Question

The inverted U-tube is used to measure the pressure difference between two points A and B in an inclined pipeline through which water flows. The differenceof level h=0.4m ; X=0.2; and Y=0.3m. Calculate the pressure difference between point B and A if the top of the manometer is filled with:

i) Air
ii) paraffin of relative density of 0.75

Answer 1

i) 0.610 m or 610 mm

ii) 0.4 m or 400 mm

Step-by-step explanation:

The pressure difference between the pipes is

a) Air

Pa + πha +Ha = Pb + πhb +Hb

Pa - Pb = π(hb-ha) + Hb-Ha

Relative density of air = 1.2754 kg /m3

Pa - Pb = 1.2754 * 0.4 + (0.3-0.2) = 0.610 m or 610 mm

b) paraffin of relative density of 0.75

Pa - Pb = π(hb-ha) + Hb-Ha

Pa - Pb = 0.75 * 0.4 + (0.3-0.2) = 0.4 m or 400 mm