Another picture of flame, this is with a different fuel setting but you can not usually tell what the fuel setting is from the size of the flame, the entire surface of the bowl (clean bowl) has flame at even the smallest fuel flow, I suspect this is caused by the entire bowl surface staying hot enough to vaporize all the fuel no matter the amount ?
flame_2.JPG (6 Kb, 364 downloads)
The Sanders article states that the center-supplied combustion air blows a lot of the ash out of the burner into the bottom of the burner tank, I find this to be correct. I have been burning this heater 24/7 now for a few weeks and there is maybe a half inch of ash in the bottom of the tank.
I have recently been monitering the outside surface temperature of the burner tank. the thermometer is located at the top of the tank, next to the flue outlet, and the small stem of the thermometer is being held in contact with the tank surface by a small magnet. There is a 10 inch summertime tabletop type fan setting on top of a refrigerator about 6 ft from this heater, it is set on the lowest setting and is blowing air continuously across the upper section of the burner tank and the flue pipe.
With a fuel setting of .16 G/H the tank stays about 175-180 deg f, with a setting of about .20 G/H the tank stays about 200-210 degrees f, with a setting of .22 G/H the tank stays around 240-250 deg f. I am using a feed pump made from a suntec fuel oil fired furnace burner fuel pump, this pump is being turned very slowly by a GM automotive 12 volt DC windshield wiper motor (.16 G/H takes about 4 seconds for each revolution of the pump), by adjusting the voltage to this motor the fuel feed amount can be controled to a very fine level. The differance between .16 G/H and .25 G/H is only about 3 volts, haven't measured the actual voltage yet but have a log of my voltage control knob numbers so can figure this out eventually. I can hold the house at about any temp I want during any outside temps from a few degrees below zero or up to the mid 30's f using a fuel feed someplace between the .15 to .25 G/h, this tells me that I can eventually build an electronic temp control that will automatically adjust the fuel feed to hold the room temp at any preset temp just like a normal furnace wall thermostat unit. there can also be several safty devices built in to this unit.
I have been burning this heater 24/7 now for several weeks, it is left unatended for at least half the time, and I am sleeping most of the rest of the time. I have had it go out a couple of times due to very low voltage (fuel feed) settings, the pump got a bit of tallow or something in the gears and the windshield wiper motor stopped turning due to this extra mechanical load, no damage to anything and once I turned the voltage up a little the motor again turned. This can be eliminated a couple ways electronically, I am working on the simplest approach now, we will see how effective it is.
The burner flame did get blown out in yesterdays blizzard, wind gusts up to 45 MPH, I closed the flue damper just a bit and re-lit the flame, worked fine from then on but did put out just a tad more smoke than it did when more combustion air was being supplied to the flame, acceptable tradeoff. Had I not caught this flameout as soon as it happened all that would have happened is the pump would have kept feeding fuel to the dead burner, the bowl would have eventually overflowed the fuel into the bottom of the tank, this excess fuel would have dripped out the weep hole into the 3 gallon drip container (at a quart an hour this gives 12 hours to correct the problem before the drip container overflows). I had this happen one night, I woke up from the cold to find this condition, I poured the fuel in the drip container back in to the fuel supply tank, primed the bowl with a bit of diesel, lit the fire, went back to bed, no problem..
A flame monitering sensor could easily be added to the fuel pump motor control to turn the pump off in case the flame went out, could also ring an alarm or whatever.
Cost for heat -- Based on 5 gallons of used veg per day it is costing me around 75 cents/day to heat the house, same amount of heat from corn would cost around $5.00/day, fuel oil about $9.00/day, propane around 10-11 dollars/day (I now it doesn't directly compute based on BTU's but it seems to burn more efficient than oil), electricity would be around 13 dollars/day at the new higher rates around here.
Way to go Tim!!! Saving big time on heating bill, isn't that sweet!!! Why is it costing 75 cents a day? I assume you don't pay for WVO.
Did you make any mods to the Suntec or just running it at slow speed with the wiper motor? Are you using the standard output port on the Suntec or are you using the bleed port?
About the pump stalling, if you go to a higher torque gear motor would that solve the problem?
"A flame monitering sensor could easily be added to the fuel pump motor control to turn the pump off in case the flame went out, could also ring an alarm or whatever."
A CAD cell with a Honeywell RM8184 primary control will provide flame detection and shut off the motor. I have a good used one if you are interested and have something to trade.
