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Alphanautics
Goonmaster
Registered: 11/26/07
Posts: 103
Last seen: 4 years, 2 months
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Rig up a thermometer for my PC through the blast valve?
#7727436 - 12/07/07 05:30 AM (16 years, 3 months ago) |
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Or whatever you call that rubber stopper thats supposed to be expelled when pressure reaches an unsafe level.. Could I just pop a meat thermometer through it, seal cleanly with silicon, and be good to read temperature on my beaster PC?
Also, wouldn't there be a difference in temp between the water and the steam? I would want to know the temp of the steam when autoclaving, right?
Thanks.
-------------------- Word em up
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veda_sticks
Cultivator
Registered: 07/29/07
Posts: 14,191
Loc: UK
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Alphanautics]
#7727440 - 12/07/07 05:33 AM (16 years, 3 months ago) |
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If you can get your hands on an infra red thermometer those are perfect for checking your pressure coooker, just measure the temperature at the surface of the cook.
-------------------- PF TEK - writeup by EvilMushroom666 Lets Grow Mushrooms - RogerRabbit & RoadKills website with sample videos plus the full PF TEK video series. Alot of great information - BUY THE DVD Cakes can and will pin! - So you think cakes suck for pins. Your wrong Franks Simple Coir/Verm Tek Franks Proper Pasturisation Tek Franks Spawning To Bulk - Monotub Professor Pinheads RTV Injection Port Tek Foo Mans No Soak WBS Prep Tek
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Nibin
Getting there
Registered: 11/29/05
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Re: Rig up a thermometer for my PC through the blast valve? [Re: veda_sticks]
#7727449 - 12/07/07 05:40 AM (16 years, 3 months ago) |
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Do not modify your pressure cooker, it is very dangerous and you could end up with an explosion.
Also, once the cooker is in full swing, at a given pressure the temperature will always be the same.
-------------------- Newcomers guide-----> For all things shroomy
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fastfred
Old Hand
Registered: 05/17/04
Posts: 6,899
Loc: Dark side of the moon
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Nibin]
#7727476 - 12/07/07 05:58 AM (16 years, 3 months ago) |
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I would suggest not jury-rigging a ghetto setup like that. If you want a temp, simply get a pressure gage that also has temp markings or put them on there yourself, or just make up a conversion chart for yourself.
You could also use any sort of thermometer to measure the surface temp of the PC, that should be plenty. There are various contact thermometers designed for similar purposes, just stick one on and you're good to go.
-FF
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Sillicybin
Registered: 02/14/05
Posts: 2,134
Loc:
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Re: Rig up a thermometer for my PC through the blast valve? [Re: fastfred]
#7727627 - 12/07/07 07:37 AM (16 years, 3 months ago) |
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If you try to silicone a thermometer into the fuse plug, you'll just end up with a thermometer flying across the kitchen. Silicone will NOT hold 15PSI by itself (not even 5 PSI, and possibly not even 1 PSI). It needs the clamping force of a fastener (bolt[s], or threaded pipe) to be able to withstand pressure.
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veda_sticks
Cultivator
Registered: 07/29/07
Posts: 14,191
Loc: UK
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Sillicybin]
#7727630 - 12/07/07 07:38 AM (16 years, 3 months ago) |
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that would be quite funny, but at the same quite dangerous
-------------------- PF TEK - writeup by EvilMushroom666 Lets Grow Mushrooms - RogerRabbit & RoadKills website with sample videos plus the full PF TEK video series. Alot of great information - BUY THE DVD Cakes can and will pin! - So you think cakes suck for pins. Your wrong Franks Simple Coir/Verm Tek Franks Proper Pasturisation Tek Franks Spawning To Bulk - Monotub Professor Pinheads RTV Injection Port Tek Foo Mans No Soak WBS Prep Tek
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Sillicybin
Registered: 02/14/05
Posts: 2,134
Loc:
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Re: Rig up a thermometer for my PC through the blast valve? [Re: veda_sticks]
#7727656 - 12/07/07 07:52 AM (16 years, 3 months ago) |
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As a sidenote, on the first PC I used (it was a Presto steely from Mal-Wart) I modded it to put on a pressure gauge since it didn't come with one. I tapped the lid with a 1/8" NPT tap and inserted the pressure gauge with some teflon tape. If you can find a thermometer in the range you need that is pipe threaded and can withstand pressure, there is the possibility of doing this.
