NDL Diaphragm Valve

The NDL (Non Dead Leg T Valve) diaphragm valves, manually or pneumatically operated, are specially designed for use on aseptic processes in the pharmaceutical industry. The valves are widely used at points of use in the loops of purified water (PW) or water for injections (WFI).

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NDL Diaphragm Valve

    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.

    Design and features

    Comparing with a traditional diaphragm valve, the dead leg of an NDL valve is reduced to a minimum due to the design of the valve, and the pharmaceutical normatives like ASME BPE prioritise this condition.

    Broad flexible range based upon a modular design concept with key components being common with other valves.
    Autoclavable stainless steel bonnets and handles.
    Handle with stroke limiter.
    Hygienic design of the handles.
    The valve body is machined out of a stainless steel block.
    Completely drainable design.
    Traceability of components.


    Parts in contact with the product Stainless steel AISI 316L (1.4404)
    Other stainless steel parts Stainless steel AISI 304 (1.4301)
    Plastic parts PP + 30 GF
    Diaphragm EPDM (according to FDA 177.2600 and USP Class VI)

    Surface finish:
    Internal Ra ≤ 0,5 μm
    External Bright polish


    Diaphragm: FPM, VMQ (according to FDA 177.2600 and USP class VI) and PTFE / EPDM separate (according to FDA 177.2600).
    Stainless steel bonnet with plastic or stainless steel handle.
    Pneumatic actuator with stroke limiter.
    Pneumatic actuator with external switch.
    Control box with switches and solenoid valves.
    Materials and roughness certificates.