mr.cyclopede Posted August 10, 2019 Report Share Posted August 10, 2019 Hello everybody Bonjour from France, and from a froggy ! I'm a lucky buyer of a beautiful second hand Scandia IWG350 gas kiln I will pick up next month, and start to get any information, doc about it (user manual, plan,...). More especially I will have to proceed to a N-gas => LPG-gas conversion. On a Scandia catalogue I've seen that both versions exist, so I expect from rhe best to the worst that nothing to be modified or a complete change of the 4 burners. The more logical would be to get smaller diameter injectors. Before experimentating, it would be great to have the more informations I can get, maybe one of you is using this Rolls-Royce. ScandiaOvnen A/S is closed now for nearly a decade, A norvegian group Scan-form is theoretically insuring the maintenance of the old Scandia, but as they're now only manufacturing electric kilns, they kick into touch...French Scandia dealer is also closed. If anyone interested, I found in my research a GS300/600 operation manual (jet version of IWG) I would be happy to send. Thank you for your share and help Marc Link to comment Share on other sites More sharing options...
neilestrick Posted August 10, 2019 Report Share Posted August 10, 2019 The burner orifices will have to be changed in order to use different gas. LP orifices are smaller. Link to comment Share on other sites More sharing options...
mr.cyclopede Posted August 10, 2019 Author Report Share Posted August 10, 2019 Hi Neilestriek Thanks for your answer That's what I'm expecting, but as no spare sparts are more available and because these venturi burners were also directly manufactured by Scandia, I'm not sure that Ill be possible to find adequate injectors, and probably Will I have to make them machined on demand. what I'd like to know is the value for the new diameters,. I'll be able to dismantle a burner after summer holidays to mesure the present one, and I wonder if there is a conversion table of both values when you get the other nominals parameters (for the IWG350 4 burners, 80kW and 80-90mb pressure). Link to comment Share on other sites More sharing options...
Fred Sweet Posted August 10, 2019 Report Share Posted August 10, 2019 mr.cyclopede- You May want to do a little research on changing orifice sizes at Ward Burner Systems. Mark Ward has a copies of articles he has written on his website. Of particular interest to you might be the following: http://www.wardburner.com/orificesmessing.html He also has an orifice chart and replacement orifices available at: http://www.wardburner.com/otherproducts/orificechartsplugs.html If you would like to contact him directly to find out whether he can confirm the suitability for Scandinavia kilns, use the following: info@wardburner.com Hope this may be helpful to you. Regards, Fred Link to comment Share on other sites More sharing options...
Bill Kielb Posted August 10, 2019 Report Share Posted August 10, 2019 2 hours ago, mr.cyclopede said: Hi Neilestriek Thanks for your answer That's what I'm expecting, but as no spare sparts are more available and because these venturi burners were also directly manufactured by Scandia, I'm not sure that Ill be possible to find adequate injectors, and probably Will I have to make them machined on demand. what I'd like to know is the value for the new diameters,. I'll be able to dismantle a burner after summer holidays to mesure the present one, and I wonder if there is a conversion table of both values when you get the other nominals parameters (for the IWG350 4 burners, 80kW and 80-90mb pressure). There are conversion tables but the interesting aspect of this will be if the existing Venturi will function at lower velocity. This appears to be a medium pressure machine so I am going to suggest at least looking at the two venturis (Nat gas vs Propane) for an obvious size difference. If they are nearly identical in shape and size (exterior of burner) then I would go ahead and try the orifice change. There are many orifice tables on the Internet. My sense is you will need new burner venturis with new orifices. Link to comment Share on other sites More sharing options...
mr.cyclopede Posted August 10, 2019 Author Report Share Posted August 10, 2019 Hello Fred & Bill Will tomorrow mail to wardburner, I suppose might not be very usefull until I get a burner dismantled to give some dimensions. I read a bit of its website, so no way to call him unless I have a minimum of data concerning the kiln but also the pressure delivered by my gas provider (have a domestis but large 2t propane tank), from what I've I've seen with a plomber neighbourg, no problem of minimum pressure. Will also have to convert, we're talking MKSI language here !! Bill, my problem is that I do not have for instants any data or idea if there is a obvious size venturi difference beetween natural and LP versions. No information at all, I expect to have soon a comparison as I contacted the former Scandia dealer for France, who is now retired. He still own a spare burner he never sold, he expect to be a LPG version as a large majority of the kilns he sold were in this version. That way, changing both injectors and venturi might be more complex and expensive than changing here a full burner (transport fares, customs, american vs europeans dimensions,...). Moreover, from what I see on the picture below, Scandia burners bodies are in one piece (a bit like Guri venturi burners on Wardbeurner), no possibility to change only the venturi part... Link to comment Share on other sites More sharing options...
