Pressure Gauge & Its Types

What is a pressure gauge?

A pressure gauge is an instrument that measures the force that a fluid (liquid or gas) would exert while at rest on a unit area, such as newtons per square centimetre, and is used to define the state of a fluid (liquid or gas). The gauge pressure is the reading on a gauge that represents the difference between two pressures. The total or absolute pressure is equal to the sum of the gauge and atmospheric pressures if the lower of the two pressures is the atmospheric pressure. Now, before I dive into the article, check out Unitrade to purchase your own pressure gauges in Malaysia right now.

What is it used for?

The pressure gauge is used to monitor the intensity of fluid, gas, water, or steam in a pressure-powered machine to verify that there are no leaks or pressure variations that could compromise the system’s functioning. Pressure systems are made to work within a certain range of pressures. Any divergence from the allowed norms can have a significant impact on the system’s operation.

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Types of Pressure Gauges

Bourdon Tube Pressure Gauge

A bourdon tube pressure gauges are used to measure pressures of gas, steam, or liquid up to 1000 bar and down to -1 bar. An elastic tube is soldered or welded into a socket on one end of a Bourdon tube pressure gauge. The deflection in the tube is proportional to the applied pressure and is communicated to a rotating gear with a pointer as the pressure changes. A Bourdon pressure gauge works on the idea that when pressure is applied, a curved tube straightens; this is represented by a dial or digital display.

Diaphragm Pressure Gauge

A diaphragm pressure gauge is primarily used to monitor low-level pressure. When pressure is applied to a diaphragm pressure gauge, it becomes displaced. This type of pressure gauge operates in the same way as a Bourdon pressure gauge, except instead of a flexible tube, it uses a diaphragm to detect pressure. The difference between the applied and reference pressures is determined by the diaphragm, which is sandwiched between two flanges. It can measure gas, steam, and fluid pressures from 40 bar to -1 bar. 

Capsule Pressure Gauge

Capsule pressure gauges are used to measure the pressure of substances up to 600 mbar with an accuracy of 1.6%. These gauges are made of two thin, concentric corrugated diaphragms that are sealed securely together around their circumferences, and they are only used to monitor the pressure of gases. A hole in the centre of one of the diaphragms is what allows the medium to pass through. The diaphragms expand and compress in response to pressure. The rotating movement shown on the gauge’s face is caused by this change in form. 

Absolute Pressure Gauge

Absolute pressure gauges are used to measure the pressure that is independent of atmospheric pressure variations. A reference vacuum is coupled to the side of the measurement element that is not subject to pressure and maintains constant pressure. The media chamber is separated from the vacuum chamber by a diaphragm, which deforms into the vacuum chamber as pressure builds. Through this, a pressure value is calculated from the deformation and change.

Absolute pressure gauges, unlike other pressure gauges, are unaffected by changes in altitude, making them perfect for applications such as aeronautics, HVAC systems, and distillation processes.