Method of controlling drying of timber in a closed room

Claim 1

A method of controlling the drying of timber which comprises a. placing the timber in a closed drying chamber, sensing the humidity in the closed chamber and emitting an electronic signal in proportion to the thus sensed humidity, b. feeding the signal generated in step (a) to a comparator means having an upper and lower hysterisis level at its input and comparing the signal generated in step (a), which represents the actual humidity in the drying chamber, with an upwardly and downwardly adjustable nominal value for humidity which must not be greater than the value for the highest allowable humidity in the drying chamber, c. initiating ventilation of the drying chamber when the actual value of the humidity exceeds the nominal value valid at the moment in question plus the difference between said nominal value and the upper hysterisis level of said comparator means, d. discontinuing ventilation of the drying chamber when the actual humidity value in the drying chamber falls below the nominal value valid at the moment in question minus the difference between said nominal value and the lower hysterisis level of the comparator means, e. effecting further ventilation of the drying chamber when the actual value of the actual humidity in the drying chamber exceeds the nominal value at the moment in question plus the difference between said nominal value and the upper hysterisis level of said comparator means, f. repeating steps (d) and (e) any desired number of times, g. measuring the time elapsed between each cessation of ventilation and each subsequent initiation of ventilation, h. changing the aforesaid nominal value when the time measured in step (g) falls outside a certain time interval.

Claim 2

A method of controlling the drying of timber which comprises a. placing the timber in a closed drying chamber, sensing the humidity in the closed chamber and emitting an electronic signal in proportion to the thus sensed humidity, b. feeding the signal generated in step (a) to a comparator means having an upper and lower hysterisis level at its input and comparing the signal generated in step (a), which represents the actual humidity in the drying chamber, with an upwardly and downwardly adjustable nominal value for humidity which must not be greater than the value for the highest allowable humidity in the drying chamber, c. initiating ventilation of the drying chamber when the actual value of the humidity exceeds the nominal value valid at the moment in question plus the difference between said nominal value and the upper hysterisis level of said comparator means, d. discontinuing ventilation of the drying chamber when the actual humidity value in the drying chamber falls below the nominal value valid at the moment in question minus the difference between said nominal value and the lower hysterisis level of the comparator means, e. effecting further ventilation of the drying chamber when the actual value of the actual humidity in the drying chamber exceeds the nominal value at the moment in question plus the difference between said nominal value and the upper hysterisis level of said comparator means, f. repeating steps (d) and (e) any desired number of times, g. measuring the time elapsed between each cessation of ventilation and each subsequent initiation of ventilation, h. changing the aforesaid nominal value when the time measured in step (g) falls outside a certain time interval.

Claim 3

A method of controlling the drying of timber which comprises a. placing the timber in a closed drying chamber, b. sensing the humidity in the closed chamber, c. comparing the sensed humidity to a reference value, d. initiating ventilation of the drying chamber when a certain difference relationship exists between the sensed humidity and said reference value, e. discontinuing ventilation of the drying chamber when another difference relationship exists between the sensed humidity and said reference value, f. effecting further ventilation of the drying chamber when a certain difference relationship exists between the sensed humidity and said reference value, g. repeating steps (e) and (f) any desired number of times, h. determining the rate at which actual humidity in the drying chamber changes per unit of time during the interval between the cessation of ventilation and initiation of ventilation, and i. changing the reference value set forth in step (c) when the rate determined in step (h) falls outside a certain range.

Claim 4

A method of controlling the drying of timber which comprises a. placing the timber in a closed drying chamber, b. sensing the humidity in the closed chamber, c. comparing the sensed humidity to a reference value, d. initiating ventilation of the drying chamber when a certain difference relationship exists between the sensed humidity and said reference value, e. discontinuing ventilation of the drying chamber when another difference relationship exists between the sensed humidity and said reference value, f. effecting further ventilation of the drying chamber when a certain difference relationship exists between the sensed humidity and said reference value, g. repeating steps (e) and (f) any desired number of times, h. determining the rate at which actual humidity in the drying chamber changes per unit of time during the interval between the cessation of ventilation and initiation of ventilation, and i. changing the reference value set forth in step (c) when the rate determined in step (h) falls outside a certain range.

Claim 5

A method of controlling the drying of timber which comprises a. placing the timber in a closed drying chamber, b. ventilating said drying chamber in a manner which is dependent upon the relationship between the humidity in the chamber and a reference value, c. determining the rate of humidity change per unit of time during at least part of the time the timber is in the drying chamber, and d. varying the magnitude of the reference value used in step (b) when the rate determined in step (c) falls outside a certain range.

Claim 6

A method of controlling the drying of timber which comprises a. placing the timber in a closed drying chamber, b. ventilating said drying chamber in a manner which is dependent upon the relationship between the humidity in the chamber and a reference value, c. determining the rate of humidity change per unit of time during at least part of the time the timber is in the drying chamber, and d. varying the magnitude of the reference value used in step (b) when the rate determined in step (c) falls outside a certain range.