Bill Kielb Posted August 11, 2019 Report Share Posted August 11, 2019 On 8/10/2019 at 4:47 PM, mr.cyclopede said: Hello Fred & Bill Will tomorrow mail to wardburner, I suppose might not be very usefull until I get a burner dismantled to give some dimensions. I read a bit of its website, so no way to call him unless I have a minimum of data concerning the kiln but also the pressure delivered by my gas provider (have a domestis but large 2t propane tank), from what I've I've seen with a plomber neighbourg, no problem of minimum pressure. Will also have to convert, we're talking MKSI language here !! Bill, my problem is that I do not have for instants any data or idea if there is a obvious size venturi difference beetween natural and LP versions. No information at all, I expect to have soon a comparison as I contacted the former Scandia dealer for France, who is now retired. He still own a spare burner he never sold, he expect to be a LPG version as a large majority of the kilns he sold were in this version. This may help or maybe not and apologies in advance for the rough form but this is what comes to my mind. If I look at your burner, the orifice should be located as marked in the picture so likely replaceable. I only had an imperial orifice chart handy so I converted KW to BTU, divided it equally among the four burners, and looked up the size required for propane. Now the question I have is will this Venturi work with the new orifice all of which is dependent on velocity and the amount of air brought in which is a function of the contraction in the Venturi and velocity through it. The interesting thing is 80-90mb is about 1psi give or take. Is that the specification under natural gas? The number and range seems odd. As a matter of observation 270,000 btu seems a bit small for this kiln so I am now wondering if this is 80 kw total or for each burner. so in the end, I think I would suggest accurate data on all before calling Ward. I am not sure we have a real grasp on what this is rated. Once the real data is in though, pretty easy to resolve I think. Link to comment Share on other sites More sharing options...
mr.cyclopede Posted August 11, 2019 Author Report Share Posted August 11, 2019 I don't see any reason for apologies Bill, you're very helpfull. 80-90mb pressure should be for both version if I correctly read the Scandia catalogue sheet below (in danish, but easily tranlated by Chrome): http://www.scandiaovnen.dk/skema02a4/skema02a4.htm I have the same question than you concerning the 80kW, For each burner or as a total. Moreover 80kW is indicated on the identification plate on the kiln, and 60kW on the Scandia sheet... So you're right, getting accurate data is essential, that's my aim by searching any official doc or user feedback, waiting to have a burner in hand next month. Could'nt get any here in France or around, very strange as ScandiaOvnen has a very solid reputation and must have sold many of this model. Link to comment Share on other sites More sharing options...
Bill Kielb Posted August 11, 2019 Report Share Posted August 11, 2019 Impressive kiln, 12 cubic feet, brick and fiber offered at the same pressure for natural gas and propane which indicates to me you have a chance that only an orifice change is the likely possibility. Why design two different venturis for production and inventory. Looks well insulated , nice and extremely simple to work with . looks like a nice find Link to comment Share on other sites More sharing options...
mr.cyclopede Posted August 11, 2019 Author Report Share Posted August 11, 2019 Hope so much you're right Bill ! Link to comment Share on other sites More sharing options...
mr.cyclopede Posted December 9, 2019 Author Report Share Posted December 9, 2019 Some forehead news Expecting the kiln to be delivered for Chrismas. As none of you ever certainly had to deal with a french administration, hard to understand about the delay ! Despite this I could dismantle the burners and hood. Burners looks, have the same dimensions and perf than a GACO MR-750. Orifice plugs have a 1,6mm diameter (0,062"). This 1,6 is close to the value you calculated Bill, and the former Scandia engineer I contacted remind of 1,6 and 2,5mm for GPL and N-gas. That would mean this kiln sold as a N-gas, whas fitted by mistake with GPL orifice plugs (now nearly certain that venturis and orifice spuds are the same). To support this thesis, the contineous issues the previous owner get to reach full power and temp, wich they attribute to the pressure delivered by the city gas supplier. Just contacted Mark Ward to buy an orifice chart and ask for his advice to buy the correct orifice plugs. Link to comment Share on other sites More sharing options...
CactusPots Posted December 9, 2019 Report Share Posted December 9, 2019 You can buy the smallest orifice and size it up with a set of drill bits used for this purpose until you get the correct flame. I did this when I built my own propane kiln. In my opinion, (which is only valid if Mark Ward confirms), is that the burners are best fine tuned as I described. Link to comment Share on other sites More sharing options...
