scubasteve8099
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Are these marketing terms just 2 different ways to describe the same function/design of a submersible pump? If it is not, is one better than another?
Thanks,
Steve
Thanks,
Steve
"Floating Stack Design" Vs. " Floating Impeller Design"
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No they are not the same. "Floating impeller" or "Floating Stage" pumps have impellers that are not secured to the pump shaft. They can slide up and down on the shaft. The bottoms of these impellers actually touch or drag on the diffuser. The marketing gimmick is that the "floating stage" takes all the load off of the motor thrust bearing. While it certainly does this, now each impeller drags on the diffuser below it during down thrust conditions. This produces more heat at low flows and more wear on the impellers. Plastic impellers grinding against plastic diffusers causes more wear than if the impellers did not touch the diffusers. Through in a little abrasive like sand, and they wear even faster. However, the Celcon or Delrin plastic they use is suppose to be self lubricating. It will last pretty good. But the deeper the pump is set or the more back pressure it has, the harder the impellers drag on the diffusers. Pentair and Franklin are the only two I know of that make a "floating stage" design. The Pentair is has been around for a long time and works fine with a CSV, except that it doesn't drop in amps as much as a "floating stack" design. Franklin changed the old Jacuzzi "floating stack" design to the "floating stage" design, and Franklin claims they do not last when used with a Dole valve or any kind of restriction. Sounds to me like Franklin just downgraded their design to further planned obsolescence.
A "floating stack" design has all the impellers locked to the shaft and the whole "stack" can float up and down a little. The whole "Stack" is held up by the motor thrust bearing and the impellers do not touch the diffuser at all. The Kingsbury type thrust bearing in the motor is made to handle downthrust. There is a film of water between the thrust shoes and plate, so nothing touches which makes a completely frictionless bearing. Letting the thrust load be handled by a Kingsbury frictionless bearing will allow the pump to spin easier. This produces less heat and lower amp draws, especially at low flow rates where downthrust increases.
Some pumps like the Goulds have plastic impellers, but use the "floating stack" design so the impellers do not touch the diffusers. Any pump with Stainless Steel impellers like the Grundfos cannot use the "floating stage" design, as Stainless Steel dragging against Stainless Steel diffusers is not self lubricating and would lock down quickly. However, the Kingsbury thrust bearing does a much better job of holding downthrust than plastic impellers grinding against plastic diffusers. There is also more tolerance between the impellers and diffusers with the "floating stack" design, which allows more room for debris to pass through without causing damage.
When water is just used for a house, the difference in amp draw between these two designs at low flow rates will not make much difference in the electric bill. But with a heat pump or irrigation system the lower amps from the "floating stack" design can make a big difference.
A "floating stack" design has all the impellers locked to the shaft and the whole "stack" can float up and down a little. The whole "Stack" is held up by the motor thrust bearing and the impellers do not touch the diffuser at all. The Kingsbury type thrust bearing in the motor is made to handle downthrust. There is a film of water between the thrust shoes and plate, so nothing touches which makes a completely frictionless bearing. Letting the thrust load be handled by a Kingsbury frictionless bearing will allow the pump to spin easier. This produces less heat and lower amp draws, especially at low flow rates where downthrust increases.
Some pumps like the Goulds have plastic impellers, but use the "floating stack" design so the impellers do not touch the diffusers. Any pump with Stainless Steel impellers like the Grundfos cannot use the "floating stage" design, as Stainless Steel dragging against Stainless Steel diffusers is not self lubricating and would lock down quickly. However, the Kingsbury thrust bearing does a much better job of holding downthrust than plastic impellers grinding against plastic diffusers. There is also more tolerance between the impellers and diffusers with the "floating stack" design, which allows more room for debris to pass through without causing damage.
When water is just used for a house, the difference in amp draw between these two designs at low flow rates will not make much difference in the electric bill. But with a heat pump or irrigation system the lower amps from the "floating stack" design can make a big difference.
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