Abstract:
Apparatus for holding fried food product for a holding time, defined as the time between the completion of cooking and the time that the food product no longer has a desired warmth, crispness and interior moisture for serving to a customer. The fried food is disposed in a holder or bin and subjected to heat from an upper heater, a lower heater and forced hot air that is applied through and across the fried food. The hot air flow serves to evaporate moisture from the fried food surface and to remove water vapor from the region above the fried food, whereby the holding time is extended to about 20 minutes.

Description:
This application claims the benefit of U.S. Provisional Application 60/101,462, filed Sep. 23, 1998. 
    
    
     FIELD OF INVENTION 
     This invention relates to apparatus for the preparation of food products for restaurant service and more particularly to an apparatus and method for keeping fried food product warm for an extended period of time after they have been cooked, but before they are served. 
     BACKGROUND OF INVENTION 
     Deep frying and similar cooking techniques can provide fried food product, such as French fried potatoes, hash brown potatoes, fried chicken nuggets and the like, upon completion of cooking that have desired characteristics of crispness of their exterior and warmth and moistness of their interior. It is generally recognized that crispness of fried foods is adversely affected in a relatively short time after they are cooked due to moisture migrating from the interior of the product to its exterior surface. As a result, the exterior surface becomes moist. The crispness deteriorates to a soggy and/or greasy condition that can result in a taste of the frying medium. This seriously degrades the sensory appeal of the fried food product. The holding time is the time a fried food product can be held after completion of cooking until its crispness, warmth, and interior moisture have deteriorated to the point that it is unsuitable for serving to a customer. 
     One prior art technique of maintaining the desired characteristics of freshly prepared fried foods is to place them in a heated cabinet having doors or drawers. This technique has a disadvantage that the fried food is not easily accessible. Another prior art technique places the fried food product in a holder and applies radiant heat to them. Both of these techniques have been popular as they tend to keep the fried food product warm. However, the crispness deteriorates after a short time due to moisture migration from the product interior to its surface. For commercial versions of these products, the holding time is limited to ten minutes or less before the fried food loses its sensory appeal. 
     U.S. Pat. No. 4,499,818 provides an alternative technique of maintaining surface crispness and interior moisture of fried food product. This patent uses a recirculating hot air system that blows hot air from below the fried food and/or from the sides thereof to both warm the fried food and to evaporate surface moisture. The hot air is returned via a vent that is positioned to one side of the fried food. A problem with this technique is that water vapor forms in the region above the fried food that is out of the air recirculation path. The water vapor condenses and returns moisture to the topmost layer of the fried food. This limits the time that the fried food can maintain its crispness. 
     In the fast food industry, it is desirable to enhance the holding time that fried food maintains warmth, surface crispness and interior moisture to as long as possible. 
     The present invention has a main object of maintaining a crisp surface and a warm moist interior of fried food for as long as possible. 
     Another object of the present invention is to provide an apparatus that effectively removes moisture as well as water vapor from the vicinity of the fried food. 
     Still another object is to provide an apparatus that provides a significant increase in fried food holding time over currently available equipment. 
     Yet another object is to provide a method for warming freshly prepared fried food and removing moisture and water vapor from the vicinity of the fried food. 
     SUMMARY OF INVENTION 
     Apparatus according to the present invention includes a holder having a surface upon which freshly prepared fried food product is disposed. A upper heater is disposed above the fried food product to apply heat thereto in a downward direction. A lower heater is disposed beneath the fried food product for applying heat thereto in an upward direction. An air flow assembly is arranged to apply a forced air flow in a direction generally transverse to said upward and downward directions through and across the fried food product. The air flow is operative to evaporate surface moisture from the fried food product and to remove water vapor from a region above the fried food product. 
     A method according to the present invention involves applying heat in both a downward direction and in an upward direction to the fried food product. A hot air flow is directed through and across the fried food product in a direction generally transverse to the upward and downward directions. The hot air flow operates to evaporate surface moisture from the fried food product and to remove water vapor from a region above the fried food product. 
