KR100237866B1 - Multi pass type evaporator - Google Patents

Abstract

A plurality of tubes 40 each having a long and parallel upper and lower header 14, 30 and pins 44 disposed between the headers 14, 30 and between adjacent tubes 40. The performance of the evaporator formed by the heat exchange module or unit of the lower header (1) at one end portion (34) corresponding to the upper manifold (20) and one end portion (19) in fluid communication with the upper header (14) at one end (19) By using the lower manifold 36 in fluid communication with 30).

Description

Multipass Evaporator

1 is a front view of an evaporator according to the present invention.

2 is a plan view of the evaporator.

3 is an enlarged perspective view of a part of the evaporator.

4 is a partial view of the evaporator tube and internal fins.

5 is a partial schematic view of a one pass evaporator illustrating a temperature profile.

FIG. 6 is a partial schematic view of FIG. 5 of a multipass evaporator, in particular a three pass evaporator.

7 is a front view as in FIG. 1 of a modified embodiment of the present invention.

8 is a plan view of the embodiment of FIG.

9 is a side view of the embodiment of FIGS. 7 and 8;

* Explanation of symbols for main parts of the drawings

10: upper header 12: lower header

14: header tube 20: upper manifold

22, 22 ': baffle 30: header tube

36: lower manifold 40: tube

60,62: upper and lower manifolds 100,102: upper and lower header tubes

The present invention relates to a heat exchanger and in particular to a heat exchanger used as an evaporator.

As is well known, commonly used air conditioning systems which operate in a vapor compression cycle use an evaporator as a cooling means for the conditioned air, and the refrigerant flows through the evaporator and expands in the evaporator. At this time, the refrigerant absorbs the heat of vaporization, and thus typically cools the medium in contact with the heat exchanger tube. The conditioned air flows through the heat exchanger tube described above where fins are typically installed to improve air side heat transfer. The air is cooled at least locally below its dew point to condense water in the air on fins and tubes. This condensate must be removed, and if not removed, it freezes and blocks the air passage.

Various proposals for removing condensate have been disclosed, the simplest of which uses gravity as a possible aid from the air velocity moving through the evaporator. Such a system works better but becomes larger than necessary.

Also, if there is a relatively high speed airflow in a vehicular air conditioning system that operates at high speed so that the fan achieves maximum cooling over a short period of time, it is possible to allow water from the evaporator to prevent moisture from entering the airflow and entering the vehicle's riding space. The moisture must be removed as soon as possible.

One evaporator structure that is ideally suited for use in situations involving the above point of view is Gregorian, dated May 16, 1989. US Patent No. 4,829,780 to Gregory G. Hughes et al., The details of which are incorporated herein by reference.

As will be appreciated by those skilled in the art, evaporators by Hughes et al. Provide excellent, low cost, lightweight collection of condensate in the evaporator, but despite the above, it is possible to improve the usefulness of such evaporators. In order to fine tune such a structure, the present invention achieves such an object.

The main object of the present invention is to provide a novel improved heat exchanger, and in particular the object of the present invention is to provide a novel improved heat exchanger which is ideally suitable for use as an evaporator. It is also a main object of the present invention to provide an evaporator of the type disclosed in the patent of Hughes et al. Described above and having improved operating efficacy.

According to one aspect of the invention, each of the long and parallel upper and lower headers and a plurality of heat exchange modules consisting of a plurality of tubes installed adjacent to each other between the header, the tube is in the transverse direction of the header than the header Small in size, the module is aligned with each other with the corresponding tubes in the module, stacked, assembled, pins installed between adjacent tubes in each module, and an upper manifold in fluid communication with the upper header at one end; And a lower manifold in fluid communication with the lower header at one end corresponding to the one end. This configuration causes the manifold to be present on the same side of the core of the evaporator, thereby improving the performance of the heat exchanger as the evaporator.

According to another feature of the invention, such an evaporator consists of at least two, preferably three, heat exchange units of the above type, wherein the upper and lower manifolds are in fluid communication with the upper and lower headers, respectively, At least one baffle is provided on at least one side, preferably on both sides, such that fluid flowing through the evaporator is arranged to continuously flow through the unit in at least two passes, preferably three passes.

