| 摘要 |
An air heater for installation in a fireplace located in a room to be heated having a lower metalic portion having a hollow back wall surmounted by a flue portion also having a hollow back wall communicating with the hollow back wall of the lower portion so as to form a common heating chamber. The heating chamber has an opening at its lower end for receiving air to be heated from outside of the room in which the fireplace is located and has a plurality of ducts extending across the flue portion at the upper end of the heating chamber for permitting escape of the heated air into the room to be heated and a vent pipe extending from the upper end of the heating chamber to vent heated air outside of the room in which the fireplace is located. The air ducts and vent pipe are opened and closed by the operation of valves so arranged that when the air ducts are opened to the passage of air the vent pipe is closed and the vent pipe is open when the air ducts are closed.
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