Justin Poe Posted January 29, 2018 Share Posted January 29, 2018 So I do realize it is not constructed per reil design. I did this using another concept and before I even knew of reil. My bad on that. That being said, to "frozen forge" I thought as you suggested but the condition occurs even when I am holding it in my hand. Horizontal good, vertical bad. I guess it could still be picking up spent air but it happens instantly when I turn it upright. May have to rebuild as Mikey suggested but i would like to figure this out just to better my knowledge. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 29, 2018 Author Share Posted January 29, 2018 Any naturally aspirated burner will stall out if run in the vertical down position in your hand. How sharp an angle it can stand depends on how long the mixing tube is. At some point spent gasses from the flame will be driven by buoyancy into the burner entrance, replacing needed oxygenated air. This process can also happen to burners in forges if you don't prevent it, as has been suggested. There is no mystery here. Quote Link to comment Share on other sites More sharing options...
Justin Poe Posted January 29, 2018 Share Posted January 29, 2018 Ok, I am going to work on a shield for the intake and see if that helps. I may also extend the mixing tubes several inches. Thanks for the suggestions, I'll let you know how it goes. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 29, 2018 Author Share Posted January 29, 2018 The burner flame will create enough light to throw a shadow play on a smooth surface like cardboard, which is held a foot or so away; this will show the spent gasses as wavy lines on its surface. You can then move the burner's position until the clear but heated gas enters the burner; thus satisfying your self of exactly what is going on. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted January 29, 2018 Share Posted January 29, 2018 14 hours ago, Justin Poe said: Ok, I'm new to this site Welcome to IFI... Quote Link to comment Share on other sites More sharing options...
Justin Poe Posted January 30, 2018 Share Posted January 30, 2018 Good advice on the deflector. That solved my sputtering flame issue. However I also have the dragons breath issue as well as a few other things to fine tune. I'm going to search some other threads first as I am pretty sure those things have been discussed. Thanks for the help. Quote Link to comment Share on other sites More sharing options...
DavidF Posted January 30, 2018 Share Posted January 30, 2018 At a quick glance of the pic, it appears there may be some space where the burners enter the forge. If you have some insulation blanket, you can fill that void and be sure to rigidize the fiber blanket. That would also help when using the burner in the forge environment. I am not sure if that is an issue, but looking at the picture, I wanted to point out a possible airflow issue in the forge environment. If that does make a difference, I would use some refractory cement to further improve that potential air flow issue. Thee would be a trade off with being able to adjust the burners based on the design, but with my vertical burners, I saw a huge difference when I set the refractory cement with the burners and did not yet have the burner ports insulated versus when I had them insulated and used the forge for actual metal heating. Once I plugged up the ports as I described, the environment worked much bett with airflow going down the burners and out the doors as it should. It is also an easy test if you have scraps of fiber blanket you can put in there. Hope that makes a difference. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 30, 2018 Author Share Posted January 30, 2018 Fiber blanket is the quick and easy fix for too much secondary air being induced by burner flames, BUT, washers on the mixing tubes can be moved toward and away from the forge top, allowing some secondary air, which is needed for all but the best burner designs, in order to completely combust fuel gas within the forge. Variable is always the best measure on both burners and the forges they heat. 13 hours ago, Justin Poe said: Good advice on the deflector. That solved my sputtering flame issue. However I also have the dragons breath issue as well as a few other things to fine tune. One of the reasons that threaded pipe parts are still so popular with many burner builders is that a mistake can so easily be changed out; they also allow people to see flame improvement one step at a time. Seeing is believing. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 30, 2018 Author Share Posted January 30, 2018 there are two ways to end up with a good burner: follow the instructions of a well known successful design EXACTLY; Or design your own burner according to well-established design principles, after finding out what they are. Mix-and-match burners end up with the builder stuck between the dock and the boat; into the drink, you'll go. For instance, flame nozzles made from cast pipe reducers seldom work out well; this is because they can never be made to the best diameter for the mixing tube, and have no ability to be pushed forward or back, thus changing their width to length ratio, in order to be tuned to best match up with incoming gas and air flow. Nevertheless, I have seen perfect flames coming out of burners with pipe reducers used for flame nozzles; I've seen it twice in the last eighteen years--pretty poor odds. Quote Link to comment Share on other sites More sharing options...
