1. Pressure Gauges & Pressure Reducing Valves By Ahmed Ibrahim ; M.D. Prof.of Anaesthesia Ain Shams University

2. Pressure Gauges Bourdon tube Metal diaphragm

3. Bourdon tube

4. Metal diaphragm

5. Pressure Reducing Valves

6. Aim is to give a flow which is, Steady Reduced Easy to transport through tubes

7. Reducing valve is either : One stage Simple Modified Inversed Two stages Demand

8. a & A of same wt ; with different areas At equilibrium; Force at a = force at A P x a = R x A R / P = a / A ; R = P x a / A

9. Simple type

10. FsFs P R At equilibrium ; R x A = F s + ( P x a ) Considering that “a” is too small –(negligible) ; F s = R x A Modified type

11. FsFs RP Inversed type At equilibrium; F s = ( RxA ) + ( Pxa ) As F s is constant ; P  1/ R

13. Thank you