Spiral chiller apparatus and method of chilling

Abstract

A spiral chiller and a method of chilling a food product in a spiral chiller using a cooling medium wherein (a) the food product is conveyed within the chiller by a spiral conveyor having a plurality of spiral flutes and (b) the cooling medium is discharged either upwardly and/or downwardly within, and/or laterally into, one or more vertical gaps between adjacent pairs of spiral flutes using one or more delivery duct structures which extend inside the interior of the product chilling chamber.

Claims

1. A method of chilling a food product within a product chilling chamber of a spiral chiller, the method comprising the steps of: discharging a cooling medium in a downward direction, in an upward direction, or in both the downward and upward directions from a first plurality of spaced-apart discharge openings located along a first lateral leg of a first conduit, the first lateral leg of the first conduit extending into a vertical gap defined by two adjacent flites of a spiral conveyor and spanning an entire width of the spiral conveyor between a first inner and a first outer edge, an amount of the cooling medium being discharged along the length of the first lateral leg of the first conduit being a greater amount toward the first inner edge of the spiral conveyor than toward the first outer edge; and discharging a cooling medium in a downward direction, in an upward direction, or in both the downward and upward directions from a second plurality of spaced-apart discharge openings located along a second lateral leg of a second conduit, the second conduit being independent of the first conduit, the second lateral leg of the second conduit being at a different vertical elevation than that of the first conduit and extending into a different vertical gap defined by a different two adjacent flutes of the spiral conveyor and spanning an entire width of the spiral conveyor between a second inner and a second outer edge, an amount of the cooling medium being discharged along the length of the second lateral leg of the second conduit being a greater amount toward the second inner edge of the spiral conveyor than toward the second outer edge; wherein the size, horizontal spacing, or size and horizontal spacing of the discharge openings of the first lateral leg and the second lateral leg are arranged so the amount of cooling medium discharged by the plurality of the first spaced-apart discharge openings and by the plurality of the second spaced apart discharge openings located along the first lateral leg and the second lateral leg, respectively, provides a uniform cooling rate across a respective entire width of the spiral conveyor and equalizes a pressure drop of a flow path of cooling medium originating from the first lateral leg of the first conduit with that of the second lateral leg of the second conduit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cutaway elevational view illustrating a prior art spiral chiller 2.

(2) FIG. 2 is a cutaway elevational view illustrating a first embodiment 30 of the inventive spiral chiller.

(3) FIG. 3 is a cutaway elevational view illustrating a second embodiment 100 of the inventive spiral chiller.

(4) FIG. 4 is a cutaway elevational view illustrating a third embodiment 150 of the inventive spiral chiller.

(5) FIG. 5 is cutaway elevational view illustrating a fourth embodiment 170 of the inventive spiral chiller.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) An embodiment 30 of the improved spiral chiller provided by the present invention is illustrated in FIG. 2. As with the prior art chiller 2, the inventive spiral chiller 30 comprises: a product chilling chamber 32 having an interior chamber ceiling 34 and interior side walls 35; a spiral conveyor 36 within the interior of the product chilling chamber 32 below the ceiling 34; a vertical cooling medium return flow path 38 surrounded by the spiral conveyor 36; and a circulation fan 40 located above the spiral conveyor 36 for drawing the cooling medium upwardly through the return flow path 38 and delivering the cooling medium through any desired type of cooling or refrigerating element or system 37 in the upper chamber 42 and then into the product chilling chamber 32.

(7) Although the housing 39 of the inventive chiller 30 includes both a product chilling chamber 32 and an upper chamber 42, it will be understood that the term “product chilling chamber,” as used herein and in the claims, refers to the area of the chiller wherein the spiral conveyor 36 is located and the product is chilled and may refer to the entire chiller housing 39 or to a portion thereof.

