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A heat exchanger inner spiral-ribbed tube made of a hard metal such as stainless steel, titanium, or an iron-nickel alloy, and method of manufacture therefor for use in making a heat exchanger. The tube has an annular wall having an inner ribbed surface and an outer waved surface. The inner surface

A heat exchanger inner spiral-ribbed tube made of a hard metal such as stainless steel, titanium, or an iron-nickel alloy, and method of manufacture therefor for use in making a heat exchanger. The tube has an annular wall having an inner ribbed surface and an outer waved surface. The inner surface has a plurality of inner spiral ribs, each having a spiral angle. The spiral angle is about 18 degrees in the described embodiment. The tube-making method includes multiple steps in forming the outer waves and inner ribs simultaneously, progressively increasing the rib height while continuously pulling the tube in an axial direction.

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An inner spiral-ribbed tube for use in a heat exchanger or a refrigerator evaporator comprising: an annular wall tube having an elongate axis and an inner surface and an outer surface and consisting of a hard metal material selected from the group consisting of titanium, titanium alloy, stainless st

An inner spiral-ribbed tube for use in a heat exchanger or a refrigerator evaporator comprising: an annular wall tube having an elongate axis and an inner surface and an outer surface and consisting of a hard metal material selected from the group consisting of titanium, titanium alloy, stainless steel, and an iron-nickel alloy containing more than 10% by weight of nickel; said inner surface having a plurality of inner spiral ribs having a top and a bottom covering the entire inner surface of the tube and extending along the tube axis having a rib height of about 0.008 to about 0.016 inches, a width between the base of each rib of about 0.0125 to 0.040 inches, a width between the top of each rib of about 0.008 to 0.021 inches, and a pitch of about 0.027 to 0.070 inches, and said inner spiral ribs each having a spiral angle formed by a tangent to a point on the rib and a longitudinal line through the point and parallel to the elongate axis of the tube of between 8 to 45 degrees, and said outer surface having a plurality of outer spiral waves extending along the tube axis having a wave height of about 0.005 to 0.010 inches, a wave pitch of about 0.038 to 0.060 inches and a spiral angle of about 86 to 89 degrees.