| 摘要 |
PROBLEM TO BE SOLVED: To make a boiler feed pump(BFP) continue to be operated continuously with safety or stopped with safety. SOLUTION: Temperature detectors 30, 31 are disposed at a BFP entrance 50 and at a BFP exit 51, respectively. A temperature Tin which is a temperature of water that flows into a BFP 10 and a temperature Tout which is a temperature of water after temperature rise in the BFP, are inputted to a BFP recirculation protection device 60. The device 60 determines whether a temperature rise valueΔT (=Tout-Tin) equals to or higher than a specified temperatureΔT2, and in a state ofΔT>ΔT, an interlock for fully opening a BFP recirculation valve is operated to suppress temperature rise in the BFP and continue the operation of BFP. When a BFP flow rate Qf is further lowered by some factor in a state where a BFP recirculation valve 15 is fully open, temperature rise in the BFP continues. When the temperature rise valueΔT exceeds a specified temperature valueΔT1, an interlock for stopping BFP is operated, and thus the BFP is safely stopped prior to the temperature rise up to a limit temperatureΔT0.
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