Recently I was able to buy a
complete Pirelli LS-901. On this page you find all details about my
collectors item ;)
First I will start with the manual.
I would be very pleased if someone would translate the manual for me. Page
per page is OK, no rush!
Since this page has been
damaged, I have this page from another manual:
Next part of the pirelli project is to get all parts working
again and clean the unit. The counterlung has to be repaired and there are
some cracks in the mask.
Here you see all the brass
parts cleaned and polished. The conical Bailout valve is greased with oxygen
compatible grease. When the diver is on the surface he can open the DSV and
breath fresh air.
Inside of the mask.
Very old hose clamp ;)
Divers Surface Valve
Here is the breathing hose
connector that is fitted to the scrubber
The next part of this restoration is the constant mass flow
valve. This valve is a very nice designed mass flow valve. On page 12 of the
manual you find that the constant mass flow can be adjusted during the dive.
When the diver is short of oxygen due to his metabolic rate, he is able to
bypass the valve with a hand lever. The valve is build completely from brass
and some parts from stainless steel.
Rubber made in 1943 does not last 65 years unfortunately....
since spareparts are not available they need to be made by
The finished mass flow valve.
Here you see the quality of
the soldering. One of the remarks in the NEDU report. (Follows later)
Now I have been promised to
receive a better counterlung. So when this has arrived the unit is
To follow: Counterlung + Nedu report about the LS 901 written in 1954