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Re: [hobbicast] Re: 20lb Propane tank and pressure?

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  • info.host@btinternet.com
    ... 2 tanks will solve the problem. Image you have a pan full of water, you put 100.C. under the pan and let it heat up. Then you take a wok or something
    Message 1 of 13 , Sep 1, 2001
      > 2 tanks
      > won't solve the problem,you get twice the same problem.Try running it
      > while warming up the tanks with hot water running over them
      > constantly.

      2 tanks will solve the problem. Image you have a pan full of water, you put
      100.C. under the pan and let it heat up. Then you take a wok or something
      similar, put the same amount of water in and heat to 100.C. The wok boils
      quicker. Inside the propane tank there is an area of liquid propane at
      pressure. Letting off the pressure boils the propane. If you have twice the
      surface area it boils twice as quickly, if you manifold two tanks together
      and open both AT THE SAME TIME, the area for the propane to boil on because
      twice the size. If you only use one tank there is a lot of propane trying to
      boil off a small surface which needs lots of energy. Two tanks, larger
      surface, energy spread out more. This is a recognised way of dealing with
      freezing up tanks. Dunking the tanks in warm water will work but the tanks
      loose heat very quickly when you're running a big burner off one alone, and
      if you have two, why not use two?

      Thanks,
      John Heritage
    • Ehkerr@aol.com
      In a message dated 9/1/2001 7:02:09 PM Eastern Daylight Time, ... John, to me is would appear that the ratio of surface area to liquid remains the same whether
      Message 2 of 13 , Sep 2, 2001
        In a message dated 9/1/2001 7:02:09 PM Eastern Daylight Time,
        info.host@... writes:


        > 2 tanks will solve the problem. Image you have a pan full of water, you put
        > 100.C. under the pan and let it heat up. Then you take a wok or something
        > similar, put the same amount of water in and heat to 100.C. The wok boils
        > quicker. Inside the propane tank there is an area of liquid propane at
        > pressure. Letting off the pressure boils the propane. If you have twice the
        > surface area it boils twice as quickly, if you manifold two tanks together
        > and open both AT THE SAME TIME, the area for the propane to boil on because
        > twice the size. If you only use one tank there is a lot of propane trying to
        > boil off a small surface which needs lots of energy. Two tanks, larger
        > surface, energy spread out more. This is a recognised way of dealing with
        > freezing up tanks. Dunking the tanks in warm water will work but the tanks
        > loose heat very quickly when you're running a big burner off one alone, and
        > if you have two, why not use two?
        >
        > Thanks,
        > John Heritage
        >

        John, to me is would appear that the ratio of surface area to liquid remains
        the same whether you have 2 tanks or a dozen tanks. As in math, equals added
        to equals are equal. Furthermore, 2 tanks were used and the problem
        persisted. Your discourse did not explain why 2 tanks did not solve the
        problem. Please elaborate.
        EKerr


        [Non-text portions of this message have been removed]
      • emovi@mweb.co.za
        Hello All ... EKerr, the thing to bear in mind is that the propane flow rate is fixed by the capacity of the burner. When you couple two propane tanks together
        Message 3 of 13 , Sep 2, 2001
          Hello All

          > John, to me is would appear that the ratio of surface area to liquid remains
          > the same whether you have 2 tanks or a dozen tanks. As in math, equals added
          > to equals are equal. Furthermore, 2 tanks were used and the problem
          > persisted. Your discourse did not explain why 2 tanks did not solve the
          > problem. Please elaborate.
          > EKerr


          EKerr, the thing to bear in mind is that the propane flow rate is fixed by the capacity of the burner. When you couple two propane tanks together you are boiling the propane off at half the rate in each tank and thus the cooling due to the latent heat of evaporation is also halved.

          If your problem seems to be independent on the number of tanks then I would start looking at the flow resistance in the feed lines, valves etc.

