US2751199A - Heat exchanger - Google Patents

Description

June 19, 1956 B. s. WILLIAMS 2,751,199

HEAT EXCHANGER Filed April 18, 1951 3 Sheets-Sheet 1 INVENTOR. Fi 5 2/ fiUKDELL 6 Mum/vs WyM June 19, 1956 B. s. WLLIAMS 2,751,199

HEAT EXCHANGER Filed April 18, 1951 3 Sheets-Sheet 2 INVENTOR. B wELL J. Mum/ms June 19, 1956 B. s. WlLLlAMS HEAT EXCHANGER 3 Sheets-Sheet 3 Filed April 18, 1951 INVENTOR Bunk/1 Ff/Jams BY WM jnyflwl ATTORNEY United States Patent HEAT EXCHANGER Burdell S. Williams, Larchmont, N. Y., assignor, by mesne assignments, to Taco Heaters, Incorporated, Cranston, R. 1., a corporation of New York Application April 18, 1951, Serial No. 221,665 9 Claims. (Cl. 257--184) This invention relates to heat exchangers and finned tubes therefor; particularly to tubes having removable fins and having liquid metering arrangements in conjunction therewith.

In the prior art, heat exchangers with finned tubes have been made but they usually have been difiicult to clean and have not been arranged to distribute properly the fluids involved over the heat exchange surfaces. This especially is true of heat exchangers used for cooling viscous fluids such as oil. It is to be understood, however, that the present invention can be used for both cooling and heating purposes.

Frequently, when a cooling problem is involved, it is desirable to arrange the cooling surfaces so that the speed of at least one of the liquids over the heat exchange surface will vary with the viscosity and this is difiicult to accomplish in prior heat exchangers, especially with the conventional shell and coil or tube type. In such a shell and coil or tube heat exchanger, the volume of liquid required to be pumped therethrough will be greater than that of a comparable size heat exchanger made in accordance with the present invention. As a result, larger pumps and motors are required with prior art devices as compared with the invention herein. Conventional shell and coil or tube heaters are difiicult to clean and tend to clog as the viscosity of the fluid increases because of temperature reduction of the fluid. A conventional shell and tube heat exchanger is particularly liquid has solid material therein which will deposit on the surfaces or settle at inaccessible places in the exchanger. It has been found that additional tube surface must be provided so as to have the viscous liquid to be cooled.

One of the objects of the present invention is to provide an improved heat exchanger which can be cleaned with ease.

unsatisfactory when the proper surface area for the Another of the objects of the invention is to provide a heat exchanger particularly useful in cooling a viscous liquid and having an improved liquid distributing means and effect.

A still further object of the invention is to provide an improved heat exchanger finned tube construction arranged so that the fin can be easily assembled thereon and so as to maintain contact with the tube wall regardless of expansion and contraction of the tube.

A further object of the invention is to provide a heat exchanger having a substantially continuous relatively thin film of liquid in contact with the heat exchange surface.

Another of the objects of the invention is to provide a heat exchanger wherein the largest quantity of liquid will be in contact with the cooling surface where the cooling surface is most effective and will become gradually thinner as the surface becomes less effective due to higher temperature on the portions of the fin remote from the tube itsel In one aspect of the invention, the radial fins for the Patented June 19, 1956 tubes can be made by wrapipng a formed sheet metal strip around the tube and using yieldable clamps at spaced points along the strip so as to hold it in place. The flat metal strip is formed so as to provide the desired configurations of the fins on the tube.

In one embodiment of a heat exchanger of the invention, the tubes can be placed in an approximately vertical parallel arrangement with their upper ends c0operating with suitable apertures in a tube sheet of the heat exchanger. The fluid to be passed over the tubes and fins is fed to the tube sheet trough or compartment so that it will be distributed to the various tubes. A liquid distributing or liquid metering means is located over the fins and either in or adjacent said apertures in the tube sheet. The metering means will distribute and direct the liquid over the tubes. The ends or interiors of the tubes can be suitably connected with the heat exchange fluid, such as the coolant, if the exchanger is used for cooling purposes.

In a preferred embodiment, the metering means is in the form of a radial fin collar which can be formed from flat sheet metal and wrapped around the tube. Preferably, it protrudes through an aperture of the tube sheet into the inlet trough or incoming liquid compartment. The number and arrangement of fins of the distributing or metering means can be properly related to the radial cooling fin means on the tube. The liquid will flow down the outer surfaces of the metering means and will be directed into the space between the tube wall and interior of the fins, the liquid flowing in a downward direction against the tin. The liquid also is directed into the V- shaped portions of the exterior face of the fins and a thin film will be on the relatively flat part of the outside face.

the viscosity of the liquid increases, it will not flow as fast through the area between the outer faces of the metering devices and the edges of the apertures so that the height or head of liquid on the tube sheet will increase. This will continue until the tops of the metering devices are reached by the liquid at which time liquid will also flow down the interior faces of the metering means. The inside passages of the metering means carries fluid to both the inside and outside of the fin surfaces. Some of the aspects of the invention can be applied to horizontal as well as vertical heat exchangers. The shapes of the V passages of the metering means and location thereof relative to the fin passages can be varied so as to direct liquid as desired. The liquid directed to the interior space between the fins and tube sur face will be confined as it passes down.

These and other objects, advantages, and features of the invention will become apparent from the following description and drawings which are merely exemplary.

in the drawings:

Figure l is a perspective view of one form of heat exchanger employing the tubes of the present invention, the front and top covers being removed.

Figure 2 is an enlarged sectional view of a heat exchanger generally similar to that of Figure 1.

Figure 4 is a reduced fragmentary view of the upper end of a tube showing the metering means and the tube sheet relationship.

Figure 5 is a perspective lower end view of one form of tube and fin.

Figure 6 is a schematic view of one device using the invention.

Figure 7 is a perspective view partly broken away showing another embodiment of the invention.

FigureS isa side elevation of still another embodiment of the invention.

Figure 9 is a plan view of the embodiment shown in Figure 8.

The heat exchanger or liquid temperature controller illustrated in Figure 1 may have an outside casing 10 with a liquid distributing trough 11 at the upper ends of the bundles of tubes 12. A liquid distributing inlet means 13 can be arranged to distribute liquid to trough 11. The upper ends of the tubes may be connected together by suitable U or return bend pipes 14. The bottom ends of the tubes are connected together as desired by return bend tubes 15. The liquid inlet and outlet pipes 16, 17 may be suitably arranged to feed heat exchange liquid to the interiors of the tubes. The heat exchange liquid may be, for example, a coolant, which is fed to pipe 16 and returned by pipe 17.

The liquid flowing down the tubes will be collected in pan 18A. Radial fin means 19, described in detail hereafter, are provided for the tubes. metering means 24 is provided at the top tubes as will be described later.

A heat exchanger, somewhat similar to that seen in Figure l, is illustrated in section in Figure 2. This exchanger is suitable particularly, for example, for use as a cooling means for machine tool oil, or the like, but can be used for other purposes, cooling or heating. Similar parts have been given the same reference numerals as in Figure 1. Case 10 has a tapered portion 10A at the bottom thereof leading to pan 18A. Pan 18A has an outlet opening 28. Liquid inlet 29 feeds the oil or other liquid to be cooled to the distributing trough 11, said trough having a tube sheet therein. Tubes 18 have return bends l4 and 15 connecting the same as desired with each other and with the inlet and outlet pipes 16 and 17, which in this instance will be the refrigerant or cooling fluid. A screen can be used to strain out foreign matter if needed. Liquid distributing or metering means 24 extend upwardly through apertures 25A in the tube sheet 25, the apertures being only slightly larger than the outside diameter of metering means 24.

The radial fins 19 can be made of brass, steel, aluminum, or any material having the desired heat conductivity and corrosion resistance. The fins may be of different material than the tubes. Preferably, a flat piece of metal has corrugations formed therein similar to the channel-like structure shown. The strip then is wrapped around the tube, the ends 19A being brought together in overlapping relationship. Spring or yieldable means or clips 22 then are expanded and slipped into place over the fin. Upon release, the clips or holding means 22 will firmly hold the fins in place on the tube, the inner portions of the fins being in firm heat transferring contact with the tube. The yieldable means will permit expansion and contraction of the tube without changing the effective heat transferring contact between the fin and tube. Also, if the fluid should freeze, the tube can expand without damage. One type of suitable yieldable means is a form similar to one variety of automobile hose clamp. In order to release this, the ends 23 can be squeezed together with a suitable tool so as to enlarge the opening in the circular portion of the clip. Other types of suitable yieldable means or clips can be used. The important aspect is that the clips firmly hold the fin in contact with the tube at all times. The clips are illustrated in Figure 1 but most of them have been omitted in Figure 2 for clarity.

At the upper end of a tube, a distributing or liquid metering member 24 can be formed from a strip of metal and wrapped around the tube and suitably held in assembled relationship thereon. A clamp (not shown) can be used, the ends locked together, or the margins of the aperture in the tube sheet depended upon to hold the distributing'means 24 in position. Tube sheet 25 (Figs. 2, 4) is arranged to receive liquid 26, said liquid flowing into contact with the fins '27 (Figs. 2, 3) of the distributing of each of the A liquid distributing or member 24. The distributing fins 27 will cause the liquid to flow downwardly over the various heat transfer fins on the tube 18.

As mentioned previously, the liquid will flow between the tube wall and the inside of the fins. It also will flow on the outside thereof including the relatively flat outer part. Thus, the entire fin surfaces will be wet, the larger quantity of the liquid being where the most elfective part of the cooling surface is located adjacent the tube wall. The film becomes gradually thinner as the surface becomes less efiective.

in the event that the liquid 26 is flow is too great, it will not be able to flow downwardly over the outside of distributor 24 with sufficient rapidity and thus the height or head of the liquid in the trough 11 or on the tube sheet 25 will rise until the liquid reaches the top 28 of the metering means at which time it also will fiow downwardly on the inner faces of the distirbutor, thereby substantially doubling the volume of liquid.

As an example of one type of use, heat exchanger 35 (Fig. 6), similar to that of Fig. 2, can have the oil operating lines A and B of machine tool 36 connected thereto. Refrigerating unit 37 is connected with the tubes of heat exchanger 35 so as to cool the oil therein. A suitable thermostat can be inserted in the liquid being cooled so as to control operation of the refrigerating unit. In the case of machine tools, it is very important to keep the oil at a suitable temperature because if it is allowed to heat, the parts will expand undesirably as the machine is operated and thus seriously affect accuracy. Also, other desirable operating advantages can be obtained by keeping the oil at predetermined temperatures.

As another aspect of use, some of the tubes of the heat exchanger can be connected to the refrigerating apparatus. In some instances, an automatic machine tool will employ several circuits using different oils or fluids which should be maintained at temperatures related to each other. The other stream of oil in such a case can be connected to the interior of other tubes of the heat exchanger and this latter fluid will be controlled by the temperature of the liquid flowing over the outside of all of the'tubes.

As the radial fins become corroded or worn by chemical action, electrolysis, etc., they can be replaced with ease. The tubes and fins can be cleaned in place with ease by merely raising the metering means. If more extensive cleaning is necessary, the clips 22 can be removed and then the radial fins taken off. If it is desired to have fins of differing material, thickness, length, etc., they can be altered at any time without substantially afieeting the primary part of the heat exchange surface. Preferably, a portion of the planes of the metering fins will permit oil to flow on either side of the radial fins. This can be accomplished by having the planes of the metering fins cross the main radial fin planes.

Other types of distributing or metering means can be used. For example, as shown in Figures 7 to 9, spheres 40 can be located in the channel openings between radial fin means 19 just below or adjacent the tube sheet 25 of the liquid distributing trough for distributing liquid falling thereon uniformly over the tin means surface. The spheres may be mounted in assembled relation on a circular resilient rod 41 which fits tightly around the'outer surfaces of the radial fin means. In conjunction therewith, a further form of liquid metering device could be in the shape of a cup-like member formed by a plate 42 having four radial extending grooves 43 which rest on the tube sheet 25. in another form, the metering means may take the shape of a coiled wire 44 which is disposed in the liquid distributing trough over the radial fin means 19 in surrounding relation to the tube 18.

Where the terms fluid and liquid are used herein, it is understood that they are to be considered to be interchangeable where it is appropriate, for example, the

highly viscous or the medium employed Within the tubes for cooling or heating purposes.

It is to be understood that the details of construction can be changed without afiecting the scope of the invention except as defined in the appended claims.

What is claimed is:

1. In a heat exchanger finned tube arrangement, the combination including a tube, shaped sheet means wrapped around said tube and forming heat transfer radial fin means, yieldable clip means removably holding said fin means firmly in assembled relationship on said tube and in direct contact therewith, a removable finned liquid metering means on said tube adjacent the end of said heat transfer means where liquid first passes, said distributing means being adapted to distribute liquid over said fins and exterior wall surface of said tube, the largest quantity of liquid being directed to the most efiective heat transfer portions of said tube and fin.

2. In a heat exchanger finned tube arrangement, the combination including a tube, heat transfer means having a plurality of longitudinally extending radial channel fins, yieldable clip means removably holding said fin means firmly in assembled relationship on and in direct contact with said tube, a removable finned liquid metering means on said tube adjacent the end of said heat transfer means where liquid first passes, said distributing means being adapted to distribute liquid over said fins and through said channels and exterior wall surface of said tube, the largest quantity of liquid being directed to the most effective heat transfer portions of said tube and fin.

3. In a heat exchanger, the combination including a tube, radial fin means extending longitudinally along said tube, liquid inlet means having a passage therethrough adjacent one end of said radial fin means, and a finned distributing means adjacent said liquid inlet means distributing liquid passing through said passage onto said fin means and tube, said distributing means directing the largest quantity of liquid onto the most eflective heat transfer portions of said tube and radial fin means.

4. In a heat exchanger, the combination including an inlet liquid tube sheet means having an aperture therethrough, a vertical tube having a portion extending through said aperture, heat transfer fin means around said tube having a plurality of vertically extending radial fins, removable finned liquid metering means on said tube adjacent said aperture receiving liquid therefrom and directing it onto said tube and fins.

5. In a heat exchanger, the combination including an inlet liquid tube sheet means having an aperture therethrough, a vertical tube having a portion extending through said aperture, heat transfer fin means around said tube having a plurality of vertically extending radial fins and channels, removable finned liquid metering means on said tube adjacent said aperture receiving liquid therefrom and directing it onto said tube, fins, and through said channels.

6. In a heat exchanger, the combination including a casing, an inlet liquid trough means in said casing, said trough having a plurality of apertures therein, a plurality of vertical tubes having portions extending through said apertures, vertically extending radial fin means on said tubes below said trough means, finned liquid metering means on said tubes in said apertures and extending into said trough, said metering means directing liquid onto said tubes and fins, means adjacent the bottoms of said tubes collecting the liquid flowing thereover, and means connecting the interiors of said tubes to a heat exchanger fluid.

7. In a heat exchanger, the combination including a casing, an inlet liquid trough means in said casing, said trough having a plurality of apertures therein, a plurality of vertical tubes having portions extending through said apertures, vertically extending radial channel fin means on said tubes below said trough means, removable finned liquid metering means on said tubes in said apertures and extending above the lower face of said trough, said metering means directing liquid onto said tubes, fins, and through said channels, means adjacent the bottoms of said tubes collecting the liquid flowing thereover, and means connecting the interiors of said tubes to a heat exchanger fluid.

8. In a heat exchanger, the combination including a casing, an inlet liquid trough means in said casing, said trough having a plurality of apertures therein, a plurality of vertical tubes having portions extending through said apertures, vertically extending radial channel fin means wrapped around said tubes below said trough means, yieldable clip means removably holding said fin means in place, removable finned liquid metering means on said tubes in said apertures and extending into said trough, said metering means directing liquid onto said tubes, fins, and through said channels, means adjacent the bottoms of said tubes collecting the liquid flowing thereover, and means connecting the interiors of said tubes to a heat exchanger fluid.

9. In a machine tool oil cooler apparatus, a heat exchanger having tubes with longitudinally extending radial fins removably wrapped around each tube, yieldable clip means holding said fins in place, a liquid inlet means having a passage therethrough adjacent one end of said radial fins, removable metering means on said tubes adjacent said liquid inlet means distributing liquid passing through the passage over said tubes and fins, a cooling supply means connected to said tubes, and means feeding liquid to be cooled to and from said tool and over said heat exchanger tubes and fins.

References Cited in the file of this patent UNITED STATES PATENTS 473,876 Hodges et al. Apr. 26, 1892 1,639,857 Planski Aug. 23, 1927 1,655,273 Kelley Jan. 3, 1928 1,721,808 Kettering July 23, 1929 1,874,458 Cornell Aug. 30, 1932 1,942,211 Hartwig Jan. 2, 1934 2,190,584 Feldmeier et a1 Feb. 13, 1940 2,200,355 Cornell May 14, 1940 2,238,924 Bennett Apr. 22, 1941 2,296,946 Olstad et al Sept. 29, 1942 2,605,620 Taylor Aug. 5, 1952 FOREIGN PATENTS 360,245 Germany Sept. 30, 1922

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