CZ9602008A3 - Heat-exchanging tube for conveying coolant - Google Patents

Abstract

A refrigerant tube (T1) for use in heat exchangers comprises a flat tube (7) having parallel refrigerant passages (6) in its interior and comprising upper (1) and lower (2) walls and a plurality of reinforcing walls (5) connected between the upper and lower walls, the reinforcing walls extending longitudinally of the tube and spaced apart from one another by a predetermined distance. The reinforcing walls are each formed with a plurality of communication holes (8) for causing the parallel refrigerant passages to communicate with one another therethrough. Each of the reinforcing walls is 10 to 40% in opening ratio which is the proportion of all the communication holes in the reinforcing wall to the reinforcing wall. <IMAGE>

Description

(57)

The coolant heat transfer tube (T1) consists of a flat aluminum tube (7) with parallel coolant passages (6) inside it, consisting of an upper wall (1) and a lower wall (2) and comprising reinforcing walls (5) connected to the upper wall (1) and bottom wall (2). The reinforcing walls (5) are arranged in the longitudinal direction of the flat aluminum tube (7) with predetermined distances from each other. The reinforcing walls (5) are provided with connecting openings (8) for interconnecting parallel refrigerant passages (6), each reinforcing wall (5) having a ratio of the sum of the cross-sectional areas of all connecting openings (8) to the total area of the reinforcing wall (5). 10 to 40%.

'Τ’Ί /

01-843-96-Ηθ

PV 2008-96

Heat transfer tube for refrigerant lines * --- Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat transfer tube for conducting refrigerant, in particular a heat exchange tube for heat exchangers, and in particular for condensers and evaporators used in air cooling systems of motor vehicles.

The term aluminum used in the specification and claims includes both pure aluminum and aluminum alloys.

BACKGROUND OF THE INVENTION

JP-B-45300/1991 discloses a condenser used in a motor vehicle air-conditioning system comprising two manifolds arranged on the left and right sides of a condenser spaced apart and parallel to each other, between which parallel flat heat exchangers are arranged coolant conduits connected at their opposite ends to said manifolds and having corrugated fins arranged in passages of air between adjacent heat exchange pipes and brazed to said adjacent heat exchange pipes, with an inlet pipe and a lower end attached to the upper end of the left manifold an outlet pipe is connected to the right manifold, and inside the left manifold a left partition is provided as an intermediate wall located above the central portion of the left manifold, and within the right manifold a right partition is provided wherein the number of heat transfer tubes between the inlet tube and the left baffle and the number of heat exchange tubes between the left baffle and the right baffle, and the number of heat exchange tubes between the right baffle and the outlet tube, decreases from top to bottom. The refrigerant in the vapor phase entering the inlet pipe flows through the condenser zigzag before it exits the outlet pipe, from which it exits in the liquid phase. The capacitors of the described design are referred to as parallel or multiple flow capacitors and achieve high efficiency, low pressure losses and are particularly compact, and are currently very often used in place of conventional serpentine flow capacitors.

It is desirable that the flat refrigerant heat transfer tube used in the condensers be pressure resistant, as the refrigerant is supplied to the heat exchange tube in the form of a high pressure gas. To meet this requirement and to achieve high heat exchange efficiency, the refrigerant heat transfer tubes used are flat aluminum tubes consisting of an upper wall and a lower wall, with a reinforcing wall arranged in the longitudinal direction between the upper and lower walls. .

