Valve is a device that regulates, directs or controls the flow of a liquid (gas, liquid, fluidized solid) by opening, closing, or closing part of the flow path.
Valve (valve) in everyday life, the most obvious is in water pipes, such as taps for water. Other familiar examples include gas control valves on the stove, small valves installed in the bathroom and many more.
Valves play an important role in industrial applications ranging from drinking water transportation to controlling ignition in rocket engines.
The valve can be operated manually, both by the handle, pedal lever and others. Besides being able to be operated manually the valve can also be operated automatically by using the principle of changes in pressure flow, temperature etc. These changes can affect the diaphragm, spring or piston which in turn activates the valve automatically.