CS243687B1 - Probe lc measuring rlhkoeti loose materials - Google Patents

Abstract

Probe to measure the moisture content of bulk materials on the principle of sorption of the isotherm of the measured material, consisting of an absolute humidity sensor, such as lithium chloride, placed in a protective, water vapor barrier. A temperature sensor is located outside the protective basket space The probe can be used in particular to measure the humidity of organic products and materials such as grains, flour and the like.

Description

(54) Probe lc measuring rlhkoeti bulk materials

Probe for measuring the moisture content of bulk materials based on the isotherm sorption principle of the measured material, consisting of an absolute humidity sensor, for example lithium chloride, which is placed in a protective, vapor-permeable basket. A temperature sensor is located outside the protective chamber

The probe can be used in particular to measure the humidity of organic products and materials such as grains, flour, etc.

The invention relates to a probe arrangement for measuring the moisture content of bulk materials based on the sorption isotherm of the measured material.

Various principles are used to measure the moisture content of bulk materials, most often using the dependence of electrical conductivity or capacity on the moisture of the measured material.

Disadvantages of the conductivity method result from considerable dependence on the degree of compression and not the amount of impurities affecting the conductivity, the capacitance method is burdened by an error proportional to the variation of bulk density of the measured material.

Another method for measuring the moisture content of bulk materials is based on the existence of a sorption isotherm, i.e. the equilibrium of water in the material and in the vapor above the material at a given temperature. Probes of this type are equipped with a relative humidity sensor and have been studied only in the laboratory, they were probably not introduced into operational practice due to difficult selection of a reliable relative humidity sensor, due to the actual dependence of the sensor response to temperature, which makes evaluation difficult. relative humidity for ionic dust pollution.

The above-mentioned drawbacks are eliminated by the arrangement of the moisture measuring probe of the bulk materials according to the invention, based on the principle of sorption isotherm, which is based on the fact that inside an enclosed protective basket, which is water-penetrating, not for the measured material. for example, lithium chloride, which is connected to a protective basket by a base to which a probe hinge, usually hollow, is used to receive the lead wires.

A temperature sensor, preferably a platinum thermometer or a semiconductor diode, is located outside the protective basket space, for example in the hollow probe hinge.

The advantage of the probe according to the invention is the independence of the indication on the degree of compression of the measured material, and independence on the bulk density. Another advantage is the independence of sodium absolute humidity from temperature and considerable insensitivity to contamination.

An example of a specific embodiment is schematically shown in the accompanying drawing.

An absolute humidity sensor, for example lithium chloride, is connected to the protective basket 6 by a base χ within a porous closed protective basket 5 formed by a perforated cylinder with a bottom covered with a dense screen.

The probe hinge 6, which consists of a tube, which serves both for the electrical supply lines and a temperature sensor 6 consisting of a semiconductor diode, is connected to it for a longer time. Since the sensor X, for example lithium chloride, is a heat source, the protective basket 6 must be so large that the heating of the material outside the protective basket 6 is negligible.

Electrical data on absolute humidity and temperature shall be converted into moisture data of the material by means of a suitable transmitter or by means of tables, graphs or nomograms.

The probe according to the invention can be used to measure the moisture content of bulk materials in which the sorption isotherm has a sufficient steepness in the measurement area. The probe can be used, in particular, to measure the humidity of organic products and materials, such as grains, flour. Sondp is particularly suitable for measuring humidity during storage.

Claims (1)

SUBJECT OF THE INVENTION Probe for measuring the moisture content of bulk materials, based on the principle of the sorption isotherm of the measured material, characterized in that an absolute air humidity sensor (t), for example lithium chloride, which is connected to the defensive basket (2) by a base (3) to which the probe hinge (4) is further attached, wherein the temperature sensor (5), for example a platinum thermometer or a semiconductor diode, is located outside the protective basket (2), for example in the hollow probe hinge.