다음 내용은 "Controling Positive Displacement Pumps" Hydrocarbon Processing 1996/05에 실린 내용 일부를 발췌한 것입니다.

 

Flow control measurements have similar problems to pressure measurements. An additional problem
arises in the case of an orifice plate or similar head type measuring system. Since the dP varies with the square of flow rate and it is the dP that is averaged, the resulting signal is not the average of the flow rate. Rather it is the square root of the average of the square of the flow rate. (Electrical engineers recognize this as the RMS -- root mean square.) As long as the shape of the pressure signal, over time, does not change, flow will be proportional to, but not equal to, root D P. The more cylinders in the pump, the smoother the waveform will be and the closer the measured to the actual reading. Discharge pulsation dampeners also help considerably. The measured flow on "ideal" (undamped, pure sinusoidal flow waveform) simplex and duplex pumps is 11% higher than the actual flow. An "ideal" triplex pump yields a measurement that is 1% high.

 

이 중에서 마지막 문장, Simplex/Duplex는 측정치가 실제값보다 11% 높게 나오는데, Triplex는 1% 높게 나온다고 되어 있는데, 잘 이해가 가지 않는 군요...

 

고수분들의 설명 부탁드립니다.