OFITE, 11302 Steeplecrest Dr., Houston, TX 77065 USA / Tel: 832-320-7300 / Fax: 713-880-9886 / www.ofite.com
12
Recommended Minimum Back Pressure
Test Temperature
Vapor Pressure
Minimum Back Pressure
°F
°C
PSI
kPa
PSI
kPa
212
100
14.7
101
100
690
250
121
30
207
100
690
300
149
67
462
100
690
350
177
135
932
160
1,104
400*
204
247
1,704
275
1,898
450*
232
422
2,912
450
3,105
500*
260
680
4,692
700
4,830
*For tests above 400°F, use Teflon o-rings.
26. Set the mixing speed using the speed control knob on the control box.
The current speed of the motor will be displayed on the tachometer.
27. After the one-hour heat time, increase the “Main Pressure” to 500 PSI
(3,448 kPa) more than the back pressure.
28. Open (loosen) the bottom valve stem ½ turn to initiate filtration.
29. To collect filtrate, carefully open the ball valve on the bottom of the back
pressure receiver while holding a graduated cylinder up to the valve port.
Close the valve immediately after the pressure begins to decrease and
the filtrate is collected.
Collect filtrate at 10 seconds, 1 minute, 7.5 minutes, and 30 minutes.
The initial 10 second collection is precautionary in nature, as a fluid
with little filtration properties may fill up the 15 mL receiver tube almost
immediately, potentially damaging the regulator. Do not record the 10
second collection as a separate notation, but do record the volume
collected at the other time intervals. At the end of the test, close (tighten)
the top and bottom valve stems to seal off the cell.
30. Turn the regulators counterclockwise to close off the flow of pressurized
gas.
31. Set the “Temperature Controller” to 0 and turn off the “Heat” switch.
32. Turn the “Motor” switch off and unplug the magnetic drive.
33. Begin cooling by opening the valve on the back of the heat jacket a
quarter-turn.
34. Allow the filtrate to cool for at least five minutes. Open the outlet valve
on the back pressure receiver to collect all of the filtrate in the graduated
cylinder.
