Petticoat pipe

from The Collaborative International Dictionary of English v.0.48

Petticoat \Pet"ti*coat\, n. (Zool.) [Petty + coat.]
   A loose under-garment worn by women, and covering the body
   below the waist.
   [1913 Webster]

   {Petticoat government}, government by women, whether in
      politics or domestic affairs. [Colloq.]

   {Petticoat pipe} (Locomotives), a short, flaring pipe
      surrounding the blast nozzle in the smoke box, to equalize
      the draft.
      [1913 Webster]