My finished equipment dryer.

[ronnychencharik 0]

Alright, for one of my classes the teacher has given us instructions to make something that is controlled digitally. My idea is to make an equipment dryer/sanitizer. What i really need is to know what humidity level the aforementioned machines reach that triggers them to shut off.

Ideally I would make the cabinet out of Plexiglas, throw in some fans for airflow and probably a heater. That is the most basic part of my creation, where it gets harder is the other aspects I want to throw in. I want to try and incorporate a dehumidifier and a humidistat that will be controlled by a PLC.

What I gather from shockdoctors and ozones websites is that they are a open loop system, running for a set amount of time and then shutting off. My teacher has a PLC that I will be able to use for this, but the real problem lies with the humidity level and being able to monitor it. So I guess my question is this: Should I run this as an open loop, or a closed loop system that depends on humidity levels?

If anyone has any experience with these machines, PLCs, or monitoring humidity digitally please let me know.

Thanks-

Ben

[Chadd 916]

An open loop system is less likely to break over time and I would think twice about adding heat.

[ronnychencharik 0]

It wouldn't be much heat, but why would you think twice about it?

[Chadd 916]

It wouldn't be much heat, but why would you think twice about it?

Without ozone or a chemical solution, adding heat will encourage the growth of bacteria.

Most bacteria thrive at temperatures at or around that of the human body 98.6°F (37°C), and some, such as Escherichia coli, are normal parts of the human intestinal flora. These organisms are mesophiles (moderate-temperature-loving), with an optimum growth temperature between 77°F (25°C) and 104°F (40°C). Mesophiles have adapted to thrive in temperatures close to that of their host.

http://science.jrank.org/pages/714/Bacteria.html

[Rustpot 1]

How big is this project? Are we talking a semester-long, budgeted project? If so, you're probably better off getting some teammates stanky equipment and doing several tests while varying your setup.

You could even incorporate an automated aerosol of something like FunkFree that sprays upstream of the equipment every minute or so.

The big three with bacteria are heat, light and moisture. They feed off humans and work best in dark, warm, wet environments. I think people have said that sunlight or directed light would be bad since it can degrade equipment plastics, so the other two will be your main concern.

Get the moisture out by blowing dry, room temperature air over the equipment. To kill the bacteria you'd have to bake the gear at 110+ F, which could probably lead to glue and plastic failure along the way.

As far as the apparatus goes, I think a good way might be to have an inlet on a dehumidifier, 4 ducts with 6" or larger fans that move air over the equipment from multiple angles, and a nice large box fan for exhaust. 1/16 or 1/8" polycarbonate with caulk would probably be pretty cheap and easy to make, with something like angle aluminum as a structural base.

[ronnychencharik 0]

How big is this project? Are we talking a semester-long, budgeted project? If so, you're probably better off getting some teammates stanky equipment and doing several tests while varying your setup.

You could even incorporate an automated aerosol of something like FunkFree that sprays upstream of the equipment every minute or so.

It will consume most of the semester, he wants it to be hypothetical but I think I am going to make it anyway. I might get some financial backing from my teacher's son (who's child plays hockey and is interested in my idea) but it will not be very much.

I considered the disinfectant idea but was stumped on what I would use and wasn't really sure if I could make an automated mister. The rubbing alcohol idea seems solid but to keep refilling it could be a pain. And making a system that runs on a servo motor pressing the aerosol can be costly.

[Wolfpack_1986 154]

nvm... misread initially...

edit:

to monitor humidity digitally, viasala makes dewpoint sensors, which %RH is a function of DP and Temperature. they also make insturment that do the calculation for you, but i'd suggest monitoring DP and using that. it's more raw data. However these instruments are costly, i'm sure there's other options, but for a theoretical exercise, you're good to go. The output could be monitored for your shutdown level, but that'ds involve software.

is this in college or highschool? a team thing or individual?

IMO, to get everything working how you want, you might be biting off more than you can chew... this would be a fairly involved build to do it correctly.

[ronnychencharik 0]

Its for college. I originally wanted to have it set up so it would run for a set amount of time, but my teacher seems to think that I should be monitoring the humidity levels.