Bill Kielb Posted December 9, 2019 Report Share Posted December 9, 2019 8 hours ago, mr.cyclopede said: Some forehead news Expect the kiln to be delivered for Chrismas. As none of you ever certainly had to deal with a french administration, hard to understand about the delay ! Despite this I could dismantle the burners and hood. Burners looks, have the same dimensions and perf than a GACO MR-750. Orifice plugs have a 1,6mm diameter (0,062"). This 1,6 is close to the value you calculated Bill, and the former Scandia engineer I contacted remind of 1,6 and 2,5mm for GPL and N-gas. That would mean this kiln sold as a N-gas, whas fitted by mistake with GPL orifice plugs (now nearly certain that venturis and orifice spuds are the same). To support this thesis, the contineous issues the previous owner get to reach full power and temp, wich they attribute to the pressure delivered by the city gas supplier. Just contacted Mark Ward to buy an orifice chart and ask for his advice to buy the correct orifice plugs. Good find! Thinking about this I believe you have it right. Small orifice, less energy regardless of pressure under natural gas and probably bad mixture. Great find, I would agree your assessment is very likely correct. Nice find, nice kiln! PS if the engineers picked 1.6 mm I would definitely stick with their design unless after operation you can confirm they are too small. They are pressure dependent. Link to comment Share on other sites More sharing options...
mr.cyclopede Posted December 9, 2019 Author Report Share Posted December 9, 2019 Thank you Bill Should I add that watching at the MR750 in different shops, they are oftenly sold with drill size 50 plugs on propane configuration, but sometimes also with 38 ones, wich I don't understand why (Lower pressure use ?) https://www.aardvarkclay.com/products.php?cat=228 https://shop.clay-planet.com/mr-750-venturi-burner.aspx Dual values of 80-90mb as nominal pressure are written on the Scandia brochure which present the both N-gas and LPG versions. 80 is indicated on my ident plate, could 90 be for the GPL..? PS too: will first test the present config 1,6 config for sure. If both engineer are wrong or charts tell something else I will order plugs (wich should be smaller IMO. Greatest find was the burner model, in orfer to get its spare parts ! Link to comment Share on other sites More sharing options...
Bill Kielb Posted December 9, 2019 Report Share Posted December 9, 2019 On 12/9/2019 at 2:03 PM, mr.cyclopede said: Thank you Bill Should I add that watching at the MR750 in different shops, they are oftenly sold with drill size 50 plugs on propane configuration, but sometimes also with 38 ones, wich I don't understand why (Lower pressure use ?) https://www.aardvarkclay.com/products.php?cat=228 https://shop.clay-planet.com/mr-750-venturi-burner.aspx Dual values of 80-90mb as nominal pressure are written on the Scandia brochure which present the both N-gas and LPG versions. 80 is indicated on my ident plate, could 90 be for the GPL..? PS too: will first test the present config 1,6 config for sure. If both engineer are wrong or charts tell something else I will order plugs (wich should be smaller IMO. Greatest find was the burner model, in orfer to get its spare parts ! I looked at the links and so far I think everything is consistent. The #50 orifice at (80-90mb) is good for our educated guess of 20Kw per burner (~70K Btu) and I believe the # 28 yields about that amount under typical Natural gas pressures. Interesting to note that a #38 orifice using propane at 11" of W.C. is spot on as well. 69 mb of pressure is equal to 27.72" W.C. = 1 PSI. Pressure to energy relationship output is not linear. As the pressure goes up the energy (Kw or Btu) increases exponentially. That is to say if we increase pressure by 10%, the amount of energy we get is significantly more than 10%. Propane is provided in pressurized cylinders which generally are relatively high fill pressures to increase stored capacity, as opposed to networked natural gas which usually establishes lower pressures for safety, leakage et...….. The 80 - 90 Mb machine rating establishes the operational design pressures, you will likely operate your machine near these and the #50 orifice seems spot on (20 Kw per burner or 70K Btu) per burner. More interesting to note is that a #38 orifice (Propane) at 11'' of W.C. is about 20Kw or 70K Btu per burner. That pressure thing! In the States generally most low pressure machines are design limited to 11" W.C. working pressure, with an input limit of 14" W.C. (About 27~40 mb) So I have attached the chart below which shows (Approximate): @7" W.C. (17mb) Natural Gas and a #28 Orifice = 70K BTU (20Kw) per burner @11" W.C. (27mb) Propane and a #38 Orifice = 70K BTU (20Kw) per burner And from the prior chart above @ 1 PSI (27.7" W.C., (69mb))Propane and a # 50 Orifice = 70K BTU (20Kw) per burner I think with this info, your present kiln, and diligent research you will be spot on or be able to tune it as needed. Still a good find in my view! Not sure that helps and hope I got all the intended numbers correct but I hope this will clear up in your mind how to adjust your regulator(s) on your machine for output. Next time remind me to just work in metric! Best of Luck! Link to comment Share on other sites More sharing options...
