Powered by Invision Power Board


Forum Rules Forum Rules (Please read before posting)
Pages:123 ( Go to first unread post ) Reply to this topicStart new topicStart Poll

> Supercritical Co2 Chamber., with sight glass.
AwesomeMatt
Posted: May 08, 2012 06:39 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,047
Member No.: 9,878
Joined: June 21, 2007





Magnificent.

So, umm, the fix for that is... rebuild the whole lid thicker?

Goddamn that's a lot of pressure.
PMEmail Poster
Top
CWB
Posted: May 08, 2012 12:41 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 21,480
Member No.: 15,154
Joined: May 15, 2008




have you measured the expansion of the cylindrical section as well ?
i dunno ... a stronger/thicker material perhaps ?
hopefully the seal will always give way before the cover and fasteners do .


--------------------
"Know how to solve every problem that has been solved"
R. Feynman '88
PM
Top
Sch3mat1c
Posted: May 08, 2012 02:40 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 19,607
Member No.: 73
Joined: July 24, 2002




What is it, 1/4" plate? Could stand to be doubled up... double the thickness means double the strength and quadruple the stiffness.

It would be handy to calculate just how much the deflection is / should be, but strain calculations aren't something I'm familiar with, and most problems involve matrix or tensor solutions. On the plus side, since MEs and AEs need to know some of these things and most sleep through such classes, many coefficients are tabulated, so it's probably not too hard to figure out.

Tim


--------------------
Answering questions is a tricky subject to practice. Not due to the difficulty of formulating or locating answers, but due to the human inability of asking the right questions; a skill that, were one to possess, would put them in the "answering" category.
PMEmail PosterUsers Website
Top
johansen
Posted: May 09, 2012 01:00 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,160
Member No.: 10,912
Joined: September 06, 2007




The top plate is about 14-15 mm thick, it was 16mm but i took it down to 15 to get through all the rust pits.

I could weld one or more 1/4th inch thick plates 5.5 inches in diameter on top of the existing plate, with a 1 inch diameter hole in the middle for the pipe to go...but I would need to pre-stress the 1/4th inch thick plate or it is not going to add much.... which is doable I suppose but it would just be easier to start over again, cutting a 8 inch diameter circle out of a rail road tie plate, which is .860 inches thick (the ones i have are anyway)

As far as I read into it, for an 8 inch diameter flange (for a 4 inch diameter pipe), 1000 psi working and 3-4 kpsi test, the books say to use something on the order of 1 inch thick plate, and (8) 1 inch diameter bolts to hold the flange together. But this is for a flange, not an end cap.


@ CWB the pipe section i used is sch 80, 2300 psi working, 9000 psi burst.



So for the moment i'm going to just use it as is without cutting a viewport.

but i'd really love to have a viewport for a 3 kpsi hydro, or ~1200 co2 chamber...


--------------------
9/11 was really a prototype steel smelter that runs on naturally aspirated jet fuel and phosphorus.
PMEmail PosterUsers Website
Top
MikeGyver
Posted: May 09, 2012 06:38 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 1,274
Member No.: 12,151
Joined: December 05, 2007




If you're going to weld you could just weld a couple stiffeners across the top. you will have warpage issues if you want a machined fit on the bottom. Probably bes tto machine it flat on the bottom afterwards.
PMEmail Poster
Top
tekwiz
Posted: May 09, 2012 06:44 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




Either weld gussets onto the top of the lid, or cut out a clamp ring from the same material & use it under the ring of(longer) bolts. This doesn't have to be flat, only smooth on both sides. The clamping pressure will flatten it out, along with the lid. For best results, keep the center hole as small as practical.

BTW: You must keep total clearance under .002" to prevent elastomer extrusion...preferrably under .001". If you can't achieve this, you will require a gasket material much stronger, or that contains fibers.
A Teflon washer should work, provided it has enough width & isn't too thick. So would polyethylene, if the temperature isn't too high. Both are food safe at normal temps.


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
johansen
Posted: May 17, 2012 11:08 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,160
Member No.: 10,912
Joined: September 06, 2007




so i used half a box of 6011 1/8th inch rod....

user posted image

3500 psi using a lead seal. and that's 2300 pounds per bolt.
I'm going to grind that weld down farther and then put another layer of metal down, then start machining the hole for the lens.


--------------------
9/11 was really a prototype steel smelter that runs on naturally aspirated jet fuel and phosphorus.
PMEmail PosterUsers Website
Top
CWB
Posted: May 18, 2012 10:54 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 21,480
Member No.: 15,154
Joined: May 15, 2008




how long did it take to burn up that half box of rod ?
(i take it that you mean the cracker box sized cans)


--------------------
"Know how to solve every problem that has been solved"
R. Feynman '88
PM
Top
johansen
Posted: May 18, 2012 10:58 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,160
Member No.: 10,912
Joined: September 06, 2007




oh i don't recall.

i did it all at one time so the plate got to about 1000F and after the first layer was put down, (which i did in a radial pattern) the plate returned to its original flat condition. i then started welding over the radial welds in a circular manner.

