Dwyer AFG - Manual (Page 6)

Table 10: Uncertainty and Repeatability of Measurement
Expected uncertainty of measurement with typical system obstruc-
tions:
Note: For rectangular ducts D= Width + Height of Duct/2
On any particular installation repeatability of signal output is likely
to be better than ±5%.
When calibrated on site (See Previous Page) uncertainty of mea-
surement is likely to be better than ±5%.
MAINTENANCE
No maintenance is normally required except where a high dust
burden is likely to be encountered in the air stream. Deposits in the
pressure holes will affect calibration and it is advisable to provide
some means of access for cleaning when installing the AFG Flow
Grid. The Series AFG Flow Grid is not field serviceable and should
be returned if repair is needed (field repair should not be attempt-
ed and may void warranty). Be sure to include a brief description
of the problem plus any relevant application notes. Contact cus-
tomer service to receive a return goods authorization number
before shipping.
©Copyright 2005 Dwyer Instruments, Inc. Printed in U.S.A. 12/05 FR# R1-443394-00
DWYER INSTRUMENTS, INC.
Phone: 219/879-8000 www.dwyer-inst.com
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A. Fax: 219/872-9057 e-mail: [email protected]
±10%
10.0D
10.0D
10.0D
3.5D
3.5D
3.5D
Obstruction
Right Angle Bend
Radius Angle Bend
r=1D or less
Opposed Blade Damper
30° Bend
Tapered Contraction
Sudden Contraction
±15%
3.5D
3.5D
3.5D
2.0D
2.0D
2.0D
Straight Upstream Length
Required to Maintain
Fig. 16
Fig. 17
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AFG iom1 1/3/06 2:00 PM Page 6