Mount and grind

The correct mounting and dismounting of rolling element bearings can save time and dramatically increase the life of bearings, as well as maximise the availability of critical plant and machinery by avoiding costly breakdowns.

The key is to ensure that the appropriate tools and equipment for the mounting and dismounting of the bearings are on hand for the engineer at the installation or assembly stage.

Appropriate tools may include thermal mounting and dismounting tools (i.e. heating plates), induction-heating devices, mounting paste and heating rings, as well as feeler gauges, hydraulic extractors, hydraulic nuts and hand pump sets.

Using the correct tools ensures that bearings are mounted and removed easily and quickly without causing damage to the bearings or surrounding equipment.

Spanish leader

Grupo Cementos Portland Valderrivas is the largest group of cement manufacturers in Spain and one of the world leaders in the industry.

The annual production capacity of the El Alto cement plant, for example, is approximately 2.25 million tonnes of grey clinker; 230,000 tonnes of white clinker; 2.8 million tonnes of grey cement; and 280,000 tonnes of white cement.

There are two production lines at the plant for grey cement and one line for white cement. Portland Valderrivas had contracted one of the leading engineering service providers to the cement and mineral processing industry.

Four bearings in the company’s roller press had to be replaced, as these had reached the end of their maximum service lives.

The press is critical to the cement production process. The grinding process must produce a very fine clinker in order to guarantee a high quality final product. If the press does not operate correctly, the clinker produced does not meet these requirements.

Portland Valderrivas therefore contracted Schaeffler to carry out the mounting of the new bearings and to show the engineering service provider’s fitters exactly how to do this.

The four new bearings provided by Schaeffler were spherical roller bearings with tapered bores. The bearings each weighed 1650kg and measured 630mm x 1090mm x 336mm.

Due to the large size of the bearings and the importance of the press to the production process, correct bearing mounting was of vital importance, not only to the quality of the finished product, but also to plant availability.

During the mounting procedure, service experts from Schaeffler conducted on-site training for the fitters. The four new bearings were mounted using a hydraulic mounting tool. Adjacent components and bearing seats were checked to see if they could be reused.

Cost benefits

Due to the joint efforts of Schaeffler and the engineering service provider, the risk of a bearing failure, which would have resulted in two days’ unplanned downtime, was reduced significantly.

In addition, the transfer of knowledge from Schaeffler to the fitters enabled the engineering service provider to correctly carry out similar bearing mounting tasks without assistance in the future.

Schaeffler claims the costs of providing professional standard bearing mounting services at El Alto were far outweighed by the benefits. It says the work, including crane hire and the four new roller bearings, cost €138,000.

The cost of a bearing failure and two days’ lost production at the plant would be €240,000.

In addition to working onsite with plant owners, Schaeffler has launched an online, interactive information guide to help companies correctly mount and dismount rolling bearings.

The Schaeffler Mounting Toolbox shows users how to professionally install rolling bearings and the tools required to do this.

As well as learning about which tools and fitting aids are required, users can also view short educational videos that demonstrate how these tools should be used in practise.

On entering the website (http://mountingtoolbox.schaeffler.com) users are presented with a ‘Virtual Plant’ home screen, which serves as the main user interface.

The objective is to make users feel that they are actually in a factory, looking over the shoulder of a Schaeffler professionally-qualified mounting service technician, who is demonstrating how to correctly mount the bearings.

The website provides details of mounting tools and accessories, and demonstrates the benefits of correctly mounted rolling bearings, which include longer operating life for the bearing, reduced unplanned downtime, and higher machine availability.