It’s what I use as well. They wear out over time and I just dislike o-rings in general.
It was more of a joke then anything.
Don’t have any issues pulling super low
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This is one reason we have been moving away from peri pumps.
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It’s been a rough fucking day…
Gotta find a glass blower to fix my cow because I can’t find one that keeps my shit in line.
what state?
Michigan
Is the intention of the pump just to suck the residue out of the bottom of your BF at the end of a distillation?
Obviously WFE is fed continuously, I’m just confused if you guys are talking about continuously feeding crude into an SPD (or just initial loading?). If you’re talking about a continuous feed, I have no idea how that would work practically but that’d be really cool.
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No, but thought about that as well 
Thinking more of replacing the recieving flasks.
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Oh well that’s less exciting… but I could still see that being useful!
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Agreed!
When do they collapse?
Usually from the vac to pressure side. And it’s a tightening of material in the lobal area like a band.
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Ive been thinking of a work around.
Here me out.
Cheap mans spd discharge pump.
Wrap your peristaltic pump line with a heat line, so disty always stays hot enough to flow. Connect the outflow line of the P. Pump to a media bottle with a two way adapter top that is pulled to full vac. Since theres no pressure differential, the pump should pump out just fine. Im going to order all the parts and figure out the best way to get a good seal on the P. Pump line connections. I know the hoses will leak alittle, but maybe worth a try. Its not the best solution but its cheaper than 6k and ur disty is in a media bottle when ur done instead of a flask
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A good check valve in there would probably make this work awesome
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The issue is when disti or solvent comes through a peri hose the hose turns to a rubber band due to back end vacuum., This creates tension on the gear roller and burns out motors generally. They make some robust models but they leak and aren’t as durrable as a gear setup.
Any recomended gear pumps ? I need 2 for the spd flow rate off 5L an hour should be enough
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try witte for the gear pumps
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Might be a bit late and not sure if this’ll work, but you could just buy a small gear pump on the internet that is the right material and configuration, SS 304 with a top in bottom out config, then just adapt the ports, likely npt, to kf25 to 24/40, or however you deem fit. You have to take extra care to seal your npt fittings because they aren’t great for vac. This avoids the need for tubing altogether and keeps it cheap.
I’m looking just on google, but there’s some affordable gear pumps that do very small quantities, which is fine. You do have to make sure that it can actually hold vacuum, but there’s a handful I’ve seen that are ~$200-$400 that look good; check technical sheets though.
Chances are you’ll have to also buy a controller as well, but that shouldn’t be to complex.
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Yeah, a check valve will likely help, the main thing with both the pump and the check valve you have to check is the tolerance. They do have to be really sensitive because if your check valve allows even 0.01% back in, that can ruin a high vacuum because that’s .76 torr. Similarly, if the pump isn’t fast or tight enough, it can set a hard limit on your ultimate vacuum.
Can you list some models you’re seeing cus I’ve been looking for a while and only see a few fit for the job and there spendy oob. Thanks @Neutral
Sure, I’ll note some that I saw could work. I haven’t looked at any technical specs yet; you will have to do the calculations yourself, but ideally we are looking for high pressure pumps (a few hundred psi) with a tight tolerance where we can approximate backflow. If we have a high pressure gradient (ex. 200 psi) and it only lets back a 0.5 psi back, that’s a good pump; so a high tolerance and high speed pump is what we are going for. From here, you estimate the volume of your still, the pressure and volume of air that will backflow to estimate our ultimate pressure. If the ultimate pressure is lower than what you are working with, there you go, a cheap discharge pump.
In terms of what we actually need for this job, the one that summit offers doesn’t look that expensive, though if it has tight tolerances, that’s where the money is. However, Summit does have very high prices for even relatively simple glassware (not a criticism, I actually agree with a high price business model, as long as you deliver a good product and have good service, which they do.)
Here are some pumps that I found with some very quick searching, listed from cheapest to most expensive, though they may not all fit the specifications I listed, and they do get expensive quick.
Very cheap, still requires tubing, probably shit.
https://www.coleparmer.com/i/miniature-gear-pump-0-67-gpm-2520-ml-min-12-vdc-lab-model/0701220?PubID=UX&persist=true&ip=no&gclid=CjwKCAiA7dKMBhBCEiwAO_crFHYN13854R0xfSJd7WltL91eyGL6TSF4nTTVoYRTBAQ3tAchr0KgMxoCPNAQAvD_BwE
Getting there,
Pump head only
Really, you should build it yourself, spend the money on a good pump head, and buy a separate motor/controller.
Note: all of this is broad strokes and estimation. I’m not an engineer so much of this is imprecise estimation, but pressure isn’t the hardest math I’ve done in my life.