[en] The sample is taken from a bypass line. A block of valves with four outlets is used for this purpose, where there is always part of the concentrate in one valve chamber. The valve chamber can be shut off from the bypass line using two valves in the outlets. The contents of the chamber are then flushed with a solvent (e.g. water) into a mixing container, via two of the other valves in the other two outlets, and is diluted in the ratio 1:99. The actual sample extraction is via a sample vessel, which can be connected to the mixing vessel. The process requires no direct cooling, and the dilution reduces the danger from the substance. (orig./PW)