Section 2
General Description
Flowmeters
Flowmeters, located directly above their corresponding flow control
valves, display the delivered flow rate of each gas in the fresh gas
mixture. Dual flowmeter tubes (fine and coarse) are used in tandem for
oxygen, nitrous oxide, and air (if provided). When other gases are
supplied, single flowmeter tubes are used. All flowmeters are labeled at
each end of the flowtube. A typical flowmeter arrangement is shown in
the Flowmeter and Pressure Gauge Assembly figure earlier in this
section.
Each flowmeter has a float indicator. To determine the flow rate, read
the flowmeter scale at the center of the float.
Low-Flow
Flowmeters
(Optional)
For low-flow anesthesia, the Narkomed 2B can be configured with low-
flow, dual-tube flowmeters for oxygen and nitrous oxide. These
flowmeters function the same way as the standard dual-tube flowmeters,
but they are calibrated to provide greater resolution for low-flow
anesthesia.
Minimum Oxygen
Flow
The oxygen dispensing system incorporates a calibrated bypass flow of
150 ±50 ml/min (at 50 psi pipeline pressure), which delivers this volume
of oxygen even if the oxygen flow control valve is fully closed.
Flow Control
Valves
A needle valve is located below the fine flowmeter tube for each gas.
This valve is used to adjust the flow of gas. Turning the valve knob
counterclockwise increases flow; turning the knob clockwise decreases
flow. A zero stop prevents damage to the flow control valve seats. If
necessary, a North American Dräger qualified technical service
representative can readjust the stop.
Each flow control knob is identified by its color code and chemical
symbol. The oxygen flow control valve is also touch-coded with a deeply
fluted knob.
CAUTION: The flow of oxygen cannot be completely shut off (see
“Minimum Oxygen Flow” earlier in this section). Do not
force the oxygen flow control knob in an effort to shut off
the minimum flow; forcing the knob can damage the valve
seat.
2-6
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