What standard process control features should be considered, and do they cover N.F.P.A and O.S.H.A code requirement?
A main power disconnect which disables all electrical power in the event access is required inside control panels should be installed. All heating zones should have individual manual operating controls, along with separate and redundant manual resettable over temperature controls. An over temperature situation should sound an audible alarm and disable power to all heating zones. The vacuum pump and chamber vacuum pressure should be monitored, and an adjustable alarm should be provided for loss of vacuum, which disables power to the vaporizer if pressure rises beyond the set point. The cold trap should have a local temperature readout, as well as a separate thermocouple and remote control, which monitors the trap temperature. It should be interlocked with the initial pump start-up and sound an audible alarm, should the cold trap rise above -65 C. Some type of window or site port should be provided on the chamber, for operator observation of the process. An adjustable speed control shoul
