Method and apparatus for taking slurry samples from a continuous gravity process flow, and use of apparatus

An apparatus for taking slurry samples from a continuous process gravity flow of a pressureless open-channel type flowing in an open launder or in a closed flow channel, said process flow having a first width, the apparatus comprising a first sampling unit for taking a primary sample flow from the process flow, and a second sampling unit for taking a secondary sample flow from the primary sample flow,

• wherein the first sampling unit comprises substantially vertical first side walls defining a first inlet opening and a first outlet opening therebetween, said first side walls diverging in direction towards the first outlet opening, and in that the first inlet opening is substantially narrower than the first width of the process flow, thereby causing the liquid level of the primary sample flow to be lower than that of the process flow, characterized in that the first sampling unit and the second sampling unit comprise venting means adjacent the upper ends of the side walls to allow equalizing of the atmospheric pressure prevailing inside and outside the first and second sampling units above free liquid levels of the primary and secondary slurry flows along the entire lengths of the sampling units to form pressureless open-channel type flow paths for the primary and secondary sample flows.