Patent ID: 6393729
Filing Date: 2002-05-28
Classification: F26B,G05D

Abstract:
Method for controlling process variables of a process gas (10) passing through a drying chamber, and which during the passage through said drying chamber is led adjacent to or through a product so that a substance is taken up by the process gas and the substance at least in part is removed from the product and transported away with the process gas out from the drying chamber, the process variables of the process gas flowing out from the drying chamber being controlled and monitored by monitoring and controlling a first group of process variables comprising content (x) in the process gas of the substance removed from the product and pressure conditions (z) inside the drying chamber are monitored and controlled, and in which one or more process variables forming part of a second group of manipulated process variables, comprising supply flow (a) and output flow (e) of the process gas are manipulated based on a change of one controlled process variable (x; z), wherein the content (x) of the substance removed from the product and the pressure conditions (z) inside the drying chamber are controlled independently of each other, the content (x) of the substance removed from the product being controlled by manipulating the process gas output flow (e), and the pressure conditions (z) being controlled by manipulating the process gas supply flow (a), the supply flow (a) being compensated for a change in the output flow (e).