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US 5,052,476 AGranted
Heat transfer tubes and method for manufacturing
Assignee501 Mitsubishi Shindoh Co., Ltd.
InventorsShunroku Sukumoda, Seizo Masukawa, Haruo Kohno
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Abstract
A heat transfer tube having an inner surface in which are formed primary grooves and secondary grooves. The primary grooves parallel to one another, extending at an angle to the longitudinal direction of the heat transfer tube and secondary grooves parallel to one another, extending an angle to the primary grooves. At the intersections of the primary and secondary grooves is formed a series of pear-shaped grooves whose inner opening dimension is smaller than the dimension of the bottom of the pear-shaped groove.
Claims7
A heat transfer tube having an inner surface in which are formed:
- (a) primary grooves, having a U-shaped cross section and parallel to one another, extending at an angle to the longitudinal direction of the heat transfer tube,
- (b) secondary grooves, having a V-shaped cross section and parallel to one another, extending at an angle and intersecting with the primary grooves, and
- (c) pear-shaped grooves, having an opening width formed between the intersections of the primary and secondary grooves, having a trapezoidal cross sectional shape, said opening width being smaller than the dimension of their bottom portion, and are distributed regularly and uniformly along the primary grooves.
Dependencies are inferred from the claim text.