US 5,311,661 AGranted

Method of pointing and corrugating heat exchange tubing

AssigneePackless Metal Hose, Inc.

InventorLothar R. Zifferer

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Abstract

A method for producing corrugated tubes of substantially high surface area for use in tube-in-shell heat exchangers which are particularly efficient for cooling water involves pointing a heat exchange tube at both ends to reduce the diameter substantially and increase the wall thickness of the pointed ends and then corrugating the tubes linearly. The tubes each having intermediate portions linearly corrugated to provide equally spaced deep corrugations extending in a straight line parallel to the axis of the tubes. The corrugations, which are equivalent to tubes, multiply the amount of heat transfer attainable from the point diameter selected for attachment to the tube sheets. The ratio of the surface area of the corrugated body portion to the surface areas of said reduced ends, per unit length, is in the range from about 1.5:1 to about 4:1. It also makes possible the contiguous relation of each tube to the surrounding tubes. The nesting of the tubes in a heat exchanger minimizes by-pass of the fluid and controls the velocity essential to achieving turbulent flow and attendant high rates of heat transfer.

Claims10

Dependent claims

A method of producing a high surface area tube for use in tube-in-shell heat exchange apparatus comprising

providing a thin wall heat exchange tube of selected length and wall thickness facilitating a high heat transfer rate,
providing at least one tapered tube pointing die of selected size and smooth conical taper having a large entrance end and a small cylindrical exit opening,
pointing said tube by the steps of
first forcing the ends of said tube into said tube pointing die to substantially reduce the diameter uniformly to enter said exit opening and correspondingly increase the wall thickness of a selected length of said ends, and
said tube pointing thus producing a tube having uncorrugated smooth cylindrical ends of substantially reduced diameter and increased wall thickness suitable for securing in the tube sheet of a tube-in-shell heat exchanger and a main unreduced cylindrical body portion which is of the initial wall thickness and tapering at each end in a smooth conical taper to the increased thickness of said end, and then
linearly corrugating said main body portion along substantially its entire length to produce a smaller diameter portion with linear corrugations extending along substantially the entire length of said main body portion and terminating at said tapered end portions adjacent to said reduced diameter smooth cylindrical end portions and thus providing a surface area for heat transfer which is substantially greater than the surface area said ends.

3 more elements

Dependencies are inferred from the claim text.