
New closure allows camping mattress to be inflated in seconds - prawn
http://www.kickstarter.com/projects/1484284472/windcatcher-inflates-in-seconds-with-no-power-or-p
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baudehlo
I'm afraid there's already a matress that does this. It's from exped, I own
one and it's awesome, and better implemented than this because you're only
inflating a small pump sack, and can use it to build pressure in the mattress.

Here's a video:
[http://www.exped.com/exped/web/exped_homepage_na.nsf/b43popu...](http://www.exped.com/exped/web/exped_homepage_na.nsf/b43popup4/2A9E7D03BE26A60DC125767E00705EAE?Opendocument)

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TylerE
That looks much slower, more complicated, and more expensive.

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baudehlo
It is more expensive but only because it has an R value of 8.0 (the
Kickstarter one has an R value of 1.0, which means it's not going to give you
any protection from the cold ground whatsoever - even a self-inflating pad
gives you more protection than that). You'd be amazed how much difference
higher R values make on the quality of rest you get while camping.

Is it slower? Maybe, but I inflate mine in two or three inflations of the bag,
and that takes me around 60 seconds - it's really not a long time in the big
scheme of things - it takes a lot longer to get the tent erected (although
that's down to about 5 minutes now). The problem is you can't inflate a high
R-value pad without pressure - the reason his inflates so fast is there is no
insulation, no down, no pockets, so the air can just go right in. But then so
does the cold.

Anyway all I was saying is this isn't a new technique - there's a mattress you
can buy today from any MEC/REI that uses this technique.

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jsherry
Whereas your first comment came off as a bit pithy, this was a really
informative one. Thank you for the lesson on r-value and its importance. Not
an avid camper, but I sometimes do overnights in the cold and today I learned
something important about air pad insulation. Thanks again.

Per REI's page on the topic, here's what they have to say about R-value:
"Insulation is measured according to its capacity to resist (that's the "R")
heat flow. The higher a pad's R-value, the better you can expect it to
insulate you from cold surfaces. The R-values shown on REI.com product pages
are provided by the manufacturers and range from 1.0 (minimally insulated) to
9.5 (well insulated). Thicker pads generally offer higher R-values."

Source: [http://www.rei.com/learn/expert-advice/right-sleeping-
pad.ht...](http://www.rei.com/learn/expert-advice/right-sleeping-pad.html)

~~~
larrydag
I looks like a wool blanket could help (R value around 4)
<http://en.wikipedia.org/wiki/Wool_insulation>

~~~
baudehlo
The problem is that adds to your weight. Not important if you're car camping,
but important for hiking.

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adaml_623
These guys have taken the same physical phenomena used in the newish Dyson
fans and hand dryers and found a radically different way to use it.

This looks as simple as a paper clip and I think in years to come many people
will wonder why they didn't think of it first. True genius

EDIT: I stand corrected by HN. There are number of bags that use similar
techniques and apparently airplane evacuation slides inflate using that
physical phenomena as well.

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UnoriginalGuy
Speaking of which, I wonder if they'll need to deal with patents. From what I
understand Dyson has that technology wrapped up tight.

PS - Dyson's fans are also terrible. Great concept, poorly executed. They
wanted them to be sleek, so they used tiny motors which are LOUD making
Dyson's Air Multiplier far louder than other fans WITH blades.

PPS - <http://www.youtube.com/watch?v=fVbEE0Qe4BQ>

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robomartin
I haven't (and will not) invest any time doing the numbers but, a quick think
about the Dyson fans leads me to conclude the whole thing is a big marketing
scam. Kudos for pulling it off, but the thing ain't magic.

For starters, it has blades. It definitely has blades. They are simply
concealed. It's like saying my computer has no fans when the fans are not
visible from the outside. Nonsense.

Second, it takes a certain amount of power to accelerate a mass of air to a
given speed. That does not change magically because the thing has a Dyson
sticker on it. The most efficient way to accelerate a mass of air is, wait for
it, a properly designed fan. It am pretty certain the Dyson contraption is
actually much less efficient than a properly designed plain fan which produces
the same airflow. It absolutely could not be more efficient, no way. Nowhere
in conventional physics do you get more --of anything-- than you are entitled
to.

