| 摘要 |
<p>PURPOSE:To conserve power cost by facilitating the control of the concn. of exhaust gas, by providing the passage change-over value of an exhaust gas passage, a branched exhaust gas passage and exhaust fans different in a size while controlling the rotation speeds of the exhaust fans by the signal of a gas concn. detecting alarm device to open and close the valve provided to an open air intake port corresponding to the amount of exhaust gas. CONSTITUTION:Fumigation gas in a fumigation chamber 1 reaches a passage change- over valve 13 through an opening and closing valve 5 and an exhaust passage 7 and mixed with the open air from a dilution air supply apparatus 10 in a mixing chamber 6 to reduce the concn. thereof to a prescribed concn. or less while the diluted gas is exhausted from a chimney 11. High concn. gas, directly after exhaustion is started, is exhausted by a small exhaust fan 15a and, when an exhaustion process advances and the gas in the chamber is diluted with air from the opening and closing valve 3 of an open air intake port 2 and a tolerant exhaustion amount increases, the passage change-over valve 13 is changed over to exhaust the gas by a large exhaust fan 15A. The rotation speed of the exhaust fans 15A, 15B is controlled by the signal of a gas concn. detecting alarm 12 and the opening degree of the opening and closing valve 3 is altered by a timer.</p> |
