Heat exchanger

Abstract: A heat exchanger (200), particularly a method and a construction for assembling a partition plate (70) in a header pipe (130) are disclosed. A slit (131) passing through the inside of header pipe (130) is slitted on the circumference of header pipe (130) in a first step. Nextly, the projections (131c,131d) projecting toward the outside from a header pipe (130) is formed at the both ends of slit (131) by enlarging slit. Thereafter, a partition plate (70) is inserted into header pipe (130) through the opening (132) of a slit (131), that is, the space between the both projections. The both projections (131c,131d) are respectively bent toward the circumference of a partition plate (70) which is inserted into a header pipe (130), and support a partition plate (70) within a header pipe (130) in a final step. Thus, a partition plate (70) within a header pipe (130) is fixedly supported and is prevented moving toward the opening of a slit (131). Therefore, even if the shock and the vibration propagate a header pipe, a partition plate is fixedly supported within a header pipe and is prevented falling from a header pipe and then the occurrence of space between the inner surface of a header pipe and partition plate is also prevented.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger, and more particularly, to a method and a construction for assembling a partition plate in header pipe of heat exchanger for use as an evaporator or a condenser for an air conditioner, a radiator or heater core for a vehicle, or other type heat exchanger. 2. Description of the Prior Art With reference to FIG.1, a conventional refrigerant circuit for use, for example, in an automotive air-conditioning system is shown. Circuit 1 includes compressor 10, condenser 20, receiver or accumulator 30, expansion device 40, and evaporator 50 really connected through pipe members 60 which link the outlet of one component with the inlet of a successive component. The outlet of evaporator 50 is linked to the inlet of compressor 10 through pipe member 60 so as to complete the circuit. The links of pipe members 60 to each component of circuit 1 are made such that the circuit is hermetically sealed. In operation of circuit 1, refrigerant gas is drawn from the outlet of evaporator 50 and flows through the inlet of compressor 10, and is compressed and discharged to condenser 20. The compressed refrigerant gas in condenser 20 radiates heat to an external fluid flowing through condenser 20, for example, atmospheric air, and condenses to the liquid state. The liquid refrigerant flows to receiver 30 and is accumulated therein. The refrigerant in receiver 30 flows to expansion device 40, for example, a thermostatic expansion valve, where the pressure of the liquid refrigerant is reduced. The reduced pressure liquid refrigerant flows through evaporator 50, and is vaporized by absorbing heat from a fluid flowing through the evaporator, for example, atmospheric air. The gaseous refrigerant then flows from evaporator 50 back to the inlet of compressor 10 for further compression and recirculation through circuit 1. With further reference to FIGS.2 and 3, a prior art embodiment of condenser 20 as disclosed in Japanese Utility Model Laid-Open SHO 63-49193 is shown. Condenser 20 includes a plurality of adjacent, essentially flat tube 21 having an oval cross-section and open ends which allow refrigerant fluid to flow therethrough. A plurality of corrugated fin units 22 are disposed between adjacent flat tubes 21. Circular header pipes 23 and 24 are disposed perpendicularly to flat tubes 21 and may have, for example, a clad construction. Header pipes 23 and 24 have slits 25 disposed therethrough. Flat tubes 21 are fixedly connected to header pipes 23 and 24, and are disposed in slits 25 such that the open ends of flat tubes 21 communicate with the hollow interior of header pipes 23 and 24. Header pipe 23 has an open top end and an open bottom end. The open top end and the open bottom end are respectively sealed by inlet union joint 23a and outlet union joint 23b which are fixedly and hermetically connected thereto. Inlet union joint 23a is linked to the outlet of compressor 10. Outlet union joint 23b is linked to the inlet of receiver 30. Partition walls 23c are fixedly disposed within header pipe 23 at a location about upper and lower way along its length of header pipe 23 and divide header pipe 23 into upper chamber 231 and middle chamber 232 and lower chamber 233. Header pipe 24 has a closed top end and a closed bottom end. Partition wall 24a is fixedly disposed within header pipe 24 at a location about midway along its length of header pipe 24 and divides header pipe 24 into upper chamber 241 and lower chamber 242 which is isolated from upper chamber 241. The location of partition wall 24a is lower than the location of upper partition wall 23c and is higher than the location of lower partition wall 23c. In operation, compressed refrigerant gas from compressor 10 flows into upper chamber 231 of header pipe 23 through inlet union joint 23a, and is distributed such that a portion of the gas flows through each of flat tubes 21 which are disposed above the location of partition