In fact, the larger the fan the more efficiently it can accelerate a mass of
air. Because the Dyson fans are constrained by the small space of the base
they have to use screaming little fans to push against the back-pressure
produced by the path the air has to follow.

Maybe not as sexy, but a really well designed fan with optimized airfoils and
balanced rotor IS magical in the sense that it can be so much better than the
stamped metal contraptions one usually finds at the store. I have seen fans
like that come-up here and there but they are rare.

I did a project many years ago where we had to design and optimize an
efficient cooling system for a 1500 Watt LED array. We ultimately ended-up
going with a hybrid fluid/air system. However, for the bulk of the project we
tried to make an air-only approach work because it was deemed simpler and
easier to manufacture. I learned a lot from running tons and tons of FEA fluid
and thermal simulations as making a number of prototypes. There is no free
lunch (AKA: Conservation of Energy).

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darkmighty
I haven't seen any checks on this, but I suspect the Dyson can probably move
more air than a regular fan. It probably isn't more raw energy-efficient, but
it _can_ be more comfort energy-efficient (more comfort for the same energy),
because their principle makes sense -- if you use a regular fan, you air speed
is going to be dictated by the blade speed, while the amount of air depends on
the area. With the dyson, they can get a much greater area, which dictates
confort, with the same air speed, because they've distributed the stream along
this circle, and it picks up more air as it goes (and loses speed).

My point is, it may be poorly executed, but in principle it sounds nice, not
even taking into account you don't actually have an exposed blade to worry
about. It's not a scam.

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robomartin
And I am arguing it is complete hogwash.

If a ring of air magically propels a lot more air around it, do you think a
fan of the same diameter might just compel the same air molecules to follow
suit?

> if you use a regular fan, you air speed is going to be dictated by the blade
> speed

On the Dyson air speed IS dictated by blade speed. They have a damn fan at the
base pushing air through the system and they use that air to accelerate some
more air around it. Again, I am not going to waste my time doing any math. My
educated guess is that the efficiency, when compared to a properly designed
fan of the same diameter is atrocious.

One other point, air speed coming out of a fan is not solely dependent on
blade speed. Blade shape, diameter, angle of attack, duct length and even
airfoil come into play.

You also have centrifugal, fans which operate under slightly different
principles and can deliver airflow at greater pressure than axial fans.

More importantly, if you are trying to cool something air speed isn't always
the most important criteria. The volume of air moved per unit time is
extremely important. It has to be matched to the thermodynamics of the heat
exchange that will happen with whatever it is you want to cool Delivering air
faster and with greater volume than necessary is a waste of energy.

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jgrahamc
The Kickstarter itself says: "You're supporting an entirely new type of
technology that has the potential to inspire new ideas and future innovative
products."

No, you are not. Exploiting the pressure difference like this for inflation is
not new by a long shot. Just pop down to REI:
<http://www.rei.com/product/829645/exped-schnozzel-pumpbag>

Edit: read rest of replies below for clarification.

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jjoonathan
There are also entirely passive self-inflating mattresses out there. They're
filled with (solid-gas) foam that expands when you open the valve. Close the
valve and it's ready to go. You store the energy for pumping when you deflate
the mattress by rolling it back up. It's much easier to provide energy by
sitting on something than by blowing into it :)

I don't know the brand name, only that they were old and worn by the time I
was using them as a kid. They must have been commercially available around
1990.

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CanSpice
You're probably thinking of Therm-a-Rest mattresses. According to Wikipedia,
they've been around since the early 1970s.

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jjoonathan
Yes! That's the brand name. I remember the logo!

