Despatch 926E Equipment Manual (C-155)Rev 2/11 - Manual (Page 16)

11
Pressure of Solid, Liquid and Saturated Vapor CO
2
Temperature (

F) Pressure (PSIA) Temperature (

F) Pressure (PSIA)
-140 3.19 -20 215.02
-130 5.39 -10 257.46
-120 8.85 0 305.76
-110 14.22 +10 360.4
-100 22.34 20 421.8
-90 34.05 30 490.6
-80 50.70 40 567.3
-70 74.90 50 652.7
-69.9 75.1
(triple point)
60 747.4
-60 94.75 70 852.5
-50 118.27 80 969.3
-40 145.87 87.8 1072.1
-30 177.97

The solenoid valve used to inject the CO
2
coolant into the test chamber should "pulse" or
actuate rapidly. If the CO
2
valve remains open for long periods of time after pull-down, the
chamber may be leaking coolant, the test object may be introducing substantial amounts of
heat beyond the capacity of the inlet valve orifice, or the temperature set-point may be set
below -73.3

C (-100

F). These conditions can cause "snow" to be introduced into the
chamber with resultant control problems and possible damage to the chamber and contents.
Causes for these conditions should be located and corrected.