Skip to main content

Manometer Types

Manometer Types

A manometer is a device used for measure the pressure of a fluid by balancing it with against a column of a liquid. Five different types of manometers are shown below with images.

U-Tube Manometer:

It consist a U – shaped bend whose one end is attached to the gauge point ‘A’ and other end is open to the atmosphere. It can measure both positive and negative (suction) pressures. It contains liquid of specific gravity greater than that of a liquid of which the pressure is to be measured.
U-Tube Manometer
where ‘γ’ is Specific weight, ‘P’ is Pressure at A.
Pressure at A isP = γ2h2 – γ1h1

Differential U-Tube Manometer:

A U-Tube manometric liquid heavier than the liquid for which the pressure difference is to be measured and is not immiscible with it.
Differential U tube Manometer
Pressure difference between A and B is given by equation
PA – PB = γ2h2 + γ3h3 – γ1h1

Inverted U-Tube Manometer:

Inverted U-Tube manometer consists of an inverted U – Tube containing a light liquid. This is used to measure the differences of low pressures between two points where where better accuracy is required. It generally consists of an air cock at top of manometric fluid type.
Inverted U-Tube Manometer
Pressure difference can be calculated from equation
P1 – ρ1*g*H1 – ρm*g(H2– H1) = P2 – ρ2*gH2

Micro Manometer:

Micro Manometer is is the modified form of a simple manometer whose one limb is made of larger cross sectional area. It measures very small pressure differences with high precision.
Micro Manometer
Let ‘a’ = area of the tube,
A = area of the reservoir,
h3 = Falling liquid level reservoir,
h2 = Rise of the liquid in the tube,
By conversation of mass we get A*h3 = a*h2
Equating pressure heads at datum we get
P1 = (ρm – ρ1)*gh3 + ρm*gh2 – ρ1*gh1

Inclined Manometer:

Inclined manometer is used for the measurement of small pressures and is to measure more accurately than the vertical tube type manometer. Due to inclination the distance moved by the fluid in manometer is more.
Inclined Manometer
Pressure difference between A and B is give by equation.
inclined manometer equation

Comments

Post a Comment

Popular posts from this blog

Fundamental Concepts and Terms in Vibration

Fundamental Concepts and Terms in Vibration Vibration is a mechanical phenomenon, It is a movement first in one direction and then back again in the reverse direction. e.g: the motion of a swinging pendulum, the motion of a tuning fork. Any simple vibration is described by three factors: its amplitude; its frequency and rate of oscillation. Some of the general terms you will come across while studying on vibration topic are Oscillatory motion, Simple Harmonic Motion, Periodic Motion. now we will see the above mentioned terms in brief. Oscillatory motion is described as motion that repeats itself in a regular intervals of time. for example a sine wave or cos wave or pendulum. The time taken for an oscillation to occur is often referred to as the oscillatory period. Simple Harmonic Motion: Simple Harmonic Motion is periodic motion in which the restoring force is directly proportional to the displacement. F = -k*x A simple harmonic motion of a pendulum is an example of m...
1 comment
Read more

Grashof’s Law

Grashof’s Law The Grashof’s law states that for a four-bar linkage system, the sum of the shortest and longest link of a planar quadrilateral linkage is less than or equal to the sum of the remaining two links, then the shortest link can rotate fully with respect to a neighboring link. Consider a four-bar-linkage. Denote the smallest link by S, the longest link by L and the & other two links by P and Q. If the Grashof’s Law condition is satisfied i.e S+L ≤ P+Q, then depending on whether shortest link ‘S’ is connected to the ground by one end, two ends, or no end there are 3 possible mechanisms. They are: Double crank mechanism Double-rocker mechanism  and Crank and Rocker Mechanism 1. Double crank mechanism In double crank mechanism, the shortest link ‘S’ is a ground link. Both input crank and output crank rotate at 360°. Grashof’s condition for double crank mechanism: s+l > p+ q Let:  ‘s’  = length of shortest link, ‘l’  = length...
3 comments
Read more

Gruebler’s Equation

Gruebler’s Equation Degrees of freedom for planar linkages joined with common joints can be calculated through Gruebler’s equation. Gruebler’s equation is given by the formula: where, n = total number of links in the mechanism j p  = total number of primary joints (pins or sliding joints) j h  = total number of higher-order joints (cam or gear joints) Mechanisms and structures with varying mobility for Figure (a), (b) and (c) Most linkages used in machines have a single degree of freedom. An example of single degree-of-freedom linkage is shown in figure (a). Linkages with zero or negative degrees of freedom are termed locked mechanisms. Locked mechanisms are unable to move and form a structure. A truss is a structure composed of simple links and connected with pin joints and zero degrees of freedom. An example of locked mechanism is shown in figure (b). Linkages with multiple degrees of freedom need more than one dri...
1 comment
Read more