          Good luck - edi



          [Non-text portions of this message have been removed]
        • info.host@btinternet.com
          ... remains ... added ... As you increase surface area you decrease the amount of propane that must boil off one spot. If both tanks are opened at once they
          Message 4 of 13 , Sep 2, 2001
            > John, to me is would appear that the ratio of surface area to liquid
            remains
            > the same whether you have 2 tanks or a dozen tanks. As in math, equals
            added
            > to equals are equal. Furthermore, 2 tanks were used and the problem
            > persisted. Your discourse did not explain why 2 tanks did not solve the
            > problem. Please elaborate.
            > EKerr

            As you increase surface area you decrease the amount of propane that must
            boil off one spot. If both tanks are opened at once they shouldn't really be
            freezing too quickly. If you are renting the tanks, and two at once are
            freezing, get a smaller size and get three. The minute tanks begin to freeze
            pressure falls off quickly as the liquid can't get the energy it needs to
            evaporate, eventually (If it was super cool) it wouldn't evaporate anymore
            because it'd be too cold.

            The problem we are trying to avoid is the tank's shell needing so much heat
            on it that it is freezing itself trying to get it and more importantly, it's
            not getting the heat and pressure is falling off. Adding more tanks means
            less heat is needed to go into each tank, but overall the same amount is
            going in. Sputtering might be caused by the regulator's valve vibrating
            slightly when pressure is just high enough to hold it open. I expect there
            comes a point where the gas gets so cold that some of the vapour condenses
            again before burning. The size of the tank's surface area inside has been
            very carefully calculated otherwise they'd make tanks that look more like
            pancakes, there must be a reason for them not doing so. I can quote the
            'more tanks' idea from the BOC manual. One other cause of sputter is liquid
            propane getting to the burner, if you're running it with the tanks on their
            sides that is very likely. Try turning a propane tank upside down, you have
            an instant flame thrower.

            Thanks,
            John H.
          • Rupert Wenig
            Hello, My suspicions are that the propane in the bottles is freezing up. You could try warming them with water to help keep the pressure up in the bottles or
            Message 5 of 13 , Sep 3, 2001
              Hello,
              My suspicions are that the propane in the bottles is freezing up. You could try
              warming them with water to help keep the pressure up in the bottles or switch to
              larger tanks.
              I use two 100# bottles hooked up in parallel to a manifold opening both tanks
              at the same time when I plan a long burn. I also normally operated my burner at
              15 to 20 psi fuel pressure with the gage mounted at the burner. You may also
              have to change your jet size to a smaller one. A # 45 drill size will give you a
              rich mixture. I settled for a #54 drill size jet size for mine.

              Rupert

              zbadone@... wrote:
              >
              > I've been trying to tweek my furnace and would like to know a few things.
              >
              > I have a monster burner, 1-1/4" burner tube and have changed over to
              > the Tweco 1/4 welding tip idea. It's the one recommended
              > on rreil site. It measures 1-1/2" long and tapered. I brazed a 1/4 nut
              > onto my 1/8" T fitting and screwed in the tip.
              > It's working outside my furnace with a make-shift tapered flare. What
              > I'm trying to determine is how large a propane
              > tank everyone else is using with these types of large burners. After
              > 12 minutes or so my furnace starts to sputter, I am only running my
              > setup at 7-10 psi with a .045 (?) welding tip. I am trying to figure
              > out this sputtering effect.
              >
              > Recently I've built a manifold system with 2-20lb tanks. I thought
              > that I was not supplying enough propane over a period of time,
              > but with two tanks hooked up together, both open, I had the same
              > sputtering. I tried opening one tanks only then when the sputtering
              > started I opened
              > the second tanks, then closed the first. This stopped the sputtering
              > the only time I tried this.
              >
              > Could it be light wind effecting the operation of my burner? But why
              > would it do this everytime around the same time?
              > 10-12 minutes into a burn.
              >
              > Any ideas?
              >
              > Thanks.
              >
              > Please visit our sponsor: Budget Casting Supply
              > http://budgetcastingsupply.com/
              >
              > The Home Foundrymen's Association website may be found here: http://members.nbci.com/HWilkinson/
              > It includes member project pages & links
              >
              > To unsubscribe from this group, send an email to:
              > hobbicast-unsubscribe@egroups.com
              >
              >
              >
              > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

              --
              yvt

              Rupert Wenig
              RR.2, Box 1 Building an uniflow engine
              Camrose, Alberta, Canada Bore 1.25"
              T4V 2N1 Stroke 1.5"
              rwenig@... Flywheel dia. 5"
              http://www.cable-lynx.net/~rwenig/index.html
            • Joe and Betty Harralson
              Hi, One possibility is that the propane tanks are freezing up or the valves etc are freezing. You can often see ice or frost forming on the tank and lines. As
              Message 6 of 13 , Sep 4, 2001
                Hi,

