I’ve been describing tank ends, and what all flanging operators do to them. Better to show than tell. I’ll start with an ASME flanged & dished head.
By being ASME code, certain requirements must be met. The degree of the drop radius (dr) must be equal to the diameter (od, or outside diameter, in this case, although if the customer requires the diameter can be measured from the inside, which would make it id). The inside corner radius (icr) must be six percent of the diameter. The straight flange (sf) and overall height (oah) can be whatever the customer wants. I don’t even know what idd stands for, we don’t measure it. And thk, of course, is the thickness of the metal.
This is a standard head. Same as an ASME, but the requirements aren’t as strict. TL stands for tangent line, the point where the bottom of the straight flange meets the top of the icr, which is kind of fuzzy.
This is an elliptical. It is much deeper and rounder than an ASME or standard. The diameter is twice the drop radius (hence the ‘2:1 ratio’). Another way of saying this is the drop radius is 50 % of the diameter.
This is an 80-10. The drop radius is 80 % of the diameter. This head has a measurable icr, whereas a 2:1 elliptical doesn’t. The icr is 10% of the diameter, hence the name 80-10.
This is a dished only. It doesn’t get flanged, only pressed. Although we do trim the edge to a required diameter, with either a radial trim or a vertical trim. A radial trim is one which maintains the angle the edge of the head was pressed to. A vertical trim is self-explanatory.
This is a flanged only. It doesn’t get pressed. We turn up the edge of a flat metal circle.
This is a flared and dished. Instead of turning up the edge of a dished head to 90 degrees, we flare it out to 45 degrees.
This is a shallow head. The drop radius is much less than that of an ASME. Which makes the overall height shallower.
This is a cone. Pressed, or bent, segments are welded together into the cone shape, then we turn up the edge to give it an icr and a straight flange.
I couldn’t find a drawing of a reverse head. Instead of turning up the edge in the direction of the radius, to make a bowl shape, the head is flanged upside-down and the edge is wrapped completely around the icr roll to give it this weird shape.
Also couldn’t find a drawing of a hemisphere. These are pressed segments welded together to a dish only head. Sometimes we put these in a flanging machine to spin it to a certain circumference (they are pretty close to start with) and to machine the edge.
These are the different kinds of tank ends I’ve worked on at Brighton.