Manometer

Manometers are Passive instruments that give visual indication of pressure values. They are not common as they used to be because the new development of fast respond, easier and smaller pressure sensor.

Types;

There are three types of manometers.

A.    U-tube manometer

B.    Well-type manometer

C.    Inclined manometer 

A manometer is piece of Tube (Glass/Plastic) filled with liquid of known density and a scale for Measuring Distance.  Manometer used for low pressure measurement

U-tube manometer

U-tube type manometer

U-tube manometer is the most common form of manometer. U-tube manometer consist a U-shaped glass tube filled with liquid. When there are equal pressures on both sides, the liquid level shown zero-point on Scale. When the pressure applied on one side of u-tube then the liquid level raise on other leg. The difference in height of both columns of liquid compensate for the difference in pressure.

Pressure is read on scale as the difference in height (h) between two liquid columns.

U-tube manometer is used to measure gauge and differential pressure.

P = pgh

P = Pressure

G = acceleration of gravity

h = liquid height

ρ = U-tube liquid density

Well-type manometer

Well-type manometer;

Well-type manometer or cistern manometer is similar to U-tube type manometer but one column of tube made very large so that it forms a well. In Well-type manometer the liquid level is only one tube has to be measured. So that’s makes the instruments much easier than U-tube manometer.

Well-type manometer

Inclined manometer;

Inclined manometer

Inclined manometers are used to measured low pressures. Due to inclined of low pressure arm so the liquid has no longer distance to travel in a vertical tube on same pressure.