PURPOSE: To stably control the humidity in a drier by controlling the inner pressure of a hood without causing response delay in the paper-drying process of a paper machine.
CONSTITUTION: The control device of a paper machine hood 1 disposed in a drier for drying wet paper in the paper machine and having an exhaust fan 10 for controlling the humidity and an air supply fan 4 for controlling the pressure is provided with a means 15 for converting the signal of the rotational speed of the exhaust fan 10 into the volume of the exhaust flow, a multiplier 18 for multiplying the converted flow volume value of the exhaust fan by a constant number determined by the difference between the ability of the exhaust fan and the ability of the air supply fan, and means 16, 7 for converting the air supply fan flow volume computed with the multiplier into the rotation number signal of the air supply fan and subsequently controlling so that the volume of the exhaust flow is almost equal to the volume of the supplied air flow.
ISEKI MASAYUKI
OKUBO ISAMU
YOKOGAWA ELECTRIC CORP