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Chapter 4 Vacuum Degasser - Operational guide
Page 4-2 MAN 0318
4
Note
If a leak occurs at the connection, tighten the fitting an additional 1/8 turn.
If the leak persists, disconnect the leaking fitting and inspect it. If the nut
and ferrule appear to be in good condition, reconnect the fitting. If the leak
persists, replace the nut and ferrule and repeat the procedure until you
achieve leak-free operation.
The Vacuum degasser maintains a constant vacuum pressure of 50 mm Hg abso-
lute (nominal) by varying the speed of the vacuum pump as needed depending on
the degassing load in the system. The pump is designed for at least 5 years of con-
stant running and has integral in-pump venting, which eliminates the need for
stop-start running (U.S. Patent 6,248,157). The vacuum level and pump speed are
constantly monitored by the microprocessor for changes in operating conditions
which might be attributed to chamber internal leaks. If a potential leak is detected
(if the pump RPM > 300 for 30 minutes), the pump will be shut down and the yel-
low Status LED will flash. The vacuum is maintained as long as the degasser is
powered on. Titrants flowing through the degasser will continue to be degassed so
long as the instrument is on and running.
Also refer to Smart leak detection , later in this chapter.
Turning off / powering down
Turn off the Vacuum degasser when the titrator to which it is connected is not in
use. The vacuum chamber(s) will slowly return to atmospheric pressure when the
unit is powered off. This is accomplished by a small, in-line vacuum bleed and
reduces the possibility of titrant vapours condensing in the vacuum tubing or pump
head.
Flushing - cleaning the degasser
When flushing a line of titrant, the tubing inside the degasser contains a very small
amount of titrant (approximately 480 microlitres). When changing from one titrant
to another; if the final titrant is immiscible with the first, use an intermediate titrant
that is miscible with both the initial and final titrant. Once air bubbles have been
cleared from the titrant line, any further bubbles observed will be coming from the
titrant container or from a leaking fitting.
Note
The MPT-2 Titrator should be primed after the degasser has reached equi-
libration. This will ensure that the titrant in the tubes from the degasser to
the sample tube is fully degassed. The Vacuum degasser uses Teflon AF®
membranes; which fully degas titrants in the time it takes for the volume to
pass through the chamber.
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