Electronics > Projects, Designs, and Technical Stuff

Cheapest way to check if a UVC bulb is as advertised?

<< < (3/9) > >>

thm_w:
You can buy air filters with germicidal bulbs installed https://asept-air.com/ca/shop/life-cell-1550-uv/
Any sort of replacement germicidal bulb from a genuine company is going to be legit, something like this for example: https://www.amazon.com/Ultraviolet-Water-Purifier-Bulb-Sterilizer/dp/B07K7Z1P63

These are ridiculously powerful and should not be operated outside of a good light sealed chamber, eg stainless steel.
They also heat up fast, and UV output can drop if the bulb overheats, not to mention burning up.

digikey has UVC photodiodes, if you want to measure the true output.
There were some digital sensors as well but it looks like the one I was looking at will not work, germicidal peak is 270nm this one measures 350nm peak, but others may exist: https://www.vishay.com/docs/84277/veml6070.pdf

Be incredibly careful with skin or eye exposure.

Someone:

--- Quote from: pipe2null on April 03, 2020, 10:46:21 am ---"Ideally", I'd like to know what wavelengths are actually emitting, and how much [energy] is actually being emitted at 254nm UVC.  It would also be useful to measure the same info for replacement UVC bulbs for normal commercial products as well.  Also, even if 254nm exist, also would like to verify that no lower wavelengths are emitted that produce ozone.

But that's "ideally".  :-DD   Is there a cheap way to do this?
--- End quote ---
Cheaply quantifying spectral energy, not really possible. Doing it below 300nm, another order of magnitude more expensive at least. Without an accurate and stable spectral output the cheap methods to quantify energy are all useless.

Ian.M:
There's no real problem working with UVC bulbs so long as you aren't stupid.  When I built an EPROM eraser using a 4W T5 UVC tube, I started off with a 4W fluorescent torch which had a Royer converter driving an ordinary white 4W T5 fluorescent tube, and did a quick check it was compatible with the UVC tube I had bought 'Big Clive' style, switched on and observed from the other side of the room - Inverse Square law is your friend, and *DONT* stare at it!

Then I built an enclosure with a draw with a black felt light seal  and antistatic foam for the EPROM(s), a draw interlock microswitch and a timer and status indicators,  with aluminum foil tape to protect various plastic parts from UVC degradation, and tested it with the visible white tube.  The UVC tube didn't get refitted until I was 100% satisfied with the control electronics, and that there was no significant light leakage (by observation in a dark room).

Re: the OP's UV intensity comparison problem, probably the cheapest hobbyist friendly option would be to time the 'bit-rot' of a UV erasable EPROM.  Program it all '0' then time till half the bits have become '1'.  However you mustn't apply power while the EPROM is being exposed to UV, so its going to require you to rig up some sort of servo controlled shutter to obscure its window while you are powering and reading the EPROM.

Otherwise, if you want a better measurement of optical intensity vs wavelength,  its DIY optics bench territory - build a spectrometer with a fused quartz prism rotated by a precision servo with a high sensitivity wide-band photodiode as the detector, then calibrate it using a source with a known spectrum and intensity e.g. direct noon sunlight at (near) sea level on an absolutely cloudless high pressure summer day.  Be prepared to move the photodiode further from the prism to reduce the intensity (inverse square law again).  Stray light is your absolute enemy - in addition to a light tight enclosure with a matte black interior, you'll probably want tubes with the best optical flat black coating you can afford round the optical paths, and inner enclosures with the same coating round the prism and detector.

mikeselectricstuff:
Smell of ozone. 

jpanhalt:
Are you sure ozone doesn't require a shorter wavelength? 

Low pressure mercury lamps in quartz envelops do produce ozone, but that is mostly from the small amount of shorter wavelengths they produce. https://www.oxidationtech.com/ozone/ozone-production/uv-lamp.html

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod