A diaphragm valve is a control device that utilizes a flexible membrane to close, or shut, an opening. Pressure increase or decrease on either side of the diaphragm causes the valve to move its position. Often, these valves are used in industries like food processing, pharmaceutical manufacturing, mining, and pollution control, among others. They can be made from a variety of plastics and metals, depending on which application they will be used for.The operating power for a diaphragm valve can come from a variety of sources. A pneumatic diaphragm valve uses air pressure to open or close it. Sometime a solenoid, a wire-wrapped metallic component that can produce a magnetic field in the presence of electricity is employed to actuate the valve. Other times, it can be operated manually. In addition, hydraulic pressure is also commonly utilized.