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Had this reply off line from the famous Karl
Stanley re air compensation,
asked him if he minded me posting his reply as I
thought it was good, & he said "no problem"
Alan-
I air compensated motors on both my subs-
it is quite easy- use a 1st stage scuba regulator- and take out the spring- (now
the minimum amount of pressure needed to move the piston or diagram will be the
pressure inside the motor- you can tap 1/8th npt into the LP
ports- I let the shaft seal on the motor bleed out the pressure on the way
up- I have used this to 2660 feet-
Went down to the dive shop with my old first stage & got them to pull
it apart & yes very easy to modify.
I'm going to try some small springs to over pressurize the motors a bit
& put a pressure relief valve in the system rather
than letting the air leak out the shaft seal on expansion.
The first stage without spring also looks like a good option
for equalizing an ambient sub. Using a second stage seems
to be the norm, but it's fragile diaphragm looks vulnerable if
there is a pressure differential caused by the slow equalization
of the hull during descent Was sucking in water from a perforated diaphragm
on my last scuba dive so became aware of the
diaphragms fragility.
Regards Alan
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