Once a representative sample has been extracted from the pipeline, it must remain representative in the sample receiver and when analysed in the laboratory. The standards recommend the use of either fixed or variable volume depending on the properties of the fluids being sampled. Liquids with a high RVP would normally be stored in variable volume receivers minimising the risk of losing light-ends. For practical purposes portable receivers are preferred as the batch sample can be transferred to the laboratory allowing the sub-samples for analysis to be drawn under controlled conditions rather than in the field.
Sample receivers should be designed so that they are easy to clean and have no voids or water traps. The internal finish should inhibit water retention. Receivers should incorporate a facility to mix the contents of the receiver prior to the extraction of a sub-sample for analysis, as it is not possible to sufficiently agitate samples manually. This is normally performed by connection to an external mixer loop that homogenises the sample with minimal heating, which can cause loss of light ends. The analysis sample can be drawn using a septum or valve from the mixing loop.
Receivers should be suitable to be used on a weighing system or include a method of measuring the performance of the sampling system during the batch.
