Kettle testing and maintenance strategies are important for galvanizing plants. Regular testing of kettle walls helps identify thinning areas and determines when replacement is needed. New testing methods using submersible probes provide more data without needing to pump out zinc. Outsourced pump out and shutdown services can replace sections of thinning kettles molten and in only a few days minimize production losses. Data from more frequent testing could lead to combustion chamber design improvements to better distribute heat and extend kettle lifetimes.

1. Kettle testing and use – recent
developments
GAA Conference 2011

2. Critical asset
• The Kettle is a critical asset in your galvanizing
plant.
• Some examples of kettle value:
– Between 5-10 days of sales
– Between 10 – 25% of the zinc it holds
• Another aspect is the full replacement cost
including:
– New kettle
– Zinc losses from pump out/remelt (5-10%)
– Lost production
– Associated services

3. Kettle strategies
• Regular pump out testing
• Regular in service testing
• Fixed replacement timeframe
• Hope for the best

5. Testing
• Three types of thickness testing:
– External wall zinc cooled
– Internal wall – pump out
– Internal wall – submersible probe
• Kettle testing using submersible probes is now
well established and in use by many
galvanizing companies in Europe and USA with
some tests completed in Australia/NZ during
2010/11

6. KID testing

7. Testing (Continued)
• Significant downsides of the current
equipment include:
– Size (difficult to transport)
– Use of cooling gas
• Development of non cooled probes is
progressing.
• A probe owned by a galvanizing plant is now
conceivable

8. Outcome of more testing
• The more testing is done (particularly if by an
organisation who is able to aggregate the
data) then it becomes clearer to see the need
for greater understanding heat transfer into
the kettle
• Kettles that are replaced often contain
substantial surface areas above 40mm!
• This is a clear indication that there is
opportunity to improve CC performance

9. Wear maps

10. Combustion chambers
• Most kettles exhibit a similar pattern of wear
• For each square metre of wall thickness at or
below 30mm there will be at least 5 sqm of
wall at 40mm or above
• An even distribution of heat could extend
kettle life significantly – but at what cost

11. Kettle designs
• Relatively few changes to kettles have been
made over the last 20 years.
• The flared kettle or champagne glass design
has been around for some time now. Whilst
there has been some uptake this design is in
limited use in Australia.
• Only 1 built by Furphy Engineering.
• Chinese appear to be more adventurous.

12. Pump outs
• Pump out services involving molten transfer
are now common in Europe and North
America.
• Molten transfer vessels are electrically heated
and have a capacity of 80 tonne.
• Significant reduction in downtime – even with
only half of the zinc transferred molten.

13. Pumping out

14. Pumping zinc

15. Molten transfer vessel

16. Pumping into moulds

17. Cooling

18. Pumping zinc back into kettle

19. Outsourced shut-downs
• In addition to pump outs there are also fully
outsourced shut downs occurring – as in other
industries.
• Recent project involving kettle replacement was
as short as 4 days from last dip to molten metal in
the new bath!
• With the shortening of time offline made possible
by the molten transfer – these shutdowns can
occur outside normal shut periods such as
Christmas/Easter etc.

20. Use of jacking cranes

21. Kettle removed

22. Changeover works

23. Furnace re-lining

24. Stainless Steel
• Increased aluminum content requires different
bath materials
• The use of Stainless steel 316 in kettles has
been a recent development for Furphy
Engineering.

32. Thank you!