Several valid points have been made about this idea, and as I as always welcome constructive advice, I'm submitting a revised version of this idea, implementing some of the suggested improvements. The original version is further down, so you can see the changes I've made. Let me know what you think!
Revised Edition:
This idea is for a hard-sided travel cooler, just big enough to hold a few drinks and some snacks on ice. Like many existing coolers, mine uses a double-wall construction, with a permanently sealed vacuum between the outer walls. This is for insulation. Now for the unique part: There are 2 airtight seals, one inner seal, and one outer seal. Once the lid is in place and the inner seal is secured, the air between the 2 seals is then removed using a hand pump, creating a vacuum seal to keep the lid on nice and tight. A torque-wrench-style pump prevents the lid from being over-tightened, so you don't have to worry about pumping too hard and breaking anything.
Original:
This idea is for a travel cooler, just big enough to hold a few drinks and some snacks on ice, that has a hand-crank vacuum pump, which is used to evacuate the air and create a strong seal, to prevent leaks and spills. A simple valve in the lid would allow air back in for pressure equalization, thus allowing the lid to be easily removed. I've seen vacuum pumps for food containers, but none that are hand-powered, and none for coolers or thermoses.-- 21 Quest, May 06 2009 http://en.wikipedia.org/wiki/Thermos [zeno, May 07 2009] and this http://images.googl...hermosfles&aq=f&oq=They are sealed nice and tight for easy transport. I think that's what it is [Loonquawl] [zeno, May 07 2009] Vacuum keeping lid extremly tight http://www.foodnews...s/einmachglas_k.jpgThe seal is the release, too, pulling it sideways lets air in. [loonquawl, May 08 2009] Baked in 1892. [link] The commercial market appears wide open though.
Biomimicry is a wonderful thing. Mother nature has been kicking our oh so innovative asses for billions upon billions of years.-- 2 fries shy of a happy meal, May 07 2009 Not quite what I had in mind, 2 fries. Most hard-sided coolers these days are double-walled with a vacuum between the walls for insulation. This idea is for the air in the storage chamber to be evacuated to keep the contents inside if the cooler is tilted or knocked over.-- 21 Quest, May 07 2009 This could be made very simple like the vacuvin.+-- zeno, May 07 2009 won't this partially freeze-dry your food/drink?-- xaviergisz, May 07 2009 Not if they're individually packaged.-- 21 Quest, May 07 2009 I have trouble visualizing the thing: Say i have a piece of meat and a small bottle of milk, and i'd like to keep both cool. So i put them into a shell/bag(?) and evacuate the air with pump. Now what makes them keep cool?-- loonquawl, May 07 2009 If they're individually packed (at atmospheric pressure), the packaging will expand and rupture in a vacuum.
I think the idea here is using a vacuum to reduce the transmission of heat. Apart from the problems of: a) packaging rupture, b) unpackaged food freeze-drying, and c) the evaporated liquid from the food eventually increasing the pressure within the container, there is also the problem that air is already a relatively good insulator and the vacuum won't prevent the majority of the heat being transmitted by conduction from the container wall to the food.-- xaviergisz, May 07 2009 i agree [xaviergisz], but i think there is more to this idea, as [21 Quest] wrote // This idea is for the air in the storage chamber to be evacuated to keep the contents inside if the cooler is tilted or knocked over. // So it cannot be a simple thermos-box that gets evacuated on the inside.-- loonquawl, May 07 2009 Listen guys and gals, The idea says clearly: vacuum used to prevent leaks and spills, it says so twice. [21 Quest] then said in his anno, and I quote: //This idea is for the air in the storage chamber to be evacuated to keep the contents inside if the cooler is tilted or knocked over.\\
//I think the idea here is using a vacuum to reduce the transmission of heat.\\ There is no reference to any part of the content of this statement in the idea, so no, that is not what the idea is about.
[Loonquawl] and [Xaviergisz], if you two would be in a relationship there would be constant shouting of YOU NEVER LISTEN! Sound familiar?
