HEAT EXCHANGER

Abstract: An evaporator for an automotive air conditioning refrigerant circuit is disclosed. The evaporator includes a plurality of flat pipes through which refrigerant flows, and corrugated metal sheets are disposed between the flat pipes. A plurality of linking members are hermetically fixed at both opening ends of the flat pipes and are also hermetically fixed to each other to facilitate communication between adjacent flat pipes.

Description: This invention relates generally to heat exchangers for refrigerant circuits, and more particularly, to an evaporator for an automotive air conditioning refrigerant circuit. In the past, a serpentine type evaporator, such as shown in Figure 1, has been used as an evaporator in automotive air conditioning refrigerant circuits. As illustrated in Figure 1, serpentine type evaporator 100 includes a serpentined flat pipe 200 having corrugated metal sheets 300 disposed between adjacent portions of the flat pipe. In this type of evaporator, refrigerant flow through the serpentined flat pipe is serial only so that considerable pressure loss takes place within the pipe. This pressure loss then increases the compressor load needed to maintain the appropriate refrigerant ability of the refrigerant circuit. Another prior art evaporator is the laminate type evaporator, disclosed in Japanese Utility Model Application 54-3655, which includes a plurality of thin parallelepiped-shaped tanks. This evaporator requires use of a considerably expensive mold for forming the various tanks. Thus, when the laminate type evaporator is used for an automotive refrigerant circuit, which requires frequent design changes, production costs may be significantly increased. It is an object of this invention to provide an evaporator which can be easily and flexibly (i.e., with respect to the length and number of flat pipes and the refrigerant flow) designed without substantial production costs. JP-A-63-3193 discloses an evaporator of a refrigerant circuit including a plurality of flat pipes through which refrigerant flows, at least one heat receiving plate disposed between the flat pipes and means for linking adjacent ones of the flat pipes to each other at both opening ends of the flat pipes; and, in accordance with the present invention, such an evaporator is characterised in that the linking means comprises a series of pairs of shells, one pair of shells being provided at an end of each pipe and defining a manifold space in communication with the respective pipe; and in that at least one shell of each pair of shells is provided with a communication hole in alignment with a communication hole in an adjacent shell of an adjacent pair for communication between adjacent manifold spaces. In the accompanying drawings: Figure 1 is a front elevation of a serpentine type evaporator in accordance with the prior art. In the drawing, intermediate portions of a corrugated metal sheet are omitted. Figure 2 is a front elevation partly in section of an evaporator in accordance with a first embodiment of this invention. In the drawing, intermediate portions of a corrugated metal sheet are omitted. Figure 3 is a grossly enlarged partial perspective view of a flat pipe. Figures 4 and 5 are partial front elevations of an evaporator in accordance with a first embodiment of this invention. Figure 6 is a grossly enlarged partial perspective view of an evaporator in accordance with a first embodiment of this invention. Figure 7 is a grossly enlarged partially sectional view of an evaporator in accordance with a first embodiment of this invention. Figure 8 is a front elevation partly in section of an evaporator in accordance with a first embodiment of this invention. In the drawing, intermediate portions of a corrugated metal sheet are omitted. Figure 9 is a front elevation of an evaporator in accordance with a second embodiment of this invention. Figures 10 and 11 are partial front elevations of an evaporator in accordance with a third embodiment of this invention. The construction of evaporator 10 of an automotive air conditioning refrigerant circuit in accordance with one embodiment of the present invention is shown in Figure 2. Evaporator 10 includes a plurality of flat pipes 20, corrugated metal sheets 30 disposed between flat pipes 20 and a plurality of linking members 40 located at the opening ends of flat pipes 20. An inner space of flat pipes 20 through which the refrigerant flows is divided into a plurality of small passages by a plurality of vertical partition walls 21, as shown in Figure 3. Corrugated metal sheets 30 are provided for receiving heat from air passing through evaporator 10, and are fixed to the side walls of flat pipes 20 by brazing. Outermost flat pipes 20a, 20b are provided with female screw portions 61, 62 respectively, at one opening end thereof to connect to other apparatus of the refrigerant circuit (not shown). With reference to Figures 4, 5, and 6, linking member 40 includes a pair of shells 41 hermetically fixed to each other at the opening ends thereof by brazing. Each shell 41 comprises a cup-shaped portion 41a and a handle portion 41b. During the fabrication process, the handle portions 41b of a pair of shells 41 are simultaneously hermetically secured to one end of flat pipes 20 by brazing. Cup-shaped portion 41a has a flat bottom surface and a hole 41c is provided therein. Adjacent linking members 40 are fixedly secured to one another at the bottom surfaces of the respective cup-shaped portions 41a by brazing, so that adjacent holes 41c are hermetically linked. The opening area of hole 41c is made sufficiently large to avoid pressure loss. Assembly of evaporator 10 proceeds as follows. First, a plurality of linking members 40 are fixed at both ends of a plurality of flat pipes 20. Then, flat pipes 20 and corrugated metal sheets 30 are alternately piled. Shells 41 are appropriately dimensioned as shown in Figure 7 to ensure against gaps occuring between adjacent linking members 40 and between corrugated metal sheets 30 and flat pipes 20. After piling, the assembled elements are temporarily fixed using a jig to maintain their position. The elements are then placed in a brazing furnace and heated to 600°C (linking members 40 and corrugated metal sheets 30 are formed of a clad aluminum alloy which melts at 600°C) to hermetically fix the various elements to adjacent structure as described above. Linking members 40 are of either a first type 401 or a second type 402. A linking member of first type 401, as shown in Figure 4, includes holes 41c formed in the bottom surface of each of shells 41 of the pair of shells. A linking member of second type 402 is shown in Figure 5 and includes only one hole 41c formed in the bottom surface of one of the shells 41. When only the second type linking member 402 is used, refrigerant flow in evaporator 10 is serial. However, when both first and second type linking members 401, 402 are used, refrigerant in evaporator 10 may flow in parallel. Further, both first and second type linking members 401, 402 can be appropriately used to create both serial and parallel flow of refrigerant in evaporator 10 as shown in Figure 8. By increasing the parallel flow of refrigerant in evaporator 10, pressure loss is reduced. It should be understood that the number of flat pipes 20 and the length of flat pipes 20 can be readily changed within the scope of this invention as shown in Figure 9. Figures 10 and 11 show an arrangement in which the edges of cup-shaped portions 41a of shells 41 are flexibly joined.

Claims: 1. An evaporator (10) of a refrigerant circuit including a plurality of flat pipes (20) through which refrigerant flows, at least one heat receiving plate (30) disposed between the flat pipes and means (40) for linking adjacent ones of the flat pipes to each other at both opening ends of the flat pipes; characterised in that the linking means (40) comprises a series of pairs of shells (41), one pair of shells being provided at an end of each pipe and defining a manifold space in communication with the respective pipe; and in that at least one shell (41) of each pair of shells is provided with a communication hole (41c) in alignment with a communication hole (41c) in an adjacent shell of an adjacent pair for communication between adjacent manifold spaces. 2. An evaporator (10) according to claim 1, wherein one of the shells (41) of at least one of the pairs of shells is not provided with a communication hole (41c). 3. An evaporator (10) according to claim 1 or claim 2, wherein the shells (41) of each pair of shells are flexibly joined.

Inventors: ANDO, NOBUYASU, AOKI, HISAO
Applicants: SANDEN CORPORATION
Application year: 1989
Main classification: F25B39
IPC codes: F28D1, F25B39, F28F9