     In one embodiment of the apparatus and method of the invention, the hot air flow is developed from a fresh supply of ambient air and is deflected back to ambient after passing across or through the fried food product. In another embodiment of the apparatus and method of the invention, the hot air flow is recirculated. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     Other and further objects, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference characters denote like elements of structure and: 
     FIG. 1 is a perspective view of a first embodiment of the present invention of an apparatus for holding and maintaining the warmth, moisture and crispness of fried food product; 
     FIG. 2 is a front elevational view of FIG. 1; 
     FIG. 3 is an enlarged cross-sectional view taken along the line  3 — 3  of FIG. 2; 
     FIG. 4 is a partial enlarged cross sectional view taken along lines  4 — 4  of FIG. 3; 
     FIG. 5 is a perspective view perspective view of another embodiment of the present invention of an apparatus for holding and maintaining the warmth, moisture and crispness of fried food product; 
     FIG. 6 is an exploded view of FIG. 5; 
     FIG. 7 is a front elevational view of FIG. 5; and 
     FIG. 8 is a fragmentary view of the assembled exhaust port area of FIG.  7 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIGS. 1 through 3, there is provided an apparatus  10  for maintaining the warmth, moisture and crispness of freshly fried food according to a first embodiment of the invention. Apparatus  10  includes a holder  20 , an upper heater  30 , a lower heater  40  and a forced air flow assembly  50 . 
     Holder  20  has a surface  21  that contains a plurality of apertures  22  arranged to diffuse heat emanating from lower heater  40  as well as to allow grease, crumbs, salt and the like to drop through. A quantity of fried food product  12 , shown as French fried potatoes in FIG. 3, is disposed on surface  21 . Holder  20  has a peripheral upright wall  23  that has a pair of side walls  23 A and  23 B, a front wall  23 C and a back wall  23 D. A box shaped bracket  11  extends upwardly from a top surface  41  of lower heater  40 . Peripheral wall  23  has a rim  24  that rests on the top of bracket  11 . As best seen in FIGS. 2 and 3, bracket  11  serves to dispose surface  21  of holder  20  a short distance above heater  40 . For example, this distance may be on the order of 1 to 3 inches for French fried potatoes. 
     Box shaped bracket  11  may be removable for the purpose of cleaning, particularly if it is used to trap or collect droppings from surface  21  such as grease, crumbs, salt and the like. Alternatively, these droppings could be collected on a separate sheet or in a separate container that is removable for cleaning. Surface  21  may be flat as shown or curved and holder  20  may be rectangular as shown or any other desired shape. 
     Heater  40  may be any suitable heater for applying heat in an upward direction to the underside of surface  21 . Surface  21  transfers this heat for application in an upward direction to fried food product  12  by natural convection. By way of example, heater  40  is shown as a platen having a top surface  41 . Lower heater  40  contains an electrical heating coil  42 , shown schematically in FIG.  3 . Electrical heating coil  42  is disposed below platen surface  41  to heat top surface  41 . 
     Upper heater  30  includes an upright bracket  31  that is mounted to forced air flow assembly  50 . Horizontal bracket  32  extends from upright bracket  31  over holder  20  intermediate side walls  23 A and  23 B. Horizontal bracket  32  contains a radiant heater element  33  that is arranged to radiate heat in a downward direction to fried food  12  as shown by dashed arrows  14  in FIG.  3 . It will be apparent to those skilled in the art that two or more radiant elements may be used. 
     Forced air flow assembly  50  includes a base section  51  upon which heater  40  is disposed. Assembly  50  also includes walls  52  and  53  that extend vertically from base  51  on opposed sides of heater  40 . Base  51  and walls  52  and  53  are either hollow or contain air passageways to provide a recirculating air flow path as shown in FIG. 2 by dashed arrows  54 . Wall  53  contains one or more fans  45  that are arranged to take in air through a set of air intake ports  55  shown in FIG.  1 . Fans  45  accelerate the air flow downward in wall  53 , across base  51  and then upward in wall  52 . The air flow then continues out of wall  52  via a set of air delivery ports  56 . An air heater  46  is disposed downstream of the fans. Air heater  46  is preferably disposed as close to air delivery ports  56  as design limitations permit, preferably in either wall  52  or in base  51 , as shown in FIGS. 2 and 3. 