However, this reinforcing wall arranged in the heat exchange tube creates independent parallel coolant passages within the heat exchange tube. The air flows perpendicular to the parallel heat exchange tubes, so that the heat exchange efficiency is consequently higher in the heat exchange tubes on the air inlet side than in the heat exchange tubes on the air outlet side. That is, the gaseous refrigerant condenses rapidly to liquid in the heat exchange tubes at the inlet side, while the refrigerant remains in the heat exchange tubes at the outlet side. This means that the refrigerant flows unevenly through the heat exchange tubes, so that high heat exchange efficiency cannot be achieved in this embodiment.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a refrigerant heat transfer tube intended for use in heat exchangers by means of which high heat exchange efficiency can be achieved.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a coolant heat transfer tube comprising a flat tube with parallel coolant passages inside, which is formed by an upper wall and a lower wall, and comprises reinforcing walls connected to the upper wall and the lower wall, the reinforcing walls are arranged in the longitudinal direction of the flat tubes at predetermined spacing from each other, and said reinforcing walls are provided with connecting openings for interconnecting parallel refrigerant passages, and wherein each reinforcing wall has a ratio of the sum of the cross-sectional areas of all connecting openings to the total reinforcing surface walls ranging from 10 to 40%.

The refrigerant, which passes through parallel passages in the heat exchange tubes, flows through the connection openings along the width of the heat exchange tube, so that it diffuses into each part of all passages, while the partial refrigerant flows mix with each other. This means that there are no temperature differences in the coolant flowing through the individual passages, so that the coolant condenses both at the inlet side and at the outlet side of the condenser, flowing evenly so that an increased heat exchange efficiency is achieved. Said ratio of the sum of the cross-sectional areas of all connection openings to the total area of the reinforcing wall affects the thermal conductivity. When this ratio is in the range of 10 to 40%, this means that sufficient thermal conductivity is achieved, and the heat exchange efficiency of the coolant conduit is thereby further improved. Said ratio is limited to a range of 10 to 40% because if the ratio is less than 10%, the thermal conductivity will not increase and further because the conductivity will not increase even if the ratio is higher than 40%, since this only increases the coefficient of friction. The value of said ratio ranges from 10 to 40%, preferably from 10 to 30%, and most preferably about 20%.

The connection openings have a cross-sectional size to allow a continuous flow of coolant through the connection openings between adjacent passages, to eliminate the risk of these solder holes becoming clogged by the solder during brazing and to in no way affect the pressure resistance of the heat exchange tube. The spacing of the connection holes is such that these connection holes do not reduce the pressure resistance of the heat exchange tube, while allowing a continuous flow of coolant across the reinforcing walls.

The connecting openings in the reinforcing walls are preferably arranged in a checkered pattern from above.

They are looking

The mutual distance of the reinforcing heat exchange tube is preferably when the distance increases above 4 mm, this will be the heat exchange efficiency.

walls 4 mm. take behind in the width direction if this result reduction

The height of the reinforcing walls is preferably up to 2 mm. At a height of more than 2 mm, there is a difficulty in producing a compact heat exchanger and, on the other hand, an increase in the resistance to air passage, resulting in a deterioration of the heat exchange efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged cross-sectional view of the heat exchanger tube of the first embodiment; FIG. 2 is an enlarged sectional view of the heat exchanger tube ^of FIG. 1; FIG. Fig. 3-3 of Fig. 1, Fig. 4 is a cross-sectional view showing the production of aluminum sheet by rolling intended for the formed heat exchange tubes according to the first embodiment of the invention; Fig. 5 is a cross-sectional view showing cuts in the upper edges of the reinforcing walls of Fig. 4; Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 5; Fig. 7 is a longitudinal cross-sectional view illustrating the formation of reinforcing walls and slits at their upper edges in a single operation; Fig. 8 in enlarged view in perspective and exploded; according to a first embodiment of the invention during its manufacture, FIG. 9 Fig. 10 is a cross-sectional view of a flat coolant tube according to a third embodiment of the invention; Fig. 11 is a cross-sectional view of a coolant tube according to a fourth embodiment of the invention; Fig. 13 is a cross-sectional view of a flat heat transfer tube according to a sixth embodiment of the invention; Fig. 14 is a graph representing the result of the first evaluation test, i.e. the relationship between the average quality X coolant and the thermal conductivity hA; FIG. 15 is a graph representing the result of the second evaluation test, i.e., the relationship between the average X quality of the refrigerant and the thermal conductivity hA; FIG. 16 is a graph representing the result of the third evaluation test, i.e. the relation between the sum ratio cross-sectional areas of all connection openings relative to the total area of the reinforcing wall and thermal conductivity hA at an average X coolant quality of 20%, 50% or 80% and the relationship between said ratio and friction coefficient f when the average X coolant quality is 50%; representing the result of the fourth evaluation test, that is to say, the relationship between the sum of the cross-sectional areas of all connecting openings to the total area of the reinforcing wall and the thermal conductivity hA at an average X coolant quality of 20%, 50% or 80%; Fig. 18 is a graph representing the result of the fifth evaluation test, i.e., the relationship between the pressure losses ^{and the} amount of heat emitted by the front face of the unit, i.e. Q / Fa, for condensers formed from heat exchange tubes according to the invention; 19 is a front view of a capacitor formed from flat plates h of heat exchange tubes according to the invention.

