CN101963473B - End cover and heat exchanger with same - Google Patents

Abstract

The invention discloses an end cover, which is used to close a header of a heat exchanger. The end cover defines a first end and a second end in its length direction, and the end cover is stepped so that the end cover There are at least two lengths and include an upper step with a minimum length and a lower step with a maximum length. The invention also discloses a heat exchanger with the above-mentioned end cover. According to the end cover and the heat exchanger with the end cover of the present invention, the stress on the outermost heat exchange tube of the heat exchanger can be reduced, and the burst strength of the outermost heat exchange tube can be improved, thereby improving the strength of the entire heat exchanger. burst strength.

Description

End cover and heat exchanger having the same

technical field

The invention relates to an end cap for closing a header of a heat exchanger and a heat exchanger with the end cap. the

Background technique

Heat exchangers are commonly used devices in refrigeration systems, for example, they can be used as evaporators or condensers in refrigeration systems. A conventional heat exchanger generally includes two headers arranged roughly in parallel, heat exchange tubes connected between the two headers, and fins arranged between adjacent heat exchange tubes. The end of the collector is usually sealed with an end cap, and the traditional end cap is usually in the form of a circular plate with a flange formed on the outer periphery of one side of the circular plate. the

The pressure burst strength of the heat exchanger is a main index that affects the life of the heat exchanger and measures the performance of the heat exchanger. Therefore, improving the burst strength of the heat exchanger is an important direction for the research and development of the heat exchanger. the

Contents of the invention

The present invention is based on the inventor's discovery of the fact that when the heat exchanger is subjected to a pressure burst test, the inventor unexpectedly finds that most of the damage points of the heat exchanger are on the first heat exchange tube on the outermost side, and The failure pressure of the heat exchanger is much lower than that of a single heat exchange tube. The inventor has learned through research and analysis that when a single heat exchange tube is subjected to a failure pressure test, the force on the heat exchange tube is only the pressure in the hole of the heat exchange tube, and in the heat exchanger, due to the end of the heat exchanger The cover is also affected by the internal pressure, so that the heat exchange tube is not only affected by the pressure in the heat exchange tube hole, but also by the pulling force of the part of the header that is in contact with the heat exchange tube. The closer to the end cover, the stronger the pulling force, so the first heat exchange tube is most likely to be damaged, so the end cover has an impact on the blast strength of the heat exchanger. the

An object of the present invention is to propose an end cap for closing a header of a heat exchanger which can increase the burst strength of the heat exchanger and thereby increase the service life of the heat exchanger. the

Another object of the present invention is to propose a heat exchanger having the above-mentioned end covers. the

An end cover according to an embodiment of an aspect of the present invention is used to close a header of a heat exchanger, the end cover defines a first end and a second end in its length direction, and the end cover extends into the The part inside the header is stepped with at least two lengths in the length direction of the header, and the part of the end cap protruding into the inside of the header includes an upper step with a minimum length and a The lower step portion of the maximum length, the first end surface of the lower step portion constitutes the first end surface of the end cover, the first end surfaces of the upper step portion and the lower step portion face the inside of the header, the Second end faces of the upper and lower steps face away from the interior of the header. the

According to the end cover of the embodiment of the present invention, the stress on the outermost heat exchange tube of the heat exchanger can be reduced, and the burst strength of the outermost heat exchange tube can be improved, thereby improving the burst strength of the entire heat exchanger. the

In addition, the end cap according to the embodiment of the present invention can also have the following additional technical features:

Optionally, the end cap is made of a truncated cone or a cylinder with a rectangular or square cross-section. the

Preferably, the end cap is made of a cylinder. the

The end cap is in the shape of a single step formed by an upper step and a lower step. the

The second end surfaces of the upper step portion and the lower step portion are flush and constitute the second end surface of the end cover, and the end cover is formed with a hollow cavity opened at its second end. the

A through hole is formed on the first end wall of the lower step portion. the

A boss is formed on the first end wall of the lower step in the hollow cavity, and the through hole passes through the boss. the