                One possibility is that the propane tanks are freezing up or the valves etc
                are freezing. You can often see ice or frost forming on the tank and lines.
                As the propane is drawn out it cools the tank. (this is the basic way a
                refrigerator works!) I have had this problem in the winter when melting
                bronze. The burner didn't sputter but the fuel/air mix became too lean
                resulting in an oxidizing atmosphere that literally burned up the bronze.
                With two tanks when you switch to the second tank, it isn't cold yet since
                you haven't drawn out any propane, but it would probably take the same
                amount of time until the burner would again sputter.

                Joe Harralson

                ----- Original Message -----
                From: <zbadone@...>
                To: <hobbicast@yahoogroups.com>
                Sent: Friday, August 31, 2001 11:37 PM
                Subject: [hobbicast] 20lb Propane tank and pressure?


                > I've been trying to tweek my furnace and would like to know a few things.
                >
                > I have a monster burner, 1-1/4" burner tube and have changed over to
                > the Tweco 1/4 welding tip idea. It's the one recommended
                > on rreil site. It measures 1-1/2" long and tapered. I brazed a 1/4 nut
                > onto my 1/8" T fitting and screwed in the tip.
                > It's working outside my furnace with a make-shift tapered flare. What
                > I'm trying to determine is how large a propane
                > tank everyone else is using with these types of large burners. After
                > 12 minutes or so my furnace starts to sputter, I am only running my
                > setup at 7-10 psi with a .045 (?) welding tip. I am trying to figure
                > out this sputtering effect.
                >
                > Recently I've built a manifold system with 2-20lb tanks. I thought
                > that I was not supplying enough propane over a period of time,
                > but with two tanks hooked up together, both open, I had the same
                > sputtering. I tried opening one tanks only then when the sputtering
                > started I opened
                > the second tanks, then closed the first. This stopped the sputtering
                > the only time I tried this.
                >
                > Could it be light wind effecting the operation of my burner? But why
                > would it do this everytime around the same time?
                > 10-12 minutes into a burn.
                >
                > Any ideas?
                >
                > Thanks.
                >
                >
                >
                > Please visit our sponsor: Budget Casting Supply
                > http://budgetcastingsupply.com/
                >
                > The Home Foundrymen's Association website may be found here:
                http://members.nbci.com/HWilkinson/
                > It includes member project pages & links
                >
                > To unsubscribe from this group, send an email to:
                > hobbicast-unsubscribe@egroups.com
                >
                >
                >
                > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                >
                >
              • zbadone@bigfoot.com
                Hi, I don t really remember checking for visable frost on the tanks, but then again I live in sunny Florida and had melted aluminum mid afternoon, with the sun
                Message 7 of 13 , Sep 4, 2001
                  Hi,

                  I don't really remember checking for visable frost on the tanks, but
                  then again I live in sunny Florida
                  and had melted aluminum mid afternoon, with the sun beating down upon
                  my back. I think one of these day I will topple
                  over due to heat!
                  The next time I fire up the furnace I will monitor the tanks for
                  frost, PSI settings and the exact time frame that the sputtering occurs.

                  At first I thought that by using a 20lb tank that I wasn't suppling
                  enough propane to my burner, So the idea came about that by using
                  two tanks manifolded together that this would increase the surface
                  area for propane liquid to evaporate suppling my gas to my burner.
                  Well it did not seem to work as planned. So then I decided since I was
                  getting this 'Sputtering' around 12 minutes with 1 or 2 tanks,
                  that I would use 1 tank first, then around 10 minutes or so switch the
                  other tank on, then turn off the 1st tank, and repeat as long as
                  neccesary.
                  I was hoping to use this setup to melt other metals then aluminum.

