controlling gas jets
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I'm trying to build a robotic marshmallow griller. Don't ask why [noparse];)[/noparse].
I'd like the fire to be provided by a gas jet, like the kind you find
on a butane torch. Does anyone know of a way of controlling the flow
of gas using a basic stamp? Some kind of electronically controlled
valve?
I realize this is out of left field but I thought some of you
industrial control geniuses might have some suggestions...
Thanks!
I'd like the fire to be provided by a gas jet, like the kind you find
on a butane torch. Does anyone know of a way of controlling the flow
of gas using a basic stamp? Some kind of electronically controlled
valve?
I realize this is out of left field but I thought some of you
industrial control geniuses might have some suggestions...
Thanks!
Comments
leroy
markallen wrote:
>
> I'm trying to build a robotic marshmallow griller. Don't ask why [noparse];)[/noparse].
> I'd like the fire to be provided by a gas jet, like the kind you find
> on a butane torch. Does anyone know of a way of controlling the flow
> of gas using a basic stamp? Some kind of electronically controlled
> valve?
>
> I realize this is out of left field but I thought some of you
> industrial control geniuses might have some suggestions...
>
> Thanks!
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
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the flame rather than the flame size. This way you don't have to worry
about calibrating a value, how much is too much, how much is too little,
etc.
Nathan
Original Message
From: Leroy Hall [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=j228lt0sYi68XJg5652qZMSb_HYk9mV5DDICkLp5BQ2f47d7jnDBF_T6xjMRu82qhf1G-FVgkmm4]leroy@f...[/url
Sent: Sunday, November 18, 2001 4:38 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] controlling gas jets
A gas furnace does a nice job of this?
leroy
markallen wrote:
>
> I'm trying to build a robotic marshmallow griller. Don't ask why [noparse];)[/noparse].
> I'd like the fire to be provided by a gas jet, like the kind you find
> on a butane torch. Does anyone know of a way of controlling the flow
> of gas using a basic stamp? Some kind of electronically controlled
> valve?
>
> I realize this is out of left field but I thought some of you
> industrial control geniuses might have some suggestions...
>
> Thanks!
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
Your use of Yahoo! Groups is subject to
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>the flame rather than the flame size. This way you don't have to worry
>about calibrating a value, how much is too much, how much is too little,
>etc.
It would be easier, but the visual look of the flames getting bigger
and smaller is part of the piece
1. Use a solenoid valve
2. Use a regular valve w/servo
Servo would probably be the way to go. They're relatively cheap
(~$10-$15) and easy to control, requiring only a PWM signal. I
haven't done anything with solenoid valves yet (in fact I don't even
have any) but I believe you need to use some sort of driving system,
be it MOSFETs or a driver chip. For a servo method, you could
probably get a valve designed for fish tank air tubes, and put a
servo arm on top. Then you could just hook the servo up to the Stamp
and send it PWM. No calibration would be needed, because servos
have their own calibration/positioning components.
measure you also need to include some sort of flame detection so
the gas can be shut off if there's a flame out.
As far as regulating the gas goes a motor driven valve is obvious
or possible a solenoid operated valve that is operated linearly
by pulse width modulating it. You may also need to incorporate
some sort of feedback in the form of flow measurement, etc.
Sounds like an expensive marshmallow roaster, but an interesting
project.
Tim
> >It might be much easier to control the distance from the
marshmallow to
> >the flame rather than the flame size. This way you don't have
to worry
> >about calibrating a value, how much is too much, how much is
too little,
> >etc.
>
> It would be easier, but the visual look of the flames getting
bigger
> and smaller is part of the piece
fixed height. You could vary the speed to adjust the cooking speed and
rotate the marshmallow as you moved it across the flame to make sure all the
sides are done.
Original Message
> If you are actually controlling the flame then as a safety
> measure you also need to include some sort of flame detection so
> the gas can be shut off if there's a flame out.
>
> As far as regulating the gas goes a motor driven valve is obvious
> or possible a solenoid operated valve that is operated linearly
> by pulse width modulating it. You may also need to incorporate
> some sort of feedback in the form of flow measurement, etc.
>
> Sounds like an expensive marshmallow roaster, but an interesting
> project.
valve has pulled open there should be range of pulsing (or pulse
looping) via FET that could operate it in an area at part throttle.
Grinding a bit of the valve spring (reducing spring tension) should
increase the range this is feasible in and reduce the noise somewhat.
It would then operate more like a speaker voice coil. If you do modify
spring tension I would definitely use a shutoff valve in the gas line
train.
