Sight tube valves

[pangit Moderator Find all posts View Profile Close pangit]

I'm currently designing/building my appleseed processor. The water tank I've got has two sets of top and bottom holes on opposite sides. I'm going to put the pump and all the drain/fill plumbing on one side in the usual way.

I am thinking of putting a sight tube on the opposite side, simply connected between the top and bottom holes with no ball valves, and not connected to anything else. This means I can't isolate it or drain it separately from the main tank.

Does this matter? Can't I just leave it full until after the reaction when I will drain the glycerine and pump the biodiesel out to the wash tank? I am intending to use KOH so am not expecting any solidification.

[pangit Moderator Find all posts View Profile Close pangit]

Re: Sight tube valves

Another thought - do I even need a separate sight tube? When the pump is off (it's a standard 1/2HP centrifugal water pump mounted vertically) won't the filler tube act as a sight tube?

[hdj80 Senior Member Find all posts View Profile Close hdj80]

Re: Sight tube valves

My sight tube is multipurpose.... It acts as a primer for my pump as well as being a sight tube. It has a valve at the base and open to the atmosphere, once the processor is filled the tube is drained. I have not, but you could refill the tube straight after stopping the processor. But I prefer to drain all the plumbing into a plastic drink bottle with a popper top (approx 300mls) turn it upside down (top down) and watch the process happen in the bottle. BTW that bottle has only been sitting there for a very short time as within 20 mins the glycerol is 2" up the neck....