EXAMPLES OF THE INVENTION

Fig. 19 shows a condenser formed from flat heat exchange tubes according to the invention. The condenser consists of two collector tubes 61, 62, arranged on the left and right sides of the capacitor parallel and spaced apart from each other, the opposing ends of which are connected flat parallel heat exchange tubes 63 with opposing ends, wherein in the air passages between Corrugated ribs 64 are disposed adjacent the heat transfer tubes 63 and brazed to the heat exchange tubes 63. The inlet tube 65 is connected to the upper end of the left manifold 61 and the lower end of the right manifold 62 is connected to the outlet manifold 66. Inside the left manifold 61 there is a left partition 67 located above the central portion thereof and inside the right manifold. 62, a right baffle 68 is provided that is located below the central portion thereof. The number of heat transfer tubes 63 between the inlet tube 65 and the left baffle 67, the number of heat transfer tubes 63 between the left baffle 67 and the right baffle 68, and the number of heat transfer tubes 63 between the right baffle 68 and the outlet tube 66 decrease respectively. The refrigerant entering the inlet pipe in the vapor phase flows zigzagging through the condenser until it finally exits the outlet pipe 66 in the liquid phase.

The heat transfer tubes 63 for use in this capacitor are designed as heat transfer tubes according to the invention. These heat exchanger tubes according to the invention will now be described. All following embodiments. they have a ratio of the sum of the cross-sectional areas of all connecting openings to the total area of the reinforcing wall in the range of 10 to 40%. The connecting holes provided in the reinforcing walls have a checkerboard arrangement seen from above.

First embodiment

This first embodiment is shown in FIGS. 1 to 3. The heat exchanger tube T1 for heat exchangers consists of a flat aluminum tube 7 having parallel cooling passages 6 inside each other and consisting of an upper wall 1 and a lower wall 2 which are flat and from the left vertical side wall 3 and the right vertical side wall 4, which are connected to the left side edges of the top wall 1 and the bottom wall 2 and to the right side edges of the top wall 1 and the bottom wall 2, the reinforcing walls 5, which extend through the flat aluminum tube 7 along its length and arranged at a predetermined distance from each other, are connected. The reinforcing walls 5 are provided with rectangular connecting openings 8 which allow the refrigerant passages 6 to be connected to one another in parallel.

The flat aluminum tube 7 is formed from the upper aluminum sheet 9 and the lower aluminum sheet 10 by bending opposite side edges of the lower aluminum sheet 10 and attaching these bent side edges to respective side edges of the upper aluminum sheet 9 to form a cavity between the two aluminum sheets 9, 10.

The stiffening walls 5 are formed by mutually parallel elongated protrusions 11 extending inwardly from the bottom wall 2 and connected to the inner surface of the upper wall 1. The rectangular connecting holes 8 are formed by rectangular slots 12 at the upper edge of each elongate protrusion spaced from predetermined intervals. with their open sides located at the top wall 1.

The heat transfer tube T1 is produced as follows.

