Material improvement of 6" and 8" Stainless steel submersible pumps
Due to increased demand for drinking water certified submersible pumps, Franklin Electric introduces several changes to the 6" / 8" pump series to ensure certification by major European drinking water authorities.
All changes listed below will be effective in production starting from July 2021. The part numbers of the pumps will not change.
Materials approved for drinking water applications:
All rubber parts will be changed to drinking water approved materials. The rubber material of the O-rings and bearing bushings will be changed from NBR/HNBR to EPDM. This enables the rubber compounds to be approved for DM174, WRAS, UBA, ACS and NSF certificates.
The EPDM material has a hardness comparable to NBR/HNBR and allows a maximum working temperature of + 90 °C for all material pump variants. The material NBR with a maximum pump operating temperature of + 60 °C is still available on request.
UPPER AND INTERMEDIATE JOURNAL SLEEVE
The material of the upper journal sleeve bushings changes from ceramic-coated stainless steel (with chromium content) or Tungsten Carbide (Widia) to Aluminum Oxide. The intermediate journal sleeve is also changed from Tungsten Carbide to Aluminum Oxide. Tests in our laboratories have shown that the mechanical performance requirements of the new sleeve are guaranteed and that it is comparable to the two current options.
Alumina guarantees good thermal stability and excellent corrosion resistance, both in acid and alkaline environments. In addition, the material offers good oxidation resistance, very good hardness and excellent wear resistance.
Improved mechanical features
For the radial models, the material of the wear rings is changed from PTFE to PPS. The new type of wear ring is 100% compatible with the current diffusers. In addition, the PPS component is less affectable to temperature variations and has better dimensional tolerance than PTFE. These properties have been confirmed by laboratory tests since 2016, as this material has already been successfully integrated in other products.
Please do not hesitate to contact your Franklin Electric Sales contact for more information.