METHOD AND APPARATUS FOR THROTTLE VALVE CONTROL OF A CALENDER ROLL ACTUATOR

摘要

A throttle valve is provided in each actuator of a calender roll controller with the throttle valve controlling an internal air orifice within each actuator to provide a substantially uniform air mass flow of either hot or cold air. Each throttle valve is controlled in response to the temperature of the air being delivered by the actuator such that a smaller orifice is provided for hot air than for cold air to provide substantially uniform air mass flow from each of the actuators and therefore substantially uniform air velocity to better control the temperatures of the longitudinal zones of a calender roll and better maintain boundaries between the zones. In addition to throttle valve control of the actuators, an air scoop concentric with a calender roll being controlled and spaced from the calender roll is provided to channel air from the actuators over the calender roll. The scoop comprises heat insulating material to prevent heat loss out the back of the scoop. In addition, a plurality of arcuate zone strips are provided on the concave inner surface of the scoop and in substantial alignment with the plurality of actuators for channeling air from the actuators. The arcuate zone strips are spaced apart from one another for thermal separation such that thermal diffusion among longitudinal zones of a calender roll within the scoop are substantially eliminated.