WO2007037670A1

WO2007037670A1 - Heat exchanger

Info

Publication number: WO2007037670A1
Application number: PCT/MY2006/000007
Authority: WO
Inventors: Seng Ong Liow
Original assignee: SEASONAIR (M) Sdn Bhd
Current assignee: SEASONAIR (M) Sdn Bhd
Priority date: 2005-09-30
Filing date: 2006-08-30
Publication date: 2007-04-05
Anticipated expiration: 2008-03-30
Also published as: RU79990U1; CN201173710Y; TW200712401A

Abstract

There is disclosed a heat exchanger (10) comprising at least two banks (25, 26) of a plurality of multi cored tubes (20) interconnected in a parallel spaced array by location in header pipes (30, 31) positioned against the ends (21, 22) of the tubes (20). The banks (25, 26) are interconnected by conduits joining adjacent header pipes (30, 31). End plates (40, 41) positioned on the ends of the header pipes (30, 31) align the assembly and seal off the ends of the header pipes (30, 31).

Description

HEAT EXCHANGER

This invention relates to heat exchangers specifically for use as evaporators or condensers in refrigeration or air conditioning circuits .

Refrigeration and air conditioning circuits use heat exchangers in the form of evaporators and condensers to cause expansion and compression of a refrigerant to absorb heat in the evaporator and dissipate heat in a condenser. In either situation there is a need for the refrigerant to pass through a labyrinth that usually comprises a core of laminated plates of coils of heat conductive metal to define a large cross-sectional area over which the coils are exposed to atmosphere to facilitate either the heat absorption or heat dissipation. The labyrinth of laminated plates are mechanically stamped and formed by multi- stages precision tooling and brazing. Due to the complexity in design, failure rate of brazing a laminated core is very high, usually more than 8%. Since the size of the laminated core is fixed, there is no provision for qualities such as humidity of the conditioned or refrigerated air to be regulated or monitored to suit the specific applications. Similarly, it is not possible to change the capacity of the core except a complete tooling change. Pressure drop across the laminated coil is high and often requiring a high powered fan which elevates the noise level is used. These arrangements also suffer from inflexibility due to the fixed position of the refrigerant flow patterns, fluid passageways, inlet and outlet.

It is these issues that have brought about the present invention in which the object is to introduce a heat exchanger that provides flexibility and efficiency of manufacture. According to the present invention there is provided a heat exchanger comprising at least two banks of a plurality of multi cored tubes interconnected in a parallel spaced array by location in header pipes positioned against the ends of the tubes, the banks being interconnected by conduits joining adjacent header pipes, and end plates positioned on the ends of the header pipes to align the assembly and seal off the ends of the header pipes.

Preferably, the heat exchanger according to claim 1, wherein the inlet and outlet for refrigerant are positioned spaced apart in one or more of the header pipes .

The characteristics of the heat exchanger may be varied by altering the length of the tubes and the spacing of the banks of tubes.

Preferably, fins folded into a flat block are located between the spacing between the parallel array of tubes.

In a preferred embodiment, a heat exchanger assembly comprises at least two heat exchangers of the kind described above joined by conduits between two headers of each heat exchanger so that each heat exchanger is orientated in a different plane.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawing in which:

Figure 1 is a perspective exploded view of a heat exchanger comprising two banks of tubes; Figure 2 is a perspective view of the assembled heat exchanger of Figure 1 from one side;

Figure 3 is a perspective view of the assembled heat exchanger of Figure 1 from the other side;

Figure 4 is a front elevational view of the heat exchanger of Figure 1;

Figure 5 is a cross sectional view along the lines A-A of Figure 4;

Figure 6 is a cross sectional view along the lines B-B of Figure 4;

Figure 7 is a cross sectional view along the lines C-C of Figure 4;

Figure 8 is a cross sectional view along the lines D-D of Figure 4;

Figure 9 is a cross sectional view along the lines E-E of Figure 4;

Figure 10 is an exploded view of a heat exchanger comprising three banks of tubes;

Figure 11 is a perceptive view of the assembled heat exchanger of Figure 10 from one side;

Figure 12 is a perceptive view of the assembled heat exchanger of Figure 10 from the other side;

Figures 13A, 13B and 13C are respectively perspective and side elevational views of a direction controller of the heat exchanger shown in Figures 1-12; Figure 14 is a perspective view of another direction controller;

Figures 15A and 15B are respectively perspective and side elevational view of the an end plate that forms part of the heat exchanger;

Figure 16A and 16B are respectively perspective and side views of another form of end plate;

Figure 17A and 17B are respectively side and plan views of a flat tube that forms part of the heat exchanger, and

Figure 18A and 18B are respectively perspective and side elevational views of a fin that forms part of the heat exchanger.

