Method and apparatus for measuring the size of a discharge slot in a headbox

Apparatus for directly measuring the distance across the stock discharge slot of a paper machine during the operation of the paper machine, said apparatus comprising stock-delivering means including a pair of cooperating structural members positioned in opposed spaced apart relation and defining a stock discharge slot therebetween, ultrasonic transducer means mounted in one of said structural members and arranged to transmit an ultrasonic pulse through the stock passing between said cooperating structural members and to the oppositely positioned structural member, and an electronic measuring unit connected to said ultrasonic transducer means and operable to measure the travel time of the ultrasonic pulse across the slot defined between said structural members, from which can be determined the distance between said structural members.

Apparatus for directly measuring the distance across the stock discharge slot of a paper machine during the operation of the paper machine, said apparatus comprising a headbox including cooperating upper and lower lip members positioned in opposed relation to one another and defining a stock discharge slot therebetween, ultrasonic transducer means mounted in one of said lip members and arranged to transmit an ultrasonic pulse through the stock passing between said cooperating lip members and to the oppositely positioned lip member, and an electronic measuring unit connected to said ultrasonic transducer means and operable to measure the travel time of the ultrasonic pulse across the slot defined between the two lip members, from which can be determined the distance between said two lip members.

A method for directly measuring, during the operation of a paper machine, the distance between a pair of cooperating lip members positioned in opposed spaced apart relation to one another and defining a stock discharge slot therebetween, said method comprising transmitting an ultrasonic pulse from one of the lip members through the stock passing between the cooperating lip members and to the oppositely positioned lip member, measuring the travel time of the ultrasonic pulse through the stock to said oppositely positioned lip member, and converting the measured travel time of ultrasonic pulse into the distance between the two lip members.

Apparatus for directly measuring the distance across the stock discharge slot of a paper machine during the operation of the paper machine, said apparatus comprising a multilayer headbox including cooperating upper and lower lip members positioned in opposed relation to one another and defining a stock discharge slot therebetween, and including two channel-portion-forming partitions arranged between said upper and lower lip members and defining three smaller discharge slots between said upper and lower lip members, two ultrasonic transducer means arranged in one of said partitions and oriented for measuring to one of said lips and to the other partition, respectively, and including an ultrasonic transducer means in said second partition arranged for measuring to said other lip.

Apparatus for directly measuring the distance across the stock discharge slot of a paper machine during the operation of the paper machine, said apparatus comprising a multilayer headbox including cooperating upper and lower lip members positioned in opposed relation to one another and defining a stock discharge slot therebetween, and including at least one stock-separating partition member located between said lip members, said at least one partition member being too thin to permit mounting of ultrasonic transducer means therein, and including two ultrasonic transducer means mounted in the other lip, the thin partition located nearer said one lip being provided with a through hole arranged exactly opposite one of said two ultrasonic transducer means to permit passage through this hole of a transmitted ultrasonic pulse.