Abstract: Gasmeter for determining a flow rate of gas within a channel is provided. The gasmeter includes a channel for passing through it a flow of gas along a first sensor and a chamber which is arranged for receiving and containing at substantially stand still gas from the channel and in which a second sensor is arranged. The sensors are heated during heating periods and subsequently let cooled down in cooling periods. The cooling rate of the sensors is determined and are used to calculate a value of the flow rate through the channel which is compensated for change of density of the gas.

Abstract: The flow rate of a medium flowing through a channel is measured by using a number of measurement sites along which the medium flows continuously at different velocities. The heating of the medium at the measurement site and the measurements of the temperature changes at the measurement sites are used to measure the rate of flow. Calibration information for the flow measurement for each measurement site is utilized to establish a rule which would include information about the measurement accuracy over the measurement range for each measurement site. The flow rate to be measured is established upon the basis of the measurement result of a measurement site which gives the greatest measurement accuracy according to the predetermined rule. The measurement of the flow at a measurement site comprises heating the medium during a first interval and during a second interval subsequent to the firest interval the temperature reduction is monitored at the measurement site.