RU141361U1 - INSTALLATION FOR DETERMINING NON-FROZEN WATER IN FROZEN SOILS AND POROUS MATERIALS - Google Patents

Abstract

A device for determining the content of unfrozen water in frozen soils and porous materials, containing a bottle with a sample and a resistance thermometer placed in the working chamber of the circulation unit, heat flow sensors placed on the side and end sides of the boxes, connected to the circulation unit through the cryostat inlet and outlet coolant pipelines and an electrically actuated control valve installed between the pipelines.

Description

The utility model relates to the field of cryology and geocryology, namely, the processes accompanying the freezing and thawing of moist soils, soils and porous building materials.

Known experimental setup developed by B.V. Grigoryev and A.B. Shabarov [Application No. 2012149324/15, “Installation for the determination of unfrozen water in frozen soils”, pos. decision dated 05/17/2013], which includes the test sample, temperature sensor, heat flow sensor, heat-insulating casing, cryostat.

The main disadvantages of these installations are:

Insufficient area of overlapping by the sensor of the heat flux of the heat exchange surface between the box with the sample and the surrounding space, and insufficient. the flexibility of the control elements of the installation in terms of selecting and changing the freezing / thawing mode according to the temperature change algorithm of interest.

The described design is used to determine unfrozen water in moist soils and soils; however, data on the content of unfrozen water in porous building materials are necessary in the construction industry.

The technical result of the proposed utility model consists in increasing the accuracy of the results obtained, expanding the scope of the installation for both soils and dispersed soils, and for porous building materials, and replenishing the list of various operating modes of the installation.

This is achieved by the fact that the area of overlapping by the heat flux sensors of the sample-environment contact surface is increased by placing, in addition to the sensor on the side of the boxes, two more sensors from the ends of the boxes;

in addition, a control valve with an electric actuator is introduced between the supply and outlet pipelines in the installation diagram, which allows, depending on the required freezing / thawing mode, to smoothly control the coolant supply to the circulation unit by draining part of the liquid from the supply pipe to the outlet, bypassing the circulation unit, this makes it possible to change the temperature in the circulation unit according to the specified algorithm. Also in this design, the possibility of freezing and thawing moist soils, soils and porous building materials is implemented.

The essence of the utility model is illustrated by drawings, which depict:

In FIG. 1 shows an experimental setup. It consists of: cryostat 1; PC 2; resistance thermometers (TSP) and heat flux sensors (DTP) 3 (in Fig. 1 the lead wires are displayed); circulation unit 4; pipelines 5; analog-to-digital converter (ADC) 6; electric control valve 7, electronic control device for electric drive 8.

In FIG. 2 shows a device of a sample box prepared for an experiment.

It includes: box with cover 1; test sample 2; resistance thermometer 3; heat flow sensors 4, 5.

An experimental setup with an external cooling circuit includes: a cryostat; circulation unit, which is connected to a cryostat for supply and removal of coolant. In the working chamber of the circulation unit there is a sample under study, heat flux sensors and platinum resistance thermometers, an analog-to-digital converter, which serves for processing and converting signals from a heat flux sensor and TSP and outputting data to a PC; thermally insulated pipelines for connecting the cryostat and the circulation unit into a single circuit; control valve.

Installation works as follows

The wet sample to be examined is placed in a box, a resistance thermometer is inserted in the center of the boxes, a lid is put on, then on the side surface of the boxes and on the top and bottom sides are fixed three heat flux sensors in the form of a plate and a disk, respectively, as shown in FIG. 2.

The bucks are placed in the working chamber of the circulation unit, the unit is closed with a lid and the terminals of the thermometer boxes and heat flux sensors are connected, as well as the thermometer located in the chamber to the ADC, they are left for 2-3 hours to achieve a zero heat flux density between the sample and the chamber air, and equal temperature of the sample and the surrounding space.

The circulation unit is connected to the fittings of the external cryostat cooling circuit via pipelines, and the cryostat evaporation chamber is filled with thermostatic liquid (antifreeze) in a volume of 7 liters, then the cryostat is turned on and the set temperature is set. After the temperature of the thermostatic fluid begins to decline, open the taps and turn on the pump to pump the fluid along the circuit.

Depending on the freezing mode, the necessary position of the control valve is set, or an algorithm for changing it over time, temperature, etc.

Information sources

1. Danielyan Yu.S. Studies of nonequilibrium heat and mass transfer in soils with phase transitions of moisture in relation to the design of the arrangement of oil fields. Dis. d.f. - MD, Tyumen. 1997.

2. Tsytovich N.A. Mechanics of frozen soils. M.: Higher School Publishing House, 1973. 448 p.

Claims (1)

Installation for determining the content of unfrozen water in frozen soils and porous materials, containing a bottle with a sample and a resistance thermometer placed in the working chamber of the circulation unit, heat flow sensors placed on the side and end sides of the boxes, connected to the circulation unit by means of a cryostat inlet and outlet coolant and an electrically actuated control valve installed between the pipelines.

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