Abstract:
In a refrigerated case for food products, having a display surface and a cool-air current that circulates around the display surface, the air current flows through a filter for filtering out airborne particles, bacteria and the like. The filter covers the clear cross section of the exit opening of a circulation channel.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a refrigerated case for highly-perishable food products, particularly meats. This type of case includes a display surface provided with a circulating current of cooled air. The air current is guided forward, via a circulation channel, across the display surface from the rear side of the case and back to the rear side, where it exits through an exit opening of the circulation channel that extends essentially over the case width and above the rear edge of the display surface. 
     A case of this type is known from, for example, G 83 16 262.3. In this case, a fan that sucks the air from the customer side of the case and blows it into the space surrounding the display surface via an exit opening on the service side is disposed in the floor space below the display surface. To filter airborne particles, etc., out of the circulating air, a hygienic filter is disposed in a downward-leading fall shaft on the customer side of the display surface. Despite this filter, microorganisms such as bacteria, fungus spores and the like inevitably collect and proliferate in the floor space, which constitutes a portion of the circulation channel, as well as in the remainder of the circulation channel. These microorganisms can then reach the display surface, unfiltered, with the air current. The fact that case devices, specifically a vaporizer and a fan, which are easily contaminated and are thus breeding grounds for microorganisms, are disposed in the floor space in the known case—a relatively inaccessible location—further promotes the proliferation of microorganisms in the floor space. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to improve a refrigerated case for food products of the aforementioned type with respect to hygiene. The solution to this object lies in a filter for filtering out airborne particles, bacteria and the like, the filter being flowed through by the circulating air current and being disposed in the exit opening of the circulation channel, completely covering the clear cross section of the channel. This arrangement ensures that the air that enters the space containing the products is essentially free of airborne particles, bacteria and the like. In any event, the air contains fewer such particles than when the circulated air flows through the entire space below the display surface and the adjoining section of the circulation channel, in which case the air can be infiltrated by microorganisms, particularly in the region of the vaporizer, a known breeding ground for microorganisms. A further, essential advantage is that the fan can practically be disposed in the immediate vicinity of the exit opening, upstream behind the filter. A slow and uniform circulating-air current is desirable in refrigerated cases for food products. For this reason, in the known refrigerated case, the fan is disposed relatively far from the exit opening, particularly in the floor space beneath the display surface, to avoid air swirling and local differences in air currents. A filter arranged in accordance with the invention thus has an air-purifying effect and simultaneously acts as an air-baffling element, ensuring a slow, uniform air current. Normally, a vaporizer is also disposed in the floor space, which is problematic in terms of hygiene, especially with inconsistent cleaning intervals, which is not infrequently the case. 
     In contrast, in the filter arrangement of the invention, it is easily possible to clean the fan behind the filter. To this end, the filter merely needs to be detachably, particularly pivotally, secured in the exit opening. It is further advantageous if the fan can pivot out of the exit opening about a pivoting axis that extends in the longitudinal direction of the case. Then the rear side of the fan can also be easily cleaned. It is also advantageous for the fan to be pivotable in this manner if—seen in the flow direction—the vaporizer is located directly behind the fan, so the vaporizer can be easily cleaned with suitable cleaning tools such as long-handled brushes, significantly lowering the inhibitory threshold for a thorough cleaning of the regions that are problematic in terms of hygiene. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in detail by way of embodiments illustrated in the figures. 
     FIG. 1 is a cross-sectional representation of the case with arrows indicating the flow direction of the air current surrounding the display surface; 
     FIG. 2 is an enlarged, detailed representation of region II of FIG. 1; 
     FIG. 3 is an enlarged, cross-sectional representation of the filter; and 
     FIG. 4 is an alternative filter embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The case body  1  contains an essentially horizontal display surface  2  for holding a product  3 , which is represented schematically here by a spatial body. The product-housing space  4  above the display surface  2  is encased by an upwardly-pivotable glass display canopy  5 , only shown schematically here. The consumer views the product  3  in the product-housing space  4  from the front side  6 . 
     A current of cooled air circulates in the flow direction  7  around the display surface  2 , embodied here as a horizontal platform for holding the product  3 . The current is effected from the service side  8  of the case, in the direction of the front side  6 , and across the display surface  2 , in other words, the product  3  lying on the surface. There the air current is diverted downward by the glass display canopy  5 , or is sucked up and supplied to the fall shaft  9  in the floor space  12  between the front wall  10  and a parallel, vertical wall surface  11  adjoining the display surface  2 . The floor space  12  is contained between the display surface  2  and the floor  14 , and the air current is also guided laterally beneath the display surface  2  from the case tub  15 . The circulating air exiting the floor space  12  is supplied to a cooling assembly, which is primarily formed by a vaporizer  16 . The vaporizer  16  is located behind the floor space  12  in an ascent shaft  17 , which represents the end region of the circulation channel  20  formed by the fall shaft  9 , floor space  12  and ascent shaft  17 . The circulating air ascends through the ascent shaft  17  or end region, and completes the described air-circulation cycle. A fan  18  is positioned above the vaporizer  16 . This fan provides the drive for the air circulation. Its blowing direction is oriented diagonally upward. 
