Lance type, helical or oscillation blowers are normally provided with a rigid coupling between axial movement and rotation and/or oscillation. This causes the core jet of the nozzles to clean always the same areas of the heating surface and to increase erosion. In Fig. 1 this mode of operation corresponds to an individual cleaning curve which is repeated in exactly the same way in each operation.

A standard fitting of the high-quality sootblowers of Clyde Bergemann is the multiple blowing pattern. This patented process is ensured by a maintenance-free friction coupling in the gearing. This allows an interruption of the axial movement of the blower carriage while the motor is running. The interruption is effected at the revising position of the blower with precise coordination with the electronic control which continues the rotation and/or oscillation for a few seconds. This changes the nozzles position in relation to the axial movement and the core jet will always clean different are as of the heating surfaces. Fig. 1 shows the possible multiple blowing pattern between the cleaning curves of the first four blowing cycles.

The Clyde Bergemann multiple blowing pattern has the following advantages:

• Cleaning is effected regularly and completely because each heating surface area is cleaned by the core jet of the nozzles during several blowing cycles.
  
• The erosive impact to the heat surface is reduced because in each blowing cycle a different heating surface area is cleaned.