Biopowered - vegetable oil and biodiesel forum
General => Alternative heat and power => Topic started by: photoman290 on November 07, 2013, 09:52:24 PM
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i have been doing some experiments to try and create something a bit safer to control my waste oil burner design. i managed to find an old woodburner big enough to be able to fit a waste oil burner into. as this will be be in a house with different people using it the needle valve idea is too unpredictable for other people to use safely. works fine for me,but i am sitting next to it most of the time. plus i never leave it on when i go out. the problem is if you turn it up and forget to turn it back down the pot fills with oil and it gets very hot. it takes about 10 minutes to die down if that happens.
so i have been experimenting with a 12v peristaltic pump. i am using a battery charger with high and low settings so i can adjust the speed. first results are good. i used some manky old oil with water in it. pumped it quite easily. i will get a pwm controller from ebay, could make one but they are cheap enough. this will hopefully give me more control so i can set the flow low enough that the pot cant be overfilled. of course you could turn the pump on and not light it, but that would be highly unlikely.
the problem with the needle valve is it needs well filtered oil to work. it gets blocked very quickly on unfiltered oil. the advantage is is doesn't need power. this shouldn't be a problem in the house. plus it should run for a long time on a battery if they do get a power cut.
more details when i get the controller,but so far really pleased with the way it is going. if i don't have to filter the oil too much that is a real advantage. i have 400 litres that has been settlling for a few months so will try that first.
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Tidy. I'll be interested to see how it goes. Nearly got my thermal store up and running now, so will be contemplating a WMO heater for it next.
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will let you know how i get on. it looks as if peristaltic pumps have a good suction head. 25 feet or so. the plan is see if i can get it to suck straight from a 200 litre drum about 10 feet away from the coach,and about 4 foot below the height of the burner. i will use copper tube for the run from the drum and silcone for the last bit. if not will just put a 25 litre drum under the coach and feed though the floor.
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Hmmm, I wonder if there are any peristaltic pumps in the dishwashers I've got kicking about? Seems to be one of their uses.
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Hmmm, I wonder if there are any peristaltic pumps in the dishwashers I've got kicking about? Seems to be one of their uses.
i thought of those as well. the problem is they are ac fixed speed. you want a dc one so it is a bit easier to adjust the speed. there is a nice one one on ebay at the moment. i thought about it but 2 litres an hour is a bit low for what i want. good pump though.
http://www.ebay.co.uk/itm/RS-Peristaltic-Pump-330-812-2-Litres-Per-Hour-Physics-Bio-Fuel-BREW/121210091709?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D2553903456920531473%26pid%3D100033%26prg%3D1011%26rk%3D1%26rkt%3D4%26sd%3D121210091709%26
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I think you can get AC speed controllers off ebay cheap too.
(well, i know you can get them, i just dont know how much they are)
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I know some people have used oil pumps scavenged from cars or 2 stroke m/cycle pumps running from w/w motors on adjustable voltage controllers, I don't know what they would be like for drawing oil over a distance though.
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I think you can get AC speed controllers off ebay cheap too.
(well, i know you can get them, i just dont know how much they are)
the trouble with ac speed controllers when using them with synchronous motors is the motor tends to overheat. ok with brushed motors like drills and vacuum cleaners. i could be wrong but that rang a bell somewhere. they are about the same price as dc controllers. dc peristaltic pumps are also a lot cheaper than the ac ones.
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couldn't you just fit a bypass in the outlet pipe, and strangle the last bit of pipe to slow the flow? Be easier than messing with controllers.
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couldn't you just fit a bypass in the outlet pipe, and strangle the last bit of pipe to slow the flow? Be easier than messing with controllers.
the trouble with doing that is you introduce an extra restriction in the pipe.if there is crud in the pipe as the rollers go over it it will squeeze any crud and push it down the pipe. if you restrict the end of the pipe you will limit the size of particle somewhat. when i have repaired the dishwashers at the cafe one of the things that happens is the detergent blocks the pipe. they normally have a filter on the end of the pipe. if i add a bypass it is more places to get blocked up. the controllers are only a few quid anyway. you want some control over the flow rate. if you use a bypass you will need a valve. a controller with a knob is a bit simpler.good idea though.
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light dimmer?
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light dimmer?
the same thing but in a plastic box.
