These are normally used in hydro-elecric high head tunnels where a the use of a wheel or roller gate design is not practical, can be used to control the flow through the tunnel.
- Can be used for very high heads up to 200m
- Side groove sizes can be kept to a minimum to reduce flow disturbance.
- Sealing faces are metal to metal slides.
- Can be rectangular or circular bore.
- Normally configured as Service + Guard gates for maintenance
- High lifting loads due to excessive friction.
- Needs large downstream air vent.