The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 23, 2001
Filed:
Feb. 22, 1999
Hiroyuki Takahashi, Hatano, JP;
Chikara Saeki, Hatano, JP;
Kabushiki Kaisha Kobe Seiko Sho, Kobe, JP;
Abstract
In boiling heat transfer tube, fins,are provided on an outer surface of the tube body,in a manner such that the fins,each extend in a peripheral direction of the tube and a direction inclined to the tube axis at a pitch P,in the tube axial direction. Protrusions,and recesses,are alternately formed in a length direction of a fin, a protrusion coming after a recess or vice versa, by being pressed. Opening,widths at the top ends of the cavity,between an adjacent pair of fins,are narrowed by inward jutting-out of the fins at both recesses,and protrusions,A profile of each of the protrusions in section perpendicular to the tube axis assumes a trapezoid. An opening width (W) between protrusions in section including the tube axis is 0.13 mm<W ≦0.40 mm, an angle (&thgr;) formed between opposed side surfaces of each recess in section perpendicular to the tube axis is 55 degrees or less. A pitch (P,) of the recesses or the protrusions in section perpendicular to the tube axis is 0.28 mm≦P,≦0.55 mm. A pitch (P,) of the cavities in section including the tube axis is 0.50 mm≦P,≦0.90 mm. Ribs are provided on an inner surface of the tube body in a spiral fashion, wherein a rib lead angle (&agr;) to the tube axis is 41 degrees≦&agr;≦50 degrees, a rib height (h) is 0.22 mm≦h≦0.45 mm and a rib pitch (P,) in a tube axial direction is 2.6 mm≦P,≦6.5 mm.