                  The aluminum had already melted, just when the sputtering started. At
                  what temp? I don't know. Didn't have my thermocouple working yet.
                  >
                  > One possibility is that the propane tanks are freezing up or the
                  valves etc
                  > are freezing. You can often see ice or frost forming on the tank
                  and lines.
                  > As the propane is drawn out it cools the tank. (this is the basic way a
                  > refrigerator works!) I have had this problem in the winter when melting
                  > bronze. The burner didn't sputter but the fuel/air mix became too lean
                  > resulting in an oxidizing atmosphere that literally burned up the
                  bronze.
                  > With two tanks when you switch to the second tank, it isn't cold yet
                  since
                  > you haven't drawn out any propane, but it would probably take the same
                  > amount of time until the burner would again sputter.
                  >
                  > Joe Harralson
                  >
                  > ----- Original Message -----
                  > From: <zbadone@b...>
                  > To: <hobbicast@y...>
                  > Sent: Friday, August 31, 2001 11:37 PM
                  > Subject: [hobbicast] 20lb Propane tank and pressure?
                  >
                  >
                  > > I've been trying to tweek my furnace and would like to know a few
                  things.
                  > >
                  > > I have a monster burner, 1-1/4" burner tube and have changed over to
                  > > the Tweco 1/4 welding tip idea. It's the one recommended
                  > > on rreil site. It measures 1-1/2" long and tapered. I brazed a 1/4 nut
                  > > onto my 1/8" T fitting and screwed in the tip.
                  > > It's working outside my furnace with a make-shift tapered flare. What
                  > > I'm trying to determine is how large a propane
                  > > tank everyone else is using with these types of large burners. After
                  > > 12 minutes or so my furnace starts to sputter, I am only running my
                  > > setup at 7-10 psi with a .045 (?) welding tip. I am trying to figure
                  > > out this sputtering effect.
                  > >
                  > > Recently I've built a manifold system with 2-20lb tanks. I thought
                  > > that I was not supplying enough propane over a period of time,
                  > > but with two tanks hooked up together, both open, I had the same
                  > > sputtering. I tried opening one tanks only then when the sputtering
                  > > started I opened
                  > > the second tanks, then closed the first. This stopped the sputtering
                  > > the only time I tried this.
                  > >
                  > > Could it be light wind effecting the operation of my burner? But why
                  > > would it do this everytime around the same time?
                  > > 10-12 minutes into a burn.
                  > >
                  > > Any ideas?
                  > >
                  > > Thanks.
                • cmckeown@iprimus.com.au
                  Well I ve had exactly the same experience with my burner. Running at around 10PSI of back pressure and 10 min into the burn it would start to splutter. I ve
                  Message 8 of 13 , Sep 5, 2001
                    Well I've had exactly the same experience with my burner. Running at
                    around 10PSI of back pressure and 10 min into the burn it would start
                    to splutter. I've made a couple of changes and can now control the
                    splutter when it creeps in. I've got a theory which to some oricles
                    may not seem sound, but here goes.
                    I belive that the problem is not generated at the bottle end, but at
                    the other end of the show, the furnace. No matter what size bottles
                    I used 9kg, 45kg or both manifolded together the damm thing still
                    spluttered.
                    Normally asperated burners rely on the velocity of the gas through
                    the venturi to generate the air flow into the burner. The higher the
                    gas velocity the more air that can be drawn in and the greater the
                    mix pressure in the burner tube. When the mix reaches the flared end
                    the pressure is rapidly dropped and the combustion occurs. As the
                    furnace heats up there is also a slight pressure increase inside the
                    furnace. When this pressure change is great enough combustion does
                    start and stop inside the burner tube causing the spluttering. When
                    I increase the back pressure a couple of PSI thus increasing the gas,
                    air flow and burner tube pressure slightly the spluttering stops. I
                    adjust this back pressure slightly each time the spluttering occurs
                    up to around 15 psi. At this point the spluttering does not reoccur.
                    In my burner (see the files section for drawing) I have reduced the
                    gas orifice down to 0.035". This has allowed me to greatly increase
                    the gas velocity for the same volume used and control the spluttering.
                    As I increase the gas flow up to a back pressure of 15 psi there is
                    no chilling or frosting of the bottle, even in winter.
                    I've certainly never experienced this sluttering with my forced air
                    burner running at the same back pressures.
                    Now I'm sure there's a couple or readers who may differ on my
                    observations so it's over to you.

                    Cheers
                    Cameron

                    Victoria, Australia where it's spring and starting to feel a bit
                    warmer.