NormanP Posted January 30, 2018 Share Posted January 30, 2018 Hi all - sorry to say I'm another newbie looking for some constructive criticism on a home made burner I've read as much as I can find (including Mikey's great book cover to cover several times) and put together an 1 1/4 burner that my son and I would like to use in a foundry. Most of the bits I could not get hold of - so I've matched up with what I could get locally or I could make on a small desktop hobby lathe. The mechanical bits I can work my way through but the bit I'm struggling with is looking at the flame coming out of the end and determining if it's good enough to melt metal. And if it is... then could it just be aluminium, or might it melt brass or even iron? Attached are 2 pictures of the flame I'm getting at ~27psi propane, (there was some cross wind when taking these so the first picture from above shows the drift). I'll try to pre-empt the dimension questions below: Burner tube ID is 35mm (38mm OD) and burner tube length (excluding air slots) is ~306mm (just short of the 9x guidance - but that's all I could fit in the lathe) Choke is sliding type, running forward towards the nozzle and opening the air intakes from the rear of the burner. Air intakes are squared off slots (thanks Mikey!) Propane jet is home made in brass - 40mm total length with 20mm of that an internal 14 degree taper cone starting at ~6.5mm running down to 1.7mm, (I read somewhere that 13 degrees is a good taper for gas but the closest cone tool I could get was 14 degrees). The 1.7mm then runs parallel for the remaining 20mm of the jet. Outside of the jet is tapered for the full length from 10mm down to ~3.5mm at the tip. This is screwed into a 10mm OD, ~7mm ID steel tube that exits the rear of the burner to the 8mm ID gas hose. Tip sits ~18mm back from the start of the burner tube. Stepped nozzle is ID 54mm and has a 55mm overhang from the end of the burner tube. Unfortunately it's not a 304 or 316 stainless nozzle and is already beginning to "peel". I'm thinking/hoping that's the cause of some of the orange streaks in the pictures. (Stainless tube is on order). When warmed up, the burner stays lit from about 2psi up to the full pressure from the 4 bar regulator - but I realise staying lit doesn't mean I'm getting the most heat we can get from the burner. The goal is to melt iron to cast into parts for a model engineering club my son goes to - the guys there have started making patterns for what they want already so no pressure on us to deliver then!! Thanks in advance for all advice offered. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 31, 2018 Author Share Posted January 31, 2018 The red streaks are probably from the nozzle material being oxidized away. The flame in the first photo is totally excellent. The flame in the second photo is typical of a burner that isn't properly tuned; even this flame would melt brass. The first flame in this large a burner will melt iron easily. If you take the time to properly bevel the forward and aft sides of the rectangular air openings, it will improve the burner still more. But congratulations on how well you've done already. Quote Link to comment Share on other sites More sharing options...
Justin Poe Posted January 31, 2018 Share Posted January 31, 2018 Mickey...on the washer comment. Are you saying to use actual washers like I'd buy at a hardware store around the carriage bolts to fit around the 3/4" mixing tubes or is there some other washers specific to burners? And by doing washers instead of completely filling in around the burners your saying it will help my forge efficiency. So don't do fire blanket and do do washers? Quote Link to comment Share on other sites More sharing options...
