Sealless Magnetic Drive vs Mechanical Sealed Pumps

Posted on by R Andrew Springer

What is a sealless magnetic drive pump?

A sealless mag drive pump is a conventional centrifugal pump without the dynamic seal that would normally be used to seal the pump shaft. This dynamic seal is replaced by a static containment shell to form a completely sealed liquid end or pressure boundary.

Sealless centrifugal pumps with magnetic drive have been around the industry for 70 years now. They offer plant engineering contractors and operators a 100% leakage free pump associated with the highest operational safety, low maintenance and adherence to strict environmental standards. As a matter of fact, mag drive pumps are displacing centrifugal pumps with double mechanical seal as they are have proved to be a greater cost-effective solution for hard-to-seal applications and the handling of hazardous, volatile and aggressive chemicals.

Reasons to choose a sealless magnetic drive pump vs a mechanical seal pump

Sealless Magnetic Drive Pump

Pump with Double Mechanical Seal

Mag Drive no leaks or spills
Leakage to the atmosphere

Zero leakage and total control of fugitive emissions, making these pumps environmentally friendly and clear option for handling hazardous or volatile chemicals. Leakage of the barrier fluid to the atmosphere, requiring additional monitoring of fluid level in the reservoir.

Mag Drive simple installation
Installation & Maintenance

Quick and easy installation, no requirement for external piping for seal flush, no complex seal support system. Maintenance-free sealing by containment shell, contact-free power transmission. To avoid the dry run of the mechanical seal, it has to be permanently supplied with liquid. Without this lubrication, the sealing will be damaged. This means the plant operator has to provide appropriate extra flushing connections and constantly monitor fluid levels.

Mag Drive efficiency

As the pumped liquid lubricates and cools down the magnet drive, no additional monitoring of the magnet coupling is necessary. It is recommended to track the temperature in the containment shell, though. Require permanent monitoring of pressure and temperature of the barrier fluid in the mechanical seal.

Mag Drive cost effectivenes

As magnetic drive pumps require less monitoring and maintenance, equating to maximized efficiency and substantial savings over the life of the pump. Mechanical seals must wear, resulting in costly maintenance programs, expensive repairs and longer downtimes.

Mag Drive increased durability
Bearing Load

Due to the two-parted shaft, less mechanical loading of shafts and bearings. High bearing loads, consequently causing the mechanical loading of the shaft. This could cause the grinding of the impeller in the pump casing or even more leakage of the mechanical seal.

Mag Drive reliability
Resonance Frequency

Its short design length consequently causes a high natural frequency of pump shaft. That means the resonance frequency is essentially higher than the speed of the pump. The overhung impeller results in a relatively low natural frequency of the pump shaft. A lower resonance frequency than the speed of the pump can cause dangerous vibrations during the pump start-up and shut-down.

Mag Drive product security

By eliminating the use of dynamic seals, magnetic drive pumps are the safest and most robust equipment for chemical transfer. Traditional seals are designed to lubricate and cool themselves by leaking small amounts of the pumped fluid as they operate, representing unavoidable fugitive emissions and jeopardizing working conditions.

Why choose a Ruhrpumpen Magnetic Drive Pump?

Ruhrpumpen’s experience through +65 years of pump technology manufacturing, has resulted in the world’s biggest companies using our pumps for heavy chemical handling applications. Since 2010, Ruhrpumpen has manufactured highly efficient and complete range of centrifugal pumps with magnetic drive acc. to DIN EN ISO 2858 and 15783 for the chemical industry, as well as heavy-duty process pumps with magnetic drive acc. to API 685 for the petrochemical industry. Our magnetic drive pump range can handle more than 150 different chemicals, plus a large number of different mixtures in DIN/ISO and API configurations.

CRP-M Mag Drive Process Pump

Our type CRP-M centrifugal pump with Permanent Magnetic Drive has been designed and built with the latest engineering techniques and tools such as 3D modelling, Finite-Element Analysis and CFD Simulation. In the same fashion, our SCE-M process pump with Magnetic Drive is based on the already well proven design of its API 610 counterpart (see SCE pump range) and offers over 130 hydraulic combinations to meet almost all of our customer requirements.

Ruhrpumpen engineering team of industry experts have worked in the development and execution of innovative designs for our sealless magnetic drive pumps. Up to now, 9 patents have been granted to our magnetic driven pump research and development team and incorporated within our mag drive standard pump builds, namely:

  • Internal Flows and Pressures (patent granted)
  • Journal Bearing Design (patent granted)
  • Axial Thrust Balance
  • Fastening of Zirconium Oxide Containment Shell (patent granted)

Article Originally Published by Ruhrpumpen Group Website, part of Corporación EG