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gioarmani

Why Have A Helium Escape Valve?

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The purpose of an HEV (Helium Escape Valve).

Certain watches designed primarily for prolonged, deep sea diving (e.g., the Rolex Seadweller, Omega's Planet Ocean & Seamaster, etc.) come with HEVs, generally located on the left-hand side of the case, opposite the crown side.

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Air cannot be used for deep-sea dives, since nitrogen (the primary constituent of air) becomes toxic at a depth of 60 meters (aprox. 197 feet, below sea-level). Therefor, when carrying out work at great depths, professional deep-sea divers stay in a bell (above water) for several days, breathing a mixture of gases, containing a high proportion of helium (instead of nitrogen). The pressure is gradually increased inside the bell to equal the same pressure at the working depth below. The divers--still inside the bell--are then lowered into the water, and down to the working site. Only then are they safe to leave the bell & perform their work.

Once their work is complete, they re-enter the bell, which is then raised back to the surface. After emergence, the pressure inside the bell is then lowered (returned back to atmospheric pressure) and it's during this stage that the HEV must be opened. This is the only proper time an HEV should ever be opened--only for deep-sea dives lasting for several days. Opening an HEV after regular swims and dives is essentially pointless, and does nothing for the watch. However, if your HEV valve is opened while you're in the water, you'll run the risk of flooding the movement with water, ruining the watch.

Once opened, the helium molecules diffuse and then penetrate the material of the gaskets. If not released via the HEV, the quantity of internal pressure inside the watch--after prolonged deep-sea exposure--is sufficient enough to explode the crystal out of the watch during the de-pressurization of returning to atmospheric levels. To avoid this situation, this is why true, deep-sea divers watches are equipped with an HEV.

Thusly, an HEV on a rep is only for decoration and serves no functional purpose, as no rep watch could ever dream of going that low. So, long story short, no need to ever open your watches HEV; make sure the gasket inside is silicone greased and your HEV is securely screwed down before each swim. And don't swim in a watch, unless you've paid the $15 to have it pressure tested. :)

Ciao.

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Just thought of it yesterday why that thing is there...and you post the answer.

Thanks for the post! :thumbsupsmileyanim:

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I think it's pointless for the number of genuines to have HE valves. I would bet that 90% of the watches with valves only get wet when someone washes their hands. My Steelfish has one and it's not like it was something I was looking for when I bought it. It's waterproof to 6000ft.. yes.. 6000. I think that kind of depth rating on a mass production watch is more a gee-whiz factor than anything else.

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gioarmani

Thanks for that, we'll move this to the Knowledge base, after everyone has a chance to read it.

Offshore

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I use mine all the time :rolleyes:

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Yeah, and since SO MANY of these watches are actively dived at depths greater than 200ft, it makes tremendous sense. That's what dive computers are fore.

It's just a bragging feature - "You can't have a REAL dive watch without an HE valve."

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I think it's pointless for the number of genuines to have HE valves. I would bet that 90% of the watches with valves only get wet when someone washes their hands. My Steelfish has one and it's not like it was something I was looking for when I bought it. It's waterproof to 6000ft.. yes.. 6000. I think that kind of depth rating on a mass production watch is more a gee-whiz factor than anything else.

Exactly--it's all about marketing & PR. The almighty image.

A gen sub can go to 1000 ft, but has no HEV, even though you need one after 200 feet? And even though you can't breath regular air w/ nitrogen after 200 ft--not to mention the human head implodes at 600 feet--the wonderful Submariner will still go to 1000 feet, though...

It's all about the sales.

PS: My SMP chrono from Josh tested solid at the AD to 300 feet!

gioarmani

Thanks for that, we'll move this to the Knowledge base, after everyone has a chance to read it.

Offshore

And thank you guys very much. I sincerely appreciate that.

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Exactly--it's all about marketing & PR. The almighty image.

A gen sub can go to 1000 ft, but has no HEV, even though you need one after 200 feet? And even though you can't breath regular air w/ nitrogen after 200 ft--not to mention the human head implodes at 600 feet--the wonderful Submariner will still go to 1000 feet, though...

My Pighead will last at least 2000 feet!

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Most of these heavy duty diver watches never go deeper than a swimming pool. Who really needs the 600m water resistance on the PO, SeaDweller or SuperOcean anyway?

I've hear the real deepsea divers use Suunto diving computers and such.

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It's actually worse than people not using them for deep diving. A HE release valve is worthless no matter how deep you go *in the water*. Its sole purpose is to vent Helium that gets into the case while spending time inside a diving bell or compression chamber filled with Trimix or some other gas mix containing Helium.

No Helium gets into the case when diving in the water at any depth.

