9
Chapter 3
PRINCIPLE
Firstly, testee deep inspires, then seals the lips around the mouthpiece and blasts all air out as forcefully as possi-
ble, the exhalant gas transforms to rotary airflow by turbine, then makes the blade rotate. The reception part of the
infrared pair diodes (one is for infrared emission, the other is reception) towards to the blade is used for receiving
the infrared ray, when the blade rotates, the received ray strength of the reception diode will be different as the
difference of the blade angle, so form the various signal of same proportion in reception diode, which forms ac-
quisition signal by SCM after processing. At last, various parameters to be measured formed from the information
which were processed by the microprocessor, and displayed from the screen.
Chapter 4
TECHNICAL SPECIFICATIONS
4.1 Main performance
• Forced Vital Capacity (FVC), Forced Expired Volume in one second (FEV1), the ratio of FEV1 and FVC (FEV1%),
Peak Expiratory Flow (PEF), 25% flow of the FVC (FEF25), 75% flow of the FVC (FEF75) and average flow be-
tween 25% and 75% of the FVC (FEF2575) can be measured. Besides, the testee condition can be shown by
the ratio of the measured value and the predicted value.
• Flow rate-volume chart, volume-time chart display.
• Data memory,delete, upload and review.
• Trend chart display.
• Scaling (Calibration).
• Information prompts when volume or flow goes beyond the limits.
ENGLISH