|Publication number||US3912004 A|
|Publication date||Oct 14, 1975|
|Filing date||Aug 2, 1974|
|Priority date||May 10, 1974|
|Publication number||US 3912004 A, US 3912004A, US-A-3912004, US3912004 A, US3912004A|
|Inventors||William J Darm|
|Original Assignee||William J Darm|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Referenced by (19), Classifications (13)|
|External Links: USPTO, USPTO Assignment, Espacenet|
HEAT EXCI-IANGER APPARATUS WITH SPACER PROJECTIONS BETWEEN PLATES Filed:
Inventor: William J. Darm, 5815 SW. Tucker Ave., Beaverton, Oreg. 97005 Aug. 2, 1974 Appl. No.: 494,170
Related US. Application Data Continuation-in-part of'Ser. No. 468,659, May 10,
1974, which is a continuation of Ser. No. 221,543, Jan. 28, 1972, abandoned.
 US. Cl 165/166; 29/1573  Int. Cl. F28F 3/10  Field of Search l65/166.7, 4 F
 References Cited UNITED STATES PATENTS 1,816,757 7/1931 White 165/166 X 1,826,344 10/1931 Dalgliesch 165/166 1,831,533 11/1931 Hubbard 165/166 2,941,787 6/1960 Ramen..... 165/166 X 3,381,747 5/1968 Darn 165/166 3,473,604 10/1969 Tiefenbache'r..... 165/166 3,719,227 11/1970 Vensscn 165/166 R17,973 2/1931 Moshcr 165/161 1 Oct. 14, 1975 Primary ExaminerCharles J. Myhre Assistant ExaminerTheophil W. Streule, Jr. Attorney, Agent, or Firm-Klarquist, Sparkman, Campbell, Leigh, Hall & Whinston A heat exchanger apparatus is described in which the heat exchanger plates are spaced apart by spacer projections formed by indentations in such plates at positions intermediate to their longitudinal edges. The heat exchanger apparatus is of the counter-flow type so that two fluids flow in opposite directions through two channels on opposite sides of each heat exchanger plate. The exchanger plates have their ends split into two ends portions which are joined to two different exchanger plates on opposite sides thereof to form two separate sets of channels. A sealing means is provided along the longitudinal edges of the heat exchanger plates, including a synthetic plastic material bonded to such edges for sealing the channels. The spacer projections maintain the exchanger plates spaced apart by a fixed predetermined distance to enable a greater pressure difference between the two fluids flowing across each plate without changing the spacing between such plates.
ABSTRACT ll Claims, 5 Drawing Figures Sheet 1 of2 3,912,004
US. Patent Oct. 14, 1975 Sheet 2 0f 2 Oct. 14, 1975 US. Patent FIG. 3
HEAT EXCHANGER APPARATUS WITH SPACER PROJECTIONS BETWEEN PLATES REFERENCE TO RELATED PATENT APPLICATION BACKGROUND OF THE INVENTION The present invention relates to heat exchanger apparatus used to exchange heat between flowing streams of fluid, including liquid or gas, of different temperatures. In particular, the heat exchanger apparatus relates to counter-flow type heat exchangers in which the two fluids flow in opposite directions on opposite sides of metal heat exchanger plates, and the spacing between such plates is maintained at a fixed, predetermined distance by spacer projections formed by indentations in the plates. These spacer projections are positioned intermediate to the two longitudinal edges of the exchanger plates and enable efficient operation of the heat exchanger over a wide range of pressure differences between the two streams of liquid or gas flowing therethrough. The heat exchanger apparatus of the present invention is particularly adaptable for use as an air-to-air heat exchanger in a building ventilating system.
Counter-flow heat exchangers have been described in U.S. Pat. No. 3,381,747 of W. J. Darm, including a plurality of separate heat exchanger plates disposed within a housing and defining two sets of channels with one channel of each set being provided on the opposite sides of a heat exchanger plate so that the two fluid streams flow in opposite directions to provide a very efficient heat exchanger operation. In this prior apparatus, the heat exchanger plates are spaced apart by spacer strips positioned at the outer edges of the plates. However, this has the disadvantage that high pressure differences between the two fluid streams cause the middle portions of the exchanger plates to bend toward and away from each other due to the pressure difference, thereby changing the spacing between plates which results in less efficient operation. A less efficient cross-flow type of heat exchanger apparatus is shown in U.S. Pat. No. 3,473,604 of E. Tiefenbacher in which the two fluids flow perpendicular to each other on opposite sides of the heat exchanger plates. In this heat exchanger, the plates are undulated and are displaced from each other A the wave length of undulation and are spaced apart by terminal bars at their outer edges which are soldered thereto at their opposite edges to form the channels. Neither of these prior heat exchangers is constructed in the simple, efficient manner of the present invention by which the heat exchanger plates have their ends split into two end portions which are joined to different heat exchanger plates on opposite sides thereof to form the two separate sets of channels. As a result, the heat exchanger apparatus of the present invention is simpler and less expensive to manufacture, and operates in a more efficient manner than previous heat exchangers.
