16
NITROUS AND OXYGEN FLOW TUBE INDICATORS
The Nitrous and Oxygen flow tube indicators are factory calibrated separately and indicate the
lowest to highest flow of Oxygen with tube markings at 1 and 10 L/min, and lowest to highest flow
of Nitrous Oxide with a tube marking at 1 L/min. The glass tubes are secondary indications of flow
(digital display is primary) and the Total Flow is the addition of the two indicated ball float
positions in the tubes.
Each tube has a small Circle Flow Guide which indicates 3 L/min of flow when the center of the
float is set at the center of the circle and a larger Circle Flow Guide which indicates 6 L/min of flow
when the center of the float is set at the center of the circle.
Ball float height (flow) of the Oxygen tube has 1:1 proportionality to the ball float height (flow) of
the Nitrous tube. Thus, given any line-of-sight reference on the front panel, when the ball floats
are at the same height, the percent Nitrous Oxide is 50%. Similarly, when the Nitrous ball float is
lower than the Oxygen ball float, the percent Nitrous Oxide is less than 50%. When the Nitrous
ball float is roughly one-half the height of the Oxygen ball float, the percent Nitrous Oxide is
roughly 33%. The chart below may be used as a guide.
USAGE DURING POWER OUTAGE
Note:
If the power is interrupted to the unit, the unit will continue to deliver the same mixture
setting during the power outage but the device will not display the digital readouts for the % N
2
O
and Total Flow. The knobs may be adjusted to move the ball float to the desired positions. When
safely possible, discontinue the procedure using normal delivery techniques as described below.
Refer to Monthly Calibration Check which describes the use of the Circle Flow Guides and how to
read the ball float position using these guides.
1. Rotate knobs to appropriate positions using the chart and figure below as a guide.
2. Place the center of the ball float at the desired setting for the % N
2
O and the desired
setting for O
2
/ Total Flow to achieve the %N
2
O Setting. Refer to sections on “Directions
for Use” and “Basic Delivery Technique”.
3. When the procedure is nearing completion, decrease the amounts of N
2
O by turning the %
N
2
O (left knob) and then terminate the flow of N
2
O and deliver 100% O
2
to oxygenate the
patient.
4. When the procedure is completed, turn the On / Standby switch to the STANDBY (Off)
position until power is restored.
Flow Tube Indicators
(Note: Read Center of Ball Float)
% N
2
O
Setting
Ball Float
Position for
% N
2
O
Ball Float
Position for
O
2
/ Total Flow
50%
3 L/min
3 L/min
50%
6 L/min
6 L/min
33%
3 L/min
6 L/min
67%
6 L/min
3 L/min
6 L/min
Circle Flow Guide
3 L/min
Circle Flow Guide
1 L/min
10 L/min