I actually took measurements this time so i'll be able to get a measure on the displacement.


--------------------
9/11 was really a prototype steel smelter that runs on naturally aspirated jet fuel and phosphorus.
PMEmail PosterUsers Website
Top
tekwiz
Posted: May 19, 2012 06:51 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




Why go through all that trouble & expense to build up the plate, instead of merely welding a few ribs to it to stiffen it?


BTW: Did you know that high pressure sight glasses are commercially? One type, you may be able to make yourself, if you're careful:
http://www.visilume.com/technical/metaglas-sight-glass.html This place offers uniquely constructed composite sight glasses up to 1000bar, that can simply be bolted on to a flange. The construction they use lends itself well to DIY.

This place has sapphire & glass sight glasses up to 30MPa, some with NPT threads: http://www.precisionsapphire.com/products/..._pressure.shtml



--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
johansen
Posted: May 19, 2012 07:09 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,160
Member No.: 10,912
Joined: September 06, 2007




uh because it was fun practice welding.

i just wasn't seeing it with the ribs, and it woud have been just as much effort cutting and grinding them down and then trying to get the welds done right without warping the plate.

I do have enough tin i could float the glass on top of it while trying to melt it inside a steel ring... that is very interesting, though i wonder what kinds of glass and steel it needs in order to fuse.


--------------------
9/11 was really a prototype steel smelter that runs on naturally aspirated jet fuel and phosphorus.
PMEmail PosterUsers Website
Top
tekwiz
Posted: May 19, 2012 07:38 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




QUOTE (johansen @ May 19, 2012 10:09 am)
uh because it was fun practice welding.

i just wasn't seeing it with the ribs, and it woud have been just as much effort cutting and grinding them down and then trying to get the welds done right without warping the plate.

I do have enough tin i could float the glass on top of it while trying to melt it inside a steel ring... that is very interesting, though i wonder what kinds of glass and steel it needs in order to fuse.

That info should be easy to find. There are a lot of applications for metal/glass bonds in industry, so the info should be standardized..
Glass type would most likely be borosilicate or quartz, because of their very low coefficients of expansion.
There are also limits to the compression attainable...limited to the tensile strength of whatever metal is used. Flatness of the composite glass & it's mounting surface is absolutely essential, as I'll bet those glass assemblies crack very easily if warped.


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
CWB
Posted: May 20, 2012 12:49 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 21,480
Member No.: 15,154
Joined: May 15, 2008




i'll bet they crack easily too .
sony had a run of the small crts that they used in their projection sets (they sold them to other outfits as well) .
the "fritz seal" of the crt face plate to the bell was the problem .
even with careful torquing of the mounting hardware the expansion and contraction differentials stressed it enough to crack the seal at the interface between materials .
the glycol coolant got sucked into the crt ... this was not a good thing when the set was in operation .

the first time i had to repair one of these sets (under warranty) i walked over to the other tech with the crt in hand and showed it to him .
he watched the glycol slosh around inside the crt .
i said "so much for a fluid drive crt ..." .
laugh.gif


there were problems with the metal-to-glass seal with some types of vacuum tubes over the years .


--------------------
"Know how to solve every problem that has been solved"
R. Feynman '88
PM
Top
tekwiz
Posted: May 20, 2012 05:55 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




QUOTE
the glycol coolant got sucked into the crt ... this was not a good thing when the set was in operation .


I'll bet it sure looked cool on screen when it happened, especially in the first couple of seconds. tongue.gif


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
MikeGyver
Posted: May 21, 2012 09:45 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 1,274
Member No.: 12,151
Joined: December 05, 2007




lol...
Two half circle gussets intersecting each other in the middle at right angles, or a tube a couples inches tall and about the half the diameter of the cap welded to it, centered. The second method will keep any warpage axial to the bolt circle so it probably wouldn't matter, plus even if it did you can just plane it like before on the mill.
PMEmail Poster
Top
johansen
Posted: June 08, 2012 07:21 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,160
Member No.: 10,912
Joined: September 06, 2007




user posted image

so far i'm stuck at 400 psi with turbo classic yeast and table sugar. smile.gif

no, this isn't the only reason i made this thing.
i was stuck at 360-380 psi for 3 days, but since yesterday the pressure has started climbing again. I killed the first batch at 260 psi, i left it out in the sun too long and the yeast died.


