I am working on a design for an "Appleseed" style reactor. Many of the reactors I see that people have built have an external "sight tube" to see how much WVO is being put into the reactor for obvious reasons. :-)

My question is: How do you clear the WVO OUT of the sight tube so it reacts with the rest of the batch?

I see most processors have valves above and below the sight tube (or in other arrangements). Does opening the bottom valve "suck" the oil out for processing?

I assume you open the valves during filling .. so you can see the current level.

Thanks in advance!

There are a couple of ways to deal with the oil in the site tube.

1) if you have a valve between the site tube and the tank sometimes called a tank isolation valve because it isolates the tank from the lower plumbing. close that valve with the valve at the bottom of the site tube open and run the pump.

2) if you don't have the valve above, you can run the pump and if your oil is thin, the pump will pull it down into the lower plumbing.

3) don't worry about it. once the oil is loaded, close the valve at the bottom of the site tube and leave it closed until your ready to load your next batch.

Another way is to us a clear hose that's only connected to the bottom of the processor, the other end being open. Hold it up and open the valve to see the liquid level. Close the valve and you can drain the liquid from the hose. This will eliminate the concern that a permanently connected plastic hose might rupture, however there are some caveats worth mentioning:
1) The processor must have a vent open to the air BEFORE opening the hose valve.
2) The pump must be off.
3) The hose must be long enough to show the maximum liquid level.
4) Remember to close the valve when not in use.
5) The hose will dribble forever, and has a mind of its own.

OTOH, the hose is handy for draining glycerin, or suctioning methoxide, or draining the last little bit from the processor if mounted to the absolute lowest point. Since it's only used briefly, the plastic can be less durable (cheaper).

Thanks for the replies! :-)

The plumbing I am initially looking at would have a valve at the bottom and connect to the top of the processor with an open (without a valve) pipe.

So when I start the pump - from what I understand, it should pull the oil from the tube as well (using siphoning). If I shut the bottom valve.. it won't - but I plan on metering the WVO using the oil in the sight tube to get my measurements correct. So I will definitely want to draw the oil into the processor when I begin circulating the pump.

Once the oil comes down.. I could go ahead and close the valve I guess. Will have to see how it works when I fill it with water for measuring and leak-testing I guess. :-)

Thanks!

Another way is to use a sight tube that can handle the temperatures, pressures, and chemicals used in processing then plumb it right after the pump.

I use a static mixer I sell on my site for mixing and for a sight tube.

http://www.fryerpower.com/store/page12.html

-Jim

http://biodiesel.infopop.cc/eve/forums/a/tpc/f/41960555...911089422#7911089422

If you are using one of the TAH Static Mixers that I sell DON'T RUN H2SO4 THROUGH IT!

Also, even though they are rated for 250F I would not run them above 170F just to be safe.

-Jim