SU970272A1 - Method of determination of electrofield substance electrostatic charge relaxation time - Google Patents

Description

(5) METHOD FOR DETERMINING THE TIME OF RELAXATION OF ELECTROSTATIC CHARGE OF AN ELECTRIZED SUBSTANCE

one

The invention relates to electrical measuring equipment and is intended for use in the study of the electrostatic characteristics of materials used in the chemical, oil and other industries.

The known method provides a measurement of the electrifiedness of a substance and an indirect estimate of the relaxation time of its electrostatic charge, involving the repeated electrification of the sample under investigation and the recording of charges followed by analytical processing of the obtained measurements 1.

The disadvantages of this method are determined by the limited scope of its application, the considerable complexity of implementation, and the large estimation errors.

The closest technical solution to the proposed method is

determining the relaxation time of the electrostatic charge of an electrified substance, which involves measuring the charge of the test substance at certain time intervals, constructing a discharge curve from the obtained points and estimating the desired relaxation time taking into account the curve found using well-known 2JI methods.

Claims (2)

In practical use of this method, there is no possibility of detecting several points of the discharge curve after the end of the process of electrization of a substance. The electrification process is characterized by instability, the data obtained for plotting the curve are approximate, and the flow conditions of the elect. The static charge of the test specimen is significantly different from those occurring in natural conditions. All this causes significant errors of the known method. The purpose of the invention is to increase the accuracy. the electrified substance is first loaded into the measuring cell, and then discharged in portions, fixing at the same time the value of the resulting electrification current The ki., The implementation of the proposed method is carried out as follows. The test substance is preliminarily electrified and loaded into the measuring cell, where an electrostatic charge on its walls causes electrification current. According to the value of the current, the charge acquired by a unit mass of the substance is calculated directly in the process of its electrification, which is the starting point of the variable curve. Then, at certain time intervals, free portions of the substance are discharged from the measuring cell. At each stage of discharge, the free charges lead to the formation of a current 3 :, characterizing the charge q of the substance at the moment of the i-th discharge unloading of the i-th portion of the substance beyond the measuring cell. As the electrostatic charge is scattered over time, the charge of the material being discharged becomes smaller. It calculates c by diagrams, for example, by the method of graphical integration. The values of the charge of a substance related to its mass (mass charge of a substance) obtained at certain time intervals determine the subsequent points of the discharge curve, which it finds from the desired relaxation time. The amount of pre-electrified substance entering the measuring cell should be sufficient to select several batches. The number of chunks is determined by the number of points of the discharge curve from which it is constructed. It is recommended to take portions until the electrification current is commensurate with the sensitivity threshold of the recording device (microampere During the whole experiment, the measuring cell is grounded through the recording device, which corresponds to the conditions of electrostatic charge flow in natural process devices, which are made of metal are also grounded. The relaxation time T characterizes, as is known, the rate at which the electrified substance returns the excited system to the equilibrium state: the shorter the relaxation time, the faster the electrostatic charge of the substance becomes equal to 0. During the time t, the charge of the substance decreases by a factor of 2.7 times. If you know the relaxation time, you can determine the time interval for which the initial electrostatic charge will be almost completely removed from the substance.This is used to ensure the electrostatic safety of technological processes and equipment, to enter planned process stops for a time sufficient to discharge the charge, or sent the substance in the ground small relaxation capacitances, where it has the ability to discharge in time. Formula of the Shadow Method A method for determining the relaxation time of an electrostatic charge of an electrified substance based on constructing a discharge curve by points characterizing the electrostatic charge of a substance in certain periods of time, characterized in that, in order to improve the accuracy, the substance is first loaded into the measuring cell, and then discharged in portions, while fixing the value of the cell's electrification current being formed. 5 "Sources of information taken into account during the examination 1. USSR author's certificate N576679, cl. H 05 F 1/00, 1973. 9702726 2. Egorov V.N. Electrostatic effect in friction of synthetic polymers on metal surfaces. - Plastics 19b5. s П с. 62-6.