4VORTEK Doc.# VT5 OM 050499, Rel. 2.1
1.0 OPERATION
1.1 General Description
The Tek-Air VorTek
tm
airflow measurement system consists of one or more duct
insertion probes and an electronic transmitter. The VorTek measurement system
is capable of measuring airflow volume in ducts of all sizes and shapes, as well
as fan inlet bells.
VorTek insertion probes have multiple velocity sensors located along their length.
Each sensor measures airflow velocity using a unique, patented (4,770,035)
application of the digital velocity sensing technique using the principles of vortex
shedding.
Vortex shedding is the generation of eddy currents created by an obstruction in
an air stream. Airflow through each VorTek sensor creates a succession of eddy
currents which are then sensed as pressure pulses. The frequency at which
these pulses are generated, is directly proportional to the velocity of airflow
around the sensor.
In large ducts, the profile of the air velocity across a duct is often uneven due to
the bends and transitions in the ductwork. In-line devices such as dampers,
elbows, and transitions also create disturbances in the flow profile. To compen-
sate for these varying velocity profiles, multiple VorTek sensors are utilized within
a duct. The frequency outputs of individual sensors are averaged to obtain the
average duct velocity.
The VorTek transmitter totalizes the frequency signals from the individual sensors
to perform true velocity averaging. From this average, an electronic signal (4-
20mA) is generated for direct input to a customer’s control system.
The VorTek transmitter provides several beneficial features to the user, including
adjustable damping, on-line zero check, on-line calibration, sensor diagnostics,
and optional digital indication. This manual will cover the operation, installation,
startup, and calibration of the VorTek probes and transmitter.
Chapter 1 Operation
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