i want the equation of this question. Tranmitter range is 120 mmwc and dcs flow

i want the equation of this question.
Tranmitter range is 120 mmwc and dcs flow range is 1700 nm3/hr. if i want to change dcs range from 1700 to 2400 nm3/hr then how much dp i have to enter in transmitter

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i want the equation of this question. Tranmitter range is 120 mmwc and dcs flow range is 1700 nm3/h..

Answer / carl_ellis

Answer: 239.2 mmH2O

Present max flow rate = 1700 nm3/hr
Present max DP (at max flow rate) = 120 mm H2O

New max flow rate = 2400 nm3/hr
New max DP (at new max flow rate) = x

2400/1700 = 1.412 or an increase of 141.2% in flow rate.

The DP and the flow rate relationship is a square root relationship, but the calculation is based on normalized percentage.

X = 1.412^2*120
X = 1.993*120
X = 239.2 mmH2O

The increase in max DP from 120 to 239.2 mmH2O is an increase of
239.2/120 = 1.993 or 199.3% increase in max DP at max flow rate.

Sq root of 1.993 = 1.412 or 141.2% increase in max flow rate (2400/1700)

Carl Ellis
Measure First

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i want the equation of this question. Tranmitter range is 120 mmwc and dcs flow range is 1700 nm3/h..

Answer / alim

I think the equation is not straight forward, you need some repetition formula for calculating this.

Normally, I will use some software to do this kind of calculation such as InstruCalc. The data that you presented in the question is not enough. I am assuming that you are using the orifice in as the flow element, then you still need viscosity and specific gravity of the fluid.

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