anyone familiar with high voltage high frequency modulate UV bacterial lighting?

[junkhound]

Any recommendations as to ballast suppliers or sources ?

1 kV, 400 MHz modulation, 1 kW or similar.

Thinking may have to design from scratch, would prefer to find something 'off the shelf'

 

[Ingenieur]

400 MHz
electrical operating frequency or UV spectrum freq???

there are companies who make uv disinfection unis for wastewater

UV light has frequencies ranging from 8*10¹⁴ to 3*10¹⁶ Hz (800 THz to 30 PHz)

 

[junkhound]

400 MHz
electrical operating frequency or UV spectrum freq???

there are companies who make uv disinfection unis for wastewater

UV light has frequencies ranging from 8*10¹⁴ to 3*10¹⁶ Hz (800 THz to 30 PHz)

The 400 MegHz (4E8Hz) is the modulating frequency of the nominal dc light power supply - light intensity is meant to vary at that high frequency. According to the literature, Bacteria DNA and other molecular structures of bacteria resonate at that frequency under far UV light and 'explode'. Apparently the modulation makes the UV a few hundred or thousand times as effective in killing bacteria vs. simple dc arc tube exitation, seconds of exposure kill the germs vs. minutes or hours. At least that is what the medical gurus say.

 

[gar]

161120-1605 EST

In the fall-winter time frame of 1946, just after I received my ham license, I gave a demonstration of my 2 meter transmitter and beam antenna at a Detroit amateur radio club meeting. This used either an 832 or 829 output tube. I think I used a surplus aircraft transmitter. I used a 20 W fluorescent bulb attached to nothing and hand held to demonstrate the beaming effect of a beam antenna. This was a qualitative demonstration by visually observing the bulb intensity. The ionized gas was effectively modulated at 2*144 = 288 MHz. I still have the antenna, and possibly somewhere the transmitter.

In a radio transmitter the final amplifier is operated in class C mode to obtain high efficiency, unless a linear amplifier is required.

What kind of a wave shape do you require? If a square wave is not required, then an approximate 1 kW 200 MHz transmitter might work to give you the 400 MHZ UV modulated light. Impedance matching, i.e., how you couple the transmitter to the UV tube becomes important.

At the power level you are talking about there is an RFI problem and the equipment would need to be operated inside a screen room. This is true whether it is a "transmitter", or some on-off switch.

.

 

[GoldDigger]

Some of the original publications seem lacking in detail, and I think I would have to do some serious searching to answer with any confidence.
One thing that needs to be clarified is just what the "same UV flux" means in this context.
If the average flux of the modulated waveform equals the average flux of the continuous waveform, it may be that the biggest contributor to the observed results is the higher peak flux of the modulated waveform.
It is not unreasonable that there is a threshold flux level above which biological damage increases greatly.
Possibly the amount of protein damage done before repair enzymes have a chance to do their work?

 

[JFletcher]

I'm guessing this is for WWTP disinfection. Check in that industry for suppliers of what you seek. I'm only familiar with the very basics as no HRSD plants had UV disinfection when I was an operator, and it isnt something the avg electrician would know either. Member Saturn Europa works at a WWTP; he may have some suggestions for you.

 

[Saturn_Europa]

Any recommendations as to ballast suppliers or sources ?

1 kV, 400 MHz modulation, 1 kW or similar.

Thinking may have to design from scratch, would prefer to find something 'off the shelf'

We use TrojanUV 3000 Plus. They can flow pace, meaning they can very wattage based on flow. Its a nice system and well supported from Trojan's offices in Canada. But dont forget your American Express. Its a very expensive product but very well designed and manufactured. Our system is fully automated with an AB Compact Logix that controls ballast outputs based on flow and turbidity. All the control boards and ballasts are repair by replacement, which can also get a little high after the 5 year warranty is up.

Is this for a home system or a research project? When I lived in Maine, I worked on a couple yatchs that used UV disinfection. They were fairly simple and inexpensive systems.