Canola -- veg cost -- It runs about 15 cents/gallon for the veg that I run in the vehicles. This covers the cost of collection, filters, electricity etc involved with collection and cleaning.Thinking about this now the cost of the stove oil is likely less than this as I am not filtering it other than settling at 100 deg for 3-4 days.
In this weather I do have to run the 500 watt electric heaters in my settling barrels, they run about 30% of the time, haven't figured the cost since the local electric rate went up by 40% the first of the year (11 cents/KW now), probably still runs about the 15 cents/gallon due to this added cost.
Suntec pump -- Both of these fuel feed units are using model "J" pumps just because I had them (salvage yard treasures from last summer), they are stock pumps and I am using the bleed port as the output. Using the bleed as the output only requires the pumps to make as much pressure as is needed to push the fuel out of the open-headed fuel drip tube, this reduces the load on the motor to the minimum, it also gives you the max flow possible from the pump.
At these very slow rotating speeds the pump will not make ANY suction on it's input so the pump MUST be located lower than the fuel supply to insure the entire pump unit stays flooded with oil by gravity.
These suntec pumps are still not the ultimate pump due to there small gear teeth and the small restrictive inturnal pump inlet passage size, To keep the gears from jambing you need to screen the oil finer than a window screen size, this requires the oil to be above 60 deg or it won't pass through the screen because there is no suction generated by the slow turning gears. Running them without any screen will eventually allow something to either plug up the small passage or jamb up the gears. still looking for something better.
Motor -- Higher torque would do it but at an extra cost, would have to buy a much more expensive industrial gear reduction motor than the $5.00 junk yard wiper units. The wiper motors have huge torque when being powered with the full 12 volts due to there high gear reduction ratio, I am adding a bit of electronics that will pulse the motor with 1/4 second of full 12 volt power every 5 seconds or so, this 1/4 second will turn the output shaft about 1/2 rev, this is enough to move the pump gears several teeth so should do the trick. The model J pumps use a wierd broad flat-faced gear profile, this moves oil well but also causes the gears to jamb up much more easily than normal triangle shaped gear teeth.
I will eventually pick up a 1750 rpm model "A" suntec pump, these use normal triangular shaped gear teeth and the 1750 rpm units should move about the same amount per rev as the model J but be much less prone to this type of soft-gobs-of-stuff jamb-up, have to try one to tell for sure.
One nice thing about the model J pump is the shaft seal, this seal uses hardened polished steel against polished brass so there is no rubber or plastic involved, it should handle about anything, even biodiesel, probably even straight alcohol, without a seal leak problem. This should be the answer for the folks having suntec pump seal problems burning biodiesel in there high pressure gun burners but I have not seen it suggested anywhere.
Another option I am considering is to add a true tachometer setup to the pump/motor unit, this would automatically adjust the motor voltage to whatever is needed to keep the pump shaft turning at exactly the preset speed, this would compensate for about any type of fuel feed situation except for a true gear jamb situation, a safty circuit could be incorperated that would then shut off the power to the motor before any damage was done, could also trigger an alarm of some sort..
Tim, Where did you find out about the tooth profiles of the J vs A pumps? Would you have a manual for these pumps? I have a couple of J pumps and I think I have an A pump (a 1750 RPM unit from and old oil burner). I have not had them apart yet but will soon.
Now that you have your pot burner running well, have you considered using it to heat your WVO before settling? Wrap a few coils of 3/8 copper tubing on the outside of the pot burner and circulate the WVo with a Suntec till it is up to temp and let it settle.
If you start using these pumps you will eventually see the gear profile from opening them up for unclogging/cleaning.. I think I could do it in the dark now.
Check the "technical info" section on the Suntecpumps.com website (here), some of the literature shows internals of the pumps, the model J even has a trade name of "rota-roller" for the wierd profile.
Other heater -- Next changes are to try burning used motor oil, it is getting time consuming having to heat-settle-pump-reheat veg for these stoves. Used engine oil does not set up solid when cold and I could simply put a large multi-hundred gallon supply tank outside and eliminate all the cleaning, heating,and handeling.
