TSI Instruments ALNOR AXD 530, Руководство пользователя

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12
Before taking the measurement, multiply the numbers in the table by
the duct diameter to get the insertion depth for the probe. (Do
not
forget to use the inside dimension of the duct if it is lined with
insulation.)
Traversing a Square Duct
Using the log-Tchebycheff method, the duct is divided into
rectangular areas, which are further adjusted in size to account for the
effect of the duct wall on airflow. A minimum of 25 points must be
measured in order to get a good average. The number of data points to
be taken along each side of the duct depends on how wide the duct is.
For duct sides shorter than 30 inches, five traversal points must be
taken. For duct sides of 30 through 36 inches, six points must be
taken. For duct sides longer than 36 inches, seven points must be
taken. Multiply the numbers in the table by the duct dimension to get
the insertion depth for the probe.
Figure 2: Location of measuring points for traversing a rectangular
duct using the log-Tchebycheff method