Patent ID: 8353194

Claim:
A method for the indirect determination of a waste gas rate of a waste gas in a metallurgical process, comprising: adding helium as a reference gas to the waste gas; measuring a helium flow rate; mixing the reference gas and the waste gas such that a substantially homogeneous distribution is achieved; taking a sample of the mixed reference gas and waste gas; and analyzing the sample by a mass spectrometer to perform a reference gas analysis and nitrogen analysis of the waste gas, while taking into account the added amount of the reference gas, wherein the waste gas rate is determined by the formula: Q W = 1 He - He Air ⁢ N 2 N 2 ⁢ Air ⁢ Q HeB , where Q W is the calculated waste gas rate Nm 3 /min; N 2 , He are respective waste gas nitrogen, helium concentrations; N 2Air , H Air are nitrogen, helium concentrations in air; and Q HeB is the measured helium flow rate Nm 3 /min.