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

Pressure Gauges Bourdon tube Metal diaphragm

Bourdon tube

Metal diaphragm

Pressure Reducing Valves

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

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

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

Simple type

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

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

Thank you