Abrégé

A Constant Volume Gas Thermometer (CVTG) device for measuring the temperature with high precision over a wide temperature range comprises a pressure measurement device (13), which comprises a mechanical assembly forming a membrane (4). The capillary tube (3) communicates with the bottom side (5) of the membrane (4) and a first pressure measurement element (2) on the membrane (4) generates a signal in dependence of a deformation of the membrane (4). Further, the CVTG comprises electronic means (18) for reading and correlating the signal of said first pressure measurement element (2) to the temperature of the gas cartridge (1). The gas volume inside the pressure measurement device (13) is minimized by careful design and tight tolerances. To measure pressures below 0.1 MPa inside the CVGT with sufficient accuracy, the CVGT include a pressure measurement device (9) which is based on the Pirani measurement principle. A Pirani measurement device measures the thermal conductivity of the surrounding gas. To this end, a thermally insulated wire or surface is heated electrically to a defined temperature, while the surrounding gas is at ambient temperature. If the thermal conductivity of the surrounding gas changes, either the Pirani element's temperature changes, or the electrical heating power needs to be adapted in order to maintain the Pirani element's temperature.

Classes IPC  ?

• G01K 5/34 - Mesure de la température basée sur la dilatation ou la contraction d'un matériau le matériau étant un fluide contenu dans un corps creux ayant des parties qui sont déformables ou déplaçables sous l'effet de la pression développée par le matériau le corps étant une capsule

Produits et services

Metal and wood working machines. Thermometers, in particular bimetallic thermometers, electric contact thermometers and thermometers of all kinds for scientific and industrial uses; electric instruments for measuring temperature and humidity; temperature and humidity regulating and controlling apparatus; electronic regulating and controlling apparatus as well as electric apparatus for measuring and regulating pressure, medical thermometers.