Piezometer , U - tube manometer , Micromanometer

Piezometer :

- It is one of the simplest from of manometer .

- It consists of a glass tube , inserted in the wall of a container or of a pipe .

- The rube extends vertically upward to such a height that liquid can freely rise in it without overflowing  .

- The Pressure at any point in the liquid is indicated by the height of the liquid in the tube above that point.

- the Pressure at point a is given by P = (rho) *g*h

where:

rho = density of the given liquid in the tube  ,

g = acceleration gravity

h = height of the liquid in the tube .  

U-tube manometer :

- it consist of a U-shaped glass tube , the one end of which is connected to a point at which pressure is to be measured and the other end remain open at the atmosphere .

- the u-shaped of the tube enables the manometer to measure pressure of both liquid and gases with same instrument .

- the tube is filled with the fluid called as manometric fluid ( reference fluid ) .

- the fluid whose pressure is to be measured should be lighter i.e. it should have a mass density less then that of the manometric fluid  .

P = (rho)*g*h 

where :

rho =  density of the reference fluid  .

g = acceleration gravity

h = height of liquid in the tube . 

Single Column manometer ( Micromanometer ) :

- it is modified form of a u-tube manometer .

- there is one reservoir with large cross-sectional area about 100 times as compared to the area of glass tube .

- One limb of glass tube is connected with the reservoir and another limb of glass tube is open at atmosphere .

- Pressure is measured at a point in the fluid by connecting the manometer with the container filled with liquid whose pressure is to be measured . ( light liquid ) . rise of liquid in the tube will provide the pressure head .

Vertical single column manometer :

X  -  initial level of heavy liquid .

Y - level of heavy liquid after connecting to the liquid .

P = h2(rho2)g - h1(rho1)g

Inclined single column manometer :

X - initial level of heavy liquid 

Y - level of heavy liquid after connecting to the liquid  .

P = sin0 X (rho2)g - h1(rho1)g