27 Minute Coupling Hub Removal

November 11, 2020 ·
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Red-D-Arc Welderentals

Rotating Equipment Induction Heat Application

Red-D-Arc’s latest customer success story highlights the benefits of using induction heating in rotating equipment applications.
A client contacted Red-D-Arc to inquire about the use of induction heating to remove a coupling hub from a motor shaft. The hub was 12 inches in diameter and roughly 4 inches thick.

The overall work scope was straightforward: the client needed to remove an old motor and replace it with a new motor. The coupling hub had to be reused, so the hub would need to be removed from the old motor and installed on the new one. Two things made this job challenging: the location and the time limit. The work was to take place on an offshore platform. Use of an open flame was not an option, as it would have led to a safety violation.

Quick Heating Required

Time was also of the essence. The end user had a 48-hour permit to shut down their gas recovery compressor, which meant that the motor job had to be completed within the same window. It would have taken too long to ship the motor to land via boat, perform the work at a local shop, then ship the motor back. The cost of the boat run also would have been prohibitive. Red-D-Arc’s personnel were confident in their ability to support this job, given their experience with similar applications in natural gas compressor stations.

“The entire induction heating process, from the initial set up to the shut down of the machine, took only 27 minutes.”

Training Provided

To set the client up for success, Red-D-Arc provided a two-hour training session for one person at Red-D-Arc’s Houston facility. While the client was familiar with the process of induction heating, he was new to the Miller® brand of equipment. The training focused on the Miller ProHeat™ 35 liquid-cooled system. The ProHeat 35 is rated for an output of 35 kW, and it can be used to achieve temperatures of up to 1,450 degrees Fahrenheit. It can be operated in a manual programming mode or in a temperature-based programming mode.
Once the client was comfortable with the system and the training was complete, the work in the field began.
The client first set up a hub puller/strongback assembly, then added a hydraulic load cell to put pressure on the hub installed on the old motor.
Next came the induction heater. This setup included the ProHeat 35 with 30 feet of liquid-cooled heating cables, a short extension cable, and 12-inch-diameter blanket. It took 10 minutes to set up the ProHeat 35 and wrap the induction lines around the hub.

Heating Safety Requirments

With the restriction on open flames, the operator was unable to tack the thermocouple wires to the hub for temperature readings. The solution was to use the ProHeat 35 in manual mode, where the operator would be in control of the time and temperature. Two handheld infrared temperature guns would be used to monitor and track the hub temperature.

Once everything was set up, the operator started the machine and let it stabilize for about 10 minutes. Next came the heating process. The operator allowed the temperature of the hub to rise while holding the ProHeat 35 at 27 kW. He then paused and placed the unit on hold. The output was adjusted to 33 kW and the process ran again.
Within seven minutes of starting the heating process, the hub temperature rose to 370 degrees Fahrenheit. The hub then “popped”, and the client was able to pull the hub off the shaft. The client then moved the hot hub to the new motor, where it was easily installed.

27 Minute Turnaround

The entire induction heating process, from the initial set up to the shut down of the machine, took only 27 minutes. The client was able to complete the job safely and on time.
This success story is just one example of how induction heating can be used to support rotating equipment maintenance.

Induction heating is perfect for interference fit coupling applications on pumps, compressors, and other turbomachinery. Whether your equipment is in a compressor station, power generation plant, pipeline pump station, or any other production facility, Red-D-Arc can help.

Contact one of our induction heating specialists today for support with your rotating equipment applications.

Red-D-Arc Welderentals

Red-D-Arc Welderentals™ an Airgas company rents and leases welders, welding positioners, welding-related equipment, and electric power generators – anywhere in the world. Our rental welders, positioners and specialty products have been engineered and built to provide Extreme-Duty™ performance and reliability in even the harshest environments, and are available through over 70 Red-D-Arc Service Centers, strategically located throughout the United States, Canada, the United Kingdom, France, and the Netherlands, as well as through strategic alliances in the Middle East, Spain, Italy, Croatia, and the Caribbean. From our rental fleet of over 60,000 welders, 3,700 weld positioners, and 3,700 electric-power generators, we can supply you with the equipment you need – where you need it – when you need it.