What is Pressure Gauge?
A pressure gauge is a device for pressure measurement of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. A pressure gauge has a needle indicator to show the user instantaneous pressure. Piston type and diaphragm type are two of the more commonly used types.
Piston type pressure gauge consist of a piston that separates the low pressure and high pressure region. There are two ports for low pressure and high pressure. A difference in pressure creates movement in the piston. The movement of the piston is transferred to the pointer via magnetism. Magnetic ring of the pointer follows the magnetic piston as it moves along the bore. The piston is supported by the measuring range spring so that the movement of piston is proportional to the pressure acting on it.
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A diaphragm type pressure gauge consist of a diaphragm or membrane, which can be either made of metal or other material that acts as the sensing element for the gauge. The diaphragm deforms when pressure is applying force on it. It is connected to a mechanism which amplifies the movement of the diaphragm and transfer that to the pointer to show the pressure reading.