Abstract: An in-line blender for blending components, in the form of liquid or other fluent materials including a pipeline having a plurality of injection points, each injection point being connected to a set of selector valves and each selector valve being connected to a separate component source. Only one of these selector valves at a time is connected to the injection point. Between the set of valves and the injection point there is mounted a metering apparatus in the form of a positive displacement pump and a meter 14.

Abstract: Liquid is removed from a liquid transfer line 1, for example a crude oil pipeline, through a sampling probe 2 and returned to the transfer line 1 via a return loop 3 and pump 5. At the outlet 4 of the return loop to the transfer line the returning liquid enters the liquid in the transfer line as a jet or jets which agitates the liquid to a substantially homogeneous mixture. The outlet 4 is upstream of probe 2 so that in operation the liquid entering the return loop 3 is uniformly mixed and a representative sample may be withdrawn from the return loop 3 into sample outlet through valves 9 and 10. To ensure mixing of sedimentary layers in the transfer line 1 the jet from outlet 4 is directed upwardly into the transfer line.