Explosion Protection (ATEX / IECEx) in Measurement Technology: Intrinsic Safety Sensors from Octogon

In industries such as chemical, oil and gas, mining, and also in mills and wood processing, explosive atmospheres can arise due to gases, vapors, or dusts. Electrical equipment – including the measurement technology used – must not become an ignition source in these environments under any circumstances.

Octogon develops and manufactures load pins, load cells, and special transducers that are specifically designed for use in hazardous areas in accordance with the strict directives of ATEX (2014/34/EU) and IECEx.

The Preferred Type of Protection: Intrinsic Safety (Ex i)

For force and strain sensors based on strain gauges (SGs), the type of protection Intrinsic Safety (Ex i) is the technically most elegant and safest solution.

The principle of intrinsic safety is based on the consistent limitation of electrical energy in the hazardous area. The voltage, current, and power in the sensor are kept so low that even in the event of a fault (e.g., short circuit or cable break), neither ignitable sparks nor impermissibly high surface temperatures can occur.

Depending on the required protection zone, we offer sensors in Ex ia (for Zone 0/20, intrinsically safe even with two independent faults) or Ex ib (for Zone 1/21) versions.

Overview of ATEX Zones for Our Measurement Technology

Our Ex-certified load pins and sensors can be configured for a wide range of zones, depending on the frequency and duration of the presence of an explosive atmosphere:

Design Features of Octogon EX Sensors

Explosion protection places the highest demands not only on electronics but also on mechanical design. Our Ex-load pins are characterized by the following features:

• Hermetic Sealing: The sensitive strain gauge bridge is hermetically sealed by laser or microplasma welding. With protection classes of IP68, the ingress of even the finest dusts or aggressive gases is permanently prevented.

• Housing Materials: We exclusively use high-quality, corrosion-resistant stainless steels that are resistant to aggressive chemicals, saltwater, and mechanical damage. Friction sparks (e.g., from light metals like aluminum) are constructively excluded by the choice of material.

• ATEX-compliant Cabling: Signals are routed via special PUR, PTFE, or silicone cables approved for Ex areas, which are strain-relieved and high-temperature resistant. Alternatively, approved plug connections are used.

• Antistatic Surfaces: Constructive prevention of electrostatic charges, which is critically important, especially in dust Ex-zones (Zone 20/21).

System Integration: The Interaction with Ex-Barriers

An intrinsically safe sensor (passive, $\text{mV/V}$ signal) is always only one part of the safety chain. The sensor in the Ex-area must be connected to the evaluation electronics in the safe area via an associated apparatus – an isolating switching amplifier or a Zener barrier.

Octogon not only supplies the bare load pin but also supports you in designing the entire measurement chain:

1. Hazardous Area (Ex-Zone): Octogon load pins (Ex ia or Ex ib).

2. Boundary to the Safe Area: Ex-barrier (limits energy, separates potentials).

3. Safe Area: Measuring amplifier, PLC, or display with corresponding analog or digital signals (e.g., $4\dots 20\text{ mA}$, PROFINET).

Customized Explosion Protection Standard products often reach their limits in complex systems. Octogon develops customized load pins that fit mechanically precisely into your existing construction while meeting all standard requirements for explosion protection.

Safety tolerates no compromises. Speak with our engineering team about your ATEX application – we supply the appropriate sensor with the corresponding documentation and certification.