BOILER IS PROVIDED WITH TWO INDEPENDENT MEANS OF FEED WATER SUPPLY TO BOILER. ONE IS MAIN FEED WATER LINE AND OTHER IS AUXILIARY FEED WATER LINE. THE MAIN FEED WATER LINE HAS AN AUTOMATIC FEED WATER VALVE WHICH OPENS AND SHUTS WITH THE DEMAND OF WATER.
EACH LINE CONTAINS TWO VALVES, OUT OF WHICH THE ONE CONNECTED DIRECTLY TO THE BOILER IS A SCREW LIFT VALVE WHILE THE OTHER IS A SCREW DOWN NON RETURN VALVE.
THIS ARRANGEMENT HAS FOLLOWING BENEFITS :-
- SCREW LIFT VALVE IS NOT USED TO CONTROL THE FLOW OF THE FEED WATER AND HENCE NO WIRE DRAWING HAPPENS AND CAN BE USED FOR ISOLATING THE BOILER FEED LINE.
- SCREW DOWN NON RETURN VALVE IS USED TO CONTROL THE FLOW OF FEED WATER.
- IF A FEED LINE JOINT BLOWS THEN SDNR VALVE CAN BE SHUT AND PREVENT BOILER CONTENT BEING DISCHARGED.
- TWO FEED CHECK VALVES WILL GIVE DOUBLE ISOLATION TO THE FEED LINE.