Four-Valve Manifolds

A four-valve manifold double-isolates a differential pressure instrument and puts the vent behind a tamper-proof handle that is removed after operation. That handle is the point of the range: on hazardous fluids, a vent anyone can open is the risk the design exists to remove.

Two configurations are published, both direct mounting. The double isolate / vent block is for services where the process fluid must not be contaminated. The double isolate / equalise / vent block adds an equalising valve on a common drain, for general liquid and gas measurement — it is the one to choose when the transmitter has to be zeroed in service.

Process and drain connections on both are 1/4" NPT (F), 1/4" BSPT (F) or 10 mm OD tube, with a flanged instrument connection. Bodies are A 105 carbon steel, A 182 Gr F 304SS and F 316SS, Monel or Hastelloy. Hydrostatic test is 620 kg/cm² on the body and 413 kg/cm² on the seat, with a 40 kg/cm² pneumatic seat test.