Novel Teflon grade helps pumps meet ATEX

Edited by the Engineeringtalk editorial team May 18, 2006

Someflu uses Teflon PFA C-980 as the material of choice for most components in its range of antistatic pumps.

Someflu, a French company specialised in the design and the manufacture of corrosion resistant centrifugal pumps, uses DuPont Teflon PFA C-980 as the material of choice for most components in its range of antistatic pumps.

The material's excellent conductivity allows the discharge of electrostatic charges, thus enabling the pumps to comply with the ATEX European Directive (94/9/EC) concerning the use of equipment in potentially explosive atmospheres.

Further benefits include the melt-processable fluoropolymer's high chemical resistance and ability to withstand high service temperatures combined with good melt-flow properties (MFR: 2.5g/10min).

Someflu, founded in 1962, produces a full range of stainless steel or plastic centrifugal pumps destined for corrosive chemical liquids that can achieve flow rates from 1 to 1500m3/h.

According to the specific characteristics of the liquid to be pumped - in terms of its concentration, temperature and viscosity - and the specific installation conditions, Someflu has traditionally used polypropylene, polyvinylidene fluoride (PVDF) or natural perfluoroalkoxy (PFA).

PFA was specifically used by Someflu for pumps handling particularly corrosive fluids and exposed to high temperatures.

It was as the company was looking to produce a range of pumps that comply with the ATEX Directive 94/9/EC, for components in explosion-proof areas, that it investigated the use Teflon PFA C-980.

Ideal for applications requiring static dissipation along with thermal or chemical resistance, the recently launched grade offers an ideal and almost unique combination of properties.

Teflon PFA C-980 is produced by a patented process from fully fluorinated perfluoroalkoxy.

For this reason, a low level of conductive filler is sufficient to achieve a volume resistivity of only 0.25ohm-m (maximum), thereby efficiently suppressing static charging.

Components with this antistatic fluoropolymer lining ensure increased safety in handling potentially explosive substances.

Moreover Teflon PFA C-980 has an increased cracking resistance and flexural fatigue strength because of its low filler content.

The material's low viscosity, while keeping the aforementioned properties with regards to conductivity and chemical resistance, can lead to higher productivity for part manufacturers.

Exploiting the over 20 years of experience in the processing of high performance plastics, Someflu and its moulding division, Aplast, were able to mould and machine very thick parts made of Teflon PFA C-980 to gain maximum benefit of the material's inherent properties.

Used in all relevant parts of its antistatic pumps that are in direct contact with the chemically-aggressive medium, Someflu has been able to produce highly reliable pumps.

"The outstanding physical and chemical properties of Teflon PFA C-980 means that our pumps can both comply with the most demanding applications, whether highly aggressive products, those at low or high temperatures or high purity products, whilst the material's electrical conductivity has seen us receive ATEX certification for our range of high-performance plastic pumps", adds Marc Legoit, ATEX Development Manager from Someflu.