Method and apparatus for the determination of moisture content of fibrous and granular materials

摘要

A method, for the determination of moisture content of fibrous and granular materials, comprising bringing a sensitive element in contact with a fibrous or granular material under study. During the time of contact of the sensitive element with the material under study the sensitive element is subjected to preliminary pulse heating to between 40. degree. and 90° C., with subsequent main pulse heating to between 90° and 140° C. The moisture content of the material under study is evaluated by the time for the main heating of the sensitive element. An apparatus for carrying out the above method comprises main and auxiliary measuring bridge circuits having arms in which are inserted resistors and a sensitive element comprising a pulse heat emitter which forms a common arm of both bridge circuits. A selector switch is inserted in the common arm of the bridge circuits. A zero detector is inserted in the diagonals of the bridge circuits in such a manner that it receives a signal from one bridge circuit in one position of the selector switch and from the other bridge circuit in the other position of the selector switch. To the output of the zero detector is coupled an input of a control unit having its outputs coupled to the selector switch and to a recording instrument.