This is good advice. It is 10x harder to pull vac on these systems when they’re perfectly clean and cold.
4 Likes
Check valve or ball valve or cap?
IMO, check valves are unreliable to block vacuum
Caps or rubber plugs get messy and nasty
Ball valves reliably block vacuum but dumb operators forget to open them and cause different problems
If it was just me running it, I’d put descent (Swagelok/Tylok) ball valves on the outputs and not open them until there was enough oil to cover the pump inlet
5 Likes
@greenbuggy thats solid advice.
It’s been such a crazy week that I forgot to come back and thank everyone for the help and update with pics! So I cleaned up one of the gear pumps with a polishing wheel on a bench grinder, then hand finished with a dremel. It came out pretty nice! The shaft would not slide through the plate when I started, but it slide in and turned fairly smooth when I was done. Got it back together and was finally able to distill several units of material.
One thing I didn’t realize about running these things is how sore I’d be! I woke up yesterday and every muscle in my body hurt. I haven’t been lifting or tugging, just squatting to peer into the sight glasses and constantly pacing back n forth to see whether the vac goes down or not. I think I put somewhere around 50hrs in this week 
7 Likes
Were there scratches in the shaft or bore that were in parallel direction with the shaft?
I’ve seen these get scraped up when people have to hammer them out, unfortunately the OEM made them stainless-on-stainless rather than having a wear surface from a different material that isn’t so likely to cause galling (as stainless unfortunately loves to do, especially when hot)
I’ve had some luck putting the plates in a 4-jaw chuck on a lathe and using a piece of fine scotchbrite wrapped around a looped TIG rod to polish the inside bore. Shaft OD you can clean up with fine sandpaper or a scotchbrite pad and either a lathe or drill. Just gotta be careful to not take out too much or you can create a massive vacuum leak on the side that doesn’t have the shaft packing
4 Likes
Rest up bro.
3 Likes
So yeah it was galled to shit. I’ve had many many hours experience polishing parts when working on motorcycles, so I decided the gentlest, albeit most time consuming, approach would be to polish it down instead of working it up with all the grits of sandpaper that I don’t have. Unfortunately there was still some scoring that I would’ve actually had to change the dimension of the shaft to take out, so I left it, but everything was as close to mirror finish as I could obtain with my patience. I could still hear squeaking when it was running, and it definitely made me cringe to hear, but I was able to pull down to 30 micron with the diff pump running so my vac leaks are very minor at this point. I will end up swapping the distillate and residue discharge pumps so that the pump that I worked on doesn’t end up fucking us mid run. I’ll probably end up tearing it down again and see what’s up. I kept getting very small particulate in the distillate so I gotta figure that out. Also ordered some kf screen gaskets to prevent it in the future.
2 Likes
We used a conical reducer over the outlet with a section of screen stretched across it and held in place with an o-ring/clamp. Worked like a charm for getting that small stuff out and could usually get through a whole run without changing it depending on the starting material
2 Likes
Right on. I probably way overspent on my screened centering rings at 25$/pop, but they looked slick as hell and I just had to have em. I worked till midnight Friday night putting together orders to upgrade the system after having ran it several times. I’ll make a post about all of the changes I’ll be making as they are gonna be cool and useful. I even have a way to add a feed funnel in the event we want to run sub kg amounts through it as we were finding that if we didn’t have enough material in the feed flask, it would get stuck in the feed line and let air bubble through killing the vac and distillation.
3 Likes