been playing

[photoman290]

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.

[greasemonkey]

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.

[photoman290]

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.

[greasemonkey]

Hmmm, I wonder if there are any peristaltic pumps in the dishwashers I've got kicking about? Seems to be one of their uses.

[photoman290]

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

[julianf]

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)

[Chug]

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.

[photoman290]

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.

[greasemonkey]

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.

[photoman290]

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.

[willbuild]

light dimmer?

[photoman290]

light dimmer?

the same thing but in a plastic box.

[photoman290]

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

[Tony]

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).

[photoman290]

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?