VICI 340 Dynacalibrator - Manual (Page 22)

18
Verifying Operation
1. Connect a piece of tubing of the proper length to the span outlet fitting on
the rear panel, leaving the analyzer end of the tubing disconnected. Ensure
that all other tubing is properly connected.
2. Adjust the permeation chamber temperature to deliver the required rate of
permeation.
3. Gently turn the dilution flow control knob clockwise until you encounter the
stop indicating the needle valve is fully closed, then open it three turns coun-
terclockwise.
Never use excessive torque in closing a dilution stream
flowmeter needle valve. Close the valve slowly, and only as
firmly as is necessary to cause the rotameter float to come to
rest on the bottom insert in the flow tube. Excessive torque
can damage the needle valve stem and/or seat.
4. Place the mode selector switch in the ZERO position.
5. Press the main power switch and note that the indicator illuminates.
(NOTE: In units with the VAC option, first turn power on by pushing the rear
panel rocker switch up. After power is turned on at the rear panel, push the
main power switch on the front panel.)
If the unit is equipped with an internal pump, the floats in both flowmeters
will rise. If the unit does not have an internal pump, start the external supply
and note that the floats rise.
The pressure of the external gas source connected to the
supply must be at least 10 psig but no more than 30 psig.
High pressure pumps and gas cylinders are potentially very
dangerous. Extreme care must be exercised when making
or breaking connections between the Dynacalibrator and
external gas sources.
6. Adjust the dilution flow control valve until the center of the ball float in the
dilution flowmeter is at the scale reading from the Flowmeter Calibration Data
sheet for the selected dilution flow rate.
NOTE: When making a determination of the dilution flow by reading the
position of the dilution flowmeter float, the line of sight of the person mak-
ing the determination must (a) pass through the center of the spherical float,
and (b) be perpendicular to the axis of the flowmeter containing that float. All
readings should be made to the center of the float. Failing to make readings in
this manner can introduce parallax errors.
7. Check that there is gas flow out of the chamber vent, overflow vent, and
stream outlet, and that the outlets are not blocked.
8. Place the mode selector switch in the SPAN position.