Explosion-proof (EX) sewage pumps - safety and reliability in explosion-hazardous areas

Explosion-proof sewage pumps are devices designed to operate in atmospheres where flammable gases, vapors or dust may be present. Thanks to their reinforced structure and EX certification, they minimize the risk of ignition, ensuring continuous operation in sewage treatment plants, pumping stations, chemical, food and petrochemical industries.

Why are EX solutions necessary?

• Safety of people and the facility: the design prevents flame/sparks from entering the surroundings.
• Compliance with EX zone requirements: selection in terms of zones (e.g. 1/2 for gases, 21/22 for dust), gas groups and temperature class.
• Maintaining traffic without downtime: lower risk of safety-related failures and outages.

Key features of explosion-proof sewage pumps

• EX housing (e.g. flameproof or reinforced) limiting the effects of a possible explosion inside and preventing ignition outside.
• Anti-spark components and adequate flame gaps at critical locations in the structure.
• Mechanical seals (often double) with an oil chamber, monitored by leakage sensors.
• Thermal sensors (e.g. PTC/klixon) in the motor windings and protection against dry running.
• Corrosion-resistant materials (cast iron, stainless steel, protective coatings) for use in aggressive media.
• Plumbing for sewage — vortex/channel impellers, possibly shredders; large passage of solids.
• EX connections and cable glands with the appropriate number of conductors and cross-section, selected for the zones and ambient temperature.

Where to use EX sewage pumps?

• Sewage treatment plants and pumping stations (wells, gas emission chambers such as H₂S, methane).
• Chemical and petrochemical plants, refineries, food and paper industries.
• Washing/fermentation zones, retention tanks, places with flammable mists and vapors.

How to choose an explosion-proof sewage pump?

1. Zone classification: specify the zone type (gas/dust), its number, temperature class and gas group of the medium.
2. Hydraulic parameters: required capacity (Q), lifting (H), viscosity, density, solids content and size.
3. Working conditions: temperature and pH of the medium, duty cycle, immersion depth, switching frequency.
4. Power supply and security: most often a three-phase system 400 V; select the cross-section of the cables, EX chokes, overcurrent and residual current protection in accordance with the documentation.
5. Materials and workmanship: corrosion resistance and compatibility with the medium (e.g. stainless steel in aggressive environments).

Benefits of using EX pumps

• Higher level of security when working in atmospheres with a risk of ignition.
• Regulatory compliance and requirements for explosion-hazardous areas.
• Lower downtime costs — durable construction and condition monitoring limit unplanned stops.
• Longer service life thanks to appropriate materials, seals and thermal protection.

FAQ - frequently asked questions

What does an "explosion-proof" sewage pump mean?

It is a device with a certified EX version, which does not become a source of ignition in certain explosion hazard zones.

Can every pump work in the EX zone?

NO. The pump must have appropriate construction, EX marking and documentation confirming its ability to operate in a given zone and conditions.

Why is a three-phase system often recommended?

Three-phase Power supply allows for more power with less phase current, stable torque and higher efficiency - crucial for reliable operation in wastewater applications.

What should you pay attention to when installing?

For correct zone classification, selection of EX cables and chokes, electrical protection, proper grounding and compliance of the entire system with documentation and standards.