Siemens PGC 302 Edition II Manual page 199

Adjusting the live switching
Adjusting the live switching
IMPORTANT
For safety reasons the function Backflush
was previously switched on if the solenoid
valve MV
MV . In other words: MV
Cut
MV OFF = straight!
Back
We have retained this so that you need not
be concerned with different versions.
However this can be changed in two
manners using the configuration software:
- The valves can be configured as inverted
- The names of the valves can be changed,
e.g. into No backflush .
In this description we consider the non-
modified version!
Adjusting the live switching
There are three outlets!
During the adjustment, peaks cab be output from the
live T-piece via three outlets:
Cut outlet
Flushing outlet
Column B outlet.
Therefore all three outlets must be observed! This is
easiest using monitor detectors (version 1).
If you do not have a monitor detector, the outlet Purge
outlet must be routed to the main detector in straight
operating mode (version 2), or the outlet Cut outlet in
cut operating mode (version 3). To do this, connect the
respective capillary from the outlet of needle valve
NV or NV
Cut outlet Purge outlet
1
The following applies in all cases: the peak via column
B always arrives later than the peaks via the cut or
purge outlet. Therefore: detailed consideration is
necessary, especially with versions such as Distribu-
tion!
6 - 8
was OFF! The same applies to
Back
ON = straight,
Cut
to the detector.
2
A
B
3
The suitable test substance
The test substance for the adjustment should generate
only one peak without a short retention time. An alkane
with approximately the same boiling point as the
measured component is appropriate. Example: methane
for gas injection or hexane for liquid injection.
P
A
MV
BACK
NV
BACK
BYPASS
MV
BACK
Column A
NOTE:
The solenoid valve MV
valve in the case of capillary switching!
Off we go!
Install columns. See Installation of columns on live T-
piece. Check everything for leaks.
1. Adjustment of flow through column B
Measure flow at outlet of column B
Set P
M
– according to the application data
– or look up the optimum flow in the tables pro-
vided by the column manufacturer, measure and
set P accordingly
M
Set P according to the equation
A
= P
A P
A M
Set initial temperatures
2. Adjustment of needle valves
A
Set split. See Injectors.
Completely open NV
Set NV
Cut outlet
– according to the application data
– or to 10 ... 70 ml/min at the outlet Cut outlet
(optimum, approx. 5 * flow
and 10 ... 30 ml/min at the outlet Purge outlet
NOTE:
If you use a monitor detector, it is connected to the outlet
Cut outlet using a capillary. The needle valve NV
not present in this case. The flow is adjusted by shortening
the capillary.
P
M
NV NV
CUT STRAIGHT
Live T-piece
MV
CUT
NV NV
PURGE
CUT
OUTLET
OUTLET
Column B
____ _
is usually replaced by a needle
Back
Length
Column_A
+ × P
M
Length
Column_B
and NV
Cut Straight
and NV
Purge outlet
)
A-column
is
Cut outlet
live.chp, Issue August 17, 1999