User's Manual
Chapter 1 - Getting started - 21
Flowmeter
The system uses a bi-directional digital turbine. It opposes a very low resistance to flow
(<0,7 cmH
2
O/l/s to 12 l/s). The air passing through the helical conveyors, takes a spiral
motion which causes the rotation of the turbine rotor. The rolling blade interrupts the
infrared light beamed by the three diodes of the optoelectronic reader. Every
interruption represents 1/6 turn of the rotor, this allows to measure the number of turn in
the time.
Gas analysers
The O
2
and CO
2
analysers are temperature-controlled and the internal pressure and
expired flow are monitored for an higher reliability if the measurements.
The K4 b² uses Nafion Permapure ® which is a semipermeable capillary tube capable of
removing the humidity in excess without altering the gas concentrations..
The analysers calibration is automatic and shows both graphically and numerically the
flow and concentration signals and the accuracy of the baseline/gain.
PC Software
The PC software, running on Windows™, allows the user to manage data stored in the
Portable Unit or transmitted to PC. Here following a list of the main features available:
• Test data management.
• Viewing data in table and graphic form
• Automatic and manual detection of anaerobic threshold (modified V-slope
method).
• On-line data presentation during tests.
• Advanced data elaboration (filtering, smoothing, built in spread-sheet features).
• O
2
Kinetics (O
2
deficit, O
2
debt and time constant in both rising and falling edge of
a constant load exercise test).
• Flow-Volume loops during the test and overlapped on the rest FVC.
• Real time display of the O
2
and CO
2
waveforms during the test.
• Control of any ergometer provided with a RS232 interface.
• Custom fittings (linear and exponential).
• Spirometry (FVC, VC, IVC, MVV).
• File exporting in three different formats (Lotus 123™, Excel™, ASCII).
• Automatic detection of the "Steady State".
• Adding parameters and predicted equations trough the "Formula Editor" tool-kit.
• DDE with Microsoft Excel.
• Customizing software environments (colours, printed parameters...).
• Help on line.