Induction Heaters

[cfordyce]

Looking for a company with expertise in custom induction heater applications. We have some induction heaters on a vessel that was built back in '67. two of the four heater coils have failed recently. We need a repair/replacement.

 

[nbucska]

Do you know the specs?

<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032

 

[RFTrax]

Induction heater coils are usually water pipes(for cooling) in an assembly that electrically isolates the quite pure water from a more general cooler via a heat exchanger. Provided you take it apart carefully, maintain the insulated places, you can re-make the shapes. Re-fill withde-ionised water. Make very sure that all other systems work!

But be aware that these coils, plus the meltable load, and large capacitors within are all parts of a resonant circuit. Various induction/vacuum furnaces have ways of altering the frequency to track the resonant point as it varies with the load. If its as old as '67, it just might have PCB oil in those capacitors, and maybe other places (oil-cooled transformers). Look up PCB, which I think means poly-chloro bi-phenyl, and appreciate the hazard of the stuff, and the expense of its disposal. "Consarc" and "Electrak" are some names I recall, but I don't know which companies sold them, or might have parts. I suspect that if you want to put a 30+ years old heater back into operation, you may have to roll your own - with some care!

 

[cfordyce]

My induction heater is Simply a coil of wire wrapped around a vessel. There is a mercury switch which closes and energizes the coil of wire with 575VAC (60Hz). This creates a field inside the vessel which causes current to flow within the internal metal baffels of the vessel. This causes them to heat up. In-turn heating the product within the vessel.

There are three coils altogether on this vessel.

Each rated at 10KW. Each draws ~30 to 35A when energized.

 

[RFTrax]

OK - so its a 40kW 60 Hz device. Induction heaters use the heating effect of eddy currents, and frequencies up to about 3kHz are used, Clearly a 60Hz version can use regular supplies from transformers possibly. If you have four coils, (which does not connect symmetrically to a 3-Phase supply), then I guess at transformer, and also possibly two sets of two parallel connected coils.

The structure sounds basic. Plain wire coils in an induction furnace are not a very wear-out item. Even if electrical kit is not your area of expertise, isolate the supplies (safety!!) and dare to look. The structures are essentially mechanical. The main degradation is likely to be at connection surfaces, corrosion, local heating, spillage and build-up, etc. Even if it comes to replacing the conductors, common sense rules. Supports and insulation are likely to require some care. Think about materials suited to the temperatures they might need to stand. If all thats needed is a clean-up, it is very likely you could contrive some help, if not do it in-house.
Of course... if each coil is driven from separate parts of the energy control kit, it might be as simple as finding the right fuses/contactors!

 

[cfordyce]

Thanks.

CAF

 

[inductionexpert]

We build induction for vessel heating.

http://www.AjaxTOCCO.com

Fred Specht

 

[cfordyce]

Fred, I met with a representative of your company. he was not interested in this work. Acttually, he refused to return to my Plant. His reasoning for this was due to our asbestos insullation on our piping??? Hard for me to believe that he designs induction heaters for vessels and has never run into asbestos containing insullation...

Anyway, I have successfully repaired the induction heater by simply rewinding hi-temp wire in the same manner as the original. System has been operational for 1 month now...


Thanks.

CAF

 

[inductionexpert]

Sorry our man gave wrong answers, do you recall his name?

 

[bogeyman]

The visitor with a morbid fear of asbestos was right, you should run too.

 

[Chaosiscash]

You can try Pillar Induction, up in Milwaukee. I've had success with them before.

Chaos