Q.1 What are manometers ? How are they classified ?
Differentiate between (i) Simple manometers (ii) Differential manometers.

Answer :
Manometers are self-balancing deflection type of pressure measuring instruments which give continuous rather than stepwise output. In manometers, pressure at any point in a fluid is measured by balancing the column of fluid by the column of same or another fluid. The most commonly used standard fluid in manometers is mercury. Manometers can be classified as -
(i) Simple manometers
(ii) Differential manometers.

(i) Simple Manometers - A simple manometer in its simplest form consists of a tube bent in U-shape, one end of which is connected to the gauge point and the other is open to the atmosphere. Simple manometers are used to measure pressure at a point in a fluid contained in a pipe or a vessel. Common types of simple manometers are -
(a) Piezometer
(b) U-tube manometer
(c) Single column or well type manometer (vertical and inclined).

(ii) Differential Manometers – In general, a differential manometer consists of a bent glass tube, the two ends of which are connected to each of the two gauge points between which the pressure difference is required to be measured. Differential manometers are used for measuring the pressure difference between two points in a pipe or in two different pipes. Common types of differential manometers are -
(a) U-tube differential manometer
(b) Inverted U-tube differential manometer
(c) Micromanometer.