Offset Pipe Branch (Tangential Inlet) flat pattern

What it is

The branch whose axis does NOT cross the main pipe's — the tangential inlet. The ordinary branch requires the two axes to intersect, and so cannot do this one: cyclone inlets, tank feeds, any branch set to one side so the flow enters spinning instead of head-on.

Where it is used

Tangential cyclone and hydrocyclone inlets, swirl tank feeds, side take-offs on headers, runouts offset for want of room.

Measurements the calculation needs

• D Diameter
• D2 Diameter 2
• C Branch length
• V Outlet offset
• DV Divisions
• THK Thickness

Worked example

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

Diameter	150 mm
Diameter 2	500 mm
Branch length	500 mm
Outlet offset	160 mm
Divisions	32
Thickness	5 mm
The flat pattern fits a plate of	456 × 408 mm

Frequently asked questions

What changes in the pattern compared with the ordinary branch?

The symmetry. On a centred branch the mouth has two equal troughs; here it has one deep and one shallow. At the tangential limit the shallow one disappears altogether and the mouth touches the pipe's side line.

Can the offset reach the side of the pipe?

It can, and that is exactly the case the part is named for: with the offset plus the branch's radius equal to the pipe's radius, the branch is tangent. The calculation accepts equality. Past it the branch would run off the side and there would be no closed mouth to cut.

Where do I measure the length from?

From the AXIS of the main pipe to the end of the branch, as on the ordinary branch — the centre-to-face dimension.

And at zero offset?

The part is exactly the ordinary branch at 90 degrees, and both are in this catalogue. I checked station by station: they give the same heights, with no difference at all.