John Rodgers on tue 10 feb 04
Yarrgh!! Computers - love'em/ hate'em!
I just wrote to you what I was doing, and offered a solution for you, --
all quite lengthy -- and the made a spastic poke at a wrong key and
succeeded in disappearing the entire thing.!!!
There are a number of industrial valves that use calibrated orifices,
and this is where you want to go. Some are operated by raising a cone
valve up and down over an opening in the valve, and a solenoid is used
to control the opening and closing. Others use a lever on the valve
which is driven by a control device like a pneumatic controller, which
is a bellows like device that expands and contracts moving the valve
arm, and another type is a valve with a circular gear on the end of the
shaft, coupled to a worm drive mounted on the shaft of a controllable
motor like a stepping motor which comes from a CAD controlled machinest
lathe. CNC as it were.
Just a few suggestions as to where to investigate.
I have been working on a homebuilt controller, but haven't made much
progress. My approach is to write a program to run on my desktop PC.
Connect the PC via a parallel cable to the little controll box I
propose to build, and let it regulate the power to the kiln. I'm sure
this will work.
Any sharing or info, or any input you may have on my project would be
appreciated.
I hope eventually to release my parts and materials list, schematics,
and my program (or at least the code) to Clayart for those who like to
do the homebuilts thing.
Regards,
John Rodgers
Chelsea, AL
ian wrote:
>I built an electronically controller for my electric kiln using a
commercially available Bartlett circuit board. I have now proven to myself
that the rate at which the kiln is cooled changes the appearance of the
glaze more than altering the ingredients. One glaze - which yielded a
glossy, brown surface when cooled quickly - produced a satiny, gray surface
with brick-red speckles when cooled slowly!
>
>I now wish to apply the same principle to the gas kiln available to me.
This kiln is small, and, thus, cools quickly. If I could regulate the gas
supply with a electrically-activated valve, I could adapt my breadboarded
controller to the gas kiln. Simply turning down the gas incrementally does
not yield the same result. When the gas is turned down, the temperature
initially falls quickly, then approaches a plateau assymptotically. Turning
down the gas at intervals produces a very uneven cooling curve.
>
>Does anyone have any experience with this?
>
>___________________________________________________________________________
___
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
>
>
John Rodgers on wed 11 feb 04
Wayne, interesting questions.
Lots of things to work through, but not to worry. The saety side is
definitely going to be addressed on my part.
Nils Lou once built a burner system for me. It was electrically
controlled from a panel. There was a main gas flow valve with solenoid
shutoff, there were secondary gas flow valves for each burner - with
solenoid shutoff valves, there was a central squirrel cage blower, with
variable control, there were electric igniters to light the pilot lights
and UV sensors wired in to sense pilot light operation. When ignition
occured and the sensors picked up the UV from the pilot lights, then the
electric solenoid valves would open and allow the gas to flow. If in the
event of a power outage, the solenoids would shut down the system. It
would not restart unless a manual reset was initiated. The only way the
gas could flow was if a re-ignition sequence was manually activated, to
get UV from the pilot light. Then and only then could the gas valves
open and re-ingnition occur. All of these parameters could be controlled
safely controlled by a computer.
Regards,
John Rodgers
Chelsea, AL
wayneinkeywest wrote:
>Sorry for the long return below, but it is all pertinent.
>Having been involved in computer control
>(marrying PCs to CNC/laser cutting equipment in
>the past, I have only one question...
>
>Varying the gas flow is fine. There are any number of
>flow control valves out there that will work just fine.
>Calibration to cone settings is going to take some time
>but that's the nature of the beast.
>
>Question is what you are going to use / how you are
>going to ignite the burner.
>
>Does the controller circuit have sufficient power output
>(maybe through a slave relay?) to trigger a
>piezo-electric igniter or set of igniters?
>
>Are you going to resort to/ bypass/ incorporate a Baso valve? Use
>an
>existing flame always on pilot light? You need to think about
>the consequences of turning the regulation of your gas flow
>over to the machine. No, I DO NOT want to get into that discussion
>since i believe in machines ability to make our lives easier, when
>they work according to parameters.
