Commissariat a L'energie Atomique

Louis Destannes

Gilles Delapierre

Bernard Chambaz

Robert Meyer

Jacques Duchene

A strain gauge for compensating the creep of a support and a process for obtaining a strain gauge. The gauge is bonded to a support and includes a piezoresistive pattern etched on one face of a flexible film. A layer of a material subject to relaxation is deposited on the other face of the film. The relaxation layer is bonded to a test piece of the same material as the support. A constant force is applied for producing a creep on the test piece and the resistance of gauge as a function of time is measured. The thickness of the relaxation layer is adjusted to cancel out the evolution of the resistance of the gauge.

Regulatable creep strain gauges and process for obtaining such gauges

The present invention relates to a capacitive hygrometer comprising a capacitor (1) having a dielectric material (3), whose dielectric constant varies as a function of the quantity of water absorbed. It has on one of its conductive faces numerous fissures bringing the dielectric material into direct contact with the atmosphere whose degree of humidity is to be measured. However, the electrical continuity of the fissured conductive face is maintained. Application to the measurement of the degree of humidity of the air.

Capacitive hygrometer and its production process

Capacitive hygrometer

The method consists in forming a first insulating plate coated with an electrode, in depositing at the periphery of the plate a wall formed of a first material which is chemically inert with respect to the film and fusible at a first temperature, in passing through the wall a filler tube of a second material having a higher melting point than the wall, in forming a second transparent insulating plate coated with a semitransparent electrode, in sealing the tube in the wall and the first and second plates on the wall by heating the cell elements to a temperature at least equal to the first temperature and lower than the melting point of the second material, then in allowing the cell elements to cool.

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Eybens, France

Louis Destannes