Material pairings for ATEX, speed regulations & other voltage supplies

Material pairing for ATEX

In view of possible friction, which can be expected due to malfunctions (or even rare malfunctions), potential areas of contact between rotating elements and fixed components are manufactured from materials in which the risk of ignition through friction and friction-impact sparks, hot spots of hot surfaces is minimised.

Almeco can build its fans with the following combinations:

Impeller (blades)

Fan house

Remarks

For IIA & IIB

Cast aluminium

Naval brass

Brass is put as a lining inside the steel house

Plastic

Naval brass

Brass is put as a lining inside the steel house

Plastic

Steel or cast iron

 

Plastic

Stainless steel

Only austenitic StSt

For hydrogen (IIC)

Plastic

Steel

 

Cast aluminium

Naval brass

Brass is put as a lining inside the steel house

Speed regulation

Almeco ATEX-fans can be regulated in speed by a frequency invertor. This regulation however has its conditions and limits:

  • Almeco must be informed about the speed control at the moment of order
  • In all cases temperature control of the windings (PTC) must be integrated in the circuit
  • In some cases a combination of motor and drive of the same make are obliged
  • Speed regulation of increased safety motors EExe is very complicated and therefor not recommended
  • Maximum speeds are to be defined to ensure motorpower and maximum impeller speed is not exceeded
  • Nominal motor torque (and thus power) is lower

Almeco does not support any other method of regulation for its ATEX fans. Especially regulation by throttling is out of the question.

Other voltage supplies

ATEX fans with other supplies (440 V - 60 Hz, 480 V - 60 Hz, 400 V - 60 Hz, ...) can be supplied. This is however very often accompanied with a longer lead time.

  • UL-listed Ex motors can be supplied. The American system (classes and divisions and groups) however does not overlap with the European system in an obvious way (groups and categories). Consequently Almeco can not write its standard CE declaration of conformity.
  • US "spark resistant construction", AMCA 99-0401-086 is up to now not supported by our ATEX fans
  • In some cases ATEX fans are accepted in the US
  • In most cases ATEX fans are accepted in the Middle East