SU1550372A1 - Device for determining mass exchange characteristics of materials - Google Patents

Abstract

The invention relates to instrumentation technology and can be used in the study of mass transfer characteristics, in particular the moisture conductivity of building, refractory and thermal insulation porous materials. The aim of the invention is to increase the reliability of operation. In the device, which includes communicating vessels, an intermediate tank and a burette containing a cylindrical measuring part, neck and spout, the latter is made with an L-shaped cut, the top of which is adjacent to the neck of the burette, and on the side opposite to the L-shaped cut, A hydrophilic material is placed with a gap, with its upper part located above the neck, and the lower part below the level of the burette spout. 2 Il.

Description

The invention relates to an instrumentation technique and may find application in the study of mass-exchange characteristics, in particular, the water conductivity of building, refractory and thermally insulating porous materials.

The aim of the invention is to improve the reliability of the device.

In Fig.1 schematically shows the proposed device, a General view; figure 2 - burette.

A device for determining the mass exchange characteristics of porous materials includes communicating vessels 1 and 2, intermediate tank 3 connected by openings 4 and 5, respectively, with communicating vessels 1 and 2, B communicating vessels 1 and 2 are in contact with the surface of the liquid, respectively, sample 6 the material under investigation and a burette 7, containing a cylindrical measuring part 8, a neck and a nozzle 9, made with a D-shaped notch 10, the top of which is adjacent to the neck of the burette, and in the nose of the burette on the side opposite to th L-shaped cutout is arranged with a gap, providing a non-retarded penetration of liquid, the hydrophilic material 11, the upper part of which is located

above the neck, and the lower part is below the level of the nozzle of the burette.

The proposed device works as follows

In communicating vessels 1 and 2, the liquid is poured below the expected level of contact between the liquid and the sample and the measuring burette by 1-2 mm. Sample 6 is placed in vessel 1 so that the lower end of the sample does not touch the surface of the water, and seal the joint of the sample with the sides of the frame 1f, for example, using clay. Liquid is placed into the intermediate tank 3 below the level of the holes 4 and 5 and closed by a bead 12 with an opening. The gauge burette with a sealed upper end is filled with a rubber pear and the porous hydrophilic material, for example a wick, is fixed in the burette nozzle in the form of a half cylinder on the side opposite to the L-shaped cutout with a stainless steel clip. , with a gap that ensures unobstructed penetration of fluid,

Before installing the burette in connecting vessel 2, a so-called level of adjustment of the nozzle of the measuring burette is determined. To do this, use a glass of water and a prepared measuring burette. The latter, in an upright position, is immersed in a glass of water with the spout, diving the spout until the water supply from the burette is cut off. They fix the level of deepening of the nozzle of the burette at 2-3 mm below the top of the arch.

A gradual processing is installed in the vessel 2, having bury the nozzle of the burette in the liquid to the previously fixed level of regulation of the burette. There is no supply of liquid from the burette. Smoothly, gradually lift the burette, add the required amount of liquid to the communicating vessels until the sample contacts.

WITH SURFACE OF LIQUID IN SASUD 1.

This position of the burette is fixed and read on the burette scale, which is the initial count during the tests. The moisture loss in the buret is measured temporarily.

In the course of the experiments, if necessary, replenish the liquid in the burette, it is removed, again filled with liquid with a rubber pear, the initial reading is recorded, which is taken into account in the total flow rate during the experiment, and the burette is installed in the vessel 2 °

The tests are carried out before the onset of steady state moisture conductivity, when the fluid flow rate is constant, and the diffusion coefficients of moisture and moisture conductivity of the test material are determined from known ratios.

The cut-out in the form of an arch in the nose of the burette disrupts the forces of surface tension of the liquid, and the location of the top of the arch at the neck of the burette promotes air penetration directly into a wide part of the burette, mine resistance of the nose of the burette.

The presence of a wetted hydrophilic material in the buret nozzle connects the liquid in the burette and vessel and promotes air penetration into the burette with a reduced liquid level, ensuring reliable operation of the device, t0k, while lowering the liquid level, part of the wetted and hydrophilic material is exposed, rubbing some of the moisture, and absorbs moisture from the burette, thereby helping to overcome the forces of surface tension of the liquid and the penetration of air into the burette.

Making an arch cut in the spout of the burette allows disrupting - the surface tension forces with decreasing fluid level, increases the air flow into the burette and, accordingly, the fluid flow from the burette, which ensures fluid supply to the vessel in a wide range of flow rates.

Claims (1)

Invention Formula A device for determining the mass-exchange characteristics of porous materials, including communicating vessels and attached to one of the vessels is a burette with a cylindrical measuring part, throat and spout, characterized in that, in order to improve reliability, the burette spout is made with an L-shaped notch, the top which is adjacent to the neck of the burette, and in the nose of the burette on the side opposite to the L-shaped notch, the size is 515503726 with a gap, the hydrophilic material is above the neck, and the lower part the upper part of which is located the same level of the burette tip. - bottom neck, and bottom h the same level of the burette tip. figure 1 6 5 ft J 2 /. ABOUT Fig2