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Electrical process and apparatus for determining or following changes occurring in a test body while an external influence acts upon it for determining the properties or nature of the body or of the influence
Electrical process and apparatus for determining or following changes occurring in a test body while an external influence acts upon it for determining the properties or nature of the body or of the influence
486,856. Measuring capacities. O'DELL, A. E. (Haardt & Co. Akt.-Ges.) Dec. 7, 1936, No. 33533. [Class 37] A process for observing changes occurring in a material while an external influence acts upon it, whether for determining the properties &c. of the material or of the influence, by measuring the dielectric constant of a substance forming the dielectric of a condenser, is characterized by the material to be tested being placed in stationary thin flat form in contact with an electrode of the condenser and being covered by an apertured plate through which the external influence gains access to it. The material to be observed may be films, foil, fabric or other sheets and in one form which is suitable for testing wood for drying and impregnation, a thin sheet of wood is clamped between two metal plates, one of which is apertured. The dielectric constant of the wood is measured during a period of time and from the variations in its value the progress of the treatment can be determined. In a modification, the permeability of a foil S to fluid is determined by mounting the foil between apertured plates H, P1, the lower of which with the plate P2 constitutes a condenser having a dielectric O, also formed of thin foil, whose dielectric constant varies with the fluid it absorbs. The spacing between the condenser plates may be determined by insulating pieces J. In a further form for measuring absorption of gases, the condenser is mounted in a pipeline and comprises a pair of apertured plates between which is clamped a foil adapted to take up gaseous ingredients. The influences acting on the test material may be temperature, pressure or the surrounding gas or liquid and the test material may be a film supported on a thin flat insulating carrier. Examples of such materials are given. Specification 276,468, [Class 37], is referred to.
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