Patent Publication Number: US-7721796-B2

Title: Heat exchanger for multiple cooling loops

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
   Not applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   REFERENCE TO A MICROFICHE APPENDIX 
   Not applicable. 
   TECHNICAL FIELD 
   The present invention relates to a heat exchanger, and more particularly to a heat exchanger usable in systems having heat exchange loops passing separately through the heat exchanger. 
   BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ART 
   A radiator type heat exchanger is disclosed in EP 818 663 B1, in which two collecting tanks are arranged on opposite sides with longitudinal and end walls, as well as with a number of openings, each of which accommodates a tube through which a medium flows. The collecting tanks have an inlet and an outlet, and one of the collecting tanks has a partition with an opening which can be closed with a plug. Depending on the design of the employed closure plug, the radiator can be designed with or without a low temperature range. EP 818 663 B1 always involves a single cooling loop which is passed through the radiator. However, in systems in which several independent loops exist, heat exchangers such as disclosed in EP 818 663 B1 cannot be readily used unless several such heat exchangers are provided, each separately openable for emptying the associated loops. Such heat exchangers may require corresponding additional expense. Further, emptying of multiple loops may be correspondingly more difficult and time consuming, with it also being possible to inadvertently fail to empty one of the loops. 
   The present invention is directed toward overcoming one or more of the problems set forth above. 
   SUMMARY OF THE INVENTION 
   In one aspect of the present invention, a heat exchanger is provided, including a first collecting tank having an opening through a wall of the first tank, a second collecting tank, and at least one row of tubes extending between the collecting tanks. The tubes having spaces therebetween and the tubes and tanks are adapted to carry a first medium and a second medium is adapted to flow through the space between the tubes. An inlet is provided in one of the collecting tanks, and an outlet is provided in one of the collecting tanks. A first partition divides the first collecting tank and includes an opening therethrough, and a second partition divides the second collecting tank, with the first and second partitions defining separate loops for the first medium when the first partition opening is closed. A discharge device is adapted to selectively open both the first collecting tank opening and the first partition opening or close both the first collecting tank opening and the first partition opening. 
   In one form of this aspect of the present invention, the discharge device selectively opens or closes both openings simultaneously. 
   In another form of this aspect of the present invention, the discharge device includes a rod having one end adapted to plug the first partition opening and the other end plugging the first tank opening, with the rod being mounted for selected removal from the first tank. 
   In still another form of this aspect of the present invention, the discharge device includes a tubular member open on both ends with one open end defining the first partition opening, and a closure plug at the first tank opening adapted to selectively open or close the first tank opening and the other open end of the tubular member. In a further form, the tubular member is shorter than the distance between the first tank opening and the first partition opening, and the closure plug includes a pin whose cross-section generally corresponds to the cross-section of the tubular opening of the tubular member, with the pin being received in the tubular member tubular opening when the closure plug is in the first tank opening. 
   In yet another form of this aspect of the present invention, the first and second partitions are at substantially the same height. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of one face of a vehicle cooling module according to the present invention; 
       FIG. 2  is a schematic cross-sectional depiction of the lower part of the radiator portion of the  FIG. 1  cooling module; and 
       FIG. 3  is a schematic detail view of one side of the lower portion of a radiator portion of a second embodiment of a cooling module according to the present invention. 
       FIG. 4  is a schematic detail view of one side of the lower portion of a radiation portion of a third embodiment of a cooling module according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A first embodiment of a cooling module  10  embodying the present invention is shown in  FIG. 1 , which includes several heat exchangers, all of which may be advantageously designed as all-metal heat exchangers from aluminum. Such heat exchangers can be recycled without costly material separation, thereby meeting the requirements of both automobile manufacturers and the public, and has been standard for many years. 
   In the  FIG. 1  embodiment, a charge air cooler  20  is located above a radiator  24 . The cooling air flows through the cooling module  10 , which is usually arranged in the front area of the vehicle. A condenser for the air conditioner and, if necessary, additional heat exchangers (e.g., an oil cooler) are not shown but may also be situated in front of the radiator  24  in the direction of air flow. 
