I have a friend trying to implement a 600 mm dia LPG ring burner to
heat a LARGE casting to assist in dis-assembly of a very large beam
engine manufactured in the 1800's to pump water for Auckland City.
If anyone can offer any useful comments on suitable burner fabrication
it would be appreciated. Details below.
> Russell,
>
> I have been trying to build a quick-and-dirty LPG-powered ring
> burner for
> evenly heating a large expansion joint casting on the engine at
> MOTAT. I
> need a ring of flame (directed inwards) about 600mm in diameter.
>
> Initial attempts were a dismal failure. Research on the web
> suggests that
> it is not an easy thing to do if the ring is large and you need a
> substantial heat output. Gas dynamics fight agianst you at every
> turn. My
> experiments are continuing.
>
> Single point burners are relatively easier. An especially simple
> version
> (though I suspect the exposure used makes the flame form look better
> than it
> is in real life) is here:
>
> http://www.backyardmetalcasting.com/oliverburner1.html
>
> For sub-1mm drills (aolid carbide) this outfit may be worth a try
> (if they
> will ship overseas):
>
> http://shop.store.yahoo.com/drillcity/
>
> Regards,
>
> Ken Mardle
On Tue, 31 May 2005 17:35:16 +1200, Russell McMahon wrote:
> I have a friend trying to implement a 600 mm dia LPG ring burner to
> heat a LARGE casting to assist in dis-assembly of a very large beam
> engine manufactured in the 1800's to pump water for Auckland City.
>
> If anyone can offer any useful comments on suitable burner fabrication
> it would be appreciated. Details below.
The people to talk to would be the engineers at the Kew Bridge Steam Museum - they have restored (and continue
to do so) large steam engines, mostly to do with pumping water (the site is a former water pumping station).
I imagine they have already solved this problem.
http://www.kbsm.org - there is a gemeral email address under "Contact Details" (Duh! :-)
Incidentally, there was mention of difficulty obtaining sub-millimetre drill bits: Jan-Erik was selling them
from his web site a while ago - he may have some left!
On 5/31/05, Russell McMahon <.....ruslKILLspam@spam@paradise.net.nz> wrote:
> I have a friend trying to implement a 600 mm dia LPG ring burner to
> heat a LARGE casting to assist in dis-assembly of a very large beam
> engine manufactured in the 1800's to pump water for Auckland City.
>
> If anyone can offer any useful comments on suitable burner fabrication
> it would be appreciated. Details below.
>
> To: "Russell McMahon" <ruslKILLspamparadise.net.nz>
> Sent: Tuesday, May 31, 2005 4:25 PM
> Subject: burner design and implementation
>
> > Russell,
> >
> > I have been trying to build a quick-and-dirty LPG-powered ring
> > burner for
> > evenly heating a large expansion joint casting on the engine at
> > MOTAT. I
> > need a ring of flame (directed inwards) about 600mm in diameter.
LPG burner? Bah, far too pedestrian. This job calls for induction
heating. Low freqeuncy for a big coil and deeper pentration...
Little wasted heat... So, who has a (ds)PIC-based design for a
water-cooled RF power supply? I wonder how much power he needs?
>On 5/31/05, Russell McMahon <.....ruslKILLspam.....paradise.net.nz> wrote:
>> I have a friend trying to implement a 600 mm dia LPG ring burner to
>> heat a LARGE casting to assist in dis-assembly of a very large beam
>> engine manufactured in the 1800's to pump water for Auckland City.
>>
>> If anyone can offer any useful comments on suitable burner fabrication
>> it would be appreciated. Details below.
>>
>> To: "Russell McMahon" <EraseMEruslspam_OUTTakeThisOuTparadise.net.nz>
>> Sent: Tuesday, May 31, 2005 4:25 PM
>> Subject: burner design and implementation
>>
>> > Russell,
>> >
>> > I have been trying to build a quick-and-dirty LPG-powered ring
>> > burner for
>> > evenly heating a large expansion joint casting on the engine at
>> > MOTAT. I
>> > need a ring of flame (directed inwards) about 600mm in diameter.
>
>LPG burner? Bah, far too pedestrian. This job calls for induction
>heating. Low freqeuncy for a big coil and deeper pentration...
>Little wasted heat... So, who has a (ds)PIC-based design for a
>water-cooled RF power supply? I wonder how much power he needs?
>
>Bradley
RF? Just use mains frequency.
Run a number of thick turns around it and switch on ;)
This is very much in the "grey area" between EE and OT.
One of the biggest problems with topic tags, and a problem that gets worse
when you add more topics tags, is that it can be hard to see where something
belongs.
I personally would have started this out as EE, but I can see someone not
wanting to bother Electrical Engineers with it.
