Ametek 5000 Instrument Manual page 98

Procedure for Using Bubble-O-Meter
The Bubble-O-Meter is used to calibrate the flow rate of the gas
through the system. Proceed as follows:
1. Wet the entire inside of the Bubble-O-Meter (tube)
with a dilute liquid detergent or shampoo solution
through the top of the tube.
2. Tilt the tube sideways and turn it to wet the entire
inside surface.
3. Hold the tube upright and check that the liquid level
in the rubber bulb is slightly below the Y arm. If level
is too high, bubbles will flow without squeezing the
bulb. Pour out some of the liquid if this happens.
4. Connect the bottom Y inlet port to a gas source with
rubber or plastic tubing.
5. Measure the gas flow rate by carefully squeezing the
bulb to form a single bubble and, with a stopwatch,
time its transit time between two adjacent calibra-
tion marks.
When making precision measurements, use the gas law

equations to correct for ambient temperature and vapor
pressure, and water tension above the soap solution; be sure
NOTE
to add distilled water occasionally to compensate for evapo-
ration.

When making measurements at low flow rates with gases
like helium or hydrogen, form several films ahead of the one
NOTE
being timed to prevent gas loss by diffusion through the
film.
A-4 5000 Multi Point Moisture Analyzer
(Figure A2)

Figure A2: Bubble-O-Meter