US2281207A - Method of manufacturing heat exchange devices - Google Patents

Description

L@ ev P. F. scHoEN LLT- "KTQ

METHOD OF MANUFACTURING HEAT EXCHANGE DEVICES Original Filed June 17, 1959 `\`\SS.\`S

April 28, 1942.

Patented Apr. 28, 1942 2,281,207 y ICE.

METHOD F MANUFACTURING HEAT EXCHANGE DEVICES Paul F. Schoen, Dearborn, Mich., assignor to Bohn Aluminum & Brass Corporation, Mich., a corporation of Michigan Detroit,

Original application June 17, 1939, Serial No.

Divided and this application February 1, 1940, Serial N0. 316,803

1 Claim.

This invention relates to a method of manufacturing heat exchange devices.

A primary object of the invention is to provide a structure of improved economy and efficiency, and this object is accomplished by construction of the heat exchanger from tubing extruded from aluminum or other suitable material. 'I'he vci tubing is extruded with iins on both the innerl and outer diameters, and the tubing is twisted to give the fins a spiral form, which increases the heat-exchange eiciency and improves the physical properties of the tubing. If the tubing is to be bent in forming a heat-exchange unit, the part to be bent is kept in more pliable condition by not twisting it, and the external ns are removed prior to bending.

These and other objects and advantages of the invention will become apparent as the description proceeds.

While preferred forms of the invention are disclosed herein for purposes of illustration, Various changes may be made in the method without departing from the spirit of the invention as herein set forth and claimed.

This application is a division of my application Serial No. 279,690, filed June 17, 1939, which claims the article resulting from the method.

In the drawing:

Fig. 1 is a plan view of a heat exchange device l embodying the invention.

Fig. 2 is a section on line 2--2 of Fig. 1.

The invention is illustrated in connectionY with a unit for application to a wall or ceiling of a cold storage room, although obviously the novel features may be used in heat exchange devices for other purposes.

The cooling unit illustrated consists of a single length of tubing I0, which is extruded with a plurality of externall ns II and with a plurality of internal ns I2. This tubing is preferably extruded from commercially pure aluminum, although other suitable materials may be used.

At places where the tubing is to be bent, such as at I3, the outer fins are sheared off to prevent any interference with the bending operation.

As the result of the extruding operation, the flns II and I2 are originally alined with the longitudinal axis of the tubing. In order to give the ns of the tubing a spiral shape the length of the tubing to be spiraled, for example the straight run I4, is twisted while under tension. This is preferably done by applying clamps to the outside of the tube at the points I5 and I6, and rotating one of the clamps while pulling it away from the other clamp. This operation maintains the tube preferably straight and gives an even and uniform spiral shape to the iins, the pitch of the spiral depending on the number of turns given to the movable clamp.

The run I4 is preferably twisted while the entire piece I0 is a straight length, and it is to be understood that'this first twisting operation does not twist the tube beyond the point I6, -so that the internal iins at the place I3 have not been spiraled.

'I'he next operation is to bend the tube at the place I3. Inorder to prevent collapse of the tube and of the internal ns a mouse formed of a plurality of exible elements, such as Wires. is drawn into the tubing to the place I3, and the tube is then bent in the desired direction.

The next run I5' of the tubing is then spiraled, and the bend I1 is next formed, these operations being repeated until the unit illustrated is formed. As an alternative method the different runs of the tubing can be spiraled While the tubing I0 is in one straight piece if suitable arrangements are made to keep the sections where the bends are to be made in their original un twisted condition. l

The external flns areremoved at the ends I8 and I9 in order to provide a smooth tubeadapted for connection with the tubing of a refrigeration system. The internal fins may also beremoved at the ends I8 and I9 if desired.

Among the advantages of the above construction are the fact that the twisting of the tube to spiral the iins elongates the edges of the ns, which were extruded as thin as possible, thus thinning them and increasing their eflciency for heat conduction. At the same time the tubing itself is shortened and thickened, thus increasing the safety factor on the tube. 'I'he spiral fins serve as very stili ribbing against bending of the tube sections, and the bending of the ns in spiraling serves to cold-work the fins, increasing their hardness against external damage.

'I'he spiral tins make very eflicient contact with air currents, since air moving across the ltube is directed around the spiral iins, making wiping contact with the tube and the ns. The spiral shape of the ns avoids any pockets in which condensation might collect.

The runs I4, I 5, etc., need not be parts of a single tube, but can be separate pieces connected together or to a header by suitable fittings.

I claim:

The method of producing a heat exchange device which comprises extruding a length of tubing having internal and external longitudinal fins, giving the nson certain parts of the tub'- ing a spiral form relative to the tubing, removing the external fins from the ends of the tubing and from certain parts intermediate the ends,l

and bending the tubing at said intermediate i,

parts.

' PAUL F. SCHOEN.

Images