SU1368720A1 - Gas-dynamic method of determining porosity of materials - Google Patents

Abstract

The invention relates to a measurement technique and can be applied to measure the porosity of materials in the mining, chemical, construction and other industries. The aim of the invention is to increase accuracy by melting the boundaries of the measured pressures. To determine the porosity of the sample, it is placed in the measuring capacitance of the device consisting of a measuring valve and a container of pressure valves connected by pipeline to a pneumatic valve. The measuring container is sealed. The device is then placed in a thermostat and the temperature in the thermostat is gradually adjusted to an optimum temperature with. which, as a result of the transfer of gas from the reference tank to the measuring tank, maximum pressure drops in the measuring and reference tanks will be observed. The opening time of the solenoid valve when measuring the porosity of materials by this method does not affect the final value of the optimum temperature. (L

Description

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The invention relates to a measurement technique and can be used to measure the porosity of materials in mining, chemical, construction and a number of other industries, as well as in laboratory practice.

The aim of the invention is to increase the accuracy by expanding the limits of the measured pressures.

The method is carried out as follows.

The porosity of materials pressed from ceramic powder was determined. At the same time, the sample was placed in a measuring device with the capacity of a known device for determining porosity, consisting of pipes connected to a pneumatic valve and reference (under pressure) containers. The measuring vessel was sealed. The device was then placed in a thermostat, and by smoothly adjusting the temperature in the thermostat, it was brought to the optimum, at which as a result of the transfer of gas from the reference tank to the measuring chamber, the maximum difference in the measuring and reference tanks was observed. After that, the valve was temporarily opened and a part of the gas was bypassed from the reference tank to the measuring tank; pressure differences in the tanks were measured by the formula

P . v, || i,

where is the pore volume;

VP is the total volume of the sample; V is the volume of the measuring capacitance; Vq is the volume of the reference capacity; And J is the change in pressure in the reference tank;

LR is the change in pressure in the measuring vessel, and the volume of the material was determined.

368720 .2

The opening time of an electropneumatic valve when measuring the porosity of materials by this method does not always differ by the maximum value of the variation of the response time. For example, with a time setting of 2.5 s, the spread of the time of operation can be not only +0.1 s, nor ± 0.01 s or 10 ± 0.00 1 s, However, this will not affect the final optimum temperature value.

Thus, the upper and lower boundaries of the bypass time of a significant influence on the value of T are not indicated.

Formula inventions

The gas-dynamic method for determining the porosity of materials, including by-passing gas from a reference tank to a measuring tank, measuring pressures in these tanks before and after a bypass, and measuring the volume of the solid form of materials, so that, in order to increase the accuracy by Before the bypass, the reference and measuring pressures, together with the body placed in it, are placed in a thermostat and the temperature in the thermostat is continuously regulated to a certain T from the equation

(

v "

)

K & V-1

-).

 .eK (

“,

-volume reference capacity;

- adiabatic coefficient; - gas constant;

EJ - effective channel bypass area;

ij - upper and lower boundaries of the bypass time;

g - free fall acceleration,

Claims (2)

Form ul of the invention consisting of measuring and reference (under pressure) tanks connected by means of a pipe with a pneumatic valve, the measuring tank was sealed. Then, the device was placed in a thermostat and the temperature was gradually adjusted in the thermostat to the optimal one, at which, as a result of gas bypass from the reference tank to the measuring one, the maximum differences in the measuring and reference tanks were observed. After that, the valve was opened for a while and bypassed part of the gas from the reference tank to the measuring one. J the pressure drops in the tanks were measured according to the formula v ₀ -v + V 4P ₂ δρ “ 2 ° A gas-dynamic method for determining the porosity of materials, including transferring gas from a reference container to a measuring one, measuring pressures in these containers before and after restarting, and measuring the volume of the solid form of materials, characterized in that, in order to increase accuracy by expanding the boundaries of the measured pressures, Bypass 30, the reference and measuring tanks, together with the body placed in it, are placed in a thermostat, and the temperature in the thermostat is adjusted by smooth regulation to a certain T from the equation - Building T = At "______________ km k-1 where P is the pore volume; V _c is the total volume of the sample; V is the volume of the measuring capacitance; ν ₀ is the volume of the reference capacitance; D Рсх, - pressure change in the reference capacitance; ΪΡ is the pressure change in the measuring capacitance, and the volume of the material was determined. 40 where ν _α is the volume of the reference capacitance; K is the adiabatic coefficient; R is the gas constant; f ₃ effective channel bypass area; 45 ΐ - ** - upper and lower boundaries of the bypass time; g is the acceleration of gravity. -