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a further update on progress so far. i have a test setup now. very basic. peristaltic pump sitting in 5 litre container of old manky engine oil. battery charger, stop watch. i have a bit of heat resistant tubing 4mm dia or so with a bit of 6mm brake pipe just stuck in one of the air holes in the burner.
i am trying full power and switching the pump on for 5 seconds off for a set time. the reason for 5 seconds is because there is a board on ebay with a fixed 5 second on adjustable delay f up to 60 seconds with a on board elay. seems the simplist way to do it. so far 5 secs on 20 secs off seems to produce the best results. will order a board and experiment a bit more.
what i have noticed about using a peristaltic pump is the viscosity doesn't matter so much. as long as the pump is powerful enough to lift to fluid it will deliver the same quantity every time. i am still using heating oil to start the burner using the drip feed. may start on engine oil but haven't tried yet. so far results are looking promising.
next experiment is to see how far it will pump. hopefully from my oil stash about 15 feet away. it is lower than the floor of the coach so i wont get a siphon effect. i need to drill a hole in the coach wall first.
link to timer kit.
http://www.ebay.co.uk/itm/VELLEMAN-KIT-MK111-MK111-ADJUSTABLE-TIMER-WITH-RELAY-/360754807950?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item53fea9848e
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Given how temperamental engine oil is to burn, would it work with melted glycerol? I get the feeling from the BBB that glycerol doesn't carry so much energy as engine oil but it certainly seemed to burn more evenly. And there are plenty of people that want to get rid of glycerol (though you've have to avoid any with water in).
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engine oil seems to burn as well as kero in my burner. water isn't a problem. the stuff i am using for testing is really manky with water in it. burns fine. if someone wants to send me some glys i can experiment. 1 litre would be enough to find out. i think if it goes thought the pump it will burn. KOH based would be best as the NAoH stuff might block the pipes when it goes cold. could flush it though with some kero. how hort does it need to be to flow?
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how hort does it need to be to flow?
That will depend is so many things, type of feedstock, amount of catalyst used in the reaction, % of meths and so on.
It may be worth doing some tests on mixing it with the WMO.
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if someone wants send me a litre or 2 i will experiment. nothing like sitting next to nice warm fire and experimenting with differant combustibles. ;D
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Bob, I can send you some KOH based glycerol if you like.
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hi jules yes please about a litre or so will be enough to test the theory. will pm you my address.
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Wouldn't you prefer a couple of hundred litres, just in case it doesn't quite work first time :)
I got your U2U with the address so will get some sorted out and in the post down to you.
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Wouldn't you prefer a couple of hundred litres, just in case it doesn't quite work first time :)
I got your U2U with the address so will get some sorted out and in the post down to you.
couple of hundred litres would be great. i am coming past yours in about 3 weeks. will see how the experiment goes first though.
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a progress report on my WMO burnere project. got the timer circuit built and tested. all working fine. i have it controlling a peristaltic pump. i am using a mixture of 75%wmo 25% kero for now so i don't overload the pump.
i am sitting in front of it and playing with the mark space ratio to get an idea of the range i will need. the idea is to have one control knob that varies the pause time. all seems to fine at the moment.
still waiting for the mains powered pump. so i have the system running off a 12 volt 4 amp power supply for testing. once i am happy with it i will see how much power i need for the relay board and just make a 12 volt supply that runs off the 240 line to the pump motor. hopefully i can fit this inside the pump casing for relative safety.
i was going to use an ssr but think i will stick to mechanical relays,and fit a relay socket on the board. the reason is ssr's tend to fail short circuit which i don't want to happen.
i am wondering if anyone knows of a fully mechanical thermostat that works with liquids? the fewer contacts to wear out the better. something like a gas thermostat but for liquids. the idea is to fit it between the oil feed and the pump so if the temperature gets to high it will reduce the oil flow. i know you get oil shut off valves that cut the oil flow in case of a fire. something like that but variable. not expecting it to control the flow to a great extent just cut the flow down or off if the relay points stick., or the circuit fails. a fail safe really.
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I think Danfos do one. Its a bit like a TRV but fits to a pipe and has bulb which is located in a pocket. I found it when looking at fitting a boiler to the log burner ... but it's frighteningly expensive!
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Could you adapt a controller for an central heating boiler?
They're cheap, adjustable, and you could vary the temperature range by moving the bullet bit further from the heat source.
