Common Problems of Magnetic Drive Pumps

1. Magnetic Drive Pumps Won’t Be Catastrophically Damaged By Dry Running?

It is not always the case that a magnetic (Mag) drive pump is completely devoid of liquid when it experiences an upset condition, particularly when it is starved of product. The majority of the time, the liquid stays in the pump to help lubricate the bearings during brief upsets and to keep the bearings from breaking during brief dry runs. Upgrading standard silicon carbide (SiC) bearings to enhanced SiC bearings with diamond-like coatings significantly increases bearing strength and reduces the coefficient of friction to one-fourth that of standard SiC bearings.

2. Will The Pump’s Magnets Be Affected By Temperature Spikes?

It’s critical to choose the right magnet material for operating temperature. A power monitoring device can reduce or eliminate this concern because upset conditions can cause temperature fluctuations that affect the strength of the magnets. The lower power that is drawn by a mag-drive pump causes the monitor to trip, which in turn turns off the pump when the pump runs dry or against a closed discharge valve.

3. When A Magnetic Drive Pump Decouples, What Happens?

The magnets will be permanently demagnetized if a magnetic drive pump operates in a decoupled state for an extended period. However, this condition is also monitored by the same power monitoring device that monitors for temperature fluctuations in the pump curve. The drive pumps are not particularly susceptible to abnormal operating conditions because of their design. The power monitor is equipped to address any worries related to capacity, density, and viscosity. Numerous worries disappear when a power monitor is used correctly.

4. Is Magnetic Drive Pump Radial Loading Common?

When compared to standard, seal-type overhung pumps, a drive pump’s reduced radial loading is a significant benefit. The straddle-mounted design of the pump with bearings on both sides of its inner magnet makes off-peak operation more tolerant. This design also reduces radial loading and provides excellent stability.

5. What Does A Maintenance Schedule For A Magnetic Drive Pump Look Like?

The designs of mag-drive pumps typically provide an unmaintained lifespan of eight to ten years, sometimes even longer. In process applications, few sealed pumps perform as well.

6. Is It More Expensive To Repair A Magnetic Pump Than To Repair A Sealed Pump?

Seal less vs. sealed has been a hotly debated topic for a long time. However, in significant failures, this may be partially true. However, the total cost of a major mag-drive repair would be exceeded by the frequent repairs, including the replacement of often-expensive seals, over the lifespan of a conventional sealed pump. In addition, major mag-drive failures are uncommon if some of the aforementioned precautions are taken, such as power monitors, upgraded SiC bearings, and the appropriate magnet material. In many pump applications, mag pumps are viable, cost-effective options that can provide years of trouble-free operation, potentially saving pump users tens of thousands of dollars over the equipment’s lifetime.

7. Can Magnetic Drive Pumps Handle Process Fluids That Are Toxic Or Dangerous?

When dealing with hazardous fluids such as corrosive, noxious, and ultra-pure liquids in certain applications, the pump curve is proven to be trustworthy. A mag drive is unquestionably an option for handling pricey fluids as well.

The list can also include less “dangerous” fluids, such as liquids that, if spilled onto the floor, could cause an employee to fall. A gamble the executive’s office could find mag-drive pumps exceptionally alluring. Similarly, moving odorous process fluids with magnetic pumps can make working conditions much more pleasant.

8. A Magnetic Drive Pump’s Internal Rotating Components May Be Affected By Caution.

It is possible to set up magnetic pumps to withstand cleaning with acids. Because the pump curve needs to be cleaned regularly. This is a big advantage in applications that use food-grade oils from the processing process. Make sure to tell the manufacturer of your pump if your application requires frequent cleaning to ensure that it is outfitted appropriately.

Magnetic drive pump issues can be avoided easily. If you follow the preventative measures mentioned, your magnetic drive pump will almost certainly continue to function normally. Even though magnetic drive pumps aren’t the best option for every situation, they can be ideal for a lot of cases where you want to get rid of mechanical seals.

What is the Lifespan of Enhanced SIC Bearings?

To determine the definitive dry run times of pump size and service conditions, thorough testing is essential. Testing has demonstrated that the dry run time for pumps with less than 2 horsepower (hp) is only a few minutes, but for the smallest pumps equipped with DLC-coated bearings, this time can exceed an hour. The time before the bearing system becomes damaged decreases proportionally to the pump’s power input. For bigger pumps in the 50 or more hp range, while DLC coatings will in any case help, the time before harm happens remains very short. Bearing damage is likely to occur when the motor is energized to check the pump’s rotation when there are neither liquid nor DLC-coated bearings in the unit. Initially, failed SiC components are the first warning of possible damage caused by dry running. The SiC can shatter into small pieces as the liquid evaporates and the rotating ceramic components come into contact with stationary components. The pump’s shaft, rear casing, casing cover, and impeller—all of which are pricey parts—are further damaged by continued operation. Damage to the pump of this kind can be avoided.

How to Prevent Dry Running 

When a giant bubble of vapor or air vents through the pump without losing suction, tripping the pump can be prevented by setting the low trip point time delay to less than 2 to 3 seconds. Operating for longer than necessary to empty the suction line may result in costly damage to the pump, far exceeding any remains product that could potentially be present. In several business accounts, the pump owner will save money with a properly set power monitor.