Patent ID: 8042409

Claim:
A method of measuring mass flow of a first gas component in a gas consisting of two or more known gas components, which gas flows in a pipe in which one or more measurement devices ( 440 , 450 , 460 , 461 , 462 , 465 ; 540 , 550 , 560 , 561 , 562 , 565 ; 635 , 640 , 660 , 661 , 662 , 665 ) is/are arranged in connection with the pipe, where a tubular body ( 410 , 510 , 610 ) is incorporated in connection with the pipe, said method comprising the following steps: determination of one or more gas parameters of the gas by means of the measurement device(s) ( 440 , 450 , 460 , 461 , 462 , 465 ; 540 , 550 , 560 , 561 , 562 , 565 ; 635 , 640 , 660 , 661 , 662 , 665 ), determination of the mass flow of a first gas component by means of the determination of the one or more gas parameters, wherein the determination of the one or more gas parameters comprises a continuous determination of all of those of the gas parameters that are used in the determination of the mass flow of the first gas component and which may vary considerably as a function of the gas composition, pressure and/or temperature, wherein the step of determination of one or more gas parameters by means of measurement devices comprise: determination of the gas temperature T 1 at an inlet of the tubular body; supply of a given amount of energy E to the gas in the tubular body ( 410 ; 510 ; 610 ), and determination of the gas temperature T 2 at an outlet of the tubular body; wherein the one or more measurement device(s) ( 440 , 450 , 460 , 461 , 462 , 465 ; 540 , 550 , 560 , 561 , 562 , 565 ; 635 , 640 , 660 , 661 , 662 , 665 ) comprise a volume percentage measurement instrument ( 440 ; 540 ; 640 ) arranged to measure the volume percentage of at least the first gas component in the gas in order to determine the gas composition for use in the determination of the mass flow of the first gas component, the volume percentage measurement instrument ( 440 ; 540 ; 640 ) being arranged in or in immediate vicinity of the tubular body ( 410 ; 510 ; 610 ).