Warning: Cooper hoses - dangerous failure mechanism

Hi Mr_Pyro,

Save yourself the expense as these have been tried. They are all too stiff. Based on some empirical testing, many of the promising pruducts in the industrial catalogs are just too stiff. They don't seem that way until your mouth is attached. Personally, several have been tried from Alfagomma, a very similar line.

The Cooper Hose is an excellent model, superior to rubber in offering a multi-layer hose more resistant to puncture. Their only failing does seem to be in transfering the mechanical load at the cuffs. This is hard to solve since the trick is to transfer the load from the mouthpiece or the rebreather to the spiral without having that stress go only through the cuff. Doing something fancy with the spiral is out since it complicates manufacture. They've opted for the fabric to act as a load transfer mechanism to reinforce the rubber. Sadly, it's cycle life isn't outstanding.

The winning elements to the cooper hoses is the combination of very soft rubber. The things are very floppy and this is what is needed. The metal spiral is the main structural component and maintains great flexibility. The final element is the fabric, giving the hose puncture resistance and binding the steel and silicone together. The only missing element is load transfer at the cuff. Something is needed to distribute the forces acting at this point. One could imagine a harder plactic shell at the cuffs that adheres to the silicone rubber to seal the thing yet strong enough to transfer the stress from the cuffs to the wire. In this fashion, the rubber is not working, just along for the ride.

In conclusion, you would want to do exactly what the Cooper hose is doing and with the added FEA or widget to manage the stress transferred from the coupling to the hose.

So what we need is a brand new design of hose.

Why? I can only imagine ccrb moved to these hoses out of WOB concerns. I wonder how much difference smooth bore hoses really make in the grand scheme of things.

Personally Im all for improvements/innovation, but it has to be said sometimes leading edge can be bleeding edge.

Why? I can only imagine ccrb moved to these hoses out of WOB concerns. I wonder how much difference smooth bore hoses really make in the grand scheme of things.

Personally Im all for improvements/innovation, but it has to be said sometimes leading edge can be bleeding edge.

The Cooper hoses are an excellent starting point, this would constitute a very minor improvement.

All that would be needed is for the wire to terminate in the cuff. This would provide the transfer of load with the hose clamp cinched down on it.

This could be achieved either by straightening the last bit of the wire and casting it within the cuff portion. An alternative method would be to weld a flat tab that would provide a bit more surface area to transfer the load in the cuff.

There is nothing innovative about Cooper hoses. They have been used for many years.

While I agree that it is a good idea to be aware of this failure point, I still believe the benefit of the tough hose design and smooth inner bore (more for cleanliness issues than WOB) outweigh the downside. I've had regular hoses fail and leak on a few occasions...never had a problem with the Coopers (yet ).

Aloha,
Charlie

but they all migrated ... pass my sphincter