This document discusses different types of manometers used to measure pressure. It describes a simple manometer which uses two immiscible liquids in a U-tube, where the difference in liquid levels is directly proportional to the pressure difference. It also describes a well manometer, which avoids reading two limbs by connecting one limb to a well. An inclined manometer increases the sensitivity of measurement by measuring the length of liquid column movement. A two liquid manometer uses two different liquids to precisely measure small pressure differences in gases.

1. MANOMETER
PRATHAMESH KUDALKAR
13FET1011

2. MANOMETERS
 A manometer is an instrument that uses a column of liquid to
measure pressure.
 The manometer utilizes the hydrostatic (standing liquid)
balance principle wherein a pressure is measured by the height of the
liquid it will support.
 There are many types of manometers, some of which are as follows:
 Simple Manometer
 Well Type Manometer
 Inclined Manometer
 Two liquid manometer

3. SIMPLE MANOMETER
 It consists of a transparent U-tube containing the fluid A of density
p whose pressure is to be measured and an immiscible fluid B of
higher density pm.
 The limbs are connected to the two points between which the
pressure difference (P2- P1) is required.
 If P2 is greater than P1, the interface between the two liquids in limb
2 will be depressed a distance hm (say) below that in limb 1.
 The pressure at the level a — a must be the same in each of the
limbs and, therefore;
𝑷 𝟐 + 𝒛 𝒎 𝝆𝒈 = 𝑷 𝟏 + 𝒛 𝒎 − 𝒉 𝒎 𝝆𝒈 + 𝒉 𝒎 𝝆 𝒎 𝒈
∆𝑷 = 𝑷 𝟐 − 𝑷 𝟏 = 𝒉 𝒎 𝝆 𝒎 − 𝝆 𝒈
 If fluid A is a gas, ∆𝑷 = 𝒉 𝒎 𝝆 𝒎 𝒈

4. SIMPLE MANOMETER

5. WELL TYPE MANOMETER
 In order to avoid the inconvenience of having to read two limbs,
the well-type manometer can be used.
 If Aw and Ac are the cross-sectional areas of the well and the
column and hm is the increase in the level of the column and hw
the decrease in the level of the well, then;
∆𝑷 = 𝑷 𝟐 − 𝑷 𝟏 = 𝒉 𝒎 𝝆𝒈(𝟏 +
𝑨𝒄
𝑨𝒘
)

6. WELL TYPE MANOMETER

7. INCLINED MANOMETER
 The inclined manometer enables the sensitivity of the
manometers described previously to be increased by
measuring the length of the column of liquid.
 If 𝜽 is the angle of inclination of the manometer and L is
the movement of the column of liquid along the limb,
then;
𝑳 =
𝒉𝒎
𝒔𝒊𝒏𝜽

8. TWO LIQUID MANOMETER
 Small differences in pressure in gases are often measured with two liquid
manometer.
 It consists of reservoir at the top of each limb of a sufficiently large
cross-section for the liquid level to remain approximately the same on
each side of manometer.
 ∆𝑷 = 𝑷 𝟐 − 𝑷 𝟏 = 𝒉 𝒎 𝝆 𝒎𝟏 − 𝝆 𝒎𝟐 𝒈
 The sensitivity of the instrument is very high if the densities of the two
liquids are nearly the same.
 Liquids used: 1. Paraffin Oil and Industrial Alcohol
2. Benzyl Alcohol and Calcium Chloride

9. THANKS!