Looks of confusion and even a smirk are the typical response I get when I tell an Engineer or customer that Phoenix Controls does not need to measure airflow. Next come the questions. Why not? How do you know what the airflow through the valve is? Why do other manufacturer’s measure airflow?
Phoenix Controls doesn’t measure airflow for several reasons:download Spider-Man: Homecoming movie now
- Speed of Response
Typical airflow measurement makes all of these things more difficult. If you were to look into how airflow is measured, you would see that it isn’t actually measured at all. Velocity pressure is what is measured and then the airflow is estimated by translating that velocity measurement via transducers. So rather than try and estimate an airflow, Phoenix Controls meters the airflow.
It all comes down to the highly accurate and extremely stable venturi air valve that Phoenix Controls uses. By placing an obstruction (a cone in this case) inside the venturi valve, the flow through the valve can be varied. The obstruction (cone) is attached to a crank arm. The crank arm moves the cone (which is attached to a shaft). When the crank arm is moved against the airflow direction, the cone begins to close off the venturi and the amount of airflow that can pass through the valve is reduced. When the crank arm is moved in the opposite direction, more air can pass through the venturi.
Due to the accuracy and repeatability of changing airflow in this way, during the factory calibration of each valve, the crank arm can be moved to any position, the flow checked, position marked, and then later returned to that same position to get the exact same airflow. Every single valve is factory calibrated for flow versus shaft position. So if the shaft position is known, the flow is also known. The flow through the Phoenix Controls air valve is accurate to within +/- 5% of any set point. This is far more accurate than any flow measurement device and is also much faster and more stable.
For more information on the Phoenix Controls venturi valve, contact one of our salesmen.