Next heater test will likely be a syphon nozzle conversion to a modern Wayne furnace gun burner. This will be used to heat water in a somewhat converted vertical steam/pressure cleaner that uses a double wrap of schedule 80 1/2 inch pipe to heat the water, this coil of pipe is wound pretty tight so need a burner that puts out a lot less soot than a drip burner or the tight spaces between the pipe coils will need cleaning a lot. This burner can be automatically controled on/off more easily to keep the water at a more constant temp.
The hot water will be circulated to a large insulated tank, it can then be used to heat about everything, even the house.
Not happening this winter though, got to get to other projects, for a while at least.
oil cleaning process -- I originaly was spending a lot of time doing the same process as for the oil being burnt in the vehicle. Pour from cubees through window screen siev into settling barrel, water wash, warm settle for several days, circulate through filters for 48 hours, remove water using a flash evaporator- store in 5 gallon cans.
After reducing these steps over time I now simply pour the oil from the cubees directly into a settling barrel, no water wash, warm settle for a couple days, fill 5 gallon cans. This still takes a good bit of time but a lot less than before. The heaters will burn very wet oil with no indication of problems, I can't tell any reduction in heat output even though the water in the fuel is sizzling a lot in the burner and the chimney is outputting a good bit of white water vapor.
Biggest problem burning veg is the need to use 5 gallon cans that can be carried inside for melting. Next testing will be burning used motor oil, it does not go solid when cold so can be stored outside and piped inside, a LOT less work.
Truly fantastic work Tim. Thank you.
mathematical elegance -- desired result achieved with minimal complication
The weather has shifted dramatically here over the last couple of days, went from 15 inches of snow and temps in the lower teens during the day to today's afternoon temps of 49 deg f. I dropped the fuel flow to the single bowl burner down to .11 G/H over last night and the house temp was still 79 deg f, dropping it even lower today, it will be interesting to see how far down I can drop it and still have the burner stay burning reliably. The 12 volt wiper motor is now running on only 2.6 volts dc, this likely will be the thing that limits the lower end of the fuel flow, the 12 volt motor will likely stall once I reduce it's voltage even more. Once I find the low end stall point I will go to a pulse technique rather than a constant low voltage, feed the motor say 4 volts but only for a couple seconds out of every 10 seconds or so.
With the .11 G/H fuel rate there is almost no smoke detectable from the chimney, have to stand and watch for several seconds to detect it. With the .2 G/H rate the smoke is detectable if you look closely at the chimney but I have tried to see it as I drive past the house , I can't detect the smoke in a quick glance.
The combustion air amount makes a big differance in the amount of smoke and in how fast the bowl cruds up. We had a blizzard here for a full 24 hour period, had wind gusts up to 45 MPH, the burner blew out during the night of this storm so I closed down both the combustion air damper and the flue damper a bit, the next morning the bowl was severly crudded, 1/2 inch of ash/coal covering both the bottom and inside sides of the bowl, this was producing a good bit of smoke and the smoke was easilly seen from the chimney. I swapped in a clean bowl, opened up the combustion air damper about 1/8 inch, The flame yellowed up and the smoke is back to it's normal small amount, the bowl is in it's 4th day of use without cleaning, it does have a bit of buildup on the bottom of the bowl but none on the sides.
Tim, do you have any advice for me if I want to run a Suntec A2VA-7116 gear pump as a metering pump at between 5 to 20 psi adjustable? The pumps original spec is 3450 rpm 100 psi. What kind of mods do I need to implement? DC gear motor to drive it at slower RPM? using the bleed port for the output? Change the spring to a lighter one? Thanks!
Canola -- Don't think I would exactly call it a "metering" pump in your configuration, "feed" pump would more fit it's function, I think. I assume you are intending to use this pump to pressurize a needle valve for dfip feed.
First thing would be to change to a softer spring, this will take trying different ones. I am using this same pump onj the flash evaporator, it moves over 5 G/H at 150 pounds pressure using a 1/6 Hp DC scooter moter that turns about 800 RPM. Sort of a trade-off as if to use a direct drive motor or a gear motor, I think I would go with direct drive for the way you are using it, you only need a speed controlable gear motor if you are controlling the flow directly by the pump RPM as is the case when using it as a true "metering" pump (flow directly related to, and controled by, RPM). The pump does not make the motor work any harder once the pressure reaches the set point so about any motor will do, it only need turn fast enough to supply the amount of oil you need at the preset pressure but there is not much extra power used if it turns faster so the speed is not critical as long as it turns fast enough.
