| 摘要 |
PROBLEM TO BE SOLVED: To provide a fitting capable of forming an opening area of a ventilation flue in a predetermined size regardless of differential pressure of air pressure, by manually rocking and holding a ventilation valve which rocks over an upward attitude of opening the ventilation flue and a downward attitude of closing the ventilation flue by the differential pressure of the air pressure, at the upward attitude of a predetermined rocking angle.SOLUTION: A ventilation valve 5 is vertically rockably installed in a ventilation flue 4 of an upper horizontal frame member 20 over an upward attitude of opening the ventilation flue 4 and a downward attitude of closing the ventilation flue 4 by a differential pressure of air pressure of its ventilation flue 4, and a ventilation valve operation part 6 is installed in the upper horizontal frame member 20 so that the ventilation valve 5 can be rockably held in the upward attitude of the predetermined rocking angle by a ventilation valve rocking part 6b by manually operating its operation part 6c, and the opening area of the ventilation flue 4 can be formed in a predetermined size regardless of the differential pressure of the air pressure. |