--------------------
9/11 was really a prototype steel smelter that runs on naturally aspirated jet fuel and phosphorus.
PMEmail PosterUsers Website
Top
johansen
Posted: June 16, 2013 03:29 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,160
Member No.: 10,912
Joined: September 06, 2007




http://johansense.com/bulk/supercriticalco2/P1050206.JPG

and the damage.

due to human error i ended up milling the cavity for the wrong side of the glass i'd intended to use.

there also must have been only 5 thousanths of an inch thick layer of epoxy between the glass and the metal. so the glass cracked at hardly 800 psi.
so when the lid bowed outward it would have put all the pressure on the outer perimeter of the glass.
although the 1/8th inch ntp pipe fitting leaked on my grease gun, due to all the metal removal, i think the lid was significantly weaker than it was before, so i have no idea. should have measured how much the lid expanded i guess. but the hole in the center was only 1.3 inches in diameter.

I have a piece of metal plate that is a full .75 inches thick that i could use as a lid.. not sure what the best way to make a window that can hold back 2000 psi is... any ideas?


--------------------
9/11 was really a prototype steel smelter that runs on naturally aspirated jet fuel and phosphorus.
PMEmail PosterUsers Website
Top
AwesomeMatt
Posted: June 16, 2013 06:00 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,047
Member No.: 9,878
Joined: June 21, 2007




I thought you turned this into a BBQ or something?
PMEmail Poster
Top
johansen
Posted: June 17, 2013 12:02 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,160
Member No.: 10,912
Joined: September 06, 2007




that was the 25 gallon propane tank smile.gif

this is referred to as a bomb. tongue.gif
I might try making some sodium in it.
apparently, magnesium and sodium hydroxide react to make sodium and some other components..but you have to do it in a closed container to recover much of it.


--------------------
9/11 was really a prototype steel smelter that runs on naturally aspirated jet fuel and phosphorus.
PMEmail PosterUsers Website
Top
Sch3mat1c
Posted: June 17, 2013 12:15 am
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 19,607
Member No.: 73
Joined: July 24, 2002




And because sodium metal has a low boiling point, and the reaction proceeds at a high temperature, well... the name (bomb) is fitting. smile.gif

Tim


--------------------
Answering questions is a tricky subject to practice. Not due to the difficulty of formulating or locating answers, but due to the human inability of asking the right questions; a skill that, were one to possess, would put them in the "answering" category.
PMEmail PosterUsers Website
Top
MacFromOK
Posted: June 17, 2013 12:34 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 14,201
Member No.: 5,314
Joined: June 04, 2006




Yikes... keep yer head down. blink.gif


--------------------
Mac *

"Basic research is what I'm doing when I don't know what I'm doing." [Wernher Von Braun]

* is not responsible for errors, consequential damage, or... anything.
PMEmail Poster
Top
johansen
Posted: June 17, 2013 12:54 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,160
Member No.: 10,912
Joined: September 06, 2007




the last experiment i did with lead oxide, and some aluminum pieces and a carbon arc torch ended with a lot of explosive splatter...

unfortunately, there's no good place around here to get sodium hydroxide, and i'm not about to make my own.


--------------------
9/11 was really a prototype steel smelter that runs on naturally aspirated jet fuel and phosphorus.
PMEmail PosterUsers Website
Top
CWB
Posted: June 17, 2013 01:18 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 21,480
Member No.: 15,154
Joined: May 15, 2008




yep ... i suppose buying small cans of "lewis lye" at the supermarket is pricey .


--------------------
"Know how to solve every problem that has been solved"
R. Feynman '88
PM
Top
Geek
Posted: June 17, 2013 08:26 am
Reply to this postQuote Post


Moderator
Group Icon

Group: Moderators
Posts: 9,943
Member No.: 62
Joined: July 23, 2002




Aren't Draino crystals a good deal sodium hydroxide?


--------------------
-= Gregg =-
"Ratings are for transistors.....tubes have guidelines"
(please do not PM me for advice. Non-forum business messages will be ignored)
PMUsers Website
Top
CWB
Posted: June 17, 2013 08:53 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 21,480
Member No.: 15,154
Joined: May 15, 2008




the key words : "a good deal" .
the rest of the mixture would screw up the reaction .

which reminds me ... i have to replace a couple of sections of the kitchen sink drain .
after 30 years a couple of the elbows corroded through (pin holes) ... cheap junk !
a little duct tape has sufficed for a week . dry.gif
laugh.gif


--------------------
"Know how to solve every problem that has been solved"
R. Feynman '88
PM
Top
0 User(s) are reading this topic (0 Guests and 0 Anonymous Users)
0 Members:

Topic OptionsPages:123 Reply to this topicStart new topicStart Poll

 


:: support us ::




ElectronicsSkin by DutchDork & The-Force