Circulating pumps

[bernardgreen]

I have just changed a circulating pump on a sealed pressurised system which had failed due to water getting past the shaft seal and into the electrical area of coils and terminals. Since this appears to be a common problem with pressurised systems I was considering the next replacement ( if needed ) to be the type where the impellor is separated from the electrics by an impervious (to water) membrane. The impellor is driven by a rotating magnetic field that passes through the membrane.

With operating pressures of 2 bar the seal on the shaft of an "ordinary" pump has to be well designed and resilient.

Other than being less efficient and un-able to be "kick started" if they stick are there any other reasons why these membrane pumps are not used more often. ?

Bernard Green
Sharnbrook
UK

 

[doitall]

What the ferk are you talking about, the electrical bits are in a water tight tube.

If the pump is fitted correctly water will not get into the electrical dept.

 

[Paul Barker]

Other than being less efficient and un-able to be "kick started" if they stick are there any other reasons why these membrane pumps are not used more often. ?

UK

Sludge would stick the impellor and magnet may not have sufficient torque to move it.

 

[cross thread]

PUMPS ARE PERFECTLY OK ON SEALED SYSTEM ,BUT FIT A GRUNDFOS