SU972322A1 - Plant for determination of material water yeilding capacity - Google Patents

Description

(54) INSTALLATION FOR DETERMINATION OF MOISTURE / V ATEPIALOB

one

The invention relates to devices for determining the physical properties of substances, in particular for determining the moisture recovery of materials.

A device for measuring the mass of materials by dynamic weighing is known, consisting of analytically weights, one cup of which is replaced by a basket suspended on a thin wire, in which the sample is placed. The basket is located in the electric drying oven 1.

However, the use of this device in determining the moisture loss of materials in the process of their heating introduces a methodological error due to the negligible influence on the amount of change in the sample mass of the ambient temperature and pressure.

The determination of the moisture content of the material under study using a known device in various conditions, atmospheric pressure, ambient temperature) gives poorly comparable results. In this case, the methodological error is 15-200 / 0.

Closest to the proposed technical essence and the achieved result is an installation for determining the moisture yield of a material, including a chamber with the test material and a cover placed in a heated casing, a heating device and a measuring device 2.

The disadvantage of the known installation is that the amount of formed

The moisture Q is determined by the weight of the condensate that is formed, and the accuracy of the moisture content is therefore low.

In addition, it is used to determine the moisture content of fruits and vegetables, and high temperatures are not required for this type of material.

The purpose of the invention is to improve the accuracy of determining the moisture yield.

The goal is achieved by the fact that in the device, which includes a chamber with studied material and a lid, placed in a heated casing, a heating device and a measuring device, the lid is made in the form of a corrugated plate, on which the measuring device is fixed, the heating device is installed in the form of the studied material of the bath filled with a liquid coolant, in the walls of which the heating elements are placed, and the installation is equipped with a base with nano-ers, reinforced both on it and on the support rings with a casing fixed in them, installed with the possibility of reciprocating movement along guides relative to the bath placed on the base.

The drawing shows an installation for measuring the moisture performance of materials, the appearance.

The test sample 1 of the moistened material is placed in a thin-walled chamber 2, made of a high-tin-conductive oxide-resistant material (for example) MOO-grade copper). The top of the chamber 2 is covered with a lid 3, which is a corrugated membrane, whose surface is equipped with strain gauges 4 resistances interconnected and connected to the measuring electrical device. To prevent condensation of water vapor on the walls of the i-hermetic cage 2, the latter is installed in a heated casing 5, which is not made of refractory quartz ceramics. A heating element 6 is mounted into the casing wall. The leads (which are connected to the terminals of the autotransformer. The casing 5 is rigidly fixed in the support rings 7, through which the reciprocating movement of the casing coB.viecTHO with the gauge but 8 guides 8 .С) According to the bath 9, in the walls of which e.chemical nagas are placed |, there are evative elements) 10. Vain 9 is filled with liquid tag (; a container and is located under the chamber with the sample under study. The temperature of the liquid heat carrier is controlled by thermocouple 11 and constant throughout the experiment using electrical heating elements 10 are connected via the insulating pad 12 to the terminals of the autotransformer. Bath 9 mounted to the base 13. To maintain a constant liquid level in the bath wall nredusmotrepo drainer 14.

The installation works as follows.

The moistened sample 1 is placed in the chamber 2 and hermetically sealed with the lid 3. An autotransformer and heaters are connected to the network and mounted into the walls of the casing and bath. Control thermocouples register the temperature of the heat carrier and the inner wall of the casing. After the unit has reached the operating mode, the instrument is installed in the casing with the test sample, after which they are jointly moved along the guides to the lowest position defined by the stop 15.

When lowering the chamber with the next m wetted shaped in the bath with a heat-transfer fluid, intensive evaporation of moisture occurs. In the closed chamber volume, an overpressure is generated, the magnitude of which is directly proportional to the amount of water evaporated. Under the action of overpressure. The membrane of the lid 3 bends, while the strain gauges 4, by changing their characteristics, cause imbalance

the bridge. The error voltage is a function of the overpressure in the chamber and is recorded on the chick of the recording instrument. Thermocouple 16 registers the temperature of the vapor-gas mixture in the chamber. According to the magnitude of the excess davlenin and the temperature of the vapor – gas mixture in the chamber, referred to the corresponding time interval from the moment of the start of heating, using the expression

t

H

sample mass, kg; steam gas mixture.

T,

temperature of gas-vapor mixture; TO;

T, ambient temperature. TO; V is the volume of the hermetic chamber, R is the universal gas constant.

PTs-air mass in the hermetic chamber, kg; –molecular air weight,

kg / kmol

determine the value of b.1 material loss.

The proposed installation improves the accuracy of the determination by using a pressure meter as a measured pressure meter.

Claims (2)

1.Knigina G.I. and others. Laboratory work on the technology of building ceramics and artificial porous aggregates. M., Higher School, 1977, p. 145-146. 2. USSR author's certificate number 240327, cl. G 01 N 7/16, 1969.