Mag Drive Pumps: Sealless Magnetic Drive Pumps for Zero-Leak Service
Sealless magnetic drive pumps sized to your fluid so aggressive and hazardous liquids stay contained, with parts and service across the Upper Midwest.
What is a mag drive pump and why specify one?
A mag drive pump, also called a magnetic drive pump, is a sealless centrifugal pump that transmits power to the impeller through a magnetic coupling instead of a shaft that passes through a seal. Because nothing rotates through the pump casing, there is no dynamic seal to leak. That makes it the default choice for corrosive, toxic, flammable, or high purity fluids where a weeping seal is a safety, environmental, or product-quality problem.
How the magnetic coupling works
An outer magnet ring is driven by the motor, and it turns an inner magnet assembly that carries the impeller. A stationary containment shell separates the two, sealing the fluid inside the wet end completely. The pumped liquid circulates through the inner assembly to lubricate the sleeve bearings and carry away the small amount of heat the coupling generates. There is no packing and no mechanical seal, which removes the most common source of pump leakage and one of the most frequent maintenance chores.
When a sealless design earns its place
- Hazardous or regulated fluids. Acids, solvents, and toxic media where a leak triggers safety, fugitive-emission, or reporting consequences.
- High purity service. Fluids that cannot tolerate contamination from seal flush or from wear particles.
- Expensive process media. When even minor product loss through a seal is costly over time.
- Seal-flush avoidance. Applications where you want to eliminate the seal support system, its plumbing, and its maintenance entirely.
Sizing a mag drive pump
Sizing follows normal centrifugal practice with two extra checks. First, confirm the fluid specific gravity, viscosity, and temperature, because these set the torque the magnet coupling must transmit; a heavier or thicker fluid demands more coupling capacity, and every coupling has a decoupling limit. Second, verify available NPSH against the pump requirement with margin, since flashing near the suction starves the internal lubrication path. Match flow and total dynamic head to the curve, choose wetted materials compatible with the fluid, and leave coupling headroom rather than running at the limit.
Failure modes and how to avoid them
The two biggest risks are dry running and abrasives. Because the liquid lubricates the internal bearings, a dry run can destroy the bushings in moments and overheat the coupling to the point of decoupling or demagnetization. Abrasive solids wear the sleeve bearings and can erode the containment shell. Guard against both by keeping the pump flooded, adding dry run or power monitoring where the risk is real, and reserving mag drive designs for clean fluids. When one does need service, our technicians rebuild the wet end, replace bearings and the containment shell, and verify coupling alignment before return to service.
Mag drive pump lines available through Brabazon
Brabazon supplies Magnatex sealless magnetic drive pumps and sizes them to your fluid, flow, and head. Send us the chemistry and duty and we will match the wetted materials and coupling to the service.
Industries that rely on sealless pumps
When a mag drive pump is NOT the right fit: if your fluid carries abrasive solids or runs the risk of frequent dry running, a sealless design will wear out fast. For solids-laden or dirty duty, a sealed pump built for the service is the better fit. Start with our pump category overview and we will steer you to the right type.
Repair and rebuild
Already running mag drive pumps? Our factory-trained technicians handle wet-end rebuilds, bearing and containment shell replacement, and coupling checks through pump repair and rebuild.
Mag drive pump questions, answered first
When should I choose a mag drive pump over a sealed pump?
Choose a mag drive pump when leakage is unacceptable, such as with corrosive acids, toxic or flammable liquids, high purity fluids, or expensive process media. Because the pump has no dynamic shaft seal, there is no seal to weep, no seal flush plan, and no seal room to maintain. If the fluid is clean, incompatible with a seal, or simply too hazardous to risk a leak, a sealless magnetic drive pump is usually the right call.
Can a mag drive pump run dry?
No, a standard mag drive pump should never run dry because the pumped liquid lubricates and cools the internal bearings and carries heat away from the magnet coupling. Running dry can wreck the bushings in seconds and can decouple or demagnetize the inner magnet if temperatures climb. If dry running is a real risk, specify a power monitor or dry run protection and size the system so the pump stays flooded.
What fluids are a poor fit for a mag drive pump?
Fluids heavy with abrasive solids are a poor fit because grit erodes the internal sleeve bearings and the containment shell quickly. Slurries, fluids that crystallize or set up when idle, and liquids prone to flashing near the suction all challenge a sealless design. For dirty or solids-laden service, a sealed pump built for solids or a different pump type is usually the better fit, and our engineers can point you there.
How do I size a magnetic drive pump correctly?
Start with the required flow and total dynamic head, then confirm the fluid specific gravity, viscosity, and temperature so the magnet coupling has enough torque margin. Higher specific gravity and viscosity raise the horsepower the coupling must transmit, and every coupling has a maximum torque before it decouples. Verify available NPSH against the pump requirement, then leave headroom so the coupling is not run at its limit.
Talk to a Pump Engineer
Send your fluid chemistry, flow, and head and an engineer will size a sealless magnetic drive pump matched to the service, then quote sale or repair. We answer 24/7.
Request a quote or sizing review
Tell us the fluid, temperature, flow, and head and an engineer will size a Magnatex mag drive pump for your service. Urgent? Call 800.825.3222, answered 24/7.
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