Cryogenic Cooling Requirements; Choosing A Coolant - Agilent Technologies 6890 Series Service Manual

Cryogenic cooling requirements

Cryogenic cooling allows you to cool the oven below ambient temperature. A
solenoid valve introduces liquid coolant, either carbon dioxide (CO
nitrogen (N
CO and N
2
assembly if you want to change coolants. The liquid CO
part no. G1565-65510 and the liquid N

Choosing a coolant

When selecting a coolant, consider these points:
• The lowest temperature you need to reach
• How frequently you will use cryogenic cooling
• The availability and price of coolant
• The size of the tanks in relation to the size of the laboratory
• Liquid N
• Liquid CO
CO is the choice for infrequent cryogenic cooling because it does not
2
evaporate and is less expensive than N
much less coolant than a tank of N
of cooling.
Although liquid N
N tanks contain more coolant than do CO
2
for frequent use.
Jun 2001
), to cool the oven to the desired temperature.
2
require different hardware. You must replace the entire valve
2
cools reliably to –80°C
2
cools reliably to –40°C
2
evaporates from the tank regardless of frequency of use,
2
Site Preparation
Agilent 6890 Gas Chromatograph Service Manual
Cryogenic cooling requirements
kit is part no. G1566-65517.
2
. However, a tank of CO
2
and more CO is used for the same amount
2 2
tanks and therefore may be better
2
Gases 520
) or
2
valve kit is
2
contains
2
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