[safety] How to make low pressure flow head w/pressure release

[k|ngp|n]

i think you where to busy playing a moviestar i guess .....lol

rofl..
Sorry if I didnt respond to a pm, I try to respond to all quickly as I can. Don't remember yours. Extera pm'd me so I thought I'd add to the thread with a helpful response and a mention of the safety factor for the new guys.

[wdrzal]

Thanks for your help Wdrzal!



You solution of making a pivot is nice, but I don't have enough room to store one. Pooring LN2 in my thermos like a beertender would be the best solution.

sure the beer spout solution would be nice but may be expensive and not compatible with all dewars. What ever solution be sure its completely safe as things go wrong quickly at -195c iirc

The device can be simple and take no more space than maybe a couple inches wider than a dewar.

the pivot points could be attached to long hose clamp that go around the dewar and tighten. Then all you need is a H frame with V notches in the top to set the pivot points in.Be sure they are deep enough so the pivots can't slip up and out or use a hold down over the pivots. 2 pieces of angle on the bottom of the H frame will give stability for the Base. add a handle to make tipping easier and more controlled. bearings if you are picky and like to do precision work.

simple if the other solutions cost to much. You could make one with punched angle iron and strapping and a few bolts in a hour or so.

[Johnny Bravo]

when do we get some sesults from johnny bravo

In good time Rol-co, trying to sort out LN2 for after Christmas

[T_M]

I have been riding in the car with the dewar shotgun, and I hit some rough road bumps (michigan roads lol) and the nitrogen actually popped the pump head off of the dewar and nitrogen gas and some liquid was spraying everywhere in the car , so bad I had to pull over and jump out. Without the safety leash attached the pump head to the dewar, there would have been a fountain of nitrogen going off in the car resulting in some serious injury. Not to mention the pump head can become a missile if it's not leashed on and secured tightly.

One of the reasons why in Australia the materials handling laws forbid the carrying of LN2 in an enclosed vehicle, it can only be transported secured in an open top vehicle or trailer (i.e. the tray of a truck/ute, or trailer).

[Extera]

The old fashioned way worked

[Jort]

olala nice overclocking extera is that best NL bear in the background? heineken

grtz

[massman]

Nice and clean bench setup, good results ...

Way to go Holland !

[Extera]

Thanks, the OC was board limited. The cpu want's to much higher.

[Ramaistro]

Dunno if this would work, it is just an idea....


The idea is that when you need some new LN2 you shutoff the blow-off valve with the tap and open the tap for the pump. This way the LN2 should go up in the pipe stuck in the midle. When done you close the tap for the pump and open the one for the blow off valve.

If it ain't an option tell me why plz...

[Extera]

well, i'd discovered my dewar has no overpressure valve. No unpressurized dewar has this kind of valve, the thing I though it was one, was the place where they vacuumed the dewar. Pressure just cant built up, since the dewar cant seal of using the normal lid.

Making a system Kingpin explained wouldn't be that hard. But what if the pressure release valve fails? I think there must be 2 pieces of rubber sealing the dewar, in this shape \\// the top rubber piece should be up very loose, but thight enough to allow 5psi of pressure. When the pressure builds up, the top rubber sould "pop" out a little, releasing pressure.

[T_M]

Pressure relief valve shouldnt fail, however your backup idea sounds feasible

[wdrzal]

The old fashioned way worked

Those pictures of "the old fashioned way" are extremely DANGEROUS . Where are your thermal gloves??????????

Have you ever consider what would happen if the glass inside the thermos cracked while in your BARE HANDS.

The Vacuum insulation would be instantly lost and that stainless steel your hands are on would be instantaneously be -195c your skin would instantaneously stick and freeze to the container. You would not be able to Let go until it warmed up. What if LN2 got trapped between the cracked glass and stainless steel outer casing???? and you could NOT even dump it all out quickly?????? How long could BARE HANDS hold on to something @ -195C before severe frostbite or even irreparable cell DAMAGE causing the AMPUTATION of both your hands would take???????

Do you now want to get serious about safety NOW????????????????, get some thermal gloves and wear Full face protection such as a clear flip up/down shield.

Merry Christmas: Walt.........please head this warning........it is not a far fetched scenario,Thermos glass cracks all the time just holding coffee or iced tea.

PS: I see thermometer reads -90c that dry ice range,but the warning is still the same.

[Extera]

more coldness wasn't needed because the board was the bottleneck here.

I did wear eye protection. and if the glass in the thermos would crack. the thermos would not cool down instantly. When pooring LN2 in the container. It takes about 30sec before the base is even sub-zero, altough there is less LN2 in the container, copper a better heat/cold conducter then the RVS of the thermos. The themos will cool down slow enough to notice.

When pooring LN2 out the dewar in the themos, i'd used powertorch gloves. This are the gloves the LN2 company also uses when filling the dewar.

[Entsafter]

Glass thermos??? WTF!!

Why don't you use double walled stainless steel -> nearly impossible to fail!

[G H Z]

Glass is used and recommended in a variety of lab settings, of course it can break but it's not out of the norm.

[wdrzal]

Glass is used and recommended in a variety of lab settings, of course it can break but it's not out of the norm.

Lab glass is tempered Pyrex,a common thermos bottle is not.

That thermos is OK to use as long as you have gloved hands with enough insulation to protect bare flesh if the above posted scenario would happen.

Knowing the potential dangers and extreme risks,all he had to do was put on the leather insulated gloves sitting on his desk to avoid possible crippling or losing both hands.

