eVOLVER Forum

How do I stop my peristaltic pumps from pulling on the silicon tubing?

My lab has had an evolver for about a year but we haven’t been using the turbidostat mode regularly. I’m trying to get the turbidostat mode back up and running but a few of the pumps will pull on the inner silicon tubing and push it through causing the connection between the silicon tubing and the longer media line to break, spilling media everywhere. When this happens I have to open up the pump housing and readjust the silicon tubing but even after I do this it still seems to pull and will eventually have the same problem. I’m afraid to run very long experiments right now because I expect the tubing will eventually split and spill media/culture everywhere when I’m not around to fix it.

Has anyone else had this problem and are there any suggestions for how to fix it? I checked the adafruit forums but there doesn’t seem to be anyone with my same problem there (this pump is adafruit product 1150). Adafruit seems to claim that these peristaltic pumps don’t need lubricant. My two first thoughts for how to fix this would be (1) apply some lubricant (2) replace the silicon tubing (maybe it’s too old from sitting for a year?). Or maybe someone else has experience with this? Is it possible I’m putting the pump together incorrectly and priming it for this behavior?

Welcome to the forum! Some pictures would be great so we can give you better advice.

Cheers,
Brandon

I took pictures before and after running the pumps for 30 seconds. Here is an example of one pump that is slowly pulling the silicon tubing through the rollers until the silicon tubing snaps off of the connector.

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after picture

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There are two notches on the slides of the pump head that let you remove it. After removal, you can take the whole pump head apart from two more latches. Try taking it apart and putting it back together. I typically haven’t had any issues with the silicone tubing pulling off (from testing ~1000 pumps) so maybe this is just a bad one.

If all else fails, you can order the pump from Adafruit and just replace the pump head. Hope that helps!

I’ve had to take many of the pumps apart and put them back together and they continue this behavior. Since no one else has seen this I’m going to assume that it’s due to the silicon tubing getting old or something and I’ll try replacing all of the tubing inside each pump. Maybe no one else has seen this because people don’t typically let their tubing sit for a year without using it much.

Edit: I hope this isn’t an issue with the pump that can’t be fixed without ordering a new pump because it’s happening with about half of my 32 pumps and continues to happen after I take the pump apart and readjust the tubing inside the housing. Maybe I need to clean the rollers too or something.

This is a problem with that batch of pump heads. We’ve got a few eVOLVERs in the lab that were originally built with the pump heads with blue rollers, and they all have had that problem eventually. While I replaced most of the pump heads, for one eVOLVER I ended up leaving some on with a piece of lab tape wrapped around the peristaltic pump tubing, thick enough to no longer fit through the opening.

For these pumps (see photo, yellow tape, blue rollers, clear tubing), when the tubing gets sucked in, the pump pushes on the tape, rather than the luer component. This is enough resistance that it’s been stable that way for at least 6 months now.

However, the more long term solution would be to switch out the pump head, as the ones with the white PharMed tubing work fine, as did the original ones with white rollers.

Sorry for the inconvenience, didn’t realize anyone else had some from that batch. During the Khalil lab distribution era, oftentimes materials were bought in small batches leading to device to device quirks due to differences in part suppliers.

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Before the tape I tried cleaning the rollers with water and paper towels, readjusting the tubing, and flipping the tubing in the opposite direction, but none of those were permanent solutions.

Ah thank you so much! The tape seems like a pretty decent solution. I’ll try that and if it doesn’t work we’ll go ahead and replace the pump heads.

Oh maybe zip ties would work well then! As long as you dont tie them too tight…

Maybe, worth a try, would certainly be cleaner/faster than all that tape. But it might be finicky to ensure it grips the tubing while not pinching closed. I think placing the force on the tubing rather than the luer component is the key, so a loose zip tie acting like a washer wouldn’t be sufficient.

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So I’ve been trying normal lab tape and it doesn’t quite seem to have the grip needed to keep the tube from slipping. I might be able to use a different kind of tape or zip ties.

Do you guys know if anyone sells just pump head replacements that would fit with these pumps. I believe they are adafruit pumps (ID:1150), but I wasn’t actually around when they were purchased and assembled. Do you know if the current adafruit pumps have this problem? Or do you guys purchase pumps from somewhere else now? Thanks!