Patent Publication Number: US-4653580-A

Title: Flow tank heat exchanger

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a heat exchanger, more particularly, to an automobile air conditioner cooler with fins and tubes. 
     2. Description of Prior Art 
     In general, fin and tube heater exchangers are of three types. 
     A. Plate fin evaporator coil heat exchanger provides coils with a series of stampings, between which are compressed with folded fin stock and are vacuum soldered. 
     B. Serpentine evaporator coil heat exchanger provides a continuous flat tube with turns going back and forth. Fin stock is compressed between each flat tube length and vacuum soldered in places. 
     C. Tube and fin heat exchanger provides a series of tubing with fin stock around each tubing. 
     Most of these types of heat exchangers are either labor-intensive because of many parts needed to be soldered or too much pressure loss due to the coil design. Accordingly, the primary object of this invention is to provide a low pressure drop coil design and easy assembling process, thus eliminating labor intensive soldering. 
     SUMMARY OF THE INVENTION 
     The present invention is applicable to any circumstance where either heating or cooling is desired. The invention will be described with reference to automobile installation as an example. 
     A heat exchanger according to the present invention comprises a plurality of parallel tubes connected at each end to a tank cap which is pressed over two end plates. A tank cover is welded onto the tank cap forming a tank at each end. Each tank provides an inlet or outlet means for passing refrigerant directly through the parallel tubes, thus reducing refrigerant pressure drop. Fin stock is made from about 0.005&#34; thick aluminum sheet, folded back and forth and placed between tubes. A special designed tube with extrusion on the tubes extending outwardly provides extra surface area for dissipating heat for the automobile air conditioner. A unique process, dieless vibratory assembly process, is employed for assembling the parts of the heat exchanger to a unit by vibration such that the fins are not damaged during assembly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective view of the embodiment of the present invention; 
     FIG. 2 is a fragmentary top plan view of the self-locking tank cap; 
     FIG. 3 is a fragmentary perspective view of the extrusion tube embodiment of the invention; 
     FIG. 4 is a fragmentary perspective view of the aluminum fin stock; 
     FIG. 5 is a fragmentary elevated end view enlarged to show fin stock contact surface for heat transfer; 
     FIG. 6 is a bottom plan view taken along view line 6--6 of FIG. 5. 
     FIG. 7 is a side elevational view taken along view line 7--7 of FIG. 5, and 
     FIG. 8 is a front elevational view of the vibratory assembly forming dieless process used in the embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to the drawing, FIG. 1 shows a perspective view of the assembled heat exchanger. A tank cover 1 is welded on a tank cap 2, to form a sealed tank at each end. The tank cap has rows of flanged openings 3, for connecting to a series of extrusion tubes 4. Each tank cap has flanges to press-fit two end plates 6. Thus, the parallel extrusion tubes 4 are in communication with the tanks. Between the tubes there is disposed a plurality of fins 5 made of aluminum sheet folded back and forth. Projected extrusion 7 on each tube extending outwardly for providing extra surface area so as to increase heat transfer efficiency. 
     In assembling, as shown in FIG. 8, all parts are set in a fixture in assembling order, and by applying vibration with controlled frequencies, the parts are vibrated to fit each other without damaging the thin fins thus the process is economical as well as efficient. First, the end plates, extrusion tubes, and fin between tubes and around extrusions are arranged in a fixture (not shown). Apply vibration at 88 cycles per second of frequency, for about 18 seconds. Press tank caps over extrusion tubes and end plates. Seal tank cap to extrusion tubes and last seal tank caps. 
     While various changes may be made in the detail construction, it is understood that such changes will be within the spirit and scope of the present invention, as is defined by the appended claims.