Polyurethane Process Industries, LLC


Magnetic Couplings

Where the customer comes first

End pump seal maintenance and chemical leaks with wear-free magnetic couplings.

Magnetic couplings improve the reliability, safety and efficiency of polyurethane processing by eliminating the need for drive shaft seals in the metering pump.

Mechanical shaft seals, which separate the drive motor from chemicals in the metering pump, deteriorate over time and cause leaks. Magnetic couplings enclose the drive shaft in an airtight housing. There are no mechanical seals. Permanent magnets in the coupling’s nested rotor system transmit the high drive torque through the coupling enclosure, providing wear-free operation and overload protection.

The airtight, leak-free design makes magnetic couplings an ideal technology for meeting environmental and safety requirements associated with processing the more toxic, aggressive or flammable components used in some polyurethane foam applications.

Magnetic Coupling Cooling

On 28 cc/rev and larger metering pumps, cooling is critical to prolong coupling life. We offer a "full flow" cooling option that eliminates the need for auxiliary cooling pumps or circuits. With this option, fluid is piped from the day tank into a coupling inlet port, and then from the coupling to the metering pump inlet port.

How Magnetic Couplings Work

A magnetic coupling consists of two nested rotors, each with its own set of permanent, rare earth magnets.

The outer rotor mounts to the motor drive. The inner rotor, which is housed within an airtight, cup-shaped, stainless steel or ceramic enclosure, mounts to the metering pump and drive shaft.

As the motor drive turns, the magnets in the rotors transmit the torque through the walls of the airtight fluid barrier turning the pump shaft. If the maximum torque is exceeded, the coupling breaks transmission, providing overload protection.

Upgrade Your Existing Metering Pumps

We have magnetic coupling conversion kits to fit most major metering pump / motor drive combinations.

Conversion is fast and easy. Our process experts can help you determine the kit that will best satisfy the torque and mounting requirements of your application and metering pump / drive motor combination.

PPI also supplies new Rotary Power and Rexroth metering pumps with magnetic couplings installed.

Selecting the Correct Magnetic Coupling

It is important that the magnets, enclosure material and mounting flanges are sized correctly for your process and metering pump / drive motor combination. Ceramic coupling enclosures are available for process temperatures greater than 250° F (120° C).

Our process experts will assist you in selecting the correct conversion kit for your process.

We need to know the following information:

  • Metering Pump - manufacturer and model number.
  • Drive Motor - manufacturer, model number, HP, RPM and frame size.
  • Process Conditions - isocyanate and polyol viscosity, operating temperature and maximum temperature.
  • Metering Pump Inlet Pressure - feed pressure from pressurized tank or low-pressure feed pump.

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Image - Magnetic Couplings


  • Reduces maintenance and downtime
  • Reduces environmental problems
  • Improves operational safety and reliability
  • Works with most metering pump / drive motor combinations
Image: How magnetic coupling works


» Magnetic Coupling Conversion Kit:

Related Links:

» Metering Pump Repair Services
» Metering Pump Parts