Air defrost for low-bed refrigerated display cases, utilizing sill-mounted auxiliary fan

Claim 1

In a low-bed refrigerated display case having rear, bottom, and front walls providing a product well at the top of which an access opening is defined, the walls further providing an air passage that extends about the product well and a discharge grill and a return opening extending along the rear and front edges, respectively, of the access opening, an evaporator coil in the passage, and a circulating fan also mounted in the passage to circulate air through the passage and coil and form an air curtain in movement across access opening from the discharge grill to the return opening during the refrigeration mode of the case, the improvement comprising a discharge sill mounted on the rear wall above the outlet, the sill having a defrost air chamber to which entry is had through inlet ports located adjacent the discharge grille, and from which air may be discharged through outlet ports to the ambient atmosphere surrounding the case; and defrost air fan means mounted in the chamber and adapted for operation during a defrost mode in a direction to draw air into the chamber through the inlet ports and discharge it through the outlet ports, in a quantity such that at least part of the air exiting the discharge grille is discharged through the sill to the surrounding ambient and thereby diminishes the air curtain voluntarily to an extent effective to induce at least some ambient air to enter the return opening.