>
>Should the pressure in the tank drop too
>low, or the 'puter decide to reduce the flow to a level below
>that which will maintain ignition in the burner (or a high wind
>comes along and blows the flame out (think worst-case
>scenario here) is the control circuit (PC) going to recognize that,
>or
>being heat dependent, decide to open the valve up to
>compensate for lower kiln temperatures, letting raw gas flow freely?
>Seen THAT happen before....sent a furnace out through the roof
>of a three story building, landed a block away in someone's
>kitchen and killed her.
>
>Please don't think I'm nit-picking. I love the idea, and am
>silently
>cheering that it may actually be possible to control gas appliances
>with a PC. Just please think about writing a safety protocol into
>the
>programming.
>
>Wayne Seidl
>
>
>
>
>
>
>>Yarrgh!! Computers - love'em/ hate'em!
>>
>>I just wrote to you what I was doing, and offered a solution for
>>
>>
>you, --
>
>
>>all quite lengthy -- and the made a spastic poke at a wrong key
>>
>>
>and
>
>
>>succeeded in disappearing the entire thing.!!!
>>
>>There are a number of industrial valves that use calibrated
>>
>>
>orifices,
>
>
>>and this is where you want to go. Some are operated by raising a
>>
>>
>cone
>
>
>>valve up and down over an opening in the valve, and a solenoid is
>>
>>
>used
>
>
>>to control the opening and closing. Others use a lever on the
>>
>>
>valve
>
>
>>which is driven by a control device like a pneumatic controller,
>>
>>
>which
>
>
>>is a bellows like device that expands and contracts moving the
>>
>>
>valve
>
>
>>arm, and another type is a valve with a circular gear on the end
>>
>>
>of the
>
>
>>shaft, coupled to a worm drive mounted on the shaft of a
>>
>>
>controllable
>
>
>>motor like a stepping motor which comes from a CAD controlled
>>
>>
>machinest
>
>
>>lathe. CNC as it were.
>>
>>Just a few suggestions as to where to investigate.
>>
>>I have been working on a homebuilt controller, but haven't made
>>
>>
>much
>
>
>>progress. My approach is to write a program to run on my desktop
>>
>>
>PC.
>
>
>>Connect the PC via a parallel cable to the little controll box I
>>propose to build, and let it regulate the power to the kiln. I'm
>>
>>
>sure
>
>
>>this will work.
>>
>>Any sharing or info, or any input you may have on my project
>>
>>
>would be
>
>
>>appreciated.
>>
>>I hope eventually to release my parts and materials list,
>>
>>
>schematics,
>
>
>>and my program (or at least the code) to Clayart for those who
>>
>>
>like to
>
>
>>do the homebuilts thing.
>>
>>
>snip:
>
>
>>>I built an electronically controller for my electric kiln using a
>>>
>>>
>commercially available Bartlett circuit board. I have now proven to
>myself that the rate at which the kiln is cooled changes the
>appearance of the glaze more than altering the ingredients. One
>glaze - which yielded a glossy, brown surface when cooled quickly -
>produced a satiny, gray surface with brick-red speckles when cooled
>slowly!
>
>
>>>I now wish to apply the same principle to the gas kiln available
>>>
>>>
>to me. This kiln is small, and, thus, cools quickly. If I could
>regulate the gas supply with a electrically-activated valve, I could
>adapt my breadboarded controller to the gas kiln. Simply turning
>down the gas incrementally does not yield the same result. When the
>gas is turned down, the temperature initially falls quickly, then
>approaches a plateau assymptotically. Turning down the gas at
>intervals produces a very uneven cooling curve.
>
>
>>>Does anyone have any experience with this?
>>>
>>>
>>>
>>___________________________________________________________________
>>
>>
>___________
>
>
>>>Send postings to clayart@lsv.ceramics.org
>>>
>>>You may look at the archives for the list or change your
>>>
>>>
>subscription
>
>
>>>settings from http://www.ceramics.org/clayart/
>>>
>>>Moderator of the list is Mel Jacobson who may be reached at
>>>
>>>
>melpots@pclink.com.
>
>
>>>
>>>
>>>
>>
>>
>____________________________________________________________________
>__________
>
>
>>Send postings to clayart@lsv.ceramics.org
>>
>>You may look at the archives for the list or change your
>>
>>
>subscription
>
>
>>settings from http://www.ceramics.org/clayart/
>>
>>Moderator of the list is Mel Jacobson who may be reached at
>>
>>
>melpots@pclink.com.
