[Clayart] orifices

mel jacobson melpots2 at visi.com
Wed Oct 5 07:29:11 EDT 2016

so much depends on what sort of gas pressure you have.
commercial pressure coming into a school, university or 
business can be has high as 10 inches of water column.
(google inches of water column and understand how gas is 
measured. as i said the other day, we talk pounds, 
ounces,water column....and most have no clue as to what they 
have. that is why talking on the net or the phone can be 
hard...we just don't know...often we can hear with our 
ears...it is not right.)

a home may have less than two inches of water column.

if your pressure is low, and not a great flow of gas, you 
may need to increase the size of your orifice to match it.

we don't know what sumi has to her kiln. it may be low and 
the natural gas orifices may help make up the difference.
a quality heating expert can measure all the pressures. 
they have tools to do that.

at my studio i run an underground 1.5 inch black pipe system 
to my basement where it is T'd into my home gas system. it 
is 50 feet...so, the pressure is getting pretty low at my 
kiln. i have what i have...and it works just fine.  and, as 
i tell people in my book, you too may have `just enough 
gas`.  it costs me next to nothing to fire my kiln. when 
propane hit 6 bucks a gallon a few years back...potters quit 
firing.  (in many cases they learned to understand what they 
were doing and made adjustments to save fuel. that was a 
good thing. both nils and mel smiled as people changed what 
they were doing, and came on board to new and better ways of 
firing kilns.)  crow meat was available.

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