dianamp@COMCAST.NET on sat 23 jun 12
Hi again:
These are questions about the same catenary kiln (about 35 cu. ft. load) ma=
de of IFB,
that I asked about a few weeks ago.
We have found some very nice burners that each put out 375,000 BTU's.
Which means that two of them at max would put out about 3/4 of a million
BTU's. I built kilns this size before with more and smaller burners and mor=
e total power--
a million BTU's, but never used that million, ever.
So, do you think there is anything wrong with two natural gas burners that =
big
for a kiln that size, one on each side running parallel to the sides of the=
kiln,
flame inside the bag walls, but in opposite directions.
They would not need blowers--are high quality cast iron
inspirating type with flame retention nozzles. Not home made.
The gas meter can be moved to within a few feet of the kiln.
Do you have any idea what water column pressure would be needed,
if we do use them? I never did learn how to figure out WC Pressure.
Thanks for any advice.
Sincerely,
Diana Pancioli
Eric Ciup on sat 23 jun 12
I have two points to make. First, when using 2 burners in a downdraft
kiln I place them on either side of the chimney so that the flame path
is as long as possible before reaching the flue. The way you propose to
do it you would have one burner with a long flame path and one with a
much shorter path. This could lead to uneven heating from side to side
although the turbulent atmosphere will probably even things out. The
plumbing of two burners on one side would be more straightforward than
kitty-corner burners.
Secondly make sure your meter can supply you with the needed gas. I
once had a studio that had an industrial sized meter that we had to pay
rent on. To save money we switched it out for a residential sized meter
which was rent free but it was only barely able to supply enough gas to
fire our kiln in 12 hours. After I left the studio, they rebuilt the
kiln as a sprung arch instead of a flat top and the firings took 2 to 3
days to reach cone 9.
Eric
> Hi again:
>
>
> These are questions about the same catenary kiln (about 35 cu. ft. load) =
made of IFB,
> that I asked about a few weeks ago.
>
>
> We have found some very nice burners that each put out 375,000 BTU's.
> Which means that two of them at max would put out about 3/4 of a million
> BTU's. I built kilns this size before with more and smaller burners and m=
ore total power--
> a million BTU's, but never used that million, ever.
>
>
> So, do you think there is anything wrong with two natural gas burners tha=
t big
> for a kiln that size, one on each side running parallel to the sides of t=
he kiln,
> flame inside the bag walls, but in opposite directions.
>
>
> They would not need blowers--are high quality cast iron
> inspirating type with flame retention nozzles. Not home made.
>
>
> The gas meter can be moved to within a few feet of the kiln.
> Do you have any idea what water column pressure would be needed,
> if we do use them? I never did learn how to figure out WC Pressure.
>
>
> Thanks for any advice.
>
>
> Sincerely,
>
>
> Diana Pancioli
Steve Mills on sun 24 jun 12
Dear Diana,
Referring back to my previous post on this, you state the setting area is 3=
5=3D
Cu Ft, what is the gross capacity going to be.=3D20
My last production kiln was 30 Cu Ft setting area, 55 Cu Ft gross. The two =
n=3D
aturally aspirated burners were 400 btu each. I had up to 10 ins WC availab=
l=3D
e to me, only used 6 ins max. =3D46rom what I've learnt, you will probably =
hav=3D
e more available to you.=3D20
If your gross volume is no more than 60, I think you will be fine with thos=
e=3D
burners you've found.=3D20
Go for it
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my iPod
On 23 Jun 2012, at 19:46, dianamp@COMCAST.NET wrote:
> Hi again:
>=3D20
>=3D20
> These are questions about the same catenary kiln (about 35 cu. ft. load) =
m=3D
ade of IFB,
> that I asked about a few weeks ago.
>=3D20
>=3D20
> We have found some very nice burners that each put out 375,000 BTU's.
> Which means that two of them at max would put out about 3/4 of a million
> BTU's. I built kilns this size before with more and smaller burners and m=
o=3D
re total power--
> a million BTU's, but never used that million, ever.
>=3D20
>=3D20
> So, do you think there is anything wrong with two natural gas burners tha=
t=3D
big
> for a kiln that size, one on each side running parallel to the sides of t=
h=3D
e kiln,
> flame inside the bag walls, but in opposite directions.
>=3D20
>=3D20
> They would not need blowers--are high quality cast iron
> inspirating type with flame retention nozzles. Not home made.
>=3D20
>=3D20
> The gas meter can be moved to within a few feet of the kiln.
