US2453448A - Heat exchanger - Google Patents

Description

'Nov; 9, 1948. M. H. MpTURK j 2,453,448

I HEAT EXCHANGER Filed Nov. 15, 1945 A INVENTOR jections from the material of the tube.

Patented No 48 Morton n. Mc'l'urk, Philadelphia, Pa. Application November 15, isia'senai No. 628,763

This invention relates to heat exchanging apparatus in general and in particular to apparatus for effecting temperature exchange between the fluid contents of a tube and conditions exteriorly of the tube. The contents of the tube may be fluid for a liquid refrigerant; or hot or cold water; or brine. The invention is peculiarly adapted for use as a condenser for condensing hot gases to liquids. It may also be used in installations in which steam is used within the tube for 7 Claims. (Cl- 257-26230) heating, or for a process involving the cooling of ahot gas.

It is the general objective of all heat transfer equipment to obtain the greatest possible heat transfer within a given space, as for example from or to a pipe, assembly of pipes or tubes or plates. The present invention is based on the discovery that a highly emcient heat exchanger constructionis one in which the exterior of a tube is provided with a multiplicity of wires, minute metal projections substantially comparable to metal hairs, which are connected to the exterior of the tube and project outwardly therefrom.

An important factor in connection with any such heat transfer apparatus is that the vanes, baiiles, wires or the like must be firmly secured to the tube or other element containing material to be treated. In some installations it has been proposed to cut grooves in the surface of tubing and also to gouge out shavings or wire likepro- According to the present invention, however, it is possible to use a thin tubing, too thin, to permit any shaving or cutting of the surface, and to provide for positive heat transference by a special type of mounting of heat conducting wires on the tube on which they are used.

Accordingly, it is one of the objects of this invention to provide a simple, yet highly eflicient,

arrangement for mounting hair-like wires or minute rods on the exterior of tubes, such as copper tubes. This is accomplished without cutting, damaging, or thinning the wall'of the tubing, an important consideration when operating with thin wall copper tubing.

The foregoing and additional details of the in- Fig. 2 is a view of one form of mounting in which the center one of three securing wires is larger than the wires at either side thereof;

Fig. 3 is a view of a modification in which the center one of the three securing wires is smaller than either one of the securing wires at opposite sides thereof;

Fig. 4 is a view of a modification of the securing wires in which the center Wire is round in crosssection and the lateral wires are rectangular; and

Fig. 5 is a view of one form of the mounting in which the three securing wires are of substan tially the same size.

Referring in detail to the drawings, I represents the wall of a section of metal tubing, such as thin copper tubing. The problem may be one relating to the best method and apparatus for throwing off heat from the contents of the tube, or conversely, this apparatus is adapted for use for absorbing heat and transferring it from the exterior to the contents of the tube, as, for' example, in air conditioning or refrigeration. The direction of heat transference is not the important factor; rather, this invention is directed to the particular mounting of a multiplicity of fine wires on the exterior of the tube. It is necessary that the wires be held closely to the tube and that the heat transfer relation between the wire and the tube must be as positive as possible. It is believed that the use of line wires is more efficient than the use extending outwardly and unsecured. These wires are looped around or folded over to partially encircle the intermediate one of three securing wires, as will be explained. In the several figures, 2 indicates the individual heat conducting wires. The securing means for each of the heat conducting .wires includes three wires 3, 4 and 5 positioned closely together and which, as indicated in Fig.

vention are set forth in the following specification and claims and illustrated in the accompanying drawing and in which:

Fig. 1 represents a sectional view through a length of tubing and on the surface of which are .with the details of this invention;

1, are wound spirally around the tube i. The two exterior securing wires are respectively 3 and 4 and are directly against the surface of the tube l. 5 identifies the intermediate wire, and the individual heat conducting wires are looped about and'passed between the wire 5 and the tube 1. The opposite end portions of the individual heat conducting wires 2 extend upwardly and outward- 1y from beneath the wire 5, one end extending between the securing wire 3 and the wire 5 and the opposite end portion of the heat conducting wire 2 extending between the center wire b and the outside securing wire 4.

- The relative size and shape ofthe securing wires is important in the ultimate position of the opposite endportions of the heat conducting wires ,2. As shown in Fig. 2, the intermediate or ceneral wires 3 and 4 with-the result that the lat-- eral wires tend to push the respective sides of thewire 2 across the top of the wire I. Thus,

the position of the wire 2 is such that the two projecting arms thereof above the securing wires are crosse In Fig. 4 the securing wires include rectangularly shaped, lateral wires 3 and 4 and a central between adjacent tubes so as to lightly tap the wires to dislodge dust. Preferably such cleaning operations are. performed while an air blast or an air fan is functioning so that the dislodged dust can be readily blown away.

From the foregoing, it will be clear that this construction provides for a high degree of'heat transference and without alteration or weakenwire which is shown as round in cross-section.

By using rectangular wires 3 and 4, substantially parallel adjacent faces engage the heat conducting wire 2. The opposite arms of the wire 2 are held against outward movement and the twoportions of the wire 2 can "be substantially parallel,

as shown in Fig. 4.

In the arrangement shown in Fig. 5, in which the three securing wires are substantially the same size, the extending portions of the heat conducting wires 2 are permitted to spread slightly although not so wide apart as shown in Fig. 2 in-,

which the lateral wires are smaller than the central wires.

To perfect the heat conducting relation, it is desirable that the securing wires 3, 4 and 5, and

the heat conducting wires 2, be as close together.

as possible and closely applied to the tube as is practically possible. In accomplishing this resuit, the three wires 3, 4 and 5 should be applied to the tube under considerable tension. Also, the contact should have a bonding material, such as solder, to insure a positive bond and contact between the tube and the wires. It is desirable that the solder extend from the tube to the heat conducting wires 2 as well as between the tube and the securing wires 3, 4 and 5. It has beenfound that one satisfactory method of applying this solder is as a paste applied with, or under or over the securing wires. It is expedient to use a solder coated wire. and the bond between the wire and the tube surfaces may be made by tin plating after the parts have been. assembled.

One of the advantages inherent to the construction of this invention is that the open wires do not retain dust and dirt to the extent characteristic of broad surfaces. Also, whereas quite a problem is involved in cleaning. condensers and condenser surfaces, the wires of the present improvement can be cleaned by the use of a blast of air or light strokes of a slender tool thrust ing'of the tube-on which the heat exchanger wires are mounted. I

I claim:

1. In a heat exchanger, a tube having a wall of substantially even thickness throughout and adapted to contain fluid the temperature of which is to be influenced, wire conductors on the exterior of said tube, and securing means for holding said wire conductors-on said tube, said securing means comprising three wires encirclingsaid tube and arranged side by side, and said wire conductors being in heat exchanging position on the exterior of said tube and extending between the center one of said three wires and said tube and thence between said. center wire and'thesecuring wires at the opposite si des thereof, said wire conductors extending outwardlyfrom said tube and from position between said securing wires, the outer two wires of said three wires of said securing means being directly against-the surface of said tube.

2. In a heat exchanger, a tube adapted to contain fluid the temperature of whichis to be influenced, wire conductors on the exterior of said tube, and securing means for holding said wire conductors on said tube, said securing means comprising three wires encirclingsaid tube and arranged side by side, and said wire conductors being in heat exchanging position on the exterior of said'tube and extending between the center one of said three wires and said tube and thence between said center wire and the securing wires at the opposite sides thereof, said wire conductors extending outwardly from said tube and from position between said securing wires, the outer two wires of said three wires of said securing means being directly against the surface of said tube.

3. In a heat exchanger, a tube adapted to contain fluid the temperature of which is to be influenced, wire conductors on the exterior of said tube, and securing means for holding said wire conductors on said tube, ,said securing means comprising three wires encircling said tube and arranged side by side, and said wire conductors .the opposite sides thereof, said wire conductors extending outwardly from said tube and from position between said securing wires, and. having the outermost portions terminating as unattached ends, the outer two wires of said three wires of said securing means being directly against the surface of said tube.

4. In a heat exchanger, a tube adapted to contain fluid the temperature of which is to be infiuenced, wire conductors on the exterior of said tube, and securing means for holdin said wire conductors on said tube, said securing means com: prising three wires encircling said tube and arranged side by side, and said wire conductors being in heat exchanging position on the'exterior of said tube and extending between the center one of said three wires and said tube and thence between said center wire and the securing wires at opposite sides thereof, said wire conductors extending outwardly from said tube and from position between said securing wires, and having the outermost portions terminating as 1111- attached ends, the outermost of said three securing wires being larger in diameter than the diameter of the center wire of said three wires, the

outer two wires of said three wires of said securing means being directly against the surface of said tube. 5. In a heat exchanger, a tube adapted to contain fluid the temperature of which is to be in fluenced, wire conductors on the exterior of said tube. and securing means for holding said wire conductors on said tube, said securing means comprising three wires encircling said tube and arranged-side by side, and said wire conductors being in heat exchanging position on the exterior of said tube and extending between the center one-of said three wires and said tube and thence between said center wire and the securing wires at the opposite sides thereof, said wire conductorsv extending outwardly from said tube and from position between said securing wires, and having the outermost portions terminating as unattached ends, the outermost of said three securingwires being rectangular in cross-section. the

outer two wires of said three wires of said securing means being directly against the surface of said tube.

6. Ina heat exchanger, a tube adapted to contain fluid the temperature of which is to be influenced, wire conductors on the exterior of said tube, and securing means for holding said wire conductors on said tube, said securing means comprising three wires encircling said tube and arranged side by side, and said wire conductors being in heat exchanging position on the exterior of said tube and extending between the center one of said three wires and said tube and thence between said center wire and the securing wires at the opposite sides thereof, said wire conductors extending outwardly from said tube and from position between said securing wires, and having the outermost portions terminating as unattached ends, the outermostof said three securing wires being smaller in cross-section than the diameter of the center wire of said three securing wires, the outer two wires 01' said three wires of said securing means being directly against the surface of said tube.

7. In a heat exchanger, a tube adapted to contain fluid the temperature of which is to be influenced, wire conductors on theexterior 01' said tube, and securing means for holding said wire conductors on said tube, said securing means comprising a plurality of binding elements encircling said tube and arranged side by sideand including outer members and an intermediate member positioned between said outer members. and said wire conductors being in heat exchanging position on the exterior of said tube and extending between said intermediate member and said tube and thence between said intermediate member and the outer members at the opposite sides of said intermediate member, said wire conductors extending outwardly from said tube and from position between said binding elements, the outer two wires of said three wires of said securing means being directly against the surface of said tube.

MORTON H. McTURK.

REFERENCES CITED The following references are of record in the file or this patent:

UNITED STATES PATENTS Number

Images