7 inch 90 degree elbow
7 inch 90 degree elbow
(OP)
I have problem with finding the 7 inch elbow, it must be seamless. could you please name a local vendor in your country or could you please give me some advice for manufacturing it properly.
Thanks
Thanks





RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
you must get smarter than the software you're using.
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
I want to ask you, my colleagues, this, it is possible to make a 7'' pipe from plate then fully RT it then bend it. in this situation maybe this type of welding and cold work would cause a lot of residual stress then we need to normalize it ( i am a freshmen mechanical engineer just got out of school and started working, if i sound ridiculous, forgive me :) )
RE: 7 inch 90 degree elbow
Seven inch does not appear in any of the current ASME codes 36.10, 16.9 or API 5L as a standard size and I've never heard of it.
Perhaps just ask nicely for any suppliers your client has used in the past.
It is possible to make anything, but a one off cost will be huge as it either has to be machined from a solid block or made specially unless you happen on someone who makes this very odd size regularly.
Is this an existing plant / pipe or new design or what? what code does the pipe specification call up? what material is it made from? what wall thickness are you looking for? Is this a long radius elbow or a bend?
Perhaps you could get an 8" elbow with very high wall thickness to get your nominal ID of 7"
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: 7 inch 90 degree elbow
But the point I want to raise is in regard to the requirement for "smoothness". The only advantage of seamless vs welded in terms of smoothness would be the weld seam on the inside. The cost of grinding and polishing that seam would be small compared with having custom units fabricated, and 7" is large enough to be able to polish inside easily. Do you have a requirement for very high hygiene standards? This is unusual in a relatively large pipe - it doesn't sound like a pharmaceutical plant.
If the requirement for smoothness is because of friction then you need to point out to them that the pressure drop caused by the change in direction through an elbow far outweighs the friction against the surface - and in any case the difference between welded and seamless pipe would be unmeasurably small.
Katmar Software - AioFlo Pipe Hydraulics
http://katmarsoftware.com
"An undefined problem has an infinite number of solutions"
RE: 7 inch 90 degree elbow
- ERW is less expensive
- ERW has much less ovality
- ERW has much more consistent wall thickness
- ERW gives me fewer welds that fail inspection
The only people I run into that insist on seamless are people who were burned badly by the crap pipe that came out of U.S. mills in the 1970s and early 1980's. That stuff was horrible and drove everyone to Japanese and European mills. When USX built the Fairfield plant in Virgina and Lone Star revamped their Texas plant that all changed and US pipe set a new standard that the rest of the world took 5 years to catch up to. Since early 1990's ERW has been a far superior product to seamless in every size where it is available.David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
This is 7" NB pipe alright (7.625" OD). I have found the odd reference to 7" pipe in some catalogues, but when you click on further links it then disappears. I've never seen or heard of 7" pipe before so I'm all out of ideas.
I can only suggest you keep on searching and if possible see if you can talk to the operators, find an old design and talk to the designers or even a material certificate for the existing pipe buried in the plant archives. Try a few pipe stockists - even if they don't stock it they migth know of a vendor who would do "specials", but brace yourself for the price....
It shouldn't be up to you to find this on your own - you've looked hard (I hope), asked a few people and now you need to go to your supervisor, not the client as he doesn't sound very helpful, and tell him your story.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
What is this elbow connected to?
Piping Design Central
RE: 7 inch 90 degree elbow
I did find one table with 7-inch, but it only had wall thickness for Sched 40 which is 0.301 in [7.6 mm], Sched 80 which is 0.5 in [12.7mm] or XXH which is 0.875 inch [22.2 mm].
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist
RE: 7 inch 90 degree elbow
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
RE: 7 inch 90 degree elbow
Piping Design Central
RE: 7 inch 90 degree elbow
Go on google and try "193.7 mm outside diameter pipe"
I found quite a few examples of 193.7 mm OD x 5.6 mm WT pipe (IS 3589-1991 & EN 10297-1)
Didn't bother looking for elbows as I thought you could follow that up,
Cheers,
DD
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
This is an example of what you get after typing "193.7 mm elbow" . http://www.gvzglasshouses.co.uk/products-a-parts-l...
Remember if you buy a 90 or 45, you should be able to cut it back to a 30 degree without a big problem with a grinder.
Still never seen one in petro chem plants, but maybe in other industries it is a bit more common.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: 7 inch 90 degree elbow
There's no material specified for that elbow (other than "steel") and I'm wondering why such an odd-size fitting was created when standard sizes exist.
I seem to recall seeing a 5" connection once on a European-sourced compressor and of course metric DIN and JIS sizes, but like LittleInch, never 7" in petrochem, cryo, pulp and paper or chem.
Maybe the greenhouse industry is somehow special and they need oddball pipe sizes...
Piping Design Central
RE: 7 inch 90 degree elbow
RE: 7 inch 90 degree elbow
Thanks europipe, not enough eurexperience I guess.
Piping Design Central
RE: 7 inch 90 degree elbow
So, it is a single 30 degree bend. That's easy.
Machine from round stock the "193.7 mm elbow" by machining the OD to 193.7 mm at least 1.2 meter long, then machine the ID as required for the wall thickness actually needed using the OD to maintain alignment in the lathe.
Put in a simple pipe roll bender (3-roller type) and roll the center of the 1.2 meter long "pipe" to 30 degrees bend.
Cut off excess straight stock on both ends. Weld prep the ends by hand.
RE: 7 inch 90 degree elbow
http://www.tenaris.com/shared/documents/files/CB43...
Cheers,
DD