1. Pressure A measure of the amount of force exerted on a surface area A measure of the amount of force exerted on a surface area

2. Displacement of Water The amount of water displaced is equal to the volume of the rock.

3. Bourdon gauge

4. The movement of the free end of the elliptical tube is proportional to the difference between "external and internal pressure on the tube. Since the outside pressure on the tube is atmospheric, the movement of the free end is a measure of the boiler pressure above atmospheric. The movement of the free end of the elliptical tube is proportional to the difference between "external and internal pressure on the tube. Since the outside pressure on the tube is atmospheric, the movement of the free end is a measure of the boiler pressure above atmospheric.

5. The pressure gauge is connected with the. Boiler’s steam space through a 'u' tube syphon. The U shape siphon pipe contains water, which fills the Bourdon tube. The pressure gauge is connected with the. Boiler’s steam space through a 'u' tube syphon. The U shape siphon pipe contains water, which fills the Bourdon tube. The pressure of the steam acting through the water on the inside of the tube tries to make the tube circular The pressure of the steam acting through the water on the inside of the tube tries to make the tube circular

6. One end is fixed, the free end moves. The movement of the free end is proportional to the difference' between "external and internal pressure on the tube Because of pinion and gear arrangement, the slide movement of the pressure gauge to the steam space. One end is fixed, the free end moves. The movement of the free end is proportional to the difference' between "external and internal pressure on the tube Because of pinion and gear arrangement, the slide movement of the pressure gauge to the steam space.

7. Bourdon tube is magnified considerably.and point gives maximum deflection, which can be read on the scale. The water in tube prevents the steam from coming in contact with the spring tube. These will reduce over heating and thermal stresses in spring tubes. Bourdon tube is magnified considerably.and point gives maximum deflection, which can be read on the scale. The water in tube prevents the steam from coming in contact with the spring tube. These will reduce over heating and thermal stresses in spring tubes.