Finished and functional project. Potential optional future enhancements.
Flow Cell.
Flow cells can be used in a variety of applications including continuous measurements of liquid media parameters like spectrometry etc.
Build information: I have not found any documented open source, working autoclavable transparent flow cell despite the fact I know that Alex (pipetteJockey.com) build at least one. He is such a talented individual.
The challenge is to find the appropriate autoclavable glass and connect it using only autoclavable materials like silicone.
We were lucky to find these quartz cuvettes on aliExpress for about 5$ each.
We needed to open the bottom by cutting if off or drilling it.
First challenge... cutting the glass
There were multiple attempts to drill the other end and all ended up with breaking the glass or making a hole and chipping the exit side of the glass. It's because of the pressure o the drill. It's actually easy to start the hole and drill but the end was always a disaster. It might be possible to drill from both ends but my diamond drills were not long enough to get from inside.
The solution was to use a diamond dust blade on a rotary tool(like Dremmel) knockout and slowly cut the end while completely submerge the cuvette under water. Takes five minutes and will splash you with water from the spinning blade. It leaves a pretty good edge but not perfect so you might want to file or grind it down a tad.
You can see the cuvettes and the rotary tool the cutting blade and the resulted cuvette. The blade was bought separately and it was several dollars from aliExpress for several blades.
The next problem is connecting them and that means capping the open end
I tried casting cheap bath renovation silicone in a 3D printed mold rued with soap and isopropyl alcohol so stop binding between silicone and mold. Pretty poor results yet encouraging. Initially I tried a cap that seals on the outside and inside but then I realized that any extra silicone on the outside might interfere with the ease of removing the flow cell from the electronics box containing the light and the sensor. So it's better to do something like a cork. I plan to order some cast-able silicone to try that but I remember I have a chunk of dried out silicone from a cocking tube somebody left for a very long time. You can see it as a white cylinder.
So I used my saw and my box cutter to hack a cork as you can see in the pictures. After that I used a stationary drill press with a 4 mm diamond drill bit to drill through the hacked cork. A normal drill bit could have probably worked as well. I cut one side of the bulk head connector as you can see in the picture then pushed the connector through the hole and then force this stopper in the glass tube by squishing and pressing on the corners until it's all in the tube. I screwed in the plastic PP nut and I snipped with a scalpel some more silicone for aesthetic reasons. It seems to be pretty strong but be gently inserting and removing tubing from the barbs to not uncork the tube. In case you want to be rough you might want to add put a short permanent silicone tube with another connector at the end so connecting or disconnecting tubes will not put any pressure on the silicone cap. Alternatively you can 3D print some bracket that does not have to be autoclave-able since it does not touch the media.
