# This Corkscrew Sucks!

Literally. It’s called “My Corkscrew Sucks” and it does… in the best way! Lots of people love to collect their old wine corks for keepsake, but regular wine corks damage the cork in the process of opening. This design uses suction to pull out the cork, ensuring that it’s left perfectly in tact. It’s just as quick to use, safer, and takes less muscle!

Designer: Alan Kwok

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• Eddd222 says:

I’m afraid this will not work.

If you can create a complete vacuum above the cork, you would remove the 1 bar (0.1 N/mm2) of atsmospheric pressure.

A standard cork would have a diameter of approx 20 mm. This means the surface area of this cork is PI/4*20^2 = 314 mm^2

The resulting force would be 0.1 * 314 = 31.4 N
This will not be enough to open the bottle.

This might work with a champagne bottle, but generally these can be opened by hand.

• Alan Kwok says:

Thank you for your comment. However, I have some question to your calculation.

First,
Atmospheric pressure
~= 100kPA
for P=F/A,
= 100,000 N/m^2
= 100,000,000,000 N/mm^2
I do not understand why 1 bar is (0.1 N/mm^2)

Secondly,
given that the cork is 20mm diameter and 40mm tall,
total surface area of cork
= 2*PI*r*h + 2*PI*r^2
= 2*PI*r (h+r)
= 2 (3.14) (10) (40+10)
= 3,140 mm^2
I do not understand why the surface area is 314 mm^2. Anyway, I am not sure why the total surface area of the cork is considered.

The point is, if I can create a vacuum condition inside the corkscrew, pressure inside the corkscrew will be lower than that in the wine bottle, then the cork will move upward.

Please correct me if I am wrong. Thanks again.

• J.Eriksson says:

First question:
1 m^2 = 1000000 mm^2
100000N/1000000mm^2 = 0.1N/mm^2

Second question:
There is no such thing as negative pressure.
The vacuum is not sucking the cork, its the pressure in the bottle that want to push it out into the empty void. The pressure inside the bottle is equally distributed on the inside area and the force vectors are perpendicular to the surfaces of the area.

The cork being a cylinder would face a lower or no pressure on the top side with your device. The cylinder walls of the cork would in one case be sealed tight by the bottles neck and the pressure inside the bottle would only see the bottom area of the cork.

If the cork is longer then the bottle neck so that the cork cylinder walls are exposed; the force vectors would be perpendicular all around the cork cylinder walls and cancel each other out. The bottom area of the cork would again be the only thing that matters.

I doubt your device would work, but to make it work you must either use softer cork material, higher bottle pressure, lower friction cork or a different cork design.

• Eddd222 says:

Thank you mr Eriksson, couldn’t have done better myself.

• David says:

Hi Alan.
Thanks
David

• Alan Kwok says:

Hi David,

Thanks,
Alan

• Alan Kwok says:

Hi Eriksson,

This is a valuable engineering lesson to me, thank you for your explanation.