- This grate is show in Fig. 14.24.
- It consists of a steel cylinder as large in diameter as the height of the opening and spanning between the piers.
- Each pier has an inclined rack.
- The gate is wound around the periphery of the cylinder.
- The gate is also attach to the incline rack with the help of toothed gears.
- ItGate can be roll while opening and unroll which closing the gate.