THRESHOLD CONSTRUCTION FOR A TILTING WEIR

Abstract: The invention concerns a threshold construction for a tilting weir where the lower edge of the weirgate (1) is connected with the threshold beam (21) via a rolling seal (11). This rolling seal (11) permits free movement of the weirgate (1). The construction of the support plate (13) makes it possible to influence the operation of the weirgate (1) by altering the profile of the lower edge (9) of the weirgate (1) and the profile of the support plate (13).

Description: Threshold construction for a tilting -weir. The invention concerns a threshold construction for a tilting weir, which seals the underside of the weirgate to the threshold beam on the bottom of the canal. The construction of the seal offers no obstructiαns to the gate movement. The construction makes it possible to influence the operation of the weirgate through the form and the support of the seal. Tilting weirs have demonstrated that they are capable of a close control of aimed weirlevels without the use of external scources of energy and electrical control equipment. A similar weir is known from the Dutch patent application I -A-8702118. Vith this type of weir water flows both under and over the weirgate. To prevent the weir operation being impaired by obstacles as transported by the stream, grates are fitted. In certain circumstances these grates are not adequate. The invention intends to supply a sealing of the lower opening of the weir, without influencing the specific characteristics of the weir while the use of grates is suspended. The invented construction which uses a flexible strip between the weirgate and the threshold construction on the bottom of the canal provides furthermore the possibility for a refinement of the control characteristics of the weir. The invention is described in conjunction with the drawings in which: Fig. 1 shows a cross section of the weir in length αf the canal. Fig. 2 shows a similar cross section of the weir in two different positions. Fig. 3 shows a protection possibility against objects thrown into the water. Fig. 4 shows a detail of the connection between the support plate and suspension. Fig. 5 shows an alternative form of the support plate and the lower edge of the weirgate in two positions. The weirgate (1) is tilting on the shaft (2). The weirgate (1) is held upright against the hydraulic press-ure with cable (3) via transmission (4) by a floating counterweight (5). The spindle construction (6) can adjust the shaft (2) vertically. In this way the weirlevel (7) can be controlled. The downstream weirlevel (8) has some influence on the correct ad ustment. The lower edge (9) has an attachment (10) for a flexible strip (11) which has its other side attached to the upper edge (12) of a support plate (13) with strengtheners (14). The support plate (13) is through bearingsleeves (15) connected to arms (16) by welding. The arms (16) are rotatably suspended from the shaft (2) of the weirgate (1). Through the bearingsleeves (15) goes shaft (17). This shaft (17) carries with bearingsleeves (18) a threshold plate (19). The threshold plate (19) is movable attached at (20) to a threshold beam (21) fixed to the bottom of the canal. A plate (23) is hinged or flexibly attached to the weirgate (1) at (24) reaching over the attachment (12) of the flexible strip (11) offers the possibility to prevent dirt accumulation on the flexible strip (11). Support plate (13) serves to support the flexible strip (11). Because the support plate (13) is suspended with arms (16) from the shaft (2) of the weirgate (1), the position of the support of the flexible strip (11) in relation to the lower edge (9) of the weirgate (1) will not change when the spindle construction (6) is used to adjust the shaft (2) of the weirgate (1). Because the flexible strip (11) unwinds between the support plate (13) and the lower edge (9), the distance between the support plate (13) and the lower edge (9) is decisive for the resultant of the hydrostatic forces exerting on the unsupported areas of the flexible strip (11). When the support plate (13) and the lower edge (9) αf the weirgate (1) are both circular farmed with axis (2) as centre, the behavior αf the flexible strip (11) is neutral. By changing the profile αf the support plate (13) and/or the lower edge (9) a progressive or regressive tilting character can. be attained. See fig. 5. ¥ith the construction, according to the invention a weir is realised where the lower edge (9) of the weirgate (1) is sealingly connected with the threshold beam (21) on the bottom αf the canal, without having any extra frictional losses. The tilting effect of the weirgate (1) is not negatively influenced, where with the help of the flexible strip (11) and the profile αf the support plate (13) and/or the profile of the lower edge (9) of the weirgate (1) makes an accurate adjustment of the required waterlevel possible.

Claims: Clains. 13 Threshold construction for a tilting weir characterised in that the lower edge (9) αf the weirgate (1) is connected with a flexible seal 05 strip (11) to the upper edge (12) of a support plate (13) which is suspended from the tilting shaft (2) and rotatably connected via a tilting threshold plate (19) to the threshold beam (21) on the bottom of the canal. 1023 Threshold construction for a tilting weir as in claim 1 characterised in that the flexible strip (11) cooperates with the support plate (13) and the lower edge (9) αf the weirgate (1) to form a rolling seal. 153] Threshold construction for a tilting weir as in claim 1 and 2 characterised in that the profile and the position of the support plate (13) and the lower edge (9) of the weirgate (1) are such that during the unwinding of the flexible strip (11) the resultant of the hydrostatic forces exerted on the unsupported section αf the flexible strip (11) and 20 tranferred to the lower edge (9) of the weirgate (1) will be enlarged, reduced or remain constant, depending on the chosen form and/or position. 4] Threshold construction for a tilting weir as in claim 1, 2 and 3 25 characterised in that the hinged or flexible attached protection plate (23) extends from the weirgate (1) to beyond the upper edge (12) of the support plate (13)

Inventors: DE WIT WILHELMUS GIJSBERTUS JO, DE WIT, WILHELMUS, GIJSBERTUS, JOSEF
Applicants: WATERSCHAP KROMME RIJN
Application year: 1990
Main classification: E02B7
IPC codes: E02B7