesses 4 forms a part the upstream walls 11 of the upstream channel part 1. These side walls 11, 15 of the upstream channel part 1 form edges 8 with the recesses 4. The part 25 of the gate guide 5 situated downstream of the said edges 8 forms a part of the downstream walls 22 of the downstream channel part. The upstream surface of the sluice gate 3 situated within the cross-section of the upstream channel part 1 is shown at 9. At the foot of the sluice gate 3 is the flow-separation edge 10. The upper and lower boundaries of the flow are shown at X and Y.

As shown by the drawings, the flowseparation edge 10 is located at the foot of the sluice gate 3 and, according to the invention, in the same plane 88 as the edges 8, and the upstream surface 9 of the sluice gate 3 is situated, according to the invention, upstream of the said plane 88. In a particular development of the subject of the invention, the distance in the direction of the channel axis between the edges 8 (or the plane 88) and the bearing surfaces 7 of the sluice gate 3 is kept as short as possible and is determined by the calculated strength of the flanks 6 of the sluice gate 3 which project into the recesses 4. The downstream surface 12 of the sluice gate 3 lies in the plane of the bearing surfaces 7.

The arrangement of a gate sluice according to the invention is not only structually desirable, but is also accompanied by appreciable hydraulic advantages. The slight axial extent of the flanks 6 and recesses 4 gives the same slight axial distance between the flow-separating edge 10 and the downstream edges 16 of the recesses, since the flow-separating edge 10 lies in the same plane 88 as the edges 8. In this way, the lateral edge zones of the jet determined by the sluice gate jump across the recesses 4 in any position of the sluice gate, and are not caught by the said recesses, so that eddying in the recesses and consequent erosion and cavitation do not occur.

The displacement of the flow-separation edge 10 from the upstream surface 9 of the sluice gate 3 downstream into the vicinity of the plane 88 also permits streamlined construction of the foot of the sluice gate 3. The more streamlined is the transition from the perpendicular upstream surface 9 to the flow-separation edge 10, the smaller is the lateral spread of the jet downstream thereof. A streamlined construction of the foot of the sluice gate also prevents cavitation and vibration thereof. The shifting of the flow-separating edge 10 as far as possible from the upstream surface 9 of the sluice gate provides the necessary and sufficient distance in the axial direction of the channel for a streamlined construction of the foot of the sluice gate.

The bearing surfaces 7 of the flanks 6 of the sluice gate 3 in the recesses 4 are located, with reference to the channel axis, outside fictitious planes 13, which pass through the edges 8 and make an angle at of 45 to the channel axis on the downstream side. The channel-side boundary surfaces 14 of the downstream part 25 of the gate guide 5 are situated in these planes 13. Due to this step, the plane 88, in which lie the flow-separation edge 10 and the edges 8, and from which the downstream channel part 2 starts, contains the clearly defined smallest cross-section of flow, and in particular, the downstream edges 16 of the recesses 4 lie father from the channel axis than the upstream edges 8 of the recesses. These steps additionally contribute in ensuring that the jet of operational water jumps across the recesses 4, and that jet disturbances in the lateral edge zones will be prevented. Model experiments which have been made have shown that for ensuring control of the jet in all positions of the sluice gate, a downstream inclination of the plane 13 of at least 45 is necessary. Under particularly unfavourable conditions, such as for instance high water velocity or greater axial extent of the flanks 6 due to considerations of strength, the angle of inclination a must be increased. Of course, the boundary surfaces 14 of the downstream part 25 of the gate guide may also lie outside the planes 13, referred to the channel axis.

The channel bottom of the gate sluice shown has an upstream part 111 extending in the direction of flow up to the plane of the bearing surfaces 7. At this place, the channel bottom has a stepped offset 77 away from the channel axis, and the downstream channel bottom part 222 extends at a greater distance from the channel axis than the upstream channel bottom part 111. This step prevents the unavoidable downward and laterally directed, fan-shaped edge zones of the jet rebounding on a channel bottom extending downstream of the sluice gate at the same level as upstream and being partly thrown back against the boundary surfaces 14 of the gate guides 5 and so producing disturbances in the recesses 4. The offset of the channel bottom 222 from the plane of the bearing surfaces 7 of the sluice gate 3 away from the channel centre enables the edge zones of the jet to extend downstream in well-aerated zones. The channel-side surfaces of the side walls 22 situated downstream of the downstream part 25 of the gate guide 5 are also situated in the planes 13; of course, referred to the channel axis, they could also be situated outside this plane 13, or further downstream they could also be situated within the plane again for forming the walls of a channel or conduit with free water level.

Due to the steps according to the invention, a gate sluice is provided, which prevents cavitation and vibration in all positions of the gate by the simplest means.

The gate sluice shown with the downstream walls 22 is constructed for connection to a downstream channel part 2 of a definite length. It is however also possible of course to allow the gate sluice shown to terminate downstream with the downstream part 25 of the gate guide 5, for example when arranged on the said side of a masonry dam. In such a case, the channel bottom may terminate with its upstream Part 11, that is to say, in the r The gate sluice shown in FIG. 3 and 4, in contrast to 5 that shown in FIGS. 1 and 2, instead of the transition formed at the foot of the sluice gate 3 of the upstream surface 9 of the sluice gate at right angles to the channel axis being produced by chamfering to the flow-separation edge '10, has a rounding as far as the downstream surface 12. The channel-side surfaces of the downstream walls 422 do not lie in the planes 13, referred to the channel axis, but outside the said planes.

I claim:

1. A gate sluice, having a bottom and an upper wall and side walls confining an upstream channel part and a downstream channel part, the latter being open to the atmosphere, said side walls having essentially vertical recesses between both said channel parts for guiding a vertically movable sluice gate with a flow-separating edge at its bottom, in which said sluice gate has lateral flanks projecting into said recesses, said flanks extending in the direction of the channel axis for a distance less than the distance between the. upstream-directed and the downstream-directed surfaces of said sluice gate, in which said flow-separating edge at the foot of said sluice gate lies in the same plane as the edges between said side walls of said upper channel part and said recesses, and in which said upstream-directed surface of said sluice gate is situated upstream of said plane.

2. A gate sluice as defined in claim 1, in which the upstream-directed surfaces of said recesses are situated, referred to the channel axis, outside fictitious planes, which pass through said edges between said side walls of said upper channel part and said recesses, and which downstream are inclined at an angle of at least 45 to the channel axis.

3. A gate sluice as defined in claim 2, in which the channel-side surfaces of said side walls of said downstream channel part are situated at least as far from the channel axis as are said fictitious planes.

4. A gate sluice as defined in claim 1, in which the distance for which said flanks of said sluice gate extend in the direction of the channel axis is as short as possible, and is determined by the calculated strength of the flanks.

5. A gate sluice as defined in claim 4, in which the downstream-directed surface of said sluice gate lies in the plane of the upstream-directed surfaces of the recesses into which said flanks of said sluice gate project.

l6. A gate sluice as defined in claim 1, in which the channel bottom, viewed in the direction of flow of the operational water, has in the plane of the upstreamdirected surfaces of said recesses a stepped offset away from the channel axis, and in which the downstream channel bottom part extends farther from the channel axis than the upstream channel bottom part does.

References Cited UNITED STATES PATENTS 769,968 9/ 1904 Warren 61-28 988,777 4/ 1911 Hedrick 6128 1,450,989 4/1923 Schuster 6128 1,528,421 3/1925 Hayes 6128 X 2,056,679 10/ 1936 Lehman 61-28 PETER M. CAUN, Primary Examiner

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