Both canned motor pumps and magnetic drive pumps are sealless, so neither has a shaft seal that can leak. They get there in different ways, and the difference matters when you choose one for a hazardous liquid.
How Each Design Works
Magnetic drive pump. A standard electric motor sits outside the pump. Torque passes through a magnetic coupling across a containment shell, so the pumped liquid never touches the motor side.
Canned motor pump. The motor rotor and stator are inside the pump casing, separated from the liquid by a thin metal sleeve called the can. The pumped liquid cools the motor and lubricates the bearings. There is no coupling at all.
Where Canned Motor Pumps Fit Better
- Higher pressure and temperature duties, because the motor is inside the pressure boundary
- Liquids where a decoupled magnetic drive would be a hazard, since a canned pump has no coupling to slip
- Applications that need very low maintenance, with no coupling and no alignment
Where Magnetic Drive Pumps Fit Better
- Standard motors that are easy to replace or repair in the field
- Lower pressure chemical transfer where cost matters
- Plants that already stock standard motors and spares
What They Have in Common
- Neither can run dry, because the liquid lubricates the bearings
- Both suffer if the liquid carries abrasive solids or magnetic particles
- Both are normally specified to API 685 in refinery and petrochemical service
- Both need good monitoring to catch bearing wear early
How to Choose
Start from the liquid: its hazard, temperature, vapor pressure, viscosity and solids content. Then check pressure, the hazardous area classification and the maintenance capability on site. When in doubt, share the datasheet and we will help you compare the options. See our canned motor pumps page, and read API 685 explained.
Talk to Power Energy
Send us the liquid, temperature, flow, head and area classification. Call or WhatsApp +966 56 278 9535 or email sales@powerenergy.com.co.