One of these.
http://www.ebay.co.uk/itm/HOT-WATER-BOILER-HEAT-THERMOSTAT-ALL-RANGES-/280580719207?pt=UK_Home_Garden_Hearing_Cooling_Air&var=&hash=item4153ea0267
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i have plenty of those thermostats. they only switch the poer on and off around a fixed temperature. usually around 20 degrees differance on the ones i have. i want something that progressively reduces the oil flow as the temperature rises and increases it as it cools down. i can get one of these which would work if i cant find a variable one.
http://www.ebay.co.uk/itm/3-0m-x-90C-Remote-Acting-Fire-Valve-for-Oil-Fired-Boilers-/261319998606?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item3cd7e2bc8e
at least one part of the system would then be safe. :o
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I see what you mean.
Thermostatic valve off the bottom of a central heating radiator?
Not quite sure how it would work, but maybe something to ponder upon.
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looks like you can buy capillary TRV's but a bit pricey and not much range, 10 degrees to 30 degrees but a start. the range is a bit small but its a step in the right direction. maybe covering the bulb with something to get the range up may work. will do a bit of probing with the thermocouple thermometer. and not sure how they would cope with dirty oil.
just had a thought, i could fit it to the output side of the pump and feed it back to the oil reservoir. that way i don't have the pump running dry and i have a bit of pressure so i could fit a filter before the valve if i find i need one.
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An automatic window adjuster for a green house has big range, and a lot of travel, and it's adjustable. They are also quite powerful.Obviously, the temperatures it is designed to work at are far lower, but you could mount it at an appropriate distance from the burner.
You could rig up something to strangle the pipe, I would say it would be powerful enough to move the lever on a ball valve.
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yes i did think of using one of those. there is a "spare" one on debs greenhouse. that is plan b.
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found one of these, but at that price i could move somewhere warmer for the winter. like portugal.
http://www.ebay.co.uk/itm/Sterlco-Sterling-CR-151-F-Temperature-Control-Valve-Self-Modulating-3-4-NPT-/221206285975?pt=LH_DefaultDomain_0&hash=item3380ec0e97
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http://www.danfoss.com/North_America/Products/Categories/List/HE-HEC/Control-Valves-and-Temperature-Controllers/AVTB/b5b85908-fa32-45ff-80bf-34e08c5a3a04.html
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thats the sort of thing i was thinking of. just have to keep an eye on ebay for a cheap one.
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Wouldn't hold your breath ... I bet they don't come up that often, but good luck!
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been having a think about poosable failure modes and come up with a couple of options to make the burner idiot proof,or as near as i can anyway.
failure mode one:
someone turns it up too high and the oil fills the pot faster than it is burning. i think one of these will sort that possibility out. cuts off the oil supply by diverting it back to the tank. no oil, fire goes out.
http://www.ebay.co.uk/itm/KBB-Teddington-2-metre-90-degree-fire-valve-C90-2M-/141115539608?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item20db244098
failure mode 2.
something goes wrong on the timer board and the pump continues to pump oil into the burner. thermostat cuts power to the pump. no oil, fire goes out.
http://www.ebay.co.uk/itm/TH11-LINCAT-FRYER-HIGH-LIMIT-THERMOSTAT-SPARE-PART-/140421388453?pt=UK_BOI_Restaurant_RL&hash=item20b1c458a5
not sure which one should trigger first? i think the oil feed, as the oil tank will be below the pump so no chance of oil flowing to the burner if the pump stops. if the electronics fail the pump could carry on pumping and overfilling the burner.
don't think either of them are adjustable so will have to experiment on best position to place the capillaries.
of course this means the fire goes out and will have to be relit, but variable valves are expensive and hard to find. the original idea was to let the burner die down and then fire up again once it has cooled down. if someone turns it up too high and it trips they will have get cold waiting for it to cool down before relighting it. that will teach them not to turn it up to high next time ;).
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just won this thing on the bay. looks like i might be able to do something with it. looks heavy duty enough looking at that spring.
http://www.ebay.com/itm/GM-VINTAGE-TEMPERATURE-SAFETY-CONTROL-SWITCH-by-TEDDINGTON-APPLIANCE-CONTROLS-/221313582042?
range is a bit low but should be able to find somewhere for the capillary. it has all the important bits to be able to control a valve.
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Well that was cheap enough, and probably far better quality than new stuff.
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yes anything diecast and painted in stove enamel is always a good sign. looks like it might be ex MOD from the label.
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just won this ...
As no on else was daft enough to bid, surely the term should be "just bought this"?
... only a thought.
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just wasted 10 quid on yet another piece of possibly useless tat just because i liked the look of it. had a girlfriend like that once, she cost a lot more that a tenner though. is that accurate enough for you?