RU2090695C1 - Power intake for offtake of water from surface layers of water storage reservoirs - Google Patents

Abstract

FIELD: hydraulic engineering, in particular, designs of power intakes at high- and mean reservoir-head dams. SUBSTANCE: intake of concrete dam includes water races with diversion chamber located before inlets on cantilevers. Chamber body is formed on the side of water reservoir by water overflow device whose lower part made in form of blank wall and middle part, in form of removable shields, and upper part, in form of trash screens. Made in bottom of diversion chamber are water intake holes each of which is provided with trash screen and gate in form of flap installed for opening it inside diversion chamber. Each flap is connected by means of flexible link with its control mechanism. weight of flap in closed position is determined by condition Mg-Mp, where Mg is value of moment from flap weight relative to its axis of rotation; Mp is value of moment from water load exerted onto flap with rated level drop in water reservoir and diversion chamber. EFFECT: higher efficiency. 2 cl, 2 dwg

Description

 The invention relates to hydraulic engineering and can be used in high- and medium-pressure dams for water intake from the surface layers of the reservoir.

A well-known water intake of a hydroelectric power station for water intake from the surface layers of the reservoir, including an advance chamber located in front of the inlet of the pressure conduit, the casing of which is waterproof at the bottom and equipped with a water overflow device, and a trash guard installed at the inlet to the pressure conduit [1]
The disadvantage of such a water intake is the high pressure loss at the inlet to the water conduit due to the high pressure loss on the trash holding lattice located in the zone of high speeds.

A water intake is known, including an upstream chamber located in front of the inlet of the pressure conduit, the casing of which is waterproof at the bottom and is equipped with a water overflow device made with a through upper part in the form of trash racks, while the water overflow device is installed with the possibility of vertical movement when the level changes reservoir water [2]
The disadvantages of this water intake are its low reliability and complexity of operation due to the possible, especially in the first years of the HPP operation, unexpected and unpredictable clogging of gratings. As a result, significant pressure losses can occur (the difference in water levels in the reservoir and in the fore chamber), which are preserved in the spring and autumn periods of the year, when water withdrawal only from the surface layer is not required. Additionally, under the influence of the difference in water levels, high loads arise on the grilles and all other elements of the fore chamber chamber.

 The technical result from the use of the invention is to increase the reliability of the water intake and simplify its operation due to the automatic limitation of the difference in water levels in the reservoir and in the fore chamber and due to the possibility of reducing this difference in periods of the year in which water intake from the deep layers is allowed.

This technical result is achieved due to the fact that in the water intake of the hydroelectric power station for water intake from the surface layers of the reservoir, including an avancamera located in front of the inlet of the pressure water conduit, the casing of which is made waterproof in the lower part and equipped with a water overflow device made with a through upper part in the form of trash racks, while the water overflow device is installed with the possibility of vertical movement when the water level in the reservoir changes nilische according to the invention in the bottom forebays comprises at least one water inlet opening, and equipped with a trash screen in the form of leaf shutter, installed with the possibility of opening inwardly forebays, the sash weights in a closed position determined by the condition
M _g M _p ,
where M _{g the} magnitude of the moment of the weight of the sash relative to its axis of rotation;
M _{p the} magnitude of the moment from the load of water on the sash at the calculated difference in water levels in the reservoir and in the fore chamber.

 Additionally, the sash is equipped with a control mechanism.

 The essence of this technical solution lies in the fact that in the event of a difference in the water levels exceeding the calculated one, under the influence of this level difference, a sash is opened in the bottom of the fore chamber, as a result of which additional water enters the fore chamber from the deep layers of the reservoir, which prevents further increase in the water drop on the grates. After cleaning the grates, the sash closes under the action of its weight in a natural way. In periods of the year when water is allowed to be taken from the deep layers, an additional mechanism is used to open the sash to its extreme position.

 In FIG. 1 shows a water inlet with an advance chamber located on the consoles, a cross section; in FIG. 2 water inlet with a floating advance chamber, cross section.

