Bonfiglioli C Series ATEX Explosion proof Reducer Selection

Bonfiglioli C Series ATEX Explosion proof Diagonal Gear Reducer: Selection and Compliance Guidelines for Hazardous Area Applications

In industries such as petrochemicals, pharmaceuticals, grain processing, and spraying, combustible gases, vapors, or dust are inevitably present in the production environment. All mechanical equipment used in these hazardous areas, including reducers in the transmission system, must meet strict explosion-proof certification requirements. Bonfiglioli's C Series helical gear reducer ATEX version is a compliant transmission solution designed to meet such harsh working conditions. This article will systematically sort out the selection and application points of C Series explosion-proof reducers from the ATEX directive framework, equipment classification, selection calculation methods to installation restrictions, helping you benchmark compliance in complex projects.

ATEX Explosion proof System Fundamentals: Understanding Directive and Area Classification

The core essence of ATEX 2014/34/EU directive

The ATEX (ATmosph è res EXPLosables) Directive 2014/34/EU is a mandatory regulation developed by the European Union for equipment used in potentially explosive environments. On page 6 of the manual, it is explicitly stated that this directive for the first time includes mechanical, hydraulic, and pneumatic equipment in its regulatory scope, not just electrical equipment as before. For mechanical engineers, this means that pure mechanical products such as gearboxes also need to obtain ATEX certification in order to enter explosion-proof areas in Europe.

This instruction defines four conditions for an explosive atmosphere:

Presence of flammable substances (gas, vapor, mist, or dust)

Mixing with air

Under atmospheric conditions

After ignition, combustion will spread throughout the entire unburned mixture

2. Zones and Categories of Equipment

The manual clearly defines the division logic of hazardous areas on pages 6-7, which is the primary basis for selection:

Regional gas/vapor (G) dust (D) formation frequency corresponds to equipment category

0/20 Continuous or long-term permanent danger M1/1

1/21 Potential hazards occasionally occur during normal operation 2

2/22 Short term occurrence of minimum danger under abnormal operation 3

The Bonfiglioli C Series ATEX gearbox covers the following areas:

Zone 1&2 (Gas) → Equipment Categories 2G and 3G

Zone 21&22 (Dust) → Equipment Categories 2D and 3D

The table on page 7 of the manual further specifies that the explosion-proof protection types of the C Series explosion-proof reducer are Ex h Gb (gas) and Ex h Db (dust), where "h" represents "non electrical equipment (non electrical) protection type".

3. Temperature Class

For gas environments, ATEX certification also requires the indication of temperature class (T-Class), which means ensuring that the highest surface temperature of the equipment is below the self ignition temperature of the surrounding combustible gases/vapors.

T3 (maximum surface temperature ≤ 200 ℃): Suitable for most common industrial gases

T4 (maximum surface temperature ≤ 135 ℃): Higher level, suitable for occasions requiring lower temperature thresholds

The option code on page 14 of the manual shows:

2G3G-T3: Suitable for Zone 1/2 gas environment, temperature level T3 (200 ℃)

2G3G-T4: Suitable for Zone 1/2 gas environment, temperature level T4 (135 ℃)

2D3D-160: Dust environment, surface temperature<160 ℃

2D3D-130: Dust environment, surface temperature<130 ℃

Selection prompt: The temperature level must be selected higher than (i.e. stricter) the self ignition temperature of combustible substances present in the environment. For example, a hydrogen environment requires T1, while carbon disulfide requires T6.

Special structural features of C Series ATEX gearbox

Compared with standard industrial reducers, the ATEX certified C Series has significant differences in materials and structure (page 12 of the manual):

Fluoroelastomer (FKM) sealing ring: equipped with Fluoroelastomer (fluororubber) sealing components, it has high temperature resistance, oil resistance, and chemical resistance characteristics, ensuring that the sealing integrity can be maintained even under high temperature conditions.

Output shaft double seal rings: The manual emphasizes "Double seal rings on the output shaft" - this is to form a redundant sealing barrier at the shaft end, reducing the risk of dust or gas entering the reducer interior along the shaft.

Plastic free components: completely eliminate the risk of static electricity accumulation - plastic components may generate static electricity in friction or airflow, becoming potential ignition sources.

Special nameplate information: The nameplate clearly indicates the product category (such as II 2G) and protection type (Ex h Gb) for on-site inspection and compliance audit.

Pre oiling in the factory: Add long-lasting synthetic lubricating oil according to the installation location specified in the order, and seal it with a blind plug for transportation. The user needs to replace it with a breathable plug on site.