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   I am looking for the easiest way to create an elliptical head for a 3D pressure vessel. The outside Dia. is 103" and, inside crown radius is 93.16", inside knuckle radius of 17.79" and a thickness of 0.500"  

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Castor63 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 23.Oct.2009 Status: Offline Points: 18	Topic: Elliptical Heads For Pressure Vessels Posted: 19.Feb.2010 at 02:31
	I am looking for the easiest way to create an elliptical head for a 3D pressure vessel. The outside Dia. is 103" and, inside crown radius is 93.16", inside knuckle radius of 17.79" and a thickness of 0.500"

CarlB Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 16.Oct.2009 Location: United States Status: Offline Points: 321	Posted: 19.Feb.2010 at 04:32
	Is this to be a 3d solid?

Castor63 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 23.Oct.2009 Status: Offline Points: 18	Posted: 19.Feb.2010 at 04:38
	yes I am making a solid 3D. I am thinking I can make an elipse going from 1 quadrant of the shell to the other then give it a hieght, trim it down and do a revolve. Would that make it the same as using the knuckle radius though. Is the Inside crown radius, from the head base to the top center inside? Edited by Castor63 - 19.Feb.2010 at 04:42

KobusErasmus Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 11.Sep.2009 Location: South Africa Status: Offline Points: 42	Posted: 20.Feb.2010 at 11:51
	Hi, Using Autocad 2010, I have done this attached file. Use the parametric commands. This profile can be expanded further and revolved to give you what you need. However if you do not have 2010, the profile can still be done using conventional draughting methods. Look at the drawing that I am attaching. 1. I first set up the centre line of the vessel. 2. Using offset - dia / 2 - place the one outside line of the outer dia. 3. Draw a circle with the centre point on the vessel centre line and the radius being the crown radius. Now from here there are 2 routes to take: First the long one: 4. Offset the outer dia line and the crown circle by the knuckle radius. 5. The intersection of these is now the centre point location for the knuckle arc - using that as reference draw a circle for the knuckle. 6. You now have the construction lines - using that draw the outline, offset to get the thickness, revolve, etc. and you have a 3d model. The quick and short way: 4. Using trim command, trim the crown circle so that only the bit remains between the vessel centre line and the outer dia line - see the drawing. 5. Using the fillet command with the radius set to the knuckle radius, fillet the crown arc and outer dia line. 6. From here if you have some 3d experience it should be easy to create a profile and revolve it into your vessel. Hope this helps, don't know if I understood your question correctly. Using ellipse and trimming it does not work, to create a 3d you need to join the lines into a polyline and ellipse does not join - even if you trim it. Its actually a pretty useless command and I very rarely use it. Ciao Kobus PS. I have tried to upload the file but for some reason I get an access denied message. Mail me if you need help.
	Kobus Erasmus Piping design draughting Contract draughting

KobusErasmus Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 11.Sep.2009 Location: South Africa Status: Offline Points: 42	Posted: 20.Feb.2010 at 11:53
	Ok here is the file. uploads/20100220_115309_Conical_shape.dwg
	Kobus Erasmus Piping design draughting Contract draughting

Castor63 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 23.Oct.2009 Status: Offline Points: 18	Posted: 20.Feb.2010 at 16:09
	That worked perfect thank you. I wirked at trying to use elipses and just couldnt figure out why I couldnt join the lines to create a solid after wards. None the less you way did the job

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Elliptical Heads For Pressure Vessels

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