s.

P1.18 A cutaway view of a commonly used pressure reg-

ulator is shown in Figure P1.18. The desired pressure

is set by turning a calibrated screw. This compresses

the spring and sets up a force that opposes the up-

ward motion of the diaphragm. The bottom side of

the diaphragm is exposed to the water pressure that

is to be controlled. Thus the motion of the diaphragm

is an indication of the pressure difference between/n44 Chapter 1 Introduction to Control Systems

Diaphragm

(area A)

Input

flow

Valve

wwww

Pressure

adjustment

screw

Spring

FIGURE P1.18 Pressure regulator.

Output

flow