Re: DIN Flange Detail Drawings

From: <Christopher>
Date: Sat Nov 23 2002 - 13:48:00 EST

>A piece of equipment with 12" DIN-spec connection needs a mating flange,
I've got a couple of 40 year old DIN specification sheets translated in to English. My guess is that the basic geometry hasn't changed, but you never know. You really ought to go to Global Engineering or some fairly fancy technical or reference library (Montreal must have dozens) to get copies of the specs and determine exactly what you're trying to match.

First, there isn't any such thing as a 12 inch DIN flange. The specs I have refer to 'nominal widths' and the closest is 300NW apparently intended for 300NW pipe. The geometry and bolting depend on the pressure, just like US flanges, and of course they're specified for DIN standard piping and for DIN material specifications for forging--not plate.

The whole material spec/flange geometry/attached piping/gasket/bolting/flange design methodology gets real complicated real quick. If you're doing a replacement part for a German-built system made long ago, you can probably just drop in a replacement flange _provided_ it meets the DIN spec in its entirety. If you're trying to mate US standard and DIN standard components, you'll need to meet two different specification systems and envelope two different design criteria: DIN to make sure the German system works properly and ASME Code to make sure the system can operate legally. I've done this a couple of times, and it's pretty nasty business--not something you look up in a catalog.

The specs I have are for weld neck flanges for 'nominal pressures' of 25 bar and 40 bar. At least I think the pressures are in bar if 1 bar = 40kp/cm^2 (Really--that's what it says...). Just in case you're thinking about it, I don't have a scanner, getting all the relevant specs to you is more work than I'd consider for free, and it's a long shot that a pair of 40 year old specs cover the flange configuration and pressures you're matching. Cheaper to go to the Global Engineering web site and bite the bullet. The DIN specs may also have been superseded so long ago that you might not even want to bother with them--just do a custom flange using ASME Code design methodology and your client's bolt and raised face pattern. Or maybe current ISO flanges will mate with DIN flanges, and you can order one from Texas Flange. You might want to check bolt patterns against ISO standards:

25bar 300NW weld neck 16 M27 bolts on a 430 mm BC 395mm RF OD 40bar 300NW weld neck 16 M30 bolts on a 450 mm BC 410mm RF OD

Material spec for both is St-37 forgings. Again--both specs are for weld neck flanges according to DIN 2634 and DIN 2635 translated in 1966.

Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=5OaYrt9mHxgpGQIP8O1CvLLmOoMP9iogvLwwSGSSuRo8cNBfexQwbHxj1TmqqhwwrilHgF-epRev">chrisw@skypoint.com</a> | this distance" (last words of Gen.

___________________________| John Sedgwick, Spotsylvania 1864)

<a href="http://www.skypoint.com/~chrisw">http://www.skypoint.com/~chrisw</a> Received on Sat Nov 23 13:48:00 2002