Abstract:
A cooling device includes a cooling unit ( 10 ) through which a fluid to be cooled, especially hydraulic oil, can flow and a filter unit ( 12 ) for filtering fluid. The cooling unit ( 10 ) and the filter unit ( 12 ) are joined together as one piece. The filter unit ( 12 ) is placed together with the cooling unit ( 10 ) inside a device housing ( 14 ). The cooling device can be constructed in a manner that is considerably more compact and lighter, while having an output that is comparable to that of prior art solutions.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a cooling device with a cooling unit through which flows a fluid to be cooled, especially hydraulic oil, and with a filter unit for filtration of the fluid. 
   BACKGROUND OF THE INVENTION 
   Cooling devices of the type in question can be used for a plurality of applications and are available in the most varied of embodiments. The cooling device systems readily available on the market to date however all have a filter unit flanged to the cooling unit or to tank units connected to cooling units, the respective tank unit then holding the filter element. Thus, conventional cooling devices are generally composed of several components. The independent cooling unit can be connected by corresponding tubing to the independent actual filter unit in producing the cooling device with one another. Faulty connections and fault sources arise in the installation of conventional cooling devices with the indicated tubing. Furthermore, conventional cooling devices are structurally large due to the diversity of their parts, and are accordingly heavy. Such structure is disadvantageous especially for mobile use. 
   SUMMARY OF THE INVENTION 
   Objects of the present invention are to provide improved cooling devices that are compact and light in construction, and avoid possible fault sources in installation. 
   According to the present invention, the cooling unit and the filter unit are connected in one piece to one another. Because the filter unit together with the cooling unit is located in the housing of the device, the conventional multi-part structure is avoided and the cooling device of the present invention can be manufactured in a manner that is considerably more compact and lighter, while still achieving the same performance capacity. Furthermore, by integrating the cooling unit and the filter unit in the device housing, the conventional tubing can be omitted and fault sources are precluded in this way. 
   In one preferred embodiment of the cooling device of the present invention, the filter unit, in the flow direction of the fluid, is located upstream or downstream from the cooling unit and the cooling unit is designed as a plate-shaped finned cooler. Especially for installation spaces that are kept flat, the plate configuration of this type is advantageous. By selective arrangement of the filter unit in the right or left water box of the cooling unit, it is possible to interchange the sequence of cooling unit and filter unit with one another. This selectivity allows extensive matching of the cooling device to the installation conditions on site. Preferably, the device housing is composed of sheet metal parts. However, an embodiment formed as a casting is especially preferred, particularly as an aluminum diecasting. 
   In another preferred embodiment of the cooling device of the present invention, the filter unit is made cylindrical. Fluid supply into the device housing takes place in the upper area of the filter unit. The fluid drains from the cooling unit in its lower area. A favorable flow-through behavior for the fluid can be achieved by the arrangement of fluid feed and drainage of this type. 
   In another especially preferred embodiment of the cooling device of the present invention, the filter element is held in a filter housing, which filter housing is an integral part of the device housing. The filter housing can be matched to the outside contour of the filter element so that for this element, even in the outside peripheral area, reliable support and guidance within the device housing are guaranteed. Preferably, in the filter housing at least two bypass valves are provided which respond at different volumetric flows. Thus, for example, improved matching to variable volumetric flows from 60 l to 160 l can be achieved, with the result that a cooling device can be used in a wide range of applications with different orders of magnitude of fluid volumetric flows without structural changes being necessary here. 
   For an especially environmentally friendly device, the filter element can be formed from materials which can be completely incinerated. Thus, disposal without residue is for the most part achieved. 
   To improve the refrigerating capacity the cooling unit, especially its front side, a motor-fan unit is connected and increases the possible air throughput in the finned cooler. This fan leads to improved cooling results. 
   In another preferred embodiment of the cooling device of the present invention the filter housing can be sealed by a sealing cover. On the filter housing, a connection point is provided for a fouling indicator. The fouling indicator can show the degree of fouling of the filter element. In the clogged state, the fouled filter element should be replaced by a new one. A replacement of this nature takes place with ease of installation and promptly by the upper sealing cover on the filter housing. For stationary and mobile installations of the cooling device, fixing parts allow a detachable connection to stationary components on machines and devices as well as on vehicles. 
   Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings which form a part of this disclosure: 
       FIG. 1  is a front elevational view of a cooling device without a motor-fan unit according to a first embodiment of the present invention; 
       FIG. 2  is a top plan view of the cooling device of  FIG. 1 ; 
       FIG. 3  is a side elevational view of the cooling device of  FIG. 1 ; 
       FIG. 4  is a front elevational view partially in section of the cooling device of  FIG. 1 ; 
       FIG. 5  is an operating diagram of the cooling device of  FIG. 1 ; and 
       FIG. 6  is a side elevational view in section of a cooling device according to a second embodiment of the present invention, to the extent it differs from the first embodiment. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The cooling device has a cooling unit  10  through which a fluid to be cooled, especially hydraulic oil, can flow and a filter unit  12  for filtration of that fluid. As shown especially by  FIGS. 1 and 2  and  FIG. 4 , the cooling unit  10  and the filter unit  12  are connected in one piece to one another. The filter unit  12  together with the cooling unit  10  are located in the device housing  14 . According to the two embodiments shown in the drawings, the filter unit  12  is located, in the flow direction of the fluid, upstream from the cooling unit  10 . The filter unit  12 , however, can also be located, according to one embodiment of the cooling device of the present invention (not shown), in the flow direction of the fluid downstream from the cooling unit  10  and connected to it in one piece within the device housing  14 . 
   Furthermore, as shown in  FIGS. 1 and 4 , the cooling unit  10  is constructed as a plate-shaped finned cooler. To route or convey the cool air, the plate cooler housing  16  folded out in a zigzag shape. Between the fins, border fluid guide channels  18  transport the fluid to be cooled. The air guidance direction by the cooling unit  10  extends perpendicularly to the plane of  FIGS. 1 and 4 , with the fluid transport direction being transversely thereto and therefore in the plane of the Figure. Furthermore, the fluid guide channels  18  are located on top of one another, and discharge on both sides into first and second fluid collecting spaces  20 ,  22 . The structure of the finned cooler of the type in question is generally conventional so that it is not detailed here. The device housing  14  itself in this embodiment is made as an aluminum casting; but it can also be assembled from sheet metal parts in a box shape and assembled into a housing by way of welds. 
   The filter unit  12  is cylindrical. Fluid supply  24  into a first housing part of the device housing  14  takes place in the upper edge area of the filter unit  12 . The fluid drain  26  out of the cooling unit  10  takes place in a lower area of a second housing part of the device housing by way of the fluid collecting space  22 . As seen in  FIGS. 1 and 4 , the rough flow-through direction is from top left to bottom right. The actual filter element  28  comprises conventional filtration materials, for example, a pleated, hollow-cylindrical filter mat surrounding a middle support pipe  30 , and is held in a filter chamber of the filter housing  32  formed as an integral component of the first housing part of the device housing  14 , especially in the form of a casting. As shown in  FIG. 4 , a partition wall is adjacent to and separates the filter chamber from the first collecting space  20 . The replaceable filter element  28  filters dirt out of the fluid supplied by the fluid supply  24 . By filtering dirt out of the fluid by the filter element  28 , cleaned fluid is then conveyed through the cooling unit  10  and cannot form deposits therein which could jeopardize operation of the entire cooling device. 
   In the embodiment as shown in  FIG. 4 , the partition wall of filter housing  32  towards the cooling unit  10  borders the fluid collecting space  20 , and in cross section is essentially L-shaped, like the bordering area of the fluid collecting space  20 . Space  20  extends, like the fluid collecting space  22 , over or along the entire height of the entire device and the cooling unit  10 . The actual filter element  28  stands or rests on the bottom  34  of the integrated filter housing  32 . The bottom has a middle flow-through recess shown in  FIG. 4  providing a fluid-guiding connection between the interior of the filter element  28  and the fluid collecting space  20 . Furthermore, the fouled fluid flows through the filter element  28  from the outside to the inside. The fluid cleaned in this way is relayed by the through-opening in the bottom  34  of the partition wall and the fluid collecting space  20  to the cooling unit  10 . To be able to ensure undisrupted filtration, the filter element  28  is encompassed by the filter housing  32  with a radial distance so that the filter element  28  can be peripherally flushed by the fouled fluid applied to the device by the fluid supply  24 . 