As solenoids (like relays) have both a pull in voltage and a holding
voltage it would be best for the voltage to be at the pull in rating or
higher. It could work using a tad of negative logic. By this I mean in
lieu of controlling it's ON time controlling its OFF time. The
advantage would be that while sensing other devices such as a thermistor
or photocell the flame would not go out. The flame should, ever so
briefly, elongate then shrink.
This would require a manual restricting valve (like the stove top
variety) to adjust for maximum flame size. Photocells (the kind that
vary resistance) can be used to judge the condition of the marshmallow
and additionally serve as your safety system of sensing if the flame has
indeed gone out.
Initial ignition can be done by pulsing a motorcycle ignition coil to
fire a spark plug or other spark gap device.
On the other foot it would be infinitely cheaper to FET pulse some
nichrome wire to glow and read the reflected light by photocell to avoid
making crispy critters.
markallen wrote:
>
> I'm trying to build a robotic marshmallow griller. Don't ask why [noparse];)[/noparse].
> I'd like the fire to be provided by a gas jet, like the kind you find
> on a butane torch. Does anyone know of a way of controlling the flow
> of gas using a basic stamp? Some kind of electronically controlled
> valve?
>
> I realize this is out of left field but I thought some of you
> industrial control geniuses might have some suggestions...
>
> Thanks!
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
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share something I cooked up last night with the rest of you bachelors
that tire of hot dogs and/or peanut butter sandwiches.
Glop a package of boneless chicken into a frying pan. Add a can of
mandarin oranges with the packing syrup. Sprinkle soy sauce on the
chicken. Simmer for 20 minutes turning every 5 min or so.
Great pseudo chinese dish.
Don Denhardt wrote:
>
> A solenoid valve might be used as a sort of modulating valve. Once the
> valve has pulled open there should be range of pulsing (or pulse
> looping) via FET that could operate it in an area at part throttle.
> Grinding a bit of the valve spring (reducing spring tension) should
> increase the range this is feasible in and reduce the noise somewhat.
> It would then operate more like a speaker voice coil. If you do modify
> spring tension I would definitely use a shutoff valve in the gas line
> train.
>
> As solenoids (like relays) have both a pull in voltage and a holding
> voltage it would be best for the voltage to be at the pull in rating or
> higher. It could work using a tad of negative logic. By this I mean in
> lieu of controlling it's ON time controlling its OFF time. The
> advantage would be that while sensing other devices such as a thermistor
> or photocell the flame would not go out. The flame should, ever so
> briefly, elongate then shrink.
>
> This would require a manual restricting valve (like the stove top
> variety) to adjust for maximum flame size. Photocells (the kind that
> vary resistance) can be used to judge the condition of the marshmallow
> and additionally serve as your safety system of sensing if the flame has
> indeed gone out.
>
> Initial ignition can be done by pulsing a motorcycle ignition coil to
> fire a spark plug or other spark gap device.
>
> On the other foot it would be infinitely cheaper to FET pulse some
> nichrome wire to glow and read the reflected light by photocell to avoid
> making crispy critters.
>
> markallen wrote:
> >
> > I'm trying to build a robotic marshmallow griller. Don't ask why [noparse];)[/noparse].
> > I'd like the fire to be provided by a gas jet, like the kind you find
> > on a butane torch. Does anyone know of a way of controlling the flow
> > of gas using a basic stamp? Some kind of electronically controlled
> > valve?
> >
> > I realize this is out of left field but I thought some of you
> > industrial control geniuses might have some suggestions...
> >
> > Thanks!
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
> _________________________________________________________
> Do You Yahoo!?
> Get your free @yahoo.com address at http://mail.yahoo.com
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
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Some sort of flame detection does need to be done. A temp sensor or
thermocouple in the flame.
On commercial flame cutting machines the gas levels are adjusted with
separate valves and switched in/out with solenoids. They use 3 set levels so
3 valve/solenoics are used. Just switch the solenoids at the proper time.
Make sure all gas fittings are tight without leaks. Even small leaks can make
big flames.
I do use Stamps to control these machines. The Solenoids we use are rated for
flammable gas and are about $100 each. The regulated control valves are about
$300 each. You cant use straight valves as when the gas pressure changes the
size of the flame will also change. Big flame with full tank and smaller
flames as the tank runs out.
Good Luck and Be Safe.
Alan Bradford
its $50 though.
Original Message
> AND speaking of marshmallows got me thinking about food. I thought I'd
> share something I cooked up last night with the rest of you bachelors
> that tire of hot dogs and/or peanut butter sandwiches.
>
> Glop a package of boneless chicken into a frying pan. Add a can of
> mandarin oranges with the packing syrup. Sprinkle soy sauce on the
> chicken. Simmer for 20 minutes turning every 5 min or so.