Magnetic Coupling Solutions at Saudi Aramco (Advantages of Magnetic Couplings in Oil & Gas Applications IV)
There are positives and negatives to every decision made at a manufacturing plant. Will this component breakdown faster than the alternative? Should I consider spending more money now to save money later? Do I have the right maintenance plan in place if these components fail?
Couplings may have to deal with high vibration or rotation as well as pressure spikes in oil and gas applications. Saudi Aramco enhanced the components/systems used at their oil and gas facilities by incorporating magnetic coupling technology.
For example, a hydraulic coupling may solve torsional vibration, but the coupling may suffer from maintenance and efficiency issues. Here are some of the advantages of considering a magnetic coupling over a hydraulic or rubber-type coupling:
- The magnetic coupling is a zero maintenance coupling while an oil-filled hydraulic or rubber-type is not. They typically require spare parts and overhauls.
- The magnetic coupling has a greater ability to isolate and damp torsional vibrations transmitted through the shaft, compared to a hydraulic coupling or rubber element type.
- Magnetic coupling accepts very high misalignment while a hydraulic coupling requires precision alignment.
- The magnetic coupling is safer since it has no oil to leak and will not cause fires.
- The magnetic coupling fixed gap type can also make a change in driven shaft speed if needed, by using slip and separating the two machines. This is not possible with fluid or rubber types.
Retrofitting with a Magnetic Coupling
You’ve made the decision to utilize magnetic coupling technology for your oil and gas application. What’s next? How can you ensure a problem-free retrofit when replacing standard conventional couplings with their magnetic counterparts?
Unless a variable speed drive (VSD) is needed, request fixed gap couplings only. Fixed speed, air-cooled couplings are limited to 1,200 hp in an environment like Saudi Arabia.
Clear, concise, PDF-side view dimensions should be included (each skid with a close-up of the motor and pump) to ensure there is enough radial height to fit.
Request that the couplings be rated for ambient air temperature between 45 or 50 degrees Celsius depending on the location. The magnetic coupling should be a minimum torque-rated 1.25 x existing driven machine’s max-rated torque. For coastal applications, plants should request full stainless steel bolting.
For pump applications, require a minimum 8.0-inch spacer type coupling on sizes of 100 hp and above to allow seal removal. Also, plan to fabricate a new coupling guard since magnetic coupling diameters are larger.
The Technology Benefits
Over the course of this four-part series on oil and gas applications, we’ve learned that fixed and variable gap magnetic couplings offer advantages such as lower vibration, no maintenance, extended life, greater energy savings and a lower total cost of ownership.
The many engineering and manufacturing challenges associated with pumps in the oil and gas industry suggest incorporating magnetic coupling technology into these applications in order to save energy, enhance reliability and reduce vibration.
Next week we’ll examine magnetic couplings in an adjustable speed drive (ASD) that have been working issue-free for 8+ years aboard the USNS Sisler, a Navy cargo ship.