Hyperbaric Chamber Question.

[Superlyte27]

I know when you get to wear a hat you have already learned some physics that apply to diving.
It is obvious to me some people are getting into a hat and do not know what they are wearing
and why they are wearing it! (or they just have a cool name)
DOES SUCK SOME FACE PLATE MAKE SENSE?
Nice explaination Diverdoug!
See you topside! John

Well, you might be right about that, since I dove a Mark V as a novelty one time. I don't understand the physics behind that hat because I was never intended to use it. In case that was directed at me. Oh, and if it was, SUCK IT!

But, as far as my hats, and the hats i've dove for a living. I absolutely understand what's happening with them. They are not sealed air tight units. They are in essence, a regulator and a skull cap for protection. The only difference between my hat and a Band Mask is the shell.

 

[Thalassamania]

I think someone might have been having you on about the superlyte diver's eyes. A crushed orbit can extrude the globe of the eye, but I don't think that an eye can be evulsed from the orbit by exposing the whole cranium to a very low pressure (but they could bulge if the suit was crushing the lower body and increasing the venous pressure - pushing up into the helmet.) I would think the dam on the superlyte would rupture before there was that much pressure differential. I am not an opthalmologist though, so I may be wrong. It does make for a unforgetable mental image though!

I don't know about this one either. There is no air pressure behind the eyeball to "push" it out, but there is hydraulic pressure being transmitted through the body fluids that is unbalanced by the lesser pressure in the hat. What does that mean in terms of one's eyes bugging out? I don't know.

 

[diverdoug1]

Hey superlyte, I think a lot of the possible confusion about this whole subject is that a Mark V helmet has a "hard connection to a suit with very little stretch. If you were to pump a lot of pressure into a Mark V while attached to the suit, to suit would stay at very near the original volume (assuming you compensate for glove seal) untill it burst (big bang). I have used KMB-28 and 17 and they would "burp" pressure at the seal inj this situation (it is a closed system but not closed to the point of failure). I realize I am a little unclear here, I think that if we were all face to face, we would all be in agreement in 30 seconds, sometimes it is hard to talk without drawing or using your hands. Also , where did you get to dive the Mark V? I did it twice in Tarpon Springs Florida, and it gave me a real appreciation for advances in technology! I know there a lot of guys on the board who are into diving vintage open circuit, but I'll bet that there are not many that are into diving vintage commercial gear!!!!!! If there are, I bet you like to pay the ladies with the black leather and whips!

 

[Superlyte27]

Hey superlyte, I think a lot of the possible confusion about this whole subject is that a Mark V helmet has a "hard connection to a suit with very little stretch. If you were to pump a lot of pressure into a Mark V while attached to the suit, to suit would stay at very near the original volume untill it burst (big bang). I have used KMB-28 and 17 and they would "burp" pressure at the seal (it is a closed system but not closed to the point of failure). I realize I am a little unclear here, I think that if we were all face to face, we would all be in agreement in 30 seconds, sometimes it is hard to talk without drawing or using your hands.

I agree. I have a friend who spent a decade in a Mark V. I'm meeting him for lunch on Tuesday. I'm going to get the full scoop.

I promise, if i'm a blooming idiot. I'll post it here.

 

[diverdoug1]

I agree. I have a friend who spent a decade in a Mark V. I'm meeting him for lunch on Tuesday. I'm going to get the full scoop.

I promise, if i'm a blooming idiot. I'll post it here.

If he spent a decade in the Mark V, you might have to chew his food for him!

Just kidding, respecting my elders is getting very easy as I become an
"elder" myself.

 

[Superlyte27]

Lol, he is kinda old.

 

[orm]

I read the op's post and the last page.... concerning helmets and eyes, I'm sure they all link in faultlessly.

I spent a bit of time in a chamber once... as far as I remember the door opened on a screw system and opened inwards. I may be wrong, it was a fair few years ago.

Plus, the maximum 'depth' it was capable of was about 16m. Not really body exploding stuff, although I wouldn't want to try it, you'd probably get a few ruptures.

Again, this may have been said, if so... sorry and carry on with the helmet/eye combo.

 

[Aquatic Eagle]

Plus, the maximum 'depth' it was capable of was about 16m. Not really body exploding stuff, although I wouldn't want to try it, you'd probably get a few ruptures.

I don't know much about recompression chambers but it seems that 16m is very shallow for one. It doesn't sound like much of a chamber.

 

[diverdoug1]

Over 90% of the chamber work I do is with a spacious chamber rated for less than + 3 atm. The remainder is research that uses a diving bell that we have placed in our lab (my assistants like to call it the "Big MF"). Here is what I think would happen in a WORST CASE SCENARIO with a therapeutic recompression vessel. We are at slightly over 3 atm. of pressure with patient and chamber technician in the chamber, a catastrophic failure of the chamber occurs, resulting in an instantaneous decompression. Both patient and attendant are unresponsive, with blood coming from the ears, nose and mouth. We could see severe barotrauma to the ears / lungs / and sinuses, aspiration pneumonitis as well as negative pressure pulmonary edema developing in living subjects over the next few hours/days. Very possible AGE / DCI, maybe fat emboli due to foaming in the blood, but no exploding body parts. We would treat survivors with ventilatory and hemodynamic support, IV steroids, and recompression therapy when appropriate. Shrapnel would also be a concern for people near the chamber when it explodes, and divers will be posting about it on Scubaboard for the next 20+ years.

 

[orm]

I don't know much about recompression chambers but it seems that 16m is very shallow for one. It doesn't sound like much of a chamber.

When you're breathing 100% O2, 16m is deep enough