As shown in Fig. 4, a sheet of aluminum sheet in the form of a sheet having a braze layer on its underside having a thickness greater than the thickness of the top wall and the bottom wall of the heat exchange tube to be produced is first rolled between a pair of rollers 13 17, i.e. between the upper roller 13 and the lower roller 17. The upper roller 13 is provided with mutually parallel annular grooves 14 / arranged at predetermined distances, as well as first small-diameter portions 15 formed on the outer sides of the annular groove arrangement 14, the diameter of the first portions 15 is equal to the diameter of the annular grooves 14, and the second small-diameter portions 16 located outside the respective first small-diameter portions 15, the diameter of the second portions 16 being smaller than the diameter of the first portions 15. at its outer ends the large diameter portions 18 whose faces are flush with the faces of the other small diameter portions 16 on the upper cylinder 13, the width of the second small diameter portions 16 being greater than the width of the large diameter portions 18. The circumferential surfaces of the rollers 13, 17 form a flat part 19 forming the bottom wall 2 by thinning the sheet blank to the required thickness. The rollers 13, 17 also form elongated protrusions 11 projecting from the flat part

19. in a shape corresponding to the annular grooves 14, upright parts are formed at respective side edges of the flat part 19

20. each of which is provided with an inner shoulder 20a, the height of which corresponds to the height of the elongate protrusions 11, and from whose outer edge a thin wall 20b extends. Thus, a rolled aluminum sheet 21 is formed by rolling.

As shown in FIGS. 5 and 6, the rolled aluminum sheet 21 then passes between the pair of rollers 22. 24. i.e., the upper roller 22 and the lower roller 24. The upper roller 22 is provided with rectangular projections 23 arranged at a predetermined distance from the 3, which correspond to mutually parallel annular grooves 14 on the upper cylinder 13 in a previous operation. By rolling between the rollers 22, 24, rectangular slots 12 are formed at predetermined intervals at the upper edges of the elongate protrusions 11, thereby forming a lower aluminum sheet 10.

The projections 23 on the upper roller 22 are arranged in a checkerboard pattern, so that even the rectangular slots 12 formed at the upper edges of mutually parallel elongate projections 11 have a checkerboard arrangement when viewed from above.

The above method of manufacturing the lower aluminum sheet 10 requires two operations to form elongated protrusions 11 with rectangular slots 12. However, as shown in FIG. 7, elongated protrusions 11 with rectangular slots 12 may be formed in a single operation when the lower cylinder is combined with one another. 17 of the first operation with the upper cylinder 26, which is provided with mutually parallel annular grooves 14 with protrusions 25 arranged at predetermined intervals apart, whose height is less than the depth of the annular grooves 14.

Furthermore, it is necessary to produce an upper aluminum sheet 9 which is formed of a sheet whose opposite sides are provided with a solder layer. As shown in FIG. 8, it has an upper aluminum sheet 9.

bevels 27 are bevelled downwardly at their opposed side edges. As shown in FIG. 2, each side edge of the top aluminum sheet 9 is supported on the inner shoulder 20a of the upright portion 20 of the bottom aluminum sheet 10, and the thin wall 20b, indicated in dashed lines in FIG. Then, the lower side of the upper aluminum sheet 9 is brazed to the inner shoulder 20a of the upright portions 20 of the lower aluminum sheet 10 and to the upper ends of its elongated projections 11, thereby forming a heat transfer tube T1.

The peripheral surface of the upper cylinder 13 may be provided with depressions and protrusions, the cross section of which is triangular in the form of a wave or knurl. The lower aluminum sheet 10 is then provided with protrusions and depressions extending in its longitudinal direction over its entire inner side, or its inner side is provided with protrusions or depressions in the form of a lattice. This increases the area of the bottom wall 2. ·

Second embodiment

The second embodiment is shown in Fig. 9. The heat exchange tube T2 is intended for heat exchangers. The heat exchange tube T2 has the same construction as in the first embodiment, except that the heat exchange tube T2 has a left side wall 28 and a right side wall 29, inverted trapezoid connection holes 30 and relatively low upward projections 31 that are integrally formed with the bottom wall 2 extending therefrom in its longitudinal direction and spaced apart from each other, thereby providing an increased heat transfer surface. The connecting holes 30 may be formed by trapezoidal cut-outs 32 in the upper edges of the elongate protrusions 11.