A flange extending radially outward is formed on the outer periphery of the second end of the end cap, and the outer periphery of the flange is integrally provided with a flange extending toward the first end of the end cap. the

A heat exchanger according to an embodiment of another aspect of the present invention includes: a first header; a second header; and heat exchange tubes, and the two ends of the heat exchange tubes are respectively inserted into the first and second headers to connecting the first and second headers; fins, the fins are respectively arranged between adjacent heat exchange tubes; and an end cover, the end cover is the end cover according to the first aspect of the present invention, Wherein the end cover is arranged in one end of at least one header to close the one end, the upper step of the end cover is adjacent to the connection between the heat exchange tube and the at least one header and the lower step is away from the connection. the

Preferably, the lower step portion of the end cover extends in the axial direction of the at least one header beyond the outermost heat exchange tube adjacent to the one end or is flush with the outermost heat exchange tube. the

According to the heat exchanger of the embodiment of the present invention, the bursting strength is improved, and the service life is improved. the

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. the

Description of drawings

The above-mentioned and/or additional aspects and advantages of the present invention will become apparent and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is the three-dimensional schematic view of the end cap according to the first embodiment of the present invention;

Fig. 2 is the axial sectional view of end cap shown in Fig. 1;

Fig. 3 is the right side view of end cap shown in Fig. 1;

Fig. 4 is the axial sectional view of the end cap according to the second embodiment of the present invention;

Fig. 5 is the axial sectional view of the end cap according to the third embodiment of the present invention;

Figure 6 is an axial sectional view of an end cap according to a fourth embodiment of the present invention;

Fig. 7 is the three-dimensional schematic view of the end cap according to the fifth embodiment of the present invention;

Figure 8 is an axial sectional view of the end cap shown in Figure 7;

Fig. 9 is a schematic perspective view of an end cap according to a sixth embodiment of the present invention;

Figure 10 is an axial sectional view of the end cap shown in Figure 9;

11 is a schematic diagram of an end cap having a rectangular cross-section according to an embodiment of the invention;

Figure 12 is an axial sectional view of the end cap shown in Figure 11;

Fig. 13 is the axial sectional view of the end cap according to the seventh embodiment of the present invention;

Figure 14 is a right view of the end cap shown in Figure 13;

Figure 15 is an axial sectional view of an end cap according to an eighth embodiment of the present invention;

Figure 16 is a right view of the end cap shown in Figure 15;

Figure 17 is a schematic diagram of a heat exchanger according to a first embodiment of the present invention;

Figure 18 is a schematic diagram of a heat exchanger according to a second embodiment of the present invention;

Figure 19 is a schematic diagram of a heat exchanger according to a third embodiment of the present invention;

Figure 20 is a schematic diagram of the force of the header of the heat exchanger according to an embodiment of the present invention;

Figure 21 is a schematic diagram of the force of the end cover of the heat exchanger according to the embodiment of the present invention;

Figure 22 is a schematic diagram of a heat exchanger with conventional end caps;

Figure 23 is a sectional view of a conventional end cap;

Figure 24 is a schematic diagram of the force of a header of a heat exchanger with a conventional end cap; and

Fig. 25 is a schematic diagram of the force of a traditional end cap. the

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention. the

In the description of the present invention, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", " The orientations or positional relationships indicated by "top", "bottom", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention rather than requiring that the present invention must be based on a specific orientation construction and operation, therefore, should not be construed as limiting the invention. the

The present invention is based on the inventor's following discovery: when carrying out the pressure burst test on the heat exchanger, it is found that most of the damage points of the heat exchanger are on the outermost first heat exchange tube, and the failure pressure of the heat exchanger Much lower than the failure pressure of a single heat exchange tube. the

The inventor has learned through research and analysis that when a single heat exchange tube is subjected to a failure pressure test, the force on the heat exchange tube is only the pressure in the hole of the heat exchange tube, and in the heat exchanger, due to the end of the heat exchanger The cover is also affected by internal pressure, so that the heat exchange tubes are not only affected by the pressure in the holes of the heat exchange tubes, but also by the pulling force of the part of the header that is in contact with the heat exchange tubes. The closer to the end cap, the stronger the pulling force, so the first heat exchange tube is most likely to be damaged. the

