Portable Hyperbaric Chambers

[Thalassamania]

I guess I'm old school, but if I want a chamber I want a minimum four-place, dual lock, metal chamber equipped with a BIBS.

 

[Wayan]

Exactly John,

My query was trying to elucidate what more scrutiny is there in the HYPERLITE to make it safer over an above other certified hyperbaric units. The impression I go from the statement as opposed to metal and aluminium chambers that have been around for years. Standards are written so as that the unit has benchmarks it needs to achieve to be able to certified in this case PVHO as well as ASME VIII and other stanadrds as appropriate like NFPA etc.

The standard for the hyperlite will be different as it has more risks flexible housing, transportable, etc etc etc. Just because there are more hoops to jump through to get the unit certified does not make it safer.

Yes for short hops I can see a use for the unit. I would hate to have to do a USN TT6 in the thing) (defalating inside a chamber yes well a nice large should be simple enoughbut in a smaller one well I would imagine difficult. In remote locations, put in a duoplace unit maybe capable of seating say 4 - 6 would more comfortable, then get staff trained etc. Still need Medical Support, nothing negates that as recompression treatment is a Dr's prescribed treatment. I know of lots of remote locations that operate the use units with local staff have a international company come and service the unit every 12 months do the safety audit inspection, re-evaluation staff procedures and education and this company can provide 24/7 medical support for the unit.

Personally I like the DART with the ARTEL pack.

All can be extremely claustrophobic if you do not like being in a cocoon.

 

[Wayan]

Hi John.


Now not wishing to be rude here, but to compare those costs against a metal shell that in 20 years would only have you replaced the 0-rings every 5 years and the viewports every 20 years at a cost of what? $200 each.
Middlebrook

Hi Ian think you might be missing a zero on your viewports at 200 each if not pm me the name of your supplier please

 

[hyperbaricjosh]

Remember all, the Hyperlite is and Emergency Evacuation Hyperbaric Chamber, those Duocom Drager Chamber posted by Iain will do the job and yes they will last forever, however I want to point out that the skill required to operate such chamber is much greater than to operate a hyperlite. On another note, the weight for those unit is 529 lbs (240 kg) emptied and without the required bottles to do a complete TT6. I can tell you that if you want to do a full USN TT6 with extentions you will require 2 K size bottle of air and 2 K size bottle of O2 and in order to carry those bottles you will need an undercarriage. The chamber comes with 2 mating/emergency bottles with a capacity of 77 scuft each strickly used for doing a TUP (transfer under pressure) or for emergencies. Now the weight as gone up to about 1200 lbs not including your patient and attendant (average weight of a person 190 lbs) so you see your transportable metal now needs a forklift to be carried around. Both chamber has their purpose. The price for a Duocom drager chamber goes around $160 000 USD I have used those chamber in the Arctic and treated a diver back in the 80's we ahd to get it up there by Hercules aircraft. So, everybody will have their arguments on what to use and what is best, but I can tell you that you that you will get more bang for your buck and an exceptionnally well design and fabricated Hyperbaric stretcher with the Hyperlite. Josh Boisvert

 

[iain/hsm]

(EDIT) Personally I like the DART with the ARTEL pack.
All can be extremely claustrophobic if you do not like being in a cocoon.

Wayan.
I tend to agree here, some very good points. However I think the various worldwide pressure vessel codes and standards should be examined in detail in the light of this specific application.

IMHO In most cases, you will find that the detail code found for hyperbaric vessels does not adequately cover design standards for the requirement of a decompression chamber at sea.

It should also be understood by both customers and those responsible for the use and treatment of divers in chambers on vessels “in at sea conditions” that these medical hyperbaric chamber compliance codes and standards such as in the medical device directive NFPA etc may mean that the design is acceptable, However it DOES NOT follow that the design is safe.

Safety should be the designer’s responsibility, and with both the ASME or PED5500 and the various European codes there are two very different approaches to chamber safety design.

First principle is safety design by analysis. In the US this would be under ASME 8 division 2, whereby finite analysis would be used to calculate the vessel stress in order to keep it within the allowable pressure/stress levels.

The other option would be design by rule or by a written code such as ASME 8 Division 1 or in our case in Europe PED5500, CODAO or AD Merkblatter, using design graphs and calculated basic shell construction from charts to keep the pressure stress within the design code.

One example I can give you, using your comment of your preference for that DART chamber is if you look closely you will see that the dished end is made up from a number of welded parts. This is called a crown and petal end. You will only see this type of construction in low cost construction, another example is a similar styled chamber made in Czechoslovakia.

A good quality designed ASME or BS5500 chamber will always offer a single piece dished end due to the massive addition to safety a single plate end piece construction offers. Iain Middlebrook

 

[iain/hsm]

Hi Ian think you might be missing a zero on your viewports at 200 each if not pm me the name of your supplier please

Wayan.
You are quite correct I had no right quoting our engineering prices, also I did not correctly work out the exchange rate The $200 quoted should have been $225. It would have been easier just to say £150.GBP. This however is the price we charge for a standard 170mm by 25mm thick viewport with PVHO-1 certification used only on our chambers and again 10 years later only when we service them.

Now I am not responsible what others charge or if you purchase yours from a medical or diving supplier. In each case the seller will add a mark up to his cost. Now some may think this 10 fold, increase of profit medical dealers get making it a $2000 viewport is a bit high but they get paid more than the engineers that designed and built the chambers in the first place and on that I cannot possibly comment.

The poor photo enclosed is of my desk at work today with some varous ports showing some of the different styles sizes and pressures from 165FSW to 825FSW depth ratings. Due to the low cost you might think customers would replace every 5 years along with the hydro? No chance!!! LOL

As well as being a manufacturer I am also a certified PVHO inspector so I now have to look forward to a PVHO-1 20 year viewport life. So much for my get rich quick idea.

