Super low buck filtering

[Josh Carmack]

I have never had a fire that I am certain of, and I have gotten my oil hot enough to literally have the oil residue smoking on the drum sides and the pump and valves. I suspect I may have had a fire, but I am not sure.
I left for town one day with 7500W (2000 + 5500W ) of heat running on a 3/4 drum. I got involved in buying parts and trying to order something weird and hard to find I wanted for my setup. Came home 2-3 hrs later to find smoke pouring out of the barn. Realizing what I did I ran in the barn expecting to see a fire, but only smoke pouring out of the drum. There was oil splashed everywhere from the bungs.

One of two things happened, there was water in the oil, which is very possible, because before this day I only heated enough to get the oil up to around 180 200 so it would flow well. If there was a lot of water in the oil it would have at some point boiled violently causing the oil to be splashed upwards out of the bung holes.

Scenario two says I had a fire, and is the most likely scenario as I heard a thump-whoosh a few times and each time smoke would violently shoot out of the bungs. I figure in the beginning, the oil flashed, but very quickly ran out of oxygen. The cycle repeated as the burnt fumes exhausted and new cooler air entered until a flammable ratio was met again. That would explain the several thump-whooshes until it cooled off some.

That was the time that the oil got hot enough to melt and dissolve the plastic fittings in the drum as well as the plastic insulator on the end of the heater elements. That is one of my best running and best flowing batches I have ever had, and the batch that taught me to heat all my oil til it smokes.

 

[Josh Carmack]

Once the heater is submerged it will self cool by convection. Oil unlike water has a fairly large expansion coefficient, and will rise very quickly off a hot element submerged. I have burnt out a lot of the cheap high watt density elements, but an ultra low watt density element lasted several months, and would still be going if I hadn't turned it on dry one day. I don't circulate when heating because the oil does a fine job on it's on. I have found that batches with lots of water in them will shorten the life considerably when compared against dry batched using the same type of element.

I will admit, using 5500W is wasteful, as a LOT of heat is lost to the air surrounding the drum. With my new design that I am slowly building as I can afford, it will use either a real coffee maker heater, or one that I build myself using the same idea but my own nichrome wire wound around a copper tube. If I build it myself I'm going to shoot for 500W or perhaps a little less. I want just enough heat to heat about 10 GPH to around 250/300F. I haven't sat down and worked the math for it yet, so I don't know how much wattage I need. That slow hot trickle of oil will be fed into my motor driven fugeavertor (torque convertor fuge).

 

[Brad S.]

Josh do you think a water heater blanket would work on a 55 gallon drum, hopefully those are somewhat fire retarded.???
To retain heat in the wmo.....

 

[Josh Carmack]

I have a lot of lofty ideas for my processor, I have been meaning to wrap it in fiberglass for over a year. Not so much as a fire retardant, but to help keep heat in. I have tried to burn old fiberglass batting insulation on more than one occasion. The backing will burn, but the matting just melts and nothing else. I guess a water heater blanket will be more convenient, but is only as good as it's rating. I was planning on wrapping it with R13 and then covering that with plastic and using gorilla tape to seal it from spills wetting the batt and lowering it's efficiency.

 

[Brad S.]

You talked about using smaller wattage heaters, makes me think of some heaters I've seen at the local farm store.

You must be registered for see images

A element like this is kinda what comes to mind, usually they are not more then 500w or so.
The problem I see with something like this is sealing the entry point, I know they are threaded and have a rubber washer to match.
Kinda like your idea of the submersible type element, because of wmo "self mixing" Like this????

You must be registered for see images

Is there any concern that wmo would be corrosive to the cord??? over a longer period of time..???
(I know thats kinda hard to answer, but just thinking out loud.)
With the smaller wattage elements, how much longer does it take to warm up the mix???
I do like these ideas of yours, gives some ideas on my own setup.

 

[Josh Carmack]

I use Carol brand "SJ" cord to feed my elements, and it has most definitely deteriorated over time. I have had to remove about 6 feet from the end of the cord in two years time. I supposed, it's the heat and oil, although SJ is supposed to be oil resistant. I'm pretty sure that rating is at room temp, not the few hundred it has seen more than once.

The heaters you show are a neater way of heating, much nicer than my method of drop a water heater element in the drum bottom, but they are way off base from what I'm talking about.

Years ago I disassembled a coffee maker as a curious child. What I found was nichrome wire wrapped several turns around a silicone tube with the coils being fastened to the hot plate simply using a form of epoxy. A simple check ball allowed the boiling water to exit in the proper direction.

I'm intending on purchasing a 10 dollar coffee maker and gutting it with the hopes it will still be designed the same way 30 years later. If it is, I will replace the silicone tube with copper and give it a try at heating a very slow trickle of oil. If it isn't the same design, or simply won't work I am going to purchase a few feet of nichrome and wind my own inline heater. That inline heater will feed my single pass fugavetor.

