Master panel board in the hydrogen liquefication plant of the NBS-AEC Cryogenic Engineering Laboratory. The two sections on the left were identical in function and were used alternatively, depending on which of the two liquifiers was in operation, to control the flow of hydrogen through the liquifier. The larger dials in these sections recorded and controlled the level of liquid hydrogen and liquid nitrogen in the liquifiers and purifiers, regulated pressure, and recorded temperature. The smaller dials indicated pressure. The control for the Joule-Thomson expansion balbe was the central of the three valve controls located just below the row of four smaller dials. The end panel section (at right) contained additional temperature recorders, indicators to show the amount of gas in external gas holders, a system of lights to indicate those parts of the system which were in operation, and the controlls for an emergency venting system. The portion of the panel board not shown contained the controls and indicating dials for devices which determined the oxygen and nitrogen content of the hydrogen. [From "NBS-AEC Cryogenic Engineering Laboratory," in NBS Summary Technical Report 1736, August 1953.
National Institute of Standards and Technology
National Institute of Standards and Technology