4. Figure 4.6 a) U-tube Manometer b) Well-type Manometer (a) (b)

6. Figure 4.7 Dead Weight Tester

7. - The gauge to be tested is installed and the piston is inserted in the cylinder. - The pressure exerted on the fluid by the piston is now transmitted to the gauge when valve is opened. - This pressure may be varied by adding weights to the piston or by using different piston-cylinder combinations of varying areas. - The viscous friction between the piston and the cylinder in the axial direction may be substantially reduced by rotating the piston-weight assembly while measurement is taken

10. Figure 4.8 Bourdon Tube

11. - The linkage is constructed so that the mechanism may be adjusted for optimum linearity and minimum hysteresis as well as compensate for wear which may develop over a period of time. - An electrical-resistance strain gauge may also be installed on the bourdon-tube to sense thr elastic deformation.

13. Figure 4.9 (a) Diaphragm and (b) Bellows (a) (b)

15. Figure 4.10 Various types of pressure gauges