The Sunken type of flow plate is ideal for situations where you wish to control traffic in one direction only.
The main box is sunken into the road surface leaving the counterbalance flap protruding. Once a vehicle has driven over the flap in the correct direction, the flap returns to an upright position. Preventing unauthorised entry from the opposite direction.
It is advised to place speed bumps before these flow plates so vehicle speed is reduced, as the plate should be driven over at no more than 5mph.
The Sunken flow plate is concreted into the ground flush with the surface, connecting drainage ducts to the main drains.