Vacuum pumps and traps

So my buchner arrived broken and while I wait for the replacement I got my water aspirator hooked up with the hydro pumps I had. It doesn't seem like the pumps are strong enough and I can't feel any pull out of the vacuum hose hooked up to the aspirator. I think I'm going to invest in a vacuum pump vs getting a bilge pump to try and make the aspirator work.

I was looking at a few different pumps, from the CPS VP6D 6 cfm pump to a Chinese diaphragm pump (I can't post links yet):

Laboratory Diaphragm Vacuum Pump, GM-0.33A, Lab Vacuum Pump: If you put this into ebay it will bring it up: 262815662617

He lists it as .08MPA or 200mbar max vacuum.

My budget is not great but I would wait to get the 250$ pump if it was worth it. If a 140$ pump will work then I would rather go with that. The Robinair 15500 and similar look decent. I don't really understand the measurements or units on the Chinese pump that well, the mega pascals seems to be better than the CPS pump.

Also looking at best value vacs competing pump:
the ve160 7cfm for 215$

I'm going to be vacuuming a 1L buchner along with 1L vigreux distillation setup (not at the same time). I have a spot where I could easily have the vacuum pump in the next room (a working garage) so I don't have to worry about oil in the lab room.

After I figure out the pump I guess I need some type of valve setup? And a cold trap? I saw glass traps that were purchasable but it basically looks like a water pipe, I was wondering if anybody had a good lead on how to DIY a good cold trap. What types of valves and materials are good to use (tubing and such) if I plan to use ethanol and isopropanol in the system?

It kinda sounds like you are getting a bit ahead of yourself. First of all unless you live in Cali or somewhere there's a water shortage. A simple $10 water aspirator is all you need. I used one for years attached to a sink. That is all you need! You can run to waste. It will create plenty of vacuum. Is that the problem? You're set on making it recirculate? You wouldn't need a 6 cfm pump either. 3 cfm is plenty!

Welch diaphram pump is all that's needed for Buchner filtration. I use it on my rotovap as well. I bought 2 used on ebay for 180 each

Kid Kannabi5 said:

It kinda sounds like you are getting a bit ahead of yourself. First of all unless you live in Cali or somewhere there's a water shortage. A simple $10 water aspirator is all you need. I used one for years attached to a sink. That is all you need! You can run to waste. It will create plenty of vacuum. Is that the problem? You're set on making it recirculate? You wouldn't need a 6 cfm pump either. 3 cfm is plenty!

Click to expand...

I have a well and can't just run it continuously although it probably has plenty of pressure. When I need to filter and distill off it will probably need to run for many hours and it would be too much water to just run to waste. I don't want to buy a bilge pump to find that the aspirator doesn't meet my needs and then have to buy a vacuum pump. I'd rather get a vacuum pump that will do the trick.

@DemonTrich I did check ebay and I found they have these Welch Ilmvac 2585B-01 Dry Vacuum Diaphragm Pump Oil-Free for 350$ but they test them all via calibrated gauges and the list price for one of those is 1400$...

Keep checking daily. I'll keep.an eye out as well.
.SCREW the aspirator. Too many variables with it. Must keep cold or vac poops out and chilling stops.

Home made chiller perfect for rotovap.
2 versions

1st way
Run garden hose from.house faucet thru condenser
Cold water all time. Water is low enough as to not waste too much. Or empty hose in bucket and use for mj waterings

2nd way
5g bucket
390gph aquarium pump (a stronger pump may be needed depending on length of water lines and size of RV)
PVC fitting
Hoses

Fill bucket with cold water half way. Fit PVC into pump, drop pump in bucket. Secure water lines to proper spots on condenser. Run OUT line back INTO bucket. Recycles all the water. Add ice to bucket.

Here ya go
199

https://www.ebay.com/itm/Welch-WOB-L-Pump-2522B-01-Laboratory-Vacuum-Pump-Pressure-WORKING/301310996537?hash=item462788f039:g:~FoAAOSwmUdUYZOG
I own 2 of these above

https://m.ebay.com/sch/i.html?_from=R40&_trksid=p2055413.m4084.l1313.TR2.TRC1.A0.H0.Xwelch+wo.TRS0&_nkw=welch+wob-l

So 100 tor should be good enough for distillation? That seems like a killer deal on that vacuum pump with gauges and everything.

[edit] I need the vacuum to be good enough to run the distillation setup I mentioned in the OP, basically 1 liter chamber through a vigreux column into a 1 liter catch, using ethanol.

Based on skunkpharm's pump evaluation I would want something stronger than those welch models will go. I think I'm probably stuck with getting a rotary vane oil style pump and trying to figure out what to go with...