Figure 22 shows a schematic view of a conventional heat exchanger 100' with a conventional end cover 5', Figure 23 shows a conventional end cover 5', and Figure 24 shows a schematic view of a heat exchanger 100' with an end cover 5'. A schematic diagram of the force of the header 3'; and Figure 25 shows a schematic diagram of the force of the end cap 5'. the

As shown in Figures 22-25, a conventional heat exchanger 100' includes a first header 1', a second header 2', heat exchange tubes 3', fins 4', and end covers 5'. The two ends of the heat exchange tubes 3' communicate with the first header 1' and the second header 2' respectively, the fins 4' are respectively arranged between the adjacent heat exchange tubes 3', and the end caps 5' are used for The ends of the first header 1' and the second header 2' are closed. In Fig. 22 an end cap 5' closing the right end of the first header 1' is shown. As shown in Fig. 23, the end cap 5' is a circular plate and the outer peripheral edge of the right side is provided with a convex edge, the diameter of the end cap 5' is D', and the length is L'. As shown in Figure 22, when the end cover 5' is installed in the first header 1', the end cover 5' is located outside the rightmost outer heat exchange tube 3', for example, the right end surface of the end cover 5' is in contact with the first header 1'. When the right end surface of a header 1' is flush, L' is smaller than the distance M' between the outermost heat exchange tube 3' and the right end surface of the first header 1'. the

Below with reference to Fig. 24 and 25 analysis the stress of the header (with the first header 1 ' of the first header 1 ') and end cover 5 ' of traditional heat exchanger 100 '. the

Analyze the section from the contact surface (section) between the first header 1' and the right outermost heat exchange tube 3' to the right end of the first header 1' and the end cover 5'. the

As shown in Figures 24 and 25, σ1' is the tensile stress on the header 1' at the cross-section; S1' is the contact area between the header 1' and the heat exchange tube 3' at the cross-section; S2' is the cross-section The area minus the area of S1'; τ1' is the shear stress of the end cover 5' on the header 1'; S3' is the contact area between the end cover 5' and the header 1' (equal to the outer circumference of the end cover 5' area); S4' is the stress area at the bottom of the end cover 5; P' is the internal pressure of the header 5;

Therefore, the tensile force on the heat exchange tube 3' at the cross section is σ1'×S1';

Where σ1’×S1’+σ1’×S2’=τ1×S3’=P’×S4’

Therefore, the outermost heat exchange tube 3 ′ assembled on the heat exchanger 100 ′ is subject to a large tensile force, and the burst strength of the outermost heat exchange tube 3 ′ is reduced, thereby reducing the bursting of the entire heat exchanger 100 ′. strength. the

An end cap for closing a header of a heat exchanger according to an embodiment of the present invention will be described below with reference to the accompanying drawings. the

For ease of description, a heat exchanger 100 having an end cover according to an embodiment of the present invention is first briefly described with reference to FIG. 17 . As shown in FIG. 17 , the heat exchanger 100 includes a first header 1 , a second header 2 , heat exchange tubes 3 , such as flat tubes, fins 4 and end caps 5 . the

The two ends of the heat exchange tube 3 are respectively inserted into the first header 1 and the second header 2 to connect the first header 1 and the second header 2. 4 fins are respectively arranged on the adjacent heat exchange between tubes 3. An end cap 5 is provided in one end of at least one header for closing said one end. In the example shown in Fig. 17, only one end cap 5 closing the second end (right end in Fig. 17) of the first header 1 is shown. In the following description, the end cap 5 closing the right end of the first header 1 is also taken as an example for description. the

As shown in Figures 1-3, the end cap 5 for closing the header of the heat exchanger 100 according to the embodiment of the present invention defines a first end (Figure 2 The left end in ) and the second end (the right end in FIG. 2 ), the end cap 5 is stepped, so that the end cap 5 has at least two lengths and includes an upper step 51 with a minimum length and a lower step with a maximum length 52. the

In the first embodiment shown in FIGS. 1-3 , the end cap 5 is made of a cylinder with a diameter D and has a single step consisting of an upper step 51 and a lower step 52 , wherein the upper The step portion 51 has a first length L1, and the lower step portion 52 has a second length L2, and the length L2 of the lower step portion 52 can be regarded as the length of the end cap 5 . The upper step portion 51 has a first end surface 511 , the lower step portion 52 has a first end surface 521 and an upper surface 522 , wherein the second end surfaces of the upper step portion 51 and the lower step portion 52 are also the second end surface 53 of the end cover 5 . the

It should be understood that the present invention is not limited thereto. For example, the end cap 5 may be formed of a columnar body with a rectangular or square cross-section, and may have multiple steps to accommodate headers with a rectangular or square cross-section, such as Figures 11 and 12 show. In addition, the end cover 5 may also have a truncated cone, such as a truncated cone, thereby facilitating the installation of the end cover 5 into the header of the heat exchanger. It should be noted that when the end cover is a truncated cone, the end cover 5 The gap between the lower part and the collector can be filled with solder during welding, that is to say, the end cap 5 in the form of a truncated cone forms a columnar body with the solder, for example, when the end cap 5 is a truncated cone, the end The cap 5 forms a cylinder together with the solder. the

Next, with reference to FIG. 17 and FIGS. 20 and 21 , the stress situation of the end cap 5 will be analyzed. Similar to analyzing the force of the traditional heat exchanger 100' and the end cover 5', intercept the contact surface (section) between the outermost heat exchange tube 3 on the right and the first header 1 to the right end of the first header 1. A section of the first header 1 and the end cover 5 are subjected to stress analysis. the

As shown in Figures 20 and 21, σ2 is the tensile stress on the cross-section of the first header 1, S1 is the contact area between the first header 1 and the heat exchange tube 3 at the cross-section, and S2 is the reduction of the cross-sectional area. The area minus S1, τ2 is the shear stress of the end cover 5 on the first header 1, S5 is the contact area between the upper step 51 of the end cover 5 and the first header 1 and the contact area between the lower step 52 and the upper step The sum of the contact area of the part corresponding to 51 and the first header 1 (in other words, S5 is the contact area between the end cover 5 and the first header 1 minus the portion of the lower step 52 longer than the upper step (L2- L1) the contact area with the first header 1); S4 is the axially stressed area of the bottom of the end cover 5 (that is, the area of the first end surface of the end cover 5, including the area of the left end surface of the upper step portion 51 and the area of the lower surface The area of the left end surface of the step portion 52), S6 is the contact area between the end cover 5 and the first header 1 (that is, the outer circumference area of the end cover 5 is equal to the outer circumference area of the upper step portion 51 and the outer circumference area of the lower step portion 52 The sum of the circumferential areas), P is the internal pressure in the first header 1, where:

The tensile force on the heat exchange tube 3 is σ2×S1;

Among them, σ2×S1+σ2×S2=τ2×S5

P×S4＝τ2×S6

Since the length L2 of the lower step portion 52 of the end cover 5 is greater than or equal to the distance M from the center of the right outermost heat exchange tube 3 to the right end surface of the first header 1, S5<S6, (σ2×S1+σ2× S2)<P×S4 From this we can get: (σ2×S1+σ2×S2)<(σ1×S1+σ1×S2),

Therefore, the tensile force on the cross-section of the heat exchange tube 3 is: σ2×S1<σ1×S1. Compared with a heat exchanger with a traditional end cover, in the heat exchanger 100 with the end cover 5 according to the embodiment of the present invention, the tensile force on the heat exchange tube 3 is reduced, so the burst strength of the outermost heat exchange tube 3 is reduced. It is effectively improved, the blasting strength of the whole heat exchanger 100 is improved, and the service life is prolonged. the

As shown in Figure 2, in some embodiments of the present invention, the angle α between the first end surface 511 (left end surface) of the upper step portion 51 and the upper surface 522 of the lower step portion 52 is ≥90°, so as to facilitate processing . the