Of the work done this month, I shall be retired by the time they are replaced, So I suppose I have some small mercy to be grateful for. LOL Iain Middlebrook

 

[iain/hsm]

those Duocom Drager Chamber posted by Iain will do the job and yes they will last forever, however I want to point out that the skill required to operate such chamber is much greater than to operate a hyperlite.

The price for a Duocom drager chamber goes around $160 000 EDIT . Josh Boisvert

Josh.
Thanks for the kind words. Although I don’t dare talk badly about chambers I have to take issue on your “lasting forever” comment. 30 odd years ago I could climb through a 24inch manway no bother, on some larger saturation chambers with the 18 “hat” locks those too. OK so now a days I work on the basis that the stretcher provided is for my own personal use, but I do still have some active life left in me. LOL

You will note that the first photo I posted is not strictly a transportable chamber you can see the heavy bolt down section and anti vibration mounts. For the OP’s use I would have the chamber bolted down below deck and forget all this transport under pressure nonsense.

I did think we had moved on from those heady days of dangling divers on a string under a six ton flying fan blade and other such sea stunts of “dipping” one man navy chambers in the sea to cool it down while attempting a port call at the “Ziggy” navy base Cyprus while achieving a table 6.

The answer to these and other non engineering questions is IMHO Valium, lots of Valium or any other diazepam derivative.

For the practical solution as with all these small chambers is that by the time you get back to port or wait for the rescue the treatment is over, 4-5 hours and your done. Treatment finished diver on deck. Then if required you can call in the transport, or stick him on a local bus if you have too, but treatment is over (at least for the day).

Also not easy to see in that 1st photo that you can smash the diver down to 165FSW 50MSW for a serious gas embolism but these newer chambers use a 50/50 Heliox mixture on BIBS with the Comex 30MSW treatment table as well as the pure oxygen Table 6. The BIBS are modified for depth by incorporating a negatively biased tracking regulator to overcome the risk of inbuilt BIBS dump. Can be used with Scott Pressure VAK II or the any other make. Same as used in sat chambers to 300MSW. So at worst the maximum depth is only 30MSW 100FSW and the time for a comex treatment. five hours,

Driving a chamber is no more difficult than mixing gas in filling a scuba cylinder, granted the panels in the 1st photo may look a bit daunting but there are other cleaner simpler laid out design options around to give a more “medical” clean feel, if that is what is required.

As to cost I can assure you that from the engineering standpoint they are sold at the same price as a small car around $40-50K so I must ask who the heck paid $160,000?
That’s three times cost!!!. No wonder you don’t see many on liveaboard’s.

Even on the largest pleasure craft we have put these chambers onto, I can testify that in the main the Jacuzzi was dearer. Iain Middlebrook.

 

[John_Selby]

1. I am not against metal chambers, they have their place, but do not happen to be foldable or lightweight as is the Hyperlite. When boxed, two people can move the cubic Pelican case around with ease and it has wheels too! I see great benefits in a two person plus chamber, and that is what I would like to be building one, but with size, you lose portability and require considerably more gases.
2. We do not believe in mono 5 bar chambers. They can become plastic 'coffins' but not a 60 fsw (18 msw) chamber where you can always take the patient out in critical circumstances, and probably without causing the patient any further complications.
3. Our windows are 20" (500mm) in diameter at both ends of the unit to reduce the claustrophobic affect.
4. I visited NOAA HQ in Seattle last year and saw their Draeger Duocom looking pristine and shiny along one wall. They said that they don't use it anymore, not since they have Hyperlites!
5. We carried out 10,000 cycles in our recent test program on the new model. That gives us 4,000 uses per tube or ten years, whichever comes first. At ten years we have to replace the tube only, everything else is still good for another ten years, subject to window inspection meeting the requirements of ASME PVHO-2.

 

[JonKranhouse]

Sometimes, good ideas take 80+ years to catch on!

The above image is from K.K. Jain's renowned Textbook Of Hyperbaric Medicine. (BTW - it's worth reading the user-review by "Doulos" on Amazon's webpage for this book).

The book's forward quotes Edward Teller, Director Emeritus Lawrence Livermore National Laboratories and the lead scientist who developed the hydrogen bomb. (In a personal communication to Jain, Dr. Teller assures the empirical physics of HBO, and is convinced that HBO enabled him to recover from a serious stroke. Dr. Teller is also convinced that his daily HBO regimen has enabled him to continue working full time at 93 years of age). To this day, the UHMS denies HBOT 1.5 is efficacious for TBI, stroke and ANY other neurological maladies - except for purging carbon monoxide from the body. I digress...

Here's the US Navy's 1999 evaluation of the Hyperlite as an "Emergency Evacuation Hyperbaric Stretcher (EEHS), which ends with this conclusion:
"With foresight [i.e. staging, transport and training of personnel], many lives could be saved and disabling permanent injuries could be prevented.

You can download the 2003 PDF of the US Navy's OPERATION AND MAINTENANCE MANUAL FOR THE EMERGENCY EVACUATION HYPERBARIC STRETCHER (EEHS) -- from The Office of the Director of Ocean Engineering, Supervisor of Salvage and Diving (SUPSALV)

 

[fakeplant]

Wow, I don't know about you JonKranhouse, but I am nervous of any technology endorsed at the turn of the 20th century. I mean, some other things that accompany is an electroshock belt to help you lose weight, an opium snake oil, to name a few. I am not saying you have a valid observation, but for me, that works against the chamber But that's just my two sense. With that being said, my Mom used those chambers to help treat her limes disease. In fact, I have read that it is increasingly being used to "treat" children with Autism. I am not exactly sure how the chamber works to help with Autism, but a lot of the newer alternative medicine journals are talking about it.