# An inclined manometer is a useful device for measuring small pressure differences. The formula given in Section

## Question:

An inclined manometer is a useful device for measuring small pressure differences.

The formula given in Section 3.4 for the pressure difference in terms of the liquid-level difference h remains valid, but while h would be small and difficult to read for a small pressure drop if the manometer were vertical, L can be made quite large for the same pressure drop by making the angle of the inclination, θ, small.

(a) Derive a formula for h in terms of L and θ.

(b) Suppose the manometer fluid is water, the process fluid is a gas, the inclination of the manometer is θ = 15°, and a reading L = 8.7 cm is obtained. What is the pressure difference between points 1 and 2 ?

(c) The formula you derived in Part (a) would not work if the process fluid were a liquid instead of a gas. Give one definite reason and another possible reason.

**Formula in section 3.4 **

P_{1} + ρ_{1}gd_{1} = P_{2} + ρ_{2}gd_{2} + ρfgh

P_{1} - P_{2} = (ρ_{f }- ρ)gh

## Step by Step Answer:

**Related Book For**

## Elementary Principles of Chemical Processes

**ISBN:** 978-1119498759

4th edition

**Authors:** Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard