US2331437A

US2331437A - Heat exchanging element

Info

Publication number: US2331437A
Application number: US403614A
Authority: US
Inventors: Harrison D Sterick
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-07-23
Filing date: 1941-07-23
Publication date: 1943-10-12
Anticipated expiration: 1960-10-12

Description

Oct. 12, 1943.

H. D. STEVRICK HEAT EXCHANGING ELEMENT Filed July 25, 1941 WITNESSE.

Mae/w. /LMM,

1.1 ATTORNEYS.

Patented Oct. 12, 1943 UNITED STATES PATENT GFFICE 2,331,437 HEAT EXCHANGING ELEMENT Harrison D. Sterick, Pittsburgh, Pa..v Application July 23, 1941 Serial No. 403,614

4 Claims;

I'his invention relates to heat exchanging elements, and more particularly to such elements of the n type.

It is among the objects of this invention to provide a iin type heat exchanging element which is easy and inexpensive to produce, simple in corrstruction, easy to mount in position, and highly eiilcient for conducting heat to or from an object the temperature of which it is desired to affect.

In accordance with this invention a strip of metal -is provided with a plurality of closely spaced transverse slits that form a row of very narrow ribbon-like ns. The slits extend only part way across this strip so vthat the uns are integrally connected to a body portion which extends lengthwise of thestrip. This body portion most suitably is spaced from both side edges of the strip to permit a row of ns to be formed on both sides of it. The strip'is bent or curved transversely to form a channel or tube-like mem-V ber with the body portion adapted to engage the object whose temperature is to be alected. The tins conduct heat either to or from the body portion depending upon whether the element is being used to cool or to heat the object to which it is attached. If the element is to be curved in the plane of the body portion the latter is provided with a series of holes to permit such curvature. These holes also make it easier to braze the body portion to the object it is attached to.

The invention is illustrated in the accompanying drawing in which Fig. 1 is a plan View of my heat exchanging element in its at condition before it has been bent transversely; Fig. 2 is an enlarged `transverse section through the nished element; Fig. 3 is a side view, partly broken away, showing the element mounted on a pipe coiled around a supporting member; Fig. 4 is a view similar .to Fig. 2 of a modication of the invention; Fig. 5 is a transverse section through a pair of concentric conduits showing the heat exchanging element of Fig. 2 inside the inner substantially parallel slits 2 that extend inwardly from the opposite side edges of the strip. The inner ends of the slits of the two rowsare spaced apart far enough to leave a solid body portion 3 extending lengthwise of lthe strip along its center. l The slits in the strip form a plurality 'ol' very narrow ribbon-like heat conducting ilns 4 integrally connected to the central bodyportion at their inner ends. If the strip is cut with shearsit will curve transversely of its own accord as it is cut. If cut in such a manner that it lies at, the strip may then by a. separate operation be curved transyersely so that the outer ends of the fins of the two rows tend to overlap, as shown in Fig. 2, to form a tube-like element. In /actual practice the curvature of the fins is not uniform and the overlapping is quite irregular, so that there are many projecting surfaces.

This heat exchanging element can be used in many places where it is desired to either heat or cool an object. For example,referring to Fig. 3 in either a hot water heater or a ref rgerating device the pipe 6 through which the hot water or refrigerating fluid iiows is threaded through the tube-like heat exchanging element and then may be wrapped helically around a supporting member 'l and secured in place. This clamps the body portion 3 of the heat exchanging element between the pipe and supporting member. In ease the supporting member is omitted Athe .body portion of the element is brazed or otherwise fastened to the pipe 6. If we assume that heatfrom a gas burner or the like rises around and .between the ns 4 of the heat exchanging element outside of supporting member 3, the ns will labsorb the heat and rapidly conduct it to the body .portion of the element from which it will be conducted `by pipe 6 to the water flowing through it. On the other hand, in v-a refrigerating device 4fins `l will take up the surrounding lwarm airand conduct .it to the refrigerant flowing through the coil, whereby the air around the \ns will be cooled. Or, if a hot uid is owing through pipe 6, the 'fins will radiate the heat to the;surround ing atmosphere and thereby cool the fluid.

