Did you know that diaphragm valves were first used in Greece and Rome to control the temperature and flow of water into hot baths? The original diaphragms were made of leather and closed over a weir like design and were manually operated.
The modern diaphragm valve was adapted from this design by a mining engineer, P. K. Saunders, in the early 1900s for controlling air and water supply to underground mines. Patents for the design were filed in 1931 and the Hills McCanna Company became the first licensee to manufacture these valves. Shortly thereafter Grinell, Dow Chemical and Arco-Wynn also entered the market with their own diaphragm valves. The Arco-Wynn design was later licensed by the predecessor of Tru-Tech and thus the diaphragm valve design came to be manufactured in Pittsburgh!