Where Did the “Standard” Power
Inflator Design Come From?
We touched on this briefly in the last issue of StupidDiverTricks.com. It bears further discussion.
Before the introduction of true buoyancy compensation devices, some divers wore what we today refer to as snorkeling vests. These more resemble the life vest stored in the plastic pouch under your airline seat than they do any sort of serious dive gear.
As originally used by divers, snorkeling-type vests could be used for surface flotation, but little else. The location of the inflation mechanism made it impossible to drain air from anything other than the lower half of the vest while under water.
The first true BCs differed from snorkeling vests in that they had a large-diameter inflation/deflation hose mounted close to the top of the vest. This made it easier for users to vent air from the BC on ascent. The catch was, you could only inflate these BCs orally (or, in the case of an emergency, possibly by using a highly unreliable CO2 cartridge that most such BCs came with at the time). A very few models — notably the French Fenzy and Spanish Nemrod — also had tiny air bottles that could be used to inflate them.
Not long after BCs first were introduced in the early 1970s, after-market power inflator units began to appear. These went in line between the large-diameter inflation hose and the oral inflation mechanism. By the early 1980s, these were pretty much standard equipment. This basic configuration has stayed with us through the present day.
From an engineering standpoint, there is no compelling reason to combine oral inflation, power inflation and deflation into a single unit. Among the first companies to try an alternative approach was US Divers (now AquaLung). Their BC II horse collar BC of the mid-1970s had a thumb-activated power inflator mechanism on the right-hand side, opposite the oral inflation/deflation hose. Built into this was a finger-activated deflation lever that operated a remote exhaust valve near the top of the BC.
Ultimately, US Divers switched to a more conventional design. Why?
- Their proprietary approach required a special low-pressure inflator hose that was not as readily available as more conventional designs.
- Use of their unique inflator mechanism was not familiar to divers trained on more conventional equipment.
- System components were not interchangeable. If you owned a BC II, but wanted to rent a regulator, odds are it would not have the special low-pressure inflator hose your BC required. And, because it used a non-standard oral inflation hose, you could not fit the BC with an integrated alternate-air-source inflator mechanism, such as the Scubapro AIR II.
Other manufacturers have experimented with alternate approaches to BC inflation. None have succeeded. Thus, a three-decades-old BC inflation configuration that evolved to meet needs that haven’t existed since the early 1980s is still with us.
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