I don’t have any experience with a peristaltic on an SPD, but tried a few experiments with a peristaltic on the solvent flask of a rotovap under vacuum. What I found was that a 3 roller peristaltic allowed a lot of backwards flow/reversion to happen, moving liquid back towards the vacuum source, which slowed output considerably from what I saw from that same pump when it was pumping liquid from even pressure zones. I suspect to get descent flow characteristics you would need at least a 6 or 8+ roller pump in either application
With thicker tubing you lose some amount of flow, but it’s not like an SPD output pump needs to move a ton of liquid volume in a short timespan. For what I was trying to do to empty a team of 6x 50L rotos, a 6+ roller peristaltic that used 1" or 1.5" tubing was cost prohibitive, but smaller units with a higher roller count should be more affordable, downside is that you may run into a problem where the motor/gearbox affixed to it isn’t sufficient to pump against vacuum at 100% duty cycle, and using a VFD to slow down a motor’s speed also typically slows its cooling fan which means more heat which isn’t good for the drive motor’s longevity.
I think Elliot is completely wrong claiming that the low speed that peristaltic pumps operate at is the reason that they can’t maintain operation under vacuum, it’s all about tolerance and whether the pump is completely closing the hose opening or not. If you have to crank the RPMs way up to maintain vac levels I can only think you’re using the wrong tool for the job.
I was using 3/8" silicone brewery tubing in my pump and didn’t have problems with it collapsing under vac. I would expect that the larger diameter you go, the less selection and more $$$ you’re going to have to pay to get a thicker walled tubing that’s suitable for what you want to do.
I’m afraid I don’t have any recommendations for brands to try this out, what you want is something that’s really overbuilt for your application, both from a motor HP and gear reduction standpoint as well as a rigidity/frame/industrial usage standpoint.
I do agree that $7k for a relatively tiny gear pump with a high NPSHR value seems insane.