Millipore Pellicon Single Pass TFF - Page 25

Pellicon
®
Single Pass TFF Accessories Installation and User Guide 25
Open the permeate line of the cassette being measured and
close the permeate lines of the cassettes not being measured.
Use the retentate valve to adjust the outlet pressure of the
cassette being measured. Measure NWP. Repeat the process
for all remaining cassettes/sections. Ensure each individual
cassette is measured under similar flow and pressure
conditions. Use the same feed flow rate and adjust the
retentate valve for each cassette NWP measurement so that
the resulting outlet pressure value is similar for all.
Three-section NWP test setup for individual sections
Calculate the NWP:
This equation yields units
LMH/bar or LMH/psi [liters/m
2
x hours x bar or psi]
J
f
= permeate flux
TMP = Trans-membrane pressure
Calculate:
R = Permeate flow rate in L/hour
P in = Feed pressure in bar or psi
P out = Retentate pressure in bar or psi
T = Water temperatures in °C
Pp = Permeate pressure (if non-zero) in bar or psi
A = Total filter area in m
2
F = Temperature correction factor from the table in this section.
Feed
Feed pump
Separate permeate lines for each
Retentate valve
P
2
P
1
P
3
P
4
Section 1
Section 2
Section 3
NWP =
R
x
F
A
x
P
in
+ P
out
2
-P
p
J
f
TMP
=