Shellab SCO10W-2 - Manual (Page 13)

13
5.9 CO
2
Supply System and Control System: The CO
2
system is rated for pressures between 15 to 20
PSI which should never be exceeded at any time. Prior to any attempt to hook up or run the CO
2
control system, the water jacket must be filled and the temperatures adjusted as noted in section 5.7.
Figure 3
A. The CO
2
inlet fittings are located at the back of the unit near the top (see figure three). They
are marked CO
2
TO CHAMBER. You have the option of using one or two tanks. A supply
hose with in-line CO
2
filter (supplied with your accessories) connects from each fitting to a
CO2 tank and regulator. If you plan to use only one tank, it does not matter which fitting you
connect the supply hose to, and the remaining fitting is left open. If you plan to use two tanks,
set the output pressure of one tank to 15 PSI and the other tank to 20 PSI. The internal tank
switch will use up the 20 PSI first and then switch over to the 15 PSI tank. It does not matter
which tank is attached to which fitting. When the 20 PSI tank is empty its output pressure
gauge will indicate 15 PSI. At this time the empty tank can be replaced. Note that there are
no alarms to indicate when the tanks are empty, so operators should monitor gas
consumption.
B. It is highly recommended that a good quality 0-60 PSI output range DUAL STAGE pressure
regulator be used on the CO
2
tank. The dual stage regulator will have two pressure gauges.
The high pressure gauge (0-4000 PSI) will indicate the pressure within the tank. The low
pressure gauge (0-60 PSI) will indicate the output pressure on the supply hose to the
incubator. Do not use single stage regulators. They will not supply a stable pressure. Just
because a regulator has two gauges does not mean that it is a dual stage regulator. Insure
that you are using a dual stage regulator.
C. It is normal for the high pressure gauge on your regulator to start out reading 800 to 1000 PSI
with a full tank. The reading will drop to 500 to 800 PSI quickly and will stay there for most of
the duration of the tank. At the end of use the pressure will drop quickly to zero to indicate that
the tank is completely empty. Pure CO
2
is in a liquid state in the tank, and a constant vapor
pressure is generated in the tank above the liquid level. The CO
2
is drawn off of the top as a
gas. The same vapor pressure is maintained as long as any liquid is left in the tank. When
the last of the liquid has evaporated into gas then the pressure will drop rapidly as the gas is
drawn off.
D. Only medical grade CO
2
should be used in your incubator. The use of any lesser grade may
damage your incubator and void your warranty.