Method of sampling a cryogenic liquid

A method of taking a cryogenic liquid sample, with a cryogenic liquid sampler comprising:

• a sampler vessel comprising an inner volume, and an inner wall,
• a cryogenic liquid inlet conduit in fluid connection with an inlet valve,
• a weir tube in fluid connection with the inlet valve,
• wherein the weir tube has a top plug and at least one weir hole through a circumferential surface of the weir tube,
• wherein the weir tube extends into the inner volume,
• wherein a first cryogenic liquid level is the distance along the weir tube between the inner wall and the at least one weir hole,
• a cryogenic liquid outlet conduit in fluid connection with the inner volume and in fluid connection with an outlet valve, and
• a purge tube in fluid connection with the outlet valve,
• the method comprising;
• a) closing both the inlet valve and the outlet valve,
• b) connecting a cryogenic liquid source to the cryogenic liquid inlet conduit, and introducing cryogenic liquid into the cryogenic liquid inlet conduit;
• c) opening both the inlet valve and outlet valve, thereby introducing cryogenic liquid into the sampler vessel inner volume, wherein the cryogenic liquid has a free surface;
• d) closing both the inlet valve and the outlet valve after cryogenic liquid flows from the purge tube;
• e) disconnecting the cryogenic liquid source from the cryogenic liquid inlet conduit;
• f) opening the inlet valve, thereby allowing cryogenic liquid to flow from the cryogenic liquid inlet conduit;
• and
• g) closing the inlet valve after the free surface in the sampler vessel inner volume drops below the top of the first cryogenic liquid level, and the cryogenic liquid flow stops.