Flanged Flameproof Enclosure:
When the IPS-4 is supplied with the 4660 Sample System option, the flowmeters are installed in
a flanged flameproof enclosure. Care must be taken to assure that all of the bolts are installed
and the flange surfaces are kept in good condition. The minimum flamepath length must be at
least 1 inch (25.4mm) and smooth (250 microinches or better). The gap between the flange sur-
faces with the bolts tightened must not exceed 0.0015 inches (0.0381MM).
Figure 1.
Pressurization system state diagram.
12 | IPS-4 Zone1/Analyzer