                    --- In hobbicast@y..., zbadone@b... wrote:
                    > I've been trying to tweek my furnace and would like to know a few
                    things.
                    >
                    > I have a monster burner, 1-1/4" burner tube and have changed over to
                    > the Tweco 1/4 welding tip idea. It's the one recommended
                    > on rreil site. It measures 1-1/2" long and tapered. I brazed a 1/4
                    nut
                    > onto my 1/8" T fitting and screwed in the tip.
                    > It's working outside my furnace with a make-shift tapered flare.
                    What
                    > I'm trying to determine is how large a propane
                    > tank everyone else is using with these types of large burners. After
                    > 12 minutes or so my furnace starts to sputter, I am only running my
                    > setup at 7-10 psi with a .045 (?) welding tip. I am trying to figure
                    > out this sputtering effect.
                    >
                    > Recently I've built a manifold system with 2-20lb tanks. I thought
                    > that I was not supplying enough propane over a period of time,
                    > but with two tanks hooked up together, both open, I had the same
                    > sputtering. I tried opening one tanks only then when the sputtering
                    > started I opened
                    > the second tanks, then closed the first. This stopped the sputtering
                    > the only time I tried this.
                    >
                    > Could it be light wind effecting the operation of my burner? But why
                    > would it do this everytime around the same time?
                    > 10-12 minutes into a burn.
                    >
                    > Any ideas?
                    >
                    > Thanks.
                  • Dale Smith
                    Allow me to add my absolute ignorance on the subject: Cameron, I think you are on target. I have only played with my NA burner out in the open but enough to
                    Message 9 of 13 , Sep 5, 2001
                      Allow me to add my absolute ignorance on the subject:

                      Cameron, I think you are on target. I have only played with my NA burner out
                      in the open but enough to find they are very touchy. On the other hand, I
                      have never had a problem with my forced air/ low pressure burner which
                      consists of a 1/8 inch pipe for a jet. BUT... I do have to start with low
                      airflow and low propane and increase gradually as the furnace warms up.

                      True, I am using whatever the standard pressure is from a propane regulator
                      but it is essentially unrestricted and delivering a BUNCH of propane from
                      the way it empties a 100 pound bottle. Frost, freezing, icing, etc. has
                      never entered my mind. In fact, sometimes I would welcom a frosty propane
                      bottle. I would hug it tightly on one of our 107 degree days.

                      I won't vote on the details... except to say that they make sense to me...
                      but I certainly believe your are looking in the right place.

                      Dale Smith

                      ----- Original Message -----
                      From: <cmckeown@...>
                      To: <hobbicast@yahoogroups.com>
                      Sent: Wednesday, September 05, 2001 9:43 PM
                      Subject: [hobbicast] Re: 20lb Propane tank and pressure?


