Hi all,

Did some more work this weekend, but helped my friend with his truck as well, so I didn't get to do as much as I wanted.

I've decided to plumb the venturi pipe into the true lower element. See the pics below. The first one is a pic w/ two six inch, 3/4" pipes w/ a bushing in between. The leftmost pipe and the bushing will be welded together and screwed into the heater element hole:



However, after reading some things about eductors and their restricted outlet, would it be better to weld/plumb a 1/2" pipe? Pic below:



While the pipe outlet wont enter into the oil, would it help w/ mixing if I crimped the pipe's end?

I also worked on my dewatering/settling barrel. It's the one thats going to sit on the cart with the processor. I purchased two boat 4" deckplates whose openings allow my jean and sock filters to fit perfectly. Then when I am reading to heat things up for dewatering, I close the screw in clear deck plates and cover w/ insulation:



I affixed it down w/ that welder's glue, some self tapping screws, and some silicone. Here's what it looks like w/ a sock filter in it:

[IMG][/IMG]

I also welded in two new fittings. The first fitting on the left is a 3/4 x 1/2 x 3/4 T. I should have purcased a 1/2 x 1/2 x 1/2, but I didn't see any at HD or Lowes in my area. Anyways, I used one 3/4 to 1/2 bushing, so no biggie. That's a thermometer on the left side as well as 3/8" plastic tubing that I'm going to use as a sight tube. Lastly, I welded in a heater element bushing I bought from Bay Area biodiesel. It worked well. I am going to seal both with high temp sealant and water test tomorrow if I have time.



That's one thing I need to do right away: water test. I have not done so, but that was on my list to do before I work on the condenser.

This message has been edited. Last edited by: Bob_98SR5,

Will bio ever come into contact with those deck fittings Bob? If so, will the bio melt the plastic?

Also, welds on cast iron fittings like the bushing and tee are porous and will leak. I got round this by cutting up fittings made from threaded steel pipe, not cast iron, and welding them on where needed.

Paulus,

The plastic deckplates will not come in contact w/ BD, only WVO. This barrel is the 2nd barrel in the process. It's purpose is to accept cold upflow'd WVO that I will heat to 130F, and settle for dewatering.

Re porous welded fittings, yes, I've experienced that and try my best to weld a continuous seam, or as small # of seams as possible. I coat the seams w/ a generous layer of high temp sealant too just in case.

Makin' some progress...

Today I filled the processor up with about 1/4" of water. I'm happy to report that it passed the water test (yay).

The dewatering barrel has 2 tiny pin holes that need to be sealed.

After reading more about eductors, I decided to make one and modify my system a little bit too:



As you can see, the main difference is that I plumbed the primary venturi line into the true bottom (now top) heater element port. just below it, I am going to use the 2 extra ports for a sight plug as well as a eductor pipe for better mixing. this line will mix from top down. the nozzle's tip should be at the top of the wvo as i read in a thread this morning.

I may need to do some more welding to get the series of pipes to fit. the 3/8" bell housing does not fit through the 1" port that I welded onto the true bottom (now top). however, i probably could grind it down to make it slip through. much slower than welding though. we'll see what i have time for.

here's a pic of the eductor tip. i welded it, ground it down smoother and then used some jb weld to seal the 2 pinholes i found

It looks like you will have the hot setup!
Curious, why not use the venturi for the methoxide input? With my setup my pump would just cavitate when I tried using it for drawing in the methoxide. I now draw a slight vacuum on the reactor to suck it in...
Jon

Hi Jon,

In the early part of this thread, it was argued that i'd get better mixing if I put the output side of the methoxide at the input of the pump. That made sense to me, so I routed it as such. But when I started, I had it like you said with the methoxide being sucked up by the venturi.

We'll see. If i get the same cavitation, I'll just route it to the top. In preparation, I'll put a T up top where HV8 is

Bob

p.s. thanks for your latest round of notes. I'm still waiting for my PID

Jon, it's hard to see why your methanol/lye solution would/should cavitate at the pump's inlet. For pumps like these to work properly, the liquid being pumped has to nearly "fall in" to the inlet with as little restriction as possible. That's why the inlet is bigger than the outlet. The pump doesn't suck, it pushes.

I guess in other words what this means is that pressure should always be positive at the pump inlet, and not negative.