The heat exchange tube T2 is formed by a flat aluminum tube 33 which is formed by bending the opposite side edges of the upper aluminum sheet 34 and the lower aluminum sheet

35. by fitting the bent side edges of the lower aluminum sheet 35 to the bent side edges of the upper aluminum sheet and joining the interposed parts to form a cavity between the aluminum sheets 34, 35.

More specifically, the side walls 28, 29 are formed as follows. On the opposite edges of the lower aluminum sheet 35, upright portions 36 are formed having the same height as the stiffening walls 5, and at the lower edge of each upright portion 36 a bevel 38 is formed which extends obliquely upwards. As indicated in dotted lines in FIG. 9, vertical portions 37 are formed on opposite side edges of the top aluminum sheet 34, these vertical portions 37 abutting the outer side sides of the upright portions 36 and extending down slightly below the lower side of the bottom wall 2. Projections 37a. by which the vertical portions 37 extend beyond the underside of the bottom wall 2, they fold over the bevels 38 formed on the lower aluminum sheet 35, whereupon the portions of the aluminum sheets 34, 35 which touch each other are brazed together.

Third embodiment

The third embodiment is shown in Fig. 10. The heat transfer tube T3 is for heat exchangers and consists of a flat aluminum tube 22. The flat aluminum tube 39 is made of aluminum sheet 40 in the form of a sheet with a solder layer on one side. a hairpin-like central portion with a solder layer therein forming a cavity, the opposing side edges bending in an arch shape and the side edges abutting each other. The flat aluminum tube 39 thus formed has therefore a left side wall 41 and a right side wall 42 in the form of an arc. The butt joint 43 so formed is oblique in cross-section, so that its area is larger.

Each reinforcing wall 44 is formed by joining the elongate projection 44a. extending downwardly from the top wall 1, with an elongate projection 44b extending upwardly from the bottom wall 2. Each connection aperture 45 is formed from two trapezoidal cutouts 45a, 45b. These trapezoidal cutouts 45a. 45b are formed at predetermined intervals at the upper edges of the protrusions 44a extending downwards and the upper edges of the protrusions 44b extending upwards.

Fourth embodiment

A fourth embodiment is shown in Fig. 11. The heat transfer tube T4 is provided here with two kinds of reinforcing walls 46. The reinforcing walls 46 of one type are formed by elongated protrusions 46a extending downwardly from the top wall i and connected to a flat portion of the inner side of the bottom wall 2. the walls 46 of another kind are formed by elongated protrusions 46b extending upwardly from the bottom wall 2 and connected to a straight portion of the inner side of the top wall 1. The trapezoidal connection holes 47 are formed by trapezoidal cutouts 47a, 47b formed at the lower edge of the elongated protrusions 46a the open sides are closed by the top wall 1 or the bottom wall 2. Except for this feature, the fourth embodiment is identical to the third embodiment.

Fifth embodiment

A fifth embodiment is shown in FIG. 12. The heat exchange tube T5 is intended for heat exchangers. The heat transfer tube T5 has stiffening walls 48 which are formed by elongated protrusions 48a extending downwardly from the top wall 1 and connected to the flat inner side of the bottom wall 2. The trapezoidal connection apertures 49 are formed by forming trapezoidal cutouts 49a at predetermined intervals at the lower edges of the elongated walls. the projections 48a facing downwards, the trapezoidal cutouts 49a being closed on the open side by the bottom wall 2. A fifth embodiment is the same as the third embodiment except for this feature.

