Paul B on sun 25 sep 05
I have to do a special modification to my burner ports. I am finishing up
my waste oil burners and have tested them with good results, but one thing
that suprised me about them is that they do not seem to need any secondary
air at all, and actually fire much cleaner with none. They use compressed
air to atomize the veg oil, i am running between 10 - 20 psi which is a lot
of air, but the air flaps on the burner blower, which is just like a forced
air gas burner, need to be closed completely, and the blast tube of the
burner needs to be sealed where it goes into the burner ports.
so the burner ports are square and the blast tube is round and i need to
take a piece of plate metal, cut a circle in it and mount it over the
burner ports and put a layer of kaowool in between the kiln and the metal,
and then the blast tube will fit right in there snug.
This would be easy to do if i know that you can take a concrete drill bit
and a hammer drill and drill into the hardbrick that make up the burner
ports and then anchor in using concrete anchors. But i wonder if you can do
this without making a mess, destroying the drill bit and cracking the
hardbrick. Has anyone ever done this, or does anyone have a better idea?
The burners will be set up so they can be moved back out of the ports when
the firing is done and the ports closed off.
By the way, vegetable oil burns really nice in this type of set up, the
flame is long and white hot, not bad for free fuel.
thanks,
Paul
Wayne Seidl on sun 25 sep 05
Paul:
DO NOT use concrete anchors. With the possibility of heat. the lead
in the lag shield (the part that goes into the brick) can melt, and
then you have a REAL mess on your hands, with melted lead and holes
you can=92t use again, not to mention loose port covers.
=20
Go to your nearest hardware/home center and ask to see their
"TAPCONS"=AE. You can buy a small box, (sometimes by the each
instead), and buy also the special sized drill for drilling the
holes into which they will be installed. One caveat, TAPCONS are
permanent. You cannot install and remove them and reuse the holes.
If you find that disassembly is needed, you would be better off
installing a metal bracket with TAPCONs to the concrete, then
bolting on whatever needs installation.
TAPCONs require only a 3/16 hole, so you should be able to drill and
not crack brick, as close as =BE inches apart. (I=92ve drilled them that
close together.) Let the drill bit do the work, don't try to power
through it, and you should be fine.
Best,
Wayne
=20
This would be easy to do if i know that you can take a concrete
drill bit
and a hammer drill and drill into the hardbrick that make up the
burner
ports and then anchor in using concrete anchors. But i wonder if you
can do
this without making a mess, destroying the drill bit and cracking
the
hardbrick. Has anyone ever done this, or does anyone have a better
idea?
pdp1@EARTHLINK.NET on sun 25 sep 05
Sorry, I missed the initial thread inquirey...
But, if you can access both side of the Hardibacker sheet, why not use a
Nut-and-a-Bolt ad some Washers?
I doubt the Hardibacker is thick enough for expanding lag-bolt retainers to
work well ayway...and being maybe brittle, self tappers might not work well
either.
I myself have ever drilled this material, but I will imagine any fresh
Masonary Bit would do it, and, to be nice, one should have some snug block
of Wood or something pressed agaist the back side, to ease how the Drill bit
goes through, and to reduce chipping there.
Phil
Las Vegas
Vince Pitelka on sun 25 sep 05
Paul -
I am confused as to why you would every want to bolt the burners to the side
of the kiln. Kiln burners shift, and that could cause problems. Also,
attempting to drill into the bricks could cause them to loosen and shift.
The only circumstance under which this would make any sense to mount burners
on the kiln face would be if there was a metal shell on the outside of the
kiln, as is the case with most commercially-made kilns that use sealed-face
burners.
It would be a simple matter to fabricate a floor bracket that is securely
bolted to the concrete slab, holding the burner flange firmly against the
burner port, with a kaowool gasket of course.
I admire you for pursuing this project, and I will be very interested in the
results. But I am curious as to why you are atomizing the veg oil with
compressed air rather than with a high-pressure pump and nozzle, as is used
in home and commercial oil burners. With proper filtering, I would think
that the vegetable oil would work fine in those burners, and they are
readily available new and used. Have you researched those burners for this
application?