SUMMARY OF THE INVENTION Therefore, it is one object of the present invention to provide an improved heat exchanger apparatus in which the heat exchanger plates are maintained in fixed predetermined spaced relationship to enable its use with fluids which have a high pressure difference and thereby provide a more efficient operation.
Another object of the invention is to provide such an improved heat exchanger apparatus in which the heat exchanger plates are spaced apart by a plurality of separate projections formed by indentations in the plates at intermediate positions between the two longitudinal edges of the plates in order to maintain the plate spacing at a fixed value.
A further object of the present invention is to provide such a heat exchanger apparatus which is of a counter- 7 flow type made of a simple and inexpensive construction formed by splitting the ends of the heat exchanger plates into two end portions which are joined to different heat exchanger plates on opposite sides thereof in order to form the twosets of channels for the heat exchanger fluid, so that the two fluids can flow in opposite directions on the opposite sides of a heat exchanger plate.
Still another object of the invention is to provide such a heat exchanger apparatus in which the channels are sealed by a layer of synthetic plastic sealing material bonded to the longitudinal edges of the heat exchanger plates and which may also bond the heat exchanger plates to the housing containing such plates.
BRIEF DESCRIPTION OF DRAWINGS Other objects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments thereof and from the attached drawings of which:
FIG. 1 is a perspective view showing an assembly of heat exchanger plates made in accordance with one embodiment of the invention prior to sealing such plates and mounting them in a housing;
FIG. 2 is a perspective view of a heat exchanger apparatus using a heat exchanger plate assembly similar to that of FIG. I with the heat exchanger housing broken away to show the internal construction of such apparatus;
FIG. 3 is an enlarged horizontal section view taken along the line 33 of FIG. 2;
FIG. 4 is a vertical section view taken along the line 44 of FIG. 3; and
FIG. 5 is a plan view of a portion of FIG. 2 shown on an enlarged scale.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows an assembly 10 of heat exchanger plates which may be employed in the heat exchanger apparatus of the present invention. The assembly 10 of heat exchanger plates is also referred to herein as a core element. The assembly 10 includes a plurality of corrugated or undulated heat exchanger plates l2, l4, l6, l8 and 20 which are supported in the assembly in substantial parallelism in the intermediate portions thereof between their ends. Each of the heat exchanger plates is made of sheet metal, such as aluminum, and has a length conforming substantially to the length of the heat exchanger apparatus. The corrugations of the heat exchanger plates extend transversly to the length of the plates and therefore to the path of the fluid transmitted through the heat exchanger so that such corrugations cause turbulence of such fluid which increases heat exchanging efficiency.
Each of the heat exchanger plates has both of its ends split into two end portions by a cut 22 extending longitudinally partially down the length of the plate. The two end portions of each split end of a heat exchanger plate are fastened to the end portions of different exchanger plates on opposite sides thereof by angle pieces 24 of U-shaped cross sections crimped thereto. The cut parallels the two longitudinal edges 26 and 28 of the plate and normally is made about midway between such longitudinal edges in order to divide the ends of each plate into a pair of end portions or tongue segments. For example, the lower end of heat exchanger plate 12 is split into a pair of tongue segments 12a and 12b which are of approximately equal width.
The tongue segments of each exchanger plate end are shown bent in reversedirections. Thus tongue segment 12a, as shown in FIG. 1, is bent to curve outwardly (where it will meet with the housing of the exchangers which is assembled about the core element) and tongue segment 12b below segment 12a is bent to curve inwardly. Considering exchanger plate 14, its upper tongue segment 14a is bent inwardly, whereas its lower tongue segment 14b is bent outwardly to meet tongue segment 1212. Where adjacent ends of tongue segments meet, they may be fixed together using an overlying angle piece, such as angle piece 24, secured in place as by crimping.
It will be noted that whereas the upper tongue segment 12a of plate 12 is bent outwardly, and the lower one 12b is bent inwardly, at the opposite end of the exchanger plate the upper tongue segment 120 is bent inwardly whereas the lower one is bent outwardly. This same relationship holds true for the tongue segments at each set of ends of an exchanger plate. A divider member shown at 30, including a horizontal wall expanse 32 and a vertical marginal flange 34, may be inserted into cuts forming the tongue segments, at each set of ends of the exchanger plates. The divider member, when positioned as shown in FIG. 1, serves to separate end portions of channels 36, 38, 40, 42, 44, 46 defined on opposite' sides of the various plates. Thus, and considering channel 40 in FIG. 1, the divider separates this channel where such is defined between tongue segments 18a, 16a, from portions of channels 38 and 42 below the divider, defined between tongue segments b, l8b and 16b, 14!), respectively.
