What causes the depth limit on a KISS Sport Rebreather

[DiveLvr]

I read the mfr suggested depth limit for the KISS Sport is 130 ft. I also read of people that modify the unit to be able to go down deeper. I am not interested in actually making any such modification but I would like to know what causes the depth limit.

Thanks,

DiveLvr

[cloudflint]

The oxygen is injected into the loop at a constant rate that does not change with depth (Since obviously your oxygen consumption doesn't either). This is done by basically having a regulator set to some intermediate pressure say 5 bar and then letting oxygen "leak" into the loop through a tiny little hole. If in this instance your intermediate pressure is 5 bar and you go to 130 feet you have now reached 5 bars of ambient pressure and the flow of oxygen will stop!

If you wanted to go deeper with this system you could half the size of the hole the oxygen leaks through and double the intermediate pressure of the reg, this would mean the flow wouldn't stop till you reached 90m!

[DiveLvr]

Thanks cloud

[wedivebc]

actually the ip limitation doe not come into effect until about 260 ft. The depth issue with the sport kiss has more to do with lack of water tolerance and poor scrubber design. There isn't much one can do about that. I have had one down to 240 but I wouldn't want to do that again.