A N Rubber Industries

The Saunders rubber diaphragm is not simply a thin molded sheet — it is a multi-layer structure composed of rubber (or elastomer) sheets that are calendared (rolled) and vulcanized, reinforced with high-strength fabric (woven textile) to provide durability and flex-life. 

It typically incorporates dual sealing ribs: one rib around the periphery of the diaphragm (where it seats into the valve body) and another rib across the weir (for weir-type valves) to enhance sealing performance and reduce closure torque. 

For rubber (elastomer) diaphragms in general (non-PTFE faced), the diaphragm is a single piece rubber/fabric construction. For PTFE faced diaphragms, the design is two-piece: a PTFE wetted face plus a rubber/fabric backing.

Each diaphragm is batch traceable: moulded with a unique batch number, and physical property data & conformity certificates (FDA/USP etc) are available

The diaphragm completely isolates the process fluid from the valve bonnet/actuator mechanism (i.e., good for corrosive/abrasive/slurry media) which is a hallmark of Saunders diaphragm valve design.