What Differentiates Sealless Magnetic Drive Pumps from a Sealed Pump?

Posted: 7/19/2013

So what exactly are sealless pumps? What are the specific feature and performance characteristics that substantively differentiate a sealless mag drive pump from a good old fashioned mechanical seal pump? For those of you who don't already know the answers to those two questions, we've decided to devote this latest March blog post to explaining the ins and outs of a mag drive pumps advanced fluid handling technology as it were.

Generally speaking there are two broad industrial pump categories: pumps with mechanical seals and sealless magnetic drive pumps. In the simplest possible terms a sealless magnetic drive pump is just a traditional centrifugal pump with neither mechanical seals nor packed glands. In place of the dynamic seals that'd typically seal the pump's impeller shaft, you'll find a shroud (static containment shell) that forms a liquid pressure boundary. The "movement energy" of a sealless pump is conveyed through to the pump's sealed liquid end by an external bank of magnets that spin to transfer magnetic force from the containment shell fluids pass through.

Since mechanical seal pumps are designed to lubricate and cool themselves by leaking small amounts of fluid as they operate and because said leakage inevitably seep into the pump's operating environment, their use represents unavoidable process inefficiency. By contrast sealless pumps don't leak. Which is why sealless mag drive pumps have historically been used for hard-to-seal applications that involve hazardous or volatile chemicals.

Though mechanical seal pumps can be used for applications that involve pumping hazardous fluids, there will always be some leakage involved. Whereas by design, mag drive pumps are zero leakage affairs and therefore better for pumping corrosive, expensive or aggressive fluids. Centrifugal sealless magnetic drive pumps are also manufactured using only non-metallic components and therefore highly resistant to a wide range of chemical corrosives.

Similarly, because the seals of mechanical seal pumps have this tendency to wear down, lose their effectiveness as they do and leak ever greater amounts of liquid through their seals. Obviously that kind of "spillage" can decrease worksite safety and add expenses to a process over time. Since sealless magnetic drive pumps like the models we manufacture here at March Pump don't have seals, there are no parts to inevitably wear down. It's a feature that makes them a cost-effective and low maintenance alternative to traditional mechanical seal designs.

Don't get us wrong, there will always be applications better suited to mechanical seal pumps, because some of them can operate beyond of the fluid handling capabilities of sealless pumps. But inside the standard pump performance envelope, there are reasons ranging from reducing negative environmental impact and improving industrial safety to just plain reliability, to recommend the adoption of sealless magnetic drive pump technology.

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