Vacuum Chamber

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sofiadragon1979
 
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Vacuum Chamber

Post by sofiadragon1979 »

I am working on a bread box that I want to be pressurized w/ a vacuum so that the bread will be kept fresh. I am wanting to keep the system w/ an arduino & a vacuum pump & a pressure sensor. Can anyone tell me if this is a feasable idea.

thefatmoop
 
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Re: Vacuum Chamber

Post by thefatmoop »

if you like dry bread

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adafruit_support_bill
 
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Re: Vacuum Chamber

Post by adafruit_support_bill »

Haven't heard of this technique for keeping bread. But from a controls point of view, it is quite feasible to control a vacuum pump with an Arduino. The first thing you need to do is figure out what pressure range you need to achieve and select an appropriate pressure sensor. I've had good results with the Freescale MPX series. But there are many others out there.

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stinkbutt
 
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Re: Vacuum Chamber

Post by stinkbutt »

This seems like it'd do the opposite of keeping the bread fresh. "Fresh" bread has moisture left in the bread. Pulling a vacuum will just boil away your water. You're going to dry it the heck out, which is what most people refer to as "stale" bread.

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sofiadragon1979
 
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Re: Vacuum Chamber

Post by sofiadragon1979 »

Drawing a vacuum doesn't mean that it will dry out the bread @ all, I vacuum seal meat all the time, & it doesn't get dry @ all, I've also vacuum sealed tons of things including slices of bread & it hasn't dried out, so I doubt that a loaf will dry out.

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easternstargeek
 
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Re: Vacuum Chamber

Post by easternstargeek »

Some food, er, bread for thought:
http://www.ehow.com/how-does_4571444_wh ... stale.html

On the other hand, if you really love vanilla wafers or snacky crackerish things, your vacuum chamber would be a real winner!

Build it anyway- you'll think of a use for it. Degassing potting compound, perhaps?

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westfw
 
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Re: Vacuum Chamber

Post by westfw »

(a vacuum-tight containing the size of a breadbox is a significant mechanical engineering/construction challenge.)

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sofiadragon1979
 
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Re: Vacuum Chamber

Post by sofiadragon1979 »

I was anticipating that, that's why I was getting a little feedback on here on if it was a feasible idea or not.

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easternstargeek
 
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Re: Vacuum Chamber

Post by easternstargeek »

Indeed- the pressure-vessel design will not be trivial.

A typical roughing pump will pull a vacuum that will subject the outside vessel surface to a pressure of about 12 PSI. Think about that- 12 pounds of force acting perpendicular to every square inch of surface! That's more than enough to collapse a steel 55 gallon drum.

For maximum nerd cred, see if you can get your hands on a second-hand vacuum bell jar and base (don't forget to pick up some stopcock grease, too!). Be careful, however- these are made of glass, and if they have been beat-up or nicked badly enough, they could fail and implode. NEVER use a cracked jar- even a small crack. Wear your safety glasses and stand far away during the maiden voyage, just in case.

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sofiadragon1979
 
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Re: Vacuum Chamber

Post by sofiadragon1979 »

Initially I was thinking about using acrylic then I remembered an episode of Time Warp that I saw a few days ago, they were using a negative vacuum w/ rapid temp changes & just how fast the decompression happened I loved it, but I then thought about glass. So high strength glass would be a better idea?

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westfw
 
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Re: Vacuum Chamber

Post by westfw »

If you want to keep bread fresh, I'd investigate ways to remove oxygen from an otherwise atmospheric-pressure container, probably by flushing with an inert gas like nitrogen or CO2. Operating a couple of high-pressure valves and dealing with a certified tank of gas seems like it would be safer and easier than dealing with a cubic foot of vacuum.

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adafruit_support_bill
 
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Re: Vacuum Chamber

Post by adafruit_support_bill »

I've also vacuum sealed tons of things including slices of bread & it hasn't dried out, so I doubt that a loaf will dry out.
Vacuum sealing is not the same as storing in a vacuum chamber. When you vacuum seal a slice of bread, a mild vacuum evacuates the excess air from the bag. But since the bag itself is flexible, once you seal it, the pressure inside the bag is the same as the normal atmospheric pressure outside.

The reason vacuum sealing preserves freshness is because you have removed all that excess volume of oxygen from the bag. Not because the bread is in a vacuum.

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Franklin97355
 
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Re: Vacuum Chamber

Post by Franklin97355 »

Remember freeze drying is done in a vacuum.

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philba
 
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Re: Vacuum Chamber

Post by philba »

What are you trying to do? Maintain fresh bread or do something interesting with a vacuum?

Fresh bread requires several things - humidity, oxygen removal and suppressing mold growth (longer term storage). No vacuum is required.

Interesting food related things to do with a vacuum - food dryer, juice concentrator, seal-a-meal stuff. Plenty of interesting computing to be done there.

flink
 
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Re: Vacuum Chamber

Post by flink »

sofiadragon1979 wrote:I am working on a bread box that I want to be pressurized w/ a vacuum so that the bread will be kept fresh. I am wanting to keep the system w/ an arduino & a vacuum pump & a pressure sensor. Can anyone tell me if this is a feasable idea.
You're in the wrong forum to ask about vacuum projects. Try a DIY woodworking forum like Wood Net or a skateboard forum with a lot of DIYer's making boards.

Wood workers and skateboard makers frequently use vacuum systems to assist in securing wood laminations (bent and straight) and in the veneer gluing process.

Cruise over to Joe Woodworker's for all you want to know about vacuum systems. http://www.joewoodworker.com/

BTW, most vacuum systems are purely mechanical, being controlled via pressure valves. No electronics required ;-)

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