Centrifuge!

This Friday EWH went to Tengeru hospital. And I got to work on a really messed up centrifuge!

This is what it looked like when we first got it… Everything is in pieces, parts are missing, and it is full of dirt and mice poop. 🙂 Brendyn and I took the control panel and motor out and got to work.

Looking at the pieces we know we are going to have to rewire everything. We started by reading the motor specifics and found out we could run it straight from 220 V. It would spin really, really fast. On the left of the control panel the big round thing is a potentiometer or variable resistor, we want to connect that in series with the electrical power going into the motor so that we could control the gradations of speed that the centrifuge spins at. Finally, we connected a power switch in series with all of that and connected everything to the power cable. And it worked great! Here are some of the pictures of the process.

We started by cleaning it… this is the bucket of water before and after. I don’t know where they were storing this thing but animals had definitely been living inside.

We then assembled everything once our circuit was ready to test.

Once we knew it was working we soldered all of our new connections and heat-shrinked them.

And bolted everything down and screwed it all together.

And we have a working centrifuge!

Here is a video of the finished centrifuge running:

However, since the control panel was missing pieces the last missing component was a measure of RPM that the centrifuge is running. A doctor or lab tech could control the speed at this point but not determine the rpm exactly (which can be important).

To fix this we used some cool physics. With a strobe light flashing at a specific Hz frequencies and looking at when the tubes “appeared” to no longer be moving (they were spinning so fast under the flashing light we couldn’t discern any movement) we were able to determine different important RPMs and mark them down on the dial at the bottom. We now have a fully functioning centrifuge with all the original controls!

Later:

We started working on some broken autoclaves (sterilization machines)

I worked on this machine. It had not plug so we put together a new one from parts and started testing it with water.

Here we are testing leakage current to the outside which was really bad for one of the autoclaves but this one isn’t too bade at 5V. We have to lift it off the ground so it isn’t “grounded” and the potential can be measured accurately.

And this autoclave ended up working! All we have to do is find parts for next week to fix a small leak near the plug that showed up under high pressure and it will be back in service.