Endress U. Hauser Gmbh U. Co.

Endress + Hauser Gmbh + Co. Kg

Endress+hauserse+co. Kg

Dieter Funken

Igor Getman

Sergej Lopatin

Peter Seefeld

Mike Touzin

Thomas Sulzer

Rainer Herrmann

Jurgen Kruger

Jurgen Tetard

A pressure transfer module for transfer of pressures less equals 100 mbar, and suitable for high temperature applications, comprising an isolating diaphragm outwardly sealing a first pressure chamber; a transfer diaphragm outwardly sealing a second pressure chamber; and a pressure transfer path connecting the first pressure chamber with the second pressure chamber. The first and the second pressure chambers and the pressure transfer path are filled with a pressure transfer liquid, via which a pressure acting externally on the isolating diaphragm is transmitted to the transfer diaphragm. The pressure transfer liquid is under a pre-pressure, especially a pre-pressure of greater than or equal to 30 mbar, especially greater than or equal to 50 mbar. The isolating diaphragm and the transfer diaphragm under the pre-pressure assume a starting position, from which they are deflected by the pressure to be transmitted, and the starting positions of isolating diaphragm and transfer diaphragm lie as a function of size of the pre-pressure and size of the pressure to be transmitted within deflection ranges of the diaphragms, in which deflections from their starting positions have due to their formation a non-axisymmetric part, especially an antisymmetric part.

Pressure transfer module and pressure measuring transducer having a pressure transfer module

A pressure transfer device comprises a pressure transfer device body and an isolating diaphragm, wherein, between the surface of the body of the pressure transmitting device and the isolating diaphragm, a pressure chamber is formed, whose volume is dependent on the position of the isolating diaphragm. The isolating diaphragm has a material thickness and a deflectable working region with an area A, wherein the isolating diaphragm has a reference position, in which the pressure chamber contains a reference volume V, and the isolating diaphragm is deflectable from the reference position at least so far in two directions, that the volume of the pressure chamber varies between values of up to V+/&#x2212;&#x394;V, wherein associated with a volume change &#x394;V is a dimensionless deflection measure w, with w(&#x394;V):=(3&#xb7;&#x394;V)/(A&#xb7;h), wherein &#x394;Vis dimensioned in such a way, that |w(&#x394;V)|&#x2267;2.5; wherein, in the case of all w(&#x394;V), for which |w(&#x394;V)|&#x2266;|w'(&#x394;V)|, wherein |w&#x2032;(&#x394;V)|&#x2267;0.5&#xb7;|w(&#x394;V)|, the isolating diaphragm has a non-axisymmetric deflection mode, which is superimposed on the axisymmetric deflection of w(&#x394;V), and wherein the deflection of the non-axisymmetric deflection mode, in the case of |w(&#x394;V)|=0.4&#xb7;|w(&#x394;V)|, amounts to at least 0.3 times the maximal deflection of the non-axisymmetric deflection mode.

Pressure transfer device and pressure measuring device with such pressure transfer means

Temperature measuring circuit

A dew-point sensor for a dew-point measuring device for measuring the water vapor dew point in gases comprises a sensor surface which is exposed to the gas to be measured and on which on cooling to the dew-point temperature water vapor condenses. Mounted on the sensor surface are two electrode structures which comprise electrode portions which are arranged a uniform interval parallel to each other and which are covered with a moisture-insensitive insulating layer. The reaching of the dew-point temperature is determined by measuring the impedance or capacitance between the two electrode structures. The distance between the electrode portions, arranged parallel to each other, of the two electrode structures is of the order of magnitude of the diameter of the largest condensation droplet forming on reaching the dew-point temperature, or smaller than said diameter, and the thickness of the insulating layer is small compared with the distance between the electrode portions.

Dew-point sensor

For measuring the water vapor dew point in gases, a moisture-dependent electrical quantity of a sensor surface suitable for indicating formation of dew droplets is held by temperature control at a desired value corresponding to a stable dew mass. The temperature of the sensor surface corresponding to the desired value of the moisture-dependent electrical quantity is measured as dew point temperature. For compensating the influence of soiling, from time to time the desired value of the moisture-dependent electrical quantity is set in that the temperature of the sensor surface is lowered from a value lying above the dew point temperature and a periodic time temperature variation superimposed on the lowering. If the sensor surface is soiled, periodic time variations of the moisture-dependent electrical quantity occur at the same time but they become a monotonic variation when the dew point temperature is reached. The value of the moisture-dependent electrical quantity measured on the transition of the periodic time variations to a monotonic variation is then used as the reference or desired value which is maintained by the control of the temperature of the sensor surface. Furthermore, the control parameters for controlling the moisture-dependent electrical quantity are continuously corrected on the basis of an oscillation analysis.

Arrangement for measuring the water vapor dew point in gases

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Lorrach, Germany

Dieter Funken