Re: bomb recharge procedure???

[Orin Eman <orin@WOLFENET.com>]

> >Anyway, when folks talk of the bomb being at 2000 psi I guess that means
> >its _initial_ pressure; and that new bombs are shipped dry (empty of
> >hydraulic fluid) at first? If so, the "membrane" needs to be pretty rigid
> >to be able to retain that initial nitrogen charge against merely
> >atmospheric pressure (?). I hadn't thought about that before this thread.
> the "membrane" needs to be flexible enough to stretch to the opposite
> wall until a sufficient quantity of incompressible fluid (hopefully
> pentosin) is pumped into the empty side of the chamber...

The natural shape of the diaphragm is probably close to that of the
wall and in the 'dry' state, pressed agains the wall.  Only the
section against the hydraulic oil inlet may be taking the full pressure
unsupported.  I say may because it will undoubtably be reinforced
in this area and may well have a metal insert at this point.
(The picture in the Bosch automotive handbook shows what it
calls a 'plug' at this point.)

The Bosch automotive handbook also notes "the pressure variation
between  the initial gas pressure and the maximum operating pressure
should not exceed 1:8 for diaphragm accumulators".
Or, to paraphrase a little, dry, the gas pressure is considerably
less than the system operating pressure.

Orin.