   The left collecting tank  30  of the radiator  24  has an inlet  40  for the coolant and the right collecting tank  34  has a corresponding outlet  42 . However, the inlet  40  and outlet  42  may, alternatively, be situated on the same collecting tank such as is known in the art. This described design represents part of a first loop otherwise not further shown. 
   An additional loop separate from that which passes through the inlet  40  and outlet  42  as described above is also advantageously provided, but is also not otherwise further shown beyond the portion in the cooling module  10  shown in  FIG. 1 . Specifically, the coolant from this additional loop enters the lower part of the radiator  24  via inlet  46  on the right collecting tank  34  and leaves this lower part via outlet  48  on the left collecting tank  30 . 
   Since the two loops (not further shown beyond the cooling module  10 ) are independent of each other, it should be appreciated that the flow direction is arbitrary, and the flow direction described and shown by the arrows in  FIG. 1  are merely exemplary. 
   The coolant, which flows through the lower part of the radiator  24  (between inlet  46  and outlet  48 ), leaves it with a lower temperature, and may therefore be described as “low temperature flow”. The coolant which flows through the upper part of the radiator  24  (between inlet  40  and outlet  42 ) may be described as “main coolant flow” due to the fact that the first loop there has a much larger mass flow rate (such as may commonly be used to cool the drive machine). 
     FIG. 2  illustrates the lower part of the radiator  24  somewhat more closely, with some details left out for clarity of illustration. The radiator  24  has one or more rows of flat tubes  50 , with corrugated ribs  54  or the like through which the cooling air flows situated between the flat tubes  50 . The lower part of radiator  24  is bounded by a side part  60 , which connects both collecting tanks  30 ,  34 . Side parts  60 , flat tubes  50 , corrugated ribs  54  and collecting tanks  30 ,  34 , like the other heat exchangers of the cooling module, may be advantageously designed with solder connections so that intimate contact is present to permit efficient heat exchange between the cooling air and coolant. 
   As illustrated in  FIG. 2 , the mentioned two loops are separated by a partition  64  in the left collecting tank  34  and an additional partition  66  in the right collecting tank  30 . This separated flow is indicated by the flow arrows with the solid (top) and dashed lines (bottom) in  FIG. 2 . 
   In accordance with the present invention, an opening  70  is present in one partition  64 , which opening  70  is closed as long as the discharge device  74  remains in the closed position depicted in  FIG. 2 . Moreover, the discharge device  74  simultaneously closes an opening  76  in the wall of collecting tank  34  in this position. Thus, it should be appreciated that the discharge device  74  will maintain the integrity of the tank  30  when in the position illustrated so as to allow for separate closed flow for both loops, and that the discharge device when removed will open both openings  70  and  76  so that hydraulic separation between the loops is eliminated and the contents of both loops can be readily emptied when so desired. 
     FIG. 3  shows an alternative of the above described embodiment, in which only a cut-out portion of the lower left side of the radiator  24  is depicted. In this embodiment, the discharge device  74   a  and its operation differ, but the rest is otherwise substantially identical to the  FIG. 2  embodiment. 
   Specifically, in the  FIG. 3  embodiment, the discharge device  74   a  includes two parts: a closure plug  80  and a tubular member  84 . The closure plug  80  sits in the opening  76  in the bottom wall of collecting tank  34 , and has a pin  88  which blocks the passage opening  90  in the tubular member  84 . It should be appreciated that removing the closure plug  80  from the tank bottom wall opening  76  will allow both loops to be emptied, with liquid from the upper loop flowing through the passage opening  90  in the tubular member  84 , and then draining through opening  76  along with liquid from the lower loop which will also drain through the opening  76 . The tubular member  84  can thus provide such operation to empty both loops without requiring that its position be changed. 
   It should be appreciated that the present invention provides an inexpensive structure which may be conveniently and reliably maintained, with separate heat exchange loops easily emptied when desired. Moreover, the present invention is particularly well suited for applications in which the same media (e.g., coolants) are present in both loops, as the emptied media are then of the same type and can therefore be disposed of together appropriately. 
   Further, the present invention is particularly advantageous for use in so-called “all-metal heat exchangers”, which also have collecting tanks made of metal (e.g., aluminum), because an additional opening in the wall of the collecting tank is avoided. Such openings can be expensive to product in such collecting tanks. 
   Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.