Not applicable.
(1) Field of the Invention
The invention relates to heat exchangers and is directed more particularly to an improvement which renders current heat exchangers more efficient.
(2) Description of the Prior Art
Conventional heat exchangers typically include a tube for flowing a working fluid therethrough, the tube passing through or proximate a thermal medium, hot or cold, to heat or cool the working fluid. The thermal medium may itself be a flowing fluid.
In an effort to improve heat transfer from the thermal medium to the working fluid, in some instances, the outer surface of the tube is increased by the use of external fins or the like. In other instances, a structure is placed in the tube to generate vorticity or turbulence within the tube to increase heat exchange.
For example, in U.S. Pat. No. 4,062,524, issued Dec. 13, 1999 to Dieter Brauner et al, there is disclosed an arrangement of comb-like plates for static mixing of fluids. In U.S. Pat. No. 4,208,136, issued Jun. 17, 1980 to Leonard T. King, there is shown a tube with mixing elements therein, the elements being shaped to impart a rotational vector to portions of the flow stream. In U.S. Pat. Nos. 4,466,741 and 5,312,185, issued Aug. 21, 1984 and May 17, 1994, respectively, to Hisao Kojima, there are shown arrangements of helical blades mounted in tubes. In U.S. Pat. No. 5,518,311, issued May 21, 1996, to Rolf Althaus et al, and in U.S. Pat. No. 5,803,602, issued Sep. 8, 1998, to Adnan Eroglu et al, there are shown triangularly-shaped vortex generators mounted in flow ducts.
The above-noted prior art devices have inherent disadvantages, including pressure drop through the heat exchanger. Helical designs and structures extending width-wise of the tube require increased power input to compensate for friction losses. Further, the relatively large volume of some of the above-noted mixing elements consume much of the cross-section of the tube, reducing the volume available for fluid flow. Still further, the relatively large volume devices result in much heavier tubes.
Accordingly, there is a need for an improved heat exchange tube and system in which heat transfer within a tube conveying a working fluid is substantially enhanced, without adding a substantial volume of blocking structure in the tube or significant weight to the tube, and which does not cause a meaningful pressure drop in the tube, or require further power input to force the fluid therethrough.
An object of the invention is, therefore, to provide a heat exchange tube featuring structure therein which improves heat transfer, but does not occupy a substantial volume of the tube nor add substantial weight to the tube.
A further object of the invention is to provide such a heat exchange tube in which the internally-mounted structure does not precipitate a meaningful pressure drop in the tube and does not increase resistance to flow such as to require added power to flow the working fluid therethrough.
A further object of the invention is to provide a heat exchange system featuring a tube as described immediately above.
A still further object of the invention is to provide a method for improving heat exchangers, including conventional heat exchangers.
With the above and other objects in view, a feature of the present invention is the provision of a heat exchange tube comprising a tubular conduit for flowing a working fluid therethrough and for conducting heat between the working fluid and a thermal field proximate to the tube, and a wire extending axially through the tube and spaced from an inside surface of the tube.
In accordance with a further feature of the invention, there is provided a heat exchange system including a thermal source providing a fluid heat exchange medium, a heat exchanger for receiving the heat exchange medium, a heat exchange tube extending through the heat exchanger and adapted to flow working fluid therethrough, and a wire extending axially through the tube and spaced from an inside surface of the tube.
In accordance with a still further feature of the invention, there is provided a method for improving heat exchange capacity in a heat exchange tube including a tubular conduit for flowing a working fluid therethrough and for conducting heat between the working fluid and a thermal field proximate the tube, the method comprising providing a wire in the tube extending axially of the tube and spaced from an inside surface of the tube.
The above and other features of the invention, including various novel details of construction and combinations of parts and method steps, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular devices and method embodying the invention are shown by way of illustration only and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.