Well, the family is sick. Colds and general not feeling well. I have been successful in avoiding it so far. I need to find someone to ride with for church tonight since I’m the only one going.
I started on my resume the other night. The supervisor position isn’t going to get posted until my manager gets a new boss. Hopefully by the end of the month. It’s weird writing a resume to be a supervisor. Professional qualities are hard to not sound arogant. I’m excellent at this and that. Highly skilled at everything. They know who I am. They already know my strengths and weaknesses. The big question is can I be happy being a supervisor instead of a technician.
I’m working on a special project with a mechanic. Manufacturing puts room temperature batches of product paste into freezers. The freezer has to work to hard to bring it down to -72 Deg C. Eventually the freezer may never get down to the correct temperature or simply breakdown. There are about 20 freezers like that.
The mechanic’s solution is from an upgrade that sells for about $1100. We think it can be done a lot simpler and cheaper. Basically a seperate control circuit for liquid nitrogen (LN2) or Liquid CO2 back up. LN2 in liquid form is about -195 Deg C. When the liquid is exposed to anything above -195 it boils and produces an offgass in vapor form. That vapor can keep a freezer really cold. We only need it around -72 so it’s just a matter of controlling when the LN2 supply kicks in and stops.
Safety is a key issue and that’s where I come in. The mechanic asked me to figure out how to monitor several points in the process in order to present data. Monitoring temperture is simple because our recorder takes thermocouple inputs. Monitoring the status of an A/C solenoid valve is also easy since I had a cable made up from a previous application. The A/C signal turns on or off a relay. The relay contact is monitored as a temperature at ambient. Ambient equals valve on. Open contact equals valve off.
The next tricky item is monitoring the current through the compressor. I found a clamp on ammeter that outputs a proportional A/C milli-volt. The problem is the recorder doesn’t read A/C milli-volt. I need to convert it to DC milli-volts. I asked a few other techs that couldn’t give me any ideas. Of course lefty was able to send me down the correct path. I should be able to use a 9v battery to run a circuit. The circuit will be an op-amp set up with feed back to give a gain of 10. The output will be 10 times more than the input. It’s still an A/C signal at that point so I jus have to run it through a resistor and capacitor. The cap will charge to what ever the output is. That will give me a DC voltage to feed into the recorder. As the current through the clamp-on ammeter goes up, the out put will increase. My circuit will convert that into a DC voltage for the recorder. We’ll see next week.