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Zmetta
The valve is based on the Venturi effect. The fluid flow through a
constriction lowers the pressure at the constriction point. An inlet at the
low pressure point will allow addition fluid at atmospheric pressure to enter
through the inlet in the constriction thus adding to the total fluid through
the outlet. Pretty clever use of fluid dynamics!

~~~
tlrobinson
Avalanche airbags use the same principle to inflate larger than the volume of
compressed air in their canisters.

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aaronsnoswell
In one of my first year physics course they showed a great demo based on this
principle. A student was challenged to inflate a _huge_ bag as much as
possible. They always did miserably, only filling the bag to about 1/8th. The
lecturer then used this technique to fill the entire bag in one hit. A great
demo that I'll never forget.

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pge
This is a great demo - it's often done at kids' science museums as well, if
they have an instructional area. Particularly with kids' tiny lungs, they can
only fill a fraction of the bag, then when they do it this way, they fill a
bag bigger than themselves. It's definitely memorable.

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jonahx
I love software innovation, but somehow it always impresses me more to see
real world mechanical innovation like this, true old-school inventor
entrepreneurship. Seems like a legitimately great idea.

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smtddr
It should impress you more!

For all the talk of "changing the world" that comes in the software start-up
scene, it's the physical inventions[1] that have more obvious & immediate
impact on the world - and by "world", I really mean developing countries
instead of our first-world problems(annoyances really). These fast-
inflating/deflating mattresses would be very helpful in those countries.

1\. <http://vimeo.com/53588182>

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cjfont
Nice concept, but I'm wondering how inflating a mattress in this manner will
allow you to achieve the pressure needed to support your weight.

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drharris
By laying on it, you're compressing what's in there, and it pushes back on
you. There's no need to ever inflate a mattress like a bicycle tire.

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eli
My back hurts just thinking about sleeping on an underinflated mattress. More
power to you if it works for you.

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kaiuhl
The opposite is actually true. I sleep a month a year on a camping pad, and
it's well known among avid backpackers that air pads like that shown in the OP
are most comfortable when under inflated enough to keep your hips just above
the ground.

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jamii
I don't really see the appeal for mattresses. I have a very comfy foam/air
mattress just about fits in my pocket and inflates faster than their demo.

My tent, on the other hand, has an inflatable beam that takes a good minute to
blow up...

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aetimmes
What brand of air mattress do you have, if you don't mind my asking?

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jamii
I think it's this one - [http://www.multimat.uk.com/store/products/superlite-
compact-...](http://www.multimat.uk.com/store/products/superlite-compact-25)

Its pretty easy to get it down to about 25x10x3cm. I travelled with it for
three years without any punctures.

This is the tent - [http://www.backcountry.com/nemo-equipment-
inc.-moto-1p-super...](http://www.backcountry.com/nemo-equipment-
inc.-moto-1p-superbivy-1-person-3-season)

~~~
jebeng
Totally different product really...

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devmach
Ok, i'll play devil's advocate : Windcatcher works as same principle as
evacuation slides on planes and even if it's about physics i think it's
somehow ( design ? ) patented.

So, what about patents ? Is there any patent that product violate and may
cause later any problem ?

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aredington
Say it's the exact same mechanism as evacuation slides.

Patents in the U.S. since 1995 have had a term of 20 years, prior to 1995 it
was a term of 17 years.

The slides were initially patented in 1956. In 1956 the U.S. patent term was
17 years; those patents expired in 1973.

But, let's suppose some advances were made and the specific valving mechanism
was patented later. It would have had to have been invented and patented some
time after 1995 to still be covered by a patent.

If it were patented any earlier, its term will have expired and the idea is
now in the public domain, which means anyone can use the idea without paying
anything.

~~~
devmach
Thanks for the clarification.

They should really add some info about patents and prior art on kickstarter
page. And i hope , just to be sure , they applied for a patent their design.

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yitchelle
It is interesting as what other application this would have?

If I could replace my mouth (the source of the wind) with an electric fan,
what else can I do with this?

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JulianMorrison
Or with actual wind. Scale it up, use it for rapid construction of emergency
housing? An inflatable former can be covered with concrete quickly and then
deflated.

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gnosis
How large would it need to be scaled in order to generate useful amounts of
power by sticking a wind turbine on it?

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bazzargh
The stuff about inflating with your mouth is a bit of a straw man. If you
inflate say a Thermarest NeoAir or a Packraft you're more likely to use
something like an Instaflator now:

<https://www.youtube.com/watch?v=yJLVYfg88TE>

(Thermarest have their own variant on the bag inflator for the neoair - but
the principle's the same)

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nmcfarl
The backpacking mattresses are still inflated by mouth - I’m certainly not
carrying another 2 oz on my back for a week just to save a minute on
inflating. And neither are any of the folk I go into the backcountry with.

But this mattress is not aimed at us either - it weighs in at 24 oz with an R
value of 1!

So perhaps the Thermarests owned by people who’d buy this are currently being
inflated by Instaflators...