Sixth version

The sixth embodiment is shown in FIG. 13. The heat exchange tube T6 is intended for heat exchangers. The heat transfer tube T6 is formed by a flat aluminum tube 50. The flat aluminum tube 50 is formed from the upper aluminum sheet 51 and the lower aluminum sheet 52 by bending the opposing side edges of these aluminum sheets 51, 52 into an arc to each other to form a cavity therebetween. and the aluminum sheets 51, 52 abut with their lateral edges. Except for this feature, the sixth embodiment is identical to the third embodiment. The butt joint 53 and the butt joint 54 are oblique in cross-section, as in the third embodiment.

The aluminum sheet having the edges and other features described above and used in the above-described embodiments may be replaced by an extruded aluminum article with a specific cross-sectional shape.

A comparison of the exemplary embodiments of the invention will now be made with reference samples. The heat transfer tubes according to the exemplary embodiments of the invention and the comparative samples have the cross-sectional shape shown in FIG. 1.

Example 1

The heat exchange tube has a length of 508 mm, a distance of 16.5 mm between the vertical side walls 3, 4, a height of 1 mm between the upper wall 1 and the lower wall 2, six reinforcing walls 5 with a pitch

2.4 mm and 1.6 mm thick, P pitch 1.6 mm connecting holes 8, length L 0.8 mm connecting holes 8, height H 0.2 mm connecting holes 8, the ratio of the sum of the cross-sectional areas of the connecting holes 8 to the area of the reinforcing wall 5 is 10%.

Example 2

The same heat exchange tube as in Example 1, except that the heat exchange tube has a height H of 0.4 mm of the connecting holes 8 and the ratio of the sum of the cross-sectional areas of the connecting holes 8 to the area of the reinforcing wall 5 is 20%.

Example 3

The same heat exchange tube as in Example 1 except that the heat exchange tube has a height H of 0.6 mm of the connecting holes 8 and the ratio of the sum of the cross-sectional areas of the connecting holes 8 to the area of the reinforcing wall 5 is 30%.

Example 4

The same heat exchange tube as in Example 1 except that the heat exchange tube has a height H of 0.8 mm of the connecting holes 8 and the ratio of the sum of the cross-sectional areas of the connecting holes 8 to the area of the reinforcing wall 5 is 40%.

Comparative example

The same heat exchange tube as in Example 1, except that the heat exchange tube is provided with no connection holes in the reinforcing walls.

Evaluation test

The heat exchange tubes of Example 1 and the comparative sample were used to determine the relationship between the average X coolant quality (fraction of the vapor mass in the coolant) and the thermal conductivity hA (h: heat transfer coefficient, A: heat transfer area within the heat exchange tube). The method of determining this dependence was as follows. The heat exchange tube was placed in the cooling water channel, with HFC134a refrigerant was passed through the heat exchange tube, and cooling water was passed through the channel. At the end of the specific time, the flow rate G of the refrigerant was set at 400 kg / m ² .s, the coolant inlet temperature was 65 Ca and the heat flux between the cooling and cooling water was 8 kW / m ² . The cooling water flow was set to give a Reynolds number of 1500. The thermal conductivity hA was measured at various values of average quality X coolant.

The result is shown in Fig. 14, which implies that when the reinforcing walls are provided with connection holes, the thermal conductivity hA is greater at any value of average quality X coolant than when the connection holes are not provided.

Evaluation test

The heat exchange tubes of Example 2 and the comparative sample were used to determine the relationship between the average refrigerant quality X and the heat transfer coefficient h in the same manner as in Evaluation Test 1. The results are shown in Figure 15.

Figure 15 shows that at any value of average coolant quality X, the heat transfer coefficient h is greater when the reinforcing walls are provided with connection holes than when the connection holes are not provided.

Evaluation test

The heat exchange tubes of Examples 1-4 and the comparative sample were used to determine the relationship between the sum of the cross-sectional areas of all connecting holes to the total reinforcing wall area and the thermal conductivity hA at an average X coolant of 20%, 50% or 80%. between the ratio of the sum of the cross-sectional areas of all connecting holes to the total area of the reinforcing wall and the coefficient of friction when the average X coolant quality was 50% (Reynolds coolant number: 10 ₄ ). FIG.

