Bottoms of Diffuser Cans Are Concave - Why?

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neerajkumar Active Contributor Join Date: May 2011 Posts: 17 Good Answers: 1	Bottoms of Diffuser Cans Are Concave - Why? 01/11/2012 6:03 AM
	Is it for a reason or is it just like that?? I believe everything is for a reason...why the bottom of the diffuser (e.g. deodrant or any other spray can) is concave (sunk inside) not flat (may be, but majorly concave)??
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Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#1 Re: Bottoms of diffuser cans are concave;why? 01/11/2012 6:19 AM
	To withstand the internal pressure, a domed shape is best. It could be either convex or concave, but if convex the container would tip over. Hence concave. Q.E.D. __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
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SolarEagle Guru Join Date: Mar 2007 Location: by the beach in Florida Posts: 33392 Good Answers: 1817	#2 Re: Bottoms of diffuser cans are concave;why? 01/11/2012 6:34 AM
	In order to crimp the can, it's the cheapest way to do it to withstand pressure...Some are one piece and sort of corrugated concentrically, the more expensive products... __________________ All living things seek to control their own destiny....this is the purpose of life
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Steve of the North Guru Join Date: Dec 2010 Location: Up North Posts: 540 Good Answers: 30	#3 Re: Bottoms of Diffuser Cans Are Concave - Why? 01/11/2012 7:58 AM
	f=p/a. A concave or convex surface increases the internal surface area. More area reduces the stress [f]. Wine bottles employ the same principle. Or think of a stone arch above a door/opening. An arched header can withstand the forces coming from above much better than a typical door header. __________________ Steve of the North...since 1962.
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dkwarner Guru Join Date: May 2006 Location: Placerville, CA (38° 45N, 120° 47'W) Posts: 6215 Good Answers: 248	#6 In reply to #3 Re: Bottoms of Diffuser Cans Are Concave - Why? 01/12/2012 12:06 AM
	NO! Your formula is wrong! p=f/a, or f=p*a. Remember pressure is measured (in the US) in pounds per square inch. 'per' means divided by. Multiply the pressure by the area to get the force. Greater area INCREASES the force, and therefore the stress, for a given shape. It is the shape that is important, not the area. A thin flat sheet can support no perpendicular force (pressure) at the center and remain flat; it must have curvature. The curved shape is able to transmit the vertical forces to the can walls, while a flat surface would bulge out until it had sufficient curvature to transmit the force. Did you ever see a spoiled can of food? Now that I think about it, I haven't seen one in many years. 60 years ago it was a fairly common occurrence. I believe I mostly remember cans of sauerkraut... They would bulge due to the internal pressure of fermentation or other spoilage. __________________ Teaching is a great experience, but there is no better teacher than experience.
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Andy Germany Guru Join Date: Sep 2006 Location: Near Frankfurt am Main, Germany. 50.390866N, 8.884827E Posts: 17996 Good Answers: 200	#7 In reply to #6 Re: Bottoms of Diffuser Cans Are Concave - Why? 01/12/2012 7:39 AM
	GA I wanted to write the same, you beat me to it, well done! __________________ "What others say about you reveals more about them, than it does you." Anon.
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Tim in Mexico Guru Join Date: Jul 2008 Location: Anywhere I may be at the time Posts: 661 Good Answers: 16	#4 Re: Bottoms of Diffuser Cans Are Concave - Why? 01/11/2012 9:31 AM
	It could very well be flat, but the material would have to be much thicker to withstand the pressure, hence your shaving cream, deodorant, etc would be much more expensive
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neerajkumar Active Contributor Join Date: May 2011 Posts: 17 Good Answers: 1	#5 Re: Bottoms of Diffuser Cans Are Concave - Why? 01/11/2012 12:34 PM
	thank you all.....
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