DIAPHRAGM VALVES AND DIAPHRAGMS THEREFOR

摘要

A diaphragm (1) for a diaphragm valve includes a peripheral zone (2) which in use is compressed between a flange provided on a valve body and a flange provided on an operating mechanism. The diaphragm (1) includes a relatively flexible inner region (6) and a relatively rigid outer peripheral region (7). The outer peripheral region incorporates a reinforcing element (8) which is substantially completely moulded into the material of the diaphragm so that it is not visible from the exterior of the diaphragm. The reinforcing element (8) may be in the form of a perforated plate (9) of suitable metal. The reinforcing element reduces compression set of the diaphragm periphery to the extent that relatively compressible material such as butyl rubber may be used without the need for periodically re-tightening the diaphragm fixing members.