But one other thing - if you know the pressure inside the PC, you (roughly) know the temperature inside.
http://missvickie.com/workshop/pressure.html#Temperature%20and%20Pressure%20Table
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grandesign
Mushroom Madness
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Sillicybin]
#7727758 - 12/07/07 08:42 AM (16 years, 3 months ago) |
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also regular silicon will melt at that sort of temprature i would think you would need a high temprature sealer, but i wouldn try it any way .
-------------------- who are you ? who am i ? This shit aint real !!!
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Sillicybin
Registered: 02/14/05
Posts: 2,134
Loc:
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Re: Rig up a thermometer for my PC through the blast valve? [Re: grandesign]
#7727770 - 12/07/07 08:47 AM (16 years, 3 months ago) |
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Quote:
grandesign said: also regular silicon will melt at that sort of temprature i would think you would need a high temprature sealer, but i wouldn try it any way .
Most RTV's melt above 350*F, which is well above the temperature of a pressure cooker.
High temp RTV (ie, Permatex brand) is rated for 650*F (intermittent.)
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derx
who run it
Registered: 05/29/03
Posts: 2,459
Loc: dx/dt
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Sillicybin]
#7727938 - 12/07/07 09:44 AM (16 years, 3 months ago) |
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i just read your original post.
PLEASE DONT DO THIS STUPID ASS IDEA!
-------------------- better living through chemistry OVERGROW the government!! it's not a war on drugs, it's a war on personal freedom, ok, thats what it is.
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Alphanautics
Goonmaster
Registered: 11/26/07
Posts: 103
Last seen: 4 years, 2 months
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Nibin]
#7730744 - 12/07/07 09:10 PM (16 years, 3 months ago) |
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really?? I had no idea that a pressure cooker would retain a pecific temperature at certain pressure levels... Where would I find more info on that.. esp. related to altitude (I'm upstairs)..
Thanks all
Also, the idea was the termometer would be relatively light, so in the event of an overpressurization (yeah, i make up words), the blast valve would still blast.
-------------------- Word em up
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fastfred
Old Hand
Registered: 05/17/04
Posts: 6,899
Loc: Dark side of the moon
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Alphanautics]
#7732152 - 12/08/07 07:36 AM (16 years, 3 months ago) |
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The temperature of boiling water/steam at a certain pressure is fixed.
If you are under 2000 ft elevation you don't need to use any correction.
Pressure - Temperature 0 psi - 100ºC (212ºF) 5 psi - 104ºC (220ºF) 10 psi - 113ºC (235ºF) 15 psi - 121ºC (250ºF)
-FF
Edited by fastfred (12/08/07 07:50 AM)
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Nibin
Getting there
Registered: 11/29/05
Posts: 4,480
Last seen: 10 years, 10 months
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Re: Rig up a thermometer for my PC through the blast valve? [Re: fastfred]
#7732342 - 12/08/07 09:16 AM (16 years, 3 months ago) |
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To be exactly correct you have to substract the difference in antmosferic pressure between sea level (14.7 PSI) and the atmosferic pressure you are at. Remember that the actual pressure in your PC is the measure on the gauge PLUS the atmosferic pressure and it is that value that gives you the boiling point of water.
Everything will be standardized to 1 atmosphere of pressure, but as fastfred said, under 2000ft the difference is so small it is negligible
-------------------- Newcomers guide-----> For all things shroomy
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__Tennessee_Jed_
wood tick
Registered: 11/23/07
Posts: 47
Loc: 47.7396 deg lat.
Last seen: 13 years, 11 months
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Re: Rig up a thermometer for my PC through the blast valve? [Re: fastfred]
#7732446 - 12/08/07 09:58 AM (16 years, 3 months ago) |
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Quote:
fastfred said: The temperature of boiling water/steam at a certain pressure is fixed.
