The flap and radial gate shutters are used for water level control. The level is controlled from the threshold to the height of the weir segment body. Thanks to their service properties, the weir flap shutters are the most widely used gate device for the head up ro 5 m. Radial gates are used for the head up to 12 m.
The flap and radial gate weir shutters are used as gate structures of weir pools, safety diversion weirs of dams and lock chamber gates. To large extent,the flaps are used as gate or segment superstructures, where they are used for finer control of the spillway jet.
From the various flap types, those with a pipe and particularly hollow flaps are used most frequently today for their higher spatial rigidity. Hydraulic motors are primaly used as motion mechanism: the flap is either suspended on them or supported by them. For ecological and operational reasons, flaps controlled from a pillar are selected preferably, particularly with pipe and hollow flaps with an adjusted pipe extended to the pillar. Pipe flaps are suitable for use up to the damming height of about 2 metres at the weir sluice clear span of up to 15 metres and one-side control.
Hollow flaps have a much higher carrying: therefore,they can be designed for damming height of 2–5 metres at the weir sluice clear span of 15–20 metres, although they have already been constucted for the damming height of up to 6 metres and the sluice clear span of 40 metres.
The structural part of the weir is favourably stressed with the flaps because the load from the flaps is totally or largely transferred along the entire length of the substructure so that the pillars can be low and relatively narrow. Another advantage of these flaps is the possibility of fine control of the water level in the spillway. This also brings the advantage of smooth passage of ice floats and other floating subjects through the partly closed flap body.
Design of weir and radial gate flap shutters:
- material grade 11
- or stainless grade 17
- surface finish
Weir shutter control: one-side or double-side from pillars, by means of a hydraulic motor or pin bar and mechanism.
Radial gate control: double-side, mechanic or hydraulic
- mechanic- electric motor, transsions, Galls chain with chute or cable
- hydraulic-pumping unit, hydraulic motor swivelling on a structure bracket, piston rod connected to the segment arm
- ČSN 73 1404 – Design of Steel Structures of Water Management Structures
- ČSN 73 2601 – Construction of Steel Structures
- ČSN 73 2611 – Dimension and Shape Deviation of Steel Structures
- ČSN EN ISO 13 920 – Welding-General Tolerances for Welded Constructions – Dimensions for Lengths and Angles-Shape and Position
- Hollow flap
- Pipe flap
- Free roller flap
- Radial gate