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Differences between mechanical seal, sealless magnetic drive pumps

Supplier: Global Pumps
08 February, 2012

There are two broad categories of pumps used in the industries: pumps with mechanical seals and sealless magnetic drive pumps. Global Pumps explains the difference netween the two.

Mechanical seal pumps are mostly used and selected because of a lack of knowledge regarding mag drive pumps.

Some of the important points of comparison are:

1. Sealing of the fluid being pumped

In mechanical sealed pumps there is a mechanical seal that prevents the leakage of the fluid being pumped. However, some amount of fluid always keeps on leaking through the mechanical seal for its lubrication and cooling.

Some mechanical seals can be cooled by external fluids. In magnetic drive pumps no mechanical seal is required. There is a shell or containment part of the pump that forms a complete and sealed enclosure through which the fluid being pumped cannot leak - thus the magnetic drive pumps are sealless zero leakage pumps.

2. Wearing of the seal and maintenance

The mechanical seal comprises of moving and stationary parts which are in contact with each other. The faces and elastomers of the mechanical seal start wearing after certain period of time and the amount of fluid leaking through it keeps on increasing, having to be replaced from time-to-time.

Since the magnetic drive pumps contain no seals there is no wearing of its parts, so no replacements are required and therefore requires less maintenance.

3. Mode of driving or pump design

In traditional pumps with mechanical seals there is coupling between the driving motor and driven pump shafts for the transfer of power to the impeller.

This arrangement makes it necessary to have the mechanical seal to prevent leakage of fluid. In the magnetic drive pumps the drive shaft is surrounded by a set of magnets.

When this shaft rotates it transfers its magnetic field to the impeller shaft through the shell through which the fluid passes. Thus there are no opening involved in the magnetic drive pumps and a completely sealed enclosure is formed for the fluid.

4. Type of fluids being pumped or application

Though pumps with mechanical seals can be used for pumping hazardous fluids, some leakage of fluid may always be involved.

The inherent design of the magnetic drive pumps offer zero leakage of pump being fluid so they are highly reliable for pumping hazardous corrosive fluids, aggressive fluids, difficult to seal fluids, expensive fluids, pure fluid and slurries.

Magnetic drive pumps are made up of non-metallic components that offer outstanding corrosion resistance.

Global Pumps are a major distributor of Techniflo magnetic drive pumps in Australia and New Zealand.