Water trap for a sample gas flow

A water trap for a sample gas flow includes a housing 1 fastened to a holder 2. The housing 1 has a tank 3 for receiving liquids and gases. Above the tank 3, the housing 1 contains a first chamber divided by a first hydrophobic membrane 10. The lower divided part 12 of the first chamber is connected to the sample gas flow via the holder 2 on the inlet side and to the gas space in the tank 3 on the outlet side. The upper divided part 11 of the first chamber is connected to a gas analyzer 4 via the holder 2 and is connected to a vacuum. The housing 1 contains a second chamber divided by a second hydrophobic membrane 20. The lower divided part 22 of the second chamber is connected to the gas space in the tank 3 at a point 18 which is located lower in the direction of the liquid level and relative to the entry of the connection line from the first chamber. The upper divided part 21 of the second chamber is connected to a volume flow meter 8 and to the same vacuum. The free areas through which the gas flows and the pore sizes of the first and second hydrophobic membranes are selected so that the ratio of the gas volume flow through the first and second hydrophobic membranes is in the range of 5:1 to 20:1.