Operating principle

The diaphragm provides the body seal as well as the seat seal. There are no paths to the outside environment and, as such, the valve is suitable for aseptic processes. When the valve is being closed, a pressure pad which supports the diaphragm moves towards the sealing face on the body. As the pressure plate moves, the diaphragm flexes and is forced down onto the seat area in the centre of the body, thus, closing off the flow path through the body.

The valve can be actuated either manually or pneumatically and controlled by control units and solenoid valves.

A standard diaphragm valve is used to shut the flow of a line, an NDL type valve shuts only one outlet of the main line.