I am looking for 3 element boiler drum level control logic diagram and explanation ...
Posts: 14,118
Threads: 61
Joined: Oct 2014
The feed water control system is a three element type, designed to monitor changes in steam flow, water flow, and drum level. Steam flow is the rate of steam coming out of the boiler - demand. The flow of water is the flow rate of feed water into the boiler - the supply. The drum level reflects the amount of water in the boiler - the inventory. With changes in boiler load (steam flow), the flow of steam and water becomes unbalanced and the water level deviates from the normal position. In such a case, the system changes the flow of water to the extent necessary to restore the balance between the steam flow and the feed flow and return the water level to normal.
The diagram is given below: