Enso-gutzeit Oy

Enso-gutzeit Osakeytio

Heikki Venalainen

Rauno Rantanen

Rertti Puumalainen

The invention concerns a procedure for measuring the coating quantities contained in coating layers deposited on both sides of paper, cardboard or equivalent material in the case in which both coating layers contain the same component emitting characteristic radiation. In the case most commonly encountered, both coating layers consist of the same coating material. In the procedure two functionally mutually independent radiation source/detector pairs are used, between which the coated paper or equivalent is placed. Separately each radiation source/detector pair effects excitation of fluorescent radiation in both coating layers under measurement and the total intensity of the excited radiation present at the detector is measured. If the base weight of the paper or equivalent is known, the coating rates are calculable from the results of measurement obtained. The base weight is most advantageously measured before the coating step with the aid of a separate source of radiation and a transmission detector.

Procedure for determining coating rates

The invention concerns a procedure for measurement of the material quantities in coating layers applied upon a base material, by utilizing x-ray radiation. The procedure is particularly suited for use in a paper or cardboard manufacturing process wherein onto a material web in continuous motion are applied by steps one or several coating courses. The radiation source and detector are both placed on one side of the moving web, and the procedure is based on measurement of the fluorescence radiation excited by the primary x-ray radiation obtained from the radiation source in the material underlying the coating layer that is to be measured. The primary and secondary radiation both are thereby compelled to pass through the coating layer under measurement before the arrival of the fluorescence radiation at the detector. The moving web may be equipped with a plurality of consecutive pairs of radiation source and detector, the first pair measuring the fluorescence radiation from the base material before application of the coating layer and the latter measuring the equivalent fluorescence radiation after applying the coating layer, in above-presented manner. It is alternatively possible to use one single radiation source and detector and to measure simultaneously the fluorescence radiation produced both in the coating layer under measurement and in the underlying base material.

Growing community of inventors

Imatra, Finland

Heikki Venalainen