Bob, James RL who makes the venturis would tell you that all bends downstream of the venturi should be flowed. Your four-way cross isn't flowed, the oil will take a real sharp 90 degree turn, plus there will be turbulence. It will affect the venturi performance.

paulus,

so then i'll have to buy or fab up something like this?



if yes, then it then possible to have both an eductor and a venturi? is that what james fab'd up?

i dont think this will be too difficult, but just time consuming. just have to cut up a T and then shape the cut portion to make a Y and then weld it. if the angle isn't right, then I would consider cutting up a 45 degree fitting onto the T. i wonder though, if there would be cavitation at the right-most Y to effect the performance of the venturi when I am loading the processor with oil?

if this all doesn't work, I can try to run the eductor from the bottom of the tank too, but i'd have to weld in another 1" fitting to do that. no biggie, i'm up to trying everything at this point. i'd rather put extra fittings in "just in case" than disassemble everything, lay it down, etc. to work on it again.

on a related note, here's a pic of the eductor tip that I just finished:

Be prepared to spend a lot of time on this hobby.

Here's an inline heater I welded up, specifically because of James RL's comments about needing to flow everything. Prior to this the pump output (150L/min) was going through an elbow before hitting the element.

http://i121.photobucket.com/al...lineelementsmall.jpg

Eductor - I was under the impression that an eductor is more complex than in your pic - not just a jet (from what I can see.) Search for eductor and and jamesrl, he made some beauties, he is a retired coppersmith by trade.

I found it was more straightforward when making up pipework not to use cast fittings but to tig up what I needed from black pipe. Luckily I was given a heap of ex-fire sprinkler system 1-inch pipe and if I need a thread here or there just cut a thread from a pipe end and weld it in, the same with bends.

Don't know if the y take-off will be turbulent but would have to be better than a sharp bend.

Paulus,

Time, i have shoot, look at the time i took to get my darn mercedes roadworthy!

i'm going to experiment with fab'g the black pipe first and see what it does. if it works poorly, then i'll try the steel tubing w/ bent pipe work. my buddy has some 1" DOM tubing that I'm sure he won't miss b/c he has a lot of scrap.

oh, to measure venturi vacuum (hg/in)), where's the best place to put it in my schematic?

based on your feedback re cavitation, I'm going to move the sight plug somewhere else.

about the eductor tip shape: i was reading one of rick's threads he started and thats where i got the idea of doing this. might as well incorporate and test vs tearing it apart and adding it in. i will weld it so that the pipe is welded to a bushing. if it really sucks (and i mean in a bad way), then i'll just remove it and maybe buy a real eductor later. but i am guessing mixing will be better with this than without (pure speculation based on NOOO real world experience)!

i have some questions about your picture you posted. is it ok to ask you off line via PM?

Thanks,
Bob

Hi Bob

To measure vacuum do you mean where to place a vacuum gauge? Anywhere on the venturi suction inlet pipe. Only two things could influence pressure along that pipe - elevation (negligible) and pipe friction. Your choice where to put it.

I'm not sure what a sight plug is, Bob. You mean something to look into to see fluids moving? Given that it will all be a blur, why would you want to see that?

The educator that James RL makes has (from memory) a circular pipe bit around the outside perhaps to create a "wing" low pressure effect and suck surrounding fluid into the flow. He very freely gave me the information to let me make my own venturi.

PM away!

There are two basic components to the common mixing eductor. The nozzle and the diffuser. The diffuser is the bell shaped section that the nozzle sprays into. The diffuser improves the mixing efficiency of the nozzle, but it is not required. We only need a little bit of in the tank mixing to serve our needs. A nozzle alone can accomplish that.

The problem with adding a diffuser is the diameter of the eductor gets dramatically larger. Leaving off the diffuser lets you stuff it through a much smaller hole in the tank.

JamesRL did make some test eductors for me with diffusers that would fit through the inside of a 3/4" coupling. They worked great.

Thanks Rick.

The project is not dead! I was waiting for my PID parts and got into a little dispute over what I received in the mail. In that time, I ordered some more little parts and put a welding cart together. I started with a bed frame:



And fab'd this up over two weeks. Here's the cart with nothing on it:



And a front shot:



I need to gusset up the front outriggers, add some cable hooks, some flooring, and a welding table on top. I am also considering adding some arms that surround the tank that will act as a push cart and to also secure the tank too. But for now, it does the job. Oh, I may paint it as well, but damn, I'm so done with this!

Tomorrow, I'm going to weld on the 3/8" nozzle and then test it for water leaks. Then I'm going to test spray to see how well it works. I also plan to wrap up the pre-heating/de-watering tank with bubble wrap and firm up both the water tank and the dewatering tank with more wood.

