Recently, a member of Readco’ service team travelled to a client’s production facility to oversee the replacement of several key components of a Readco 8” Continuous Processor, installation of new elements, and support the start-up operations. The top end of the CP’s transmission needed to be rebuilt due to normal wear and tear of continuous 24/7 operation. Among the parts being replaced were paddle shafts, feed screws, paddles, bearings, and spacers.
Shafts typically have keyways cut into them to hold in place the interchangeable paddle arrangement which is specific to the process. Additionally, the transmission end of the shaft is keyed to be driven by the drive gear inside the transmission. Often times in order to accept a new paddle arrangement, one of the gears – in a dual shaft configuration – must have a new key way cut into it so that the shaft can be rotated to accommodate the new arrangement in conjunction with its partner shaft. While the hardened gear was being re-keyed, the service staff took the time to replace the bearings, keys, and seals.
Once the gear was re-keyed, the unit was reassembled and ready for start-up. Start-up consisted of a cleaning process with the machine running to flush any foreign material or metal out of the unit before being added into the production line. Once switched over to production, the operators ran through the typical rates and sequences. During this, it was noticed that the machine was using more horse power than usual and the necessary RPM needed to be higher than normal to achieve the preferred loading and agglomeration. This was likely due to the change in radial clearance from the installation of new paddles – preventing the machine from reaching the previous top rate of production. Additionally, while trying to achieve this top rate, the motor faulted out due to overdraw and the RPM was decreased in order maintain operation.
An anomaly during the second shift run caused the run process to lose agglomeration and the system self-faulted. Upon start-up a coupling was sheared – which needed replaced -and the gear motor sounded abnormally loud. It was discovered that the operators erringly started the machine with a full load. Our service engineer recommended a procedural step to avoid this from happening again for future start-ups. Once the machine was run through the revised start-up procedure it was initially put back into production at the reduced rate to avoid over-loading. Throughout the next couple of hours the operators were able to steadily increase horse power and RPM, however, it was noticed a near proportional increase in temperature.
Our service engineer advised that they continue to maintain process and watch for stable operation. This is where Readco’s experience and expertise really came in to play. It was determined that the newly installed elements were very slow to reach thermal equilibrium due to the discharge temperature change. Additionally, the horse power and RPM change was be due to the same factor causing a slow closing of clearances until the elements were at uniform thermal expansion with the CP’s barrel. Shortly afterward, discharge temperature stabilized as did the horse power and RPM of the CP. After a full 12 hour shift runtime, all on hand were very pleased with the operation and production of the CP.