Endress+hauser Conducta Gmbh+co. Kg

Endress+hauser Conducta Gesellschaft Fur Mess- Und Regeltechnik Mbh+co. Kg

Oliver Bettmann

Ulrich Kathe

Thomas Schipolowski

Björn Emling

An apparatus for determining the content of at least one oxidizable constituent of an aqueous, liquid sample, comprising a high temperature reactor for decomposing the liquid sample and forming a gaseous mixture, which contains at least the constituent as a gaseous oxide, wherein the high temperature reactor has a liquid inlet for delivery of the liquid sample and a gas inlet for delivery of a carrier gas, and is connected via a gas discharge with an analysis chamber, wherein a condensing unit is placed in front of the analysis chamber for condensing water from the gas mixture, wherein, during operation of the apparatus, a gas stream of the carrier gas with the gas mixture of the high temperature reactor passes via the gas discharge and the condensing unit into the analysis chamber, and wherein, between the gas discharge and the condensing unit, a heatable filter unit is interposed for removal of salts and/or metal oxides from the gas mixture, and the gas discharge, the filter unit and optionally connecting elements arranged between gas discharge and filter unit are thermally insulated and/or equipped with heating elements in such a manner that their temperature during operation of the apparatus is settable to more than 100&#xb0; C.

Apparatus for determining content of at least one oxidizable constituent of an aqueous sample

A method for determining the number of drops metered with a drop frequency into a reactor, especially in a high temperature decomposition system for analyzers, wherein a gas stream is flowing through the reactor. There exists in the reactor a temperature, which is greater than the boiling temperature of the liquid, and a drop metered into the reactor transforms at least partially into the gas phase following entry into the reactor, especially due to heat transfer from contact with a surface within the reactor, especially directly after contact with the surface within the reactor. With a sampling rate, which is greater than the drop frequency, a sequence of pressure signals dependent on pressure within the reactor is registered, and, from the sequence of pressure signals or from values derived therefrom, the number of drops metered into the reactor is ascertained.

Method for determining number of drops

A method for operating an analytical apparatus for determining concentration of an analyte, especially an oxidizable substance, in a sample liquid, comprises the steps of: placing the analytical apparatus in maintenance operation; operating a metering system, which includes a pump, especially a peristaltic pump, and a supply line, for metering single volume units of a sample liquid from a source via the supply line into a reactor, wherein there exists in the reactor a temperature, which is greater than the boiling temperature of the sample liquid, so that a volume unit of the sample liquid metered into the reactor transforms at least partially into the gas phase following entry into the reactor, especially due to heat transfer from contact with a surface within the reactor, especially directly after contact with the surface within the reactor, and wherein a carrier gas is flowing through the reactor; registering at least one measuring transducer signal for detection of the transforming of the volume unit of the sample liquid into the gas phase, and deriving, with application of the measuring transducer signal, a signal correlated with an instantaneous operating state of the metering system.

Method for operating an analytical apparatus

A method for monitoring the concentration of water borne substances in an aqueous medium, by introducing a defined amount of the aqueous medium into a gas circulatory system of an analytical apparatus which extends through a high temperature reaction chamber and a measuring chamber. The introducing of the aqueous medium occurs upstream of the high temperature reaction chamber or into it. The aqueous medium is evaporated in the high temperature reaction chamber, the water borne substance with at least one reaction partner in the high temperature reaction chamber reacts to a gaseous reaction product, and a current value of a measured variable is registered, which is a function of the concentration of the chemical species of the reaction product in the gas circulatory system. The concentration of the chemical species of the reaction product in the gas circulatory system depends, on the one hand, on a time-dependent state of the gas circulatory system and, on the other hand, on the concentration of the substance in the aqueous medium; ascertaining the concentration of the substance in the aqueous medium by applying the current value of the measured variable, wherein, in the ascertaining of the concentration of the substance in the aqueous medium, the contribution to the concentration of the chemical species of the reaction product in the gas circulatory system by the state of the gas circulatory system is ascertained on the basis of a model of the state, and a correction of the concentration of the chemical species of the reaction product in the gas circulatory system occurs on the basis of this contribution.

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Russelsheim, Germany

Oliver Bettmann