Re: bomb recharge procedure???

[Phil and Judy Rose <pjrose@servtech.com>]

>Date: Mon, 1 Dec 1997 00:46:13 -0800 (PST)
>From: Orin Eman <orin@WOLFENET.com>
>Subject: Re: bomb recharge procedure???
>
>> >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.

So the arrangment is actually more like a sphere within a sphere? Hmm, I
had naively assumed that the membrane divided the accumulator into
more-or-less equal volumes. Does the Bosch handbook state the initial
pressure?
Also, what _is_ the nominal value (or range) of "operating pressure"?

Phil

         **********************************************
         *  Phil & Judy Rose     E-mail:              *
         *                       pjrose@servtech.com  *
         **********************************************