So I was perusing ebay when one of these: Pro-Set CPS 6CFM Two Stage Ignition Proof Vacuum Pump 1/2 HP 10 Microns came up for like 150$ shipped new (packaging was damaged but pump looks brand new). It's a fancier version of the CPS VP6S and that was like 1/3 of what it goes for on best value vacs. I figure its a paypal ebay transaction so I will test it when it arrives. I also got one of those jb m2-250. I'm going to shop local hardware stores for the fittings and such to put it all together. I figure a ball valve to a tee to the vacuum gauge, and then ball valve into a 1/4" npt barb for vacuum hookup (distillation system hookup) should do it. vacuum pump -> ball valve -> tee -> ( 1/8" npt female -> Gauge ) / (ball valve -> 1/4" npt barb)

I run a Welch 1400 duo seal for my SPD. Welch wob-l diaphram pumps for buchner filtering, and also my 5l rotovap. I use a robinair 2 stage 5cfm.for my 1.9cu' vac oven

DemonTrich said:

I run a Welch 1400 duo seal for my SPD. Welch wob-l diaphram pumps for buchner filtering, and also my 5l rotovap. I use a robinair 2 stage 5cfm.for my 1.9cu' vac oven

Click to expand...

That was a really good deal on the welch but I probably only have budget for one vacuum pump for a while and I think the CPS will hit all of the points with a little work. I'm a little nervous about getting it all hooked up but I figure I'll take my time and learn the setup by doing a few runs w/o material to get the feel for it. My buchner is supposed to come today but now I get to wait for the vacuum pump

I hope to take some pictures of the process to share here when I get up and running.

So the pump came and I got it all oiled up and hooked up to the manifold I built. It hit full vac in about a second. I turned the pump off and it kept steady 30 on the gauge, and I could slowly control it with the ball valve. This thing seems like quite a beast. I'm glad I have a fresh air intake in the manifold to lessen the vacuum a little bit. My stand comes tomorrow or I think I would start running solvent through tonight. I don't trust rigging up the condenser without a stand

mainesquirrel said:

So the pump came and I got it all oiled up and hooked up to the manifold I built. It hit full vac in about a second. I turned the pump off and it kept steady 30 on the gauge, and I could slowly control it with the ball valve. This thing seems like quite a beast. I'm glad I have a fresh air intake in the manifold to lessen the vacuum a little bit. My stand comes tomorrow or I think I would start running solvent through tonight. I don't trust rigging up the condenser without a stand

Click to expand...

Best to wait for stand and clamps. Make sure that precious glassware is secure. 3 cfm pump? You will be wanting an oilless pump eventually. That oil exhaust is bs. I plumbed my tubing outside and ran it outside when I used a similar system

I plan on using a tube to vent the exhaust. The pump is a 6 cfm and it supposedly has some sort of filter on the cap to help cut down on oil exhaust. I could easily run it in the next room if need be.

The stands and clamps came but I'm still waiting on the cold trap (to protect the vacuum from ethanol fumes and protect the system from any possible vacuum pump smell/etc). I thought about getting 2 3/8" bulkhead fittings and using a canning jar to make my own cold trap... The safety of canning jars under vacuum seems to be on the fence (some say they work fine and some say they will implode). Do you guys all use cold traps and what would you think about making a cold trap out of a canning jar?

To catch the terps? Yes, short path distillation apparatus w/250 ml rb flasks. I know a canning jar will indeed handle a full vac -29.8 in. Hg. Wouldn't be my first choice, but it would handle the neg. pressure.

I just scored a welch 1402 For cheap. If your local, this bish is 80#+. Can have for 300.

If I had 300 I would be all over that, a bunch of you guys are from Maine, yeah?


So I hooked it all up and put some alcohol in to distill. I had kept my alcohol frozen and then trying to get the temp to come up under vacuum was very hard. I had setup and tested a double heat mat which seemed to work fine before but it took forever to get the alcohol above freezing and even then I couldn't get it above like 60 deg F. Even still the alcohol slowly dissolved off. I kept track of the rate by seconds in between drops. I started off around 8 secs in between drops and then got to 3 sec between drops. It was taking forever but I closed it off and took stuff down. I tested the alcohol I distilled vs the alcohol from the bottle (Everclear 75.5% or 151proof) and the stuff I distilled was significantly stronger.



I hooked things up with a hotplate double boiler setup for heating the distilling flask. I had to make little shelves to get things to line up properly and its a pain in the ass to swap out flasks but it works. I initially hooked up the cold trap backwards dropped vac and flipped it around. I was able to get the distilling flask to boil. I didn't like how the vigreux column was warmer and it was harder to keep the cold side cold. I got it to a constant drip and ran it for a few hours and then chilled it and passed out. I'll post a few pics later after I charge my phone up.

I did find a deal on a glas-col heating mantle with the cord for 60$ shipped, so when that arrives later in the week (hopefully) I will have an easier time with the heat. I plan on hooking it up to a dimmer. I almost have a full liter of full test ethanol! My material is getting all ready to go. I find waiting for reactions is a good time to break stuff up and pack it into jars.

I'm in the semiconductor field, high vacuum is used for fab the IC's.

Anyhow when Washington became legal, what the dispensary's orderd to set up their shop's was

Dry Ice Foreline Traps
Direct drive mechanical pumps
Stainless Steel Isolation valves
Oil mist eliminators

You can find all this stuff at surplus actions / ebay