Oh and just in case: if you put something in a vacuum, it does not freeze.-- zeno, May 07 2009 Zeno, you couldn't have said it better. The idea is to pump out the air, not the heat. You guys do know the difference between air and heat, right? The purpose of the vacuum is not to facilitate cooling. The cooling is performed by the ice in the cooler, which I mentioned in the first sentence of the post. If you've ever used a cooler for travelling, camping, or a tailgate party, then you know that the ice eventually melts and becomes liquid. The vacuum helps trap that liquid inside the cooler so it doesn't leak out.-- 21 Quest, May 07 2009 If they're individually packaged, they won't leak or spill. Unless they're in a vacuum.-- tatterdemalion, May 07 2009 But the ice *will* leak when it melts.-- 21 Quest, May 07 2009 But according to zeno, you can't have ice in a vacuum.-- tatterdemalion, May 07 2009 I think that what Zeno meant is that putting something in a vacuum will not *cause* it to freeze. For instance, if you put a bottle of liquid water into a vacuum chamber, it would remain liquid. On the other hand, if you put an ice cube into a vacuum chamber, it would remain frozen unless you did something to raise the temperature inside the chamber. Putting ice in the chamber would, of course, lower the temperature by absorbing the heat. The point of doing this with a cooler, of course, is that the chamber is insulated to keep external heat out. Or in...-- 21 Quest, May 07 2009 How do you remove the air but leave the heat in place?-- tatterdemalion, May 07 2009 Who cares? It keeps your stuff cold. I'm not a physics professor, look it up.-- 21 Quest, May 07 2009 ok, I admit I read something into the idea that wasn't there, my apologies.
The idea is to use a vacuum as a means of securely holding a lid onto a container.
I think my other comments are still valid despite my misunderstanding the purpose of the vacuum.-- xaviergisz, May 07 2009 [+] Bun, but only if the lid is sealed against the container via two airtight seals (one inner seal and one outer seal), and only the space between seals is vacuumed out; that way, the contents of the container remain at atmospheric pressure.
Vacuuming out the *entire* container would have a variety of drawbacks: 1) It would take an excessive time to get a decent vacuum in a large container with a hand pump. 2) Everything within would need to be individually packaged in minimally expanding pressure-tight containers, to avoid freeze drying. 3) If you're going to go to the trouble of putting everything in pressure tight containers... nothing can spill, so there's no point in making the outer box spillproof. 4) If any liquid *does* escape it's container into the box, it would (eventually) evaporate and reduce the vacuum, allowing the lid to fall off, and the liquid to spill.-- goldbb, May 07 2009 Granted :-)
Now, on to your other, perfectly valid points:
a) Package rupture: Put the stuff in Zip-Lok bags, but squeeze out the extra air before sealing the bag. I always do that anyway to keep the food fresh.
b) Unpackaged food freeze-drying: Don't put unpackaged food in the cooler. Bag it first, using the method described in (a).
c) Evaporated liquid increasing pressure within the container: problem solved with a one-way pressure-relief valve.
Vacuum has been recognized as a good insulator at least since 1892. See the link posted by 2 fries. Most thermoses and hard-sided coolers are made using double-wall construction, with a vacuum layer between the 2 walls, and nothing between to transmit heat from one wall to the other, leaving radiation as the only form of heat penetration. My cooler uses that same double-wall construction, with a vacuum layer bwteen the walls for insulation, and a vacuum in the storage chamber for a more secure seal, which helps in 2 ways:
1) With the lid on airtight, melted ice can't leak out and make a mess.
2) With an airtight seal, warm outside air cannot get in, which means your stuff stays cooler longer.
Goldbb, you posted your anno while I was typing mine. In response: Your idea for the double seal is a better idea, I admit. I didn't think of that, and will amend the post. However, I was concerned with ice melt leaking. I always keep drinks and other liquids in spill-proof containers anyway to avoid having to clean out the cooler after each use, and to prevent everything else from getting sticky. I recommend it anyway, because once it gets mixed with all the melt water in the cooler it'll be so diluted as to be undesirable for consumption, anyway.-- 21 Quest, May 07 2009 There seems to be a different breed of cooler in germany - i never even heard of the problem you solved. The coolers i know are a hard-shell box (the shell incorporates some kind of insulation, depending on the price this is anything from air over foam to vacuum)
the box has a compartment for putting ice/cooling packs, mostly in the lid, always watertight, so no spill.
the lid itself has a super simple seal relying on the lid being pressed onto the box - the pressing is done by two small levers at two sides.
I realize now i got your solution from the start. Never having seen the problem it sounded weird, though.
See link for implementation of the initial one-seal-idea-- loonquawl, May 08 2009 random, halfbakery