8.2　Sluice Gate and Hoisting Device

8.2　Sluice Gate and Hoisting Device

8.2.1　Bulkhead gates should be installed on the upstream side of spillways and service gates of weir sluices；emergency gates may also be installed for important projects.If the duration of reservoir water level being lower than the gate sill is sufficient for overhaul，it is not required to build bulkhead gates；if the sill is always submerged under the downstream water level，the necessity of installing downstream bulkhead gates shall be studied.

One or two bulkhead gates may be set for the hydropower station with service gates less than 10，and the number of bulkhead gates should be increased if there are more than 10 services gates.The types of bulkhead gates may be selected among flat gate，stop log，floating stop log and floating caisson gate，etc.

8.2.2　Emergency gates shall be installed upstream of the service gate of discharge orifice.For long discharge orifice with high water head，the necessity of installing bulkhead gates in front of the emergency gates shall also be studied.

8.2.3　Free flow should be maintained behind the service gate of discharge orifice.

8.2.4　Radial，flat or other types of gates（valves）may be selected as service gates of discharge orifice.Radial gates should be used if the operating water head of gate（valve）is higher than 50m，while fixed cone valves or flow regulating valves may also be used.

If a radial gate is used，the best water seal structure and type shall be selected；if a flat gate is used，an appropriate type of gate slot shall also be selected.The pivot bearing of the radial gate should be installed at the elevation that is not impacted by water flow or floating debris during the passage of water.

If the fixed cone valve or flow regulating valve is adopted at the outlet of water release structure，measures to prevent the impact of water spray on adjacent structures shall be taken.(https://www.daowen.com)

8.2.5　Silt orifice gates should be installed at the intake，while panels and water seal should be installed on the upstream side.The boundary of gate slot and water way should be smooth and flat and protected by using anti-wear materials.

Ifa silt orifice service gate is installed at the outlet，the orifice channel shall be protected by using antiwear materials；moreover，the emergency gate at the intake should be closed to retain sediment during normal operation.

8.2.6　The construction diversion orifice gate and its gate slot shall meet the requirements of various operating conditions during the construction period and the initial power generation period.After analysis and verification，the diversion orifice gate may also be used as a permanent gate.

The capacity of hoists used to control the diversion orifice gates shall be designed with consideration of the requirement for opening and closing gates in flowing water under a certain water head，and the hoists shall be equipped with opening indicating devices.

8.2.7　For low water head radial gates，the dynamic stability of gate arms shall be ensured.

8.2.8　If all of the multi-opening flood discharge service gates need to be opened in a short time or to release water evenly，the operation should be accomplished by using a fixed hoist.

8.2.9　A reliable standby power source shall be available for the hoists used to control flood discharge and other emergency gates.