Why would a mag drive be impractical for non corrosive applications? 1

• May 3, 2022

• #2

TugboatEng

Marine/Ocean

Nov 1, 2015

12,065

US

There are mag drive pumps that can be run dry.

Mechanic seal pumps are no less sensitive to dry running.

Mag drive pumps are a great longer lasting option provided your fluid doesn't have a lot of magnetic particles in it.

Mag drive doesn't have a big presence in high power applications. I feel that while mag drive may double the cost of your pump you're talking hundreds of dollars and that is insignificant in the overall project cost.

 

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• May 3, 2022

• #3

EdStainless

Materials

May 20, 2004

16,364

Waukesha WI USA

I depends on the styles of seals that you run.
If you are currently running very complex seal patterns than a mag drive might simplify your life enough to justify it.
They are a different animal so be careful where you use them.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

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• May 3, 2022

• #4

stewbaby

Mechanical

Jan 29, 2003

98

US

Goulds has mag drives also so it isn't a mag vs Goulds thing really. Even if going mag, I'd still give Goulds a shot at it. A min flow spill back can help with that run dry concern. Only real drawback to your application, besides the initial outlay, would be the efficiency losses so maybe run that power consumption calc if your HP is up there since it sounds like it runs 24/7.

 

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• May 3, 2022

• #5

georgeverghese

Chemical

Mar 19, 2015

5,099

AU

Mag drive pumps are like the devil you dont know - find out first what you dont know yet. You most certainly wont hear of failures talking to vendors. Also trace components (whether intermittent or continuous) in this treated water may make a meal out of this "corrosion resistant" liner.

 

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• May 4, 2022

1
• #6

LittleInch

Petroleum

Mar 27, 2013

22,974

GB

The reason mag drives would not normally be chosen is because the primary aim when building plants is CAPEX.

Unless the client is very firm and has a lot of sway, OPEX costs, costs of shutdowns or stoppages etc, rarely enter the decision making process.

The MTBF is one way of assessing the issue, but if this particular unit was seen as critical then often its easier and cheaper to install a spare to prevent shutdowns and downtime on the plant.

This is something different which is a RAM study and could highlight certain areas where use of a MAG drive could be seen as cost effective.

But its not without pain as well. There are losses in the drive and the internal sealing sometimes leaks. This guy has had a lot of issues

https://www.eng-tips.com/viewthread.cfm?qid=490736

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

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• May 24, 2022

• #7

spartan117

Mechanical

Sep 12, 2018

18

US

Keep in mind there is a difference between magnetic drive pumps and canned motor pumps. The magnetic drive pumps have a coupling mechanism that is connected to a regular motor, while the canned motor pump contains the windings within the secondary containment shell and drives the pump shaft magnetic poles directly.

Also, magnetic drive pumps are offered in ANSI configurations with PTFE-lined internals for corrosive applications. However, there are just plain metallic magnetic drive pumps for normal process fluids.

As long as the hydrodynamic bearing is running (can request ceramic for dry running situations), the pump should be okay excluding other upset conditions like overloaded torque on startup. The motor can burn up if not properly monitored.

 

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