Fig. 4 shows the axial sectional view of the end cap 5 according to the second embodiment of the present invention, as shown in Fig. The second end surface 53 (the right end surface in FIG. 4 ) of the cover 5 is open, so that the weight of the end cover 5 is reduced, the materials used are reduced, and the cost is saved. the

Fig. 5 shows an axial sectional view of an end cap 5 according to a third embodiment of the present invention, and the embodiment shown in Fig. 6 is a further improvement on the embodiment shown in Fig. 5, wherein the lower step portion 52 of the end cap 5 The first end wall (left end wall) is provided with a through hole 523, so that when the end cover 5 is installed in the header of the heat exchanger 100, the refrigerant distribution pipe 6 in the header can pass through the end cover 5 (refer to Fig. 18). the

Fig. 6 shows an axial sectional view of an end cap 5 according to a fourth embodiment of the present invention, the embodiment shown in Fig. 6 is a further improvement on the embodiment shown in Fig. A boss 524 is formed on the left end wall, and the through hole 523 passes through the boss 524 . Thereby, the strength of the portion where the end cover 5 supports the refrigerant distribution pipe 6 can be increased. the

7-8 show an end cap 5 according to a fifth embodiment of the present invention, wherein FIG. 7 is a perspective view of an end cap 5 according to a fifth embodiment of the present invention, and FIG. 8 is a shaft of an end cap 5 shown in FIG. 7 To the sectional view. As shown in FIGS. 7-8 , a hollow cavity 54 is formed inside the end cap 5 , wherein the upper surface of the lower step portion 52 is a concave arc-shaped surface. the

9-10 show an end cap 5 according to a sixth embodiment of the present invention, wherein Fig. 10 is a schematic perspective view of an end cap 5 according to a sixth embodiment of the present invention. As shown in FIGS. 9-10 , a hollow cavity 54 is formed inside the end cap 5 , wherein the upper surface of the lower step portion 52 is an upwardly convex arc-shaped surface. the

Figures 13 and 14 show an end cap 5 according to a seventh embodiment of the present invention, wherein Fig. 13 is an axial sectional view of an end cap 5 according to a seventh embodiment of the present invention, and Fig. 14 is a view of an end cap 5 shown in Fig. 13 right elevation. As shown in FIGS. 13 and 14 , a flange 55 extending radially outward is formed on the periphery of the second end (right end) of the end cover 5 . the

Figures 15 and 16 show an end cap 5 according to an eighth embodiment of the present invention, wherein Fig. 15 is an axial sectional view of an end cap 5 according to an eighth embodiment of the present invention, and Fig. 16 is a view of an end cap 5 shown in Fig. 15 Viewed from the right side, the end cap 5 according to the eighth embodiment of the present invention is a further improvement on the seventh embodiment, wherein a flap extending toward the first end (left end) is integrally provided on the outer periphery of the flange 55 of the end cap 5 Side 56. According to the end cover 5 of the eighth embodiment of the present invention, since the flange 55 and the flange 56 are provided, the end cover 5 has elasticity in the radial direction, thereby facilitating installation. the

A heat exchanger 100 according to an embodiment of the present invention is described below with reference to FIGS. 17-19 . the

Fig. 17 shows a heat exchanger 100 according to a first embodiment of the invention. As mentioned above, the heat exchanger 100 according to the embodiment of the present invention includes a first header 1, a second header 2, a heat exchange tube 3, the heat exchange tube 3 is, for example, a flat tube, fins 4 and end caps 5 . the

The two ends of the heat exchange tube 3 are respectively inserted into the first header 1 and the second header 2 to connect the first header 1 and the second header 2. 4 fins are respectively arranged on the adjacent heat exchange between tubes 3. The end cap 5 can be any one of the above-mentioned end caps, the end cap 5 is arranged in one end of at least one header for closing the one end, and the upper step portion 51 of the end cap 5 is adjacent to the heat exchange tube 3 and at least The junction of a header and the lower step 52 is remote from said junction. the