 

[AcIdBuRn02ZTS]

Why not use the threaded water heater elements? I am planning on doing something simular... I'm getting ready to move so I'll be changing things up a bit. I want to swap my plastic settle drum for a steel drum with bungs... I'll flip it to put the bungs on the bottom and bush the bungs down to water heater element sizes. Those elements last for YEARS in water... I wouldnt think oil would effect them much.

As for the fire you had... I had a simular experience welding a bung into my pick-up tank... the drum was empty but still had residue in it... after a short solid bead, the tank started huffing and whistling like a tea kettle out of the ports... I thought it was going to explode... melted the plastic fittings out of all the ports and burnt the paint off the drum.

So.. anything wrong with using the replacement water heater elements or does the oil do a number on em'?

 

[Josh Carmack]

Thats exactly what I am using, instead of threading them in, thats one more chance for a leak, I drop them in from the top. The cheap ones don't last long, the ULTRA low watt density ones do ok. Oil has a lower heat capcity, lower heat density. While it does expand greatly compared to water, it moves heat away slower. That causes the heater to see more heat in itself. As long as you don't heat beyond boiling temperatures they do very well.

If you have water in the oil, and heat beyond boiling is where the elements begin to fall very short. If there is a large amount of free or dissolved water it causes the elements to carbonize.
If even it only has dissolved or emulsified water, as the water is flashed to vapor it starts "bumping". Bumping can be violent and causes pitting on the elements casing. As the bumping turns into flashing then you get carbon buildup on the elements which makes them inefficient at heat transfer and eventually causes a hotspot burnout.

If you have ever heard a deep fryer heating up used cooking oil that high pitched popping you hear is bumping. It's water flashing to steam violently and then collapsing causing cavitation. On some wet batches I have heard it bump hard enough to actually vibrate the drum.

Something to keep in mind also, while the threads on a water heater element are 1", they are 1" NPS, and not 1" NPT, the difference being National Pipe STRAIGHT, and National Pipe TAPERED. I was able to make an element seal in a 1" bushing, but I had to mount the bushing in the vice, and use an axle nut socket and 1/2" breaker bar to get it tight enough to bottom the gasket against the fitting. Your typical stamped steal element socket will not handle that much torque.

If you don't heat above 210F you should have no problem getting a few hundred hours out of an ULWD or LWD element.

 

[AcIdBuRn02ZTS]

Good deal. When I set it up, I can cut my own bushing if need be... but I'll try to find the proper adapter or cut a port from an old water heater and weld it into the side of the drum.. might be easier to go that route actually.

 

[Josh Carmack]

You can buy a flange element adapter at the hardware store, it designed to convert a flange heater tank to use threaded elements. While you would need to slight bend the flange adapter, it will be already threaded to save some lathe time. About 8 bucks last i saw one.

 

[Josh Carmack]

I have never tried to find one, but I'm betting an NPS tap can be found online as well, then you can just ream the threads on a tapered fitting.

 

[Shadetreemechanic]

My centrifuge setup is the flipped barrel with water heater element threaded into the bushed bung. It works fine with no leaks.

 

[Josh Carmack]

I would bet that it comes down to the manufacturer of the element, The first one I screwed into a bushing went in pretty well and didn't require much to get the oring to bottom out on the fitting. Element #2 required a vice and a breaker bar to get it to run down. I never tested to see if they would leak without bottoming the oring out. It's very possible they will seal without bottoming the oring out, it should also be mentioned that the oring is "supposed" to be captured by a landing groove to keep it from deforming. I would assume that a good snug tightening will suffice since oil oil is quite thicker, and we are not trying to seal out 30 to 60 PSI.

 

[Shadetreemechanic]

I would assume that a good snug tightening will suffice since oil oil is quite thicker, and we are not trying to seal out 30 to 60 PSI.

I have two heating drums that I use for dewatering. On those I simply drilled a hole in the side of the barrel the same size as the element threads and threaded a lock ring from electrical conduit to the element threads on the inside of the barrel and tightened it until the barrell deformed and flattened around the element gasket. One has never leaked a drop in four years, the other seeped just a little when new but doesn't leak now. Because there is no pressure it seems easy to keep them from leaking.

 

[NTOLERANCE]

You talked about using smaller wattage heaters, makes me think of some heaters I've seen at the local farm store.

You must be registered for see images

A element like this is kinda what comes to mind, usually they are not more then 500w or so.
The problem I see with something like this is sealing the entry point, I know they are threaded and have a rubber washer to match.
Kinda like your idea of the submersible type element, because of wmo "self mixing" Like this????

You must be registered for see images

Is there any concern that wmo would be corrosive to the cord??? over a longer period of time..???
(I know thats kinda hard to answer, but just thinking out loud.)
With the smaller wattage elements, how much longer does it take to warm up the mix???
I do like these ideas of yours, gives some ideas on my own setup.

Brad - what farm store had the second heater you posted?