Craig Dunn Clark on tue 13 jul 04
grammatically challenged Texan
Ivor, whut thuh deval do ya meen by "...colloquil use of the interrogative
negative?"
Thankyou for clarification
At times, grammatically challenged Texan
Craig Dunn Clark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
----- Original Message -----
From: "Ivor and Olive Lewis"
To:
Sent: Sunday, July 11, 2004 11:55 PM
Subject: Re: Elec kiln elements wearing out too soon? Why?
Dear Phil,
Your colloquial use of the interrogative negative in both sentences
makes for confused understanding.
But I am sure the answer to your questions will be available
somewhere.
However, it is the choice of material for the elements and their
service conditions which determines their performance. As a chemical,
Kanthal A conductors running at high temperature will deteriorate in
the same way regardless of whether or not they are thick rods or thin
wires.
Now there was a time when I had charge of four furnaces which were
wound with pure Molybdenum (MP 2620º C ) rectangular strip and
immersed in a dry Hydrogen atmosphere.
I suppose the best thing is to treat Kiln elements as expendable items
and account for them correctly as maintenance replacements in the Cost
of Works column on the spread sheet..
Glad to hear you had a good time up north.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
----- Original Message -----
From:
To:
Sent: Monday, 12 July 2004 3:01
Subject: Re: Elec kiln elements wearing out too soon? Why?
> Hi Ivor, all...
>
>
>
> Why do Electric Kilns not use 'rods' instead of coiled
> 'wire'?
>
>
> Would they not be more durable?
>
>
> Phil
> el ve
>
>
> ----- Original Message -----
> From: "Ivor and Olive Lewis"
> > Dear Friends,
> > It would be good if we could have an explanation of the
> behaviour of
> > the effects of prolonged heating on furnace elements.
> > Since we may be dealing with several alloys it is
> reasonable to
> > suppose that their corrosion and wear processes are not
> identical.
> > As I understand things in a general way, repeated heating
> and cooling
> > causes grain growth. Provided the initial oxide coating
> remains intact
> > it is relatively impervious to gas diffusion. But if it is
> disturbed
> > by any cause then the oxidation process is renewed and
> proceeds along
> > the grain boundaries. This changes the conduction
> characteristics of
> > the element, creating places of increased resistance to
> current. The
> > effect is to cause hot spots where elements fail due to
> premature
> > melting.
> > Can anyone add more to this supposition?
> > Best regards,
> > Ivor Lewis.
> > Redhill,
> > S. Australia.
>
>
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