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
>
>
>
wayneinkeywest on wed 11 feb 04
Sorry for the long return below, but it is all pertinent.
Having been involved in computer control
(marrying PCs to CNC/laser cutting equipment in
the past, I have only one question...
Varying the gas flow is fine. There are any number of
flow control valves out there that will work just fine.
Calibration to cone settings is going to take some time
but that's the nature of the beast.
Question is what you are going to use / how you are
going to ignite the burner.
Does the controller circuit have sufficient power output
(maybe through a slave relay?) to trigger a
piezo-electric igniter or set of igniters?
Are you going to resort to/ bypass/ incorporate a Baso valve? Use
an
existing flame always on pilot light? You need to think about
the consequences of turning the regulation of your gas flow
over to the machine. No, I DO NOT want to get into that discussion
since i believe in machines ability to make our lives easier, when
they work according to parameters.
Should the pressure in the tank drop too
low, or the 'puter decide to reduce the flow to a level below
that which will maintain ignition in the burner (or a high wind
comes along and blows the flame out (think worst-case
scenario here) is the control circuit (PC) going to recognize that,
or
being heat dependent, decide to open the valve up to
compensate for lower kiln temperatures, letting raw gas flow freely?
Seen THAT happen before....sent a furnace out through the roof
of a three story building, landed a block away in someone's
kitchen and killed her.
Please don't think I'm nit-picking. I love the idea, and am
silently
cheering that it may actually be possible to control gas appliances
with a PC. Just please think about writing a safety protocol into
the
programming.
Wayne Seidl
> Yarrgh!! Computers - love'em/ hate'em!
>
> I just wrote to you what I was doing, and offered a solution for
you, --
> all quite lengthy -- and the made a spastic poke at a wrong key
and
> succeeded in disappearing the entire thing.!!!
>
> There are a number of industrial valves that use calibrated
orifices,
> and this is where you want to go. Some are operated by raising a
cone
> valve up and down over an opening in the valve, and a solenoid is
used
> to control the opening and closing. Others use a lever on the
valve
> which is driven by a control device like a pneumatic controller,
which
> is a bellows like device that expands and contracts moving the
valve
> arm, and another type is a valve with a circular gear on the end
of the
> shaft, coupled to a worm drive mounted on the shaft of a
controllable
> motor like a stepping motor which comes from a CAD controlled
machinest
> lathe. CNC as it were.
>
> Just a few suggestions as to where to investigate.
>
> I have been working on a homebuilt controller, but haven't made
much
> progress. My approach is to write a program to run on my desktop
PC.
> Connect the PC via a parallel cable to the little controll box I
> propose to build, and let it regulate the power to the kiln. I'm
sure
> this will work.
>
> Any sharing or info, or any input you may have on my project
would be
> appreciated.
>
> I hope eventually to release my parts and materials list,
schematics,
> and my program (or at least the code) to Clayart for those who
like to
> do the homebuilts thing.
snip:
>
> >I built an electronically controller for my electric kiln using a
commercially available Bartlett circuit board. I have now proven to
myself that the rate at which the kiln is cooled changes the
appearance of the glaze more than altering the ingredients. One
glaze - which yielded a glossy, brown surface when cooled quickly -
produced a satiny, gray surface with brick-red speckles when cooled
slowly!
> >
> >I now wish to apply the same principle to the gas kiln available
to me. This kiln is small, and, thus, cools quickly. If I could
regulate the gas supply with a electrically-activated valve, I could
adapt my breadboarded controller to the gas kiln. Simply turning
down the gas incrementally does not yield the same result. When the
gas is turned down, the temperature initially falls quickly, then
approaches a plateau assymptotically. Turning down the gas at
intervals produces a very uneven cooling curve.
> >
> >Does anyone have any experience with this?
> >
>
>___________________________________________________________________
___________
> >Send postings to clayart@lsv.ceramics.org
> >
> >You may look at the archives for the list or change your
subscription
> >settings from http://www.ceramics.org/clayart/
> >
> >Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
> >
> >
> >
>
>
____________________________________________________________________
__________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your
subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
| |
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