Dear Sir,

can u explain that what is the distance between TL and weld seam

thanks
Ramin jafarvand

The "TL" refers to the tangent line between the cylindrical surface of the shell and the elliptical (etc) curvature of the formed head.

The "weld seam" would be the weld of the head to the cylindrical shell.

In most cases ellipsoidal and torispherical heads are provided with a short "straight flange" (or "head skirt" as referred to in ASME Code). This is necessary for manufacturing of the head; of course it could be trimmed off after manufacturing but this is typically not done. ASME UG-32(l) requires the straight flange if the head is thicker than the cylinder.

The distance between the TL and the weld seam is simply the length of the straight flange.

TL is imaginary line and WL is actual line
In drawing it is preferable to provide dimensions from TL
But Dist betn WL & TL can't have fixed value.

_________________
Niraj