I am working on some basic automation and thought I would share. Consult with your professional engineer regarding your hazardous location.
NFPA/NEC codes require special construction for electrical circuits but certain low power devices can be made intrinsically safe with the use of a barrier device. So a 4-20mA pressure transmitter or mV thermocouple can be in the haz loc and be connected to a control system input in the unclassified area. Arlyn scales offer a barrier and 4-20mA output from their scales. I use automation direct because I can’t afford Allen Bradley or Siemens.
There is the stuff to get a type T thermocouple into 1/8" npt and out to a thermocouple barrier. Remember thermocouples require the same metal all the way to the mV reader or mV analog input card.
Next on my list is valve automation. Valve actuators are actuated via compressed air or nitrogen from solenoids outside the haz loc.
Intrinsically safe wiring can be used for almost everything you need on a closed loop. The only thing I am running on my automation that is above the limits of IS is a ultrasonic level switch. Even then the way i am running that switch is within IS but the equipment itself doesn’t come with that certification.
Valveman.com has the cheapest Iso5211 valves and actuators I have found, If you buy them separate and attach them yourself that is. They even have compression versions. Engineering consultants want you to add explosion proof limit switches to confirm the valve position. I have found cheaper and simpler ways to detect errors in this regard but the limit switch is definitely the most accurate and reliable.
Our Luna does NOT have limit switches on any of the valves…and can still figure out if the valves haven’t actually done what they were asked to do. Or at a min raise it’s hand and ask the operator to figure out what’s going on.
I’ve been doing something similar. I have automated timed extraction cycles with vac down and CRC. I need to install a few more valves so i can do more processes at the same time. I need to test volume based extractions with a level sensor when i get some more time. I got continous butane LLE working, but have since been using those valves for extraction programming.
Oh wow, that is impressive. Even looks like E&H (Endress Hauser) instruments, one of my favorite instrument brands. I want to put two E&H Coriolis flow meters on a bho rig to real time measure flow, temp, and density. Know yields before the solvent is evaporated.
Thanks for the valve suggestions and heads up on limit switch valve position feedback. Why automate and what? The c1d1 sensor and vfd controls became to complex for relay control, so I added a plc panel. Fast forward a couple months and I’m rebuilding the brand new PX1 into a 60 pound a shift setup and need auto “punisher” pump control to avoid pulling vac and pulling compressor oil into hydrocarbon circuit. Why stop there, so I’m automating everything that makes sense to me. Auto vacuum pump control next, with a pressure sensor, the pump auto start stops. I put a TV on the wall outside c1d1 with a headless HMI. Eventually I can afford a $1600 mouse to drive the HMI from inside the c1d1.
We did some testing with a Micromotion meter on a hydrocarbon setup. Even had help from them on the density curve chart and could not find consistent data from the meter with the charts we were running.
The meters and solution are very sensitive to phase change affecting data outputs. I have some ideas for when I get another chance to test. If you end up with a meter let me know and I can share some info!
I built a manifold which provide push and pull to all vessels, so you can cut the pump at the valve site instead of controlling with a vfd. if you have a vacuum inlet to this manifold you can put a short delay timer on the vacuum valve and wire the pump relay to the same digital output as the vacuum valve
I try to go with pneumatic whenever I can for valve actuation in C1D1 spaces.
Love what you did with making things swagelok doesn’t have. I’ve found that going into a Compressed Air flushed box a little easier than making all the tiny connections. But that’s just cause I like to be able to calibrate my indicators and sensors - and to do that I need to take them off a little more often than some of the fittings listed here allow.
I have a hammer mill, sock packing machine, and so the final frontier was the closed loop. the entire system is HMI controlled and monitored. The computer auto reloads solvent, has a solvent cooling cycle using a heat exchanger and an expansion valve, and runs all 4 tubes one after another transferring each run to a honey pot. Basically you clamp down and press start, but i have parameter input window for solvent temp, THC mole fraction, weight of gas to run, number of tubes to be ran, hot gas temperature, depth of recovery, soak time. The only thing I didnt automate was the pouring…I tried and it was always messy lol
You could automate the pour if you have a miner manifold and loadcells on your collection. Automate the venting of the miners and you have everything but column packing covered. Recently, I’ve had invasive thoughts of an auger feeding a column packer and 6" pneumatic ball valves for pushing biomass plugs in and out of a column.
I’m just a humble mids pumper, I have no need for miners yet, though that would be dope. Finally put the mole fraction program to work. Im curious what you are envisioning a with regards to the 6" valves. Thanks for the compliment
For the packer, I’m envisioning a 9’ ram that packs a 4’ long plug in a column with several strokes. Once the plug is made, 2 6" valves open and then the plug is pushed into the 4’ extraction column by the ram and the valves close. After extraction, the plug is pushed out by the next. There would need to be some sort of spacer to keep the valves from fouling.
I wouldn’t be surprised if a continous feed could be accomplished with the right peristaltic pump. I think we’re a bit away from seeing that anytime soon.
if someone could engineer some brick shit house rotary airlock that feeds a screw conveyor inside a soxhlet or something. continuous feed has been done just not at butane pressure as far as i know