FIG. 17 shows only one end cap 5 closing the second end (right end in FIG. 17 ) of the first header 1 . As shown in FIG. 17 , when the end cap 5 is installed into the right end of the first header 1 , the lower step portion 52 of the end cap 5 extends leftward beyond the outermost sidewall adjacent to the right end of the first header 1 . The heat pipe 3 may be flush with the outermost heat exchange pipe 3 . The second end (right end) of the end cover 5 is flush with the right end of the first header 1, in other words, the length L2 of the lower step portion 52 ≥ the distance M between the outermost heat exchange tube 3 and the right end of the first header 1 . Of course, in order to install the end cover 5, the height H of the lower step portion 52 of the end cover 5 should be smaller than the end of the heat exchange tube 3 inserted into the first header 1 and the first header 1 opposite to the end. The distance B between the inner walls. the

As mentioned above, the heat exchanger 100 according to the embodiment of the present invention can reduce the stress on the outermost heat exchange tubes and increase the burst strength of the outermost heat exchange tubes due to the stepped end cover 5, thereby improving the overall The blasting strength of the heat exchanger improves the service life, which has been analyzed in detail above, and will not be described again here. the

Fig. 18 shows a heat exchanger 100 according to the second embodiment of the present invention, wherein the end cover 5 is hollow and the first end wall of the lower step portion 52 is provided with a through hole 523, so the first header 1 A refrigerant distribution pipe 6 can be inserted, and the end cover 5 can also support and fix the refrigerant distribution pipe 6 . the

Fig. 19 shows a heat exchanger 100 according to a third embodiment of the present invention. Compared with the second embodiment shown in Fig. 18, a boss 524 is provided around the through hole 523 in the hollow cavity 54, so that the end cover can be improved. 5 The strength of the part that supports the refrigerant conduit 6. the

Therefore, according to the end cover of the embodiment of the present invention, the burst strength of the heat exchanger with it can be improved, thereby increasing the service life. the

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific embodiments described in conjunction with the embodiments or examples A feature, structure, material, or characteristic is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. the

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents. the

Claims (10)

1. end cap; Be used to seal the header of heat exchanger; It is characterized in that said end cap is limited with first end and second end on its length direction, it is to have the step-like of at least two length on the length direction of said header that said end cap stretches into the inner part of said header; Said end cap stretches into the following rank portion that the inner part of said header comprises the last rank portion with minimum length and has maximum length; First end face of said down rank portion constitutes first end face of said end cap, and said first end face of going up rank portion and following rank portion is towards the inside of said header, and said second end face of going up rank portion and following rank portion deviates from the inside of said header.

2. end cap according to claim 1 is characterized in that, said end cap is by the truncated cone body or have rectangle or the column of square cross section is processed.

3. end cap according to claim 1 is characterized in that said end cap is processed by cylinder.

4. end cap according to claim 3 is characterized in that, the said end cap single-stage that goes up rank portion and following rank portion formation of serving as reasons is step-like.

5. end cap according to claim 3 is characterized in that, the said rank portion of going up is concordant with second end face of said rank portion down and constitute second end face of said end cap, and said end cap is formed with the cavity that opens wide at its second end.

6. end cap according to claim 5 is characterized in that, said first end wall of rank portion down is provided with through hole.

7. end cap according to claim 6 is characterized in that, in said cavity, on first end wall of following rank portion, is formed with boss, and said through hole connects boss.

8. end cap according to claim 3 is characterized in that, the periphery edge of second end of said end cap is formed with the flange that extends radially outward, and the periphery of said flange is along the flange that is provided with integratedly towards first end extension of said end cap.

9. a heat exchanger is characterized in that, comprising:

First header;

Second header;

Heat exchanger tube, the two ends of said heat exchanger tube insert respectively in first and second headers to connect first and second headers;

Fin, said fin are separately positioned between the adjacent heat exchanger tube; With

End cap; Said end cap is according to each described end cap among the claim 1-8; Wherein said end cap is arranged in the end of at least one header and is used to seal a said end, and the contiguous heat exchanger tube of last rank portion of said end cap and the junction of said at least one header and said time rank portion are away from said junction.

10. heat exchanger according to claim 9 is characterized in that, following rank portion the extending axially above the outermost heat exchanger tube adjacent with a said end or concordant with this outermost heat exchanger tube along said at least one header of said end cap.

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