SU1383168A1 - Optical method of checking strength of sheet fibre transparent materials and process of making same - Google Patents

Abstract

The invention solves the problem of continuous control of the anisotropy of the strength of a sheet of fibrous material during the technological process of its production. The goal is to reduce the time control. The material under study is illuminated with a parallel beam normally to its surface and simultaneously measure two luminous fluxes F and F ,,, scattered in the opposite direction in mutually perpendicular planes, and the entire luminous flux passing through the material (). The degree of strength of a mat.rial is judged by the coefficient va 1- (Fn / F |) V, where Y is the experimental function of the flux Φ (, p. The flux F is measured in the plane passing through the direction of the material in the process of its manufacture. At the same time, the entire luminous flux passing through the material under study and carrying information about the material thickness is measured. In the formula for evaluating the strength, a factor V is inserted which is an experimental function of the luminous flux. 2 ill. 5S

Description

The invention relates to methods for measuring the anisotropic properties of sheet light-transmitting fibrous materials and can be used in solving problems associated with non-destructive current quality control of these materials during their production.

The aim of the invention is to reduce the time needed to control the strength of sheet materials during the process of their production. A: FIG. 1 is a block diagram of the device illustrating the method; 2, an installation for verifying the operability of the method.

A parallel light beam falls on the test sample is normal to its surface. The light scattered by the sample in the opposite direction is received by two identical photodetectors located in mutually perpendicular planes at the same angle with, to the direction of incidence of the light beam. One of the receivers is in the plane coinciding with the direction of the material under study during the technological process of its production (with the speed vector of the V). The third receiver receives the entire luminous flux transmitted through the material under study F.

The device contains a source of 1,

disk 2 with pr; ores, engine 3, lens with diaphragm 4, holder 5 photomultiplier 6, photomultiplier power supply unit 7, voltmeter 8, photodiode and second digital voltmeter 10 ..

The light from source 1 (Fig. 2) is modulated by a disk 2 with slits, driven by a motor 3, and through a lens with a diaphragm 4 a parallel beam normally falls on the surface of the sample.

This capacitor paper is fixed in the holder 5 between two plane-parallel glasses. The backscattered light is received by a photomultiplier tube (PMT) 6 located at an angle to the optical axis of the installation, which can be installed in any plane passing through the optical axis of the installation by rotating around it by an arbitrary angle Lf relative to the Z axis. the power of the PMT is denoted by hygfy 7. A variable signal with

The PMT is recorded with a digital voltmeter 8. A photodetector 9 (a FKD-8 photodiode) has a receiving area of the order Z Z cm and is mounted directly behind the sample. The area of the light spot on the sample does not exceed 0.5 cm, therefore, within the error of the measuring devices used, it can be assumed that the entire light flux passed through the material is recorded by the photodetector 9, the variable signal from which is measured by the digital voltmeter 10.

On the installation, the signals U ,, are measured, proportional to the light F. and I „„, depending

UiH and, p, flows I

and 1 pr

on the thickness of the paper sample, which varies by overlaying layers of paper with exact matching of the machine direction in each layer. 6, and & measured according to the standard method on a tensile testing machine RMB-30-3. The values of the coefficient f are calculated by the formula

Y

s

f.

6 ..

 U and.

Using the corresponding values of U "p simultaneously measured at the installation, the dependence () was constructed, which is then used to optically determine the strength anisotropy coefficient of paper samples of the same type, but of different thickness, taken from other papermaking machines. Within 5% of the error, good agreement with the results of direct mechanical measurements was obtained. .

Thus, by comparison with the known, the proposed method allows continuous control of the anisotropy of the strength of sheet, fibrous light-transmitting materials, such as capacitor paper, during the process of their production.

Claims (1)

Invention Formula The optical method of controlling the strength of sheet fibrous light-transmitting materials in the process of their production, which consists in the fact that the material under study is illuminated by a parallel beam normally to its surface and the luminous flux scattered by the material in the opposite direction is measured. direction in two equal solid angles, oriented in mutually perpendicular planes at equal angles to the incident beam, characterized in that, in order to reduce the control time of the sheet material, the light flux passing through the material is additionally measured using a photodetector installed in the immediate vicinity of the material under study, one of the light fluxes scattered by the material in the opposite direction is measured in the plane passing through the direction of material flow, and the degree of anisotropy of the strength of the material is judged by the coefficient I n 1 - v 1- where „is the scattered light flux, measured in the plane passing through the direction of the material being drawn during its manufacture; one Light flux scattered in a plane perpendicular to this direction; the experimental function of the flux rate, which once for a given grade of material under study is found from the measured values (b),, (e) | (Fr) ,. (F,) g. (% p) i. for each of several samples that differ only in thickness, and the corresponding values of y are calculated by the formula m (gi) r (F.), / (u i%) (Oh,), - rupture voltage i the specimen, when the breaking force is applied along the direction of the draw; "S,) is the stress of the discharge of the same sample at the application of force perpendicular to the direction of drawing. Fotoprtimil fpus-j