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Dewyuck
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Registered: 09/30/18
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DIY Automatic PC Sterilizer
#26621248 - 04/22/20 11:43 PM (3 years, 9 months ago) |
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Quarantine has me feeling a little lonely so I figured I’d share my hacked PC.
So after trying and failing at building a 55 gallon pressure sterilizer, I decided to go with my backup plan for the time being. I took all the components and retrofitted my 22qt stovetop PC to make an automatic electric sterilizer.
It’s not pretty but it works.
It now no longer needs a stove considering it has an electric heating element. Also the pressure and temperature are controlled by a digital controller. If the temp gets too high it will send a signal to open the solenoid release valve and turn off the heating element.
It manages the temperature surprisingly well. I have it set to vent at 122°c. During its last run I think it vented once for about a second. It also never went below 121°c (250°f)
My goal was to make something I could plug in, set a few numbers and not have to tinker with it until it’s done.
A last addition may be a timer to shut it off at the end of a cycle. But that’s if I get more lazy than I already am!
I guess years of studying and fixing audio equipment finally payed off.😅
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c10h12n2o
serial dilutor



Registered: 01/21/15
Posts: 3,200
Loc: the abyss
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Re: DIY Automatic PC Sterilizer [Re: Dewyuck]
#26621255 - 04/22/20 11:55 PM (3 years, 9 months ago) |
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That's dope
Can you share more details of how it works and was constructed, parts etc?
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Ryan_Spalding2727
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Re: DIY Automatic PC Sterilizer [Re: c10h12n2o]
#26621330 - 04/23/20 01:34 AM (3 years, 9 months ago) |
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Ingenuity at it’s finest! Lol, good work.
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poisoned
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Registered: 04/17/13
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That's awesome. You should make it 100% automatic. Set the autoclaving time and it automatically heats, vents, pressurizes for the set amount of time and then shuts off.
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brikogen
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Re: DIY Automatic PC Sterilizer [Re: poisoned]
#26621453 - 04/23/20 03:45 AM (3 years, 9 months ago) |
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Looks cool man. I was thinking of doing the same with my "dumb" autoclave which is already electric. Instead of letting it vent out I want it to shut off before it does that as the vent sounds terrifying. But drilling and modifying it seemed daunting.
So I just bought a 10$ Gosund WiFi smart socket and timed the cycle going on and off using the pressure gauge. So then I could create an automation using the app to turn on the autoclave for x seconds and turn it off for y seconds. It's simple and surprisingly accurate and have yet to hear the vent go off. And an added bonus feature is that it measures kWh so you know how much energy is being consumed if you want to know overall running cost of your operation.
Edited by brikogen (04/23/20 04:43 AM)
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Dewyuck
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Re: DIY Automatic PC Sterilizer [Re: c10h12n2o]
#26624084 - 04/24/20 07:44 AM (3 years, 9 months ago) |
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Hey c10, sorry for the delay. I’ve been busy sterilizing haha I’ll add some close up pictures of the components with explanation. Thanks for the interest!
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Dewyuck
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Re: DIY Automatic PC Sterilizer [Re: Dewyuck]
#26624260 - 04/24/20 09:32 AM (3 years, 9 months ago) |
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Thanks for all the compliments and interest everyone! Here is a list of components with prices and explanation. I bought everything on Amis on except for the original PC which I got at a thrift store.
1) a generic Rex c-100 pid controller - about $15 This controls a heating element and solonoid valve to release excess pressure need be. I’ll go into more explanation below. These are made by a million different Chinese companies. I think the original was Japanese but just read reviews. I don’t believe the one I initially bought is available any more. The biggest issue was finding the correct manual so I could program it properly. And by program I simply mean change parameters so that it does what I want. Someone far more knowledgeable can explain this on YouTube or something ha



2) DERNORD Immersion Cartridge Heater 120V 1500W 3/4 Inch Thread -$30 obviously this heats the unit but it definitely has the most complicated setup out of all of the components. The main ssr output from the controller is attached to a relay that then either closes or opens the circuit to the heating element
3) T-PRO K-Type Thermocouple Temperature Sensors 2M/6.6Ft Wire,Stainless Steel Probe 100mm with fixed M8×1.5mm thread -$8 you cant see this well because most of it is within the pressure cooker. It is the spring looking thing with the metal breaded wire sleeve. This is attached to the pid controller so it can regulate the temperature. Pretty straight forward
4) DC12V 1/4" NPT High Temperature Resistance(23-356℉) Brass Electric Solenoid Valve Normally Closed -$18
The solenoid is powered by a 12v power converter from the alarm output of the controller. The alarm output acts as a normally open relay (no current unless on). When the temperature rises above the set alarm threshold, it allows current to pass to the solenoid valve. It then releases pressure which also decreases the temperature. I’ve noticed this may be unnecessary and does has not had to release pressure during a run since adding the heating element. Previously, before I got the motivation to drill the hole for the heater and was still using it on the stove, it would activate about once per minute. I also added a little loop pipe from a steamer and a t connector stuffed with poly file to deaden the noise when it releases. Not really an issue anymore.



5) ALITOVE 12V 5A 60W Power Supply Adapter Universal Regulated Switching Transformer AC110V to DC 12V 5amp -$12
this is for converting your typical wall outlet voltage to the 12v needed for the solenoid. Had I bought a 110v solenoid this would not be needed. However i didn’t like the idea or running a cable with high voltage across the top of the cooker where it could potentially melt, then short on the pot, then kill me

6) 3-32V DC to 24-480V AC 40A Output Single Phase SSR Solid State Relay -$11
I replace the original with this higher amp one. The original one also came with a heat sink which apparently is pretty crucial in extending the life of these. The SSR (solid state relay) is essentially like flipping a switch. The only difference is that instead of using your finger you’re using the 12v of electricity supplied by the SSR output on the pid controller. The controller sends the 12v to the SSR when the temperature is below the set threshold. On the opposite side of SSR a wire is connected in series with the negative side of the load wall supply power. Then to one contact of the heating element. The other contact of the heating element is wired directly to the opposite supply line, skipping any relay or resistance s

7) Winters PFQ Series Stainless Steel 304 Dual Scale Liquid Filled Pressure Gauge with Brass Internals, 30" Hg Vacuum-0-30 psi/kpa,2-1/2" Dial Display, +/-1.5% Accuracy, 1/4" NPT bottom mount
once I realized this valve has to be vented when the cooker is up to temperature it does a great job of measuring the pressure. You vent it by pulling and replacing the little brass plug on the top of the gauge. Equally great is it’s ability to measure the cookers ability to hold a vacuum. Unfortunately this does not hold a vacuum for very long after cooling. I could probably seal all of my components with high temp silicon, but I just haven’t gotten around to it yet. Also a new lid gasket would probably be helpful.

8)) An extra pressure gauge attached to a lever ball valve
this is to release the pressure/vacuum after cooking. Also the gauge is really a fail safe Incase the main gauge is blocked and to compare so I can be certain that my reading is correct. I typically place the cooker in front of my hepa flow good while it is still pressurized and before it creates a vacuum. This way, knowing there are slight leaks, any air pulled in during this process will be filtered through my flow hood and 99.98% free of contaminants.
9)) Various pipes and fittings and holes which at this point I’m not sure which ones were original and which ones I cut
10)) the original pressure cooker was an aluminum mirro 22qt but any similar should work fine. Steel should work but I imagine it would be a pain in the ass to drill holes in
** Like Poisoned suggested, I would like to add a timer that cuts the power after a specified amount of time. However I would also have to be certain that it is 100% air tight with absolutely no possibility to pull on outside air. I just don’t trust my glue it together approach enough to guarantee I can achieve this. Maybe when I build my next version that doesn’t look like a crazy person’s makeshift bomb I’ll add a timer haha
Here are a few more pictures of the whole thing sitting on top of my failed 55 gallon sterilizer experiment.

*** If you have any other questions on specifics hit me up and I’d be glad to include a poorly drawn schematic
Lastly if you do decide to build one do so at your own risk. I’m sure that drilling too many or misplaced holes could weaken the structural integrity of the PC thus...boom. That being said, have fun!!
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verum subsequentis
seeker of truth



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Re: DIY Automatic PC Sterilizer [Re: Dewyuck]
#26624465 - 04/24/20 11:07 AM (3 years, 9 months ago) |
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Damn. Good work. What do you think the total costs and amount of time put in equal? If it's anywhere near the total energy required to order an AA sterilizer if just suggest going with that. I may revisit this when it comes time for me to make a huge one though.
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Dewyuck
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Registered: 09/30/18
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Last seen: 10 days, 7 hours
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Thanks my man, I really appreciate it. I would say total cost should be less than $150. Even cheaper if you already have a PC. And if you understand basic circuitry and have the tools I’d say you should be able to build it in a day or two . Definitely cheaper than the AA. That was honestly my main reason for building it. I have since seen some electric sterilizers on eBay for about $150-175, so I’m considering getting one of those and adding the controller and such.
Side note I’ve run 4 batches in it so far and not a single melted or under sterilized bag. I use the sterilization indicator tape to make that assumption.
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