As shown in FIG. 1, channels 36, 40 and 44 at the end of the assembly pictured at the bottom of FIG. 1, open to the end of the assembly above the divider. At the opposite end of the assembly, these channels open up to the end of the assembly below the divider. The reverse is true for channels 38, 42 and 46 which at the end of the assembly pictured at the bottom of FIG. 1, open to the end of the assembly below the divider, and at the opposite end of the assembly, open to the end of the-assembly above the divider.
With the arrangement, and assuming the presence of an encompassing casing, it should be obvious that one set of channels may be utilized for the passage of one body of fluid through the exchanger, and an alternating set for the passage of another body of fluid through the exchanger, with such bodies of fluid passing through multiple flow paths interspersed with each other.
In making an exchanger with a core element of the type described, and when it is remembered that typically a far greater number of exchanger plates are utilized than actually pictured in FIG. 1, it should be obvious that a problem arises with respect to positioning properly the adjacent exchanger plates where they extend in expanses between the ends of the plates. The plates usually are made of thin metal, and if corrugated transversely of'their lengths, have considerable flexibility in a transverse direction. Further, they are easily twisted. Obviously, if the plates are not properly oriented in the completed exchanger with substantially uniform spacing existing between them where they extend throughout their length, the efficiency of the exchanger is affected.
Thus, according to this invention, the various exchanger plates are arranged substantially as pictured in FIG. 1. During assembly, and to tie the various exchanger plates together, tying clips 48 which may be metal strips attachable to the edges of the plates, are assembled with the plates by fixedly attaching them to the edges of the plates at regions spaced along the length of the assembly. The clips are attached to each of the opposite sets of adjacent edges in the plate assembly. The tying clip 48 specifically illustrated has slotted depressions formed in it, the slots receiving edge portions of the plates, which may be twisted slightly after being passed through the slots to hold the clip in place. The exchanger plates are also fastened together at their ends through joinder of the tongue segments with angle pieces 24.
As shown in FIG. 2, the heat exchanger apparatus of the present invention includes a plate assembly 10' similar to that of FIG. 1 which is mounted within a sheet metal housing 50 having two sealing layers 52 of epoxy resin or other suitable synthetic plastic material covering the top and bottom portions of the housing. Each plastic sealing layer 52 is bonded to such housing and to the longitudinal edges of the heat exchanger plates, thereby sealing the channels between such heat exchanger plates and attaching such plates to the housing. If desired, the plastic sealing layers 52 may be provided with reinforcing sheets of fiberglass material.
In addition to the tying clips 48', which hold the longitudinal edges of the heat exchanger plates in spaced relationship, two sets of spacer projections 54 and 56 are at positions intermediate between the longitudinal edges 26 and 28 thereof. The spacer projections may be formed by making indentations in the troughs or crests of the undulated heat exchanger plates, such plates having their troughs and crests in alignment.
As shown in FIGS. 3 and 4, one set of spacer projections 54 is formed by projections oflarger diameter and of greater height than the other set of spacer projections 56. Thus, the height 58 of projections 54 may be many times the height 60 of projections 56. Projections 54 extend inward toward the longitudinal center line 62 of the heat exchanger plate, while projections 56 extend outwardly away from such center line. For this reason, the indentations forming the spacer projections 54 can bend the sheet metal a greater distance than can the indentations forming projections 56, without breaking such metal. For example, in order to provide an optimum spacing between adjacent heat exchanger plates of about 7/16 of an inch, spacer projections 54 project a distance from the unbent undulated heat exchanger plates approximately three times the height of projections 56 while the maximum diameter of projections 54 is about twice the maximum diameter of projections 56. As shown in FIG. 4, the projections 54 and 56 are in the form of a plurality of separate conical projections having rounded peaks.
Each of the heat exchanger plates in FIG. 3 has projections 54 and 56 extending from the opposite sides thereof into engagement with projections on the two heat exchanger plates positioned on opposite sides of such one plate. In addition, it should be noted that the large projections 54 of one plate engage the small projections 56 on the adjacent plate and vice versa. In this manner, the spacing between adjacent heat exchanger plates is maintained as substantially fixed predetermined distance regardless of the pressure of the fluids flowing through the chambers between such plates.
As shown in FIG. 2, it may be necessary to provide three horizontal rows of spacer projections between the longitudinal edges 26 and 28 of the heat exchanger plates when such plates are extremely wide and the apparatus operates with a large difference in gas pressure between the two gas streams flowing on opposite sides of such plates. However, a single horizontal row of spacer projections aligned with the divider 30 may be employed on smaller widths of the exchanger plates.
As stated previously, the longitudinal edges of successive heat exchanger plates are spaced apart and tied to one another by means of the clips 48' which extend laterally across such longitudinal edges at the top and bottom of the plates. As shown in FIG. 5 the clips 48' are slotted channel members which may be provided with a plurality of acute angle slots 64 through a U- shaped channel portion formed in the bottom of such clips. The longitudinal edges of heat exchanger plates extend into the slots 64 and are attached thereto by crimping 66 the portion of such edges extending through the slots. In this manner, a rigid heat exchanger assembly is formed before it is enclosed in the metal housing 50 and bonded thereto by the plastic sealing layer 52.
It will be obvious to those having ordinary skill in the art that many changes may be made in the details of the above-described preferred embodiment of the present invention. For example, the heat exchanger plates may be flat rather than undulating and may be provided with spacer projections only on one side thereof which engage flat portions of the adjacent heat exchanger plates. Therefore, the scope of the present invention should only be determined by the following claims.
I. A counterflow heat exchanger apparatus comprisa plurality of heat exchanger plates defining a plurality of fluiid channels disposed side by side between said plates, said plates having longitudinal edges extending between the opposite ends thereof;
a plurality of fastening means for joining the opposite ends of the exchanger plates to the ends of other exchanger plates adjacent thereto, at least some of said plates having each of their ends split into two end portions which are joined to two different exchanger plates on opposite sides thereof and separated by a divider member extending laterally to said end portions to form two separate sets of channels both of whose inlet and outlet openings are defined by said split end portions and said divider member, said two sets of channels both extending in substantially the same direction, so that fluid can flow through one set in the opposite direction to fluid flowing through the other set of channels to provide a counterflow heat exchanger;
sealing means attached to the longitudinal edges of said plates for sealing said channels; and
spacer means for spacing the exchanger plates apart, said spacer means including a plurality of separate spacer projections on the exchanger plates at intermediate positions between the two longitudinal edges of the plates, said projections on one plate extending into contact with at least one other exchanger plate so that said one plate contacts the two plates on opposite sides thereof to form each of said two sets of channels with fixed predetermined widths.
2. A heat exchanger apparatus in accordance with claim 1 in which the sealing means includes synthetic plastic material bonded to said longitudinal edges.
3. A heat exchanger apparatus in accordance with claim 2 which also includes a housing containing said heat exchanger plates and bonded to said plastic material.
4. A heat exchanger apparatus in accordance with claim 1 in which the projections extend outwardly from the opposite sides of the exchanger plate.
5. A heat exchanger apparatus in accordance with claim 4 in which the projections of each plate engage projections of the two plates on opposite sides of said plate.
6. A heat exchanger apparatus in accordance with claim 1 in which the heat exchanger plates are undulated plates having undulated portions with troughs and crests on opposite sides of a longitudinal center line, said two sets of channels both extending laterally across said troughs and crests, and said undulated plates being aligned with each other at said troughs and crests.
7. A heat exchanger apparatus in accordance with claim 6 in which the projections include a plurality of first and second projections on opposite sides of the exchanger plates formed by indentations in the crests or troughs, said first projections being formed by indentations extending toward the longitudinal center line and said second projections being formed by indentations extending away from said center line, and said first projections being of greater height than said second projections.
8. A heat exchanger in accordance with claim 4 in which the projections are annular, substantially conical first and second projections on opposite sides of the exchanger, said first projections being of greater height and greater diameter than said second projections.
9. A heat exchanger apparatus in accordance with claim I in which the spacing means includes tying clips extending transversely across the longitudinal edges of the heat exchanger plates and fixedly attached thereto to space said edges apart.
10. A heat exchanger apparatus in accordance with claim 1 in which at least some of the heat exchanger plates are undulated plates having undulated portions providing troughs and crests on opposite sides of a longitudinal center line, and the spacer projections include projections formed by indentations in the undulated portions toward the center line and which engage adjacent exchanger plates.
11. A heat exchanger apparatus in accordance with claim 10 in which the undulated plates are aligned with each other at said troughs and crests.
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|U.S. Classification||165/166, 165/DIG.388, 29/890.39|
|International Classification||F28D9/00, B23P15/26, F28F9/007|
|Cooperative Classification||Y10S165/388, F28D9/0037, B23P15/26, F28F9/0075|
|European Classification||F28D9/00F2, F28F9/007A, B23P15/26|