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19
Data
Filtrate Volume
The HTHP filter press has a filtration area of 3.55 in
2
(22.9 cm
2
). This is half
the area of a standard filtration test, which is 7.1 in
2
(45.8 cm
2
). To compare
the results of this test to a standard filtration test, double the total filtrate vol-
ume collected.
V
F
= 2 (V
30
)
Where:
V
F
= Standard Filtrate Volume (mL)
V
7.5
= Filtrate volume collected after 7.5 minutes
Spurt Loss (Optional):
Spurt Loss is the amount of filtrate collected before the filter cake has had a
chance to form and is expressed in millimeters. To calculate the spurt loss,
use the following equation:
V
1
= 2 [V
7.5
- (V
30
-
V
7.5
)] = 2 (2V
7.5
- V
30
) = 4V
7.5
- 2V
30
Where:
V
1
= Spurt Loss
V
7.5
= Filtrate volume collected after 7.5 minutes
V
30
= Filtrate volume collected after 30 minutes
Filter Cake
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
in (0.8 mm). A ruler
with the “zero mark” at the very edge of the ruler is useful here. Cake descrip-
tions may be subjective and such notations such as hard, soft, rubbery, and
fine, etc. convey adequate information on cake quality.
