We vertical and uniform role in the unit area on the edge defined as the fluid pressure.

The formula is P= 1

In the formula : P The role of fluid pressure;

F Force;

A Role area.

In the International System of Units, the unit is the force F Newton (N), A role of the units are meters 2 (m 2), the unit is the pressure P N / m 2 that is Pascal (Pa).

In real life, and the production of a different concept of the pressure.

(1) atmospheric pressure: atmospheric pressure is on the air, in the Earth's surface by the weight of the pressure. PB with symbols that the atmospheric pressure of the meteorological conditions, geographic latitude and altitude change, and so different.

(2) Table pressure: pressure by the instructions of the instrument known as the pressure table pressure, it is the start of the atmospheric pressure to zero pressure. PG expressed by symbols. Table pressure is usually works in the practical pressure.

(3) absolute pressure: that is not attaching any conditions the start of the full pressure. That is, liquid, gas and steam room where all the pressure. It is atmospheric pressure and the pressure and the table. PA with symbols:

P A P G ʮ P B

(4) (4) reduced air pressure: When the pressure is less than atmospheric pressure, atmospheric pressure and the pressure is referred to as the difference between the reduced air pressure, known as vacuum pressure, negative pressure. With symbols P H said :

P H P B P A

(5) differential pressure (the pressure): the difference between the two related pressure, commonly used symbol P said.

Absolute pressure, pressure on the table, atmospheric pressure, vacuum pressure and the relationship between differential available under the plans said.

Chen, the concept of pressure, flow measurement also frequently used in the static, dynamic pressure concept:

(6) HIP: static means that the fluid flow in from the effect of pressure on the table measured value. For example: the pipe wall of the premises measured by the flow of pressure, both static value. The past to use liquid column that the high pressure known as the pressure head, said water to a higher Paper

HIP called hydrostatic head.

Absolute pressure, pressure on the table, atmospheric pressure and the relationship between real space

The distribution of the velocity

(7) dynamic pressure: fluid dynamic pressure is a unit volume by the size of kinetic energy. Usually 1 / 2 Ѧ 2 calculation.

In the formula ѡ Fluid density;

v Fluid velocity.

Dynamic pressure also known as the first dynamic pressure.

Fluid pressure from the various instruments of pressure. Instruments are commonly used spring-loaded pressure gauge, pressure gauge, and other liquids.

The pressure of fluid flow measurement is in a very important parameter. Pressure-flow meter is measured by cutting expenditure at both ends of

the pressure difference to achieve flow measurement. In addition to measuring the pressure flowmeter know the work pressure, the necessary amendments of

operator, to ensure that the flow measurement accuracy.