| 摘要 |
A draft safeguard apparatus for use in a multi-poised furnace having an inducer housing for receiving flue gases from a heat exchanger. The furnace flue pipe is attached to the inducer housing by an elbow that is rotatably connected to the inducer housing. An elongated sensor housing is mounted upon the elbow. The housing provides a flow channel so that the inlet section of the elbow communicates with the surrounding ambient. A limit switch is mounted in the housing to sense the temperature in the flow passing through the housing. When the furnace is operating normally, ambient air is drawn into the vent system through the sensor housing. If the vent system becomes restricted, the flow through the housing is reversed and the limit switch is opened when the reverse flow temperature exceeds a given limit. A baffle that includes a flat, rectangular-shaped top plate is mounted inside the elbow to form a chamber over the entrance to the sensor housing which directs the flue gas flow over the entrance when the vent system is unblocked and directs the flue gas flow into the gas sensor housing in the event that the vent system becomes blocked.
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