The use of an evaporator constructed by this feature of the present invention results in a more uniform outlet air side temperature that exhibits a uniform core surface temperature without loss of performance over one pass system. As the temperature becomes more uniform, the position of the temperature sensing tube or the like of the thermostat in the core becomes relatively insignificant and can prevent the tendency of condensate to freeze in the vicinity of the lower header.

According to another feature of the invention, the heat exchange unit is generally assembleable from any core, as mentioned above, and the baffle is provided such that fluid flowing through the evaporator flows continuously through each module or heat exchange unit in at least two passes. It is located in at least some headers.

According to another feature of the invention, a relatively narrow core having a core depth of about 2 inches or less is employed, and this feature of the invention employs a meandering pin having a pin density of at least 18 pins per inch. do.

Other objects and this point of the present invention will become apparent from the following detailed description according to the accompanying drawings.

One embodiment of the evaporator according to the invention is shown in the drawings, which is described in particular herein as an evaporator, but in some cases may be used other than the evaporator if necessary, and the invention is intended to include such other uses.

As shown in FIG. 1, the evaporator consists of an upper header, indicated by (10) and a lower header, denoted by (12), and as shown in FIG. 2, the upper header (10) is at least three adjacently located. It consists of a plurality of long tubes 14. The tube 14 is sealed by a plug 18 (FIG. 1) at the right end 16, and at its opposite end 19 the tube 14 is in fluid communication with the interior of the upper manifold 20. have. A plug or baffle 22 is present in the upper manifold 20 so that one header tube 14 is in fluid communication with one end 24 of the upper manifold 20. It is in fluid communication with the opposite end 26. In the illustrated embodiment, one end 24 of the upper manifold 20 may be an outlet for the evaporator.

The lower header 12 consists of the same number of elongated header tubes 30 which are soldered together and sealed together as in 31 while being in contact with each other as clearly shown in FIG. Be sure to

Although not shown, the right end 32 of the tube 30 is sealed by a plug, as indicated by the reference 18, and the left end 34 of the tube 30 is connected to the lower manifold 36. In fluid communication. Thus, the upper and lower manifolds 20 and 36 appear to be on the same side of the evaporator. Connectors 38, such as conventional reducers, may be used for fluid communication between the tubes 14, 30 and each manifold 20, 36.

As fully pointed out in the patent by Hughes et al. Described above, the tube 30 (optionally also the tube 14 is possible) has a rectangular cross section and is preferably circular. The circular shapes of the tubes 14, 30 forming the upper and lower manifolds 20, 36, as well as the upper and lower headers 10, 12 can withstand the evaporator while using minimal material to make these components. Maximize the burst pressure.

As shown in FIG. 1, the upper and lower headers 10, 12 are parallel at regular intervals, and parallel flat tubes 40 are provided in a plurality of parallel rows. The number of rows of the tube 40 is equal to the number of the tubes 14 or the number of the tubes 30, and is three in the example shown. The flat tube is in fluid communication with the interior of the corresponding tube in the header tubes 14, 30, so that fluid communication between the headers 10, 12 is achieved. Therefore, the refrigerant and the like introduced in the illustrated embodiment flow into the lower manifold 36 as indicated by the dotted line in FIG. According to the present invention, a baffle or plug 22 'similar to the baffle or plug 22 is also installed in the lower manifold 36 as shown in FIG. 6, which is indicated by the arrow 39 in FIG. Tube 40 coupled with the second tube of header tube 14 while the refrigerant flows imaginatively through tube 40 coupled with the first tube of header tube 14. Flows downward through the tube 40 coupled with the final tube of the header tube 40 and flows out of the device through the end 24 of the manifold 20, thus being shown The example shows a three pass evaporator. Any air flow through the evaporator is directed in the direction of arrow 41 as shown in FIG. 2, with the result that the refrigerant flows from the rear to the front through the evaporator core, while the air is in a substantially “backflow” form. It flows from the front to the back through the core to the extent that it can be called flow.

The size of the tube 40 disposed between the tubes 14, 30 is slightly smaller than the size of the tubes 14, 30 so that it can be assembled, and the tube 40 has a long slot (not shown) in the tubes 14, 30. Not inserted).

