Pressure gauge classification - Huaqiang Electronic Network

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Classification

Pressure gauges can be categorized based on their measurement accuracy. They are divided into precision pressure gauges and general-purpose pressure gauges. Precision pressure gauges typically have accuracies of 0.1, 0.16, 0.25, and 0.4, while general-purpose ones range from 1.0, 1.6, 2.5, to 4.0. These classifications help users choose the right gauge depending on the required level of precision.

Based on the measurement standard, pressure gauges differ in the reference point they use for indication. There are general pressure gauges, which measure relative to atmospheric pressure; absolute pressure gauges, which measure relative to a perfect vacuum; and differential pressure gauges, which measure the difference between two pressures.

According to the measuring range, pressure gauges are classified as vacuum gauges, pressure-vacuum gauges, micro-pressure gauges, low-pressure gauges, medium-pressure gauges, and high-pressure gauges. Vacuum gauges measure pressures below atmospheric, while micro-pressure gauges are used for very low pressures (under 60,000 Pa). High-pressure gauges are designed for extreme conditions, often up to several hundred megapascals.

Based on display type, pressure gauges can be either analog (pointer-type) or digital. Analog gauges provide a visual reading through a moving needle, while digital models offer precise numerical readings on an LCD screen.

Functionally, pressure gauges can be divided into local indicating types and signal-controlled ones. Local indicators show the pressure directly on the device, while signal-controlled gauges can send data to remote monitoring systems or control mechanisms.

Pressure gauges can also be categorized based on the characteristics of the measured medium:

1. General pressure gauges: Used for non-corrosive liquids, gases, or steam that do not affect copper or copper alloys.

2. Corrosion-resistant pressure gauges: Designed for corrosive environments, such as stainless steel or diaphragm types.

3. Explosion-proof pressure gauges: Suitable for hazardous areas with explosive mixtures, like in chemical or oil industries.

4. Special pressure gauges: Customized for specific applications or media.

Based on usage, pressure gauges come in many forms, including ordinary, ammonia, oxygen, electric contact, remote, vibration-resistant, and digital types. Some even feature dual needles or inspection pointers for enhanced functionality.

Working Principle

The working principle of a pressure gauge relies on the elastic deformation of sensitive components like Bourdon tubes, bellows, or diaphragms. When pressure is applied, these components deform, and this deformation is transferred via a mechanical linkage system to a pointer, which then moves across the dial to indicate the measured pressure.

Common Industrial Pressure Gauge – Bellows Pressure Gauge

Bellows pressure gauges, also known as micro-pressure gauges, are ideal for measuring low or negative pressures in non-explosive, non-corrosive environments. They are commonly used in boiler ventilation systems, gas pipelines, and combustion devices to monitor small pressure variations in non-corrosive media.

How it works: The pressure of the medium enters the bellows, causing it to expand or contract. This movement is transferred through a linkage mechanism, rotating a gear that drives the pointer on the dial, displaying the pressure value accurately.

Applications: Bellows pressure gauges are widely used in industrial settings where precise measurement of low-pressure or vacuum conditions is required, especially in systems involving non-corrosive and non-explosive substances.