Hose weir

Description

[0001] The invention relates to a hose weir with a hose which is attached to a weir bottom and can be filled with water as a dam and with a flexible membrane sheet which rests on the hose and which is held tensile-resistant with its upstream end against the hose and which is anchored with its downstream end at a distance from the hose to the weir bottom.

[0002] The dam body of hose weirs used in flowing waters is formed by a water-fillable hose made of a flexible membrane, which is clamped to the weir bottom and to the lateral weir cheeks or weir piers using clamping rails to ensure a liquid-tight seal. The projected head determines the dimensions of the hose and requires a fixed internal pressure within the hose. When the weir crest is above water, the cross-sectional shape of the hose then determines the flow path of the overflow jet (DE 101 31 873 A1, DE 10 2007 041 611 B3). The overflow jet impacts the weir bottom with a significant flow component perpendicular to the weir bottom, losing a large portion of its kinetic energy, which is usually desirable to prevent erosion on the downstream side.

[0003] However, this energy loss is disadvantageous when using rubber weirs to provide an overwater jet whose kinetic energy is to be used, as is the case, for example, in ejector power plants, where the overwater is additionally accelerated along an ejector ramp ending above the draft tube outlet of a turbine, in order to then combine with the driving water to increase the usable head (AT 519 155 B1).

[0004] To generate standing waves in a flowing water, it is known (WO 2004 / 076779 A1) to arrange a water-fillable hose body downstream of a guide ramp sloping downstream from a hose weir, on which the standing wave builds up. A flexible membrane sheet is anchored tensile-resistant upstream of this hose body, resting with its free end on the hose body and having a comparatively high dead weight. As the hose body is filled, the membrane sheet is raised and lowered. Due to the high dead weight of the membrane sheet, the susceptibility of the hose body to vibration can be reduced, especially when the hose body is empty or only partially filled.Since this membrane web influences the flow conditions on the upstream side of the hose body, but not on the downstream side, such a membrane web cannot contribute to using the kinetic energy of the overflow jet of a hose weir on the downstream side with as little loss as possible.

[0005] In order to reduce the environmental impact of noise on inflatable weirs, particularly in ice-covered rivers, it has already been proposed (JP S57-137512 A) to arrange another, lower hose body downstream of the hose weir forming the dam body and to guide a flexible membrane web over these two hose bodies, the upstream end of which is anchored upstream of the dam body and the downstream end of which is anchored to the weir bottom at a distance from the lower hose body, so that the overflow water is fed to the downstream side in two stages along the flexible membrane web with a corresponding reduction in kinetic energy.

[0006] To reduce noise, it is also known (JP S60-112913 A) to attach a rigid plate to the outlet side of the hose body. The downstream end of the plate rests loosely on the weir bottom and guides the overflow water along a predetermined flow path from the hose body to the weir bottom. To minimize deflection of the plate due to the overflow, the plate is provided with openings for the overflow water, so that the space below the plate is filled with water, which can flow away between the weir bottom and the end of the plate resting loosely on the weir bottom.

[0007] In order to create a guide surface for the water flow of a wave-riding facility that initially rises and then falls in the direction of flow, it is also known (EP 0 547 117 B1) to stretch a flexible membrane sheet over several water-fillable hose bodies that initially increase in diameter and then decrease in diameter. By applying appropriate pressure to the hose bodies, the wave-riding surface can thus be additionally moved in a wave-like manner.

[0008] Finally, it is known (FR 2 565 271 A1) that a water-fillable hose is not attached to the weir base, but rather placed within an elastic sheath attached to the weir base, which holds the inflatable hose in place. The elasticity of the sheath is necessary to allow the hose to be filled from an initial position in which the sheath holds the hose in a folded, empty position. On the other hand, the elastic sheath requires a protective cover, which is anchored to the sheath in the weir base only upstream.

[0009] The known guide devices for the overflow water flowing from the body of a rubber weir to the downstream side, which serve various purposes, always involve a reduction in the kinetic energy of the overflow jet. The invention is therefore based on the object of designing a rubber weir using structural means so that the kinetic energy of the overflow jet is available on the downstream side with as little loss as possible.

[0010] Starting from a hose weir of the type described above, the invention solves the stated problem in that the membrane web is freely guided between an upstream system on the hose and the downstream anchoring and forms a flexible guide ramp for the overflow jet and in that the downstream end of the membrane web is connected to a tensioning device.