     Referring to FIG. 4, a baffle  57  and a baffle  58  are positioned to direct the air flow in a direction generally transverse to the upward and downward directions of heat provided by upper and lower heaters  30  and  40 . This direction is through fried food product  12  as shown by arrows  59  and across fried food product  12  as shown by arrows  60 . The air flow deflected through fried food product serves to evaporate moisture that forms on the fried food surface as well as to provide additional heating. The air flow deflected over and across fried food product  12  serves to remove any water vapor formed by evaporation from the region above fried food product  12 . The water vapor either is forced away from the region above fried food product  12  or is swept by the air flow into the air intake ports  55 . 
     The combined heat from upper heater  30 , lower heater  40  and air flow assembly  60  operates to extend the time that fried food  12  is warm enough to be served to customers. The forced hot air flow additionally operates to remove moisture from the surface of fried food  12 , thereby maintaining the surface crispy. The air flow further acts to remove water vapor formed in the region above fried food product  12 . 
     In one design of the first embodiment of the invention, a quantity of three pounds of French fried shoestring potatoes was found to have adequate warmth, crispness and interior moisture after a holding time of about 20 minutes. 
     Referring to FIGS. 5 through 8, a second embodiment of the invention includes an apparatus  100  for maintaining the warmth, moisture and crispness of freshly fried food. Apparatus  100  includes a frame  170 , a holder  120 , an upper heater  130 , a lower heater  140  and a fan or blower  145 . Frame  170  includes a base  151 , air duct pieces  178 ,  180  and  182 , a front wall  174  and a back wall  176 . Lower heater  140  and blower  145  are mounted on base  151 . 
     Air duct pieces  178 ,  180  and  182  and base  151  are joined together to form a passageway that together with lower heater  140  and blower  145  form a forced air assembly. To this end, air duct piece  182  has a flat portion  183  with downwardly extending side panels  184  that are secured to base  151  by any suitable fastener, such as by screws or bolts. Side panels  184  are dimensioned to provide adequate spacing to accommodate lower heater  140 . Air duct piece  182  also has an upwardly extending wall  185  with an air delivery cutout  186  and a baffle  188  positioned in delivery cutout  186 . Baffle  188  is oriented to guide or direct air in a direction that is generally horizontal and/or angled slightly downwardly so as to flow across and through food product  12 . 
     Air duct piece  180  has a box shape that is secured to wall  185  and base  151  by any suitable fasteners, such as screws or bolts. Air duct piece  180  also has a downwardly extending flange  187  that extends partially into air delivery cutout  186  to form an air delivery port  190 , as shown in FIG.  8 . Air duct piece  178  is shaped to fit over blower  145  and is secured to base  151  and to flat portion  183  by any suitable fastener, such as screws or bolts. Air duct piece  178  includes an air intake port shown as one or more air intake vents  179 . The duct work thus formed provides an air flow passageway from intake vents  179 , through blower  145 , lower heater  140  via the space between base  151  and flat portion  183 , upwardly through box shaped duct piece  180  and out via delivery port  190 . 
     Frame  170  also includes a front wall  174  and a back wall  176 . Front wall  174  and back wall  176  are each secured to base  151  and to air duct pieces  178 ,  180  and  182  by suitable fasteners, such as screws or bolts. 
     Holder  120  has a surface  121  that contains a plurality of apertures  122  arranged to diffuse heat emanating from lower heater  140  via flat portion  183  as well as to allow grease, crumbs, salt and the like to drop through. A quantity of fried food product  12 , shown as French fried potatoes in FIG. 7, is disposed on surface  121 . 
     Holder  120  has a peripheral wall  123  extending generally upward from surface  121 . Peripheral wall  123  has a pair of side walls  123 A and  123 B, a front wall  123 C and a back wall  123 D. Side wall  123 A, front wall  123 C and back wall  123 D are inclined or sloped outwardly from perforated surface  121 . Back wall  123 B is substantially vertical. 