                      > Well I've had exactly the same experience with my burner. Running at
                      > around 10PSI of back pressure and 10 min into the burn it would start
                      > to splutter. I've made a couple of changes and can now control the
                      > splutter when it creeps in. I've got a theory which to some oricles
                      > may not seem sound, but here goes.
                      > I belive that the problem is not generated at the bottle end, but at
                      > the other end of the show, the furnace. No matter what size bottles
                      > I used 9kg, 45kg or both manifolded together the damm thing still
                      > spluttered.
                      > Normally asperated burners rely on the velocity of the gas through
                      > the venturi to generate the air flow into the burner. The higher the
                      > gas velocity the more air that can be drawn in and the greater the
                      > mix pressure in the burner tube. When the mix reaches the flared end
                      > the pressure is rapidly dropped and the combustion occurs. As the
                      > furnace heats up there is also a slight pressure increase inside the
                      > furnace. When this pressure change is great enough combustion does
                      > start and stop inside the burner tube causing the spluttering. When
                      > I increase the back pressure a couple of PSI thus increasing the gas,
                      > air flow and burner tube pressure slightly the spluttering stops. I
                      > adjust this back pressure slightly each time the spluttering occurs
                      > up to around 15 psi. At this point the spluttering does not reoccur.
                      > In my burner (see the files section for drawing) I have reduced the
                      > gas orifice down to 0.035". This has allowed me to greatly increase
                      > the gas velocity for the same volume used and control the spluttering.
                      > As I increase the gas flow up to a back pressure of 15 psi there is
                      > no chilling or frosting of the bottle, even in winter.
                      > I've certainly never experienced this sluttering with my forced air
                      > burner running at the same back pressures.
                      > Now I'm sure there's a couple or readers who may differ on my
                      > observations so it's over to you.
                      >
                      > Cheers
                      > Cameron
                      >
                      > Victoria, Australia where it's spring and starting to feel a bit
                      > warmer.
                      >
                      >
                      >
                      > --- In hobbicast@y..., zbadone@b... wrote:
                      > > I've been trying to tweek my furnace and would like to know a few
                      > things.
                      > >
                      > > I have a monster burner, 1-1/4" burner tube and have changed over to
                      > > the Tweco 1/4 welding tip idea. It's the one recommended
                      > > on rreil site. It measures 1-1/2" long and tapered. I brazed a 1/4
                      > nut
                      > > onto my 1/8" T fitting and screwed in the tip.
                      > > It's working outside my furnace with a make-shift tapered flare.
                      > What
                      > > I'm trying to determine is how large a propane
                      > > tank everyone else is using with these types of large burners. After
                      > > 12 minutes or so my furnace starts to sputter, I am only running my
                      > > setup at 7-10 psi with a .045 (?) welding tip. I am trying to figure
                      > > out this sputtering effect.
                      > >
                      > > Recently I've built a manifold system with 2-20lb tanks. I thought
                      > > that I was not supplying enough propane over a period of time,
                      > > but with two tanks hooked up together, both open, I had the same
                      > > sputtering. I tried opening one tanks only then when the sputtering
                      > > started I opened
                      > > the second tanks, then closed the first. This stopped the sputtering
                      > > the only time I tried this.
                      > >
                      > > Could it be light wind effecting the operation of my burner? But why
                      > > would it do this everytime around the same time?
                      > > 10-12 minutes into a burn.
                      > >
                      > > Any ideas?
                      > >
                      > > Thanks.
                      >
                      >
                      > Please visit our sponsor: Budget Casting Supply
                      > http://budgetcastingsupply.com/
                      >
                      > The Home Foundrymen's Association website may be found here:
                      http://members.nbci.com/HWilkinson/
                      > It includes member project pages & links
                      >
                      > To unsubscribe from this group, send an email to:
                      > hobbicast-unsubscribe@egroups.com
                      >
                      >
                      >
                      > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
                      >
                      >
                    • zbadone@bigfoot.com
                      I am sort of glad to hear I am not the only one with this sputtering effect. I will change my Tweco tip to a smaller size then I am currently using and
                      Message 10 of 13 , Sep 6, 2001
                        I am sort of glad to hear I am not the only one with this sputtering
                        effect. I will
                        change my Tweco tip to a smaller size then I am currently using and
                        increase the gas pressure a bit
                        to see if I can surpress this sputtering effect.

                        Thanks for the info. I will post my results the next time I lite up
                        the furnace.


                        --- In hobbicast@y..., cmckeown@i... wrote:
                        > Well I've had exactly the same experience with my burner. Running at
                        > around 10PSI of back pressure and 10 min into the burn it would start
                        > to splutter. I've made a couple of changes and can now control the
                        > splutter when it creeps in. I've got a theory which to some oricles
                        > may not seem sound, but here goes.
                        > I belive that the problem is not generated at the bottle end, but at
                        > the other end of the show, the furnace. No matter what size bottles
                        > I used 9kg, 45kg or both manifolded together the damm thing still
                        > spluttered.
                        > Normally asperated burners rely on the velocity of the gas through
                        > the venturi to generate the air flow into the burner. The higher the
                        > gas velocity the more air that can be drawn in and the greater the
                        > mix pressure in the burner tube. When the mix reaches the flared end
                        > the pressure is rapidly dropped and the combustion occurs. As the
                        > furnace heats up there is also a slight pressure increase inside the
                        > furnace. When this pressure change is great enough combustion does
                        > start and stop inside the burner tube causing the spluttering. When
                        > I increase the back pressure a couple of PSI thus increasing the gas,
                        > air flow and burner tube pressure slightly the spluttering stops. I
                        > adjust this back pressure slightly each time the spluttering occurs
                        > up to around 15 psi. At this point the spluttering does not reoccur.
                        > In my burner (see the files section for drawing) I have reduced the
                        > gas orifice down to 0.035". This has allowed me to greatly increase
                        > the gas velocity for the same volume used and control the spluttering.
                        > As I increase the gas flow up to a back pressure of 15 psi there is
                        > no chilling or frosting of the bottle, even in winter.
                        > I've certainly never experienced this sluttering with my forced air
                        > burner running at the same back pressures.
                        > Now I'm sure there's a couple or readers who may differ on my
                        > observations so it's over to you.
                        >
                        > Cheers
                        > Cameron
                      • Joe and Betty Harralson
                        Cameron, Your theory makes sense to me, there are obviously a number of problems that could cause stuttering besides the freezing problem. Joe Harralson ...
                        Message 11 of 13 , Sep 6, 2001
                          Cameron,

                          Your theory makes sense to me, there are obviously a number of problems that
                          could cause stuttering besides the freezing problem.