wall 23c, and into an upper portion of upper chamber 241. The refrigerant in the upper portion of upper chamber 241 flows downward into a lower portion of upper chamber 241, and is distributed such that a portion flows through each of the plurality of flat tubes 21 disposed below the location of partition wall 23c and above the location of partition wall 24a, and into upper portion of middle chamber 232 of header pipe 23. The refrigerant in an upper portion of middle chamber 232 flows downward into a lower portion, and is distributed such that a portion flows through each of the plurality of flat tubes 21 disposed below the location of partition wall 24a and above the location of partition wall 23c, and into upper portion of lower chamber 242 of header pipe 24. The refrigerant in an upper portion of lower chamber 242 flows downward into a lower portion, and is distributed such that a portion flows through each of the plurality of flat tubes 21 disposed below the location of partition wall 23c, and into lower chamber 233 of header pipe 23. As the refrigerant gas sequentially flows through flat tubes 21, heat from the refrigerant gas is exchanged with the atmospheric air flowing through corrugated fin units 22. Since the refrigerant gas radiates heat to the outside air, it condenses to the liquid state as it travels through tubes 21. The condensed liquid refrigerant in lower chamber 233 flows out therefrom through outlet union joint 23b and into a receiver 30 and the further elements of the circuit as disclosed above. As shown in FIG.3, header pipe 23 includes slits 26 formed on an opposite side thereof from slits 25 and at a vertical location between two adjacent slits 25. partition plate 27 forming a partition wall 23c within header pipe 23 includes smaller diameter semi-circular portion 271 and larger diameter semi-circular portion 272 integrally formed such that two semi-circular portions are joined at their chordal surfaces. Portion 271 has a diameter substantially equal to the inner diameter of header pipe 23 and portion 272 has a diameter substantially equal to the outer diameter of header pipe 23. partition plate 27 is disposed in slit 26 such that portion 271 fits flush against the inner surface of header pipe 23 and the outer surface of portion 272 is disposed such that the end portions 272a of portion 272 fit flush against the end portions 262 of a slit 26 so as to prevent a partition plate 27 moving toward the inside of a header pipe 23 and to be substantially even with the outer surface of header pipe 23. Both partition plates 27 and header pipe 23 are brazed with the other members constituting a condenser 20 in the brazing kiln so as to ensure that no leakage of refrigerant fluid occurs between the interior portions which are separate by partition plate 27, or from the interior of header pipe 23 to the outside. With reference to FIG.4, the inside of header pipe 23 is made of aluminum metal 23d and the outside of header pipe 23 is made of an alloy of aluminum and silicon 23e layered on the circumference of aluminum metal 23d, of which the melting point is lower than the melting point of aluminum metal 23d. When a condenser 20 is manufactured, partition plates 27 are inserted to the interior of header pipe 23 through slits 26. Thereafter, a condenser 20 is entered and is heated within the brazing kiln. As the melting point of an alloy of aluminum and silicon 23e is lower than the melting point of aluminum metal 23d, alloy of aluminum and silicon 23e is melted by heat within the brazing kiln and brazes partition plate 27 within header pipe 23. However, partition plate 27 is inserted into header pipe 23 through slit 26 by using no supporting and adhered means, and is merely supported by the end portions 262 of slit 26 in order to prevent a partition plate 27 moving toward the inside of a header pipe 23 and the layer portion 261 of slits 26 in order to prevent the partition plate 27 moving up and down and the inner surface of header pipe 23 as shown in FIG.5. Therefore, partition plates 27 are easily unsteady and particularly moves toward the outside of a header pipe 23 before a condenser 20 is heated and partition plate 27 is brazed with the other members constituting a condenser 20 within the brazing kiln, slippage or falling of partition plates 27 easily occur by a little vibration and a little shock. When a condenser 20 is heated within the brazing kiln in a condition that the slippage or the falling of partition plates 27 occurs, for example, a condenser 20 not being able to form the partition walls 23c or having the space between partition walls 23c and the inner surface of header pipe 23 is manufactured. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a heat exchanger having a method and a construction for assembling a partition plate in header pipe of heat exchanger which can prevent the slippage and the falling of partition plate before partition plate is brazed within the brazing kiln. To achieve the above object, a method for manufacturing a header pipe of a heat exchanger according to the invention is defined by the features of claim 1. According to this method the header pipe is formed as a cylindrical shape with a plurality of connection holes for receiving the heat exchanger tubes and with at least one slit for inserting the partition plates therein. The method comprises the steps of a slitting step for forming the slit passing through the inside of a header pipe on the circumference of a header pipe of which the length between the both end portions is shorter than the diameter of partition plate; a slit enlarging step for forming the both ends of slit to the projections by enlarging a slit and by cutting open the ends of slit; a partition plate inserting step for inserting a partition plate into a header pipe through the opening of a slit enlarged; and projections bending step for pressing the circumference of partition plate and for fixedly supporting a partition plate within a header pipe in order to prevent the motion toward the outside of a header pipe. In addition, a heat exchanger including a header pipe according to the invention is defined by the features of claim 2. In this heat exchanger the header pipe is formed as a cylindrical shape with a plurality of connection holes for receiving the heat exchanger tubes and with at least one slit for inserting the partition plates therein. The construction comprises a slit forming on the circumference of a header pipe and passing through the inside of a header pipe; a partition plate inserted into a header pipe through a slit; and a pair of projections formed on the both ends of slit and pressing the circumference of a partition plate and fixedly supporting a partition plate within a header pipe in order to prevent the motion toward the outside of a header pipe. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 a schematic block diagram of a refrigerant circuit in accordance with the prior art. FIG.2 is an elevational view of the condenser shown in the refrigerant circuit of FIG.1. FIG.3 is a perspective view of certain elements of the condenser shown in FIG.2. FIG.4 is a partial cross-sectional view along line 1 - 1 in FIG.2 with flat tubes and fin units omitted. FIG.5 is a partial cross-sectional view along line 2 - 2 in FIG.2 with flat tubes and fin units omitted. FIG.6 is a perspective view of the condenser in accordance with an embodiment of the present invention. FIG.7A is a partial cross-sectional view showing a slitting step in the method according to the embodiment of the present invention. FIG.7B and 7C are partial cross-sectional views showing a slit enlarging step in the method according to the embodiment of the present invention. FIG.8 is a perspective view showing a partition plate inserting step in the method according to the embodiment of the present invention. FIG.9A is a partial cross-sectional view showing an inserting step in the method according to the embodiment of the present invention. FIG.9B and 9C are partial cross-sectional views showing a projections bending step in the method according to the embodiment of the present invention. FIG.10 is a cross-sectional view of a header pipe showing a condition of a partition plate supported within a header pipe according to the embodiment of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawings, FIGS.6-10 show a method and a construction for assembling a partition plate in a header pipe of a condenser according to an embodiment of the present invention, and the condenser manufactured by the method. In the Figures, the same reference numerals are used to denote corresponding elements shown in the prior art figures. Therefore, a complete explanation of those elements is omitted. With reference to FIG.6, a condenser in accordance with an embodiment of the present invention. Condenser 200 includes a plurality of flat or planar tubes 21, and a plurality of corrugated fin units 22 alternately arranged and forming heat exchange region 200a. Flat tubes 21 are preferably made of aluminum and have a multi-hollow construction, that is, flat tubes 21 includes a plurality of longitudinally disposed dividing walls such that each flat tube 21 includes a plurality of parallel flow paths. This construction increases the surface area the refrigerant fluid contacts as it flows through the flat tubes 21. Flat tubes 21 are disposed in slots 25 in header pipes 130 and 140 disposed at the opposite ends of the flat tubes 21 as discussed with respect to FIG.3. Open-ended header pipes 130 and 140 are cylindrical shape. Although not shown in FIG.6, the inside of header pipes 130 and 140 are made of aluminum metal and the outside of header pipes 130 and 140 are made of an alloy of aluminum and silicon of which the melting point is lower than the melting point of aluminum metal as discussed with respect to FIG.4. partition wall 71 is disposed at an upper location within a header pipe 130, partition wall 72 is disposed at a lower location within a header pipe 140. An upper plug 15 is disposed in the top open end of header pipe 130 and a lower plug 16 is disposed in the lower open of header pipe 130. A partition wall 71 and an upper plug 15 and a lower plug 16 divide header pipe 130 into upper fluid chamber 130a and lower fluid chamber 130b. Inlet pipe 230 is disposed through header pipe 130 and links upper fluid chamber 130a with further elements of the