Ivor and Olive Lewis on tue 13 dec 05
Dear Friends,
I am seeking information about the pressure exerted by the vacuum pumps =
of the pug mills you are using. There must be a few since we appear to =
number +++2000 and many of you must have access to them in schools or =
colleges.
I have information from one of the manufacturers expressed a negative =
kilopascals. If your gauges are in PSI or some other scale do not worry, =
I should be able to do the conversions.
Pascals pressure by the way is Force in Newtons per Square Metre.
It may be that no one has ever thought to analyse the exhaust from a pug =
mill. Would it be useful knowledge ?. To any one else possibly not. But =
to me it could be enlightening.
Thanks in advance.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
skiasonaranthropos@FSMAIL.NET on tue 13 dec 05
Hello Ivor,
All the pugs Ive worked with have had mounted vacuum gauges, and some with
systems that either sound an alarm or stop extrusion below a pre set
minimum that's typically at least 27.5 inches Hg
Regards,
Antony
Bruce Girrell on tue 13 dec 05
> I am seeking information about the pressure exerted by the vacuum pumps
> of the pug mills you are using.
Ivor,
The Peter Pugger VPM-30 normally pulls to 25 inches. It uses a diaphragm
type vacuum pump. I have rigged an auxiliary vacuum pump and have pulled it
to 28 inches.
I think that you may have mentioned this before but, aside from water vapor,
what do you expect to find in the pump output and what would that tell you?
Bruce "I'll bite" Girrell
Paul Herman on tue 13 dec 05
Greetings Ivor,
With the pugmill I use (a Peter Pugger) the manufacturer recommends
that you get the vacuum above 21 inches Hg. It usually goes up to 24
or 25, then I empty the machine.
Best,
Paul Herman
Great Basin Pottery
Doyle, California US
http://greatbasinpottery.com
On Dec 12, 2005, at 9:10 PM, Ivor and Olive Lewis wrote:
> Dear Friends,
> I am seeking information about the pressure exerted by the vacuum
> pumps of the pug mills you are using. There must be a few since we
> appear to number +++2000 and many of you must have access to them
> in schools or colleges.
> I have information from one of the manufacturers expressed a
> negative kilopascals. If your gauges are in PSI or some other scale
> do not worry, I should be able to do the conversions.
> Pascals pressure by the way is Force in Newtons per Square Metre.
> It may be that no one has ever thought to analyse the exhaust from
> a pug mill. Would it be useful knowledge ?. To any one else
> possibly not. But to me it could be enlightening.
> Thanks in advance.
> Best regards,
> Ivor Lewis.
> Redhill,
> South Australia.
Pfeiffer, Dan R (Dan) on tue 13 dec 05
Greetings Ivor,
With the pugmill we use (Axnor's new wave) the manufacturer recommends
that you get the vacuum above 25 inches Hg. We try for 25 - 30 and have
little trouble keeping it there.
Dan & Laurel in Elkmont Al
Pfeiffer Fire Arts
Potters Council Members
Craig Martell on tue 13 dec 05
Hello Ivor:
I use a Venco 4" mill to deair various porcelain bodies. Depending on clay
consistency and my effieciency in loading and pugging, the vacuum is
usually 90 to 95 KPa. The vacuum pump is a Clisby 500 Series if that's of
any concern.
regards, Craig Martell Hopewell, Oregon
Vince Pitelka on tue 13 dec 05
> All the pugs Ive worked with have had mounted vacuum gauges, and some with
> systems that either sound an alarm or stop extrusion below a pre set
> minimum that's typically at least 27.5 inches Hg
My experience corresponds with Antony's. Harry Davis recommended 26-28 Hg
of vacuum in his pugmill plans, and of course all the single-shaft de-airing
mills (Venco, Bluebird, etc.) are based on the Harry Davis design.
- 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/
Ivor and Olive Lewis on thu 15 dec 05
Dear Bruce Girrell ,
In other words, the readings for the Peter Puggier, as a commercial =
unit, is minus twenty five inches. If you go down to minus 28 inches =
with the additional pump this would be significant. Do you confirm my =
hypothesis that this extra pull would enhance the throwing quality of =
your clay. Was this in Summer or Winter?
What might one find. As you say, water vapour. How about carbon dioxide =
from all that bacterial decomposition? Could even be a different oxygen =
to nitrogen ratio !
Is this discharge significant ? Who knows ? Importantly, why has the =
question not been asked before?
Is the "bait" sweet.
All the best,
Ivor
Ivor and Olive Lewis on thu 15 dec 05
Dear Paul Herman,=20
Thank you for your information.
I am reading the "inch Hg" values sent to me as Negative values, =
otherwise the air would be no thinner than that at the top of a 10000 ft =
mountain.
All the best,
Ivor
Ivor and Olive Lewis on thu 15 dec 05
<with
systems that either sound an alarm or stop extrusion below a pre set =
minimum that's typically at least 27.5 inches Hg>>
Dear Antony,
I take it that you mean Minus 27.5 inches Hg
Thanks for the information.