If you are under 2000 ft elevation you don't need to use any correction.
Pressure - Temperature 0 psi - 100ºC (212ºF) 5 psi - 104ºC (220ºF) 10 psi - 113ºC (235ºF) 15 psi - 121ºC (250ºF)
-FF
no need for a therm.
-------------------- Tennessee..Tennessee..there ain't no place I'd rather be...
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RogerRabbit
Bans for Pleasure
Registered: 03/26/03
Posts: 42,214
Loc: Seattle
Last seen: 1 year, 1 month
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Re: Rig up a thermometer for my PC through the blast valve? [Re: __Tennessee_Jed_]
#7732477 - 12/08/07 10:05 AM (16 years, 3 months ago) |
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Agreed, and the last thing you want to do with a pressure cooker is to disable the over-pressure relief plug, which means you have just armed a bomb in your kitchen.
If you allow a pressure cooker to vent steam for five minutes, and then build pressure, you will have 250F at 15 psi, provided you're at sea level. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
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Alphanautics
Goonmaster
Registered: 11/26/07
Posts: 103
Last seen: 4 years, 2 months
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Re: Rig up a thermometer for my PC through the blast valve? [Re: RogerRabbit]
#7734486 - 12/08/07 07:39 PM (16 years, 3 months ago) |
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thats true.. but hey, why exactly does altitude factor in? PV= nRT, right?? or is it because n (number of moles) would be lower because the air is "thinner"..?
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RRVideo
Stranger
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Alphanautics]
#7734527 - 12/08/07 07:54 PM (16 years, 3 months ago) |
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It's not so much because the air is thinner per se, but that at a higher elevation it weighs less. The weight of the air above causes pressure, and the water must overcome this pressure in order to change state. At sea level, the weight of the air causes a pressure of just under 15 psi. That's what we live in. When you heat your pressure cooker to 15 psi, that's 15 above the ambient pressure. If you have a lower ambient pressure against the water, it will change state at a lower temperature. That's why when your PC reads 15 psi in Denver or Johannesburg, it isn't as hot as the same PC in Seattle or London would be. RR
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Nibin
Getting there
Registered: 11/29/05
Posts: 4,480
Last seen: 10 years, 10 months
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Alphanautics]
#7734660 - 12/08/07 08:39 PM (16 years, 3 months ago) |
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Quote:
Alphanautics said: thats true.. but hey, why exactly does altitude factor in? PV= nRT, right?? or is it because n (number of moles) would be lower because the air is "thinner"..?
Height factors in because pressure is equal to:
P = F/A in which F is the normal force made by the column of air above you and that amount of force depends on your altitude
-------------------- Newcomers guide-----> For all things shroomy
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Alphanautics
Goonmaster
Registered: 11/26/07
Posts: 103
Last seen: 4 years, 2 months
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Nibin]
#7803182 - 12/27/07 08:23 AM (16 years, 3 months ago) |
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Ok, that makes sense RR and nibin... so would you reccomend a surface-contact type thermometer on the side of the pc? i just want to know what temp my PC boils at with 5 10 and 15 psi in addition to the ambient pressure.. im at about 7200 feet above sea level if anyone wants to help me figure it out.. im having a hard time finding anything. I took this meteorology class but i don't know how to convert mmHG or hPa into psi (doesn't it fluctuate anyways?) to help figure out just what my ambient pressure is..
anyways.. thanks
Edited by Alphanautics (12/27/07 08:29 AM)
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RogerRabbit
Bans for Pleasure
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Re: Rig up a thermometer for my PC through the blast valve? [Re: Alphanautics]
#7803226 - 12/27/07 08:41 AM (16 years, 3 months ago) |
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http://wiki.answers.com/Q/How_does_the_elevation_and_air_pressure_affect_the_boiling_point_of_water
I recommend doubling cooking times at your elevation. For rye grains, I'd pc at 15 psi for 2 full hours. For pf jars, I'd use an hour to 90 minutes.
Don't modify the PC. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
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