Mark C. Posted December 10, 2019 Report Share Posted December 10, 2019 Your offices look like standard ones world wide-Just buy some blank not yet drilled ones and drill out to recomended letter drill size-You can go down one size and work uop tom this. You will need to take off spark plugs and unscrew the burner head to get to office. They just screw on easy.If Scandia is still in business just get the right oines from them if out of business get blanks and drill them as brass drills easy.I keep a bag of most size offices in studio.I fire natural gas.I also keep blank ones as they are cheap. Mark Link to comment Share on other sites More sharing options...
Bill Kielb Posted December 10, 2019 Report Share Posted December 10, 2019 On 12/9/2019 at 8:29 PM, Mark C. said: Your offices look like standard ones world wide-Just buy some blank not yet drilled ones and drill out to recomended letter drill size-You can go down one size and work uop tom this. You will need to take off spark plugs and unscrew the burner head to get to office. They just screw on easy.If Scandia is still in business just get the right oines from them if out of business get blanks and drill them as brass drills easy.I keep a bag of most size offices in studio.I fire natural gas.I also keep blank ones as they are cheap. Mark Just a comment to add, if and when orifices are drilled it’s best to drill them from the backside to front. Most of the tables assume a uniform sharp edge orifice for entrance losses and any significant roughness or irregularity will affect the pressure drop across the orifice often significantly. An easy way to avoid these issues are to drill in the direction of flow as opposed to against it, Link to comment Share on other sites More sharing options...
Mark C. Posted December 10, 2019 Report Share Posted December 10, 2019 Yes as Bill says drill from the rear. Most offices have a cone shape in rear already and its easy to center drill in that cone.Its a point I overlooked but is important Link to comment Share on other sites More sharing options...
mr.cyclopede Posted December 10, 2019 Author Report Share Posted December 10, 2019 Bad news from Mark Ward this morning, saying that the GACO spuds and plugs are differents with buy burner... Thrue that connections diameters are different (1/4 iso 1/2"), but I have difficulties to imagine that with identical venturis , identical domain of use (BTU, pressure) the inner dimensions of the spuds are really different, and also why Scandia designers would completely change or recreate something that works well (GACO burners are certainly older and widespread). Such a likeness on the venturi is not a chance IMO, but whether a copy or a license deal beetween manufacturers. So I asked Mark to have the superior dimensions of the GACO spud in order to see if I could adapt my venturi, wich would allow me to keep the safety and lightning system present on it. Do you think I'm right ? Waiting now for the chart and 4 undrilled plugs for blind testing, in parallel with the essential test with present 1,6 plugs. Thank you Bill for the back to front drilling advice. Mark, unfortunately Scandia is closed for ten years, just a former technician I'm in contact with but no docs or parts catalogue... Link to comment Share on other sites More sharing options...
Bill Kielb Posted December 10, 2019 Report Share Posted December 10, 2019 31 minutes ago, mr.cyclopede said: Bad news from Mark Ward this morning, saying that the GACO spuds and plugs are differents with buy burner... Thrue that connections diameters are different (1/4 iso 1/2"), but I have difficulties to imagine that with identical venturis , identical domain of use (BTU, pressure) the inner dimensions of the spuds are really different, and also why Scandia designers would completely change or recreate something that works well (GACO burners are certainly older and widespread). Such a likeness on the venturi is not a chance IMO, but whether a copy or a license deal beetween manufacturers. So I asked Mark to have the superior dimensions of the GACO spud in order to see if I could adapt my venturi, wich would allow me to keep the safety and lightning system present on it. Do you think I'm right ? Waiting now for the chart and 4 undrilled plugs for blind testing, in parallel with the essential test with present 1,6 plugs. Thank you Bill for the back to front drilling advice. Mark, unfortunately Scandia is closed for ten years, just a former technician I'm in contact with but no docs or parts catalogue... I am thinking it is mute at this point. You have #50 (small) and when you get it all installed if your regulated pressure is more like 11” then you will drill these out to #38. You can enlarge them slowly if concerned and test in between. 11” will give you more likely useable propane tank life anyway. 1psi is more like Raku type designs. Now that you understand the machine, the #50 orifice likely gives you the best opportunity to make this match just reusing your existing. Just to add, even converting this to natural gas at this point is doable with drilling the orifices to #28. You would need to ensure that the piping to it would supply 80 kw at at least 7” of pressure. This is fairly small though and should be relatively easy to accomplish. Not sure if I am missing something here. Link to comment Share on other sites More sharing options...
