Coversion of Elastic Couplings

Simple Conversion from Elastic Couplings to Gear-Couplings (August 2021).

Often used in the Steel- and Port-Industry: torsionally elastic claw couplings. Despite beeing technically not necessarily required, those coupling types are still popular.

If there would not be the matter with the usual high wear rate of the intermediate elastic (“spider”) ring…

This was always an annoiance of a German steelmill – but converting the elastic coupling to a Gear Coupling seemed so far to laborious. Replacing the disc, the hubs and the coupling itself and probably moving the motor and re-align it – just difficult in terms of costs, working hours and downtime of the equipment.

So the customer decided to go for the MALMEDIE^® “S-NX”, a conversion kit with the same dimensions as the middle part (claw rings) of the elastic coupling. The conversion was done in shortest time, the existing hubs and the brake disc were re-used again. And now, a Gear Coupling is in operation, which is fully encapsulated and filled by MALMEDIE^® with a longlife grease. For the next approx. 15000 operating hours, no maintenance or replacement of parts will be required.

12.100.000 Nm – new record!

The biggest ever build MALMEDIE^® Safety Coupling was installed and commissioned in August 2015.

With an astonishing shut-off torque of 12.100.000 Nm, the Safety Coupling protects a test bench for wind turbines against overloads in a safe and reliable way.

At a diameter of 2.5 meters, 21 Safety-Elements type “ASE40” are installed. Additionally, the coupling has provisions to add another 3 Safety-Elements, increasing the shut-off torque to even 14.000.000 Nm.
Single Safety-Elements can be also de-activated with a special tool, so that the coupling can be operated also with less Nos. of Safety-Elements. That results in variable shut-off torques between 1.728.500 Nm and 14.000.000 Nm.

As usual with all MALMEDIE Safety Couplings, the Safety-Elements can be re-engaged after a coupling trip simply and fast with a plastic hammer.

The test bench can test complete assembled machinery houses of wind turbines of the 5-10 MW class – which is quite new, because so far single component test of wind turbines have been the standard in that industry.

Downtime reduced from hours to minutes

Using a Torque-Tube (Shear-Tube) as an overload protection at the main drives of a roughing mill in the USA was, decades ago, certainly “state of the art”

– but from today´s point of view, the replacement of the broken Torque-Tube after an overload event means a considerable long downtime. Together with the customer, MALMEDIE^® developed a solution with a Safety Coupling to replace the existing Torque-Tube. Due to the same mounting dimensions, it was a 1:1 replacement, i.e. nothing needed to be modified at site at all. Now, after an overload event, no new parts need to be fitted and the recommissioning time is reduced from hours to minutes only.

30 years of operation – no problem!

Topic: Spares

After 30 years continuous operation of a MALMEDIE^® Gear Coupling in a vertical roughing mill in Belgium, some parts needed replacement for the first time due to wear. Even after such a long time it´s not a problem at all for MALMEDIE^® to supply single spare parts accordingly. A smart design, the use of high-quality materials and a good maintenance is the guarantee for a long service life.

Optimized Gear Joint Spindles

Sometimes customer requirements are a real challenge – like in case of Gear Joint Spindles for a hot rolling mill in Germany.

The so far used products of a competitor were showing after only a few months of operation cracks and heavy wear. But the operating conditions have been also extreme in terms of high torques at small diameters. Together with the customer and with the aid of FEM design / simulation, MALMEDIE^® developed and installed an optimized version – at full customer satisfaction.