Patent ID: 8012741

Claim:
A biogas measuring device, comprising: a bioreactor with an agitator therein, a gas volume meter connected to the bioreactor via a gas conduit which permits biogas to be transported from the bioreactor to the gas volume meter, said gas volume meter comprising a housing having a measuring chamber which has a defined measurement volume (V REF ), a gas inlet valve controlling a gas inlet into the measuring chamber, a gas outlet valve controlling a gas outlet from the measuring chamber, a pressure sensor for detecting the atmospheric pressure (P a ), a differential pressure sensor for detecting a differential pressure (dP) between a gas pressure in the measuring chamber and atmospheric pressure (P a ) or a current system pressure (P 2 ), a measurement, control and evaluation unit for determining gas volumes measured by the gas volume meter for successive measurement cycles, wherein said measurement, control and evaluation unit is configured to operate said gas volume meter and said bioreactor to perform each measurement cycle according to the following steps i) introducing a gas quantity into the measuring chamber by opening the gas inlet valve until a defined threshold gas pressure is reached, then ii) closing of the gas inlet valve when the defined threshold gas pressure is reached, then iii) measuring temperature (T 1 ) in the measuring chamber, then iv) opening of the gas outlet valve for an expansion time, and then v) closing of the gas outlet valve ( 14 ), wherein the bioreactor is gastight, such that all gas volumes generated in the bioreactor are detected in the measuring chamber by the gas volume meter, a cooling element is provided on the gas conduit, and the measurement, control and evaluation unit controls the cooling element to reduce water vapor concentration in biogas transported from said bioreactor to said gas volume meter so that a measured gas volume of a measurement cycle is normalized to standard conditions.