SummerAire SHRV2500DD, Инструкция по установке и руководство пользователя

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Inser t the Pitot Tube into the duct, pointing the tip into the airflow.
More precise readings can be made by taking a number of readings through a
cross section of the duct. The readings should be taken at the centers of equal
areas in the duct.
This procedure is outlined in the instructions accompanying the Pitot Tube.
This method is also described in the ASRAE Handbook of Fundamentals,
chapter on measurements and instruments.
Determine which duct has the highest airflow ( highest reading on the gauge ).
Then damper that airflow back to match the lower reading from the other duct.
The airflows should now be balanced.
Actual airflow can be determined from the gauge reading. The value read on
the gauge is called the velocity pressure. The Pitot Tube comes with a chart that
will give the airflow velocity based on the velocity pressure indicated by the
gauge. This velocity will be in either feet per minute or meters per second.
To determine the actual airflow, the velocity is multiplied by the cross sectional
area of the duct being measured.
Example:
• This is an example for determining the airflow in a 6” duct
• The Pitot Tube reading was 0.025” W.C.
• From this chart, this is 640 f.p.m.
• The 6” duct has a cross sectional area
= ( 3.14X { 6”/12 } 2 ) /4 = 0.2 square ft.
• The airflow is then 640 ft / min. X 0.2 square ft. = 128 cfm
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2500DD-Install-ENG 1/17/06 5:56 PM Page 18