mr.cyclopede Posted December 10, 2019 Author Report Share Posted December 10, 2019 For Mark Ward, the MR750 doesn't work well between 1 and 2 PSI, whatever the plug #... Meaning that I was wrong, venturis might be the same for different burners, as mine is coupled to a spud/plug made to work on an industrial assembly at this pressure. By the way, he has no more charts available to sell, would there anyone who have it and would be ok to scan and pm it to me ? Link to comment Share on other sites More sharing options...
Bill Kielb Posted December 10, 2019 Report Share Posted December 10, 2019 2 hours ago, mr.cyclopede said: For Mark Ward, the MR750 doesn't work well between 1 and 2 PSI, whatever the plug #... Meaning that I was wrong, venturis might be the same for different burners, as mine is coupled to a spud/plug made to work on an industrial assembly at this pressure. By the way, he has no more charts available to sell, would there anyone who have it and would be ok to scan and pm it to me ? I like Mark a bunch so there must be something I don’t understand. So first what will we be running the kiln on, natural gas or propane? Worst case regardless, you can buy four complete burners from the supplier you posted, definitely good for 14” Propane or 7” natural gas. My issue is whether (for propane) 14” or 1 psi they still are designed to pass the exact cubic feet of propane. Propane is about 2000 btu per cubic foot so whether at 1psi or 14”, the same amount of fuel will go through that Venturi. The 1psi model will have a greater pressure drop across the orifice. medium pressure machines (1psi) are often provided to industry so smaller diameter service pipe can be run to them reducing the requirement for expensive large diameter service piping. In the end if I can embed a #38 orifice the same depth within the existing Venturi that you have (I don't know why it would be different since the exact same amount of gas has to go through it) and it is an identical profile to the 750 burner I should be able to run this machine on propane and only be concerned with the delivered pressure to each orifice and proper orifice size for the given pressure. I think I am still missing something here. Maybe the embed depth and thread of the 1psi Venturi? Lots of charts for free on the internet, mostly imperial though Link to comment Share on other sites More sharing options...
mr.cyclopede Posted December 11, 2019 Author Report Share Posted December 11, 2019 As far as I can, i'd like to keep running the kiln at the pressure it was concepted, so around the 1PSI. service pipe after pressure regulator are not that small (see picture), 18mm inside diameter. Here again don't know if it depends on kiln gas configuration, but as nominal pressure beeing nearly the same, I tend to believe they're not. what's the interest running at 14" Bill ? You were talking about a more useable tank life, do you mean a lower gas consumption ? My tank is a burried 2 tons one, so no problem like 38kg bottles. I'll certainly order soon a Spud, 4 #50 and 4 undrilled plugs here: https://www.aardvarkclay.com/products.php?cat=228 No other way than a blind test before buying 4 burners in the worst situation. Link to comment Share on other sites More sharing options...
Bill Kielb Posted December 11, 2019 Report Share Posted December 11, 2019 Lower pressure is safer (leakage) and your system pressure can drop to a lower amount and still service loads. The amount of gas withdrawn will still be the same but your tank pressure will be operable down to a lower pressure which often allows folks to be capable to withdraw more gas. With a buried tank, this may not really matter as the tank will draw available heat from the ground and temperature will remain fairly constant. The service piping to the machine in general would need to be larger in diameter to support the load though. (See below) I seem to have lost track here, if you can operate at approximately at 1psi (69mb) and you have #50 orifices then you are good to go. If you have # 38 orifices, then add a regulator just upstream of the kiln and operate at 11” which is the best of both worlds actually. The question I am no longer clear about is what size orifices are in it now? As I said Those two venturis (#50 @ 69mb and #38@ 11”) should be Identical since regardless of the pressure they will flow the exact same cubic feet (cubic meters) of gas. So to clarify for me do you have # 28 orifices on the machine now ? Link to comment Share on other sites More sharing options...
mr.cyclopede Posted December 11, 2019 Author Report Share Posted December 11, 2019 Sorry I' certainly a bit confusing presently, orifices are 1,6mm = 0,062 in, so #50. Link to comment Share on other sites More sharing options...
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