Nice cart!
Good idea on the bed frame... Now I have something else to be on the lookout for...
It seems new steel is more expensive than I had anticipated, I figure the retailers around here likely still have older stock from before the prices started dropping.
Jon

Jon,

I bought this frame for $10 after seeing it on Craigslist.org. I've since learned that bed frames are often times thrown out when apt. leases are up. So check at the end of the month and see what turns up. And don't even try to cut the frame w/ anything except a chop saw or grinder w/ cutting disc.

I finished wrapping up the 30gal dewatering barrel. I added a ground screw by welding it to the outlet pipe's & fitting. Man, the wrapping part took longer than I expected to get it right.



We'll see how it works

Next up is to wash it out as there are bits of cut metal and definitely some fine metal dust in there.

In my effort to do just a little every day, yesterday I moved some stuff out of the way so that I could wheel the processor cart over closer to the front yard hose. I have some really crappy nazi old lady neighbor who gives me s##t all the time about anything I do, so I have to keep things out of her view no matter how innocuous.

so this evening, I pulled the hose into the garage so that I could mark up the site tube on the dewatering barrel as well as clean out the processor. both went really well as the water came out really clean on both. there's still some remnant suds in the dewatering barrel, but I'll probably do another water washing on both. but the most important aspect of filling the processor was to determine the number of gallons at the point where the water heater element is. thats the place where I will be running the venturi pipe through. it turned out to be around 32 to 33 gallons. therefore as many have said, my batches will run around 25 gallons if I use 20% methoxide (5 gal).



I also got my eductor parts from McMaster ready for welding tomorrow. I bought two merchant couplings so that I can run them through a 1" pipe fitting i welded on the top of my processorn. not even a 1/2" to 3/8" pipe reducer would fit through the 1" fitting. Since the sides are smooth on the merchant couplings, they go right through with no problems:




Finally, I found a Y-fitting from McMasters as well. Officially they are spelled "Wye". This is to address the concern that the sharp bends I was going to have for the eductor and the venturi might cause issues. I am also going to weld on a 45 degree fitting to it so that the flow will presumably be better than if I put on a close nipple and then a 45 degree fitting:



For tomorrow, I'll need to test the eductor performance. That should be fun!

Looks like its all starting to come together Bob!
You will be brewing in no time.
Jon

I didn't allocate a whole lotta time to the processor this weekend, but I did manage to get some crucial pieces out of the way. First, the eductor: long story short, I welded everything that needed to be welded in place, but had to shorten the pipe b/c of a brain fart measurement. I incorporated that low profile connector just in case something like this happened.



...and if this eductor looks eerily like that North Korean missile those nutjobs launched, haha, thats what I thought it looked like too!

Good thing for me is that I purchased a pipe cutter and threader from HF b/c I don't plan to take it up the arse anymore buying little pipes here and there to make things fit.



Anyways, I got the eductor the right length and tried it out w/ the water pump. Sorry, no pics besides this one which shows the hoses connected and ready to be utilized for the water testing:



The stream out of the eductor can best be described as a 3/8" fat stream. It reached the top of my neighbor's avocado tree. I should've soaked him Not sure how this will work inside the tank, but I'm sure that's a good sign that it can shoot that far.

Now I do also have an eductor Plan B: I purchased a specialty part from McMaster which is designed to shoot a jet of water with no fan pattern. I'll post up the part number if its successful. The tech diagram and description (IIRC) said that this metal pattern inside the tip creates the jet stream. This is the inlet side:



So b/c I didn't have a 3/8" tap, I bored out a 3/8" pipe w/ a HF hole boring drill bit (I love these things) and finished it off with a 1/2" bit. It was a slightly snug fit which is what I wanted.



I cemented it in w/ JB Weld and I'm watching it dry as we speak I'm sure it'll hold well. I ran out of daylight before I could test this. It'll be Wed by the time I weld the other end of the 3/8" pipe to a 1/2" pipe.

I also welded a 13 inch 1/2" pipe to a 3/4" bushing. This will serve as the pipe on the outlet side of the venturi. I also welded on a a 45 deg bushing to the McMaster Wye fitting I purchased a few days ago. I am definitely getting better at the welding, but its still hard to get a leak free weld. JB Weld is turning out to be my best friend. Here's a pic of everything dry fitted:



I'll be connecting pipes soon. Stay tuned