Pressure Measurement

Pressure Gauge

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.


Working Principles

Piston Type

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.  

piston type pressure gauge working principle diagram

Image Courtesy: Wika

Diaphragm Type

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. 


midwest 120 series piston type pressure measurement

120 Series

Differential Pressure
Piston Type
Compact Design
Up to 6000 PSIG

midwest 130 series diaphragm type pressure measurement

130 Series

Differential Pressure
Diaphragm Type
Up to 500 PSIG

midwest 140 series diaphragm type pressure measurement

140 Series

Differential Pressure
Diaphragm Type
Up to 3000 PSIG