초록 ▼

Lumber is dried in a kiln by controlling the temperature and humidity of air within the kiln during a first cycle, followed by a second cycle allowing humidity to equalize between the coarse and dense lumber in the kiln without adding further energy. Air recirculates across the lumber in the kilm, a

Lumber is dried in a kiln by controlling the temperature and humidity of air within the kiln during a first cycle, followed by a second cycle allowing humidity to equalize between the coarse and dense lumber in the kiln without adding further energy. Air recirculates across the lumber in the kilm, and the drop in dry bulb air temperature across the lumber indicates the dryness of the lumber. The air temperature within the kiln is maintained at a predetermined setpoint, but no attempt is made to control the temperature drop across the lumber. Upon reaching a predetermined temperature drop across the lumber, corresponding to a relatively high amount of moisture in the kiln, no further energy is supplied to the kiln and air recirculation continues for a time to allow equalization of moisture in all lumber within the kiln. The process yields a desired uniform amount of moisture in the lumber while avoiding overdrying of the relatively coarse lumber in the kiln.

대표청구항 ▼

Method of drying a quantity of green lumber of nonuniform density to a desired level of moisture content, comprising the steps of: placing a quantity of lumber of nonuniform density into a region; circulating the air within the region across the quantity of lumber; adding energy to the region, so as

Method of drying a quantity of green lumber of nonuniform density to a desired level of moisture content, comprising the steps of: placing a quantity of lumber of nonuniform density into a region; circulating the air within the region across the quantity of lumber; adding energy to the region, so as to remove moisture from the lumber; monitoring the dry bulb temperature drop in air flowing across the lumber without attempting to control that temperature drop, so as to determine the occurrence of a certain temperature drop corresponding to a predetermined compliance point indicative of a moisture content greater than the desired moisture content for the lumber; in response to reaching the compliance point, discontinuing the addition of drying energy to the circulating air; and thereafter continuing to circulate the air across the lumber while maintaining a temperature set point in the region for a predetermined time to allow equalization of moisture content to the desired dryness for the entire quantity of lumber, whereby the lumber reaches the desired degree of moisture content without overdrying the relatively less-dense lumber.