Fitting the original automatic diluent valve on the Inspiration
When I bought my Inspiration in 2000, the original model did not have an Automatic Diluent Valve (ADV). To dive with the rebreather, the diluent button had to be used during the descent to regularly supply gas to compensate for the ambient pressure. Sometimes, therefore, it happened that the diluent inflator was disconnected or forgotten to be connected, with the result that the loop was compressed by the increasing pressure and breathing from the circuit was impossible. It was then necessary at that point to switch to OC.
It was therefore a great relief when an automatic valve became available for the Inspiration that injected diluent into the loop as soon as needed. The process is completely automatic. For safety, another shut-off valve (‘slide valve’) was built into the supply. Should the gas supply ever get stuck in the open position, an uncontrolled ascent could be prevented by closing this slide.
On this page I show the actions to add an ADV to your rebreather.
This shows how the ADV set is delivered. The shut-off valve is additional to the ADV-setInstructions are provided with the valve! (see bottom of this page!)The standard T-piece spanner is a simple tool, not very effective. You can obtain stainless steel fasteners from several addresses.The spanner fits the T-pieve perfectHold the ring inside the CL and release the connector You can now take the T-piece off and sand from all over the world is released 😉Unclip the counter lung and open the counterlungFind the zipper and take the counterlung out.You can remove the counter ring nowThe area that was clamped between the rings need to be thoroughly cleaned.I used up my old Christmas serviettes with a special solvent that is oxygen compatible called Biox, to clean this area.Push the counter ring in the lungand center the ring in the lungNow push back the inner counterlung in the outer counterlung and push the ring through the fabricHere you can see the addition mechanism and leverDiluent supply by a swivelling connector.When you order an ADV tell APD if you own a old or new style rebreather. The older models have the same hose connector on inhale and exhale side. That has been changed for the newer models.Don’t forget to place the O-ring, and put some grease on it. I use only oxygen compatible grease although this could be argued with.Connect the IP hose of the ADV to the distribution bar.Then screw the ADV on the counterlungThe connection between the IP hose and the shut-off valve is a O-ring connection and made without tools.Test the rebreather with the proper procedure for under-pressure.Mound the Audio alarm, and the job is done.
Therebreathersite was founded by Jan Willem Bech in 1999. After a diving career of many years, he decided to start technical diving in 1999. He immediately noticed that at that time there was almost no website that contained the history of closed breathing systems. The start for the website led to a huge collection that offered about 1,300 pages of information until 2019. In 2019, a fresh start was made with the website now freely available online for everyone. Therebreathersite is a source of information for divers, researchers, technicians and students. I hope you enjoy browsing the content!
