Reliable, troublefree pump operation is the key to low-cost cryogenic liquid pumping, according to "FrostByte," a newsletter published by Cryogenic Industries, Murietta, Calif. When installing either reciprocating or centrifugal cryogenic liquid pumps, careful upfront planning can mean the difference between long-term reliability or excessive maintenance and consequent downtime, the newsletter reports, listing several considerations that apply equally to reciprocating and centrifugal pumps.
Flexible lines connecting the piping to the suction and discharge fittings must be used to take up the stress or shrinkage when the system is cold. To ensure that the flexible lines are adequate, the pump should be bolted to the pad after cool down, which is not the normal practice on reciprocating pumps. This procedure relieves any stress in the piping, allowing the pump to be practically stress-free when in operation.