Case Studies

Barcelona

Application:

Roller table in Steel plant

Problem:

Jaure spider type coupling (Jauflex) had persistent need for maintenance as the spider rubber had to be replaced every 3 months because of shock loads and the steel mill’s high temperatures.

Solution:

Offering 20x RBI4 FH LBIM to accommodate overall length + RBI8 Driving flange to accommodate roller shaft, Celsa enjoyed the benefits of our failsafe coupling and easy replacement of blocks

Outcome:

• Protection against shock loads and failsafe.

• No stops due to couplings failure.

Barcelona

Application:

Fan drives

Problem:

8x grid couplings were fitted to the fan drives and were causing failures because of premature wear of the steel discs. As a consequence, the company were spending too much money on replacements.

Solution:

Our experts proposed 4x RBI 4 and 4x RBI 8 as a failsafe coupling that would be able to absorb vibrations.

Outcome:

• Maintenance free

• Failsafe coupling.

Application:

Mining Industry Conveyor Chain

Problem:

The oil lubricated clutch was badly leaking oil and starving the sprag mechanism and bearings of lubrication.
The lip seals had failed to such an extent that constant replenishing of the oil was required to stop the clutch seizing.

Solution:

Renold supplied a sealed, and greased for life, sprag clutch SHCT2400 back stop with additional chambers to purge dust and debris away from the sealed sprag mechanism.

Outcome:

The life of the clutch was extended by 3 years before it was removed, still in working order, for inspection. It is now available as a spare for the next scheduled maintenance window.

Alicante

Application:

Tension leveller and bridles retrofit at an aluminium plant.

Problem:

Shock loads can be high, damaging gear couplings teeth and gearing on drive line. They needed shock load protection coupling.

Solution:

High Speed Side:6x RBI 4 with brake disc arrangement and low speed side: 6x RBI’s with special driving flange in EN19 material to be fitted on tollok

Outcome:

• Maintenance free

• High performance

The mill stand houses the motors and generators that transmit power to the mills which run the hot steel slabs and reduces them to billets to be transformed into steel sheet rolls. The heavy duty gear couplings used are sizes GF12 and 14HDB. They are run 24/7 to maintain continuous mill activity, making any downtime critical.

Problem:

The lifespan of the gear couplings was being significantly reduced due to the dispersal of the grease around the gearing area. The continuous high speed was causing the grease to travel away from the gearing which was therefore resulting in the coupling being starved of the necessary lubrication that is critical for metal to metal contact.

Solution:

Renold has been providing maintenance and repair services to the steel industry for over 25 years. We worked with the site team to enhance the existing design by incorporating an additional ‘floating labyrinth seal’ positioned on the inner gear hub boss. This reduced the cavity around the gearing and ensured concentrated lubrication. It also restricted the grease from filling the void between the coupling halves and being lost down the shaft keyways. We also fitted pressure release valves to avoid pressure building up in the reduced cavity.

Outcome:

The coupling life has been proven to be extended by 50% and the mill has also benefitted from reduced downtime and reduced costs associated with the wasted grease.