Large savings for sheave/pulley driven machinesStora Enso in Sweden has focused on developing a program for preventative maintenance since 2003. Their previous maintenance manager took the first step towards large savings for all sheave/pulleys.
"We soon realised that an investment in Easy-Laser® BTA would give great savings" says Jan-Ove Westlund at the department for mechanical maintenance at Stora Fors AB. He continues:
"Since we started using the BTA to align our sheave/pulleys we can safely say that the consumption of belts and pulleys has reduced considerably. This has even meant greater machine availability. If, like we do, one has 250 sheave/pulleys, it is easy to understand what this means. In that the tool is also extremely user friendly, in principle self instructing, means that it is really utilised to its full."
They measured the energy consumption before and after alignment and received savings figures of between 5 and 20 percent. They started work on the their most important machines such as vacuum pumps, pulpers, mixers and sheave/pulley driven filters, with a focus on two main points:
Alignment using Easy-Laser® BTA for sheave/pulleys
- Make access to the pulleys easier by replacing fixed guards with guards with hatches that are easy to open for the alignment work
The savings that could be counted:
200 sheave/pulleys x € 535 / year = € 100,700 (average cost for replacement parts such as pulleys, belts and bearings)
10 % energy saving (average) = € 214,000 (200 sheave/pulleys with average 25 kW motor with 8000 operating hours and € 0.054/kWh)
Avoidance of 24 hours paper machine downtime = € 216,000
(1 Euro roughly equals 1 US Dollar)
Another company, SSAB in Borlänge, has more than 200 sheave/pulleys in its facilities. A pulley package consisting of pulleys, belts, bearings and seals cost on average approx. 5000 SEK. If the operating times can be extended from one year to two it means a saving of 2500 SEK per pulley package. If one assumes that each BTA is used to align 50 pulley packages a year it means a saving of 125,000 SEK.)
Transmissions with several wide belts are especially sensitive. It is easy to understand that the difference in belt tension between the inner and outer belts can differ greatly when aligned incorrectly. This reduces efficiency as not all belts are driven optimally. If one belt is worn then all belts must be replaced with new ones at the same time, which adds expense to the entire operation. Even wide belts are affected more as the tension is uneven over the entire width. Extending service life thanks to correct alignment is easy. Large savings can also be made when it comes to the cost of these types of belts and pulleys.