Everything Leaks
Sep 4, 2020 16:40:26 #
I recently took a class on vacuum technology. One of the topics was leak detection using helium and the point was made that "everything leaks". He is a noble gas, while common in the universe, it is not common in the atmosphere which could interfere with the detection process. Also the element is the 2nd smallest and can make its way through a small hole.
That got me thinking about cameras and lenses. The best lenses use argon, also a noble gas and a large molecule, to fill the space between the elements. The question is how long can be expected before the gas can become contaminated with atmosphere?
We all know removable lens cameras will build up dust and obtain a film (no pun intended) on the sensor even if you never remove the lens.
That got me thinking about cameras and lenses. The best lenses use argon, also a noble gas and a large molecule, to fill the space between the elements. The question is how long can be expected before the gas can become contaminated with atmosphere?
We all know removable lens cameras will build up dust and obtain a film (no pun intended) on the sensor even if you never remove the lens.
Sep 4, 2020 16:57:24 #
Doyle Thomas wrote:
I recently took a class on vacuum technology. One ... (show quote)
Interesting question. The argon must be at some slight pressure above atmospheric. With current technology a remote pressure sensor could be placed in the lens. When the pressure drops to atmospheric you can you can start to consider internal contamination.
Sep 4, 2020 16:59:03 #
Yup.
I always thought it quite interesting that the space between balloon rubber molecules is larger than helium atoms. That's why all the helium leaks out of a rubber balloon over time. The other air atoms are larger and don't squeeze through the balloon as easily.
Sep 4, 2020 18:20:35 #
I didn't know that the space between the elements in a lens were filled with Argon gas. Is that only the best lenses? What do cheaper kit lenses have?
Sep 4, 2020 18:25:01 #
There is an old saying: there is no such thing as hermetic, it is only a matter of rate.
Sep 4, 2020 18:27:43 #
Longshadow wrote:
Yup.
I always thought it quite interesting that the space between balloon rubber molecules is larger than helium atoms. That's why all the helium leaks out of a rubber balloon over time. The other air atoms are larger and don't squeeze through the balloon as easily.
Yup.
I always thought it quite interesting that the space between balloon rubber molecules is larger than helium atoms. That's why all the helium leaks out of a rubber balloon over time. The other air atoms are larger and don't squeeze through the balloon as easily.
Yes. And Hydrogen stamps are even smaller. Hydrogen is used for fine leak testing.
Sep 4, 2020 20:25:50 #
JD750 wrote:
Yes. And Hydrogen stamps are even smaller. Hydrogen is used for fine leak testing.
Not stamps!! Atoms!! 😖
Spelling miscorrector got me. 😡. That’s a good one! 😂 I keep a list of good ones, this one will get added to the list.
Sep 4, 2020 20:31:56 #
JD750 wrote:
Not stamps!! Atoms!! 😖
Spelling miscorrector got me. 😡. That’s a good one! 😂 I keep a list of good ones, this one will get added to the list.
Spelling miscorrector got me. 😡. That’s a good one! 😂 I keep a list of good ones, this one will get added to the list.
I knew what you meant! But that's s good one.
(When spall chunkers first came out, I was writing a letter to the Barclay Woods HOA.
It wanted to know if I meant Broccoli.......)
Sep 4, 2020 20:39:15 #
Longshadow wrote:
I knew what you meant! But that's s good one.
(When spall chunkers first came out, I was writing a letter to the Barclay Woods HOA.
It wanted to know if I meant Broccoli.......)
(When spall chunkers first came out, I was writing a letter to the Barclay Woods HOA.
It wanted to know if I meant Broccoli.......)
😂
How about liar for lawyer? That was one of my favorites!
Sep 4, 2020 20:48:39 #
JD750 wrote:
😂
How about liar for lawyer? That was one of my favorites!
How about liar for lawyer? That was one of my favorites!
Ummmmm..... Synonyms? 🤔🤪
Sep 4, 2020 21:30:28 #
JD750 wrote:
Not stamps!! Atoms!! 😖
Spelling miscorrector got me. 😡. That’s a good one! 😂 I keep a list of good ones, this one will get added to the list.
Spelling miscorrector got me. 😡. That’s a good one! 😂 I keep a list of good ones, this one will get added to the list.
My worst spell checker faux pas was an email to our head of System Engineering, a guy named Diptish Data. After the spell checker finished, the salutation read: “Hello Dipshit”. You can’t make this stuff up.
Sep 4, 2020 22:15:00 #
TriX wrote:
My worst spell checker faux pas was an email to our head of System Engineering, a guy named Diptish Data. After the spell checker finished, the salutation read: “Hello Dipshit”. You can’t make this stuff up.
😂 I’m sorry but that is funny!!
Sep 4, 2020 23:39:54 #
Sep 5, 2020 03:41:38 #
CO wrote:
I didn't know that the space between the elements in a lens were filled with Argon gas. Is that only the best lenses? What do cheaper kit lenses have?
Sewer gas.
Sep 5, 2020 05:03:48 #
Doyle Thomas wrote:
.....The question is how long can be expected before the gas can become contaminated with atmosphere?....
The gas doesn't have to be pure to achieve the intended effect. The main thing it's doing is keeping oxygen out, and even after contamination the gas will still have a diluting effect on the oxygen. The contamination process will be very slow and gradual. Some foodstuffs have pure nitrogen within their packaging for a similar reason. And people who have alloy rims on their cars can inflate the tyres with nitrogen to extend the life of the rims because oxidation along the sealing surfaces can cause the tyres to deflate.
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