[Q&A Question 047] 2016.06.06
Thread Content
【Q&A Question 047】June 6, 2016: If the orifice plate of an orifice flow meter is installed in the reverse direction, how will its readings change? Why? The answer key will be available after responding; scoring is based on addressing the key points. Due to changes in the structure before and after the flow meter, the fluid velocity at the point downstream of the flow meter decreases, which in turn reduces the differential pressure; as a result, the measured flow rate is lower.
Orifice plate flow meters operate on the principle of pressure difference; when installed in reverse, the measured pressure difference is lower than that obtained when the orifice plate is installed correctly, resulting in a lower reading on the flow meter.
The display is too low, and even negative values appear. Because its operating pressure difference changes
The pressure difference before and after the orifice plate increases, resulting in a higher reading
A orifice flow meter determines the flow rate through the orifice by calculating the pressure difference before and after the orifice. When installing the orifice plate, the sharp-angle end must face the direction of the flow of the medium, while the obtuse-angle end should face downstream; it must not be installed in reverse. If installed in reverse, according to its working principle, the pressure difference before and after the orifice plate will change from positive to negative. The measured value then becomes negative as well.
If the orifice plate is installed in the wrong direction, the pressure difference decreases, and its reading will drop as well.