refrigerant circuit. The two chambers 130a and 130b are isolated from each other. Outlet pipe 240 is also disposed through a header pipe 140 and links lower fluid chamber 140b with further elements of the refrigerant circuit. Header pipe 140 includes a partition wall 72 disposed therein at a location which is lower than a location of a partition wall 71, and upper plug 17 and lower plug 18 respectively disposed in the top open end and the bottom open end. Partition wall 72 and upper plug 17 and lower plug 18 divide header pipe 140 into upper fluid chamber 140a and lower fluid chamber 140b which are isolated from each other. In operation, compressed refrigerant gas from compressor flows into upper fluid chamber 130a of a header pipe 130 through inlet pipe 230, and is distributed such that a portion of the gas flows through each of flat tubes 21 which are disposed above the location of a partition wall 71, and flows into an upper portion of upper fluid chamber 140a. The refrigerant in the upper portion of upper fluid chamber 140a is distributed such that a portion flows through each of a plurality of flat tubes 21 disposed below the location of a partition wall 71 and above the location of a partition wall 72, and flows into upper portion of lower fluid chamber 130b of a header pipe 130. The refrigerant in an upper portion of lower fluid chamber 130b flows downward into a lower portion of a lower fluid chamber 130b, and is distributed such that a portion flows through each of a plurality of flat tubes 21 disposed below the location of partition wall 72, and flown into lower fluid chamber 140b of a header pipe 140. As the refrigerant gas sequentially flows through flat tubes 21, heat from the refrigerant gas is exchanged with the atmospheric air flowing through corrugated fin units 22. Since the refrigerant gas radiates heat to the outside air, it condenses to the liquid state as it travels through flat tubes 21. The condensed liquid refrigerant in lower fluid chamber 140b flows out therefrom through outlet pipe 240 and flows into a receiver and the further elements of the refrigerant circuit. FIG.7A shows a slitting step of the method for assembling a partition plate in a header pipe of heat exchanger, for example, a condenser. Firstly, a header pipe 130 is placed and supported in a semicircular groove 81 formed on a die 8 of a press machine. Die 8 includes a pair of blade portions (not shown) which are formed at the opposite upper inner end portions of semicircular groove 81, respectively so as to face each other. Secondly, a punch 91 positioned above a groove 81 falls and presses and slits on the circumference of a header pipe 130 passes through the inside of a header pipe 130. Thus, a slit 131 passing through the inside of a header pipe 130 is formed on the circumference of a header pipe 130. The length between the end portions 131a and 131b of a slit 131 is shorter than the diameter of a partition plate 70 as shown in FIG. 8-10. After the slitting step, the method proceeds to a slit enlarging step as shown FIGS.7B and 7C. In this step, as shown in FIG.7B, a metallic mold 92 formed U-shaped is positioned above a slit 131 of header pipe 130. The width W of a metallic mold 92 is as long as the width of a groove 81, or is a little shorter than the width of a groove 81. And further, the curvature of a metallic mold 92 is equal to the curvature of a groove 81. Nextly, as shown in FIG.7c, a metallic mold 92 falls on a slit 131 and presses the end portions 131a and 131b. When a metallic mold 92 falls, a pair of end portions 131a and 131b of slit 131 are cut by the pair of blade portions along the circular surface of a metallic mold 92 while they are stretched outwardly. Metallic mold 92 falls till metallic mold 92 fits on the circular inner surface of a header pipe 130. As a result, as shown in FIGS.8 and 9A, the end portions 131a and 131b enlarged form a part of projections 131c and 131d projecting toward the outside from the circumference of a header pipe 130, and as shown in FIG.9A, a U-shaped portion 132 for receiving a partition plate is formed within the inside of header pipe 130 and a groove 133 for fitting a partition plate in is formed on the circular inner surface along a U-shaped portion 132. The opening 131e, that is, the length between the projections 131c and 131d is as long as, or is a little longer than the diameter of a partition plate 70. After a slit enlarging step, the method proceeds to a partition plate inserting step as shown in FIG.8 and 9A. In this step, an upper portion of a U-shaped portion 132 between the projections 131c and 131d is an opening 131e. A partition plate 70 is formed circular shape. A partition plate 70 is inserted into a U-shaped portion 132 through the opening 131e and is fitted into a groove 133 and is supported by a U-shaped portion 13 and a groove 133. The diameter of a partition plate 70 is as long as the width of U-shaped portion 132 or is a little shorter than the width of a U-shaped portion 132, that is, the diameter of a partition plate 70 is longer than the inside diameter of a header pipe 130. Therefore, the inside of a header pipe 130 is perfectly partitioned into a plurality of chambers by