10. Collect the filtrate for 30 minutes maintaining the selected test tempera-
ture within ± 5°F (± 3°C). If the back pressure rises above recommend-
ed setting during the test, reduce the pressure by carefully opening the
valve on the receiver and drawing off some of the filtrate into the gradu-
ated cylinder. When the pressure is back down to the recommended
setting, close the valve.
11. At the end of the test, close the top and bottom valves on the cell.
Unscrew the regulator T-screws and open the needle valves on the
pressuring assembly and the back pressure receiver to release all of
the pressure.
12. Remove the back pressure receiver and drain any remaining filtrate into
the graduated cylinder. Correct the total filtrate volume collected to a
standard filtration test area of 7.1 in
2
(45.8 cm
2
) by doubling the filtrate
volume collected in 30 minutes. Record this total filtrate volume (dou-
bled), and the temperature, pressure, and time.
13. Disconnect the primary pressure assembly by lifting the lock ring and
slipping the pressure assembly off the cell coupling. Remove the cell
from the heating jacket and allow it to cool to room temperature or
quick cool the cell by immersing it in cool water. Keep the cell in an
upright position during this procedure. When the cell has cooled, slowly
open the two needle valves to bleed off the cell pressure.
Pressure inside the sample cell will still be approximately 500 PSI
(3,450 kPa). Keep the cell upright and cool it to room temperature
before disassembling. The cell must be cool for at least one hour
at room temperature or at least 10 minutes in cool water before
loosening the cap locking screws and removing the cell cap.
14. Invert the cell and loosen the cell cap screws with the Allen wrench.
Use extreme care to save the filter paper and deposited filter cake.
Discard the fluid inside the cell, and retrieve the filter cake.
15. Wash the filter cake on the paper with a gentle stream of water.
Measure and report the thickness of the filter cake to the nearest 1/32"
(0.8 mm).
16. Clean and dry the apparatus thoroughly after each use. Inspect all o-
rings and replace if necessary.
OFITE, 11302 Steeplecrest Dr., Houston, TX 77065 USA / Tel: 832-320-7300 / Fax: 713-880-9886 / www.ofite.com
10
Important
!
