Oxygen Control
Oxygen control on the KISS rebreather is best described as manually controlled with a safeguard. This isn't as complicated as it sounds. The CCR comes equipped with a metering orifice that slowly feeds oxygen into the loop at a rate slightly below the average metabolic rate of the diver. This
is usually set to about .7 litres per minute. What this means is that if the diver is consuming .7 litres of oxygen per minute, they don't have to do anything. If they are consuming more, then they will need to add oxygen. This is done by operating a simple thumb-operated valve.
It is important to remember that the metering orifice is not a set point controller. It will always add the same amount of
oxygen regardless of the diver's workload. It is essential that the diver monitor the O2 displays.
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PO2 Displays
The KISS rebreather comes equipped with three independent, backlit PO2 displays. Each display has its own housing, battery and sensor, making the system completely redundant. The batteries are user changeable. Each display can be replaced independently and spares are easily
affordable.
It is important to note that they are displays only. There are no alarms, bells, whistles or anything to alert the diver should the PO2 move out of the recommended area. It is essential that the diver monitor the displays every few minutes and adjust the oxygen if necessary.
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Scrubber
The scrubber has a basic axial flow design which is resistant to channeling, but has a higher breathing resistance than radial flow designs. Channeling is when the gas bypasses the scrubber bed. The Classic Kiss holds approximately 6 pounds of 4-8 Sofnolime. It is recommended that the scrubber be
changed after three dives or three hours, whichever is less. |
Counterlungs
The Classic Kiss uses 2 back-mounted counterlungs (split counterlung) that are available in 3 sizes: two, four and six litre capacities. This enables divers to closely match their own lung capacity, which permits easier control of buoyancy.
Back-mounted counterlungs leave the chest area
clear and reduce the number of hoses and fittings compared to the over the shoulder counterlungs found on other CCR designs. These counterlungs are subject to changes in breathing resistance as the diver changes position in the water. If you roll on your back you can expect a case of chipmunk cheeks. Nothing is perfect.
Spare counterlungs can be purchased at minimal cost.
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DSV (Mouthpiece)
The KISS DSV can go from closed circuit to open circuit mode by twisting the knob at the bottom. It is an easy 2 finger motion. This bailout mouthpiece can provide an alternate method of adding diluent gas or even an alternative diluent depending on the connection. Also, it is an easy way to
purge the rebreather for verifying the sensor readings. Most importantly, however, it can prevent panic in the case of a malfunction in the CCR by allowing a fast, simple way of getting your next breath. |
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ADV (Automatic Diluent Valve)
This valve adds diluent when the loop volume is reduced by either descending or breathing down the volume of oxygen. The diver simply inhales hard to trigger the valve. Suddenly finding yourself unable to get a breath during a rapid descent could be a panic inducing situation.
This valve will eliminate that.
The ADV must be set up tight enough that it doesn't add diluent without the diver being aware. It also needs to add enough gas so that a reasonable descent rate can be maintained.
Any time the ADV triggers, you need to check your PO2. You have either descended and compressed the gas in the loop or you have consumed enough oxygen to reduce the PO2
significantly. This may also have caused you to lose buoyancy and descend.
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Tanks
13 cu.ft. tanks are recommended. As the limiting factor on the CCR is the 3 hour scrubber, this provides plenty of gas. A 13 cu.ft. oxygen tank will provide 5 hours of oxygen at a consumption rate of 1 liter per minute. A 13 cu.ft. diluent tank will provide enough gas for an experienced rebreather diver
to do two, 1 hour long dives to 150 ft.
If you carry more gas than this, and you should, it should be in the form of emergency bailout, open circuit gas in separate tanks. A larger diluent tank is not an adequate bailout gas supply. Carefully analyze the failure paths on your gas supply and don?t put all your eggs (gas) in one basket (tank).
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