Bleed port as output -- Yes, This gives you max flow for whatever RPM you are turning the pump, put a plug in the normal "nozzle" output. You will also need to block the internal bypass ports that keep the pump from making pressure until it is turning at almost the full 3450 RPM. This has been discussed before in the flash evaporator discussion (here), the easiest thing to do is to remove the outer pump cover, (The screen is under this), remove the screen, remove the 5 screws holding the layers of the pump together, then remove the top layer from the internal smaller actual pump, replace the gasket under this cover with a home-made one with out any flow holes, replace the top layer and the screws. This forces the pump to start making pressure as soon as it begins to turn at even very slow speed.
You may want to remove the internal screen if your oil will be prefiltered, the screen limits the flow to only 3 G/H with fuel oil, thicker veg will flow much less unless you heat it to around 100 deg. Even with the screen removed I have to run a heat lamp on the outside of the pump casing if the house temp is below 60 degrees or globs of tallow can block the small internal passage into the gears. This is one of the problems with these pumps, especially if using them as slow turning metering pumps, the slow speed does not make any suction to pull the oil into the gears.
I have considered drilling another larger hole in the internal cover of the pump to allow oil to get to the gears easier but have not tried this yet, not even sure it would work due to the way the gears move oil against a fixed surface.
A couple other comments --
SS single burner bowl -- I originally stuffed the canister below the burner bowl with house-type fiberglass insulation, over a couple weeks this insulation sort of "melted" into a 2 inch tall crusty lump in the bottom of the canister so I removed the fiberglass completely, can't tell any differance. The burner bowl sets at least half way down inside the canister anyway, seems to be working fine using only the empty canister to hold the burner bowl.
House on a concrete slab -- My 24 X 32 ft house has a concrete slab floor, it took about 7 days before this slab came up to temp and quit sucking up heat. Once it warmed up the house got much hotter with the same amount of fuel being burnt, this happened pretty quick over about 12 hours on the 7th day. The slab has kept the house warm for several hours the couple times the flame went out, Now I undertstand why folks like heating a slab with internal water pipes, nice stable heat.
Mininum fuel rate -- It looks like 1/12 of a gallon/hr is about the lowest burn rate reasonable for this heater. This is at the very minimum voltage limit (2.36 volts) that will reliably turn the pump, it also seems to be at the point that the inefficiencies of this heater design soak up a lot of the heat.
I ran it for 24 hours at this low fuel rate of .086 G/h with no problem other than the flame blew out because I forgot to close down the intake air when I lowered the fuel rate, re-lit the burner and all was normal. At this low fuel rate the burner tank outer temp was only around 130 degrees F in a 70 deg room, this is much cooler than the 165 deg f when burning .1 G/H, or 270 deg f when burning .2 G/H, or 285 deg f when burning .22 G/H. I suspect that the low 130 deg f is because there is just not enough extra heat from the small flame to heat the tank, most of the heat is likely going out the flue pipe, even the flue pipe is not all that hot, I can hold my hand on the pipe above the half-closed (set to 45 deg) flue damper for a couple seconds before it gets to hot to hold, below the damper I can only touch it for a fraction of a second.
.086 G/H of veg oil is still making around 10,000 BTU/HR of heat and the stoves outer surface is at 130 deg f, I don't have any idea how to relate this to efficiency but it does seem to indicate that the stove wastes something like 5-7 thousand BTU's/HR just to keep the stove itself hot enough to begin heating the air around it.
The outside temps dropped down into the lower 20's f during the second night burning at this same low fuel rate of .086 G/H, the inside temps dropped down into the high 60's. Sometime during the night the wiper motor stalled and the fire went out. When I woke up the house was down to 60 deg. I slowly increased the voltage to the wiper motor and it began turning again at 4 volts, I assume the motor stalled due to some oil solidifying in the gears as the room temp got cooler, this caused just enough extra load on the motor to cause it to stop turning. The new motor control that pulses the motor with the full 12 volts for a half second every 10 sec or so should eliminate this stall problem, just have to get around to building it.
It look like the lowest reasonable fuel rate for this specific heater in this specific house is about 1/12 gal/hr (2 G/day) to get usable heat from the stove. burning at 3 gallons/day has worked just fine with nightime temps in the 20's f and daytime temps in the mid 30's f.