> Do you have any idea what water column pressure would be needed,
> if we do use them? I never did learn how to figure out WC Pressure.
>=3D20
>=3D20
> Thanks for any advice.
>=3D20
>=3D20
> Sincerely,
>=3D20
>=3D20
> Diana Pancioli
Eric Ciup on sun 24 jun 12
While I won't dispute that you built a marvolously even firing kiln with
opposed burners,I don't think you can ascribe it to the Coriolus effect.
This force, while quite powerful on planetary scales, is fairly
difficult to show in the laboratory. Contrary to popular belief toilets
do not run clockwise south of the equator and counter clockwise to the
north.
I realize that the firing channels are the same length but with opposed
burners one burner faces towards the flue and one away from it . I was
talking about the flame path, not the flue channels. One path would be
up and across to the flue wall, down and out while the other would be up
and across to the front wall, back and down to the flue wall, and out, a
one third difference in length. I don't think you would see a coherent
vortex flame path unless you built a circular kiln with a central flue.
> Having owned and fired kilns with the burners set up both ways, I much pr=
efer opposed burners, provided (underline that) they are set up to fire ant=
i-clockwise (Coriolis Effect, Northern Hemispher). That way the heat circul=
ates rapidly upwards before coming down through the setting. My last produc=
tion kiln was set up that way and fired completely even, front to back, top=
to bottom, side to side.
>
> Just what the Doctor ordered.
>
> The fire channels for both burners were the same length.
> Methinks you had a slightly odd shaped kiln to have one shorter than the =
other!
Steve Mills on sun 24 jun 12
Having owned and fired kilns with the burners set up both ways, I much pref=
e=3D
r opposed burners, provided (underline that) they are set up to fire anti-c=
l=3D
ockwise (Coriolis Effect, Northern Hemispher). That way the heat circulates=
r=3D
apidly upwards before coming down through the setting. My last production k=
i=3D
ln was set up that way and fired completely even, front to back, top to bot=
t=3D
om, side to side.
Just what the Doctor ordered.=3D20
The fire channels for both burners were the same length.=3D20
Methinks you had a slightly odd shaped kiln to have one shorter than the ot=
h=3D
er!
:-)
Steve M
Steve Mills
Bath
UK
www.mudslinger.me.uk
Sent from my iPod
On 23 Jun 2012, at 21:40, Eric Ciup wrote:
> I have two points to make. First, when using 2 burners in a downdraft
> kiln I place them on either side of the chimney so that the flame path
> is as long as possible before reaching the flue. The way you propose to
> do it you would have one burner with a long flame path and one with a
> much shorter path. This could lead to uneven heating from side to side
> although the turbulent atmosphere will probably even things out. The
> plumbing of two burners on one side would be more straightforward than
> kitty-corner burners.
> Secondly make sure your meter can supply you with the needed gas. I
> once had a studio that had an industrial sized meter that we had to pay
> rent on. To save money we switched it out for a residential sized meter
> which was rent free but it was only barely able to supply enough gas to
> fire our kiln in 12 hours. After I left the studio, they rebuilt the
> kiln as a sprung arch instead of a flat top and the firings took 2 to 3
> days to reach cone 9.
>=3D20
> Eric
shane mickey on mon 25 jun 12
Diana
=3DC2=3DA0
You will need to know your orfice size before you can know what btu's you c=
a=3D
n expect from a set pressure.
This is where people get into trouble. someone sells burners stating i get =
t=3D
his btu. If they tell you the pressure
and gas type then you can match that and expect the same btu's.
You state natural gas. were these burners used with natural gas before? It =
i=3D
s kinda uncommon to find natural gas
venturi (natural aspiration)=3DC2=3DA0 burners. This is a fairly big kiln f=
or lo=3D
w pressure
natural gas. Look at marc ward's site wardburnersystems, he has charts and =
c=3D
alculations to help you figure if you will have the right
btu's from the pressure you will have. Putting the meter close is a good id=
e=3D
a. Natural gas drops quickly based on
distance and number of turns!
If i had to guess on what N.G. pressure you would need it would be not in w=
a=3D
ter columns but more like pounds.
a venturi B5 at=3DC2=3DA0 7" only produces 81,000 btu's and that is a big o=
l bur=3D
ner,21 inches long!=3DC2=3DA0 so i would think more like
3 pounds.
I will with hold comments on burner orientation. i have seen both ways work=
.=3D
shane
http://www.shanemickeypotterslife.blogspot.com/
| |
|
