FSM Uses Stationary Journal Machining to Reduce Turbine Downtime
An expanding array of machining options, including stationary journal machining (SJM), now make it possible to perform turbine repairs on-site. The big advantages are reduced cost and shortened outages.
SJM evolved from technology first developed in Europe in the early 1950s, though modern equipment bears little resemblance to the early models. “Previous catastrophic failures provide important lessons upon which to build more advanced and effective machining systems,” says Charles T Vollmer of Field System Machining (FSM), a South Elgin, Illiois-based company that specializes in SJM and large portable on-site machining. “Today’s emergencies call for a new-generation of stationary journal machining processes.”
With SJM, rather than having to remove the rotor and turn it on a lathe, the equipment attaches to a stationary rotor and rotates around it. This has several advantages. Because absolutely no shaft rotation is required, this method eliminates the risk of journal cogging, oil climb or bearing damage. In addition, the plant crane or rigging assistance is no longer needed to remove the turbine. Since the turbine remains in place, the process doesn’t tie up floor space.
“Journal and bearing failures will happen,” Vollmer continues. “It is comforting to know that SJM can quickly and efficiently get you back online and running with minimum downtime.”
FSM, which has a large array of on-site machining tools, designed and built its own SJM. It is a portable machining apparatus that enables the company to accurately machine shafts, journals, collector rings and other components by rotating around the part. It can restore straight, round or concentric conditions to within 0.0005in (0.5mm) final machine tolerances from virtually any position.
FSM receives dimensional information from the customer (the fastest option) or it sends a technician on-site to take measurements. The machine is then preassembled so that when the crew arrives on-site, it is preset for the journal size. In most cases, the setup is simulated on a computer-aided drawing program to assure a proficient operation. By performing the setup in the shop before shipping it to the job location, the setup time is reduced and, consequently, so is the downtime for the customer.