Adjustable impeller pumps

[OMNENG]

Dear Pump Experts,

I just came to know that there is a technology in the market that allows adjusting impeller vanes angle. I understand it helps in changing flow ranges of the pump while maintaining efficiency and head.

Do you have such pumps in your plants or portfolio of products? Are they doing the same job of VFD? In what applications they are used? Are they reliable or require costly maintenance?

If you already use some if them; I will be thankful if you can share the curves.

Enjoy week end

 

[ashtree]

There have been propeller pumps on the market for years with adjustable blade angle. These are typically large capacity relatively low head arrangements.

There are also a number of manufacturers who produce pumps with various modifications and adjustments to the inlet and outlets of the pumps to change the entry or exit of the pump to give a degree of variable flow operation. One particular pump manufacturer used what was referred to as a pre-rotator for wastewater pumps. At low tank levels the flow would come in via the pre-rotator so the relative velocity between the inflow and the impeller was lower and the pump rate would be reduced. This type had a special style of impeller though.

Just to pick up on your comment about changing vane angles and mmaintaining efficiency and head. It is unlikely that a variable impeller will be as efficient as a fixed unit that is optimised for a particular duty. The variable vane design will have a window where the efficiency is good but outside of that window the efficiency is likely to be poorer that a pump designed for that duty. Once you change the vane angle away from the optimum for that speed, flow etc the design will become a compromise even though it may change the flow to what is required.

Given that VFDs are reliable and comparatively cheap why not go this way.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

 

[EdStainless]

There are variable geometry applications in gas handling, but the technology is very specialized.

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P.E. Metallurgy, Plymouth Tube

 

[Artisi]

OP - complete lack of useful information as to what you are asking - what is the application, flowrates, head etc.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[OMNENG]

Artisi,you are scolding as usual

the flowrate: 20,000 m3/hr, Applicatio: sea cooling water; Head: 35 m

 

[Artisi]

Not scolding - just looking for useable data.
Yes there are variable pitch impeller pumps available, axial flow configuration although the 35 metre head might be a problem. You will have to search the net for manufacturers as I don't know who makes them now a days.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Artisi]

Just googled variable pitch axial flow pumps, two good leads on the first pages - go have a look.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)