Abstract: The method utilizes a known good set of moisture content data for wood dried in a kiln under set conditions to estimate parameters for a Lognormal distribution which approximates the moisture content data for those conditions. The method creates control charts which monitor some of these parameters. The method also takes data from subsequent kiln charges and transforms it to be represented on the control charts. The method uses this representation to determine if the kiln is operating under out-of-control conditions.

Abstract: A kiln controller controls the drying of lumber in a kiln by executing a drying schedule and adjusting the drying schedule in response to actual measured conditions in the kiln. A computer within the controller controls heating coils, spray nozzles and vents in the kiln to achieve the conditions prescribed in the drying schedule. The computer first executes a routine whereby the kiln temperature is brought up to a desired initial temperature. Then the computer concurrently executes the drying schedule and a routine wherein it monitors the temperature, vent load and spray nozzle activity, and automatically adjusts the duration of the current step in the drying schedule.