Swelling & Shrinkage Effect in boiler drum || How To control carryover

Steam flow from the boiler is controlled by the downstream process (e.g. a turbine). ... These combined reactions will cause the level in the steam drum to increase or decrease rapidly. The increase and decrease in the water level caused by the pressure change are commonly referred to as the swell and shrink reactions. THIS PHENOMENON IS KNOWN AS SWELLING WHICH LEADS TO CLOSURE OF AUTOMATIC WATER CONTROL VALVE AND WATER STOP ENTERING THE BOILER. ... NOW AUTOMATIC WATER LEVEL CONTROL VALVE OPENS AND COOL WATER ENTERS THE SYSTEM AND BUBBLES BURST LEADING TO DECREASE IN LEVEL OF WATER MORE. THIS EFFECT IS CALLED SHRINKAGE.