Apparatus for measuring and recording basis weight of paper and the like

Claim 1

APPARATUS FOR CONTINUOUSLY MEASURING AND INDICATING THE BASIS WEIGHT OF A MOVING SHEET OF PAPER DURING THE MANUFACTURE THEREOF, COMPRISING A SENSING STATION INTERPOSED IN THE PAPER MANUFACTURING PRODUCTION LINE THROUGH WHICH THE PAPER SHEET PASSES, AN INCANDESCENT LAMP LOCATED ON ONE SIDE OF THE PAPER SHEET AT SAID SENSING STATION WHICH EMITS A BEAM OF ELECTROMAGNETIC RADIATION HAVING A SPECTRAL RANGE SUBSTANTIALLY SPANNING PART OF THE VISIBLE SPECTRAL REGION AND EXTENDING INTO THE NEAR INFRARED REGION INCLUDING A SELECTED WAVE LENGTH BAND WHICH IS SUBSTANTIALLY UNAFFECTED BY THE MOISTURE CONTENT OF THE PAPER SHEET BUT WHICH IS MODULATED BY VARIATIONS IN THE PULP STRUCTURE, OPTICAL MEANS FOR DIRECTING SAID BEAM ALONG A SELECTED PATH THROUGH THE MOVING PAPER SHEET, OPTICAL FILTER MEANS IN THE PATH OF SAID BEAM OF CONFINING THE SAME TO SAID SELECTED WAVE LENGTH BAND, PHOTOELECTRIC RADIATION DETECTING MEANS DISPOSED ON THE OPPOSITE SIDE OF SAID PAPER SHEET FROM SAID LAMP TO RECEIVE THE ELECTROMAGNETIC RADIATION IN SAID SELECTED BAND WHICH PASSED THROUGH THE PAPER SHEET FOR PRODUCING A FLUCTUATING VOLTAGE RESPONSIVE TO THE MODULATION OF SAID SELECTED WAVE LENGHT BAND IN THE EMERGENT BEAM BY THE PAPER SHEET, AND MEANS CALIBRATED IN UNITS OF BASIS WEIGHT OF PAPER FOR INDICATING THE BASIS WEIGHT OF THE PAPER SHEET.