MECHANICAL AUTOMATIC TILTING WEIR WITH SELF-ADJUSTING LOWERING OF THE WEIR-LEVEL DURING LARGER DISCHARGES

Abstract: The invention concerns a weir with an on a horizontal axis tilting gate (1). The control is automatic and completely mechanical and operates without an external source of energy. The control uses a float/counterweight (4) placed in an enclosure (5) which is in connection with the upstream level. The float/counterweight (4) is connected to the equator (13) on the gate (1) by a transmission mechanism consisting of (7), (10) and (11). The float/counterweight (4) is in balance with the hydraulic forces on the gate (1). The tilting axis is placed about 0.4 of the height of the gate (1) from the underside. During large discharges the gate (1) tilts further to increase the flow. This enables the weir to establish within shorter time the desired level. A horizontal submerged grate (15) prevents choking of the weir. The gate (1) can be adjusted vertically by a leadscrew (16) to set the weir level. A threshold-beam (20) is connected to guidings (17) to keep the gate-equilibrium by every adjusted height.

Description: _!_ Mechanical automatic tilting weir with, selfadjusting lowering of the weir-level during larger discharges. The invention concerns an an a horizontal axis tilting weirgate (1) 05 that maintains mechanically a preset weirlevel entirely automatic, but can adjusted thus that in times of a larger flow of water even a lowering of the preset weirlevel is obtained. ' The operation is based on a balanced equilibrium between the hydraulic . ' forces exercising on the gate (1) and the resisting forces of 1 10 or 2 floats/counterweights (4). The horizontal pivot (2) is mounted sligtly below the centre of the gate (1). The forces are transmitted by means of an adjustable connection (13), a cable (14), an adjustable drum (il), a disk (10 ' welded on shaft (7) and a cable (6). ,15 A grate (15) prevents floating treebranches and waterplants to get in between the underside of the gate (1) and the threshold-beam (20). Gate (1) and grate (15) are hanging in a spindle- or lifting structure (16) which permits the adjustment of different weirlevels. 20 Host of the presently used weirs, capable of complete, automatic. holding of the desired weirlevel, all need a mechanism electrically or hydraulically driven. The disadvantage of these weirs is that they are costly to install, especially when there is no electricity available in the vincinity. 25 In the past there have been weirs designed which have an automatic level-control based on the hydraulic forces exercised on tie gate with or without counterweights. A number of these conceptions is, like the present invention, based upon the principle where the gate rotates on a horizontal axis, placed 30 just below the centre αf the gate. See ior this the French patents nr. 430.623, 645.345 and 81 04753, the German patents nr. 53732 and 162443 and the American patent nr. 2.966.777. The concepts of these patents have all at least minimal 2 of the named important disadvantages: 35 i) a constant weirlevei-reguiation with comparatively small deviations is not possible; 2) adjusting of a variable weirlevel is not possible; 3) by the stream transported treebranches and such can hook on the underside of the gate , which prevents a good functioning of the gate. A separate vertical grate placed before the weir could reduce this disadvantage, but introduces another important disadvantage of the repeated silting of the grate by waterplants and the like which stagnates the discharge. By other designs the original principle is a rotational axis at the underside of the gate or above the waterlevel. These have also the same ' disadvantages as above mentioned under point 1 and 2, while moreover a relatively large and heavy float/counterweight is required, which makes the whole weir construction expensive. The subject invention (see FIG. 1 and FIG. 2) is free from the above mentioned disadvantages and building is considerable more pro itably than the above named modern electrically controlled weirs. The weir consists of five major parts, namely a tiltable weirgate (1), one or two floats/counterweights (4), a leadscrew or lifting construction (16), a grate (15) and a threshold-beam (20). The gate CD turns with a horizontal fixed shaft (2) in a bearing (3) placed on both sides next to the gate (1) and is vertically adjustable. This horizontal shaft (2) is mounted about 0.4 αf the height of the gate measured from the underside. Presumed is that the weirlevel is equal or slightly higher than the upperside of the gate ' (l). These assumptions results in that the gate (1), only by the hydraulic forces, is nearly in equilibrium. The second essential part of the invention is the use of 1 or 2 floats/counterweights (4) upstream of the weir and near the gate (1). These floating counterweights (4) are hanging in an enclosure (5) by a steel cable (6) to a horizontal shaft (7), which is positioned above the waterlevel. This shaft rotates on both sides in a bearing <δ) mounted in the side of the enclosure (5) in the nearness of the gate (1). In the same side is an opening (9> placed amply below weirlevel which forseeε that the waterlevel in the enclosure C5) is always equal to the level in the canal. Instead of these openings (9) tα the water near the gate (1) it is also possible to connect the enclosures (5) by way of a tube, well below the watersurface, with a on a certain distance coint of the upstream canal. The level in the enclosures (5) correspondents then with the level on that point. On this way it is possible to influence the control of the weir on distance. On the of shaft (7) is welded a fixed disk (10) and is mounted a rotatable drum (11) with an extending rim. The drum (11) is clamped by the rim with some bolts and clamping plates (12) to the disk (10) and may be adjusted at wish. Another solution is a worm and wormwheel transmission. Disk (10) and drum (11) are intended to adjust the correct -counterweight after changing the vertical position of the gate (1) with the leadscrew construction (16). The gate (1) is indirectly connected to the drum (11). This fixing structure (13) can consist of a adjustable equator, that the forces from the drum (11) distribute equally to both ends of the gate (1), or can consist of an adjustable construction on one side of the gate. Floats/counterweights (4) and gate (1) are thus connected indirectly, while the gate (1) is kept closed by the floating and at the same time hanging floats/counterweights (4), until the level of the water is rising. A slight rising of the waterlevel results in two effects: a, the downward force executed by the floats/counterweights reduces when the water level rises as result of the increase of the upward force of the water executed on the floats/counterweights, and b. as result of the increase of the hydraulic forces on the gate, causes a larger momentum in reference to the turning point in bearing (3), which causes the gate (1) to tilt forward. These are 2 influences that support each other to have the gate (1) react when the waterlevel rises. To have a sufficient tilting of the gate (1) when a slight rising of the level occurs there is an enlarging transmission of floats/counterweights (4) to the gate incorporated by using the relative large diameter of the drum (11) and the small diameter of the shaft (7). This is possible by the chosen point of view that the gate is nearly -in eqilibrium as result of the hydraulic forces. Even the choice of a relative small and light float/counterweight (4) is in this way possible. As the gate tilts the changing of the hydraulic forces on the gate causes a increase of momentum, which results in further tilting, This tilting of the gate (1), causing the floats/counterweights (4) to lift out of the water, goes on until these floats/counterweights 4) produce sufficient counterforce and find a new equilibrium. This results in an automatic temporary regulating lowering of the weirlevel at times of larger discharge of water. This results in an increased fall in the upstream canal and as consequence a larger capacity to discharge. This automatic regulation of lowering of the weirlevel can be adjusted by changing of the adjustment of the equator (13) on the gate (1). As the discharge decreases, hydraulic forces - and at the same time with them the momentum will decrease, causing the gate to close gradual by the influence of the floats/counterweights (4), in response of the speed of decrease of the water discharge. Because of the tilting construction of the gate (1) there will also start a stream of water below the gate CD when the gate CD tilts. Floating dirt like branches could attach themselves to the gate CD, which can prevent the closure when discharge decreases. To overcome this problem a grate C15) that is almost horizontal, below the waterlevel and near the gate CD vertical movable, placed about the level of the turning point of the gate CD . The almost horizontal placing and the direction of the grate-bars parallel to the direction of the stream have the result that the grate (15) hardly silts with plants and other suspended dirt; the most of the dirt is carried along over the gate CD by the stream. For the adjustment of different summer-, winter-, and intermediate-weirlevels there is a leadscrew construction (16) with guidings C17) provided on and in the sides of the weirconstruction, which has a central operating handle. Every guiding C17) incorporates the bearing C3), permitting the gate CD to tilt, a fixed bolt C18) that bears the grate C15) and a fixed bolt C19) to which the threshold-beam C20) is fixed by means of a connection C21). This threshold C20) rotates by a hinge C22) when the guiding (17) is moved up- or downward by means of the leadscrew construction C16), This results in no changing of the distance from the striking point C23)-to the tilting axis of the gate CD. This is necessary to keep the starting equilibrium. The hinge C22) itself is connected to the weirthreshold C24). On both sides of the flat gate CD is " a plate C25) mounted, moving with the gate (1), and a plate (26) which is mounted on the sides of the fixed weir-structure. The cleft between the plates C25) and C26) are sealed with rubber profile. Instead of a threshold-beam with a hinge there is also an other design possible. Csee FIG. 3). A plate C27) is welded to the guidings (17). Between these 2 plates is mounted the threshold-beam (28). When the guidings (17) by means of the leadscrew C16) are moved up and down, the threshold-beam (28) is sliding in front of the weirthreshold (29). With this solution the gate CD will keep the same angle of incidence when the weirlevel is changed. To ease the adjustment of the position of the gate (1) there is a beam (30) provided on the weirεtructure on which a pin (3D is mounted. With the help of a flat steel bar, provided with a handle, several holes and a hook on the bαttomside, is it possible to arrest the gate (1) while adjustments are made. To make adjustments of disk (10) and drum (11) possible, there is a wide concrete gangway (32) provided. If the down-stream level can be very different, it is necessary to build a simple, but wide threshold-beam construction (33), if necessary provided with detachable beams (34) .

