The PRISM 2 is an electronically or manually controlled, constant PO2, modular, closed circuit diving system.
As open circuit (SCUBA) divers we rely upon filling our lungs with air from a pressurized gas tank with every inhalation and then exhausting that volume of air into the surrounding water with every exhalation. As we descend deeper the water pressure around us increases and the volume required to fill our lungs increases; in other words, our air supply depletes more quickly the deeper we dive.
A rebreather recycles rather than vents the exhaled breath. The exhaled breath passes into a closed loop, where it is pushed through a chemical absorbent (scrubber) to remove the carbon dioxide, and returns through the other side of the loop for the diver to re-breathe, hence the name “closed circuit rebreather” or CCR.
It’s breathing loop which is a keyed one way assembly consists of a closable mouthpiece assembly with mushroom/check valves either side, which ensure uni-directional flow.
Independent 3rd party testing has also rated the Prism 2 the lowest work of breathing of any mixed gas rebreather available today at 0.94J/L. Click here for actual test reports: ANSTI_Prism2WOB_review.pdf
With the electronics switched on, the secondary also provides a status check for the battery and displays the set point selected for the dive along with other critical information. The electronics vote between the three proprietary galvanic sensors and control the operation of a low wattage solenoid valve on the oxygen supply.
A radial flow scrubber canister is mounted vertically on a backplate attached to the integrated BC, between twin supply cylinders (one each, oxygen and diluent).
The electronics, sensors and batteries are mounted in the electronics head assembly at the top of the scrubber, with supply hoses feeding over the diver’s shoulders into the top of the counterlungs. An analog LED primary display offers a quick reference of unit performance with status and alarm indicators while an independent digital OLED secondary display verifies the unit’s performance.
Dual, front mounted counterlungs provide the diver with a flexible reservoir equivalent to the maximum displacement of the diver’s own lung volume and ensures the lowest possible hydrostatic loading.
These counterlungs are fitted with both automatic and manual gas addition systems and a variable volume control valve (used upon ascent to vent excess expanding gas volume or to purge the loop). Diluent addition is automatically achieved as hydrostatic pressure increases and the counter lung collapses against the valve
|Length||21in (53.3 cm)|
|Width||17 in (43.2 cm)|
|Depth||9 in (22.9 cm)|
|weight||approx. 47 lbs (fully charged) with 19 cuft tanks|
|Scrubber Flow Design||Radial|
|alternate inflator bail out||yes (Hollis 310)|
|counter lungs||Over the shoulder|
|PO2 set points||adjustable (0.7, 1.0, 1.2, 1.3, 1.4)|
|O2 sensors||3 galvanic|
|Sensor life||12 months in air or 100 hours dive time|
|Heads Down Display||Yes, battery powered sequential LED|
|Analog PO2 display (Secondary)||Yes, powered by O 2 sensors|
|battery type||9 volt|
|battery life||40 hrs|
|automatic setpoint switch||Yes @ 20 ft (6.1m) on Descending, 18 ft (5.5 m) on ascent|
|integrated weight system||yes|
|Diluent bottle sizes compatible||13’s, 19’s; 30’s (cuft)
1.9, 2.7; 4.4(liters)
|O2 bottle sizes compatible||13’s, 19’s; 30’s(cuft)
1.9, 2.7; 4.4(liters)
|scrubber duration||245 min @(60 fsw, 40F, 1.3L/min CO 2,0.5%CO 2 SEV)|