Also, if you are atomizing with compressed air, what is the source of the
compressed air? Unless you have one hell of an industrial compressor, you
are going to be burning out compressors frequently if you keep them running
through the length of a glaze firing.
Don't mean to discourage you in any way. On the contrary, I find this
fascinating and I'd love to see it succeed.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Bruce Girrell on mon 26 sep 05
I have done this to allow for a door latch mechanism on a front-loading raku
kiln that I built. The brick does not disintegrate as you drill, assuming
normal hard materials drilling guidelines - carbide bit, drill away from the
edges, keep the bit reasonably cool.
Wayne's suggestion for TAPCONs is good. I used expansion bolts, which could
be removed if necessary. The downside of expansion bolts is that if you use
then too near an edge you can crack the brick if you tighten them too much.
But it sounds as though you won't need to support any real weight, so
minimal tightening should take care of things. I suppose that repeated
heat/cool cycles could loosen them but I have never tested that. As long as
the load is not along the axis of the bolts they could probably get pretty
loose and still do the job.
I doubt that TAPCONs would loosen much, but they may be more difficult to
install. The threads are intended for materials more like concrete and
cinder block. As hard as the threads are, it may be difficult be to get them
into firebrick. Again, since you have little weight to bear, choose a
shorter screw and you will be less likely to twist off the head during
installation. Get the specially sized TAPCON drill because the diameter is
critical.
Bruce Girrell
back to work now
Paul B on tue 27 sep 05
Vince,
thanks for the reply, i was hoping it would get your attention.
Anyway, to clear things up, i am not actually trying to bolt the burners to
the kiln, but instead to create a more-or-less airtight fit where the end
of the blast tube meets up with the burner port. The burner ports are
square and my previous burners were forced-air LP burners worked fine with
them, but the new burners do not work as well with so much secondary air.
There are adjusments on the blower intake to allow for more air when
needed, but for the most part you need a tight fit where the end of the
blast tube goes into the kiln. That's how the burners were made to work on
the residential furnaces they came out of.
so i was thinking of just covering up the square burner ports with a piece
of steel or something with a layer of fiber between, and cutting a circle
in the steel plate that the blast tube could slide in snugly and also be
moved back out of if need be.
Now, as for the burners, well yes there are two main designs for waste oil
burners, one is the pressure system you refer to and the other is
the "siphon nozzle" which uses very small amounts of air pressure,
sometimes as little as 3 psi, to both draw the oil up into the nozzle and
then atomize it into very fine mist. There is a fairly small group
(actually i think it is still very small) of people heating their homes
with waste veg oil and i met a few of them, they live in new england and
have been using the same system for a couple years now with no problems, so
i just went off their plans. They just took a home furnace with a Beckett
AF burner, built a preheater and installed the siphon nozzles with a
constant level device for the nozzle to draw the oil from. The preheater is
made from copper pipe and electric band heaters and it heats both the oil
to about 320 F and also heats the compressed air. I have pictures of all
this if you would like to see them let me know.
Honestly i am not sure what the adavantage is of siphon nozzles vs.
pressure feed systems, i just know that the people i met who use siphon
nozzles are getting very good and virtually maintenance free results - and
that is with furnaces that kick on and off all day long for months on end.
All i am doing is firing it up continously for several hours which makes it
even simpler.
Ordinarily, a very small compressor could be used for a home furnace but
yes, i will by using two burners and using more than 3 psi, probably at
least 10-15 and, although i think my 60 gallon shop compressor could handle
it i am thinking about plumbing in a secondary source of air just in case,
plus i use compressed air all the time anyway. The fact that i have not
bought fuel at the pump for my van since last December and may never buy
propane again makes the price of another compressor from harbor freight
seem quite cheap.
My plan is to do a firing on veg oil some time within the next few weeks
and as soon as i open the kiln i will know for sure how well it works. If
it works then it will cut my operating expenses for my studio in half, and
then i will report back more details about it.
thanks,
Paul
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