Yarn dye tube having opposite end portions adapted for nested stacking

A stackable yarn dye tube comprising:

• a hollow, cylindrical, central body having opposite ends and a plurality of perforating openings for passage of a coloring dye therethrough;
• and
• first and second end portions respectively connected to the opposite ends of the central body, each of the first and second end portions including a substantially cylindrical ring connected to one of central body ends, the first and second end portions respectively including female and male elements at terminal ends thereof for nested engagement of adjacent tubes in a stack of aligned tubes,
• the first end portion ring having inner and outer surfaces defining a wall thickness therebetween, the first end portion ring further including a plurality of recesses extending inwardly from the outer surface thereof and arranged in multiple rows extending circumferentially about the ring, each of the recesses defining a reduced wall portion of the first end portion ring having a thickness that is at least one-half of the wall thickness of the first end portion ring,
• each of recesses of the first end portion ring being substantially oval in shape having arcuate ends for reducing stress concentrations in adjacent areas of the ring,
• the female element of the first end portion including a cylinder extending from a terminal end of the first end portion ring, the cylinder of the female element having opposite inner and outer surfaces, the inner surface of the female element cylinder having a diameter that is greater than a diameter of the inner surface of the first end portion ring such that an annular distance is defined therebetween,
• the terminal end of the first end portion ring defining a radially extending shoulder adapted for contact with the male element of an adjacent tube in a stack of aligned tubes,
• the first end portion further including a fillet at the terminal end of the first end portion ring between the shoulder and the inner surface of the female element cylinder, the fillet extending inwardly from the female element cylinder over a substantial portion of the annular distance for reducing stress concentrations in adjacent portions of the first portion end ring and the female element cylinder.