Custom-made dry-running seals for ATEX applications

Paul Boughton

The ATEX Directive94/9/ECseeks to improve process equipment safety by defining standards for machinery in potentially-explosive environments. At the same timeATEX has created new obstacles to compliancewhich chemical processors must now surmount.

One such obstacle concerns shaft sealswhere rotating shafts penetrate process machinessuch as mixersreactorsfermentersextrudersand others.

The most common seal in these applications has traditionally been a packing glandin which square-braided ‘rope’ is clamped around the shaftto create a circumferential seal. Such seals can create much frictional heatand their ATEX use is restricted by EN13463-5:2003. This has left many powder processors looking for an acceptable substitute.

Some mechanical seals claim ATEX compatibility by requiring a lubricant flush between seal faceswhich provides cooling sufficient to satisfy the ATEX protection requirements. The presence of water adjacent to the processhowevercan trouble powder processorswho prefer dry seals.

Woodex Bearing Company’s MECO division manufactures dry-running seals for ATEX applicationstailored to the individual process requirements of each piece of machinery. They can provide both compliant protection and the security of a moisture-free seal face. 

Woodex Bearing Company Inc is based in GeorgetownMEUSA.