This nickel-plated brass container contains a nickel-plated copper cooling coil with one end connected to a purging valve and a pressure control valve and the other end suitable for connecting to the vessel being sampled.

In operation the cooling unit is filled with solid carbon dioxide and the inlet is connected to the sampling point. The sample is drawn into the cooling unit until vapour overflow is observed after which it is isolated by closing the valves. Liquefied gas is then drawn from the bottom of the cooling unit via the outlet tube which may be connected to a pressure sampling, vapour pressure cylinder or similar test vessel.