Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
BCM
User Panel

Posted: 11/14/2009 2:55:12 AM EDT
If I have 4 round pipes with a OD of 7" arranged in a square, sides touching,  how big of a ID round pipe would I need for all 4 to fit inside of ?
Considering all pipes are perfectly round.
Link Posted: 11/14/2009 3:04:45 AM EDT
[#1]
14"

I think that's wrong...
Link Posted: 11/14/2009 3:07:33 AM EDT
[#2]
Quoted:
14"

I think that's wrong...


I am geometry dumb,
But I know it would be more than 14"
Link Posted: 11/14/2009 3:17:31 AM EDT
[#3]
2.414 x 7 = 16.898





Link Posted: 11/14/2009 3:27:53 AM EDT
[#4]











7/2" + 7/2" = 7"

Sqrt(72+72) = 9.8995"



ID = 16.8995"







 
Link Posted: 11/14/2009 3:51:56 AM EDT
[#5]





Quoted:



2.414 x 7 = 16.898





I would have beaten you to it if I hadn't been sidetracked thinking about using a larger number of circles than four.


But then, I still win because I have a sucky MSPaint included in my explanation.





ETA: And because your answer is ever so slightly too small.






 
Link Posted: 11/14/2009 4:52:37 AM EDT
[#6]
14

WTF crazy ass math have we got running around here... or have I failed the reading comprehension part?
Link Posted: 11/14/2009 5:02:27 AM EDT
[#7]



Quoted:


14



WTF crazy ass math have we got running around here... or have I failed the reading comprehension part?


reading comprehension, you fail at it.



he wants to fit 4 pipes stacked squarely, into a large round pipe, and what diameter would he need, I guessed 18 off the top of my head but i overshot by a inch or so




 
Link Posted: 11/14/2009 5:06:11 AM EDT
[#8]
Quoted:

Quoted:
14

WTF crazy ass math have we got running around here... or have I failed the reading comprehension part?

reading comprehension, you fail at it.

he wants to fit 4 pipes stacked squarely, into a large round pipe, and what diameter would he need, I guessed 18 off the top of my head but i overshot by a inch or so
 


Roger fucking That.  Forgot about the gap in the middle... didn't pay attention to the msPaint post.  

da-da-damn, I'm such a rock, sometimes most times.
Link Posted: 11/14/2009 5:09:00 AM EDT
[#9]
Quoted:
14

WTF crazy ass math have we got running around here... or have I failed the reading comprehension part?



You failed the comprehension part.  4 equal sized pipes touching each other in a square config. will not touch at the center of the cluster they create.  Thus the circle that inscribes the square arrangment must be larger than double the diameters of a pipe.

Actually 4 pipes of the same size will never be inscribed by a circle equal to twice one pipes diameter.  If you compress the square config. so two pipes are touching at the center of the cluster then you have pushed the other corners away and have increased the size of the circle that will contain them all.
Link Posted: 11/14/2009 9:04:36 AM EDT
[#10]
Thanks guys.
Link Posted: 11/14/2009 9:20:10 AM EDT
[#11]
About 16.94 in
Link Posted: 11/14/2009 9:27:21 AM EDT
[#12]
Nevermind.
Link Posted: 11/14/2009 9:29:53 AM EDT
[#13]
Quoted:
http://media.ar15.com/media/viewFile.html?i=14230

7/2" + 7/2" = 7"
Sqrt(72+72) = 9.8995"

ID = 16.8995"
 


You were right except you left off 1 radius in the upper right, so you need another 7" for a total of 23.98".
Link Posted: 11/14/2009 9:31:49 AM EDT
[#14]
Quoted:
BS
If the inside pipes are 7" OD, the ID of the large pipe will have to be 14".


RIF?

ar-jedi
Link Posted: 11/14/2009 9:32:46 AM EDT
[#15]
Nevermind... you'd get two in there, but not the remaining two.  Early morning brain glitch.
Link Posted: 11/14/2009 9:33:23 AM EDT
[#16]
see http://www2.stetson.edu/~efriedma/cirincir/



http://hydra.nat.uni-magdeburg.de/packing/cci/cci4.html




the answer is the ratio above (2.414) x the diameter of one of the inner circles, so 2.4142 x 7 = 16.898"

ar-jedi


ps:
there is an entire branch of math related to this problem, and lots of websites to learn from:

e.g.


Link Posted: 11/14/2009 9:34:09 AM EDT
[#17]
The next step is to identify a standard pipe size which is "just larger" than the 16.9 inch calculated figure.

Edit to Add:

Sched 40 Pipe 18" Nominal has a 16.874 ID
Sched 40 Pipe 20" Nominal has a 18.814 ID

Sched 80 Pipe 18" Nominal has a 16.126 ID
Sched 80 Pipe 20" Nominal has a 17.938 ID
Link Posted: 11/14/2009 9:39:00 AM EDT
[#18]





Quoted:





Quoted:


http://media.ar15.com/media/viewFile.html?i=14230





7/2" + 7/2" = 7"


Sqrt(72+72) = 9.8995"





ID = 16.8995"


 






You were right except you left off 1 radius in the upper right, so you need another 7" for a total of 23.98".
7" is not the radius. It is 3.5".



Radius + Radius + Hypotenuse = ID



max is correct.
 
Link Posted: 11/14/2009 9:44:08 AM EDT
[#19]
Quoted:

Quoted:
Quoted:
http://media.ar15.com/media/viewFile.html?i=14230

7/2" + 7/2" = 7"
Sqrt(72+72) = 9.8995"

ID = 16.8995"
 


You were right except you left off 1 radius in the upper right, so you need another 7" for a total of 23.98".
7" is not the radius. It is 3.5".

Radius + Radius + Hypotenuse = ID

max is correct.

 


You and max are right.  I thought he was adding a single radius when it was really 2 radii.
Link Posted: 11/14/2009 9:46:13 AM EDT
[#20]



Quoted:



Quoted:


Quoted:


Quoted:

http://media.ar15.com/media/viewFile.html?i=14230



7/2" + 7/2" = 7"

Sqrt(72+72) = 9.8995"



ID = 16.8995"

 
You were right except you left off 1 radius in the upper right, so you need another 7" for a total of 23.98".
7" is not the radius. It is 3.5".



Radius + Radius + Hypotenuse = ID



max is correct.

 
You and max are right.  I thought he was adding a single radius when it was really 2 radii.
Check. Sorry if I came off a little cranky; I just woke up, I saw this, and thought 'school system'...






 
Link Posted: 11/14/2009 12:52:29 PM EDT
[#21]



Quoted:


see http://www2.stetson.edu/~efriedma/cirincir/



http://www2.stetson.edu/~efriedma/cirincir/ccc4.gif



http://hydra.nat.uni-magdeburg.de/packing/cci/cci4.html



http://hydra.nat.uni-magdeburg.de/packing/cci/pic/cci4.gif





the answer is the ratio above (2.414) x the diameter of one of the inner circles, so 2.4142 x 7 = 16.898"



ar-jedi





ps:

there is an entire branch of math related to this problem, and lots of websites to learn from:



e.g.

http://hydra.nat.uni-magdeburg.de/packing/cci/pic/d1.gif





Cool pics!




 
Close Join Our Mail List to Stay Up To Date! Win a FREE Membership!

Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!

You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.


By signing up you agree to our User Agreement. *Must have a registered ARFCOM account to win.
Top Top