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When operating in a potentially explosive atmosphere it’s necessary to use a suitable pump designed and manufactured according to the ATEX directive 2014/34/EU. Here are five main things you should know when dealing with Atex Pumps:

1. Equipment used in potentially explosive atmospheres is divided into groups and categories according to the degree of protection offered. You can see and example in the table below.
   

   Table 1 – Atex groups and categories

2. Pumps for use in potentially explosive atmospheres will normally be classified under Group II, Categories 2 and 3. It is the responsibility of the end user to classify the zone and the corresponding group (dust or gas) in accordance with the EC – Directive 1992/92/EC. Once the pump manufacturer knows the Atex classification needed by the customer, it’s possible to select the right pump solution.
3. Atex pumps have a special design which prevents the formation of sparks and the ignition of explosive atmospheres that may be produced or released by equipment. They must be assembled to Explosion proof motors with the same safety measures.
4. Atex pumps for zone 1, where explosive atmosphere caused by gases, vapours, mists or air/dust mixtures are likely to occur, must be equipped with safety devices like dry running protection and thermoprobe PT 100. The dry running protection checks constantly the active power of the motor, which is the medium value of the instantaneous power absorbed by the pump, and prevents the dry-running of the pump, the closed discharge and the blocked suction. PT100, instead, is a resistance temperature detector used is used for monitoring the operating temperature of the pump.
5. Atex pumps need a certification issued by the manufacturer and shall be marked with the following information:
   

   Atex mark

• name and address of the manufacturer
• CE marking
• series type, year of construction and serial numer
• the specific marking of explosion protection followed by the symbol of the equipment group and category

The European Commission issued a guideline to facilitate the application of Atex directive 2014/34/EU which could be useful for the first approach to Atex products.

If you need to select a chemical pump, first of all you should find out some important technical data which are extremely useful for the right choice of pump: capacity/flow and head/differential pressure required, kind of liquid, temperature, viscosity, possible presence of solids in suspension and if possible also NPSHa.

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