The intake of the concrete dam 1 includes pressure conduits 2, each of which is equipped with emergency shutters 3 and repair 4, and in front of the inlet openings 5 of the conduits 2 on the consoles 6 there is a common for the entire station (aggregate) part of the dam and equal in length to the chambers 7, whose body formed from the ends by the extreme bulls 8, extended towards the upstream, from the bottom 9, from the side of the dam 1 by beams 10, and from the side of the reservoir by a water overflow device, the lower part of which is made in the form of a blank wall 11, the middle Ya in the form of removable shields 12, and the upper part - through in the form of trash racks 13. Removable shields 12 and trash racks 13 are installed in the grooves of the intermediate bulls 14, located on the consoles 6 and rigidly interconnected by longitudinal crossbars 15, and with a dam 1 transverse crossbars 16. Along the length of the chambers 7, water receiving holes 17 are made in its bottom 9, each of which is equipped with a trash holding grid 18 and a shutter in the form of a sash 19, which is installed with the possibility of opening it inside the chambers. Each leaf 19 by a flexible rod 20 is connected to the mechanism 21, while the weight of the leaf in the closed position is determined by the condition
M _g M _p ,
where M _{g the} magnitude of the moment of the weight of the sash relative to its axis of rotation;
M _{p the} magnitude of the moment from the load of water on the sash at the calculated difference in water levels in the reservoir and in the fore chamber.

 The operation of the water intake is as follows.

 With fluctuations in the water level in the reservoir, the height of the overflow device is changed by maneuvering with removable shields 12 and trash racks 13 using a crane 22 so that only water is taken from the surface layers of the reservoir (warm in summer and cold in winter) to the extent necessary for normal operation hydroelectric power stations. If the difference in water levels on the gratings of the calculated value is exceeded under the influence of such a difference, the sashes 19 are slightly opened by turning around their hinges 23 to an intermediate position, as a result of which additional water enters the chamber through openings 17 from the deep layers of the reservoir. Due to this, a further increase in the level difference is prevented, and after cleaning the trash grids 13, the shutters 19 are closed under the influence of their weight g. In the periods of the year when water can be taken from the deep layers (in spring and autumn), the shutter 19 is completely opened by the mechanism 21, as a result of which the water intake area of the chambers is increased, and, consequently, the pressure loss of the water on the trash racks is reduced.

 If necessary, the cleaning of the grilles 18 can be carried out by jets of water that are formed at the outer surface of the grilles with nozzles (not shown) located around the perimeter of the water inlet 17, while the grill can be made convex to the pressure side.

 Similarly, water intake openings 17 are made and are equipped with trash grids 18 and flaps 19 in the case of an avanchamber in the form of a box 24 (Fig. 2), the adjustable buoyancy of which is ensured by the hollow elements of its frame 25, and containing a water overflow device with trash grids 26 in its perimeter the upper part and is held in plan before the inlet 5 of the water conduits 2 with a load 27 located above the safety trap 28, and a cable-block mechanism 29 connected to the duct 24.

Claims (2)

1. The intake of the hydroelectric power station for water intake from the surface layers of the reservoir, including an advance chamber located in front of the inlet of the pressure conduit, the casing of which is made waterproof in the lower part and equipped with a water overflow device made with a through upper part in the form of trash grids, while the water overflow the device is installed with the possibility of vertical movement when changing the water level in the reservoir, characterized in that in the bottom of the fore chamber made at least one water inlet equipped with a trash guard and a shutter in the form of a sash installed with the possibility of opening it inside the chamber, while the weight of the sash in the closed position is determined by the condition
M _d M _p
where M _{d the} magnitude of the moment of the weight of the sash relative to its axis of rotation,
M _{p is the} magnitude of the moment from the load of water on the sash at the calculated difference in water levels in the reservoir and in the fore chamber.  2. The water intake according to claim 1, characterized in that the sash is equipped with a control mechanism.

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