Heat transfer unit

Oct. 8, 1940.

2,217,469

W. R. CLARKE

HEAT TRANSFER UNIT

Filed March 9, 1940

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Patented Oct. 8, 1940

2,217,469

UNITED STATES PATENT OFFICE

2,217,469 HEAT TRANSFER UNIT

Walter R. Clarke, Hartford, Conn., assignor to The Vulcan Radiator Company, Hartford, Conn., a corporation of Connecticut

Application March 9,1940, Serial No. 323,168

Claim. (Cl. 257—262)

This invention relates to heat transfer units and more particularly to those heating radiators of the type which comprises a central tubular metallic core with a plurality of spaced sheet 5 metal fins secured thereon to provide extended radiating surfaces. The object of this invention is to so form fins for such radiators that not only will their radiating surfaces be more extended but the flow of air over their surfaces will be 10 more effective than Is the case with the fins in common use of the same exterior contour and size.

In attaining the object of this invention each fin is stamped from thin sheet metal, preferably 15 copper, alternately from opposite sides to form dome-shaped protuberances on one face and conforming cavities on the opposite face, and these fins are secured side by side, with small spaces between, on to a tubular core so that the pro20 tuberances on one fin are opposite the cavities on the adjacent fins. Fins so formed are stiffer and more rigid therefore can be made of thinner stock, and they provide greater radiating surfaces, as well as present a more ornamental effect 25 when assembled, than smooth fins, such'as are shown in Patent No. 1,916,656, July 4, 1933, and what is of more particular value the alternating protuberances and cavities so effect and change the direction of and cause such circulation of the 30 air currents as they pass over the surfaces between the fins that a maximum of radiation pfflciency is attained with a minimum amount of metal.

In the accompanying drawing

Fig. 1 shows a side view of a portion of one section of a radiator with a few fins formed in accordance with this improvement.

Fig. 2 shows on larger scale a face view of the fin and section of the core.

Fig. 3 is a view looking at the left hand edge of Fig. 2.

Fig. 4 is a view looking at the right hand edge of Fig. 2.

Fig. 5 is a section on line 5—5 on Fig. 2.

The unit shown has a central tubular core ( which is commonly made of copper or similar good heat conducting metal of the required thickness, diameter and length. The fins 2 are stamped to shape from thin sheet metal, prefer50 ably copper, to any approved size and outline either rectangular or circular. The fins have a central perforation 3 and they are slipped upon and tightly secured to the core in a manner similar to that illustrated in Patent No. 1,646,384, 55 Oct. 25, 1927.

The fins which form the subject of this invention are, in the areas beyond the central perforations. stamped from opposite sides to pro duce on each side protuberances 4 and cavities 5, the design being such that on one face of the fins the protuberances alternate with the cavities and on the opposite face the cavities alternate with the protuberances. The protuberances may 5 be dome-shaped or cone-shaped, preferably the former, and the cavities substantially conform thereto. The protuberances may vary in size, and preferably they are located in close proximity on both sides, but if desired they could be on one 10 side only.

Air flowing through a radiator provided with sections having such fins as herein described has no straight paths, it passes easily but alternately over and around the protuberances and into and 15 out of the cavities in very circuitous and agitated streams and takes off a maximum amount of heat from the thus extended areas of the fins. In fact it has been found that owing to the passages taken by the air streams the radiation effect is 20 increased to a greater degree than is the increase in surface area produced by the protuberances.

It has been demonstrated in actual use that the efficiency of radiators provided with sections having fins of the form described is greatly increased 25 over the efficiency of prior radiators of this type provided with the commonly used fins, and thus a smaller fin resulting in a smaller radiator may be used to produce the same radiation effect as the prior radiators. 80