UV flame scanner bulb/tilt switch used as safety-need circuit help

[Rezaxis]

I have a flame scanner made by UV-eye, just the bulb part. It consists of a UV sensor bulb with a 1K resistor (looks like 1/2 watt) on each leg, and two 600V wires/leads. As far as I can determine, it takes a minimum of 560VDC to make it conduct. I think it's rated at 600V, it's suggested that 600V rated wire be used to connect it. But I don't know the current ratings. UV Eye part number 4-314-1 for the bulb and UV1a is the part number for the scanner assembly. I can't find any other info.

As far as the bulbs operation: It has a rarified gas inside. If enough voltage is applied the bulb "avalanches" (conducts then opens) repeatedly depending on the intensity of the UV it senses. The more flame (UV), the more pulses per second. I found a similar circuit using a different product at the following link, if that helps

https://www.electro-tech-online.com/custompdfs/2006/08/R2868.pdf

If anyone looks at that link and sees the circuit, can you tell me what the two capacitors that parallel the input and output do? The bulb I have doesn't seem to have a cathode/anode designation on it, or any other markings either. It doesn't look polarized to me.

I can supply the the whole safety circuit with 120VAC at 9.5A. I want to use it as a one safety to interupt 120VAC going to an emergency gas shutoff valve that requires 120VAC at 0.12A to remain open. For my application I just need to know if a flame is present or not. I would like to be able to bypass this flame sensor, it's output or the controlling device, during initial startup (the emergency gas shutoff valve must be open, supplied with 120VAC, but no flame would be present till I manually light it, after which I would manually switch the UV scanner into the circuit so it acts as a safety.)

I would also like to put the UV scanner (flame on/off) safety in series with an omni-directional tilt switch of some kind that would open the 120VAC going to the same gas shutoff valve. So, if the flame goes out the gas shuts off, or if the unit tips the gas shuts off.

I am looking for a normally closed omni-directional mercury tilt switch that will handle the current requirements of the emergency gas shut off valve.

So, in a nutshell if I got it right, it looks like I have to step up 120VAC to 1200VAC, rectify and filter to 600VDC, apply this with proper current limiting to the bulb, voltage divide properly, then filter the scanners output pulses and somehow control a devise (relay?) that would interupt 120VAC to the emergency gas shutoff valve.

Oh! and I'm a new forum member so Hi everyone and thanks to all who look and many thanks to any one who might help.

Rezaxis

 

[hjames]

When dealing with these types of components, it definitely is polarized - electrons are knocked off when photons hit the relatively solid cathode and fly to the grid-like anode. Unless the inside of the bulb is very symmetric, I'd be ready to test the bulb in both orientations to see which one is more sensitive.

In the circuit you included, the important thing to look at is the 10M resistor in front of the capacitor. Those two should heavily filter the power supply, and I'd guess that they also determine the maximum pulse rate. I'm also guessing that if those weren't there, the bulb would probably be damaged. For the Hammatsu part, it wants a 100uA average current, so if the bulbs are about the same size, I'd check the voltage of your bulb by increasing the voltage applied until I see it passing 100uA. Is this what you measured? Biasing above 1mA would probably damage the part.

I'd guess that the output cap is just there to filter the signal a bit (instead of trying to look for nano/micro second duration spikes.

I don't have any experience selecting tilt switches, so you'll have to poke around a bit...

I think you can do with a simple capacitor/diode voltage multiplier on the 120V, preferably after its been isolated by a transformer. You'll need some electronics to try to regulate the high voltage, as well as some RC filter and a transistor which turns the relay off when some pulse/sec threshold has been exceeded.

James

 

[Rezaxis]

Thanks James I'll look into the voltage multiplier and I'll keep looking for a proper tilt switch. I didn't measure anything on the UV scanner bulb, just looked at it under magnifiction. It has two filiments inside the bulb that are identical. They just come up into the bulb and turn at right angles, paralleling each other but not touching. The two 1K resistors on each terminal make it very symetrical product. No plate at all like the product in the link. I agree with the 10Mohm resistor. Very small currents would seem appropriate. I don't have a way of applying varying voltges to the bulb unfortunately. I can't seem to locate ANY information on this bulb. It has absolutely no markings. The Japanese product web site offers both their bulb and the driver card for $80. I may go this route. I really just need an inexpensive way to prove flame and interupt 120VAC accordingly. I got this bulb for nothing and I thought I could use it. Maybe it's just not worth the trouble. Thanks again.

Rez

 

[PrecisionMarine]

Rezaxis, I know I'm replying to a very old post, but if you should still happen to have the 4-314-1 bulb and not used it, I'd be interested in purchasing to help me resurrect an older peice of equipment.
Thanks,
PM