[Wolfpack_1986 154]

well, the best approach would be to determine what environments are most capable of KILLING the bacteria. does it just throw it into a dormant state, or does it actually kill it.

[Rustpot 1]

well, the best approach would be to determine what environments are most capable of KILLING the bacteria. does it just throw it into a dormant state, or does it actually kill it.

It's technically quite hard to kill bacteria. Alcohol (isopropyl) or heat and pressure will do it, neither of which would be good for gear I would guess. The goal of airing out hockey equipment is to get them out of their optimal zone ASAP to slow or cease their multiplication.

You could work on a system where you rinse the gear down, monitor the humidity, and when you're no longer pulling moisture from the gear stop the cycle. Probably needs testing, though.

[Neal 41]

Its for college. I originally wanted to have it set up so it would run for a set amount of time, but my teacher seems to think that I should be monitoring the humidity levels.

I think the gear would still be considered damp long after the air inside your box was dry, especially if the air was flowing through. And the humidity would be read off the air. Unless you can figure out how to read the humidity level of the gear, I don't see the value.

[Wolfpack_1986 154]

well, the best approach would be to determine what environments are most capable of KILLING the bacteria. does it just throw it into a dormant state, or does it actually kill it.

It's technically quite hard to kill bacteria. Alcohol (isopropyl) or heat and pressure will do it, neither of which would be good for gear I would guess. The goal of airing out hockey equipment is to get them out of their optimal zone ASAP to slow or cease their multiplication.

You could work on a system where you rinse the gear down, monitor the humidity, and when you're no longer pulling moisture from the gear stop the cycle. Probably needs testing, though.

yeah, i know. I was running through solvents in my head as to what would kill without eating the gear... Ozone actually does it i believe, but like i said, finding the most effective thing to kill it would be prudent, even if you're nailing like 30% of them. (totally arbitrary numbers) At least that's what i assumed his end goal was.

[ronnychencharik 0]

I think what's going to end up happening making it a drying system where I can key in a set time and let it dry. The only thing that is bothering me right now is the cost of the dehumidifier.

[Wolfpack_1986 154]

check your pm, i have an idea...

[ronnychencharik 0]

First off, I want to thank puck_it for giving me the idea about using desiccant and two separate chambers as a basis for this.

My final product ended up deviating from the original plans, but I ended up converting an old refrigerator from work into my frankenstein equipment dryer.

After tearing out everything that I didnt need and sealing off the freezer from the fridge. There are two fans (that are somewhat difficult to make out in the second picture) which bring the moist air from the equipment chamber into the drying chamber inside the freezer, and then blow the dry air back into the equipment chamber. This is all controlled by a timer from an old dryer and will usually have my equipment dry in about an hour.

[dumbpolak9 1]

nice!! i would make one but no clue how to =P really bright idea.

[tjl_48 0]

So you decided against monitoring the humidity? I had a similar idea for a project I had in college but I was going to use a microcontroller to monitor the humidity and control a relay to turn the fans off. I just didn't have the money to go through with it though. And if you are still thinking about doing some PLC stuff I have some experience with that.

[ronnychencharik 0]

I ran into the same problem that you did with the whole money thing. Humidistats can be expensive and the PLCs are even worse. Overall i'm pretty happy with how it turned out.

[Law Goalie 147]

Brilliant work.

If you have time, I'd love to see a parts-list and a rough building plan.

This might also be an ingenious way to secure one's equipment in a public space: just add a latch and lock to the door, bolt the sucker to the floor, and you've got yourself a self-cleaning hockey locker.

Just FYI, Isopropyl alcohol is entirely safe to use on hockey gear. I've gone through this in great detail, and a 60% solution is apparently optimal. The only things that in theory you shouldn't spray it on are glove-palms or any other porous synthetic or natural leather, but even those are probably fine. DON'T use a rubbing alcohol that contains hydrogen peroxide.

You wouldn't even need an automated mister. Just arrange the items in the locker so that you can spray them individually, keep a bottle handy, and spray away.