SU667873A1 - Method of determining structural-critical moisture-content of ceramics - Google Patents

Description

The invention relates to the production of building materials and products and can be used in. technologies for the production of ceramics.

A known method for determining the structurally critical moisture content of ceramics by drying control samples 1.

However, this method has a low volume. definition.

A known method for determining the structural-critical moisture content by determining the moisture content of a sample during the drying process is based on the use of mass transfer potential sensors made from a reference body (filter paper) that are in thermodynamic equilibrium with a ceramic sample subjected to drying 2J.

However, this method is very laborious, the determination of the structural critical moisture content must be carried out on a series of samples in the amount of 8, 12 pcs. - within 5-11 days.

The purpose of the invention is to accelerate the generation and increase the accuracy of measurements.

The goal is achieved in that according to the proposed method, the sample is subjected to ultrasonic sounding during the drying process, continuously measuring the speed of ultrasound pulses through the sample, and the structural-critical moisture content of ceramics is judged by the humidity corresponding to the minimum speed of ultrasonic pulses.

One sample (product) of the material under study is interfered between the generator and the receiver of longitudinal ultrasonic waves, after which the sample (product) is dried according to a predetermined mode, while continuously changing the speed of passage of longitudinal ultrasonic pulses through the sample, and the moisture content of the material is continuously measured ( for example, using scales with remote control).

The drawing shows the change in the velocity of the longitudinal waves during the drying of ceramics, determined by the characteristic curve C f (t), on which two extremes are fixed.

The second extremum (minimum) on the curve C ((t) corresponds to the state of ceramics, in which capillary macroporosity and shrinkage deformations are completed in the material. Therefore, sounding and determining the drainage of the material is made until the second extremum (minimum) appears on the curve the velocity of the passage of longitudinal ultrasonic waves through the sample. The moisture content measured at the time of fixation of the specified extremum is iskomoft the value of the structural-critical

moisture content.

Using the proposed method of determinations I structurally critical moisture content reduces the duration of experimental studies and their scope: allows the determination of the desired parameter on a single sample, which increases the accuracy of determination;

allows to do without complex calculations and preliminary graphical dependencies;

makes it possible to determine the value

dtpyK TypHO-Critical moisture content is not average in production conditions, which is not possible with other methods;

allows you to assign and correct the technological modes of drying products from building ceramics. ,

Claims (2)

1. Lykov A.V. Theory of drying. M., Energy G 1967. 2. USSR author's certificate J5 № 467257, cl. G 01 N 19/10, 1973. in fff 12 lU- 16 18 th 22