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Bronze06
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Simplified J valve operation/

Sun Jun 07, 2015 12:11 pm

https://youtu.be/BNMzWcltH4w

I know it is not up to Luis' level but it gets the point across. :D :D
"Where'd ya get that ol' thang, don't cha' know them thare things ill kill ya!"

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Re: Simplified J valve operation/

Sun Jun 07, 2015 2:19 pm

Great video. Clean and simple. Good job. Mark.
"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

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Re: Simplified J valve operation/

Sun Jun 07, 2015 6:17 pm

That's really good Russ. I may borrow that video, if you don't mind, for my class. There's a certain level of detail that most people need to know for everyday use,and this explains it really well. I liken this to the idea that you don't need to understand how Dell creates CPUs in order to use a home computer. 8)
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Re: Simplified J valve operation/

Sun Jun 07, 2015 6:25 pm

slonda828 wrote:That's really good Russ. I may borrow that video, if you don't mind, for my class. There's a certain level of detail that most people need to know for everyday use,and this explains it really well. I liken this to the idea that you don't need to understand how Dell creates CPUs in order to use a home computer. 8)
I emailed you about it, I'd like to find a way to incorporate it on the site for future reference. It's a subject that comes up quite a bit.
Doing it right should include some common sense, not just blindly following specs and instructions. .Gary D, AWAP on SB

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Re: Simplified J valve operation/

Sun Jun 07, 2015 6:28 pm

I stickied it for now. As things progress, perhaps this will be part of a new web page we create ;)
The impossible missions are the only ones which succeed. -JYC

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Re: Simplified J valve operation/

Mon Jun 08, 2015 5:51 am

Hey, Solanda/Ron

PM SENT :D
"Where'd ya get that ol' thang, don't cha' know them thare things ill kill ya!"

Live From the Red Sea,

Russ

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Re: Simplified J valve operation/

Mon Jun 08, 2015 9:37 am

A good demonstration however there is one point that is not made in that the J seat is not constantly held open by the high pressure, it cycles open and closed with each breath until tank pressure can no longer overcome J spring pressure which coincides with the reserve pressure. At that point air flow will stop or be restricted until the lever is moved down to release tension on the J spring.
Captain

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Re: Simplified J valve operation/

Tue Jun 09, 2015 3:29 pm

God this site is cool. I just learned another secret of valve operation I didn't know existed. Ron, with what the Captain said being the case, the Power Point can easily be modified to show this feature in the animation pane.
"Where'd ya get that ol' thang, don't cha' know them thare things ill kill ya!"

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Russ

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Re: Simplified J valve operation/

Sat Jul 18, 2015 12:23 pm

captain wrote:A good demonstration however there is one point that is not made in that the J seat is not constantly held open by the high pressure, it cycles open and closed with each breath until tank pressure can no longer overcome J spring pressure which coincides with the reserve pressure. At that point air flow will stop or be restricted until the lever is moved down to release tension on the J spring.

You can see this quite well of you use a reg set with an SPG. This happened to me with my boat tank and I had to put the valve in fill position to maintain my sanity. It is disconcerting to see a pressure gauge drop sharply on the air you are breathing no matter if you understand the reason. I have been meaning to try the SPG on a J-valve with an SPG port to see what happens, I assume it would not have the same effect however, its on my to do list.


Bob

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Re: Simplified J valve operation/

Sun Dec 04, 2016 9:30 am

BobDBF wrote:
captain wrote:A good demonstration however there is one point that is not made in that the J seat is not constantly held open by the high pressure, it cycles open and closed with each breath until tank pressure can no longer overcome J spring pressure which coincides with the reserve pressure. At that point air flow will stop or be restricted until the lever is moved down to release tension on the J spring.

You can see this quite well of you use a reg set with an SPG. This happened to me with my boat tank and I had to put the valve in fill position to maintain my sanity. It is disconcerting to see a pressure gauge drop sharply on the air you are breathing no matter if you understand the reason. I have been meaning to try the SPG on a J-valve with an SPG port to see what happens, I assume it would not have the same effect however, its on my to do list.


Bob

Here is the redux video link that shows all.
https://www.youtube.com/watch?v=U0_A0jsqyZs
"Where'd ya get that ol' thang, don't cha' know them thare things ill kill ya!"

Live From the Red Sea,

Russ

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captain
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Re: Simplified J valve operation/

Sun Dec 04, 2016 11:36 am

Maybe I am not on the same page understanding the how the operation is described in the video.
The only time the J valve is off the seat is during inhalation. As soon as inhalation stops the J valve returns to closed. Tank pressure of any amount can not hold the J valve off the seat at any time unless inhalation is taking place. A reverse way to visualize it is that the diver sucks the J valve open with every inhalation. Just like the regulator operation is based on diver demand during inhalation so is the J valve.
The video does not show the J valve returning to completely closed after each inhalation or when the the valve is initially opened and the regulator is pressurized. At that point once the whole system is equalized the J valve returns to the closed position.
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Re: Simplified J valve operation/

Mon Jun 12, 2017 5:07 am

captain wrote:Maybe I am not on the same page understanding the how the operation is described in the video.
The only time the J valve is off the seat is during inhalation. As soon as inhalation stops the J valve returns to closed. Tank pressure of any amount can not hold the J valve off the seat at any time unless inhalation is taking place. A reverse way to visualize it is that the diver sucks the J valve open with every inhalation. Just like the regulator operation is based on diver demand during inhalation so is the J valve.
The video does not show the J valve returning to completely closed after each inhalation or when the the valve is initially opened and the regulator is pressurized. At that point once the whole system is equalized the J valve returns to the closed position.
I know the video is a little wonky and yes the reserve valve should reset after each breath, but in general, the video gets the point across. I might re-visit it and fix that, as well as inform the audience that the reserve valve works through a reduction of back pressure behind the valve when the diver takes a breath.
"Where'd ya get that ol' thang, don't cha' know them thare things ill kill ya!"

Live From the Red Sea,

Russ

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Re: Simplified J valve operation/

Wed Jul 05, 2017 5:04 am

I have redone the PowerPoint presentation and have sent it to some of you guys. I will be getting a REDUX 2 video out on the tube sometime. Thanks Tom the "Captain" for pointing some stuff out that made a helluva lot more sense.
"Where'd ya get that ol' thang, don't cha' know them thare things ill kill ya!"

Live From the Red Sea,

Russ

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Bryan
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Re: Simplified J valve operation/

Wed Jul 05, 2017 8:19 am

Keep up the good work Russell Thanks for your help!
Doing it right should include some common sense, not just blindly following specs and instructions. .Gary D, AWAP on SB

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Re: Simplified J valve operation/

Wed Jul 05, 2017 11:24 am

Hey Russell,
Thanks for your work you do on these presentations. It's guys like you that help make this forum so helpful and informative for us all! :D
The older I get the better I was.

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