Upon a change in the thermal load in the mains, the pressure acting on regulator 1 changes so that the membrane is bent up or down. This turns lever 2 and shifts the spool of valve 3. Hydraulic fluid, delivered to the valve, is directed to servomotor 4, moving piston 5 and regulating member 6 in the required direction. This changes the amount of steam supplied to the turbine. A change in turbine shaft speed actuates centrifugal governor 7, which shifts the spool of valve 3 through levers 8 and 9. Fluid from valve 3 is delivered to servomotor 4, whose piston 5 either opens or closes valve member 6, which regulates the supply of steam to the turbine.
$4228$CHP,Rg$