Diaphragm valves restrict or isolate the flow of fluid through a pipe by stretching a flexible plastic or rubber diaphragm across the flow path and pressing it against the other side of the valve body.
These valves were very popular in the past because they provide very tight shutoff while having no “leak path” to atmosphere because the diaphragm was a solid barrier as opposed to ball, butterfly or gate designs.
There are two basic designs of diaphragm valves. In some designs, the flow is directed up over a metal “saddle” that is part of the valve body, allowing for better sealing of the valve, and with less stretching of the diaphragm material. The downside of this design is the torturous path of the fluid and the reduced capacity as a result. The “straight through” design allows for higher flow rates and a “line of sight” glow path, but the diaphragm must stretch further to achieve shutoff, creating more wear and tear on the diaphragm.
Spartan Controls represents two industry leaders for diaphragm valve designs and can assist with you specifying, applying, and procuring products to meet your valve requirements.