In the modification .shown "in Fig. .4 the body portion 8 of the heat exchanging element is oii center-iso.thatonerowof fins 9 is narrower than the other row H1. Also, the element is bent transversely so jthat a channel-like element is formed in which :the ltwo :rows of ns are substantially parallel Vand `the wide row extends beyond the narrow row. yAirithat ows across the outer ends of the short 'ns will be intercepted by the projecting portions iof the long ns. This type of element :can y`besubstituted for the one shown inlFig. 3 if desired.

Fig. .5 'illustrates :a Away vin which two of my heat exchanging lelements can be used. The inner conduit l2 mayfibe the smoke stack of a furnace, while the outer conduit I3 may lead to a room that is to be heated. Extending helically around the inner surface of the inner conduit is one of my heat exchanging elements the body portion 3 of which is held tightly against the conduit by means of a spring wire coil I4 inserted in the element. Wrapped helically around the outside of the inner conduit is another of my heat exchanging elements which is held in position by a wire I5 engaging the inner surface ol its body portion 8. If desired, these heat exchanging elements may both be of the form shown in Fig. 2 or in Fig. 4. The hot waste gases flowing through inner conduit I2 are absorbed by the inner heat exchanging element and conducted through the inner conduit to theheat exchanging element that surrounds it. From this element the heat is radiated into the space between the two conduits and the air heated thereby is Conducted to a room for heating it. In this way the waste gases of al furnace are utilized for heating purposes. v

My heat exchanging element, by having very narrow fins on both sides of its central body portion, has substantially the maximum practicable surface area exposed to the atmosphere. This results in a very high degree of heat transfer. Due to the transverse curvature of the element it is readily mounted on a pipe or around a supporting object, because it can be telescoped o over a pipe or retaining wire. It is much quicker to slip the element over a pipe than to wrap it around the pipe as it has been necessary to do heretofore with similar types of heat exchangers.

In Fig. 6 a slightly modified heat exchanging element is shown mounted in a different way on a pipe.coil I6. The body portion I'I of the element engages the pipe between the convolutions rather than inside of the coil. To permit the body portion to be bent laterally so that it can follow the coil it is provided with a plurality of longitudinal openings I8 that allow the body portion to give laterally. These openings also make it easy to solder the body' portion to the pipe at spaced intervals, wherefore a separate supporting or attaching member is unnecessary. It will be observed that with this manner of mounting my heat exchanging element the ends of the ns I9 are disposed between the pipe convolutions instead of outside of the coil.

Many other uses for my heat exchanging elements will be apparent. One such use is the cooling ofair cooled airplane motors.

According to the provisions of the patent statutes, l'. have explained the principle and construction of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, Within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. The combination with a supporting member, of a heat exchanging element in the form of a metal strip having a body portion extending lengthwise thereof and spaced inwardly from the side edges of the strip, said strip being provided with a plurality of closely spaced slits extending outwardly from both sides of said body portion to said edges of the strip and forming two rows of narrow fins, said strip being curved transversely and coiled around said supporting member, and a coiled pipe engaging the inner surface of said body portion and holding it against the supporting member.

2. In combination, a metal strip having a central body portion extending lengthwise thereof and having a plurality of closely spaced slits extending outwardly from both sides of said body portion to the side edges of the strip whereby to form two rows of ribbon-like fins, said strip being curved transversely to form a tube-like element with said two rows of fins partially overlapping, and a pipe extending through said tube-like element in engagement therewith.

3. In a heat exchanging device, a coiled member, and a metal strip having a central body portion extending lengthwise of itself and having a plurality of closely spaced slits extending outwardly from both sides of said body portion to the side edges of the strip whereby to form two rows of ribbon-like fins, said body portion extending lengthwise along said coiled member in engagement therewith and with its surface substantially parallel to the axis of the coil, and said fins extending at least part way around said member.

4. In a heat exchanging device, a coiled pipe, and a metal strip having a central body portion extending lengthwise of itself and having a plurality of closely spaced slits extending outwardly from both sides of said body portion to the side edges of the strip whereby t0 form two rows of ribbon-like fins, said body portion extending lengthwise alon'g said coiled pipe in engagement therewith and with its surface substantially parallel to the axis of the coil, and said ns extending at least part way around said pipe.

HARRISON D. STERICK