In the chemical production process, a considerable number of applications require instruments with explosion-proof functions to meet on-site production safety requirements. Microcyber's pressure transmitter has obtained intrinsic safety and explosion-proof certification and can be used in explosion-risk areas. Among them, the intrinsically safe pressure transmitter has obtained the intrinsically safe explosion-proof certification of Ex ia lC T4 Ga, and can work in Zone 0 with the safety barrier. This article will explain how intrinsically safe pressure transmitters are used in explosion-proof sites.

Basic concepts related to explosion protection

For different forms of explosion protection, such as intrinsic safety, explosion-proof, increased safety, etc., the following concepts are universal. For classification, please refer to "GB3836.14 Electrical Equipment for Explosive Gas Environments Part 14: Classification of Hazardous Places", "GB 3836.1" Explosive atmospheres Part 1: General requirements for equipment.

Explosive gas atmosphere: A mixture of gas or vapor flammable substances and air under atmospheric conditions.

Hazardous places: places where explosive gas environments occur or are expected to occur.

Non-hazardous location: A location where explosive gas atmospheres are not expected to occur in large quantities.

1. Classification of Explosive Substances

Explosive substances can be divided into three categories:

Category I: Coal mine gas is methane.

Category II: Other explosive gases except methane. Category II explosive mixed gases can be specifically divided into the following levels:

Category III: Explosive dusts other than coal mines.

2. Division of hazardous areas

Hazardous places are divided into three areas based on the frequency and duration of the presence of explosive gases in the environment.

3. Classification of gas temperature groups

According to the automatic ignition temperature of explosive substances, the ignition temperature of explosive substances is divided into six groups:

4. Equipment protection level

The level of protection specified for equipment based on its potential to become a source of ignition and the characteristics of the explosive gas environment.

Common protection levels are as follows:

Intrinsically safe explosion protection system

Intrinsically safe explosion protection is often marked with "ia" and "ib" in explosion-proof systems, which represent two levels. Among them, "ia" level electrical equipment is suitable for Zone 0, Zone 1 and Zone 2 hazardous areas. During normal operation, and shall not cause ignition when applying two counted faults plus a non-counted fault under the most adverse conditions. Electrical equipment of class "ib" is suitable for use in hazardous areas of Zones 1 and 2 and must not cause ignition during normal operation and when subjected to a counted fault plus a non-counted fault under the most adverse conditions. A complete example of intrinsically safe explosion-proof marking: Ex ia IIC T4 Ga. Based on the content of the previous chapter, it is easy to understand the specific meaning of it.

The intrinsically safe explosion-proof system, as the highest form of gas explosion-proof level, limits the maximum power consumption of electrical equipment when a fault occurs through the design of circuits and processes to avoid igniting flammable gases in dangerous situations. The basic components of the intrinsically safe system are as follows As shown in the figure, it includes the power supply system and related equipment installed in a safe environment, and intrinsically safe instruments installed in a hazardous environment.

Monocrystalline silicon pressure transmitter

Microcyber's pressure transmitters are currently explosion-proof and intrinsically safe, of which the intrinsically safe certification level has reached the highest level of "ia", and can be widely used in a variety of industrial sites and sites with explosion-proof requirements.

Some performance indicators are as follows:

• Supports the latest versions of HART, FF H1, PROFIBUS PA, and PROFIBUS DP protocols;

• Can pass HART, FF, PA, DP interoperability certification tests;

• Pressure types include: gauge pressure, absolute pressure, differential pressure;

• Highest accuracy: ±0.075% of full scale (20°C, range ratio 10:1);

• Long-term stability: +0.2% upper limit of range/5 years;