What is Manometer
In this article, we will learn about What is Manometer and its advantage and disadvantage.
We know that pressure gauges are manometers. In which the pressure is calculated by balancing the level of the fluid in the tubes. These can be divided into the following.
a. Simple manometers b. Differential manometers
Common types of Simple manometer are:
1. Piezometer tube
2. U – tube manometer
Common types of differential manometer are:
1. U – tube differential manometer 2. Inverted U – tube differential manometers 3. Micro manometer.
Advantages of manometers:
1. Easy to design 2. Show proper pressure. 3. Calculate the location or negative pressures.
Disadvantages of manometers:
1. It takes up too much space. 2. Stress is obtained by calculations. 3. It cannot be taken elsewhere.
Applications of manometers:
1. It helps to measure low pressure ie negative pressure.
Simple manometers:
1. Piezometer tube:
It is a simple system used to calculate low pressure. The length of the pipe is a glass tube marked with vertical dimensions that open both ends so that the water in the tube does not overflow. To calculate the pressure of a fluid flowing in a pipeline, the glass tube is inserted perpendicular to the flowing pipe.
The height of the fluid entering the glass vessel is equal to the pressure of the fluid in the tube. This can be seen from the size of the engraved glass tube. If the height of the glass tube is h.
Pressure in the pipe = h mm of liquid.
Piezometer is not used for the following reasons:
1. Atmospheric pressure can withstand water of 10.33 m. When the measuring pressure exceeds atmospheric pressure, the length of the glass tube must be greater than 10.33m. Otherwise, the fluid will overflow (overflow).
2. It is difficult to make a high-end glass tube.
3. It is difficult to handle a glass tube with a high length.
2. U – tube manometer:
It is a U-shaped curved glass tube. One end of this is the pressure gauge pipe (B) and the other end is the atmosphere. Typically, the glass tube contains mercury or some other liquid. The specific gravity of this fluid must be greater than the specific gravity of the fluid to be measured.
a. For gauge pressure:
Point B must be taken to measure pressure. Its value is h m. Let us take the Datum line as A – A.
Let h1 – the datum line above the light liquid of Height
h2 – Heat of heavy liquid say mercury above the datum line
S1 – Specific gravity of the light liquid
S2 – Heavy liquid of specific gravity
The surfaces that are horizontal are equal to the pressure head. So that the pressure head above the datum line A – A is equal to both sides of the U – tube.
Pressure head above A – A in the left column = h + h1S1
Pressure head above A – A in the right column = h2S2
Equating the above, we get
h + h1S1 = h2S2
h = h1S1 – h1S1
b. For vacuum pressure:
The level of heavy liquid in the U – tube is below the vacuum compressor. Therefore
Left column = h + h1S1 + h2S2 in press A-A above the pressure head
Press column head A-A in the right column = 0
Equating the above, we get h + h1S1 + h2S2 = 0
h = – (h1S1 + h2S2)
Read Also : What is Barometer
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