[0011] Due to the free sag of the flexible membrane sheet between the upstream system on the hose and its downstream anchoring, a membrane sheet course along a cable curve is established, even with varying but constant loads from the overflow water along the flow path. With an appropriate distance between the downstream anchoring and the hose and an adapted sheet length, this ensures a flexible guide ramp for a largely laminar flow of the overflow jet and thus low energy losses in the area of the flow transition from the flexible guide ramp to an adjacent weir base, for example a horizontal base plate or an inclined weir ramp. In order to create a largely loss-free flow transition from the guide ramp formed by the flexible membrane sheet to the adjacent weir base, a streamlined, as smooth as possible transition must be ensured.This is advantageously achieved by connecting the downstream end of the membrane sheet to a tensioning device, with the aid of which an essentially tangential connection of the membrane sheet to the continuing weir base can be adjusted.

[0012] If the tensioning device includes a weight roller mounted in a loop guide at the downstream end of the membrane sheet, a self-regulating tensile stress independent of external conditions can be applied to the membrane sheet, thus adjusting the sag depending on the current load from the overflow water. Another possible design for a tensioning device is to provide a tensioning shaft that supports the downstream end of the membrane sheet and is actuated accordingly to determine the sag of the membrane sheet.

[0013] The drawing shows an example of the subject matter of the invention. Fig. 1 a rubber dam according to the invention in a schematic, partly torn-open plan view, Fig. 2 this rubber dam in a section along the line II-II of Fig. 1 on a larger scale and Fig. 3 one of the Fig. 2 corresponding representation of a variant of the clamping device.

[0014] The illustrated inflatable weir conventionally comprises a dam in the form of a flexible hose 2, which is attached to a weir base 1 and is watertightly clamped to the weir base 1 by means of clamping rails 3 and to the weir cheeks 5 laterally adjacent to the weir base 1 by means of clamping rails 4. The inflatable weir is controlled by appropriately filling the hose 2 with water in a conventional manner via inlet and outlet lines, which are only schematically indicated by the reference numeral 6.

[0015] According to the invention, a membrane sheet 7 is assigned to the hose weir, which is clamped on the upstream side together with the hose 2 in the clamping rail 3 on the weir base 1, rests on the hose 2, and is anchored on the downstream side at a distance from the hose 2. The arrangement is such that the membrane sheet 7 is freely guided between the attachment to the hose 2 and the downstream anchor 8, forming a flexible guide ramp for the overflow jet.Due to the free sag of the membrane track 7 along a cable curve, advantageous flow conditions for the overflow jet can be easily ensured in order to be able to transmit the overflow jet with largely loss-free laminar flow to the weir bottom 9, which transitions as continuously as possible to the membrane track 7. This allows the energy inherent in the overflow jet to be advantageously used on the downstream side, whether in conjunction with an ejector power plant, to form a standing wave for surfing purposes, or for another use of the kinetic energy of the overflow jet. The largely laminar flow of the overflow jet along the flexible guide ramp also ensures a safe descent of the fish over the weir overflow.

[0016] In order to be able to adapt the course of the membrane sheet 7, for example, to the respective filling of the hose 2 or to other external requirements, the underwater end 10 of the membrane sheet 7 is connected to a tensioning device 11, which can be designed in different ways.

[0017] According to the Fig. 2 the underwater end 10 of the material web 7 forms a loop guide 12 for a weight roller 13 mounted in this loop guide 12, so that a constant tensile stress can be maintained on the freely hanging section of the membrane web 7, which makes additional control interventions unnecessary.

[0018] The Fig. 3 The tensioning device 11 shown comprises a tensioning shaft 14 with a winding drum 15, on which the end 10 of the membrane web 7 is fastened in a tension-resistant manner, so that the sag of the membrane web 7 can be adjusted by means of a corresponding actuating drive for the tensioning shaft 14.

[0019] Since the tensioning device 11 is not intended to impair the laminar flow of the overflow jet, the tensioning device 11 is accommodated in a shaft 16 which is closed at the top by a cover 17 forming part of the weir bottom 9.

Claims

1. Hose weir with a hose (2) which is fastened to a weir base (1) and can be filled with water as a damming body and with a flexible membrane sheet (7) which rests on the hose (2) and is held with its upstream end in a tension-proof manner relative to the hose (2) and is anchored with its downstream end (10) to the weir base (1) at a distance from the hose (2), characterized in that the membrane sheet (7) is freely guided between an upstream abutment on the hose (2) and the downstream anchoring (8) and forms a flexible guide ramp for the overfall stream, and in that the downstream end (10) of the membrane sheet (7) is connected to a tensioning device (11).

2. Hose weir according to claim 1, characterized in that the tensioning device (11) comprises a weight roller (13) mounted in a loop guide (12) of the underwater end (10) of the membrane web (7).

3. Hose weir according to claim 1, characterized in that the tensioning device (11) comprises a tensioning shaft (14) for the underwater end (10) of the membrane web (7).