I think you are inferring the same thing.
“as a general rule, the valve is completely clean and opened only once for the
discharge. It is never throttled or closed once propellant has been introduced”
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
<http://www.cesaronitech.com/> http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> On Behalf Of
Troy Prideaux
Sent: Sunday, July 7, 2019 9:30 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Vacuum processing of solid propellant
It’s probably been >10 years since I last used that mixer, but if I ever do
drag it back into life again, I’ll consider it. Mind you, the propellants I was
playing with are relatively pretty insensitive and the ball valve is cleaned
out upon each use.
I’m struggling to envisage how much of a trapping issue there is though ie.
The process is started with the valve closed (ingredients added & mixed)
When ready for casting, the valve is opened fully.
The ‘fluid’ is transferred (gravity fed) through the fully opened valve until
the hopper is empty
The hopper with valve attached is removed for cleaning with the valve still in
the fully open position.
There’s no time when the valve (with open ball full of product) is closed like
a typical cryogenic or even typical industrial fluid processing application.
Also, there’s a fair bit of hysteresis with the flow of typical solid
propellant mixtures so there generally is a workable about of time allowable
for value opening action without significant concern of creepage into outer
cavities.
Troy
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
[mailto:arocket-bounce@xxxxxxxxxxxxx] On Behalf Of anthony@xxxxxxxxxxx ;
<mailto:anthony@xxxxxxxxxxx>
Sent: Monday, 8 July 2019 10:33 AM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Consider a plug instead and here’s why. As with cryogenic systems, it presents
a trapped working fluid. In this case, the working fluid is propellant. The
next issue is dependent on the valve and seat design as well as materials. If
the propellant is at all sensitive or any fines are present (there usually are)
there is the potential for sufficient shear and/or friction to cause
initiation. The situation quickly becomes more problematic if the propellant is
trapped.
I have seen ball valves used in industry for propellant discharge but as a
general rule, the valve is completely clean and opened only once for the
discharge. It is never throttled or closed once propellant has been introduced.
The use of ball valves in propellant discharge equipment is prohibited in our
facilities. Cove cut valves are used exclusively.
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
<http://www.cesaronitech.com/> http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
<arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx> > On Behalf
Of Troy Prideaux
Sent: Sunday, July 7, 2019 8:02 PM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Yup, that’s the dump (actually casting) valve. So the ball’s stem (it’s a ball
valve) is loosely coupled to an o-ring sealed sleeve with the handle attached
through the outer stainless steel casing/jacket that allows vacuum operation of
the valve; which allows the casting whilst still under vac & while even the
mixing paddle is still rotating. As illustrated this can be removed to enabled
the main mixing hopper to be removed for cleaning or whatever.
BTW: what’s not illustrated there is a paddle height control at the very top of
the main spindle shaft. This allows for adjustment of mixing paddle during
operation (under vac mixing). This is a *really* useful function for different
mix viscosities allowing me to strike the right balance (stuff sticking to
paddle vs sticking to mixing hopper) for very small mixes and it also helps to
minimise wastage as I can set it low enough to virtually scape the hopper at
the end to ensure just about everything is transferring into the casting
tube(s).
Troy
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
[mailto:arocket-bounce@xxxxxxxxxxxxx] On Behalf Of anthony@xxxxxxxxxxx ;
<mailto:anthony@xxxxxxxxxxx>
Sent: Monday, 8 July 2019 9:35 AM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Well done. Is that a valve at the bottom of the bowl?
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
<http://www.cesaronitech.com/> http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
<arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx> > On Behalf
Of Troy Prideaux
Sent: Sunday, July 7, 2019 7:26 PM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
No, it’s a totally custom made contraption
http://www.propulsionlabs.com.au/mixer/
Mixes and casts under vac with optional dry gas purge/re-pressurizing at the
end.
Cheers,
Troy
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
[mailto:arocket-bounce@xxxxxxxxxxxxx] On Behalf Of William Claybaugh
Sent: Monday, 8 July 2019 8:57 AM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Troy:
What mixer do you use under vacuum? Is it modified for this use or did you
find one? If modified, what did you do to it?
Bill
On Sun, Jul 7, 2019 at 4:53 PM Troy Prideaux <troy@xxxxxxxxxxxxxxxxxxxxx
<mailto:troy@xxxxxxxxxxxxxxxxxxxxx> > wrote:
This is why I do all my mixing and casting under vac. Normally NCO will favour
H2O over OH in terms of reactivity although OH groups do some in various
different reactivities.
Troy
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
[mailto:arocket-bounce@xxxxxxxxxxxxx ;<mailto:arocket-bounce@xxxxxxxxxxxxx> ] On
Behalf Of 1bcjolly
Sent: Monday, 8 July 2019 5:09 AM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Some suggestions:
1) Do you dry your AP? I have found that AP contains moisture, supposedly
from absorption from the atmosphere. This water can be driven off by drying at
a temperature of 240 F. Drying the AP before mixing should also help the cure
if you are using OH/NCO chemistry since moisture contamination uses up NCO
functional groups.
2) Use slow mix speed. Baking type mixers on almost any speed will introduce
air into the mix.
Barry C
Sent from my Sprint Tablet.
-------- Original message --------
From: Anthony Cesaroni <anthony@xxxxxxxxxxx <mailto:anthony@xxxxxxxxxxx> >
Date: 7/7/19 14:43 (GMT-05:00)
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Discharge machine extra.:-)
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
<http://www.cesaronitech.com/> http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
<arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx> > On Behalf
Of William Claybaugh
Sent: Sunday, July 7, 2019 12:40 PM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Vacuum processing of solid propellant
I ran some static tests recently using a modified version of the standard RRS
composite propellant (10% Al rather than 7%). Those tests included applying
vacuum to the fully processed mix ahead of casting (5 minutes); the mix was
still outgassing when we repressurized
This resulted in an about 5.6 % increase in density, of which 0.9% is
attributable to the increased Al loading.
Given that full mixing under vacuum is not viable given the processing
equipment available at the MTA, is there another vacuum schedule that might
provide still higher density?
Does degassing the liquid components before mixing help or does the subsequent
mixing just reintroduce air? Any recommendations on degassing time after
mixing (recognizing that the catalyst is in the mix at this point).
Two static tests, one at 390 psia average and the other at 760 psia average
showed a decreased burn rate and a slightly higher ISP as compared to the
original mix, as expected.
Bill
Attachment:
image001.jpg
Description: