I have an old 600 gallon liquid nitrogen dewar. I'm worried that it is possible for the pump on the truck that fills it to over pressurize the vessel. Its MAWP is 250 psig. BOC has the contract for filling our dewars (tanks), however I have not been able to get a pump curve for one of their trucks from them. They tell me not to worry because the relief valves/rupture discs will protect the vessel. I disagree because the relief devices were sized for fire, not for truck fill rate. A few people had told me that the truck pumps can deliver 200 GPM LN2 at 350 psig? Does anyone have an idea of what these delvery trucks can actually deliver?