Figure 19 is a perspective view of a heat exchanger assembly with heat exchangers in two planes.

Figure 20 is a plan view of the assembly of Figure 19.

Figure 21 is a perspective view of a heat exchanger assembly with heat exchangers in three planes; and

Figure 22 is a plan view of the assembly of Figure 21.

The two embodiments of heat exchanger illustrated in the drawings essentially comprise heat exchangers 10 that are made up of two banks of flat tubes 20 (Figures 1-9) , and three banks of flat tubes (Figures 10-12) . The detailed description relates to the first embodiment shown in Figures 1-9 and since the other embodiments are very similar, only a brief description of those embodiments in included herein. It is also understood that the heat exchanger could include four or more banks of tubes assembled in the same manner as the three bank assemblies shown in Figure 10-12.

As shown in Figure 1 the heat exchanger 10 comprises a plurality of flat tubes 20 that are supported in a parallel spaced apart array by header pipes 30, 31 that are attached to opposite ends 21, 22 of the tubes 20. The assembly is held together by end plates 40, 41 that are positioned at the top and bottom of the heat exchanger 10 to locate and position the header pipes 30, 31. The tubes 20 are arranged in two banks 25, 26 and directional controllers or conduits 50 interconnect the header pipes 30, 31 to interconnect the two banks 25, 26 of tubes. The assembly is completed by a plurality of fins 60 that extend between the gaps between the tubes 20. When the space between two bank changes, the width of the fin 60 which forms the secondary surface of a heat exchanger, may be increased or decreased so that the refrigerated air quality may be designed accordingly.

As shown in Figures 17A and 17B, each tube is fabricated to be multi-cored, to have a central core 21 that is defined by parallel upper and lower surface walls 23, 24 joined by webs 29. The central core 21 defines seven elongate parallel fluid passages 15. Along the sides of each tube are U shaped side connectors 27, 28 that close off the sides of the tube to define two further passageways 16, 17 so that each tube as shown in Figure 17A is substantially flat and defines nine separate fluid passageways 15, 16, 17. The ends 21, 22 of each tube 20 have crimped edges 11 and a slight indent 12. The tubes are preferably extruded in aluminium or aluminium welded tubes with internal turbulators although there is also an option of producing them in brass or copper.

Kach header pipe 30, 31 is a hollow cylinder 33 that on one side has a plurality of parallel spaced rectangular slots 34 in which the ends 21, 22 of the tube 20 can be clipped into position as shown in Figure 8. In this way, the plurality of flat tubes 20 shown in Figure 1 are located within the slots 34 in the header pipes 30, 31 that are mounted on either end of the array to hold the assembly in position as shown in Figure 2. The position of the header pipes 30, 31 is determined by the metal end plates 40, 41 shown in Figures 15A and 15B with recessed apertures 42, 43, 44, 45 spaced apart at either end that locate and position the header pipes 30, 31 to define the orientation of the assembly. A plurality of small, cylindrical pipes form directional controllers 50 shown in Figures 13A, 13B, and 13C and they are arranged to periodically interconnect the header pipes 30, 31 in a spaced apart array at one end as shown in Figure 1. If there is a need to direct the flow within the tubes, namely to prevent or redirect flow, then a second directional controller 51 is positioned between two slots 34 of the header pipe 30, 31 and within the end 21 or 22 of the flat tube 20 to block off flow. This directional controller 51 is shown in Figure 14.

The assembly is completed by a plurality of fins 60, details of which are shown in Figure 18. These fins comprise a labyrinth of bent aluminium shuting 61 that defines a rectangular wafer that can be slid between the gap between the two banks of parallel adjacent flat tubes 20 to complete the assembly as shown in Figure 2.

The assembly is put together in a closely toleranced manner and then brazing is used to complete the assembly and ensure that the heat exchanger defines a fluid tight array for flow of refrigerant.

One of the advantages of the assembly is that the refrigerant inlet 75 and outlet 76 can be positioned in any desired position in either header pipe 30. This considerably improves the flexibility and use of the assembly (see Figures 1 and 2) .

Figures 4-9 particularly illustrates the assembly of components that make up the heat exchanger showing the role of the end plates 40, 41 that have the effect of aligning the header pipes 30 and showing how the flat tubes 20 clip into the slots 34 in the forward face of the header pipes 30. These drawings also show the simple means of positioning an inlet or outlet connection 75, 76 in any one of the header pipes 30 in direct association with any one the flat tubes 20. Furthermore, these drawings show the direction controller 50 that interconnects one bank with another (see Figure 5) and the direction controller 51 that simply prevents or cuts off flow in one bank (see Figure 6) .