     A filter  19  for filtering out airborne particles, bacteria and the like is located behind the fan  18  in the flow direction, that is, upstream, in the exit opening  20   a  of the circulation channel  20 . The filter  19  is acted upon by circulating air that is forced out of the fan  18  and baffled in front of the filter  19 , and therefore distributed uniformly over the entire filter surface. An overpressure dominates in the region of the exit opening  20   a  in front of the filter  19 . The filter  19  covers the clear cross section of the exit opening  20   a,  so that, on the one hand, only filtered air, and particularly air containing essentially no microorganisms, can enter the region of the product-housing space  4 , and on the other hand, a uniform, slowed air current is effected. 
     The exit opening  20   a  has the cross-section shape of a rectangle lying down. It is disposed above the rear edge  21  of the display surface  2 , and extends basically parallel to the display surface  2 . 
     The filter  19  is disposed in a hollow profile  22  that covers the exit opening  20   a  and has a uniform cross-section shape over the case width. The longitudinal axis of the hollow profile  22  extends in the direction of the longitudinal extension of the case width, and therefore perpendicular to the drawing planes of FIGS. 1 through 3. The hollow profile  22  includes two parallel flank walls  23 ,  24 . The two flank walls  23 ,  24  are provided with perforations  25  for permitting a flow-through. The hollow profile  22  forms the casing for the filter material  26 . The two hollow profiles are closed by a cap or plug (not shown). The filter material  26  can be cleaned. For this purpose, the filter  19  can easily be released from its filter position (FIGS. 1,  2 ) and removed from the case body  1 . In the assembled position, the hollow profile  22  has the cross-section shape of a standing rectangle, and the flank walls  23 ,  24  provided with perforations  25  are the longer rectangle sides. A gripping tab  28  adjoins the upper end  27  of the flank wall facing the product-housing space  4 . The gripping tab  28  is produced in one piece with the hollow profile  22  embodied as an extruded profile, with the extrusion direction and the longitudinal axis of the hollow profile extending perpendicular to the drawing planes of FIGS. 1 through 3. A downward-protruding lowering rib  30  adjoins the lower end  29  of the front-side flank wall  24  of the hollow profile  22 . In the closed position (FIGS. 1,  2 ), the lowering rib  30  serves in effecting a form-fit in a receiving groove  31  on the case frame  32 , the groove forming the part of a lifting-lowering closure. In the closed position, the filter  19  rests against a support tab  33  of the case body  1 . To release the filter  19 , the filter is first lifted by its gripping tab  28  in arrow direction  34 , then pivoted counterclockwise downward in arrow direction  35 , whereupon it assumes the pivoted position shown as dashed lines in FIG. 2, and is then removed from the receiving groove  31  of the case frame  32  in arrow direction  36 , that is, it is removed from the case body  1 . The filter is re-inserted in the opposite sequence. FIG. 4 shows an alternative embodiment of a filter  19 . This filter encompasses a carrier  42 , which is perforated to permit an air flow-through. The gripping tab  28  is formed onto the carrier&#39;s upper edge in the assembled state. The lowering rib  30  forms the lower edge of the carrier, which basically has the shape of a rectangle lying down. A C-shaped carrier arm  43 —when seen in section transverse to the longitudinal direction of the case—which forms a receiving groove  44 , is formed on above the lowering rib  30 . A filter element  45  is inserted by its lower edge region into this receiving groove  44 . Spacers  46 , against which the filter element  45  is supported, are formed onto the side of the carrier  42  facing the circulation channel  20 . The filter material  26  of the filter element is basically completely encompassed by a perforated casing  47 . The filter element  45  is divided into a plurality of partial elements in the longitudinal direction of the case. To clean the filter  19 , the carrier  42  is pivoted out of its closed position with the aid of the gripping tab  28 , and the filter element  45  or its individual partial elements can then be removed easily from the receiving groove  44  and cleaned. 
     When the filter  19  is removed, the fan  18  is accessible. The fan  18  is secured to a carrier  38 , which is seated to pivot about a pivoting axis  37  at its edge facing the product space  4 . The pivoting axis  37  extends in the longitudinal direction of the case. When the filter  19  is removed, the fan  19  can be pivoted out of the exit opening  20   a  in arrow direction  39 . The fan then roughly assumes a position  40  that corresponds to that of the filter  19  that is now pivoted out of the exit opening  20   a.  The fan rear side  41  is then readily accessible, and can consequently be cleaned thoroughly. When the fan  18  is in the position  40 , the vaporizer  16  or another cooling assembly used for cooling is accessible, and can undergo a thorough cleaning. 
     A display for determining the filter cleaning time could be realized by an overpressure sensor with sensing elements in the circulation channel, or by an oxygen-content sensor.