Why is a check valve installed on the feed water pipeline before the economizer?

Reply to 1# zgj2405: To prevent the boiler water from flowing back into the feedwater system in the event of a feedwater interruption.

This post was last edited by dongjiang1001 on 2011-6-21 20:36. The purpose of installing check valves in the feed water pipeline of the economizer is to prevent water from flowing in the reverse direction from the steam drum or economizer in case of a failure in the feed water pump or feed water pipeline; otherwise, such backflow could cause a shortage of water in the economizer and water wall, leading to damage. The purpose of installing a recirculation pipe and a recirculation valve between the economizer inlet and the steam drum is to ensure the safety of the economizer. When the boiler is started, shut down, or when water supply is interrupted for other reasons, the water inside the economizer stops flowing and thus cannot be cooled, which may lead to overheating of the tube walls and damage to them. When the water supply is interrupted, the recirculation valve is opened, creating a circulation loop between the steam drum, the recirculation pipe, the economizer, and back to the steam drum, thereby ensuring continuous cooling of the economizer’s tube walls.

This post was last edited by dongjiang1001 on 2011-6-22 at 20:44. The purpose is to prevent backflow of water when the boiler runs out of water, thereby avoiding the boiler from drying up； The second is to protect the feed water pump.

The purpose of installing check valves in the feed water pipeline of the economizer is to prevent water from flowing in the reverse direction from the steam drum or economizer in the event of a failure in the feed water pump or feed water pipeline; otherwise, such backflow could cause a shortage of water in the economizer and water wall, leading to damage.

Is it to be installed at the inlet or the outlet of the economizer? According to the explanation, it should be at the outlet