DP Transmitter

Dear Guest,

Volumetric flow when passing through the orifice area of the flowmeter produces d/p head that is proportional to the square of the velocity of the fluid at that point. Only after the square root is extracted is the signal from the d/p transmitter proportional to volumetric flow. If you account for fluid and meter constants properly you will have a signal that is linear with flow. The square root extraction causes large errors when the flow reduces by a factor of three or more from full rated flow. You have not mentioned the d/D ratio or the size of your orifice, segmental plate, flow tube, or pitot device in your calculation. I only mention the most common flow devices, but you must account for what creates the differential pressure.

Luther M

We also encountered inaccurate reading while we did field calibration on a flow x'mtr. the reading in the x'mtr is diffrent from the calculated values. later it was corrected when we extracted the squaroot.