~~~
bazzargh
I did say 'like' an Instaflater - it's the mechanism I meant. The thermarest
pump sack doubles as a stuff sack, so it's not dead weight like the
Instaflater.

I'm a bike tourer, not a backpacker, so I tend to shave weight when I can drop
a pound not an ounce - carrying that isn't a big deal.

But yeah, 24oz and R 1 is pretty bad.

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marcamillion
I don't get all the negative, visceral reactions to this product.

Who cares if the physics/technology is "breakthrough"?

It's clear that this is being positioned as a suitable alternative to the
battery operated pumped up mattress. The ones sold in Walmart, Target, etc.

I own one of those, and they are a pain to deal with. This looks awesome.

Who cares if there are others out there already - that proves that the market
exists and the technology is feasible. My concern with this is, given that I
don't understand the technology behind it, and I have never seen it before -
is that it is too fanciful to work. i.e. is this another "Kickstarter fraud"?

The presence of existing products on the market that use similar technology is
surprisingly re-assuring.

If I were an avid camper, I would definitely buy this.

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joeld42
Ah, closures. Is there anything they can't do?

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bradleysmith
There's a problem I had solved. Ver' nice.

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bradleysmith
Downvoted for agreeing that this solves a problem? Not belly-aching, but that
was honest input.

I was happy to see someone build this; I've hated thermarest valves since I've
known them.

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prawn
Someone might have read your comment as "There's a problem I had already
solved" rather than "There's a problem I had, solved."

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3rd3
So how does this work?

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crb
Scroll down the Kickstarter page for a very readable explanation:

"The secret behind the Windcatcher's amazing speed of inflation is its ability
to leverage the awesome properties of air. Simply put, the two most important
properties are:

\- Fast moving air has lower air pressure than slow moving air

\- Air with higher pressure will be drawn to areas of lower pressure

When you blow into the Windcatcher you create a stream of fast moving, low
pressure air. Because it has a higher air pressure, the surrounding air is
sucked into the low pressure air stream. As a result, the air entering the
Windcatcher is at least 10 to 15 times greater than the air you expelled from
your lungs."

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unwind
I guess the final sentence is missing a "volume of", i.e. it should be
something like "As a result, *the volume of air entering the Windcatcher
[...]", right? I double-checked and this error is on the Kickstarter page,
it's not your quote.

Just mentioning it in case the project owners drop by. Cool project, by the
way!

~~~
drharris
I think they must mean the air itself is actually better quality than yours...
10 to 15 times greater.

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d0c5
Oh. I must be here to tell you that things that are inflated can do only one
thing next.. I spend half my life outdoors and even though 75D ripstop is more
than most, I fear entropy will eventually have its way. Btw I use a corrugated
egg box kind of thing.

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tlrobinson
Avalanche airbags use the same (or similar) phenomenon to inflate to a larger
volume than the compressed gas canister contains.

I thought it was the venturi effect, but maybe entrainment is more accurate.

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alan
I'm more interested in this "one-way valve" they're talking about. While they
seem to talk mostly about blowing, the valve seems to be the actual invention.

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kwamenum86
If this is their IP they should license the technology out to an established
company. If this isn't their IP they're kind of screwed anyway.

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tomrod
I like the concept. I'd be willing to contribute though if it deflated and
folded up small instead. I don't mind inflating an air mattress.

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alexvr
I hope they can patent this just so they're not ripped off by big generic
companies. It's a great idea.

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deckar01
It seemed like he had to blow pretty hard.

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rusbra
Pretty awesome idea... I'd probably use it for my guest when they sleep over
since i never go camping!

