centerlines for flange

[Reikaj]

Goodmorning everyone,

 

Is there a preferred method for showing centerlines?, see example. On the right side they are drawn complete and on the left just at the holes.

 

thanks again

[ReMark]

I usually use the one on the left. But it's not often that I have to detail a flange since everyone here (chemical company) knows what one looks like. It's not like we are fabricating them. Know what I mean?

[Reikaj]

yeah, this is being made here to work with some other parts they are making. I heard someone here call it a flange but maybe it is something else.

[ReMark]

Flange is the correct terminology.

[bonehead411]

We have to detail flanges regularly, and always as shown on the left of your example.

[Tankman]

We have to detail flanges regularly, and always as shown on the left of your example.

 

Like ReMark, I seldom detail a flange, all are ANSI dimensioned.

The installer just grabs one from stock, bolt kit, FF (full face) gaskets, and off he goes.

 

At times, I do rework flanges. Requires a drawing.

 

Here's a typical 8" PVC ANSI dimensioned flange.

If center lines were all over the place, drawing would be too busy and perhaps even confusing.

[Tankman]

Here's an example of my 10" PVC (or whatever) flange set.

 

End-user need a 10" PVC flange connection on a 64"Ø vertical storage tank.

 

Using a pair of 10" flanges, CNC milled the pair, one concave, one convex. Radius of 32".

A bolt kit, two FF flanges, 1-1/2"Ø gaskets for under the flat washers on the inside of the tank, don't want juice moving past the bolt threads. I TIG (or heliarc) the flat washers under the bolt heads to be sure juice doesn't follow the bolt threads. Drip, drip, drip.

 

Materials of construction need to be corrosion resistant; i.e.: HCl,

PVC, EPDM, hastelloy bolts. The bolts are frequently fab'd using all thread; nut and flat washer welded on one end. Bolt length as required.

 

*.jpg image shows a 6" flange set and an 8" flange set, both of which I machined to retrofit a customers existing storage tanks. Note the weld on the all thread/nuts. The second image, 6" flange set on a 48" Ø PE vertical tank, flange set machined to 24" radius.

[Tankman]

If flanges can't be machined, not enough meat. Machined spacers could be used along with the flanges however, bolts would be longer and a couple of additional FF (full face) gaskets required.

 

Flange, gasket, machined spacer, gasket, tank wall, gasket, machined spacer, gasket, flange, flat, lock, and nuts on the tank exterior. Gaskets under the bolt head flat washers on the tank interior.

 

Shown 6" PVC flange inside a 48"Ø PE storage tank.

 

I use a lot of flanges, pipe, fittings.

I purchased solid hastelloy flanges without bolt holes, tapped blind holes in the flanges which were used inside the tanks. Service was HCl, threaded hastelloy all thread into the flange. Exterior of the tank, clearance holes for the bolts.

Worked great.