This burn rate -VS- outside temp -VS- inside temp data gives me a good idea where to start in designing a thermostatic control to automatically control the fuel feed rate to hold the house at a preset temp.
As the outside temps get warmer I suspect I will only burn the stove during the cooler nights, it will be a tiny bit more hassle lighting it every evening but it only takes a couple of minutes so no real problem.
The snow drift keeping me from the barrel of Used Engine Oil is about melted away so I will start some testing burning it in the near future.
Cleaning the burner bowl -- I went 5 days without cleaning the bowl while burning at the low fuel rates, this was at least one day too long. After five days the bowl had formed a 3/8 inch thick crust across the upper opening of the bowl about half way up. There was only a hole about 1 1/2 inches in diameter in this crust, this reduced the amount of air getting to the flame and also the amount of hot surface area available to vaporize fuel. Both these had to affect the efficiency of the burn and was likely producing less heat and more smoke than a clean bowl. I wiil switch to a clean bowl after no more than 3 days, probably less, from now on.
I still havent finish mine due to business at the shop is good currently, thank God... anyways i just keep thinking that on mine I will use a pressurised fuel tank for supply instead of a pump of any kind.. I hope to find that I can presure up a 5-10 gallon tank by using a adjustable regulator at say 10-12psi on a tank of this size it will need a very small air compressor setup that should rarely need to run itself , say a compressor with a 1/2 hp motor on a 10 gallon tank that will develop 70 psi common and cheap... then for rate control a solinoid valve in line pulsed open in a varied rate to increase or decrease heat out put, NO GEARS NO UNDERPOWERED MOTORS etc What am I missing here, I know Toms heaters work so maybe i should just follow suit?? pictures of my stove and burners are posted on the thread about increaseing heat of burners...... Tigman
wvo is no longer waste when we harness it's power!!!
my bad Tims heaters, hope you dont mind being called Tom...Tigman
wvo is no longer waste when we harness it's power!!!
I am still reading but don;t want to forget so here it is; to control oil flow vs pump voltage wouldn't it be simpler to set up a by-pass valve that would act as a type of return line ?
The pump could pump it's little heart out but with the by-pass valve (small ball valve) returning the uneeded fuel back to the tank you could reliably control flow, no ? Why try to control the pump when all you need to do is control the flow ?
I use this principle for my drying tank where the clear water pump is way too much for the need so I have a ball valve hooked up to take up the slack/pressure while leaving the pump at full throttle.
You could regulate the pump to a comfortable level but then let the by-pass take up the overkill and return it to the tank.
Because I intend to build an electronic thermostat that will automatically adjust the oil flow to keep the room temp at whatever temp I preset it to.
I think the easiest way to control the fuel feed is by using this true "metering pump" approach, the speed of the pump directly relates to the amount of oil going into the heater and it is easy to control the speed of a DC motor, it also takes only the minimum of electric power needed for any specific heat output of the stove as the electric motor only runs as fast as is needed rather than wasting power just circulating oil. This only makes a differance if you are running on a 12 volt DC battery backup system and you experiance frequent power outages, I do, been several already this winter.
OK, I get the auto contro thing, but wasting power ? So very little that is it negligeable, IMO.
In any case couldn't the returning fuel be used to warm up the fuel tank in the same manner the return on an engine does ? Maybe not an issue with UMO but WVO is certainly is, unless some other source of heat (energy) is used.
I am not trying to be difficult, but see if my ideas would work and be as reliable and self propagating as possible.
Using your Suntec with the windshield washer motor set on a low, but stable setting would guarentee reliability but may be too much fuel in certain applications so the by-pass could be used to control the flow returning the warmed up oil to the tank and thereby slowly increasing the fuel supply's flowability.
The question really is: Is this going to work for me? I know nothing about the subject other than deductive reasoning based on all your research and revolutionary upgrade to what will surely turn out to be a simpleto build and operate furnace that almost anyone can put together to reduce heating costs. I am impressed, although I need to work around any high tech stuff I don't understand, automation being one of them.
What you really want is a servo motor with a 0-10 volt DC signal for speed and a temperature controller with a 0-10vdc output for temperature.
That would solve your temp control problem for sure.
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I'm missing where exactly the oil would be getting warmed before your bypass valve in Tim's design?
mathematical elegance -- desired result achieved with minimal complication
I am still toying with the principle but something along the way of a line running inside an iron pipe along the outside of the heater.
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