CS244783B1 - Electrode of capacitive hygrometer - Google Patents

Abstract

The solution concerns the electrode of a capacitive hygrometer. , The electrode consists of a core made of a flexible electrically non-conductive material /2/, on the functional side of which there is at least one malleable conductive electrode /1/. On the other side, the core is mounted on a solid, electrically non-conductive base /3/. The relative permittivity of the flexible non-conductive material /2/ and the solid non-conductive base /3/ is less than or equal to the relative permittivity of the dry measured environment. The electrode modified in this way is used mainly in measuring humidity on the surface of building structures and components, both in laboratories and in situ.

Description

The invention relates to a capacitive hygrometer electrode for detecting the moisture of porous building materials, even uneven.

Water _f resp. the humidity of the porous building materials may have an influence on the value of their relative permittivity and therefore can be determined by measuring the change in relative permittivity or the loss angle of a specific capacitor whose dielectric is a wet building material. The capacitive hygrometer, which has been used to detect the moisture of porous building materials, works on this principle. The capacitor hygrometer capacitor electrodes are geometrically arranged according to need, with the condition that the capacitive hygrometer functions properly in order to ensure perfect contact of its electrode across the surface with the surface of the measured object. Even a small air gap between the electrode and the surface of the measured object distorts the final result, which is a disadvantage of these hygrometers. For this reason, the surface of the object to be measured must be suitably machined, eg ground. This adjustment is especially necessary when measuring moisture on building structures.

This drawback is overcome by the capacitive hygrometer electrode of the invention. Its essence is that it consists of a core formed of a resilient, non-conductive material, which may be, for example, foam or moss rubber. On the functional side, the resilient non-conductive material is provided with at least one formable conductive electrode and on the other hand it is fixed on a solid electrically non-conductive base, for example polystyrene. The relative permittivity of the flexible non-conductive material and the solid non-conductive base is less than or equal to the relative permittivity of the dry measurement environment.

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The capacitive hygrometer electrode thus arranged has perfect mechanical contact over the whole surface with the surface of the measured material, even in case of surface irregularities, if these are not too large and therefore the measurement results do not show distortion.

The formation of the capacitive hygrometer electrode is schematically shown in the accompanying drawing, in which Fig. 1 is a sectional view of the electrode and Fig. 2 is a bottom view of the electrode.

The electrode consists of a core of a flexible, non-conductive electrode 2, easily deformable, in this case a foam. On the functional side of this electrically non-conductive material 2, i.e. on the side which is to be applied to the object to be measured, there are two ductile conductive electrodes 1, made, for example, of a metal fabric. On the other hand, the core of the resilient non-conductive material 2 is adhered to a solid, but not electrically non-conductive, base 2 here on polystyrene. The relative permittivity of the flexible non-conductive material 2 and the solid non-conductive base 2 must be low, less than or equal to the relative permittivity of the dry measurement environment.

By pressing the treated electrode onto an uneven surface, the electrode copies the surface with its unevenness, unless the unevenness is too great. In this case, the capacitance of the specific capacitor changes only slightly.

The electrodes treated in this way are used especially in the measurement of moisture on the surface of building structures and components, both in laboratories and in situ.

Claims (1)

Capacitive hygrometer electrode, characterized in that it consists of a core formed of a resilient electrically non-conductive material (2), for example a foam or moss rubber, provided with at least one ductile conductive electrode (1) on the functional side and 3), for example polystyrene, wherein the relative permittivity of the resilient electrically nonconductive material (2) and the solid electrically nonconductive base (3) is less than or equal to the relative permittivity of the dry measurement environment.