Fig. 16 shows that at any value of average coolant quality X, the thermal conductivity hA is greater when the reinforcing walls are provided with connecting holes than when the connecting holes are not treated, and that the thermal conductivity hA is greatest when the ratio of the sum of the cross-sectional areas of all connecting holes to the total area of the reinforcing wall is 20%.

Evaluation test 4

The heat exchange tubes of Examples 1-4 and the comparative sample were used to determine the relationship between the sum of the cross-sectional areas of all connecting holes to the total area of the reinforcement wall and the heat transfer coefficient h at an average X coolant quality of 20%, 50% or 80%. the relation between the sum of the cross-sectional areas of all joint openings to the total area of the reinforcing wall and the coefficient of friction when the average quality X coolant was 50% (Reynolds coolant number: 10 ₄ ). shown in FIG. 17.

It can be seen from FIG. 17 that, at any value, it is average

For the X coolant quality, the heat transfer coefficient h is greater when the reinforcing walls are provided with connecting openings than when the connecting openings are not provided and that the heat transfer coefficient h is greatest especially when the ratio of the sum of the cross-sectional areas of all the area of the reinforcing wall is 20%.

Evaluation test 5

Three types of multiple flow capacitors, as shown in Fig. 19, were produced using the heat exchange tube of Example 2 or the comparative sample. More precisely, 37 heat exchanger tubes with corrugated ribs were used, the width of which was 22 mm, the height of 7 mm and the spacing of 1 mm. A base portion of 326 mm width, 330.5 mm height and a front side size of 0.108 m ² was formed, with the opposite ends of each heat exchange tube being connected to the collector tubes, i.e., the left condenser of the opposite condenser collector tube and the right collector tube. In Type I (single pass) no baffles were provided in the manifolds. For Type II, the left bulkhead inside the left manifold was placed above the middle portion, the right bulkhead in the right manifold was placed below the middle portion, 20 heat transfer tubes were placed above the left bulkhead in the left manifold, 11 heat transfer tubes were arranged between the two bulkheads and 6 heat exchange tubes were placed under the right bulkhead in the right collection tube (three passages). The Type III capacitor had two left bulkheads located at the top and bottom of the left manifold, two right bulkheads located inside the right manifold, one right bulkhead at the level between the two left bulkheads at the left manifold and the other right bulkhead at the level below the bottom. left bulkhead in the left manifold, with 12 heat transfer tubes positioned above the upper left bulkhead in the left manifold, 9 heat transfer tubes arranged between the upper left bulkhead of the left manifold and the upper right bulkhead of the right manifold, 7 heat transfer pipes positioned between the upper right right header tube and bottom left header tube, 5 heat transfer tubes were placed between the lower left partition in the left header tube and the lower right partition in the right header tube, and 4 heat exchange tubes were located below the lower right partition in the right collecting tube (5 passes). The capacitors were tested for the relationship between the pressure drop of the ap and the amount of heat radiated per unit of face, i.e. Q / Fa. The results are shown in Figure 18.

As shown in FIG. Of the tube, with holes to be improved, the condenser containing heat exchangers having reinforcing walls having a joint ratio of the cross-sectional area of all the connecting total surface area of the reinforcing wall of 20% represents an embodiment over the reinforcing walls are provided with connecting openings and achieve an improvement even if the pressure losses are the same.

