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Hi Barrie,
On Wed, 14 Dec 1994 08:31:59 -0800 bmk wrote:
>
> >My understanding is that most of the rebreathers use triple redundant O2
> >sensors. If these are the same type as used in O2 meters (E.G: miniox), then
> >this could become a significant cost. Here in Oz, a Miniox sensor retails at
> >around $A200. Apparently they last a year or so if used frequently. Hence you
> >may be looking at upwards of $A600 / year in oxygen sensors alone!
>
> The documentation for the Biomarine Seapack 1000 states that it uses 3
> sensors which have a life span of 6 months. Hence your cost might be
> $A1200/Year!
I don't think life is *quite* that bad. At a dive show in the UK in '94
I reported :
- Vandagraph Ltd displayed a neat, splash-proof oxygen analyser selling
at 195 pounds UK ($US 300), in a rugged carry case. The sensor lifetime of 4
years is expected in air.
A trimix analyser is being developed, but I have no idea how this might
work. Try giving a call if you are interested Tel. 0535-634900,
fax 0535-635582. (For international calls, remove the 1st zero and replace
with
44)
Of the $US 300 total cost, I think the sensor was in the order of
$60-$80 replacement cost. It had a guaranteed lifetime of 2 years, but was
usually expected to last about 4 years with continual exposure to air.
The costs of scrubber, disinfectant & other running expenses...oxygen,
helium etc I couldn't guess right now...but I'll have a better idea after the
Cis-Lunar course in early January.
As an aside, I got two quite different opinions regarding the mix to be
used in a fully closed-circuit rebreather during disscusions @ the Diving
Officers Conference earlier this month. When talking to Oceanic about their
'Phibian' rebreather I asked about the conversion from nitrox to other mixed
gasses & without really thinking spoke of using trimix as the diluent. Oceanic
quickly replied that the diluent was going to be a "breathable heliox" & that
there was no point in putting nitrogen into the diluent ...as you were not
trying to save costs on a small volume of gas that was recycled. A quite
different view was put by Rob Palmer & Dorset Diving. They said that you
*would* want to use Trimix as the diluent because this would result in
*significantly* shorter decompression times.
As I'm not yet diving on either gas mix, I couldn't comment sensibly.
Has anyone else got a comment ? How do deco times work out using open circuit
trimix or heliox (never mind the cost...) for a comparable dive ? If trimix
does work out shorter deco times, would the same conclusions be true for a
constant ppO2 closed-circuit dive ? (What I'm really asking is for someone with
a copy of 'Pro-plan', 'Abyss', 'Decom', 'Dr X' etc to run a few trial dives &
see what answers it gives.
Anyone got any spare time whilst the rubbish tv progammes are on 'the
box' over Xmas ??
>
>
>
>
Regards, Steve M.
**************************************************************************
* * *
* Dr. S. G. Millard, * E-Mail : ec96@li*.ac*.uk* *
* Senior Lecturer, * *
* Department of Civil Engineering * Tel : 051 794 5224 (UK) *
* University of Liverpool, * 44 51 794 5224 *
* PO Box 147, * (International) *
* Liverpool L69 3BX, * *
* UK. * Fax : 051 794 5218 (UK) *
* * 44 51 794 5218 *
* * (International) *
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