water gates

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classification of gates
a)High head gates,which operates under high head of 30m and above
b)Meadium head gates,which operates head of 15m ad above and below 30m

c)Low head gates ,which operates under head of less than 15m
Design of gate involve design of skin plates,stiffners,wheel and wheel tracks seals and accesories etc
The gates shall be reasonably water tight ,it shall capable of beingraised or lowered etc.
the gates shall be designed for the hydrostatic and hydrodynamic forces,water loads etc taking in to consideration.
Hydro Gate’s standard radial gate is designed for a wide, clear  waterway opening. A radial (or taintor) gate acts similar to a section of a drum. Pressure is transferred from the curved face   through the horizontal support beams to the radial arms at the sides of the opening. The arms act as columns and transfer thrust to a    common bearing located on either side of the gate opening. Flow is underneath the curved face as the gate is
opened. This design results in a lightweight, economical gatethat can be opened and closed with minimum effort and with comparatively small number of turns of the handwheel on thehoist.Hydro Gate radial gates are made for two types of installations.The first, and most commonly used, is an overflow type. Thisgate is designed for 1 ft of water flowing over the top of the gate when the gate is closed. Adequate safety factors prevent damage to the gate if there is a moderate, additional overflowbeyond that limit for a short period of time.The second type employs the use of a breastwall. This is avertical concrete wall above the top of the gate opening that results in additional storage capacity in front of the gate. Mostradial gates are raise-to-open type, a variation is the lower-toopen type. This requires a weir wall for mounting a seal that must make contact with the curved face plate. Silt and debris entrapment is a problem with this arrangement.
Gate Face
The standard radial gate face is constructed by using horizontal structural members and a curved face plate.The curved steelface plate is 1/4 in. minimum thickness.The face plate is attached to the horizontal structural membersby welding. Sufficient holes are located around the perimeterof the assembly for attaching the seals.Horizontal Support BeamsHorizontal face support beams are made from structural steelchannels. These beams vary in size with the width of the gateand maximum head of water. They also vary in quantity andspacing with the height of the gate. Welded to the end of eachchannel is a heavy steel gusset with holes punched to receivethe side arms. These support beams are normally painted.They can be hot-dip galvanized for additional corrosionprotection.SealsSide SealsSide seals on both the overflow and breastwall gates are made from neoprene.The standard side seal is a J-seal bolted to the edge of the face plate and is held in
place by a steel retainer bar. The side seal is adjusted to compress against the siderubbing plate to form a watertight seal.
Bottom Seal
The bottom seal is also a J-seal that isattached to the gate by bolting. As the gate closes, its weight causes a slight deflection in the seal as it contacts the invert of the opening. This flexibility allows the bottom seal to compensate for slight irregularities in the concrete floor. However, if the floor is out of level by
more than 1/8 in., the seal will not compensate for this much difference and excessive leakage will result. To minimize this possible discrepancy in construction, an adjustable sill asdescribed in this section is recommended.
Top Seal
The top seal on a breastwall-type radial gate is made by attaching a flat section of rubber to the underneath side of the breastwall. An angle attached along the top front face of the gate projects toward the breastwall and forms the other portion of the seal. As the gate is closed, the protruding leg on the
angle makes contact with the rubber projecting from the breastwall and seals the space along the top of the opening.The hoist ropes pass through a slit in the seal, allowing some
leakage.Radial Arms and Pin Plate Radial arms are fabricated from structural steel angles, with larger and thicker angles being used as the gate height increases. Each angle acts as a column in transmitting the load
from the face support channel to the pin plate. The forward or  upstream end of each angle is punched with holes to match those in the gusset plate. The back end of each angleterminates at a common pin plate in a fan-like arrangement.This steel pin plate is made thicker as the gate height, width,and head increase. A steel collar is welded to the pin plate to form a hub to receive the pin. The hub and pin are cross drilled to hold the gate pin in position. The pin is removable tofacilitate installation of the gate. The entire assembly is
painted, or it can be hot-dip galvanized along with the face support beams.The hoist consists of a worm gear arrangement with doubledrums for winding two cables simultaneously. The individual
cables run from each drum to the bottom corners of the gate
face.
The hoist gear box consists of a worm and worm gear totallyenclosed in a cast iron housing. The housing attaches to a bracket, which in turn anchors to the top of the wall or asupport beam. The drum shaft is a fabrication consisting of the drum tube spanning the opening and flanges for the rope and
stub shafts at each end. One end is supported on a pillow block, the other by the gear box and bulkhead bearing. The worm is attached to a vertical shaft extending out of the gear box and is supplied with a handwheel. A typical hoist installation is shown below.
Motor Operation
Hydro Gate hoists can be motorized using an electric valve actuator attached to the top of the hoist to drive its vertical input shaft. The unit also includes an electric motor; reversing controller; push-button stations for raise, stop and lower; two indicating lights; geared limit switches; torque switches; and handwheel for emergency operation.
Automatic Operation                                                                                                                                   A hoist with an electrically operated lift mechanism can be equipped for automatic operation of the radial gate by use oflogic controls to control flow and level, or to interface with other process controls.
Adjustable Sill and Side Rubbing Plates
To improve the operation and water-tightness of a radial gate,adjustable side rubbing plates and an adjustable bottom sill are recommended. These plates are available in stainless steel or galvanized steel.
During construction, a recess is left at the sides and bottom of the gate opening where the adjustable rubbing plates and the bottom sill are to be mounted. Anchor bolts are set in the forms and extend into the recesses. Projection of these anchors is less than the depth of the recess.When forms are stripped, the adjustable plates are installed on the projecting anchors. By use of double nuts on each anchor, the side rubbing plates and bottom sill can be properly aligned. Side rubbing plates are adjusted with the gate closed to obtain a good seal fit and compression. Side seals and side rubbingplates should be adjusted so that a slight wedge-shaped
opening is formed to reduce seal drag and wear as the gate opens. The bottom sill plate must be flat across its entire width, in good contact with the bottom gate seal, and as flush
as possible with the invert. As an alignment check, the gate should operate to ensure that proper contact is being made with the rubber seals on the gate. All plates are then grouted in to complete the gate installation.
The drawings on page 5 show details of adjustable side rubbingplates and of the adjustable bottom sill.
Side Seals
Another type of side seal available is the flat type. This is a more economical seal due to the fact that side rubbing plates are not required. It can be used for retrofitting gates in existingstructures where cutting and chipping of concrete for placement of rubbing plates is not desired. The walls must be parallel, flat
and perpendicular to the invert within the compliance of the flatseal. Leakage control provided by flat-type seals may not be as good as leakage control provided by J-seals and rubbing plates.
 
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