In the illustrated embodiment, there are three approximately identical rows of tubes as described above, and there is a space 42 at the moment of each tube 40, which is relatively small and usually less than 1/4 inch. It becomes

As shown in FIG. 3, the corresponding tube 40 and each row of the tubes 40 are parallel to each other, ie aligned in a common straight line. Thus, as described below, the evaporator is made of a plurality of substantially identical modules or units each consisting of an upper header tube 14 and a lower header tube 30 and a plurality of flat tubes 40, the modules being soldered ( 31) as well as interconnected by manifolds 20 and 36. A meandering pin 44 is installed between adjacent flat tubes 40 in each module, and as shown in FIG. 3, the meandering pin 44 is also common to each module, but the rest described above. As pointed out in the patent by Sus et al., The pins 44 may be provided between modules if necessary.

As is well known, the bent portion of the meandering pin is preferably soldered or glued to the flat surface 46 of the tube 40 and, if necessary, the louver schematically shown as 48 to the meandering pin 44. Can be excreted. 4 shows the density of the pins by the symbol "FPI", which indicates pins per inch. 4, the pin density of 11 pins per inch is shown.

If the depth of the core (measured as shown in Figure 3) is relatively narrow, i.e. approximately 2 inches or less, the evaporator has a conventional pin density ranging from 14 pins per inch to at least 18 to 24 pins per inch. As it increases, performance improves.

Such high pin densities are typically excluded from the evaporator as smaller spaces between the fins are clogged by condensate, which tends to impede or delay the airflow, thus reducing the performance of the evaporator.

5 shows a generally similar evaporator with an upper manifold 60 corresponding to the manifold 20 and a lower manifold 62 corresponding to the manifold 36. Also shown are three rows of tubes 40, wherein the headers 10, 12 coupled thereto are not visible by the upper and lower manifolds 60,62.

The evaporator shown in FIG. 5 does not use any of the baffles 22, 22 'so that a one pass evaporator is formed.

Air passing into the evaporator in the direction of arrow 64 at a temperature of 77 ° F. exits the evaporator at a temperature that varies over a range according to the top to bottom position of the air relative to the evaporator core, and the air near the top of the core Approximately 50 ° F., and the air adjacent to the bottom of the evaporator is approximately 32 ° F.

The latter condition is undesirable because the condensate tends to drain down the tube 40 in the space 42 and collect at the junction of the lower header tube 30, as fully described in the above-described patents of Hughes et al. . As the condensate freezes at a temperature close to the freezing point of the water present at the condensate collection point, it is immediately seen that the core is very likely to freeze.

In contrast, when the baffles 22, 22 'are positioned with the evaporator according to the invention as shown in FIG. 6 in three or more passes, indicated by the arrow 66 in the direction of the arrow 66; Air moving to temperature exits at approximately 42 ° F. at the top of the evaporator and at approximately 40 ° F. at the bottom of the evaporator. Thus, the air temperature becomes more uniform in the embodiment according to the present invention for all purposes and purposes, and the evaporator of the present invention has the same heat transfer performance for the evaporator as shown in FIG.

This fairly uniform air temperature minimizes the possibility of freezing of the condensate and prevents freezing of the core, and as is well known in the art, thermostats or tubes of thermostats are often associated with the evaporator core for a variety of reasons. Combined. Due to the uniformity of air temperature, the placement of such a temperature sensor on the core is not as important as in conventional devices that cannot have such air temperature uniformity.

Further, as shown in FIG. 6 and described above, the lower manifold 36 as the refrigerant inlet and the upper manifold 20 as the refrigerant outlet are used and located on the same side of the core as shown in FIG. Having the lower manifold 36 and the upper manifold 20 improves the performance for the manifold and / or other possible locations of the inlet and outlet.

Another embodiment of the present invention is shown in Figures 7 to 9, in this embodiment the upper header tube 100 and the lower header tube 102 and the upper and lower header tubes 100, respectively as described above. A plurality of modules consisting of a plurality of flat tubes 104 installed in parallel between the 102 is disposed, the flat tube 104 is smaller than the transverse size of the upper and lower header tubes (100, 102) And meandering pin 106 is installed between the tubes in accordance with the patented technology, such as Hughes described above.

In this particular embodiment, tubular manifolds 108 and 110 are used, connected to opposite ends of the header tube 102, and the manifolds 108 are inlet as indicated by arrows 112 and 114 in the figures, respectively. Acts as a manifold, manifold 110 acts as an outlet manifold, and airflow flows in the direction of arrow 116.

