To provide an excessive negative pressure protection device for a boiler capable of avoiding pressure inside a boiler from becoming an excessive negative pressure without stopping an induced draft fan.
The protection device is equipped with a protection device body provided to communicate with an induced flow passage between a boiler and the induced draft fan and which has an opening portion communicating with the inside and the outside of the induced flow passage, a lid member for opening/closing the opening portion of the protection device body, and a spring member for energizing the lid member to the closing side of the opening portion. When the negative pressure inside the induced flow passage becomes a certain amount or more, the lid member resists the energizing force of the spring member and opens the opening portion by its negative pressure.
MATSUI AKIRA
YAMAGATA SHIGEO
Takao Ito
Jiro Higuchi
Muramatsu Toshiro
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