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4hv.org :: Forums :: General Science and Electronics
<< Previous thread | Next thread >>   

Liquid Oxygen.

Author Post
Sat Jul 15 2017, 09:23PM Print View
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5232
Has anyone used and have experience with small Dewar flasks? I need 2 or so pounds or a gallon or so LOx. Ive got others who have experience with larger containers but id like some more background from others here on the forum. Also what about cost, per Kg ? it seems like its been going up here in the US over the past few years. Ive dealt with Helium (US$ 5000 at a time) and such, but i dont want 900 Kg of O2 in my backyard and let it go nuclear-boom so i plan to buy as needed.

Ill be using that small quantity in the Nevada desert with permission from the Fire Marshall and the FAA and we do many different types of testing at our site some fly some are attached to the ground, then roll back to California for analysis. I cant talk to much about it due to intellectual property and other peoples money at stake and NDAs.

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Sun Jul 16 2017, 02:33AM
Registered Member #65
Joined: Thu Feb 09 2006, 06:43AM
Posts: 1124
Liquid O2 is usually handled at cryogenic temperatures for safety reasons (some use a liquid nitrogen bath to re-liquefy an O2 gas generator source), and many others prefer chemically stabilized oxidizers for hybrid engines etc.

For small quantities, demonstrators will use a portable high pressure 1L transfer bottle, and transfer pump rig (very similar to NOS inverted-bottle fillers). Remember, many oils and or organic contaminants are an ignition source, and there are plenty of accidents that happened working on a wood surfaces.

Note, Welding gas suppliers of Oxygen are a fraction the cost of medical or lab grade gas, and they charge by weight.

NDA/contracts happen to everyone when they first enter the private sector, but always get a local lawyer to verify the freedom to do your own projects is protected.
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Sun Jul 16 2017, 06:47AM
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 2800
Rather than transporting LOX you could consider something like this ?
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Mon Jul 17 2017, 02:46AM
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5232
the NDAs pretty much screw me out of my work here, but i have to start somewhere.

Also, Hybrid engine ? you just made a wild allegation which i neither confirm nor deny.
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Mon Jul 17 2017, 03:20AM
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1501
I have witnessed LOX production by amateurs, in 100 ml quantities, simply by chilling gaseous oxygen with LN2. A vertical hole in the top of a block of paraffin wax, filled with liquid oxygen, IIRC could become a primitive rocket engine. Don't know if the term "hybrid" was as popular in rocket science then as it is now.

When I was in college, research groups would exchange their empty 160 liter liquid nitrogen dewars for full ones at the Central Stores facility on campus. Charged on the books at 7 cents per liter ($0.26 per gallon)-- that was in the 1970's. Who can tell us what the exchange costs today at a gas products company?

In the early days of general Internet awareness (1995), George Goble at Purdue became famous for a video from annual department picnic. George would get a barely-started charcoal barbecue ready to cook in 5 seconds by pouring on some liquid oxygen (from container at the end of a long pole).

I corresponded with George in the early days of email. Learned that more "pure" oxygen is used for medical purposes than for welding etc. When I noted the thermodynamic similarity between CO2 and N2O, George confirmed my speculation that "dry nitrous ice" exists. It was a familar sight where nitrous cylinders were filled (e.g. for motor racing) and vented N2O impinged on a surface.
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Mon Jul 17 2017, 05:38AM
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5232
Is 40% h2o2 and 60% h2o flammable if heated by spark (non-hypergolic decomposition) on a surface similar to urethane, paraffin or acrylic ? Im trying to go over the stoichemetry in my head.
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Tue Jul 18 2017, 05:28AM
Registered Member #65
Joined: Thu Feb 09 2006, 06:43AM
Posts: 1124
NASA uses Hydrazine fuels for Augmented Catalytic Thrusters, as Hydrogen peroxide will slowly decompose on its own.
However, H2O2 + Kerosene is a very popular propellant (IIRC 400lb thrust engines are <$3000), and even SpaceX did quite a bit of private sector work in this area.

Our company has endured issues with compromised supply chains, communications, and intellectual property. Some even plagiarized the internal documentation after incorrectly assuming it was common in the public domain (US & UK company with a $1.5B market cap... because freedom...) After awhile, you will realize that ALL industrial & political ecosystems are full of mosquitoes, you probably had NO external allies, and the best plans simply do not require secrecy to succeed. Indeed, we are not under ITAR rules here, but if you are than I can't legally help you.

You may also learn that legal mistakes can cost far more than you can predict at this stage of your career.
Shares can evaporate as many people get pushed out of startups prior to sale, and worst of all -- you may get bored.


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Tue Jul 18 2017, 09:00AM
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5232
Carbon_Rod wrote ...

.... and worst of all -- you may get bored.

My greatest fear.
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