Varian 450-GC, Руководство пользователя

Страница: 122 / 205

Injectors – 1079 PTV Injector
Page: 184 User Manual 450-GC Varian, Inc.
Setting 1079 PTV Gas Flow Rates
The gas flow rates for the 1079 PTV Injector can be set using manual
pneumatics or Electronic Flow Control. Note that a positive flow through the
column must be set before heating the column.
Do not heat the col umn ov en above 50 ng through
the column. The column phase can be irreversibly damaged by exposure to
oxygen at elevated temperatures. Allow 10 – 15 minutes to purge the column
before heating.
EFC Pneumatics
Type EFC21 used with the 1079 PTV Injector allows the user to set a constant
column head pressure, build a pressure program, or set a constant column
flow. In addition, a split ratio can be set or time programmed. A pressure
program is typically used to maintain the column flow at a constant value while
temperature programming the column oven. When Constant Flow Programming
is enabled, the pressure program needed to maintain constant flow is derived
whenever the method is loaded.
The 1079 PTV is a pressure-controlled Injector; thus the column flow decreases
with increasing column temperature if the pressure remains constant. EFC
method parameters and status are accessed via the FLOW/PRESSURE
key on the 450-GC keyboard.
C without carrier gas flowi