Pressure measuring equipment
What is pressure?
Pressure is defined as the amount of vertical force applied per unit area.

Pressure is a scalar quantity (numerical) and establishes a relationship

between two quantities of force and surface. The pressure is defined as follows.

                                                                                                                      (Force (F)) / (level (A)) = (P) pressure

Pressure is directly related to force and inversely related to cross section;

Assuming the same force, the higher the cross-sectional area, the lower the pressure per unit area, and vice versa.

Pressure is generally the amount of force applied to a given surface. In the case of a liquid

or gas that is static and motionless, pressure is the amount of force applied to the wall of a liquid or

gas holding chamber at a specific point and is defined in two ways.

Static Pressure: Static pressure is the same in all directions.

Dynamic Pressure: A fluid that is moving exerts an

 excess pressure in the direction of the fluid. This excess pressure is

 called dynamic pressure.
Static pressure is always present, but the body must

move relative to the fluid to create dynamic pressure.
Total pressure is the sum of static pressure and dynamic

pressure and is also known as effective pressure or static pressure.

                                                    Total pressure = static pressure + dynamic pressure
Measures the amount of total pressure when an instrument is positioned in the direction of fluid flow or flow.
Pressure is generally measured in three types: absolute pressure, gauge pressure,

and differential pressure, each with its own definition.
Absolute pressure
Expresses the total amount of force per unit area. Absolute pressure is the pressure measured relative

to the absolute vacuum and its units of measurement are displayed as bara or psia.
Relative pressure or Gauge pressure
Most pressure gauges display this type of pressure. Which is the measured pressure relative to atmospheric pressure.

This means that the gauge pressure is equal to the absolute pressure plus the atmospheric pressure
                                                                                      Gage pressure = absolute pressure + atmospheric pressure
Therefore, the criterion of relative pressure is the measurement of pressure relative to sea level.

Its units of measurement are displayed as barg or psig. There are two types of measuring equipment for relative pressure or gauge pressure
Vacuum pressure measuring equipment: We use this equipment when we want to measure pressure less than atmospheric pressure.
Compound pressure measuring equipment These devices are able to measure less pressure and more pressure from the atmosphere at the same time.
Differential pressure
Simply put, differential pressure is the pressure difference between two points

. The unit of measurement is displayed in bard or psid.
Differential pressure measuring devices, including pressure gauges,

have two inputs and are in contact with the fluid at two points.
Relationship between types of pressure
Unit of pressure measurement
Pressure has different units in different systems and parts of the world.

The unit of pressure in the SI system is Pascal and one Pascal is equal to one Newton (N) per square meter (m2) and

is denoted by the symbol Pa.However, from 1971 onwards, the unit of pressure

in the SI system is expressed in Pascals, and before 1971, the unit of pressure in Newtons per square meter was common.