The usage of a Hydrogen sensor

Hi all
My mainly question is about why we won't be able to detect Hydrogen as Ex. gas using IR technology sensors?
Also, I'd like to know if H2 would be detected using IR senosor?
I need to know what is the equivalent technology for this purpose too?
Thanks
Ay ElEbshihy
 

DrClaude

Mentor
6,807
2,922
I don't really understand all you are saying (what is an "Ex. gas"?), but I can tell you that H2 is transparent in the infra-red.
 

mjc123

Science Advisor
698
306
To be more specific, when a homonuclear diatomic molecule like H2 vibrates, there is no change in dipole moment, therefore nothing for an oscillating electric field (EM radiation) to couple with to cause absorption. So H2 doesn't absorb infrared radiation. (The same is true of O2 and N2, which is why we don't have a runaway greenhouse effect.)
 
I don't really understand all you are saying (what is an "Ex. gas"?), but I can tell you that H2 is transparent in the infra-red.
1st thank you for your reply
I mean in an Explosion proof area like petroleum sector companies
You explained that H2 is transparent in the IR so what is the another solution to avoid this point
Thank you
 
To be more specific, when a homonuclear diatomic molecule like H2 vibrates, there is no change in dipole moment, therefore nothing for an oscillating electric field (EM radiation) to couple with to cause absorption. So H2 doesn't absorb infrared radiation. (The same is true of O2 and N2, which is why we don't have a runaway greenhouse effect.)
1st thank you for your reply
What is the another solution to avoid this point
Thank you
 

DrClaude

Mentor
6,807
2,922
It shouldn't be hard for you to google "hydrogen gas detector"
 
646
163
IIRC, there's two temperature sensitive resistances, one coated with a catalyst, run side-by-side in a bridge arrangement. Catalysed, any hydrogen reacts with ambient oxygen, alters its leg's temperature and resistance, unbalances the bridge...

Similar tech checks for 'general flammable vapour', such as methane etc and toxic gas such as Carbon monoxide. But, because such are less responsive to ambient catalytic oxidation, they may need to be warmed. Think how car exhaust catalysers don't work well until hot enough.....

The extra circuitry and protocols for self-testing and maintenance of such safety-critical equipment is well beyond my amateur reading.

FWIW, some of our hydrogen-flame GCs had an internal leak sensor, which had to be replaced at service intervals as air pollution progressively poisoned the active surface.

Um, also Google 'Faraday Lamp'...
 

Astronuc

Staff Emeritus
Science Advisor
18,491
1,609
1st thank you for your reply
I mean in an Explosion proof area like petroleum sector companies
You explained that H2 is transparent in the IR so what is the another solution to avoid this point
Thank you
Honeywell makes a variety of gas sensors, including sensors for hydrogen. Catalytic and electrochemical sensors are used to detect hydrogen, and they require oxygen.
See Chapter 10, starting on page 36, and see Table on page 43 in
 

Want to reply to this thread?

"The usage of a Hydrogen sensor" You must log in or register to reply here.

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top