To provide a web heating system for a paper machine dryer, having such a scheme that superheated steam is used as the heating medium for webs and made reusable after used once with the help of a circulatory system and the steam concentration in the circulatory system is kept constant by controlling the air partial pressure of a circulating gas at a constant level, thus the webs are heated with minimal energy consumption and the high-speed stability of the dryer is improved, further, water hammering of the circulatory system inside pipings is suppressed to stably operate the web heating system.
The web heating system for the paper machine dryer is constituted such that a temperature-raising section hood 127 and a mist tank 201 storing a saturated wet air are connected with each other, the temperature in the mist tank 201 is adjusted to a prescribed level by thermoregulatory means 212 and 223 while the pressure in the mist tank 20 is adjusted to a prescribed level by pressure regulatory means 208 and 222, thus the air partial pressure of the wet air in the mist tank 201 is controlled at a constant level, thereby affording the stable steam circulatory system without causing any water hammering in the pipings in the system.
SUZUKI SETSUO
KONO SUSUMU