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How does a manometer work?
Written by Nick Groenewoud | Last update: 06-11-2020
A manometer is a measuring instrument that measures the pressure of a fluid or gas in a confined space, for example in a boiler. A manometer indicates the pressure relative to the atmospheric pressure. But how does a manometer work exactly? How to choose the right manometer for your situation? And how does one subsequently take it into use? In this article our specialists explain.
How does a manometer work?
The functioning of a manometer is as follows. The meter contains a metal cylinder. When measuring a gas or fluid, the springy cylinder of the meter is pressed. Subsequently, the cylinder is deformed, which is converted to the meter, allowing you to read the result.
How does one choose a manometer?
The choice for a manometer depends on a number of factors:
- The amount of pressure (Bar) that the manometer must be able to measure. Please note: the pressure to be measured should not be higher than 2/3 of the manometer's scale, so that the meter can absorb possible peak pressure.
- For which type of fluid or gas you want to measure the pressure. Not all manometers are suitable for any fluid or gas. This is dependent on the aggressiveness of substances. A manometer may consist of phosphor bronze, which is not resistant to aggressive gases and fluids. Do you want to measure the pressure of aggressive substances? Then opt for a resistant material like rustproof steel.
- The ambient temperature and the temperature of the fluid or gas to be measured.
Manometer with glycerin
A manometer can also contain a liquid – by the name of glycerin. These manometers with glycerin are intended for measurements during which huge pressure peaks, vibrations or shocks may occur. The liquid serves to ensure that this pressure is absorbed in the pressure meter. The glycerin prevents wear, due to its damping effect.
Mounting a manometer
In order to prevent leakage, you must adequately assemble a manometer. During assembly bear in mind the following points:
- Place the manometer such that it is free from vibrations. Strong vibrations may cause the manometer to show incorrect values and may cause damage to the measuring instrument
- Also make sure that the manometer is not exposed to (> 60°C) too high temperatures.
- Manometers are calibrated in vertical position. Therefore always position the manometer vertically. If this is impossible, then have it calibrated in the desired position to prevent measuring errors.
- During (dis)assembly never rotate the casing.