   As seen in  FIG. 4 , in the upper area of the filter housing  32  and diametrically opposite the fluid supply  24  in the wall of the filter housing  32 , on top of one another, two bypass valves  36  are provided with opening and closing characteristics corresponding to one another. The bypass valves  36  ensure that when the filter element  28  is completely clogged, the cooling operation is not interrupted, acting as a sort of emergency supply, as before the supply of the cooling unit  10  with the fluid to be cooled. By using the two bypass valves  36 , a larger range of volumetric flow quantities can be covered with only one cooling device, for example the range from 60 l to 160 l. At low volumetric flows, only one bypass valve  36  responds. In other applications with higher volumetric flow, two bypass valves  35  are necessary if the filter element  28  is completely clogged. 
   The filter element  28 , on its top, discharges into two holding grooves  38  which facilitate removal of the filter element  28  by hand. The filter element  28  preferably comprises materials which can be completely incinerated, so that the clogged and used filter element  28  can be disposed of almost free of residue. For effective cooling operation, the front side of the cooling unit  10  is connected to a motor-fan unit (not shown) used to guide the air flow by the cooling fins  16  to cool down the heated fluid in the fluid guide channels  18  to a definable value. In the area of concrete pumps where these cooling devices are used, the fluid is cooled, for example, from 80° C. to 60° C. On its top, the filter housing  32  can be sealed by the sealing cover  40  fixed by a screw connection  42  on the upper opening edge of the cylindrical filter housing  32 . 
   A connection point  44  for the fouling indicator (not shown) is at a right angle and in the same reference plane next to the fluid supply  24  in the filter housing  32 . The fouling indicator can be connected to the connection point  44 , for example, by an electrical connecting cable  46 , allowing determination of the degree of fouling of the filter element  28 . In the embodiment shown in  FIG. 6 , the support tube or pipe  30  is made modular by individual plastic support tube segments. On the bottom  34 , the filter element  28  is routed in an element receptacle  48  of the filter housing  32 . 
   As especially shown by the plan view in  FIG. 2 , both the cooling unit  10  and the cylindrical filter unit  12  on their back side  50  essentially terminate in a common plane. Perpendicular to that common plane is the connection site  44  for the fouling indicator on the filter housing  32 . The fluid supply  24  and the fluid drain  26  lie in turn in a common plane parallel to the back side  50  of the common termination wall. On the free front sides at the top and bottom on the cooling unit  10 , a bridge-like fastening part  52  is provided to fix the cooling device on stationary components or in a mobile application, for example, by a screw connection which is not detailed. 
   By virtue of the fact that, as indicated, the filter pot or housing with the filter element  28  is an integral component of the cooler in the form of the cooling unit  10 , a compact and light construction is achieved. As a result of the internal fluid routing by the fluid collecting spaces  20  and the fluid guide channels  18 , complex tubing is for the most part avoided and fault sources in installation and maintenance of the cooling device are precluded. As a result of the presence of multiple bypass valves  36 , improved matching with variable volumetric flows, especially from 60 l to 160 l flow quantity, is achieved. The cooling device is environmentally friendly with respect to optimum recycling capacity. Since the filter unit  12  in the flow direction of the fluid to be cooled is located upstream from the plate-shaped finned cooler  10  and because the filter unit  12  extends along the side wall of the finned cooler  10  which is kept free of the fins of the cooler itself, a cooling device is formed which is made plate-shaped, which has a very compact structure, which requires less installation space, and which still ensures a very large amount of refrigeration capacity. Furthermore, in the arrangement of the present invention, the fouled fluid is prevented from clogging the fluid-carrying fins within the plate cooler. 
   While various embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.