The components of the heat exchanger are comparatively simple to construct and the assembly of the heat exchanger is simple to effect and does not require sophisticated tools or highly toleranced componentry. The length of flat tube 20 may vary to increase and decrease the primary surface of the heat exchanger and change the capacity of the heat exchanger. The space between header pipe 30 and 31 may be actuated to suit the need of the secondary surfaces of the heat exchanger. This is essential to ensure that the refrigerated air quality such as humidity may be designed for maximum comfort or for any specific application. The product is very versatile as is evidenced by Figures 10-12 that show an assembly where there are three banks A, B, C of flat tubes 20, each bank having header pipes 30 at opposite ends and held together by end plates 40 that have appropriately positioned recesses to define the position of the pipes. The fin assembly 60 is the same as in the first embodiment but designed to fit across the three banks of tubes between the gaps between the tubes. It is understood that other heat exchangers could have four or more banks of tubes assembled in the same manner as described above. This considerably improves the versatility and capacity of the heat exchanger.

Other modified embodiments of the invention are shown in Figure 19 to 22 which show an assembly of heat exchangers interconnected by 90 degree directional controllers or conduits 52. Different sizes of 90 degree directional controllers are used to ensure that refrigerant flow to second, third and fourth planes heat exchangers are properly regulated. In these embodiments, the capacity of the heat exchanger may be increased without encountering high pressure drop.

Figure 19 and 20 are perspective and plan views of a two plane heat exchanger assembly. Low powered fan (not shown) is used to direct air across the primary stage heat exchanger 10 in direction A. Another low powered fan (not shown) when switched on, "draws" pre- chilled air across the second heat exchanger 11 in direction B and further conditions the air. Directional controllers 52 are used to connect headers 30 on banks

25 and 26 of heat exchanger 10 to headers 30 of another heat exchanger 11. These directional controllers 52 may also be connected at the bottom headers 31 of any heat exchanger.

Figure 21 and 22 are perspective and plan views of a three plane heat exchanger assembly which is meant for multi functions or multi compartment applications. Air enters a central chamber pre-chilled before being redirected out of heat exchangers 11 and 12.

In another embodiment (not shown) the four plane heat exchanger assembly is provided for multi functions application. Air enters the central chamber pre-chilled and is redirected out from heat exchanger 11, 12, and 13. Heat exchanger 12 and 13 may consist of single bank tubes 20 whereas heat exchanger 11 may be constructed using two banks of tubes 20 for heavier load application. '

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A heat exchanger (10) comprising at least two banks (25, 26) of a plurality of multi cored tubes (20) interconnected in a parallel spaced array by location in header pipes (30, 31) positioned against the ends (21, 22) of the tubes (20), the banks (25, 26) being interconnected by conduits joining adjacent header pipes (30, 31), and end plates (40, 41) positioned on the ends of the header pipes (30, 31) to align the assembly and seal off the ends of the header pipes (30, 31) .

2. The heat exchanger (10) according to claim 1, wherein the inlet (75) and outlet (76) for refrigerant are positioned spaced apart in one or more of the header pipes (30, 31) .

3. The heat exchanger (10) according to either claim 1 or claim 2, wherein the flow of refrigerant within a bank of tubes (20) is controlled by one or more direction controllers (51) located in the header pipes (30, 31) to block off flow of refrigerant.

4. The heat exchanger (10) according to any one of the preceding claims, wherein the inlet (75) and outlet (76) may be positioned in the wall of the header pipe (30, 31) or the end of the header pipe (30, 31) through the end plate (40, 41) .

5. The heat exchanger (10) according to any one of the preceding claims, wherein the characteristics of the exchanger can be varied by altering the length of the tubes (20) and the spacing of the banks (25, 26) of tubes .

6. The heat exchanger (10) according to any one of the preceding claims, wherein each tube (20) is substantially flat and defines a plurality of parallel fluid passageways (15, 16, 17) extending along the length of the tube (20) .

7. The heat exchanger (10) according to claim 6, wherein each tube (20) comprises spaced parallel plates interconnected by spaced dividing walls, and end caps secured along each side of the tube to define the plurality of parallel fluid passageways (15, 16, 17) .

8. The heat exchanger (10) according to any one of the preceding claims, wherein fins (60) folded into a flat block are located between the spacing between the parallel array of tubes (20) .

9. The heat exchanger (10) according to any one of the preceding claims, wherein the end of each tube (20) clips into a groove in the header pipe (30, 31) .

10. A heat exchanger assembly comprising at least two heat exchangers (10, 11) according to any one of the preceding claims joined by conduits between headers of each heat exchanger so that each heat exchanger is orientated in a different plane.

11. The heat exchanger assembly according to claim 10, wherein three or four heat exchangers are joined by conduits so that each heat exchanger is orientated in a different plane.