Helium Purifier--adsorption Type.
U S Pat 3 683 589 1972 Aug; :
An automatic apparatus is described for preparing continuously helium having <1 ppb impurities. Two adsorbent columns are used, one of which is being regenerated while the other is adsorbing impurities. This operation involves a 2-part purification instrumentality having in each of its parts an adsorbing material generally filling an enclosure positioned under an inverted container forming an insulator shroud. Gas periodically trapped under this shroud constituting a superior heat shield making possible dual temperature operations. Both parts are adapted to function together suspended within liquid nitrogen, each operating alternately as low-temperature helium purifier and as a relatively high-temperature regenerator of the adsorbent material contained therin. Continuous cyclic operation of the apparatus, which enables uninterrupted productive operation, is predetermined by the setting of a program control mechanism employing timer driven cam actuators for switches in energizing circuits to valve actuating solenoids and heaters cooperatively associated with the respective enclosures.
U.S. Pat. 3,683,589; Aug. 15, 1972; Chem. Abstr. 78:45,772E