VICI 230 Dynacalibrator - Manual (Page 33)


10. Rinse the fan screen and fan filter in clean water and blow dry with low-
velocity air.
11. Reinstall the fan, fan filter, fan screen brackets, and fan screen using the
four screws, lockwashers, and hex nuts.
12. Replace the top cover of the unit and return it to service according to the
procedures on page 13.
Carrier Flow Rate Verification
The carrier flow rate is maintained at a constant value through through the
use of a control device. On models with the EE option this control device is an
electronic mass flow controller (MFC), which is preset at the factory to provide
a constant 100 sccm flow through the chamber. On other systems the flow is
controlled with a differential pressure regulator which keeps a constant pressure
on a precision orifice plate. The actual flow rate is fixed, and designated by letters
at the time of manufacture. Check the certification which is included with the
system to verify the factory settings for carrier flow.
Monitoring of flow on EE models is done by reading actual flow value from the
front display. On standard models, there is a rotometer which is used only for
relative indication of the flow; however, changes in its reading can indicate the
need for flow verification. To verify the flow rate, a one liter N.I.S.T. traceable flow-
meter is recommended. After using the appropriate leak checking procedures to
determine that the calibrator has no leaks, proceed as follows:
1. Remove power from the unit.
2. Remove the top cover of the unit.
3. Close the dilution flow control valve(s) all the way (fully clockwise).
4. Plug the overflow vent securely.
5. Connect the flowmeter to the span outlet.
6. Connect main power to the unit and depress the main power switch. If the
unit does not have an internal main pump, connect a gas source to the supply
or carrier inlet.
7. Measure the flow rate to an accuracy of ±1% per the instructions in the
flowmeter manual.
8. Record the flow rate on the current Flowmeter Calibration Data sheet for the
Dynacalibrator.
Dilution Flowmeter Calibration
VICI recommends that Dynacalibrators be returned to the factory for N.I.S.T.
traceable dilution flowmeter calibrations, unless you have access to sophisticated
flow measuring equipment.
Maintenance