Description
Most gauges calculate the pressure relative to atmospheric pressure as the zero point. Hence, this form of reading is known as gauge pressure. Pressure gauges are analog as well as digital.
The pressure difference between the system and the atmosphere is given by the formula:
P=Pa+ ρgh
Where,
P= pressure at any point
Pa = atmospheric pressure
From this, we can make out that the pressure at any point is always greater than the atmospheric pressure by ρgh amount.
When P-Pa=ρgh
Where,
P =pressure of the system
Pa=atmospheric pressure
(P-Pa) = pressure difference between the system and atmosphere.
hρg = Gauge pressure
The difference between two pressures measured using the gauge is known as gauge pressure.
Bourdon Tube Pressure Gauge
A bourdon tube is the most commonly used pressure gauge. It is a mechanical instrument that measures the pressure without an electric supply. It is made of steel to resist wear and corrosion. A bourdon tube pressure gauge can measure pressure from 0.6 to 7000 bar (8 to 10000 psi). It is compatible with liquid or gaseous media for vacuum, as well as low and high-pressure applications. It is a compact instrument that is ideal for heavy vibration application and dynamic pressure load.
