You are given an open-ended mercury manometer and asked to determine the pressure in a pipleline that supplies feed gas to a reactor. However, when you connect the manometer to the pipeline, you noticed that the calibration markings in the leg that connects to the pipeline are faded and no readable. You need to improvise.
a) With the manometer still connected, you turn off the gas flow and use a bourdon gauge to measure the pressure in the pipeline at several positions. Would you expect any difference between the gauge readings? Briefly justify your answer.
b) With no gas flowing, the bourdon gauge reading is 6.2 psi and the mercury level in the open leg is 800 mm above the base of the manometer. What should be the corresponding height of mercury in the manometer leg connected to the pipeline?
c) Now you turn back the gas flow and observe that the manometer level in the open leg increased by 30 mm. What is the gauge pressure in the gas pipeline?