When you’re cutting fruit with a knife, the surface area of its edge is small, therefore, that creates a higher pressure to cut through the object. Similarly, when a vacuum cleaner is switched on, the fan installed inside it creates low pressure in the equipment which facilitates the inward pulling of any dirt particles inside the device.
In both these cases, you hear about the term called “pressure”.
When you’re cutting fruit with a knife, the surface area of its edge is small, therefore, that creates a higher pressure to cut through the object. Similarly, when a vacuum cleaner is switched on, the fan installed inside it creates low pressure in the equipment which facilitates the inward pulling of any dirt particles inside the device.
In both these cases, you hear about the term called “pressure”.
What is Pressure?
In Physics, pressure is defined as the force exerted perpendicularly per unit area. It is a scalar quantity and is denoted by the units Pascal (SI) which is equal to one Newton per square meter (N/m2, or kg·m−1·s−2). It can also be represented by the units atm, torr, bar, pound-force, etc.
The standard formula for pressure is p = F/A. Where F is the force applied and A is the area that bears it.
Hydrostatic pressure, also known as formation pressure or reservoir pressure is the pressure of fluids in a hydrocarbon reservoir, calculated on the basis of reservoir depth and the change in pressure according to it. It is commonly expressed in two major terms: Gauge pressure and absolute pressure.
In Physics, pressure is defined as the force exerted perpendicularly per unit area. It is a scalar quantity and is denoted by the units Pascal (SI) which is equal to one Newton per square meter (N/m2, or kg·m−1·s−2). It can also be represented by the units atm, torr, bar, pound-force, etc.
The standard formula for pressure is p = F/A. Where F is the force applied and A is the area that bears it.
Hydrostatic pressure, also known as formation pressure or reservoir pressure is the pressure of fluids in a hydrocarbon reservoir, calculated on the basis of reservoir depth and the change in pressure according to it. It is commonly expressed in two major terms: Gauge pressure and absolute pressure.
What is Gauge Pressure?
It is defined as the pressure difference between the reference object and the ambient atmospheric pressure (Patm). It is denoted by the subscript g after the pressure unit (Pg).
It is important to understand that atmospheric pressure is not constant at all times. Therefore, the comparative values that are measured are different in every time interval. When the gauge pressure is higher than the pressure in the ambient environment, it is termed as positive pressure and when it is lower than the same, it is referred to as negative or vacuum gauge pressure.
Gauge pressure sensors of pressure gauge like a manometer have a single port through which the atmospheric air pressure is directed to the back of it. The negative side of the pressure sensing diaphragm comes in contact with the exterior air pressure, thus always determining the relative pressure with respect to atmospheric pressure.
In a sealed gauge, the atmospheric pressure is trapped on the negative side of the diaphragm, thus setting a “zero point”. This mechanism is then applied to calculate the hydraulic pressure because, in that set-up, the variations in the atmospheric pressure will have little to no effect on the correctness of the sensor.
It is defined as the pressure difference between the reference object and the ambient atmospheric pressure (Patm). It is denoted by the subscript g after the pressure unit (Pg).
It is important to understand that atmospheric pressure is not constant at all times. Therefore, the comparative values that are measured are different in every time interval. When the gauge pressure is higher than the pressure in the ambient environment, it is termed as positive pressure and when it is lower than the same, it is referred to as negative or vacuum gauge pressure.
Gauge pressure sensors of pressure gauge like a manometer have a single port through which the atmospheric air pressure is directed to the back of it. The negative side of the pressure sensing diaphragm comes in contact with the exterior air pressure, thus always determining the relative pressure with respect to atmospheric pressure.
In a sealed gauge, the atmospheric pressure is trapped on the negative side of the diaphragm, thus setting a “zero point”. This mechanism is then applied to calculate the hydraulic pressure because, in that set-up, the variations in the atmospheric pressure will have little to no effect on the correctness of the sensor.
What is Absolute Pressure?
It is the total pressure that is the summation of gauge pressure and atmospheric pressure. One way to look at it is to imagine the concept of space, which has a vacuum and is devoid of any atmosphere; therefore, no air particles generate pressure in it. Thus absolute pressure is the pressure that can be observed in a set-up that has no matter. It is denoted by Pabs.
Therefore Pabs = Pg + Patm
When it is computed, the absolute zero pressure is used as a reference point. It can be better understood during the measurement of barometric pressure. To reach the zero point, a high vacuum will be secured behind the sensing diaphragm. Thus, if the process pressure connection of the absolute pressure transmitter is left open to atmospheric air, one can obtain the readings of the actual barometric pressure.
Absolute pressure sensors are used when one wants to measure the pressures that do not take atmospheric pressure into account. This ensures that there are no errors in the readings if the barometric pressure is altered.
It is the total pressure that is the summation of gauge pressure and atmospheric pressure. One way to look at it is to imagine the concept of space, which has a vacuum and is devoid of any atmosphere; therefore, no air particles generate pressure in it. Thus absolute pressure is the pressure that can be observed in a set-up that has no matter. It is denoted by Pabs.
Therefore Pabs = Pg + Patm
When it is computed, the absolute zero pressure is used as a reference point. It can be better understood during the measurement of barometric pressure. To reach the zero point, a high vacuum will be secured behind the sensing diaphragm. Thus, if the process pressure connection of the absolute pressure transmitter is left open to atmospheric air, one can obtain the readings of the actual barometric pressure.
Absolute pressure sensors are used when one wants to measure the pressures that do not take atmospheric pressure into account. This ensures that there are no errors in the readings if the barometric pressure is altered.
Gauge Pressure Vs Absolute Pressure
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