Claims: Clai s Claim 1: Weir with a gate-adjustment depending of the waterdischarge provided with a gate that tilts about a horizontal axis characterised in that the tilting point is slightly underneath the centre of the gate and that the inclination of the gate CD is determined by the equilibrium between the hydraulic pressure on the gate CD and the by way of a transmission connected floatCs)/counterweightCs) C4), which are placed in an enclosure C5) that is in open connection with the ' weirlevel. Claim 2: Veir according to claim 1 characterised in that the transmission between float(s)/counterweight(s) (4) and gate (1) is realised by means of cablewheels with a difference in diameter between them which causes to enlarge the movement of the gate CD compared with the movement of the floatCs) C4). Claim 3: Veir according to claim 1 and 2 characterised in that the seizing point of the adjustment cable C14) to equator C13) is placed above and outside the plane of the gate CD and incorporates an adjustment possibility. Claim 4: Veir according to claim 1, 2 and 3 characterised in that the threshold sealing is realised ' by means of a threshold beam C20) that rotates with a hinge C22) and is connected to the vertical movable guidings C17) of the gate CD, Claim 5: Veir according claim 1 to 4 characterised in that an almost horizontal grate (15) is provided that reaches near the gate CD and is connected to the vertical movable guidings C17? of the gate CD. Claim 6: Veir according to claim 1 to 5 characterised in that the weirgate CD is vertical adjustable. Claim 7: Veir according to claim 1 to 6 characterised in that the control of the weir operates independent of external scources of energy.

Inventors: DE WIT W G J, DE WIT, W., G., J.
Applicants: WATERSCHAP KROMME RIJN
Application year: 1988
Main classification: E02B7
IPC codes: E02B7