                          Joe Harralson
                          ----- Original Message -----
                          From: <cmckeown@...>
                          To: <hobbicast@yahoogroups.com>
                          Sent: Wednesday, September 05, 2001 7:43 PM
                          Subject: [hobbicast] Re: 20lb Propane tank and pressure?


                          > Well I've had exactly the same experience with my burner. Running at
                          > around 10PSI of back pressure and 10 min into the burn it would start
                          > to splutter. I've made a couple of changes and can now control the
                          > splutter when it creeps in. I've got a theory which to some oricles
                          > may not seem sound, but here goes.
                          > I belive that the problem is not generated at the bottle end, but at
                          > the other end of the show, the furnace. No matter what size bottles
                          > I used 9kg, 45kg or both manifolded together the damm thing still
                          > spluttered.
                          > Normally asperated burners rely on the velocity of the gas through
                          > the venturi to generate the air flow into the burner. The higher the
                          > gas velocity the more air that can be drawn in and the greater the
                          > mix pressure in the burner tube. When the mix reaches the flared end
                          > the pressure is rapidly dropped and the combustion occurs. As the
                          > furnace heats up there is also a slight pressure increase inside the
                          > furnace. When this pressure change is great enough combustion does
                          > start and stop inside the burner tube causing the spluttering. When
                          > I increase the back pressure a couple of PSI thus increasing the gas,
                          > air flow and burner tube pressure slightly the spluttering stops. I
                          > adjust this back pressure slightly each time the spluttering occurs
                          > up to around 15 psi. At this point the spluttering does not reoccur.
                          > In my burner (see the files section for drawing) I have reduced the
                          > gas orifice down to 0.035". This has allowed me to greatly increase
                          > the gas velocity for the same volume used and control the spluttering.
                          > As I increase the gas flow up to a back pressure of 15 psi there is
                          > no chilling or frosting of the bottle, even in winter.
                          > I've certainly never experienced this sluttering with my forced air
                          > burner running at the same back pressures.
                          > Now I'm sure there's a couple or readers who may differ on my
                          > observations so it's over to you.
                          >
                          > Cheers
                          > Cameron
                          >
                          > Victoria, Australia where it's spring and starting to feel a bit
                          > warmer.
                          >
                          >
                          >
                          > --- In hobbicast@y..., zbadone@b... wrote:
                          > > I've been trying to tweek my furnace and would like to know a few
                          > things.
                          > >
                          > > I have a monster burner, 1-1/4" burner tube and have changed over to
                          > > the Tweco 1/4 welding tip idea. It's the one recommended
                          > > on rreil site. It measures 1-1/2" long and tapered. I brazed a 1/4
                          > nut
                          > > onto my 1/8" T fitting and screwed in the tip.
                          > > It's working outside my furnace with a make-shift tapered flare.
                          > What
                          > > I'm trying to determine is how large a propane
                          > > tank everyone else is using with these types of large burners. After
                          > > 12 minutes or so my furnace starts to sputter, I am only running my
                          > > setup at 7-10 psi with a .045 (?) welding tip. I am trying to figure
                          > > out this sputtering effect.
                          > >
                          > > Recently I've built a manifold system with 2-20lb tanks. I thought
                          > > that I was not supplying enough propane over a period of time,
                          > > but with two tanks hooked up together, both open, I had the same
                          > > sputtering. I tried opening one tanks only then when the sputtering
                          > > started I opened
                          > > the second tanks, then closed the first. This stopped the sputtering
                          > > the only time I tried this.
                          > >
                          > > Could it be light wind effecting the operation of my burner? But why
                          > > would it do this everytime around the same time?
                          > > 10-12 minutes into a burn.
                          > >
                          > > Any ideas?
                          > >
                          > > Thanks.
                          >
                          >
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