11
Connecting the Pneumatic Pump K–1900
Required Compressed Air
250 ml
7 bar
6 bar
5 bar
4 bar
3 bar
2 bar
1 bar
Required compressed air
1000 ml
7 bar
6 bar
5 bar
4 bar
3 bar
2 bar
1 bar
-1
F
low
Rat
e
[
m
l
m
in
]
Li
qu
id
P
re
s
s
u
re
[
ba
r]
L
iq
u
id
P
re
ssu
re
[
b
ar
]
900
600
300
0
0
300
600
900
Flow Rate [ml/min]
Fig. 9
Interdependence of delivery volume and eluent pressure for the 250 ml pump
head
210
140
70
0
0
800
1600
2400
Flow Rate [ml/min]
Fig. 10
Interdependence of delivery volume and eluent pressure for the 1000 ml pump
head
Calibration for Constant Flow
If you want to use the pneumatic pump as a delivery pump with constant
delivery volume, you need to calibrate it.
Fig. 11 shows typical calibration curves for two different columns with different
pressure losses along the column for the 250 ml pump head. In this figure
column 1 has a lower back pressure than column 2 at same flow rate, so it is
possible to obtain higher flow rates with the same required air pressure on the
column 1 compared to the column 2.
For the calibration you have to measure the flow rate at different required air
pressures from 1 up to 7 bar (up to 4.2 bar with the 100 ml pump head)
120
80
Column 1
40
Column 2
0
1
2
3
4
5
6
7
Fig. 11
Typical calibration curves of the Pneumatic Pump K–1900 for two different
columns (250 ml pump head)
