Flow Control - GE 9100c Technical Reference Manual

2.2.3 Flow control

WARNING
Hypoxic guard system
M1207026
M1207027
Reproduced from the electronic master in MATRIX
Needle valves (one for each gas) adjust gas flow. Clockwise rotation
decreases flow. Counterclockwise increases flow. A hypoxic guard
system sets the maximum ratio of N
The hypoxic guard sets a minimum O
the common gas stream.
The hypoxic guard is an internal system that is not serviceable. It
helps control an approximate minimum 1 to 3 ratio of flow between O
and N O. When engaged, the O
2
• An increase in N
2
• A decrease in O
2
Higher concentrations of O
not engaged: either by reducing the N
engagement or by increasing O
When the N O flow is below the point of engagement, increasing the
2
N O flow turns the O
2 2
the guard is engaged, turning the N
(increase in N O flow) also turns the O
2
(increase in O flow) to maintain a nominal 25% minimum O
2
concentration.
Decreasing the N O flow from the engagement point rotates the O
2
sprocket away on the O
004 MANUAL−DOC, Technical Reference Manual, Technical Reference Manual for 9100c, English
2 Theory of Operation
O to O .
2 2
concentration in
2
and N O knobs turn together:
2 2
O flow causes an increase in O
flow causes a decrease in N
are possible when the hypoxic guard is
2
O flow below the point of
2
flow above the point of engagement.
2
sprocket without changing the O
O flow control counterclockwise
2
knob counterclockwise
2
knob, increasing the O
2
2
flow.
2
O flow.
2
flow. Once
2
2
2
concentration.
2
2-7