Cone with Branch Hole flat pattern

What it is

The cone with the nozzle hole already marked — the mate of the cone branch, as the holed shell is the mate of the pipe branch. And here it matters more than on a pipe: marking a hole on a cone by hand is far worse than on a cylinder, because the surface does not open into a rectangle. It opens into a sector, and the hole's curve has to be carried into it.

Where it is used

Conical hoppers and silos with a nozzle, conical vessel bottoms with a take-off, cyclone inlets, bins with a side discharge.

Measurements the calculation needs

• D1 Diameter 1
• D2 Diameter 2
• H Height
• D Diameter
• Y Measurement Y
• DV Divisions
• THK Thickness

Worked example

The values the form comes pre-filled with, run through the tool itself:

Diameter 1	300 mm
Diameter 2	900 mm
Height	800 mm
Diameter	200 mm
Measurement Y	500 mm
Divisions	32
Thickness	6 mm
The flat pattern fits a plate of	2273 × 1084 mm

Frequently asked questions

Why isn't the hole symmetric in the sector?

Because the cone flares. At the top the nozzle meets the wall where it is wider and further from the apex; at the bottom, narrower and nearer. In the sector that becomes a curve pulled outward on one side — nothing like the nearly symmetric hole on a shell.

Which diameter do I enter?

The HOLE, as on the holed shell — for a nozzle set on top of the cone it goes at the nozzle's bore, for one set in, at its outside diameter. The welder decides.

Where does the cone's seam go?

Diametrically opposite the hole. A longitudinal weld does not run through a cut-out, and on a cone it is already the most critical joint in the part.

Does this hole match the cone branch in this catalogue?

It does, and it is its mate. Enter the same cone, the same height and the same diameter in both parts and you have both patterns for the job — the branch and the cone.