Thank you for this. I do know that there are places on campus that handle
LOX regularly so I will definitely talk to those research labs about
training. I also would agree that I need to shadow a liquid launch to
understand how a lot of different things are done. I will try to schedule a
trip out to FAR for this purpose.
Zachary Martinez
Aerospace & Mechanical Engineering
Missouri S&T
On Wed, Sep 28, 2016 at 6:21 PM, Ben Brockert <wikkit@xxxxxxxxx> wrote:
LOX is stored and transported in a dewar, which is a large vacuum
flask like a Thermos, usually between 80 and 280 liters. The
difference between a LOX dewar and a coffee thermos (or a liquid
nitrogen dewar that you'd make ice cream with) is that the LOX dewar
is pressure rated, and indeed the liquid is stored under pressure to
reduce boiloff. The pressure depends on how long ago the dewar was
filled and the model of dewar, but it is between 25 and 250 psi.
To load LOX into a tank you connect the dewar to the plumbing via a
hose, open appropriate valves, and flow into the tank. At no point in
the process should you ever actually see liquid oxygen, except
possibly spraying out of the vent when the tank is full.
The tank needs to have at least two connections to be useful, a liquid
drain and a gas vent. It almost always makes best sense to fill
through the drain and vent out the vent. They can be physically at the
bottom and top of the tank, but other architectures are possible as
well. Xombie has surplus Atlas tanks on it, which use a dip tube for
liquid drain, so both connections are physically at the top of the
tank. Armadillo's Mod rockets had both connections at the bottom of
the LOX tank, with a riser tube on the press/vent line.
You should not learn how to handle liquid oxygen by reading about it.
You should get hands-on training in the process. There's probably some
group at your university that handles cryogens and has a standardized
training process. FAR would also be a good place to see it in the real
world; you should email Kevin Baxter and ask if there are any upcoming
liquid launches that you can shadow.
On Wed, Sep 28, 2016 at 1:15 PM, Zachary Martinez <znm3m8@xxxxxxx> wrote:
Good Afternoon,the
I am trying to decide on the location of fill ports for the tanks top or
bottom. If I do it on the top I would either need two separate ports on
top into the tank or have bubbles of air rise up through the fillingEither
propellant as the air/GOX vents out. If I put the port on the bottom then
there are complications with how I feed the propellant into the tank.
it would be pressure fed into the tank or gravity fed and have plumbingknow
going up the length of the tank. Do I need to pour the LOX into a funnel?
Every way I come up with for filling ops either sounds unsafe or
impractical. I have looked everywhere but I can't seem to find a safety
guide for transferring liquid oxygen. Someone said a few weeks ago that
transferring or handling liquid oxygen is a very common procedure so I
there has to be a best practices or procedural guidelines already written
for this kind of thing.
Zachary Martinez
Aerospace & Mechanical Engineering
Missouri S&T
