Gates and Valves for Flow Control

Views:
 
Category: Entertainment
     
 

Presentation Description

No description available.

Comments

Presentation Transcript

Diapositiva 36:

Gates and Valves for Flow Control Lesson 10

Diapositiva 36:

Instructional objectives On completion of this lesson, the student shall learn:   1. The different types of gates and valves used in water resources engineering 2. Difference between crest gates and deep seated gates 3. Classification of gates 4. Design criteria for important gates 5. Common hoists for gate lifting 6. Different types of valves for flow control Gates and Valves for Flow Control

Diapositiva 36:

Some of the important terminologies associated with gates are given below Counter weight A weight used for opposing the dead weight of a gate so as to reduce the hoisting capacity. Frame A structural member embedded in the surrounding supporting structure of a gate Hanger A device meant for suspending or supporting a gate in the open position when disconnected from its hoisting mechanism. Gate groove or gate slot A groove or slot is a recess provided in the surrounding structure in which the gate moves rests or seats.

Diapositiva 36:

Leaf The main body of a gate consisting of skin plate, stiffeners, horizontal girders and end girders. Lip The lower most segment of a gate which is suitably shaped from hydraulic consideration. Seal (Bottom, side and top) A seal is a device for preventing the leakage of water around the periphery of a gate. Sill This is the top of an embedded structural member on which a gate rests when in closed position. Guide That portion of a gate frame which restricts the movement of a gate in the direction normal to the water thrust.

Diapositiva 36:

Guide rollers Rollers provided on the sides of a gate to restrict its lateral and/or transverse movements. Guide shoe A device mounted on a gate to restrict its movement in a direction normal to the water thrust. Horizontal and vertical girders Horizontal girders are the main structural members of a gate, Vertical girders are the structural members to support the skin plate. Hydraulic down-pull The net force acting on a gate in vertically downward direction under hydrodynamic condition.

Diapositiva 36:

Hydraulic uplift The net force acting on a gate in vertically upward direction under hydrodynamic condition Lift of a gate The maximum vertical travel of a gate above the gate sill. Lifting beam A beam (with a gripping mechanism) suspended from a gantry crane and moves vertically in a gate groove for lifting Lifting lugs Structural members provided on a gate to facilitate handling of the gate during erection, installation or operation.

Diapositiva 36:

Air vent A passage of suitable size provided on the downstream of the gate for venting / admitting air during filling / draining a conduit or for delivering a continuous supply of air to the flow of water from a gate. Anchorage An embedded structural member, transferring load from gate to its surrounding structure. Bearing plate A metal plate fixed to the surrounding surface of the frame to transfer water pressure to gate frame. Gate Frame or Embedded Part of Embedment A structural member embedded in the surrounding supporting structure of a gate, which is required to enable the gate to perform the desired function

Diapositiva 36:

Thrust Pad or Thrust Block A structural member provided on a gate leaf to transfer water load from the gate to a bearing plate. Skin plate A membrane which transfers the water load on a gate to the other components. Track Plate A structural member on which the wheels of a gate move. Trunnion axis The axis about which a radial gate rotates. 26. Trunnion Pin A horizontal axle about which the trunnion hub rotates.

Diapositiva 36:

Trunnion Tie A structural tension member connecting two trunnion assemblies of a radial gate to cater to the effect of lateral force Block out A temporary recess/opening left in the surrounding structure of a gate for installing the embedded parts of a gate. Liner Steel lining generally provided in the gate groove and its vicinity for a medium or high head installation. Filling Valve A valve fixed over a gate to create balanced water head conditions for gate operation

Diapositiva 36:

4.10.1 Classification of gates based on location of opening with respect to water head Crest type gates   Stop-logs /flash boards Vertical lift gates Radial gates Ring gates Stoney gate Sector gates Inflatable gates Falling shutters Float operated gates Two-tier gates Deep seated gates Vertical gate Deep-seated radial gates Disc gates Cylindrical gates Ring follower gates Jet flow gates Ring seal gates

Diapositiva 36:

1. Stop-logs /flash boards A log, plank cut timber, steel or concrete beam fitting into end grooves between walls or piers to close an opening under unbalanced conditions, usually handled or placed one at a time

Diapositiva 36:

2. Vertical lift gates These are gates that moves within a vertical groove incised between two piers. The vertical lift gates used for controlling flow over the crest of a hydraulic structure are usually equipped with wheels

Diapositiva 36:

3. Radial gates These are hinged gates, with the leaf (or skin) in the form of a circular arc with the centre of curvature at the hinge or trunnion

Diapositiva 36:

4. Ring gates A cylindrical drum which moves vertically in an annular hydraulic chamber so as to control the peripheral flow of water from reservoir through a vertical shaft

Diapositiva 36:

5. Stoney gate A gate which bears on roller trains which are not attached to the gate but in turn move on fixed tracks.

Diapositiva 36:

6. Sector gates A pair of circular arc gates which are hinged on vertical axis in a lock. These gates are used in navigation locks where ships pass from a reservoir with a higher elevation to one with a lower elevation.

Diapositiva 36:

7. Inflatable gates These are gates which has expandable cavities. When inflated either with air or water it expands and forms an obstruction to flow thus effecting control

Diapositiva 36:

8. Falling shutters Low head gates installed on the crest of dams, barrages or weirs which fall at a predetermined water level.

Diapositiva 36:

9. Float operated gates A gate in which the operating mechanism is actuated by a float that is pre-set to a predetermined water level. These may be used as escape in canals or even in dams to release water

Diapositiva 36:

10. Two-tier gates A gate used in two leaves or tiers which can be operated separately, but when fully closed act as one gate. These types of gates are used to reduce the hoist capacity or the lift of the gate

Diapositiva 36:

1. Vertical gate Similar to that used for crest type gates , but usually for deep-seated purposes like controlling flow to hydropower intake either the ones with roller wheels

Diapositiva 36:

2. Deep-seated radial gates These are low level radial outlet gates. These gates have sealing on top apart from on all sides. They are located at sluices in the bottom portion of dam

Diapositiva 36:

3. Disc gates A gate, which is in the form of disc, and rotates about an axis of its plane to control the flow of water.

Diapositiva 36:

4. Cylindrical gates A gate in the form of a hollow cylinder placed in a vertical shaft. These gates are used usually for intake towers, upstream of dams for shutting off the water to penstocks and control values .

Diapositiva 36:

5. Ring follower gates These are gates with a slide gate with a circular ring (a leaf with a circular hole) extending below the gate leaf. It is used as emergency gate upstream of a regulating or service gate and is operated either in fully closed or fully open position

Diapositiva 36:

6. Jet flow gates A high pressure regulating gate in which the leaf and the housing are so shaped as to make the water issue from the orifice in the form of a jet which skips over the gate slot without touching the downstream edge of the slot

Diapositiva 36:

7. Ring seal gates A roller or wheel mounted gate in which the upper portion of the gate leaf forms a bulkhead section to stop the flow of water and the lower portion forms a circular opening. This type of gate is usually used as either service or emergency gates in the penstocks or other conduits.

Diapositiva 36:

4.10.2 Classification of gates based on the type of flow passage with which connected and its location Crest gates Sluice gates Depletion sluice gates Construction sluice gates Diversion tunnel gates Head regulator and Cross regulator gates Desilting chamber gates / Silt flushing gates Head race tunnel gates Surge shaft gates Penstock gates / Intake gates Draft tube / Tail race gates Navigation lock gates Balancing gates

Diapositiva 36:

1. Crest gates A gate mounted on a crest for the purpose of controlling the discharge flowing over the crest of the spillway of a dam or a barrage

Diapositiva 36:

2. Sluice gates These are gates which controls or regulates flow through an opening or sluice in the body of the dam where the upstream water level is above the top of opening

Diapositiva 36:

A gate located at lowest level in the body of the dam to deplete the reservoir in the event of distress. It may be either wheel mounted type or sliding type. 4. CONSTRUCTION SLUICE GATES This gate is meant for closing a construction sluice which is normally plugged after construction. 3 . DEPLETION SLUICE GATES

Diapositiva 36:

5 . Diversion tunnel gates This gate is meant for making diversion tunnel dry, when it has to be plugged after construction

Diapositiva 36:

6. Head regulator and Cross regulator gates The Head regulator gates are used for regulating water from reservoir to main canal. The Cross regulator gates are used in an irrigation channel for the purpose of raising the water level. 7. Desilting chamber gates / Silt flushing gates These gates are located at the exit of desilting chamber of a hydroelectric plant to flush out accumulated silt. 8. Head race tunnel gates A gate installed at the entrance of head race tunnel of hydroelectric project. It is generally a wheel mounted gate

Diapositiva 36:

9. Surge shaft gates Surge shaft gate is used for inspection of tunnel / penstock and is located in the vicinity of surge shaft and tunnel junctions. 10. Penstock gates / Intake gates A gate provided at the upstream end of the penstock. 11. Draft tube / Tail race gates A bulkhead gate used to permit dewatering of the draft tubes for inspection and repair of turbine parts and draft tubes.

Diapositiva 36:

12. Navigation lock gates These are gates provided on navigation locks. Is a lock gate comprising of two hinged symmetrical leaves which meet at the centre of the lock channel when in the closed position and fit into recesses in the side walls of the channel when open

authorStream Live Help