SELECTION OF TYPE OF GATE
1. INTRODUCTION: -
A hydraulic gate is a equipment used for controlling the flow of water through any component of the irrigation system. Generally it holds the water on the upstream side though. Some gates deal with a reversible Water flow in special cases.
2.0 TYPES OF GATE:-
2.1 According to purpose and location of gate:-
2.1.1 Spillway gates: - A gate used to regulate flow over a spillway.
2.1.2 Sluice gate:- A gate which controls or regulates flow. Through an opening where the upstream water level is above the top of the opening.
2.1.3 Draft tube gate:- A gate used to permit dewatering of the draft tubes for inspection and repair of turbine parts and draft tubes and is placed over the draft tube portal under-no-flow condition, although there may be considerable tail, race turbulence at the time.
2.1.4 Barrage gate: - These are a series of gates across the river to regulate water surface level and pattern of flow upstream.
2.1.5 Pick-up-weir gate: - These are the gates provided on the pick-up-weir.
2.1.6 Cross-regulator gate: - A gate in an irrigation channel for the purpose of raising the water level.
2.1.7 Head Regulator gate: - A gate provided at the head of Canal off-taking from a river To regulate the supplies entering the canal and to control silt entry into the canal.
2.1.8 canal escape gate: - The gate provided in the canal escape, to escape surplus or excess water from the canal.
2.1.9 Penstock gate:- The gate provided in the penstock to regulate the flow of water to the turbine in a hydro electric power house.
2.1.10 By pass tunnel gate:- During construction of dam the river water is diverted through a tunnel and the gate located in the tunnel to regulate the flow of river water.
2.2 According to the shape of the Gate:-
2.2.1 Radial Gates:- A hinged gate, the leaf of which is usually a circular are with the centre of curvature at on very near the hinge or turn-on.
2.2.2 Cylindrical gate:- A gate in the form of a hollow cylinder placed in a vertical shaft.
2.2.3 Drum Gate:- A movable crest gate in the form of a sector of a circle hinged at the crest are face effect a water soak with the edge of a recess into which the gate may be lowered. The gate is raised and held up by the pressure of water admitted to the recess form the head water. It is lowered by closing the inlet port to the recess and draining the water form it. The top surface of the drum matches with the curve of the spill-way.
2.2.4 Rectangular gate:- These are rectangular in shape and hence called rectangular gates.
2.3 According to the made of movement of the gate:-
2.3.1 Vertical lift gates:- A gate operating in vertical grooves.
2.3.2 Gates rotating about a fixed exunion point e.g. radial gates, drum gates etc. 2.3.3 Automatic gates:- A gate which functions without external manual attendance.
2.4 According to water head acting on the gate:-
2.4.1 High head gates:- A gate which is subjected to a water head of 30m. Or more above the gate sill.
2.4.2 Medium head gates:- A gate which is subjected to a water head exceeding 15m but less than 30 m. Over sill.
2.4.3 Low head gates:- A gate which is subjected to a water head upto and including 15m above sill.
2.4.4 Differential water head gate: - In this the head of water is at different level acting on both the sides of the gate.
2.5 According to the function of the gate:-
2.5.1 Service Gates:- A gate which operates under unbalanced conditions at part gate opening.,
2.5.2 Emergency gate:- A gate provided on the upstream of a service or a regulating gate to shut of the flow under unbalanced head.
2.5.3 Stop-log gate:- A log, plank, cut timber, steel or concrete beam fitting into end grooves. Between walls or piers to close an opening under balanced condition
Automatically the upstream/down stream water surface at a predetermined constant level,
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