Presentation on pressure measurement.

1. Pressure Measurements
Submitted by:
MOHD ATIF
B.TECH(I.N.)
III YEAR
10231022

2.  INTRODUCTION
 UNITS OF PRESSURE
 CLASSIFICATION OF PRESSURE MEASUREMENT

3. INTRODUCTION
Pressure means force per unit area, exerted by a
fluid on the surface of the container.
P=F/A
F - FORCE (in Newton)
A - AREA (in meter²)
Pressure is of two types-
STATIC PRESSURE
DYNAMIC PRESSURE
WHERE,
F

4. Pressure is of two types-
1- STATIC PRESSURE
2- DYNAMIC PRESSURE
STATIC PRESSURE- when the force in a system
under pressure is constant or static (i.e. unvarying),
the pressure is said to be static pressure.
DYNAMIC PRESSURE- If the force is varying, on
the other hand, the pressure is said to be dynamic
pressure.

5. 1 atm = 14.7 Psi at sea level
= 101.3 Kilo Pascal
= 760 mm of Hg
= 10.3 m of water
= 1013 mili bar
1 Pascal = 1N/m2
1 Bar = 100 Pascal

6. MECHANICAL ELECTROMECHANICAL
STATIC DYNAMIC(Force Summing Devices)
MANOMETER
U-TUBE
WELL TYPE
INCLINED
DIAPHRAM BELLOWS BOURDON-TUBE
CLASSIFICATION OF PRESSURE MEASUREMENT
FLAT CORRUGATED CAPSULE
C-TYPE HELICAL
TYPE
SPIRAL
TYPE

7. ELECTROMECHANICAL
POTENTIO
METER
PHOTOELECTRIC
TYPE
CAPACITIVE PIEZOELECTRIC
TYPE
INDUCTIVE

9.  This manometer consist of U-
shaped tube in this manometric fluid
is filled.
 Water and mercury are used as a
manometric fluid.
 Advantage of using these fluid is
that mass density of these fluid can
be obtained easily and they do not
stick to the tube.

10. Since, P = ρgh
h = (P₁ - P₂)/ρg
P₁ - P₂ = ρgh
Where, ρ - mass density of fluid
g - gravity
P₁ - unknown pressure
P₂ - atmospheric pressure

12. The well type manometer is widely
used because of inconvenience; the
reading of only a single leg is required in
it.
It consist of a very large-diameter vessel
(well) connected on one side to a very
small-sized tube.
Thus the zero level moves very little
when pressure is applied.

14. The force summing devices are those which
converts the applied pressure into
displacements by primary transducers while
generated displacements may be measured by
secondary transducers.
The commonly used force summing devices
are-
1- DIAPHRAGM
2- BALLOWS
3- BOURDON TUBE

15. Diaphragm are widely used for pressure
(gauge pressure), particularly in very low
ranges. They can detect a pressure differential
even in the range of 0 to 4mm.
The diaphragm can be in the form of Flat,
Corrugated and Capsules the choice depends
on the strength and amount of deflection
required.

17. A bellows gauge contains an
elastic element that is a
convoluted unit that expands
and contracts axially with
change in pressure.
The pressure to be measured
can be applied to the outside or
inside of the bellows however,
in practice, most bellows
measuring devices have the
pressure applied to the outside
of the bellows.

18. An elastic transducer , that is
bourdon tube which is fixed and
open at one end to receive the
pressure which is to be measured.
The other end of the bourdon tube
is free and closed.
The bourdon tube is in a bent
form to look like a circular arc.
All the various form of bourdon
tube have the common feature
that they are constructed the tube
of non circular cross-section