Listeroid-air in pump

[Devo2]

I keep getting an air lock in my fuel pump,I have 3 runs of copper against the exhaust wrapped in metal tape. Could this be to much much heat causing some boiling or something?

It runs good until it gets hot then it surges bad-I pull the screw & the pump is full of air.

Devo

[bj]

As it runs well until hot, probably vapor locking.  Too much heat.  Some kind of heat insulation between exhaust and copper
should help.  Air space alone might cause a hole due to vibration wearing through the copper.

[bob g]

if you are heating the fuel i have to assume you are burning veggie oil?

if you are burning veggie oil, or you cutting it with regular unleaded gas?

if so you will have to limit the amount of heat, as gasoline will vapor lock quite easily.

bob g

[BigBreaker]

Heat pipes are a good way to limit heat transfer.  Once the "cold end", the end heating the oil, is hot enough the pipe will stop conducting any more heat.

[damian]

Only if set up carefully so that at the point you want to drop heat transfer from phase change heat transfer to conduction transfer all of the working fluid has boiled and is in a saturated vapor condition.  I've played with it for this application and it will work using water as a working fluid, which will work best, of course, if it is not somewhere that it will freeze.

[Devo2]

Mostly straight veggy oil-no gas at all, a little bi of diesel left in the tank, like 10%.

I am going to try taking them off the exhaust pipe & see if it helps.

Thanks fella's

Devo

[BigBreaker]

Damian - I wrote out a whole paragraph on how to make the actual heat pipe and then deleted it.  The reason?  If my post is necessary for someone to build the heat pipe, then the builder runs a non-trivial chance of killing themselves with a steam explosion.

But yes... in short...  get your copper tube, close one end, fill with water, mostly close the other, boil off the water until the steam is slow, remove heat, close that second end too.

Now you have a heat pipe that will top out just over 100C, which is nice temperature for veggie oil.  130C would be nice to boil off any water in the oil.  You'd want to close off the tube with a bit more vigorous steam but weigh the tube dry, filled with water and after sealing in the (remaining) water.  A little math will tell you if you have the right amount of water.  Again... you don't want a steam explosion.

Of course you need the hot side low and the cold side high for a heat pipe like this.  It will work better if you score the inside of the tube with axial grooves.

[bob g]

what you are describing can only be referred to as a stick of dynamite!

heat pipes are not "filled" with any working fluid!

actually it takes very little water in a heat pipe for it to work properly, and if you are looking for 100degree centigrade heat
one ought to look into some other working fluid with a higher boiling point in my opinion.

my advise is to be very careful working with heat pipes, and do some study before you build one.

bob g

[BigBreaker]

And this is why I didn't write about the heat pipe...

If you keep the heat reasonable, and leave a gap in one end of the tube it's safe.  If the steam is shooting out of the tube like rocket, it isn't.  If the gap is so small that a metal burr can plug it, it isn't safe either.

Yes, you will be boiling off almost all of the water.  Water expands 1600 times as steam, so 1/1600 of the volume of the tube, it water, will boil it all off with a peak pressure of 1ATM (0 ATM relative to sea level).  That is a small amount of water!  Consult a vapor pressure table for water to calculate other pressure temperature trade offs.  Not that copper gets weak at pretty low temperatures.  Consider how hot your exhaust can get and how much pressure that will create in the pipe.  Sealing the pipe with solder will create something of a blow plug.  The idea here is to make a vacuum heat pipe without a vacuum pump and fittings.  It will also perfectly calibrate the cutoff temperature for heat transfer.

I guess you could just keep adding a few drops of water to an unvacuumed heat pipe until you get enough heat flux but it will not start conducting until 100C.  That's not the end of the world.  The vacuum version has the advantage that it has zero net pressure at 100C and only small positive as temps increase.  Too much water makes that stick of dynamite, so be careful.  Unvacuumed pipes start at 1ATM and it goes up from there.

[Bruce S]

Devo2
First I do not have a listeroid, wish I did, but I do have a diesel and what you described is something I just helped an Aussie visiting St.Louis, was that you?

He has a very sweet setup on an 84 240D, he runs straight WVO in it and while talking about the differences (Met him at HF of all places) in Bio-D and SWVO he has the same type of setup and has the same type of problem in the summer here.

Answer is your oil is toooooooo hot!! get some fins make them out of old TIN soup cans or something and get the tubes off the exhaust.

The oil really should not be getting over 110F NOT 110C BUT 110F and 140F any water in left in the oil will begin to steam, this is the actual point of where I get my oil when getting it ready to become Bio-D. I bring my oil up to 140F and leave it there for a good 30 mins. Then do the fry pans test once it has come back down to 90F if it sizzles it gets reheated until it passes the fry pan test.
Anyway, we (HE) bought enough stuff from HF to reroute the incoming WVO around the 300w heater that he now does not have the problem anymore.

Hope this helps;
Bruce S
PS how many filters to do have ? are you letting it run with gravity fed fuel? might think about a smallish 12V gas fuel pump, that'll help. YES gas since the diesel ones cost more and warmed oil will flow through them just fine in a pull fashion.

[Devo2]

Thanks Bruce(it wasn't me you met,. I live in Canada in Ontario ). The pipe was also shaking like crazy when it was taped tight to the engine , could that contribute to the air lock? At any rate I removed the tape & put a little space between the tube & the exhaust & it seem to be ok.  I could let the oil hit my skin before as I bled the system when it was on the exhaust & it was darn hot but not to the point where It would burn my skin instantly or anything.

I wonder if the inline vibration was causing trouble.  I am gravity fed , 1 inline hydraulic oil filter after the tank -3 micron

Devin

[bob g]

where does your return line go to?
if it does not go back to the tank, but rather back to the filter you are asking for problems

the injector fuel return often is aireated, and will only add this air back into the suction side of the pump
if that line is not taken all the way back to the fuel tank.

bob g

[Devo2]

I had plugged it but came out the next day & the plug had come out-it was dripping on the floor :-) . Hey Bob are you the fellow that was into UPS's for computer back up? If so I have some questions about that as well.....

Thanks fella's

Devin

[bob g]

i might have been that fellar...

as for plugging that return line, don't
that will cause your air in the injection problems
the return line must be connected and return to the tank, or at least to the day tank
and not blocked, plugged or return to the filter connections

bob g

[Devo2]

Thanks for the help Bob, I have been coming across UPS's like crazy lately ,you have any experience with reducing the power on standby on the 3000XL APC's?

I have a huge one(ups lol) that is 5 or 7000 watts pure sine wave that even the grid is filtered through to keep it perfect, I was wondering if I shoud be feeding it with the listeroid & then the house to take the "bumps" out of the power... Maybe I should start another thread with progress with these things? I wish I had schematics to unhook every unneeded thing & run a solid on off instead of a relay or whatever it is & just flip the 3000's on when needed so there is no standby drain. 

Devin

[bob g]

i was never successful in finding a schematic for the newer and larger apc ups units
your thinking of using a relay to switch them off when not in use seems like the best approach to me.

i pretty much gave up on them when i got 30 plus kwatts of exeltech mx rack mounted inverters about a year
back.

bob g