hyperbaric chamber

[Jeff Allen]

do hyperbaric chambers have to be round? can they be rectangle?

 

[WillHartNZ]

The one I took a ride in was rectangular. Basically a room sitting within a room.

I would assume that cylindrical chambers would be cheaper due to the distribution of force that that form provides. Not an engineer but just an educated guess based on high school physics and design.

 

[broncobowsher]

Rectangles tend to deform into circles when you put pressure into them. The walls would have to be really strong to not deform. Pressure vessels from scuba tanks to the disposable propane tank are round for a reason. It would take a lot more engineering to make a pressure vessel with flat sides. Although a flat walled room can be put into a round container easy enough.

 

[Akimbo]

They can be any shape you want, but the farther you get from a sphere the less efficient they are at distributing forces. In practice, the only flat parts of a hyperbaric chamber you will see are the viewports and occasionally blank flange faces on saturation diving systems. The vast majority of pressure vessels for all purposes are cylindrical with semi-elliptical heads to spherical ends including propane and Scuba tanks.

I was a principal in a manufacturing company that made chambers for the commercial diving industry with ASME/PVHO and DNV certifications. Here is a drawing of a typical viewport:

This port is rated for 100M/328' with an 200mm/8" minor diameter.​

This is a typical portable 54" double-lock chamber used extensively in the commercial diving industry for surface-supplied operations. You will often see them in smaller HBOT markets that also treat DCS outside the US.

 

[АлександрД]

even this shape:

Dräger- Druckanzug zur Behandlung von Dekompressionskrankheiten, 1915. Decompressionsuit from 1915 to cure people who are suffering from decompression illnesses. The image is out of the book: "Sphären III - Schäume", by Peter Sloterdijk, Suhrkamp Verlag, Frankfurt am Main, 2004. ISBN 3-518-41466-6.

 

[WillHartNZ]

This is the one I was referring too. Given that it was in a hospital I would guess construction methods weren’t more deciding than functionality.

 

[txgoose]

This is the one I was referring too. Given that it was in a hospital I would guess construction methods weren’t more deciding than functionality.
View attachment 465006

Also note that it is surrounded by a cage of I beams. It has significantly more reinforcement than a plate cylinder needs. As you said, flat is doable but at a cost.

 

[mmerriman]

Hyperbaric Technologies Gamow Bag Hyperbaric Chamber, Civilian Model

 

[Akimbo]

This is the one I was referring too. Given that it was in a hospital I would guess construction methods weren’t more deciding than functionality.
View attachment 465006

Do you know the maximum operating pressure of that chamber. I suspect it is lower than is required for conventional DCS treatment. HBOT (HyperBaric Oxygen Treatment) is mostly in the 20-30' depth range while DCS treatments call for 60-225'.

In any case, operating a chamber that is not certified by a locally recognised agency is a huge liability if it explodes and someone is injured. That puts chambers of all kinds out of reach for DIYers. Don't forget that pressure vessel failures are bombs.

 

[tbone1004]

the square ones are likely cheaper to manufacture since there is no metal bending involved, but I imagine are usually rated for a lot less pressure than ones used for recompression therapy. I.e. if you're treating CO, wound care, etc. you don't need a chamber that can go to 10ata, one that is rated for 4-5 is more than enough and that can handle a lot of diving stuff, but may or may not.

@Akimbo the pressure of the bag that @mmerriman linked to is only 2psi, so about 4.5ft....