Follett PB501733

WASHER VALVE STEM

Valves are widely used in different restaurant equipment designs. A valve is a device that regulates, directs or controls the flow of a fluid (gases, steam, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. In an open valve, fluid flows in a direction from higher pressure to lower pressure. 

Valves may be operated manually, either by a handle, lever, pedal or wheel. Valves may also be automatic, driven by changes in pressure, temperature, or flow, allowing control over a variety of operational requirements. 

A washer is a thin plate (typically disk-shaped, but sometimes square) with a hole (typically in the middle) that is normally used to distribute the load of a threaded fastener, such as a bolt or nut. Other uses are as a spacer, spring (Belleville washer, wave washer), wear pad, preload indicating device, locking device, and to reduce vibration (rubber washer). Spring washers, which have axial flexibility are used to prevent fastening or loosening due to vibrations. Locking (lock) washers prevent fastening or loosening by preventing unscrewing rotation of the fastening device.