According to this embodiment of the present invention, the baffle 120 is located between the ends of the header tube 102, and in the illustrated embodiment only one baffle 120 is installed in each tube 102, but additionally It is also possible to use a furnace baffle, in which case the baffle may be located in the header tube 100. In the illustrated embodiment, two-pass fluid flow occurs in the evaporator, and fluid flows into the manifold 108 and flows to the left side of the header tube 102. From this, the fluid flows to the left side of the header tube 100 in the direction of the arrow 122, and then flows to the right side of the header tube 100 in the direction of the arrow 124. When the fluid reaches the right side of the tube 100, the fluid flows to the right side of the tube 102 in the direction of the arrow 126 and flows out of the manifold 110 in the direction of the arrow 128.

Although not shown, according to the present invention, the baffle may be located in both manifolds and header tubes on both sides from the front to the rear, the rear to the front, and the combination of the multipath flows as necessary.

Claims (11)

A plurality of heat exchange modules, each heat exchange module consisting of a long and parallel upper and lower header, and a plurality of tubes mounted along their lengths between the headers and extending side by side; Fins installed between adjacent tubes in each module; And an upper manifold in fluid communication with the upper header at one end and a lower manifold in fluid communication with the lower header at an end corresponding to the one end, wherein the tube has a size smaller than the header in the transverse direction of the header. And the modules are stacked, assembled and aligned with each other with corresponding tubes therein. 2. The evaporator of claim 1 wherein said lower header is comprised by a header tube and sealingly welded between adjacent header tubes along its length. The evaporator of claim 2, wherein the header tube has a circular cross section. The method of claim 1, wherein the module is provided with at least two, and at least one baffle is provided in one of the manifolds so that the fluid flowing in the evaporator is arranged to continuously flow through the module in at least two passes. Evaporator made. The method of claim 1, wherein at least three modules are provided, and at least one baffle is provided at one of the manifolds such that the fluid flowing in the evaporator is disposed to continuously flow through the module in at least three passes. Evaporator made. The evaporator of claim 1 wherein the modules are assembled to form a core having a core depth of about 2 inches or less, wherein the fins are meandering fins and at least about 18 fins per inch are installed in the tube. . At least two plurality of heat exchange units, each heat exchange unit consisting of an elongated upper and lower header and a plurality of tubes mounted along their lengths between the headers and extending side by side therefrom; Pins extending between adjacent tubes of each unit; Upper and lower manifolds in fluid communication with the upper and lower headers, respectively; And at least one baffle disposed such that fluid flowing in the evaporator in one of the manifolds continuously flows through the unit in at least two passes, the tube having a size smaller than the header in the transverse direction of the header, Evaporators in which the units are stacked and assembled in alignment with the corresponding tubes inside. 8. The evaporator of claim 7, wherein the manifold is a tube and the baffle blocks and blocks the interior of the corresponding tube. 8. The evaporator of claim 7, wherein the unit is assembled to form a core having a core depth of about 2 inches or less, wherein the fins are meandering fins and at least about 18 fins per inch are installed in the tube. . A plurality of heat exchange units, each heat exchange unit consisting of a long upper and lower header and a plurality of tubes mounted along their lengths between the headers and extending side by side therefrom; A first manifold in fluid communication with some headers and a second manifold in fluid communication with the remaining headers; And a meander-shaped tweezers installed between adjacent tubes of each unit, wherein the tubes have a size smaller than the header in the transverse direction of the header, and the units are aligned and stacked with each other with corresponding tubes therein, Assembled to form a core, the core having a depth of about 2 inches or less, and the fin having a fin density of at least about 18 fins per inch. A plurality of heat exchange modules, each heat exchange module consisting of long and parallel first and second headers and a plurality of tubes mounted along their lengths between the headers and extending side by side therefrom; Pins installed between adjacent tubes of each module; A first manifold in fluid communication with some headers at one end and a second manifold in fluid communication with some headers at one end; And a baffle positioned in the header to allow fluid flowing in the evaporator to flow continuously through each module portion in at least two passes, the tube having a size smaller than the header in the transverse direction of the header, the module being An evaporator that is stacked, assembled and aligned with each other with corresponding tubes on the inside.

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