Kent Cedola’s Inspiration Rebreather exposed

On a recent dive trip aboard the Nautilus Explorer up in balmy BC Canada I had the chance to dive with Kent Cedola. Kent dives an AP Valves Inspiration E-CCR or Electronic Closed Circuit Rebreather. This is the most popular of all the CCR’s currently on the market. The manufacturer will not reveal how many units have been sold, but I have heard estimates of between 4000 and 6000 units. Kent agreed to let me shoot some pics while he serviced his RB at the end of a days diving, notice the winter jacket Kent is wearing, is was about 40 deg out on the fantail of the Nautilus that evening….brrr.

Here is the rig, back from the days diving. The Inspiration sports dual over the shoulder counterlungs, which also serve as water traps. Notice the T-connectors between the breathing hose and CL’s, the right side (divers left) also houses the ADV (Auto diluent Add Valve) which is an option on the Inspiration. The mouthpiece rotates while the hoses are held stationary to open and close the DSV or dive surface valve/mouthpiece. The RB comes with an “Air 2” type inflator with access to the diluent O/C, it also controls inflation of the BC and has an integrated over pressure relief valve, those clever Brits. Notice the BC hose dropping down on the far right with the “air 2” on the end. A Cochran dive computer and compass hang off one of the handsets. There is a buzzer that activates with low PPo2, high PPo2, battery or cell failure, it is aimed at the divers head on the divers left, you can see it in the pic just to the right of the ADV, it’s a small black cylinder. At the bottom of the right (divers left) counterlung see the manual diluent add button (blue and white button). The manual oxygen add is on the exhale CL near the bottom. (not visible in the pic). There is also an adjustable pull dump valve that will relieve pressure in the counterlungs on the divers right about chest high.

A 19 cf pony used for bailout hangs off of the right side of the shell, see mounting below.

Here is diver ingenuity, mounting a small knife on the back of one of the handsets.

With the cover removed, diluent on divers left, top of pic, oxygen on right. The center canister contains the scrubber as well as the electronics, solenoid, battery compartment and o2 sensors. Kent uses a g-snap pony bracket to mount his bailout bottle. Nice shot of my shoe also.

Bottom of unit showing cylinder valves that protrude from the sides of the housing. DIN valves on both sides.

With the cylinders removed, you can see the exhale hose meeting a plastic line that feeds into the bottom of the scrubber canister, that is held in place by a nylon and Velcro strap.

Top of canister, two connectors for the handsets, one for the oxygen line that feeds the solenoid another for the buzzer and in the center, the inhale breathing hose. AP valves uses really nice threaded connectors for their hoses making breakdown and rinsing of hoses simple and quick.

The bottom half of the shell, minus the cylinders and canister, note the manifold running across the top of the shell on the right side of the pic. It splits the feed of both the oxygen and dil, one at each end, neat. Cylinders are held in place by nylon and Velcro too.

The canister freed of its mounting, ready for a scrubber change.

Kent, wishing it was warmer, but you can tell he is from the NorthWest, no one else in the world wears sandals, with socks.

Top of the inside of the scrubber canister, 3 sensors positioned around the tube leading to the divers inhale hose. Lots of moisture collects here, remember the sodalime makes heat and moisture during its reaction with the CO2 the diver produces. One potential problem is getting moisture on the faces of the sensors so that the oxygen cannot reach the galvanic material. The sensors have hydrophobic membranes which makes sure they are not hurt by the moisture, but moisture will stop them from reading properly. The black compartment to the bottom left of the pic is the battery compartment. The oxygen injector is in here too.

Kent uses a small air gun hooked to his diluent bottle to gently blow the moisture from the underside of the canister. Nice dry clean air, you wouldn’t want to use a shop air compressor for this job.

Scrubber canister. Center black wingnut holds the top on. The four studs are where the 4 SS hand nuts screw the lid down. See the hand nuts at the very top right side of the picture.

Battery compartment uncovered, one battery for each handset, either one able to control the RB’s injection. The batteries are 6 volt lithium and will last about 35 hours if powering the master handset and 70 if powering the slave.

Scrubber cartridge coming out of the canister, notice the springs on the bottom ensuring the scrubber material is kept tight.

Coffee filter holding all the small granules of sodalime in place.

The guts of the scrubber can.

A rather poor pic of the handsets. Menu driven, independent controllers of the monitoring and injection system. The first one turned on act as the Master and the next one will act as the slave, if the master is turned off the slave will take over in one second.

Kent taking a hit of pure O2, continuing his off gassing.

A few more facts. The Inspiration is a 100 meter capable E-CCR and can be used with air, heliox or trimix as diluent. The cylinder capacities are 19 CF. The unit at the surface is used at a ppo2 set point of .7. After descent the diver manually selects a higher setpoint, usually 1.3. The handsets do not provide any decompression information, only set point, sensor readings and menu options. The manufactures recommendation for scrubber usage is 3 hours, this is figured at a CO2 production of 1.6 lpm, that’s a lot of CO2, remembering that CO2 production approximately follows oxygen consumption. Its not recommended to push this, a CO2 headache is a real pain.

Thanks to Kent Cedola for allowing me to take pictures and pick his brain. The Inspiration looks like a nicely engineered unit that should hold up for years of diving. As always, training is required before using any scuba equipment and especially a rebreather. Ignorance will kill you, seek out a competent instructor for training. Dive Safe.