Instruction Manual - G85
10
5.7 Gas flow setting
The display can switch between temperature and flow rate.
The flow rate is shown in the display by the integrated digital flow meter in the G85.
Action
Key
Press arrow key either up or
down one time.
Now the flow rate in liter per hour
will be shown.
The flow rate can be adjusted between 0 – 29 l/h.
If the flow becomes larger that 29 l/h the display will indicate “Hi” (see section 5.8).
Action
Key
Press arrow key either up or
down once again to change to
the display of temperature.
5.7.1
Why gassing?
Most of the culture media which are used in assisted reproduction techniques are sensitive
to changes in pH. Culture media must be maintained at a pH about 7.4. This can be
obtained by gassing with atmosphere of 5% or 6% CO
2
.
5.7.2 Working gas pressure
Working gas pressure (inlet pressure on the G85) must be regulated to 0.5 bar by a
reduction valve. The reduction valve must be a high quality unit of the pressure type that
can be adjusted precisely in the 0-1 bar range.
The flow rate on the G85 must be adjusted to a specific level in accordance with the use of
the unit.
Frequent openings of the lids will require higher flow rates.
Note Any use of flow type regulators or inadequate quality pressure type regulators will
cause the flow on the G85 to be unstable and drift.
Below is listed the full recovery rates for CO
2
level in both chambers in minutes.
This can be used as guideline for the use.
Flow (l/h)
*
10
28
50
Time (min) **
12
2.8
0.9
*Flow setting in display of G85.
**Time it will take to recover CO
2
level after a chamber has been opened at the above flow
setting.