a partition plate 70. And further, as a partition plate 70 is circular shape, a partition plate 70 can be inserted into a header pipe 130 regardless of the inserting direction of a partition plate 70. As a result, the worker can easily insert a partition plate 70 into a header pipe 130. After a partition plate inserting step, the method proceeds to the projections bending step as shown in FIG.9B and 9C. In this step, as shown in FIG.9B, a tool 93 is positioned above an opening 131e, that is, above the upper circular surface of a partition plate 70 and the projections 131c and 131d. The width W2 of a tool 93 is as long as the width of the opening 131e or is a little shorter than the width of the opening 131e. The lower portion 93a of a tool 93 is curved shape. Firstly, a tool 93 falls toward the opening 131e, and presses the upper circular surface of a partition plate 70 and the projections 131c and 131d. While a tool 93 falls, the projections 131c and 131d pressed by a tool 93 are gradually bending toward the inside, that is, toward the circumference of a partition plate 70 along the lower portion and a partition plate 70 pressed by a tool 93 is gradually fitting into a groove 133. And further, the lower portion 93a of a tool 93 has the fixed curvature which fits on the circumference of partition plate 70 and the projections 131c and 131d when a tool 93 presses the said members. Thus, as shown in FIG.9C, the projections 131c and 131d bent by a tool 93 is fitted on the circumference of partition plate 70 and a partition plate 70 is fitted in a groove 133. Therefore, a partition plate 70 is fixedly supported in U-shaped portion 132, that is, within a header pipe 130 by the projections 131c and 131d. FIG.10 shows the condition of a partition plate 70 assembled in a header pipe 130 by the above method. As shown in FIG.10, the projections 131c and 131d press the upper circular surface of a partition plate 70 and support a partition plate 70 within a header pipe 130 and prevent a partition plate 70 moving toward the opening 131e. Therefore, even if the shock and the vibration propagate a header pipe 130, a partition plate 70 is prevented moving from the fixed location to the opening 131e by the projections 131c and 131d, and perfectly partitions the inside of a header pipe 130 into a plurality of chambers. A header pipe 130 as shown in FIG.10 and the other members constituting a condenser are assembled into a condenser, and a condenser assembled is carried into a brazing kiln and a condenser is manufactured by heating and brazing in a brazing kiln. When a condenser is carried into a brazing kiln, the shock and the vibration have propagated a header pipe 130 and the other members of a condenser and a partition plate 70 performs to move from the fixed location. However, as the upper circular surface of a partition plate 70 is pressed and is supported by the projections 131c and 131d, a partition plate 70 is prevented moving toward the opening 131e from the fixed position and falling from a header pipe 130 to the outside. Therefore, a partition plate 70 perfectly partitions the inside of a header pipe 130 and forms a partition wall, and a condenser not having a partition wall or having the space between a partition wall and the inner surface of a header pipe 130 and the like is prevented manufacturing.

Claims: A method for manufacturing a header pipe of a heat exchanger, said header pipe being formed as a cylindrical shape with a plurality of connection holes thereon for receiving heat exchanger tubes and with at least one partition plate therein for turning a heat medium in said header pipe, the method comprising the steps: forming a slot on said header pipe; stretching a pair of radial ends of said slot outwardly; inserting said partition plate into an inner hollow space of said header pipe so that one portion of a periphery of said partition plate is received on a lower axial end of said slot; bending said stretched pair of the radial ends of said slot inwardly so as to be firmly engaged with said partition plate. A heat exchanger including a header pipe (130), said header pipe being formed as a cylindrical shape with a plurality of connection holes thereon receiving heat exchanger tubes and with at least one slot (131) receiving a partition plate (70) therein, said partition plate turning a heat medium in said header pipe (130), the slot (131) having radial end portions (131a, b) forming inwardly bent projections (131c, d) fixing said partition plate (70). A heat exchanger according to claim 2, characterized in that said partition plate (70) is clad with a brazing material. A heat exchanger according to claim 2 or 3, characterized in that said partition plate (70) is circular shaped. A heat exchanger according to any of the claims 2 to 4, characterized in that said partition plate (70) is positioned so as to be substantially perpendicular to an axis of said header pipe (30).

Inventors: HOSOYA KAZUKI C O SANDEN CORPO, KADO HIROTAKA C O SANDEN CORPO, HOSOYA, KAZUKI, C/O SANDEN CORPORATION, KADO, HIROTAKA, C/O SANDEN CORPORATION
Applicants: SANDEN CORP, SANDEN CORPORATION
Application year: 1992
Main classification: F28F9
IPC codes: F28F9, B21D53