TSI Instruments ALNOR LOFLO BALOMETER Series, Owner'S Manual

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9
9
SECTION 9
Maintenance
Hoods
Hoods may be cleaned in cool water with a mild
detergent.
Sensing Manifold
The manifold should be checked visually before
using to be certain that the sensing holes have not
become clogged with dirt or dust particles. Do
not
immerse the manifold in water. It is recommended
that cleaning be done with extreme care with the
manifold in place. Do
not use highly compressed
air to clean the manifold tubes.
Calibration
It is recommended that your LoFlo Balometer
®
Capture Hood be returned to the factory once a
year for a calibration check. When shipping the
LoFlo Balometer
®
Capture Hood for factory
calibration, pack it carefully, and follow the
Instructions for Return in this manual.
Vent Operation
If the vent becomes difficult to operate, remove
both thumbscrews from the vent mechanism and
spray the contacting surfaces with silicone spray
lubricant. Wipe off excess and reassemble vent
mechanism.
Performance Check
If the calibration is to be checked, the best way is
to use a reference flow standard more accurate
than the LoFlo Balometer
®
Capture Hood. Flow
standards that may be used for this purpose
include orifice plates, venturis, nozzles, and
laminar flow elements. These devices require
accurate differential pressure, barometric
pressure, and temperature reading instruments to
measure either actual or standard volume rate.
If the LoFlo Balometer
®
Capture Hood is checked
against a velocity instrument such as a pitot
probe/manometer or thermo-anemometer, there
may be errors. If a velocity standard is used, the
average velocity must be obtained by taking a
traverse.* The accuracy of the traverse is
dependent on the flow uniformity, the number of
readings taken, the accuracy of the velocity
instrument, and operator expertise. This average
velocity reading must then be multiplied by the
area over which the traverse was taken.
Finally, air flow instrumentation is dependent on
environmental conditions such as temperature,
atmospheric pressure, humidity, and even
turbulence. These conditions can have very
different effects on various instrument types.
Caution must be exercised when making
comparisons.
*A traverse is a set of velocity readings taken in a
prescribed pattern which will provide an overall velocity
value when averaged together. Any of the Alnor velocity
measuring instruments can be used for this purpose.