Claims (13)

PATENTOV -O 2 σ »? c o S d κ CLAIMS 1. A heat transfer tube for conducting refrigerant, characterized in that it comprises a flat tube with parallel refrigerant passages inside which is formed by an upper wall and a lower wall and comprises reinforcing walls connected to the upper wall and the lower wall, said reinforcing walls being arranged. in the longitudinal direction of the flat tube at predetermined spacings from each other, wherein the reinforcing walls are provided with connecting openings for interconnecting parallel refrigerant passages, and wherein each reinforcing wall has a ratio of the sum of the cross-sectional areas of all connecting openings to the total area of the reinforcing wall 10 to 40%. Heat transfer tube according to claim 1, characterized in that the ratio of the sum of the cross-sectional areas of all the connecting holes to the total area of the reinforcing wall is 10 to 30%. The heat exchange tube of claim 1, wherein the ratio of the sum of the cross-sectional areas of all the connecting holes to the total area of the reinforcing wall is about 20%. 4. The heat exchange tube of claim 1, 2 or 3, wherein the connection holes are rectangular or trapezoidal in shape. 5. The heat exchange tube according to claim 1, 2 or 3, wherein the connection openings formed in the reinforcing walls have a checkerboard arrangement seen from above. 6. A heat transfer marking tube for conduction by being coolant comprising a surface i an aluminum tube with parallel refrigerant passages therein comprising a top wall and a bottom wall and comprising reinforcing walls, the reinforcing walls being arranged in the longitudinal direction of the flat aluminum tube at predetermined spacing from each other, and wherein the flat aluminum tube is made of aluminum and wherein the reinforcing walls are provided with an elongated protrusion extending from the aluminum sheet and integral therewith, and further provided with connection openings for interconnecting parallel refrigerant passages, and wherein each reinforcing wall has a ratio of the sum of the cross-sectional areas of all connecting openings to the total area. the reinforcing walls in the range of 10 to 40%, and wherein the connecting holes in the reinforcing walls are arranged in a checkered pattern from above. Heat transfer tube according to claim 6, characterized in that the aluminum sheet consists of a sheet provided with a metal solder layer on at least one of its opposite sides. Heat transfer tube according to claim 6, characterized in that the flat aluminum tube is formed by bending the opposite side edges of at least one of the two aluminum sheets, i.e. the top and bottom aluminum sheets, and joining the bent side edges with respective side edges of the other aluminum sheet. to form a cavity between the two aluminum sheets. The heat exchange tube of claim 6, wherein the flat aluminum tube is formed by bending opposite side edges of the top aluminum sheet and the bottom aluminum sheet, fitting the bent side edges of one aluminum sheet to the bent side edges of the other aluminum sheet, and attaching the assembled parts for the sheet. forming a cavity between the two aluminum sheets. 10. The heat exchange tube of claim 6, wherein the flat aluminum tube is formed from an aluminum sheet by folding the aluminum sheet in the middle along its width to form a cavity, bending at least one of the opposing side edges of the aluminum sheet. the other side edge and the side edges are joined together. 11. The heat exchange tube of claim 2, wherein each reinforcing wall is formed with an elongate protrusion extending downwardly inwardly from the top wall and formed with it in one piece, and with an elongate protrusion extending upwardly inwardly from the top wall. and the joining apertures are formed by combining opposed pairs of slits formed in the lower edge of the elongate protrusion projecting down and at the upper edge of the elongate protuberance projecting up and spaced at predetermined intervals. 12. The heat exchange tube of claim 6, wherein the reinforcing walls are formed by reinforcing walls formed with elongated protrusions extending downwardly from the top wall and formed therewith in one piece and connected to the flat inner side of the bottom wall, and reinforcing walls formed with elongated protrusions extending upwardly from the bottom wall and made with it in one piece and connected to the flat inner side of the upper wall, the two types of reinforcing walls being arranged alternately, and the connecting apertures consist of cutouts formed at the lower edges of the elongated protrusions extending downward and in the upper the edges of the elongate protrusions projecting upwardly and arranged at predetermined intervals, their open sides being closed either by the top wall or the bottom wall. 13. The heat exchange tube of claim 6, wherein each reinforcing wall is provided with an elongate protrusion extending inwardly from the top wall or bottom wall and integrally formed thereto, connected to the flat inner side of the opposite wall, the connection openings being formed by cut-outs formed at the edge of the elongate projection at predetermined intervals, the free sides of which are closed by an upper or lower wall.