WHAT IS PRESSURE ? PRIMARY ELEMENT OF PRESSURE.

RIDHAM SHAH

What is Pressure?

Pressure can be defined as “ The amount of force applied to surface per unit per area “

Units of pressure :

  • Kg/cm^2
  • Bar
  • PSI(pounds per square inch )
  • Pascal
  • mmH20 or mmwc
  • mmHG
  • InH2O
  • InHg

Important Conversion:

  • 1 kg/cm^2 = 14.223 PSI
  • 1 Bar = 14.504 PSI
  • 1 kg/cm^2 = 0.9807 Bar
  • 1 Bar =100000 pascal
  • 1 kg/cm^2 = 10018mmH2O
  • 1 Bar =1000 mBar

Types of the primary element

  1. Bourdon tube
  2. Diaphragm
  3. Bellow
  4. Strain gauge
  5. Peizoelectric senosre


1. Bourdon tube:






The bourdon tube is a tube that is constructed such that one end is open with the other end is closed.

The cross-section area is elliptical so that when pressure is applied to the open end, a displacement of the closed-end or tip is caused.
Bourdon tubes are typically construction of bronze, stainless steel, or other alloys depending on the fluid application.

Bourdon tube can measure pressure up to 29 bar(2900kpa), however, they are not accurate for the pressure of less than up to 0.3bar

Types: c type, spiral, helical


2.  Bellows:






The bellows is basically a convoluted can with an opening on one side and that being fixed.

Pressure is applied internally causing the bellows to expand and this motion is utilized in the pressure instrument.

When the pressure is relieved, the bellows return to this original position.

Bellows are usually made of brass, bronze, or stainless steel, however, for certain applications, various alloys can be used.
Bellows are typically a low-pressure element of up to 7 bar


3. Diaphragm:






The Diaphragm is a flexible disk that has pressure applied to one side, causing a deflection of the diaphragm.

When pressure is relieved, the diaphragm returns to its original position.
The displacement of the diaphragm is detected by the instrument for it is the primary element.


4. Piezoelectric sensor :






It is based on the principle that when a quartz crystal is compressed an electrical potential is produced.

This electrical potential is proportional to the pressure applied and is measured by an electronic circuit.

-----------------------------------------------------------------------------------------------------------------------------

Hope you would get good information from this article.  If you have any questions or quarry, Write it in the Comment box.If you find this article useful, Don't forget to share with your friends, engineers, students. 


Related Article

4.  




Post a Comment

0 Comments