NormanP Posted January 31, 2018 Share Posted January 31, 2018 Thanks for the feedback Mike - I'll print the first photo out and keep it in my wallet I think I got the flame in the first photo more by good luck than by good judgement. I find it a lot easier to get a flame like the second photo - so I think I'll still be looking for hints on how to get the flame back to looking like photo 1. I'll certainly bevel the air openings and post another picture. I've added a sketch of the home made gas jet that screws into the end of a 10mm OD, (~7mm ID) gas accelerator tube - do you think 20mm of parallel 1.7mm bore is too long/too short? 20mm of ~14 degree entrance cone and then 20mm of parallel bore suited the length of the cone burr tool and the 1.7mm drill I had - so that's what decided these dimensions, (I struggled to find any detailed information on gas jet design and I didn't want to try and drill 40mm of brass at 1.7mm to match a mig tip). Again, thanks in advance for any and all advice. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 31, 2018 Author Share Posted January 31, 2018 Justin, It would probably be easier to use a hole saw to make your own washer, although there are specialty washers that would do; the problem is time lost in trying to search them out. Once you have washers you need to keep them in place at the optimal height above the forge top, which can be done with spacers, or the washers can be held in place with a brazed nut and screw. Or you can leave the burners against the forge top, and add holes until just enough secondary air is allowed into the forge to completely combust the flame. Ceramic fiber should only be considered for testing, because it provides a source of toxic dust you don't want, and has to be handled every time you work on a burner. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted January 31, 2018 Author Share Posted January 31, 2018 1 hour ago, NormanP said: 20mm of ~14 degree entrance cone and then 20mm of parallel bore suited the length of the cone burr tool and the 1.7mm drill I had - so that's what decided these dimensions, (I struggled to find any detailed information on gas jet design and I didn't want to try and drill 40mm of brass at 1.7mm to match a mig tip). I looked at your drawing of a proposed gas jet, and it looks quite good to me; how it actually turns out is up to experiment. Larry Zoeller first changed out my original schedule #40 1/8" gas pipe for a schedule #80 pipe. It worked so much better that he no longer needed 1-1/2" bores from long MIG tips. For the first time short MIG tips worked fine; the difference was in the heavier pipe's smaller inside diameter, which provided a much smoother gas flow at the transition from gas pipe to gas jet. So, I feel confident that you are on the right track. As to tuning your burner's flame, you need to pay attention to how much overhang you allow between the end of the mixing tube and the end of the flame nozzle. The longer the distance the softer the flame. The shorter the distance the harder the flame. Photo one is a hard flame. You only need to shorten the overhang until the flames becomes unstable, and then add a little distance to come up with a stable hard flame Quote Link to comment Share on other sites More sharing options...
NormanP Posted February 1, 2018 Share Posted February 1, 2018 Hi all, I've beveled the lead and trail edges of the air intakes. I squared them off a little more too. I've reworked the nozzle fitting so it can be adjusted (first version was completely fixed). Thanks for the tuning advice Mike, it's amazing how much difference moving the nozzle only a few millimeters can make to the flame stability! I found I could shorten the nozzle by about 5mm compared to the original length and keep the stability. The new stainless nozzle tubing has not arrived yet, so I tested with the original, already oxidising, nozzle (the short extension piece you can see was fitted to account for the space taken by the adjusting ring). Photos are below, the second one is suffering from some side wind but to my untrained eyes, the first 2 look similar to the first photo in my earlier post: Hopefully the stainless nozzle tube will arrive tomorrow and I'll get it fitted before Saturday - if the weather holds, we're going to try casting aluminium. I'm wondering how much re-tuning will be needed when the nozzle is surrounded by refractory? Is it back to the beginning due to back pressure etc?? All advice welcome. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 1, 2018 Author Share Posted February 1, 2018 Okay, the first two photos show that you have learned to build and tune the burner. All that happens when this kind of hard flame is contained in a forge or furnace is that the flame becomes more refined. Once the equipment heats up to incandescent temperatures the flame will appear much lighter; this is due to the background light from the equipment interior's surfaces. If you were to take the burner out into the open its flame would appear just the same tint of blue as before the forge heated up. What is going on in the third photo is softening of the flame; I assume from a little de-tuning? Pushed the nozzle forward too much perhaps? Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 3, 2018 Author Share Posted February 3, 2018 Another way to come up with .028" jet holes for more perfect 1/2" burners Annealed copper refrigeration tube is designed to easily bend without collapsing; it comes in several sizes; a few standard examples are: 0.071" outside diameter, with 0.028" inside diameter refrigeration tube will fit within a 1/8” tube (with a little drilling), which will then fit within a 3/16” tube (for 1/2” burners). A number #49drill bit leaves a .073” hole that is perfect for silver soldering a short length of the tubing into. A number #50 drill bit leaves a .070” hole that only needs one-thousandth of an inch sanded away to make a perfect interference fit into a MIG contact tip, etc. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 4, 2018 Author Share Posted February 4, 2018 Introduction to Vortex Burners To begin with, let’s clarify just what is meant by the term vortex burner; technically it’s any burner that swirls the fuel/air mixture at some point; so technically, nearly every stable fuel/air burner would qualify—even some Bunsen burners. Often, the term vortex burner is granted to those that swirl the flames they make. But, causing a flame to swirl happens way too late in the mixing process to provide more than minimal benefits; applied this way the title is complete hype. Forcing an air stream directly at the funnel wall of a linear burner will create a weak vortical flow, but at the cost of also increasing the air/gas mixture pressure through the passage. The special fans on “”V” burners, are used to power up an otherwise passive vortex by creating lateral spin—not forward push—at the funnel entrance; thus, all the energy is spent strengthening vortical flow down the funnel transit, which then increases incoming air flow, while dropping incoming air pressure, by speeding up the gas/air mixture’s forward velocity and spin rate, all the way through the burner to the flame nozzle, where pressure behind the flame is reduced still further. Positive pressure in the burner’s gas/air mixture severely limits how much a flame can be strengthened. So powering up vortical flow, instead of pushing the air, results in much larger and faster flames than are attainable with a standard forced air burner. Every part of a Vortex burner is designed either to enhance, or benefit from, the principles of vortical flow; so the name is actually relevant—not just something that sounds impressive. Once you construct an air/fuel burner that can produce a neutral compact flame (near to total combustion in the primary wave front) from LPG fuels, it would seem that it’s the most you're ever going to achieve. So, if the safety cautions to follow make you nervous, why would you go on to build this kind of burner? The truth is that performance involves more than complete and compact combustion. Further improvements can still be made, like: Much greater flame variance (turn-down range); more powerful flames from smaller burners; and the ability to simply change out flame nozzle diameters on a single burner, rather than switching between two or three separate burner sizes; all of these advantages are very much missing in all other fuel/air burners, including high performance jet-ejector tube types (mine). Vortex burners are quieter than other turbulent flame burners for the same reason that their flames are incredibly stable; because of more thorough air/fuel mixing. I believe they come as close to the silence of linear flames as turbulent flames can; these burners provide the same stable performance on the smallest burner you can construct. This enables miniature burner sizes (1/4” and under) with turn-down ranges, from a perfect flame, to be increased by an order of magnitude! When it comes to jumbo size burners (1-1/2” and larger) that extra flame stability happens to be very comforting; if you’ve ever run one of those monsters, than you know just how desirable a smoother flame is. Note: flame noise is generated by flame variance from millisecond to millisecond during combustion; such variance is mainly the product of imperfect fuel/air mixing; improved mixing results in increased flame stability, and therefore a reduction in flame noise. It should be noted that, since this is the first text on Vortex burners, it can’t possibly be “the last word” on this subject; that will take several years and thousands of burner builds to establish. For instance, I’ve concluded that a 3:1 impeller blade to mixing tube diameter is the highest ratio that can be safely employed, but what is the best ratio; or, the best ratio for each burner size and fan power? What are the absolute best proportions on a cone shape? What motor and control refinements are optimums for each funnel size and shape? Such particulars can only be established with feedback from many people over several years. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 4, 2018 Author Share Posted February 4, 2018 Safety Any powered burner design can suffer a back-fire through the fan, if you block its flame path at the source (ex. allowing the burner to fall over on its flame nozzle during operation); these burners will do so; instantly and every last time! Secure the burner in position before running it. Place your burner opening sufficiently high above a casting furnace’s floor to keep it clear of any spilled metal in case of crucible failure. Place burner openings out of the direct path of heating materials in forges. It is necessary to initiate fuel gas flow first, and then ignite the fuel/air mixture from the burner’s forward end (in front of the flame nozzle), BEFORE STARTING THE FAN MOTOR on Vortex burners; these are a combination of natural induction and fan powered burner. Initiating the flame nozzle dynamics first will strengthen the establishment of mixture flow direction; greatly reducing the chance of reversing fuel gas flow from backpressure at the funnel/fan interface, after the fan is turned on. Fans installed on this burner series generate increased back pressure at the funnel opening, because they are designed to create swirl, rather than to create forward thrust. If the normal direction of mixture flow isn’t already established, some fuel gas can accumulate at the fan to funnel joint, instead of all the gas being pushed into the mixing tube. Note: Fuel ignition follows starting the fan on standard forced-air burner designs, because fuel in such systems can collect in the