The admins are currently discussing the possibility of changing the EE tag
to TECH or just redefining it to mean "Everything Engineering"
On Tue, 31 May 2005 19:41:45, Roland <jemelectricspam_OUTmweb.co.za> wrote:
> RF? Just use mains frequency.
>
> Run a number of thick turns around it and switch on ;)
I wonder how that would work. My inkling is that it would heat the
coil more than the part, assuming that it was current limited. I
imagine the part is fairly ferrous, though, so it would be very much
like a transformer...
There is some used equipment (~12.5K USD) on the Ameritherm website.
It only goes down to 50kHz and delivers 3kW.
Induction heating was around long before inverters were. I was looking at an old book the other day, and many industrial kilns were induction heated using mains frequency, usually through a transformer.
Will post the title.
A transformer primary/secondary RESISTANCE is ideally zero, so the energy is stored in the iron laminates. Losses in the laminates are converted to heat. Normally, the objective is to minimise these. Short out all the laminates(crucible), and it'll get hot indeed.
>On Tue, 31 May 2005 19:41:45, Roland <@spam@jemelectricKILLspammweb.co.za> wrote:
>> RF? Just use mains frequency.
>>
>> Run a number of thick turns around it and switch on ;)
>
>I wonder how that would work. My inkling is that it would heat the
>coil more than the part, assuming that it was current limited. I
>imagine the part is fairly ferrous, though, so it would be very much
>like a transformer...
>
>There is some used equipment (~12.5K USD) on the Ameritherm website.
>It only goes down to 50kHz and delivers 3kW.
>
>Bradley
>
> On Tue, 31 May 2005 19:41:45, Roland <KILLspamjemelectricKILLspammweb.co.za> wrote:
>> RF? Just use mains frequency.
>>
>> Run a number of thick turns around it and switch on ;)
>
> I wonder how that would work. My inkling is that it would heat the
> coil more than the part, assuming that it was current limited. I
> imagine the part is fairly ferrous, though, so it would be very much
> like a transformer...
>
> There is some used equipment (~12.5K USD) on the Ameritherm website.
> It only goes down to 50kHz and delivers 3kW.
3kW is not nearly enough. A small handheld type torch is 3kW. He needs
something in the 30kW range probably. If I understand it right, at the
time they would pack the receiver end (with a hole about the diameter of
a man's thigh for a crank pin) into a basket with hot charcoal and leave
it there until dull red. Then they would hammer the pin in using huge
hammers and something in-between to prevent marring the pin. There is no
telling what this does to the heat treatment of the part (if any, since
it's Victorian technology).
On Wednesday, June 01, 2005 2:43 PM, Peter [SMTP:RemoveMEplpTakeThisOuTactcom.co.il] wrote:
> If I understand it right, at the
> time they would pack the receiver end (with a hole about the diameter of
> a man's thigh for a crank pin) into a basket with hot charcoal and leave
> it there until dull red. Then they would hammer the pin in using huge
> hammers and something in-between to prevent marring the pin. There is no
> telling what this does to the heat treatment of the part (if any, since
> it's Victorian technology).
>
Which brings up the question that I have been asking myself since I saw the
original post. Those victorian engineers would have realised that the thing
was likely to need dismantling at some stage in its lifetime. Applying heat
only to the female part prior to assembly could have happened exactly as
Peter says, because the two parts were physically separate. But how would
the victorians have applied localised heat to the female part without
heating, and consequently expanding, the male part to an equal extent if
they started with the two parts assembled?
The mechanisms of the Victorian era show the mechanics of those days were
very clever. Don't rule out the same heat sources (think Thermite) that they
used for welding and casting. for that matter, don't rule out the
possibility that the pin was in the original mold and the casting poured
around it!
I doubt disassembly was one of their big priorities.
> Which brings up the question that I have been asking myself since I saw the
> original post. Those victorian engineers would have realised that the thing
> was likely to need dismantling at some stage in its lifetime. Applying heat
> only to the female part prior to assembly could have happened exactly as
> Peter says, because the two parts were physically separate. But how would
> the victorians have applied localised heat to the female part without
> heating, and consequently expanding, the male part to an equal extent if
> they started with the two parts assembled?
The pin is steel and the crank or beam is cast iron. They have different
coefficients of expansion (and they should be in the right direction -
I did not check).
> The mechanisms of the Victorian era show the mechanics of those days were
> very clever. Don't rule out the same heat sources (think Thermite) that they
> used for welding and casting. for that matter, don't rule out the possibility
> that the pin was in the original mold and the casting poured around it!
Afaik if you do that with steel at those sizes then the casting will
crack when it cools (and it will de-temper the steel for sure). Most
victorian era mechanisms that worked for a long time were hugely
overdimensioned anyway.
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