Specifically designed for arduous, off seating duty with zero leakage
Wedge gates are a type of penstock utilising a whole of gate wedging action. Knife wedge gates are a variation specifically for grit prone invert situations. They can be used for circular or rectangular openings, are drip tight, and designed specifically for the application and duty.
The seal on the frame is neoprene. The sliding surface for the gate is UHMW Polyethylene, a low friction proven material in aggressive water environments.
The higher the closing load applied by the stem, the higher the sealing pressure on the neoprene seal. This is unlike a knife gate valve that closes vertically by necessity of the outside flange.
The concept is not unique. A number of manufacturers use it, especially in North America. Wedge action has been applied to cast iron penstocks for over a century. What is unique is the combination of new technologies; the knife action into sand filled inverts, the cantilevered lower gate, full length wedges rather than individual ones which have to be staggered horizontally and the application of new technologies that have emerged in the past couple of years.