K. Diluent gas addition block with female QC6

MX Rebreather - Diluent gas addition block with female QC6

The diluent block is similar to the O2 injection block in that it is completely manual and requires the diver to press the button, again with either hand, to add diluent to the loop. The difference here is it stowed on the right side, closest to the diver inhalation breathing hose, and therefore if a diluent flush is needed, it can be done quickly and effectively and reach the divers mouthpiece without having to mix in the canister first. Diluent flushes are thought of as a safety procedure if you get an O2 spike while diving. Small amounts of diluent can easily be controlled and added to the loop.

The primary inlet to the diluent Injection block is a LP hose that is fed from the right primary post first stage. It is connected to an isolator shutoff (see section “P”) before entering the injection block, allowing it to be shutoff or isolated if necessary. This may be important in a situation in which the injector is self inflating and the diver wants to prevent this without having to shut down the right post and donate-able OC long hose.

The diluent injector block also has a secondary inlet which is a wet pluggable female QC6. As discussed earlier, the advantage of this fitting is that if nothing is plugged in it will not allow water to penetrate the block. However the diver can use this side as a “backup injector” for O2 or other gases if the O2 injection block was to fail closed. Of course the procedure would be to ensure to first isolate the diluent/bailout gas feed before pressing the button and injecting from the diluent block. If the diluent block was to fail closed the diver could simply add diluent from the BOV by switching to the OC on the BOV, inhaling, switching back to the closed circuit and then exhaling in the loop. If the block fails open, the diver can isolate or shutoff until diluent is needed and then turn it back on for a moment to supply diluent, and then off again.