SU1543301A1 - Method of granulometric analysis of fine-dispersed dielectric materials - Google Patents

Abstract

The invention can be used to obtain the distribution curve of particles of uncaptured fine-grained coke by size class and measure the average particle size in electrode manufacturing. The purpose of the invention is to reduce the analysis time. Between two contact surfaces, one of which is electrically conductive and made of an elastic material with a tensor-resistive effect, has a monolayer of monitored material. The surfaces are compressed with a certain force, the electrical resistance is measured between separate adjacent parts of the elastic surface, the histogram of the distribution of the measured electrical resistances is determined, and the particle size distribution is judged. The average particle size is determined by the average value of the measured electrical resistances. 3 il.

Description

The invention relates to the study of the physical properties of substances, and specifically to methods for the particle size analysis of dielectric fine materials, and can be used to obtain a distribution curve for particles of untreated fine grinding coal particles by size (size) and measure the average diameter of these particles in the electrode production, as well as in the coal, energy, chemical, mining industries.

The purpose of the invention is to reduce the analysis time. -I

FIG. 1 shows a picture of the flow of currents through the gaps of the elastic contact surface; in fig. 2 is a device for determining the distribution of particles of finely ground non-calcined coke (with a diameter of less than 0.11 mm), which implements the proposed method; on Lig.Z is the histogram of the electrical resistances of the controlled areas of the elastic substrate, which is also the histogram of the distribution of particles of the material being monitored by size (solid line — in this case, abscissa dc.), calculated by microscopic size of particle size intervals (dashed line).

%

WITH

with

An example of the current flow through the gaps 1 of the elastic contact surface 2 deformed by particles 3 of the material being monitored and located between the parts of this surface 2 in contact with the current-carrying contacts 4, which are connected to the measuring device, is shown in FIG. one.

The particles 3 of the controlled material are located on an inelastic bearing contact surface 5 made of a dielectric material. The painting shown in FIG. 1 illustrates the principle of operation of the device for implementing the method depicted in FIG. 2 and consisting of a sensor 6, having a fifth number of contacts 4 (slots) (in this case) connected by means of conductors 7 to a connector 8, elastic conductive surface 2 (electrically conductive rubber), contact dielectric surface 5, base 9, pressure member 10 and measuring circuit 11 connected to the inputs 12 of connector 8, and output to a computing device 13 recording can be connected and an indicating device (such as an oscilloscope or display).

The method is carried out as follows.

The monitored finely ground dielectric material is monolayer placed on the support contact surface 5 in one of the known ways (for example, embedded). Next, using a clamping element 10 with a certain force (depending on the thickness and elastic modulus of the elastic contact surface and selected experimentally), the contact surfaces 2 and 5 are compressed (the elastic surface is deformed) and measured by the measuring circuit 11 elastic electrically conductive surface 2.

Since the elastic contact surface 2 is made of a material with a tensor-resistive effect, the specific (volume) electrical resistance of the deformed gaps 1 depends on the degree of deformation, which in turn determines

5 0 5 0

0 5

0

five

is made by a particle size of 3 that causes deformation.

Consider, for example, the resistance between points a and b (Rat)

and „b (p-) -ab, (1)

where f is the material resistivity before deformation; dj is the change in the material resistivity caused by the deformation;

ib is the length of the segment at which resistance is measured. From the expression for the coefficient of sensitivity of the fp

c & f

where c. - - relative change in resistivity;

with al

CJ-T- - relative change

material thickness (1 - material thickness before deformation;

L1 - change in material thickness caused by deformation), we find Јj

KRL1 4f - {or because (Fig. 1, d is the radius of the particle 3 that caused the deformation),

l "KЈ2g Lr -Ј-Substituting the expression for others and (1):

2 K (1 g

Denote p-ab Roafc, i.e. resistance between points a and b (between adjacent contacts 4) in the case, if this section is not deformed, we obtain

01 /

R "b KoabO- f D) (2)

those. (r).

The signals from the output of the measuring circuit 11 are fed to a computing device 13, which determines the histogram of the particle distribution. controlled material size and average particle size, performed the following operations:

calculates the number of signals corresponding to the measured resistances, the values of which fall at specified intervals (from K, to R 4, from Kg

TO R

R ,, ..., from To IIJ;

K. to R-,

u 1 m

calculates the total number of signals corresponding to the measured resistances, the values of which fall in the interval from k, to Kp ,;

Finds the ratios of each number of signals corresponding to the measured resistances, the values of which fall within one of the specified intervals, to the total number of signals corresponding to the measured resistances, the values of which fall within the interval from R. to Um, i.e. determines the relative group frequencies of the histograms of the distribution of the measured resistances, which are also the relative group frequencies of the histogram of the distribution of particle size;

using equation (2), in which the values of R, l, and K are given, calculate the limits of the interpals of the distribution of particle sizes HKoc, b-U,)

Ms.; 7b

15433016

calculates the average of the measured resistances;

Obtaining an average value of the measured resistances of 1 sr, using vy- (3), calculates the average size

part of it

HuoaV) -ucp)

ten

CP 2KU

ABOUT

15

20

25

(3)

Claims (1)

Invention Formula The method of granuometric analysis of finely ground dielectric materials, which consists in the fact that the particles are placed monolayer between two contact surfaces, one of which is elastic, and squeezing; -, surfaces with a given force are applied, that is, , then, in order to reduce the analysis time, the electrical resistance between adjacent sections of the elastic contact surface is measured, the histogram of the distribution of electrical resistance between adjacent sections of the elastic contact surface is determined spine and judged from the histogram curve of particle size distribution, wherein the elastic contact surface made of electrically conductive material having heat zorezistivnym effect and inelastic contact surface is made of a dielectric material. remembers, gives to the registering and indicating device a histogram of the distribution of particles of the material under control, whose relative group frequencies are equal to the relative group frequencies of the distribution of histograms of the measured resistances, and the boundaries of the intervals are calculated by the formula (3); resistances 1 sr, using vy- (3), calculates the average size part of it HuoaV) -ucp) ten CP 2KU ABOUT Invention Formula The method of granuometric analysis of finely ground dielectric materials, which consists in the fact that the particles are placed monolayer between two contact surfaces, one of which is elastic, and squeeze; , then, in order to reduce the analysis time, the electrical resistance between adjacent sections of the elastic contact surface is measured, the histogram of the distribution of electrical resistance between adjacent sections of the elastic contact surface is determined spine and judged from the histogram curve of particle size distribution, wherein the elastic contact surface made of electrically conductive material having heat zorezistivnym effect and inelastic contact surface is made of a dielectric material. To measuring circuit J I | o.is I. On the recording and indicating device Phia.2 -i L, sSIS 10 15 C 2S JLjnjL ISV / 7 O.SS No. 5 FIE Editor M.Nedoluzhenko dcp.MM Compiled by M.Rogachev Tehred M.Hodanich Proofreader V.Girn to