[TheForge] microwave heavy metal session

Thu Feb 12 16:33:00 2004

I talked with the fella.

About 20 years ago they used klystrons primarily for heating of glue in =
the
manufacturing of plywood.  There are still some used in various
applications. =20

There are some available on the used market (the tubes) in the several
thousand dollar range.  Thompson CSF as he remembers.  They were in the
power range of 50-100 kW output.  Combining more than one to operate
together is a non-trivial task.

Though it is possible to use microwaves for metal heating, for large
quantities, or continued application, he recommends using rf induction
heating. =20

The microwaves will penetrate until they see metal, then the metal will
conduct, and internal heating will be by conduction.  With induction
heating, you can get real internal heating.

It can be done, but does not appear to be an optimum thing to do<G>.

-----Original Message-----
From: [email protected] =
[mailto:[email protected]]
On Behalf Of Jerry Frost
Sent: Thursday, February 12, 2004 3:50 PM
To: [email protected]
Subject: Re: [TheForge] microwave heavy metal session

----- Original Message -----
From: "Andy Vida" <[email protected]>
To: <[email protected]>
Sent: Thursday, February 12, 2004 11:21 AM
Subject: Re: [TheForge] microwave heavy metal session

>
>
> Grover Richardson wrote:
> >
> > Magnetrons (the ones that I have seen, and that's a bunch) vary=20
> > between
30
> > and 60% efficiency.  This does not include losses within the power
supply.
>
> In that case, it's no wonder they don't use it.

A purpose built unit would probably operate at or near the 60% end of =
the
curve.

Compared to sucking up 70%+/- of a given fuel's BTUs by heating the =
nitrogen
in air added to DIRECTLY heating the interior of a furnace it sounds =
like a
cash cow to me.

Consider the microwaves DIRECTLY heat only the metal in the crucible.
There's no need for room for combustion nor circulation of hot gasses, =
the
smaller the "furnace" the better. I'd just wrap the crucible in =
refractory
blanket and do away with a "furnace" altogether. Sure you'd have to have =
an
enclosure to keep microwaves in and people out but it'd be nothing like =
a
furnace.

Injecting oxy for Bessimer steel doesn't happen in the furnace normally, =
so
that's not an issue.

All in all I think it's probably at least twice as cost effective even
considering the cost of electricity.

Maybe the USA will get back into making steel.

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.

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