ATEX Pump
Centrifugal, diaphragm (AODD), screw, peristaltic, and magnetic drive ATEX pumps: comparison and when each type should be used.
Pump Type Selection
ATEX certification does not determine the choice of pump type; it only certifies that the type is suitable for explosive atmospheres. Zone class, fluid properties (viscosity, abrasiveness, solids content), flow rate, and pressure requirements are the actual determinants of pump type selection. Different ATEX pump types differ distinctly from one another with respect to these parameters; correct type selection is critical for both safety and process efficiency.
Centrifugal pumps are ideal for high flow rates and low-to-medium viscosity, but careful evaluation is required for Zone 0 due to the risk of leakage through the shaft seal; magnetic drive (mag-drive) versions eliminate this problem and provide leak-free operation. Diaphragm AODD pumps, on the other hand, do not use an electrical power source and thus carry an inherent safety advantage in all ATEX zones, including Zone 0.
High-viscosity fluids highlight commonly used screw pumps in refineries and petrochemical facilities; screw pumps suitable for IIB/IIC explosion groups are indispensable equipment for this segment. Peristaltic pumps can operate across a wide ATEX range including Zone 1+21; dry-run capability and easy maintenance provided by hose replacement make this type stand out in food, pharmaceutical, and chemical industries.
Pump Types
Magnetic-drive centrifugal ATEX pumps eliminate the mechanical seal between the rotating shaft and pump housing; thereby completely eliminating fluid leakage sources. Ideal for low-to-medium viscosity (1–500 cP) and clean or lightly particulate fluids, this type operates safely in Zone 0, 1, and 2 with high flow (tens of m³/h) and medium pressure (10–16 bar) combinations. It is the primary choice in petrochemical, solvent, and fine chemical transfer.
Air-operated double-diaphragm (AODD) pumps contain no electrical components and thus present no ignition source in explosive atmospheres. They can be used in all ATEX zones including Zone 0 without additional protective measures. Viscosity range of 0–1000 cP, maximum operating pressure of 7 bar, and dry-run capability place this type in a wide range of applications in chemical, pharmaceutical, paint, and fuel transfer. Static electricity risk is also controlled with conductive/antistatic housing and grounding connection.
Eccentric screw (progressive cavity) and gear screw pumps transport high-viscosity fluids (100–100,000 cP and higher) with constant, vibration-free flow; this characteristic is indispensable in refinery and petrochemical processes for solvent transfer and crude oil conveyance. ATEX variants suitable for IIB and IIC gas groups can operate safely even in environments with extremely low ignition energy such as hydrogen or ethylene. Due to low shear force, sensitive and shear-sensitive fluids are pumped without damage.
Peristaltic (hose) pumps operate on the principle of hose compression and release; fluid contacts only the hose and does not touch the pump housing. This isolation provides a long-life ATEX solution for corrosive, abrasive, or dirty fluids. Versions suitable for Zone 1 and Zone 21 (dust) are available; full dry-run capability is provided and maintenance is completed with a single hose change. It is preferred as the hygienic ATEX option in food, pharmaceutical, and wastewater applications.
Magnetic-drive pumps guarantee leak-free transfer of toxic, corrosive, and valuable liquids due to the absence of shaft seals. In ATEX Zone 0–1, they represent the most powerful option at critical chemical transfer points in terms of both safety and environmental compliance. The coupling between the external magnet assembly and internal rotor eliminates the mechanical friction point, thereby reducing both ignition risk and maintenance frequency. In pharmaceutical and fine chemical processes where trace-leak-free operation is mandatory, magnetic-drive ATEX centrifugal has become the standard.
Comparison Table
| Pump Type | Viscosity | ATEX Zone | Dry Operation | Typical Sector |
|---|---|---|---|---|
| Centrifugal (Mag-Drive) | Low–Medium (1–500 cP) | Zone 0, 1, 2 | No | Petrochemical, Chemical, Pharmaceutical |
| Diaphragm AODD | Wide (0–1000 cP) | Zone 0, 1, 2, 20, 21, 22 | Yes | Chemical, Pharmaceutical, Paint, Fuel |
| Screw (Eccentric) | High (100–100.000+ cP) | Zone 1, 2 | Limited | Refinery, Petrochemical, Crude Oil |
| Peristaltic (Hose) | Medium–High (1–10.000 cP) | Zone 1, 21 | Yes | Food, Pharmaceutical, Wastewater |
| Gear Screw | Medium–High (50–5.000 cP) | Zone 1, 2 | No | Oil, Fuel, Chemistry |
| Centrifugal (Shaft Seal) | Low (1–100 cP) | Zone 2 | No | Water, Diluted Chemical |
Frequently Asked Questions