SU1062585A1 - Dispersed material heat conduction determination device - Google Patents

Abstract

DEVICE FOR DETERMINATION OF HEAT CONDUCTIVITY OF DISPERSED MATERIALS, with holding heater, rheostat. A temperature sensor and recorder, blocks of time, matching and measuring devices, characterized in that, in order to increase the reliability and accuracy of measuring the thermal conductivity of materials that change phase state with temperature, the heater and the temperature sensor in the contact are installed on the probe, In this case, the heater is connected to the rheostat and the time unit through the measuring instrument unit, and the temperature sensor is connected through the matching unit with the temperature recorder. 2. The device, according to claim 1, is based on the fact that the probe is made of an electrical insulating material (L rial, whose thermal conductivity is at least an order of magnitude less than the thermal conductivity of the material under study. 3. The device according to claim 1, characterized by that the heater is made of tape.

Description

The invention relates to a technique for determining thermal values, in particular, for determining the thermophysical parameters of diaphragm materials, such as mine and backfill materials, molding sands and frozen soils. A device is known for determining the thermal conductivity of dispersed media including soil, rock, mining, and backfill materials using the probe method, including a heating probe, measuring instruments, and a temperature sensor. Moreover, as a temperature sensor, it is applied to a thermocouple with an exit to a galvanometer, which records the temperature with the required accuracy and is able to work only in laboratory conditions 1. A heat source, a probe, is introduced into the test environment, which takes into account either the amount of heat feeding the probe, or taking into account changes in temperature in the environment around the probe or inside the material filling the probe. This device is applicable when it is impossible to break the structure of the material by taking a sample for analysis, but when a small change in the structure due to the introduction of the probe is permissible. The closest to the invention to the technical essence is a device for determining the thermal properties of rocks, based on the principle of a probe instantaneous heat source, including a heater, measuring instrument blocks, a rheostat, time and matching blocks, a sensor and a temperature recorder. In this device A thermocouple with a galvanometer is used in the temperature sensor. The heater and temperature sensor are located separately 2j. The drawbacks of the device are the impossibility of taking measurements in natural, in particular field conditions, additional measurement errors due to the instability of the contacts between the sensor, the heater and the object under study. In order to obtain noticeable temperature changes at a distance separating the temperature sensor from the heater, a certain power and heating time is required. The purpose of the invention is to increase the reliability and accuracy of measuring the thermal conductivity of materials under natural conditions. The goal is achieved by the fact that the device provides a definition (the thermal conductivity values of dispersed materials containing a heater, a rheostat, a sensor and a recorder / temperature, time blocks, matching and measuring devices, a heater and a temperature sensor in contact, are installed on the probe, at the same time, the heater is connected to the rheostat and the time unit through the measuring instrument unit, and the temperature sensor is connected through the matching unit with the temperature recorder. At the same time, the probe is made of electrically insulating material The core of which is at least an order of magnitude less than the thermal conductivity of the material under study. In addition, the heater is made of ribbon. Fig. 1 shows a block diagram of a device for determining the thermal conductivity of dispersed materials, and a probe in Fig. 2. The device consists of a series-connected rheostat 1, unit 2 measuring instruments measuring the power of the heater, probe 3, unit 4 of the matching, temperature controller, made in the form of a frequency meter 5. A time unit 6 is connected to the probe through the unit of measuring instruments 2. The probe 3 consists of a heater 7 and a temperature sensor 8 in the form of a temperature-sensitive quartz resonator located on a cylindrical rod 9 made of an electrically insulating material, for example, fluoroplastic, a protective coating 10 and a gland element 11. The protective coating can be an EP-730 compound ( GOST 20824-75). The rheostat 1 is connected to the heater 7 of the unit 2 and the block 6 of time through the block 2 of measuring instruments. The temperature sensor is connected in series with the matching unit 4 and the frequency meter 5. The device operates as follows. . The probe 3 is lowered into the measured medium. Using the temperature sensor 8 in the form of a quartz resonator and frequency meter 5, the medium temperature TQ is determined. Through a rheostat 1, block b of time, triggered with a delay of time to turn off, a heat impulse is reported to the heater 7 during the time Co. After a time, the temperature of the heater T (f) is measured. According to the measurement data, the excess temperature .. j .- .. 1 4; tl t, -to

de | —the amount of heat released by a unit of length of the linear heat source q, 0.24 Ult;

l

thermal conductivity of the object under study,

time from the beginning of heating to measuring the temperature of the heater;

heating time;

from where

 -li ..-,

The thermal conductivity of the cylindrical rod 9 is an order of magnitude lower than the thermal conductivity of the measured medium; therefore, the losses on the heating of the rod affect the measurement accuracy little and are not taken into account in the calculation.

Thus, the proposed device makes it possible to reliably and accurately determine the thermal conductivity of soil grounds, including frozen, which is especially difficult for rocks under conditions of their natural occurrence without disturbing the structure and phase state, increases reliability.

Claims (3)

DEVICE FOR DETERMINING THE THERMAL CONDUCTIVITY OF DISPERSED MATERIALS, containing a heater, a rheostat, a sensor and a temperature recorder, time blocks, matching devices and measuring devices, characterized in that, in order to increase the reliability and accuracy of measurements of thermal conductivity of materials that change the phase state when the temperature changes, the heater and the temperature sensor in contact are mounted on the probe, while the heater is connected to the rheostat and the time unit through a block of measuring devices, and the temperature sensor is connected through the matching unit with the temperature recorder. 2. The device, by π. 1, characterized in that the probe .g is made of an insulating material whose thermal conductivity is at least an order of magnitude lower than the thermal conductivity of the material under study. 3. The device according to π. 1, characterized in that the heater is made tape. About No. СП 00 СЛ