Zener and galvanic barriers are two types of electrical protection devices used in hazardous or explosive environments to prevent the ignition of flammable gases, vapours, or dust. These barriers are commonly employed in industrial settings such as oil refineries, chemical plants, and mining operations.

What are Zener Barriers?

A Zener barrier is an intrinsically safe device used to limit electrical energy and prevent the transfer of excess voltage or current from the non-hazardous area to the hazardous area. It employs a Zener diode, which is a special type of diode that conducts electricity in reverse bias when the voltage across it exceeds a specific value known as the Zener voltage. By utilizing the Zener effect, these barriers regulate the energy entering the hazardous area below the level that could cause ignition. Zener barriers are commonly used to protect intrinsically safe circuits and devices, such as sensors, transmitters, and switches.

What are Galvanic Barriers?

A galvanic barrier, also known as an isolator or isolation barrier, is another type of protection device used in hazardous environments. It provides electrical isolation between the hazardous area and the non-hazardous area, preventing the flow of direct current (DC) or low-frequency alternating current (AC) while allowing the transmission of signals or data. Galvanic barriers utilize transformers or optocouplers to provide the necessary isolation. These barriers are commonly employed to protect instruments, control systems, and communication interfaces from potentially hazardous electrical faults, surges, or short circuits.

What applications would you use Zener and Galvanic Barriers?

Zener and galvanic barriers are commonly used in various applications where electrical circuits and equipment need to be protected in hazardous environments. Some of the applications where these barriers are utilized include:Process Control Systems: Zener and galvanic barriers are widely used in process control systems found in industries such as oil and gas, chemical manufacturing, and pharmaceuticals. They provide protection for sensors, transmitters, and other control devices located in hazardous areas, ensuring safe and reliable operation.Industrial Automation: In industrial automation applications, Zener and galvanic barriers are employed to protect programmable logic controllers (PLCs), distributed control systems (DCS), and other automation equipment. These barriers safeguard the communication interfaces and control signals between the hazardous and non-hazardous areas.Instrumentation and Measurement: Zener and galvanic barriers are crucial for protecting measurement and instrumentation equipment used in hazardous environments. This includes devices such as pressure transmitters, temperature sensors, level indicators, and flow meters. The barriers ensure accurate data acquisition and control without posing a risk of ignition.Power Distribution: Zener and galvanic barriers play a role in hazardous area power distribution systems. They are used to isolate and protect electrical circuits that supply power to equipment located in potentially explosive atmospheres, preventing the transfer of excessive voltage or current.Communication and Networking: In hazardous environments, Zener and galvanic barriers are used to safeguard communication and networking equipment, such as fieldbus systems, Ethernet switches, and wireless devices. They protect against electrical faults and potential ignition sources that could occur during data transmission.