Mindray WATO EX-55, Service Manual

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4.3.1 Flow Calibration (user)
NOTE
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The measurements performed by the flow sensors may be affected by the
environment where the sensors are used. After the sensors have been used for a
long time, great deviations may occur to the measurement results and tidal volume
control as well. This problem can be fixed through flow sensor calibration.
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When replacing sensors or after re-calibrating sensors, you need to calibrate flow
sensors again.
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Before calibration, perform leak test of the breathing system in mechanical
ventilation mode first and make sure that the test is passed.
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During calibration, make sure that the drive gas pressure is kept above 0.3 MPa.
Failure to do so may lead to calibration failure.
This calibration is only intended for the flow sensors in the breathing circuit. The inspiratory
flow sensor and expiratory flow sensor in the breathing system are calibrated through the
built-in flow measurement reference.
After the inspiratory flow sensor and expiratory flow sensor have been used for several
months, for example, three months after calibration, great deviations (more than 10%
compared with the setting value) may occur to tidal volume measurement due to sensor
ageing or environmental factors. Or, the user replaces flow sensors. In this case, you need to
re-calibrate flow sensors. For details about user flow calibration, refer to the corresponding
section in the Operator’s Manual.
NOTE
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If measurement deviations are not corrected after multiple flow sensor
calibrations, the user is recommended to replace the flow sensor and then perform
calibration. If the problem persists, factory maintenance is necessary. After the
problem is fixed, perform calibration and system test.