The Electrolung
Posted By Walter Starck on 23 January 2004
Development of the Electrolung came about through a chance meeting of John
Kanwisher and I aboard Ed Link's diving research vessel Sea Diver in
the Bahamas in early 1968. Ed was trying out his new diver lock-out
submarine Deep Diver and had invited along several researchers with
relevant interests. I was there to do some deep biological collecting and
John was there to do heart rate/respiration measurements on divers using
some new acoustical telemetry equipment he had developed.
Lock-out dives from Deep Diver were done using hose fed open circuit
Kirby Morgan helmets. Gas for this purpose and to pressurize the lock-out
chamber was supplied from a large high pressure sphere carried by the sub.
The large amount of gas required for a single dive severely limited the
number of dives which could be made and involved substantial cost and
logistic considerations. The need for more efficient utilization of gas was
clearly apparent.
It turned out that John and I had both been
considering the feasibility of a mixed gas closed circuit rebreather using
electronic sensors to control PPO2. We both knew in general terms what was
needed but John wasn't a diver or a machinist and I didn't know that much
about electronics. However, I had been diving for 15 years and had built a
wide range of underwater equipment and John, in addition to being a
physiologist, had invented the first polariographic oxygen sensor and held a
dual appointment at Woods Hole Oceanographic Institute and Massachusetts
Institute of Technology where he lectured on electronic instrument design.
When we returned to our homes John started putting together the sensors and
control circuit and I started designing the hardware and finding or
machining the components. Six weeks later we both had our respective parts
together. John sent me a bread board controller circuit and sensors. I
installed them and a few test dives showed that it indeed worked. The
overall concept and design appeared good but there were of course, numerous
details to clean up. The electronics for example were wire connected on a
breadboard and the solenoid valve I had hand made using a solenoid scavenged
from a battery operated cuckoo clock.
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