[G H Z]

Tabletop dewars are not made of Pyrex

I'll search more later but most recommend no gloves whatesoever walt, clothing or the incorrect kind of glove can cause more damage than if the skin is bare. Eye protection is a must.

[wdrzal]

Tabletop dewars are not made of Pyrex

I'll search more later but most recommend no gloves whatesoever walt, clothing or the incorrect kind of glove can cause more damage than if the skin is bare. Eye protection is a must.

This is where I take issue, if you have to search, that implies you do not know the accepted procedures that come from either a governmental regulating agency like OSHA (occupational safety & heath administration) or a well respected non-profit agency like RSES (refrigeration service engineers society)

In the direct die section I referenced wikapedia about some basic safety on 2 gas torches.BUT I made sure everyone knows wikapedia is a on line encyclopedia that all the content comes from users and is NOT edited for accuracy. And furthermore many peoples opinions or life long practices are presented as FACT.

This also applies to the INTERNET as a whole,much of the information is written and not professional edited for accuracy,much is correct on on a certain type/group of sites,mainly manufactures of a well know product or piece of equipment(but they still are biased and written to show their product in best light.
Information from governmental sites like NIST(national institute of standards & technology) and the previous mentioned OSHA and others in that category I trust for accurate information. Go to any electrical site and compare information with the NEC (national electrical code)rarely do you get complete accurate information. Thats why schools and colleges spend so much time choosing the professional written and edited text they teach our children from.but with that said getting accurate information off the net is risky at best, unless you are sure of the accuracy of the information and trust the site is edited for accuracy.

While XS contains a great deal of technical information and users who freely share it. XS enjoys a higher than most grade for accuracy & knowledge base as far as forums go. All most all post are opinions of the author. The moderators due a great job keeping spam and worthless BS to a minimum, the fact is XS like all most all forums are not full time professionally moderated and edited for accuracy of each post.

Just like much of this post,it is my opinion ,except where you can go to known sites edited for accuracy like a professional text book.

please everyone keep this in mind especially when it comes to your personal safety. I always try to respect each users personal opinion,BUT when it comes to safety, I will challenge any post that I believe is substantially dangerous. Not to do this would be un-responsible in my opinion as thousands of people will eventually read that advice.And Safety is always the #1 priority.

I want to wish everyone a Merry Christmas or a
Happy Holiday no matter what your religion is. But Always work safely so I can wish you the same next year.
Walt
PS: I consider XS my on line family,and care deeply about everyones safety. My posts about safety are not to spark a personnel argument,but to educate many of our young adults exposed to some of these potentially dangerous procedures,How to preform them safely using procedures not written by myself,but rules and laws passed along, usually written in blood before they were mandated .

[Gautam]

What happens generally if you spill a bit of LN2 on yourself? Answer- you never do spill it on yourself because it evaporates too quickly to hit your skin in liquid form. It's not like the LN2 is being actively cooled to those temperatures, in open air it will turn to gas...

That's why people recommend against using the wrong kind of gloves and most simply use none.

Btw, dry ice sublimates at -78.6, so -90 is out of its range.

[Xtasy]

put some armaflex around and everything is good

[wdrzal]

Btw, dry ice sublimates at -78.6, so -90 is out of its range.

I am fully aware of the temperature pure CO2(dry ice) sublimation tempeature and freezing points but the temperature is so far away from LN2 temperatures, I considered a bad probe,probe set to wrong type or one damaged by imersion when not intended for direct imersion or many other factors could all cause the descrepancy of 12 degrees if he was using dry ice

also taking into consideration Ln2 will not survive as liquid at -90c, I either assumed the pic was taken after the tube ran out of LN2 and already started to warm or he was using dry ice in that pic with one of the above listed dicrepancies occured.or the sublimation was not pure co2

[wdrzal]

Walt isn't an overclocker and probably doesn't know about having to control base temperatures by varying the amount of LN2 in the tube

Tom

Tom would be correct if you added the word "current overclocker"

I was around when oc'ing was a necessity, when a 33mhz CPU was pushed to 40 or when GUI interfaces where first introduced they brought a PC down to its knees,OC'ing was not for a hobby but must to try to get more work done faster. I had to add math co-pocessors to run CAD programs.IIRC that stopped aroud the 386 /486dx2 days.

I,ve been away so long I would be completely lost except for what I have learned & followered here at XS. In my case and in my business I can buy a Stock CPU's fast enough to run any CAD or modeling program I use. The absolute need for me is not there.

But I do understand whether you OC as a hobby, for gamming speed,for business purposes or scientific ones to push current technology to the limit and keep adding to the knowledge base to keep Moore's Law on track. The importance of information gained here at XS is taken very serious,at least by me.
Walt

[G H Z]

This is where I take issue, if you have to search, that implies you do not know the accepted procedures

No all it means is I want to find some links for you to make my point very very clear. If you're going to cite OSHA or some other 'official' guideline then by all means, please feel free to provide the information yourself

People realize there is risk in some of the things we do around here and I think you should respect personal freedom (I respect yours) and think about how you present your comments when you talk about safety here.

[Extera]

Well,

Unknown_Road and I have decided we will give it a try, but finding a pressure release valve with a value op 5 PSI (0,34 BAR) is near impossible.

Anyone here ho can get these valves? or is there an other solution?

[G H Z]

Here are some good options.

http://www.generant.com/vrv.htm