Best regards,
Ivor
Ivor and Olive Lewis on thu 15 dec 05
Dear Craig Martell=20
Yes, it certainly is. Though, as I have been saying about the measure in =
inches Hg, that the value is Negative, measured downward from 101 kPa, =
760 mm Hg or 29 inches Hg.
Clisby is a South Australian Company who manufacture pneumatic =
equipment. Small World.
Enjoy the festive season and thanks for the info.
Best regards,
Ivor
skiasonaranthropos@FSMAIL.NET on thu 15 dec 05
Hello Ivor,
You asked =93Do you confirm my hypothesis that this extra pull would enhance=
the throwing quality of your clay=94 ... yes its a well recognised
phenomenon; and one reason why pugs have recommended minimum vacuum levels
and even alarms or cut outs
Regards,
Antony
Pfeiffer, Dan R (Dan) on thu 15 dec 05
Leave it to Ivor to want us to really understand what the numbers mean! I
just read the gage, bigger number more vacuum. In reading the fine print
it also has kPa on the inside ring and hg on the outside. In reading about
vacuum pumps I am thinking the oil used may be a source of vapor that could
used to be vented outside, but than the pump does not run all that long
anyway. I can pug a lot of clay in a few hours.
One thing I did read is it is better to leave the pump running all the time
and dump the vacuum with a valve if you need to do some short thing. The
idea being every time the pump stops it draws air back into the pump pulling
with it any water or other gunk that was moving out.
-
>>>I am reading the "inch Hg" values sent to me as Negative values,
otherwise the air would be no thinner than that at the top of a 10000 ft
mountain.>>>
Dan & Laurel in Elkmont Al
Pfeiffer Fire Arts
Potters Council Members
BJ Clark | Stinking Desert Ceramics on thu 15 dec 05
Ivor,
I believe our 4" (that's the 1lb per inch model, yes?) Venco usually reads
-80 (kPa I believe). And we are at about 5000ft elevation.
Don't know if it's the original pump.
Hope that helps,
BJ Clark
On 12/12/05, Ivor and Olive Lewis wrote:
>
> Dear Friends,
> I am seeking information about the pressure exerted by the vacuum pumps o=
f
> the pug mills you are using. There must be a few since we appear to numbe=
r
> +++2000 and many of you must have access to them in schools or colleges.
> I have information from one of the manufacturers expressed a negative
> kilopascals. If your gauges are in PSI or some other scale do not worry, =
I
> should be able to do the conversions.
> Pascals pressure by the way is Force in Newtons per Square Metre.
> It may be that no one has ever thought to analyse the exhaust from a pug
> mill. Would it be useful knowledge ?. To any one else possibly not. But t=
o
> me it could be enlightening.
> Thanks in advance.
> Best regards,
> Ivor Lewis.
> Redhill,
> South Australia.
>
>
> _________________________________________________________________________=
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> melpots@pclink.com.
>
--
BJ Clark
Stinking Desert Ceramics
bjclark@stinkingdesert.com
www.stinkingdesert.com
Ivor and Olive Lewis on fri 16 dec 05
Dear Bonnie,=20
If you are 8800 feet above sea level you will never get to a reading of =
25 inches, I would imagine your reading of 18 inches, when corrected to =
Sea Level would be equal to or better than P.Ps recommendations.
Other folk who are up in the Mountains or High Plains should bear this =
in mind. ( I forgot to correct for topographic elevation on a training =
flight from Winnepeg to Edmonton and landed 300 feet underground ! ! =
Fortunately the pilot ignored my lack of direction and instruction. So =
we survived)
The main thing is that you get great clay out of the machine.
Best wishes to you for the festive season,
Ivor
Ivor and Olive Lewis on fri 23 dec 05
Dear Friends,
I wish you all a very happy celebrations during the Festive Season and =
an Interesting Two Double "0" Six. I value your friendship and =
companionship.=20
Thank you to all those people who assisted me with figures for the =
pressures indicated on De-Airing Pug Mill Gauges. Quite enlightening !
It would seem as though no one has ever made quantitative and =
qualitative analyses of gases drawn from clay in the De-airing process. =
Guesswork suggests it will contain Air, possibly Carbon dioxide and a =
quantity of Water Vapour. The composition will depend on the amount of =
air trapped in the system, the degree of decomposition of organic =
inclusions and other factors. With regards to Water, the quantity =
exhausted will depend on several factors; Altitude, Ambient Temperature, =
Atmospheric Pressure and Pug Mill Chamber Pressure.
My own opinion it is water that is the most important of these.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Earl Brunner on fri 23 dec 05
LOL!!!
Ivor, it is refreshing to see you stating something in terms of it being your opinion!!!!!!!
Could you provide scientific data to back that up? LOL!!!!
Just kidding.
But I really never expected to see that sentence from you of all people.
Earl Brunner e-mail: brunv53@yahoo.com
----- Original Message ----
From: Ivor and Olive Lewis
To: CLAYART@LSV.CERAMICS.ORG
Sent: Thursday, December 22, 2005 9:06:40 PM
Subject: Pug Mill Information
My own opinion it is water that is the most important of these.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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