Manifold

An instrument manifold combines the isolation, equalising and vent valves an instrument needs into one compact block bolted directly to the transmitter or gauge. It replaces a cluster of fittings and valves, reduces leak paths and lets a technician isolate, zero and calibrate a transmitter without breaking the process connection.

The 2-valve manifold (block and bleed) serves gauge and absolute pressure instruments. The 3-valve manifold, with two block valves and an equaliser, is the standard for differential pressure transmitters; the 5-valve adds two vent and test valves for calibration without removing the instrument. Double block and bleed (DBB) manifolds provide two isolation valves in series with a bleed between them for positive isolation on high-pressure and hazardous services.

Connections are threaded, flanged or the IEC 61518 instrument flange pattern, in Class 3000, 6000 and 10000 pressure ratings. Body materials are 316 / 316L stainless steel, duplex, Hastelloy or Monel to match the process; stem packing is PTFE for general duty, graphite for high temperature and fire-safe designs, or PEEK for combined chemical and temperature resistance.

Manifolds are supplied loose, or assembled and pressure-tested with the transmitter, gauge or switch, together with mounting brackets and the correct bolting and gaskets.