Difference between Gauge Pressure and Absolute Pressure
Gauge Pressure |
Absolute Pressure |
---|---|
Gauge pressure is defined as the pressure relative to barometric or atmospheric pressure. | Absolute pressure is defined as the pressure of having no matter inside a perfect vacuum of space. |
It doesn’t take atmospheric pressure into account. It is equal to Absolute pressure minus atmospheric or ambient pressure. | It is the addition of atmospheric pressure and gauge pressure. It is used for the calculation of atmospheric pressure |
It uses atmospheric pressure (14.7 PSI) as its Zero point. | Calculations that took in absolute pressure and use this absolute zero as their reference point. |
It cannot be used in gas law calculations as it doesn’t reflect accurate pressure but rather a difference in pressure. | It gives accurate barometric or atmospheric pressure when sealed in a high vacuum behind the detecting diaphragm. |
It is greatly influenced by changes in altitude or weather conditions in atmospheric pressure. | It doesn’t get influenced by any external changes in atmospheric pressure. |
Formula of Gauge pressure is given by, pg = ps – patm , (Where pg is gauge pressure, ps is system pressure and Patm is atmospheric pressure) |
Formula of Absolute pressure is given by: pa = pg + patm (Where pa is absolute pressure, pg is gauge pressure and Patm is atmospheric pressure) |
It is used in machines like Well pumps, Air compressors, and Tire gauges. | It is used for leak testing in a totally sealed container, smartwatches, and navigation systems for altimeter measurements. |
A manometer is a device used to measure the gauge pressure. | Mercury Barometer is the device used to measure atmospheric pressure. |
Difference Between Gauge Pressure and Absolute Pressure
Pressure is the force per unit area applied toward a course perpendicular to the outer layer of an item. Numerically, it is represented with a ‘P’. To keep it precise, it is an amount of force following up on a unit area. The simple equation for pressure is P = F/A where P is Pressure, F is Force, and A is Area.
The SI unit for pressure is measured in Pascals (Pa). Other non-SI units are bar and PSI. There are two types of references to quantify pressure,
- Gauge Pressure
- Absolute Pressure
Table of Content
- Gauge Pressure
- Absolute Pressure
- Difference between Gauge Pressure and Absolute Pressure
- Sample Questions
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