Edited by cortopar

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Please do not post this thread in the Knowledge Base offshore because there are a number of incorrect and inaccurate statements here.

I will post the reasons why He escape valves are included in professional deep sea diving watches later because I am currently working and cannot commit the time.

I am a qualified deep sea diving professional currently working on a diving vessel and will post the facts you need when I complete my current working shift.

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Please do not post this thread in the Knowledge Base offshore because there are a number of incorrect and inaccurate statements here.

Possibly a bit too forward and brash for someone with such a low post-count?

You might want to send this to Omega & Rolex if it's wrong (considering they invented the HEV in 1954), because most of this came from my gen's instruction manual...

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Possibly a bit too forward and brash for someone with such a low post-count?

You might want to send this to Omega & Rolex if it's wrong (considering they invented the HEV in 1954), because most of this came from my gen's instruction manual...

As much as we appreciate this insightful information Gio, looking down on someone due to their post-count is very obnoxious. Lets see why he feels the information may be wrong - its a forum afterall.

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Who really needs the 600m water resistance on the PO, SeaDweller or SuperOcean anyway?

Capone says: "Your watch will still be working when you're sleeping with the fishes."

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If you want to know what Omega say, it's this:

What is the function of the helium escape valve on the Seamaster Professional watches?

The helium escape valve was specially developed by Omega for use by professional divers. During deep-sea dives lasting several days, divers operate from diving bells. Prior to surfacing, these bells are filled with a mixture of helium and oxygen. The helium molecules are lighter than air and can therefore penetrate the watch in sufficient quantity to push out the crystal at atmospheric pressure levels. This can be avoided by opening the valve during resurfacing, which allows the helium to escape but prevents water from entering the watch.

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Interesting......

I do quite a bit of sailing, but the only time any water gets on my watch is the spray from the bow or from the bathroom sink. :rolleyes:

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Isn't that an even worse explanation?

Yes, it is, and they invented the damned thing!

Lighter than air? Well, as a matter of fact it is, but that's got nothing to do with it. It's molecule size that matters. :thumbsupsmileyanim:

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Yes, it is, and they invented the damned thing!

Lighter than air? Well, as a matter of fact it is, but that's got nothing to do with it. It's molecule size that matters. :thumbsupsmileyanim:

That's what I thought (although I think you meant to say atom size :) ). Then I had a nagging suspicion that only atoms lighter than air will explode the crystal when the bell is depressurised at sea level. Maybe a physics graduate can work that one out...

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although I think you meant to say atom size :)

No, I definitely meant molecule size. I don't think you'd be wearing a diving watch in the middle of a fission reaction to split the He atoms from the molecules, and if you did, you'd not care about the time. :D

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Thanks for the reply gioarmani and of course you are right I do have a low post count after finding this site just over a month ago.

However, I also have over twenty years experience as a qualified professional (three year offshore training and multiple exams) in the offshore deep sea diving industry - in fact I am currently offshore now on a deep sea diving vessel where we have nine divers currently in saturation diving chambers. The only reason I have the time to write this is because we are unable to dive because of weather.

...and I don't care what Omega or Rolex have said or are saying - the last thing I would do is tell them how to make watches and the last thing they can do is tell me about the deep sea saturation diving industry...especially if the stuff you've posted is from any 'official' source - to be honest some of it is quite laughable but, of course, that's to be expected coz they aren't qualified deep sea saturation diving professionals are they!!!

Anyway, I'll post a proper response to this thread when I have time but please remember we do a 12 hours on and 12 hours off shift system so I might be too tired today.

Just to start tho - divers do not dive for several days - divers live in saturation diving chambers for up to 28 days and transfer to the bell in teams for the duration of the dive only before transferring back to the chambers...and as far as the physics goes - yes I am qualified and experienced with Archimedes, Boyles, Charles', Dalton's, Henry's etc etc - by the way, the term saturation refers to the fact that a divers body is saturated with a helium and oxygen mix of gases under pressure...and so is his watch (and everything else in the chamber)

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No, I definitely meant molecule size. I don't think you'd be wearing a diving watch in the middle of a fission reaction to split the He atoms from the molecules, and if you did, you'd not care about the time. :D

I thought helium does not "naturally" have a tendency to form molecules? Perhaps a chemistry graduate can confirm...

@ themuck. Good post. I look forward to reading the full explanation.

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I thought helium does not "naturally" have a tendency to form molecules? Perhaps a chemistry graduate can confirm...

You're always looking for graduates. I hereby name you Mrs Robinson. :D

Helium is monatomic, yes. It is almost always on its own. This doesn't stop it from being a molecule that comprises of a single atom.

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