Zinc free Bronze Impeller for chilled water pumping
Zinc free Bronze Impeller for chilled water pumping
(OP)
Dear All
I request your expert advice on the below
For one of the chilled water pumping requirement, we are proposing a pump with CI casing and bronze impeller.
The consultant on the project wants the impeller to be Zinc Free.
Our bronze impeller contains 5% zinc in it.
I kindly request you to help me know on why Zinc is added in the bronze impeller.
what is the advantage of zinc free impeller over impeller with zinc
upto what percentage of zinc is recommended in the bronze impeller
please help me with your expert advise
regards
I request your expert advice on the below
For one of the chilled water pumping requirement, we are proposing a pump with CI casing and bronze impeller.
The consultant on the project wants the impeller to be Zinc Free.
Our bronze impeller contains 5% zinc in it.
I kindly request you to help me know on why Zinc is added in the bronze impeller.
what is the advantage of zinc free impeller over impeller with zinc
upto what percentage of zinc is recommended in the bronze impeller
please help me with your expert advise
regards





RE: Zinc free Bronze Impeller for chilled water pumping
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.)
RE: Zinc free Bronze Impeller for chilled water pumping
This is the problem, even he does not know I guess
he is just following the specs written by some one
please let me know if we can help him on this
regards
RE: Zinc free Bronze Impeller for chilled water pumping
RE: Zinc free Bronze Impeller for chilled water pumping
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.)
RE: Zinc free Bronze Impeller for chilled water pumping
If he/she doesn't know why they're putting something in the spec, he/she shouldn't be writing it.
RE: Zinc free Bronze Impeller for chilled water pumping
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.)
RE: Zinc free Bronze Impeller for chilled water pumping
RE: Zinc free Bronze Impeller for chilled water pumping
But most commercial bronze alloys do have some Zn.
Zn alone is no indication of resistance to corrosion or even de-zincification.
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P.E. Metallurgy, Plymouth Tube
RE: Zinc free Bronze Impeller for chilled water pumping
Thanks for you responses
I had a meeting this morning with the consultant regarding this matter and he informed that they will be using these pumps for drinking water transfer pumps.
he has no justification for the zinc free bronze but insisting in having them as he wants to follow the specifications.
regards
RE: Zinc free Bronze Impeller for chilled water pumping
Well in that case comply, if there is a major difference on price and delivery, put in an alternate price for standard bronze and let the consultant / end-user make the decision.
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.)
RE: Zinc free Bronze Impeller for chilled water pumping
There are alloys listed in NSF for drinking water service.
Artisi is correct, all that you do is provide options.
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P.E. Metallurgy, Plymouth Tube
RE: Zinc free Bronze Impeller for chilled water pumping
RE: Zinc free Bronze Impeller for chilled water pumping
Bronze tends to be a generic term. Many manufacturers stopped using the SAE-40 bronze (a common alloy used for impellers) 20 years ago because it contained 4.5% lead content. The SAE-40 bronze alloy was replaced with other bronze alloys that caused dezincification problems with impellers.
Since one does not know the exact chemical composition of the generic bronze that the pump manufacturers are selling, it is easier to specify zinc free to avoid the problem of dezincification.