Thoughts on vacuum pumps, oil contamination and more

[learningta]

I'm contemplating a few more things with regards to my terpenator build:

1) Is there any reason that a person couldn't use a 3-way valve with a filter on one of the ports for valve #1 on this diagram? http://skunkpharmresearch.files.wordpress.com/2012/09/terpenator-operating-diagram-1-13.jpg

It would seem to me that if you used a 3 way valve instead of a 2 way valve, when switching the valve over all vacuum to the pump would be returned to atmospheric pressure and there would be no way for the pump oil to bleed back into the recovery pot so long as the operator remembered to use the valve, right?

2) Alternatively, or perhaps in conjunction with #1, anything keeping a person from installing a trap made out of a sanitary spool between valve #1 and the vac pump? I'm thinking a spool of size large enough to contain all the vac oil in your pumps reservoir plus a margin of safety. I am thinking a long and short tube coming thru the top lid with the long on the vac side and short on the terpenator side. That way if an operator forgot to shut valve 1 any vac oil bleeds into the trap and never makes it back to the lower spool on the terpenator. Is this thinking correct, or would it still contaminate the lower spool just not as much as if oil came out of the vacuum pump and ran directly into the lower spool?

3) For people who already have a terpenator set up, is it difficult to open the lower spool to remove product if its under vacuum at the end of a cycle? Any benefit to an extra ball valve to bleed off that vacuum?

4) Is anyone running a lab style vac pump instead of the HVAC style pumps that seem to be recommended here and elsewhere? I'm wondering because I already have a Welch 1405 pump that I'd rather use instead of spending money on a new, crappier pump from Harbor Freight. According to the manual its a 3.2 CFM pump that can achieve .0001 Torr. Only problem appears to be that it currently has a tapered hose nipple on the vac port, but this removes to reveal a 1"-20 FPT port, so I just need to adapt that to a 1/4" male compression fitting to fit my HVAC hose set, right?

Thanks for the help!

 

[Gray Wolf]

1.0 I would work, but you would still have to remember to start the pump before valving it on, and valving it off before shutting the pump off.

2.0 I've done that between a pump and a vacuum chamber, and it works fine.

3.0 At -29", there about 381 pounds of force holding the lid on,

4.0 The Welsch 1405 should work. http://www.chemglass.com/pages/pdf/manuals/AF-0350_WelchVacuumPump.pdf appears to show a 7/16" hose adapter, but doesn't say what it is. I would adapt it to a 3/8" FJIC or Male flare and use a refrigeration hose.

 

[learningta]

3.0 At -29", there about 381 pounds of force holding the lid on,

How do you pop the bottom spool off after you release the clamp if its got that much pressure fighting against you?

 

[rb extractors]

you release that pressure first. we have a vent line that goes outside

 

[C'Ya]

What RB said and if it sticks and does often from clamp pressure I use a non-marring hammer and it a tap at edge clamp was covering.
I use a plastic dead blow hammer myself.

 

[Gray Wolf]

How do you pop the bottom spool off after you release the clamp if its got that much pressure fighting against you?

Take off the vacuum pump line and open the vacuum valve, so as to back fill the chamber with air.

As CY noted, sometimes they stick and you have to whack them with something non marring, or stick a thin jewelers screwdriver in the slot and pop it loose that way.