KTR introducing magnetic coupling MINEX® -S with a new containment shroud material

For sizes SA 75/10 to SE165/24 of the MINEX®-S series KTR now offers containment shrouds made of the nylon material PEEK. Up to now the stand-ard types of this coupling have only been available with containment shrouds made of metallic or ceramic materials. Subject to their resistance to high pressures and temperatures, stainless steel or Hastelloy cover a wide appli-cation range on pumps or agitators.

For applications in the chemical industry it is a considerable benefit that the couplings are hermetically sealed so that unintentional chemical reactions, for example caused by penetration of oxygen, are prevented. Anyway, the disadvantage of metallic containment shrouds in rotating magnetic fields is the generation of eddy current losses. In order to avoid such losses completely, ceramics and newly the high-performance polymer PEEK have proven their worth. In case of using these materials, the selection torque can be reduced by 10 to 15 per cent, since the eddy current losses no longer have to be considered with the coupling selection.

PEEK and ceramics are ideally suitable for dry-running applications, since the heat being generated by metallic containment shrouds as a result of eddy current losses cannot be dissipated. For those reasons containment shrouds made of ceramics and PEEK are specifically suitable for fan drives, vacuum pumps or compressors. These applications do not provide for any or only provide for minor options of cooling and different from metallic types, the containment shrouds made of ceramics or PEEK do not generate any unintentional heat. Apart from that MINEX®-S coupling systems are used on such conveyor pumps on which a cooling circuit cannot be realized at all or can only be realized with much effort due to the medium to be pumped. Finally foaming plants for polyurethane should be mentioned which need to be hermetically sealed in order to avoid unintentional reactions with the ambient air.

KTR has used ceramics as a material for containment shrouds for a longer while already. Now PEEK is the latest material which is used. Apart from the well-known benefits like resistance to high temperatures, resistance to chemicals and hydrolysis or wear it is much easier to process PEEK than ceramics which has a much higher susceptibility to fracture. Due to a share of reinforcing glass fibres it is possible to use MINEX® couplings by KTR with a containment shroud made of PEEK each depending on the size for rated pressures up to 16 bar with permissible temperatures up to 130 °C. Containment shrouds made of PEEK are available for the sizes MINEX® -SA 75/10 (10 Nm) up to size SE 165/24 (390 Nm).