Operation Mode - Wohler CFM 600 Bedienungsanleitung

Configuration and function
4.4

Operation Mode

With the Wöhler CFM 600, airflows from10 – 850 m /h can be accurately measured.
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While measuring the device will recognize automatically if it measures supply or extract
air. It measures the volume flow with the zero pressure method, which guarantees a high
accuracy. This method compensates automatically the pressure built up by the inherent
resistance of the device compared the atmospheric pressure. For the pressure compen-
sation an internal ventilator is necessary, which is controlled by a differential pressure
sensor. At the beginning of the measurement the Wöhler CFM 600 starts the ventilator
and adjusts the rotational speed so that the pressure at the air outlet falls to 0.0 Pa. This
way, the pressure caused by the air flow of the outlet is compensated by the air flow
generated by the ventilator. Another sensor measures the volume flow, which is dis-
played in the display as measured value m 3 /h (optional cfm or l/S).
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