UV led's as a starilizer

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portabuddy

Candiru
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Nov 16, 2006
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well i was in my lfs a while back thinking about getting a uv sterilizer for my community tank and these things are horably expensive, i can get 50 of uv 10mm 15k mcd led's for about $10 and use some acyrilic i have laying around and make one for a lot less.

but my question is will these do the job? they are the same wavelength of light as the normal uv bulbs about 600-650nm and in my opinion they are more intense...

I posted this on another site about using it on my pond application without a clear answer, for that i was thinking about using 1000 of them(about $150).

this is what i was thinking of, let me know what you think.
13243.JPG
 
i'm pretty sure it'll work. LEDs last for something like 10,000 hours of continuous use. I would put led's on both sides of the long side of your diagram
 
Howdy,

The main question is: Does the acrylic absorb UV light or let it pass? You can shine as much UV at the container, but as long as its wall absorb the important wavelength, then it won't work.

HarleyK
 
good point harley. for a moment there i was considering making a diy UV steriliser. looksl ike i'll just go out and buy one. Thx
 
what about drilling the acrylic and flushmounting the LEDs into the surface?
 
Actually, uv sterilizers run at about 253-254 nanometers. Also I have been in alot of hospitals and such that use uv sterilizers and they are all ultra violet flourescent style bulbs. I would think that if they can make a LED that would destroy bacteria and viruses that hospitals would use them.
 
UV LEDs are available in 247nM to 365nM wavelengths and strengths of 1 to 1.5watts with the higher strength LEDs being available for medical lab use (and more expensive). The more abundant UV LEDs of the 247nM range are half the wavelength needed to immobilize a single bacteria (540+/-15nM). And, the strength of the lamp needs to travel through something other than vacuum or air to be effective. LEDs don't have the wattage range to maintain strength through water. This requirement restricts the size of the plumbing for such an impliment and it's restriction, in turn, will also limit the water flow through its system. An effective sterilizer requires the strength (wattage) to be effective through plumbing that's proportioned to be able to handle the entire volume of the system. That's where the dwell time (UV ray to water contact duration) comes into play. The reason manufacturers are using the longer style of lamp is to aid in increasing the dwell time. Germs in the water column are in constant contact with the UV source with the longer-style lamps. In an LED arrangement, the dwell time would be interrupted in the space between each individual LED lamp. The turbo-twist style is the current best method of achieving the correct wattage to dwell time combination.
The use of UV LEDs would require large enough numbers of these 1 watt lamps that you'll lose effectiveness and compactness in constructing a workable enough layout to make LEDs economically feaseable. Not to mention that these individual LEDs would require an elaborate voltage controller to prevent a cascading power shift each time a single lamp should cause a short or go out.
 
Doesn't seem like cost is a problem if your spending $150.00 on LEDs let alone a power source. (Tho I would like to see someone else wire up 1000 LEDs)

Oddballs right.

You could buy the lamp and make your own if your a diehard DIYer like me.

Dr Joe

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thanks for the reply, this made for good, interesting reading. Well i checked with my local plastics place and they confermed what a quick goolgle search gave me they said that stardard acyrilic/lusite/whatever lets through 93% of all uv light unless otherwise specified/treated, so this will let through the uv rays, now i was planning on drilling holes in the right hand side and flush mounting them in there so the led contacts the water, the reason for the bafles was to allow for more dwell time, interesting point on the strength though, the ones i got are 10000mcd, 20mA, 3.6V leds that, i could have used this info befor i placed my order(i got 50 among other leds i got) it didnt cost me much and i was going use a old 1.5A 12V laptop power suply for this.

the only problem is that they are 400-405nM not the 253-254nM you guys recomend, this is almost a quarter of the recommended wavelength, but it is around that of the uvb that water treatment plants use to sanitize drinking water, i was going to make it longer then shown in the crappy paint drawing and wrap everything all around in reflective mylar since its cheap/avalible and it reflects 98% of all light, mirrors are a tricky thing since the glass they use absorbs uv light and mirrorized plastic is expensive.

but since the wavelength is off I guess there is no reason to continue?, right or will it work still? i kind of want to make this work because i have pretty buch everything laying around from other projects(except for the led's, but now i have those too).


and BTW i would hook up 1000 leds if a had to and solder resistors to eack and every one, im just that nutz.

and i am a die hard diy'er if i can make it rather ten buy it i will, and as far as buying the lamps goes, they are expensive... unless you guys know there to get some cheap?
 
How many watts are you looking for for your UV? My LFS has the turbo twist pond 9W for $100.
 
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