All About Diaphragm Valves
Basic engineering devices such as valves contribute to almost every complex system. These mechanical/electromechanical devices regulate media flow and come in dozens of unique varieties; to see all the different types of valves, visit our understanding valves article. The diaphragm valve will be the focus of this article, and we will explore what they are, how they work, and the different types available. Through this investigation, this article should help decide if diaphragm valves could be useful, and how to choose the correct version for a given application.
What are diaphragm valves?
Diaphragm valves are bi-directional, on-off throttle valves. They are used to control fluid flow by regulating the area with which media can enter and exit the valve, effectively changing its speed and velocity. They are so-called “diaphragm” valves because a thin, flexible membrane is used to control the opening and closing of the valve. They can be made with metal such as stainless steel, plastic, and even single-use materials. Diaphragm valves are like pinch valves but they use a linear compressor which pushes the thin diaphragm into contact with the valve body. They offer discrete and variable pressure control and can be both manually and automatically actuated. Diaphragm valves are clean, leak-proof, easy to maintain, safe, and effective valves that are best suited for moderate pressure & temperature applications which require stop/start fluid control.
How do diaphragm valves work?
Diaphragm valves are simple in construction and operation. As shown in Figure 2, a valve actuator is in contact with the inner membrane (or “diaphragm”) of the valve in its open position. When the user desires the valve to be shut, the actuator is pressed and/or turned and the membrane is pushed into the edge of the solid damn, closing the valve. Certain diaphragm valves can also have half open/restricted positions where the membrane is partially closed, allowing a throttled flow through the valve. In the next section, we will examine the broad categories of diaphragm valves and where they are most useful.