Wafer Check Valves
Wafer check valves are short-bodied non-return valves designed to be clamped directly between two pipe flanges, with the flange bolts spanning the pipeline rather than threading into the valve body. "Wafer" describes the body pattern and end style rather than the internal mechanism: a wafer check can carry a single swinging disc, a tilting disc, or a pair of spring-loaded dual plates. The defining benefit is compactness — the very short face-to-face length and low weight save space and pipe-support load compared with a flanged swing valve.
Wafer-pattern check valves are covered by API 594 (Type "A"), which fixes face-to-face dimensions, ratings and test requirements for wafer, lugged-wafer and double-flanged bodies; pipeline-class wafer checks may also carry API 6D. Sizes commonly run from 2" to 48" across ASME 150 to 2500 (PN 16-420). The lugged-wafer variant adds tapped lugs so the valve can be used at the end of a line or removed without disturbing the upstream pipe, and supports dead-end service.
Materials span WCB / A216 carbon, CF8 / CF8M (A351 SS304/316), duplex and super-duplex, plus bronze and aluminium-bronze for seawater duty and Inconel or Monel for aggressive media. Seats are soft (RPTFE, Viton, NBR) for bubble-tight closure or metal with stellite for high temperature. Centring is achieved on the flange bores, and the valve relies on the mating flange gaskets for its end seal.
Wafer checks are self-actuating; where the internal element is a dual plate, the spring rate sets the cracking and closure characteristic, giving non-slam behaviour. Fire-safe API 607 / 6FA construction can be specified where the line forms part of a hydrocarbon or ESD system.
Himalay's MSME partners manufacture wafer check valves with testing per API 598 / BS EN 12266-1 / ISO 5208, material traceability, and PED-CE (EU), SABER (Saudi Arabia), and NACE MR0175 (sour service) coordinated as part of the standard order flow.