     Holder  120  sits in a like shaped, but slightly larger, box  111 . Box  111  has a rim  113 . Peripheral wall  123  has a rim  124  that rests on rim  113  of box  111 . Rim  113  rests on the top of frame  170  formed by front wall  174 , back wall  176  and air duct pieces  178 ,  180  and  182 . As best seen in FIG. 7, box  111  is dimensioned to dispose surface  121  of holder  120  a short distance above flat portion  183 . For example, this distance may be on the order of 1 to 3 inches for French fried potatoes. 
     Side wall  123 B of holder  120  has a slot  126  and box  111  has a slot  127 . When fully assembled as shown in FIGS. 5 and 7, slots  126  and  127  are aligned with one another and with air delivery port  190 . 
     Box  111  may be removable for the purpose of cleaning, particularly if it is used to trap or collect droppings from surface  121  such as grease, crumbs, salt and the like. Alternatively, these droppings could be collected on a separate sheet or in a separate container that is removable for cleaning. Surface  121  may be flat as shown or curved and holder  120  may be any other desired shape. 
     Lower heater  140  may be any suitable heater for applying heat in an upward direction to the underside of surface  121 . Surface  121  transfers this heat for application in an upward direction to fried food product  12  by natural convection. By way of example, heater  140  is shown as an electrical resistance coil. As shown, lower heater  140  serves a dual purpose of heating air and food product  12 . In alternate embodiments of the invention, two separate heaters may be used. One heater would be disposed in the air flow path to heat the air. The other heater would be disposed beneath flat portion  183  to heat food product  12 . 
     Upper heater  130  includes an upright bracket  131  that is mounted to frame  170 . To this end, back wall  176  has a slot  177  in which a sleeve  134  is seated and secured by any suitable fastener, such as screws or bolts. Upright bracket  131  is seated in sleeve  134 . Horizontal extension  132  extends from upright bracket  131  over holder  120  intermediate side walls  123 A and  123 B. Two radiant heater elements  133  are mounted to horizontal extension  132 . Radiant heater elements  133  radiate heat in a downward direction to fried food  12  as shown by dashed arrows  114  in FIG.  7 . It will be apparent to those skilled in the art that more or less radiant elements may be used. 
     Referring to FIGS. 5 through 7, blower  145  draws ambient air through air vents  179  and accelerates the air through a passageway defined by base  151  and air duct pieces  180  and  182  to air delivery port  190 , as shown by the arrows  154  in FIG.  7 . This passageway is along the spacing formed between base  151  and flat portion  183  and box shaped duct  180 . Baffle  188  directs air flow in a direction generally transverse to the upward and downward directions of heat provided by upper and lower heaters  130  and  140 . This direction is through food product  12  as shown by arrows  159  and across fried food product  12  as shown by arrows  160 . 
     The air flow deflected through fried food product serves to evaporate moisture that forms on the fried food surface as well as to provide additional heating. The air flow deflected over and across fried food product  12  serves to remove any water vapor formed by evaporation from the region above fried food product  12 . The water vapor either is forced away from the region above fried food product  12  or is swept by the air flow into ambient air. This is aided by the sloped surface of side wall  123 A that deflects the air flow upwardly as shown by arrows  162  in FIG.  7 . 
     The combined heat from upper heater  130 , lower heater  140  and the heated air flow operates to extend the time that fried food product  12  is warm enough to be served to customers. The forced hot air flow additionally operates to remove moisture from the surface of fried food  12 , thereby maintaining the surface crispy. The air flow further acts to remove water vapor formed in the region above fried food product  12 . 
     The method according to the present invention involves applying heat in both a downward direction (from upper heater  30 ,  130 ) and in an upward direction (from lower heater  40 ,  140 ) to fried food product  12 . A hot air flow is directed (from hot air delivery port  56 ,  190 ) through and across fried food product  12  in a direction generally transverse to the upward and downward directions. The hot air flow operates to evaporate surface moisture from fried food product  12  and to remove water vapor from a region above fried food product  12 . 
     In the embodiment of FIGS. 1 through 4, the hot air flow is recirculated. In the embodiment of FIGS. 5 through 8, the hot air is developed from a fresh supply of ambient air and is deflected to ambient after passing across or through fried food product  12 . 
     The present invention having been thus described with particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the appended claims.