combustion area of heating equipment, leading to minor explosions, when it’s ignited; so the fan is started first with those burners, to reduce this possibility. But, on Vortex burners, the fuel air mixture has no chance to collect in the combustion chamber with the burner lit, nor will starting a weak impeller fan blow out the burner’s flame. Close the gas feed, but keep the fan running, during Vortex burner shutdown; then it is best to remove the burner from your forge or furnace, if it is positioned facing downward. Furthermore, the burners fan should be left running, until your burner is completely cooled down and ready to be stored, even if it is removed from the heating equipment. Note: If you don’t already know it, “chimney effect” is caused by a reverse air flow in some heating equipment, once its burner is shut down. What happens is that, when a burner port is placed near the top of a horizontal gas forge, super-heated gases travel up and out of the burner port after shut down because of buoyancy, while cooler air enters into the forge or casting furnace through the exhaust opening to replace them; thus overheating any burner that can’t be completely sealed. Even if the burner could be sealed, delicate fan parts would get too hot to survive. Caution: The larger the burner the greater the danger from backpressure against the fan, because of the increased air pressure needed to power the vortex. Therefore, blade to mixing tube diameters, funnel shapes, and fan strengths that are safe enough on small burners are not necessarily acceptable on larger burners. You need to keep this in mind when tempted to depart from construction recommendations, or in substituting parts. Running a larger fan than recommended for a given mixing tube diameter (greater than a three to one ratio) increases back pressure beyond acceptable levels, thus escalating the danger from ignoring the safety procedures given above. The smaller the burner the less sensitive it will be to funnel shape in creating back pressure through the fan. Therefore, the larger the burner the longer its funnel should be. Caution: Even when back pressure is kept to a safe minimum, some of the fuel/air mixture can escape at the funnel to fan interface if sealant, such as thread locker, isn’t provided at this joint. It then will be drawn into the fan, to create a flashback hazard. Any burner can be snuffed out if it is placed in a vertical-down position, facing at a steep enough angle; what causes this is spent exhaust gases (which rise through buoyancy/displacement), and enter the burner’s air intake. To most safely install Vortex burners in horizontal tube forges, they should be aimed with the flame nozzle angling somewhat upward. If installed facing down, a Vortex burner’s plastic fan can easily be overheated by the chimney effect, when the burner isn’t running. Vortex burners used in any position other than the horizontal need ball-bearing axial fans. Motors with sleeve bearings are only meant to run in a horizontally placed burner, so that their bearings are positioned vertically; otherwise their lubricating oil will seep out, letting the bearings run dry and seize up. It isn’t legal anywhere in the U.S. to leave combustion equipment running unattended unless it is fully fitted out with an automatic fuel shut off system, which has first been inspected and approved by your local fire department. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 4, 2018 Author Share Posted February 4, 2018 3/4” Vortex burner with SST for 2” sausage covers Four years ago, when I started building vortex burners, the very large stainless steel sausage stuffing tube this burner uses was not available, and so I used a Metrokane thick wall wine funnel; it will still make the best burner (less back pressure at the funnel/fan interface), but is considerably more work than this one. If you choose to build your 3/4” burner with this part(recommended), then buy it now, so that you can closely measure its dimensions before purchasing any of the tubing parts, or the fan: Quote Link to comment Share on other sites More sharing options...
John in Oly, WA Posted February 5, 2018 Share Posted February 5, 2018 Hi Mikey - how would you make the transition from this sausage stuffer tube with a 2" exit diameter to the 3/4" mixing tube diameter? But that's coming from a position of knowing nothing about vortex burner, or any other burner, design. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 5, 2018 Author Share Posted February 5, 2018 John, I am planning to use an aluminum spacer tube. However, the SST you've choosen is very similar to the LEM Product SST I originally planned to use, and in accordance with our discussion during the casting group's meeting. I just ordered one of the SST you prefer, so that what I suggest will match up with your parts, so order yours now too. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted February 5, 2018 Author Share Posted February 5, 2018 The sausage stuffing tube you chose is nearly identical to one of the LEM Product's SST, I was referring to during our casting group discussion. Since they may not be completely identical, I just ordered the SST you prefer, and we will be able to continue when both of us have our tubes. In the meantime, I am typing up instructions based on one of them and will be able to post them as soon as the SST arrives, can be accurately measured, and any needed changes in the instructions can be made. Quote Link to comment Share on other sites More sharing options...
John in Oly, WA Posted February 5, 2018 Share Posted February 5, 2018 3/4" sausage stuffer tube ordered. Looking forward to this build. A rough sketch of what I imagine the burner will look like: Quote Link to comment Share on other sites More sharing options...
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