(8) The spiral conveyor 36 comprises: an upper end 44 which enters or leaves an upper opening 46 in the chiller housing and is located at an upper end elevation 48; a lower end 50 which enters or leaves a lower opening 52 through the chiller housing and is located at a lower end elevation 54; a series of spiral flites (360° revolutions) 55; a number of vertical gaps 62 such that a vertical gap 62 is provided between each adjacent pair of flites 55; and a longitudinal axis of spiral travel 64. The series of spiral flites 55 includes: an uppermost spiral flite 56; a lowermost spiral flite 58; and at least one, typically a plurality, of intermediate spiral flites 60 between the lowermost flite 58 and the uppermost flite 56. The series of 360° spiral conveyor flites 55 surround and thereby define the vertical cooling medium return flow path 38.

(9) In contrast to the prior art chiller 2, the cooling medium is not circulated in the product chilling chamber 32 of the inventive chiller 30 simply by delivering the cooling medium vertically downward into the chamber 32 through one or more holes or short cones in the chamber ceiling 34. Rather, at least some, and preferably all, of the cooling medium is discharged into the interior of the product chilling chamber 32 by one or a plurality of delivery duct structures 66 which extend downwardly inside the interior of the chamber 32. The interior delivery duct structures 66 each receive a stream 68 of the cold cooling medium from the upper chamber 42 and discharge the cooling medium stream 68 at one or a plurality of locations within the product chilling chamber 32 below the upper end elevation 48 of the spiral conveyor 36.

(10) The discharge openings 70 of the delivery duct structures 66 can be apertures, nozzle openings, slots, or any other type of opening effective for providing the amount, location, pattern, and upward, downward, or intermediate angle of flow desired. The opening(s) 70 will preferably extend below the upper end elevation 48 of the spiral conveyor 36. The opening(s) 70 will more preferably be elevationally located such that they extend downwardly in the product chilling chamber 32 at least to a lateral plane (i.e., a plane perpendicular to the axis of the spiral travel 64) which is at least 25%, 30%, 50%, or 65%, and most preferably at least 90%, of the distance downward from the upper end elevation 48 to the lower end elevation 54. In addition, the delivery ducts 66 and the opening(s) 70 provided therein can be identical or can be of differing lengths, configurations, arrangements, or sizes.

(11) In the embodiment 30 shown in FIG. 2, the cooling medium delivery duct structures 66 each comprise an elongate vertical conduit 72 which is located outside of the spiral conveyor 36 and includes a vertical series of nozzles 70. The series of nozzles 70 extends along substantially the entire height of the spiral conveyor 36 from the upper end elevation 48 to the lower end elevation 54 and the nozzles 70 are directed for distributing and discharging the cooling medium stream 68 laterally inward toward the axis of spiral travel 64 (preferably at a lateral angle substantially perpendicular to the spiral axis 64 as illustrated by arrows 74) through the vertical gaps 62 and across the spiral flites 55.

(12) The distribution of the cooling medium throughout the product chilling chamber 32 and the uniformity of flow and temperature therein can be further enhanced by deploying a plurality of delivery duct structures 66 around the outside of the spiral conveyor 36 at selected intervals. Further, the configuration of the ducts 66, as well as the size, nature, and spacing of the apertures, nozzles, or other discharge openings 70 of the delivery duct structures 66 can be varied as desired to promote more uniform flow throughout the product chilling chamber 32 and to ensure that an excessive amount of the cooling medium does not simply follow a short circuit path across the top of the product chilling chamber 32 to the circulation fan 40.

(13) For example, in order to equalize the pressure drop experienced by the cooling medium following the short circuit path in the upper portion of the product chilling chamber 32 with that experienced by the cooling medium following the longer flow path through the bottom of the chamber 32, the size of the duct discharge openings 70 can be increased toward the bottom of the delivery duct 66. In this arrangement, an opening 75 located at the bottom end of the delivery duct 66 will be larger than an opening 71 nearest the top end and an opening 73 in the intermediate portion of the delivery duct 66 will also be larger than the upper end opening 71 but will be smaller than the lower end opening 75. Alternatively, or in addition, the spacing of the discharge openings 70 can be reduced toward the lower end of the delivery duct 66 such that more openings are provided per linear foot at the lower end of the duct 66 than nearest the upper end.

(14) It will also be understood that, although the delivery ducts 66 of the inventive chiller 30 are positioned outside of the spiral conveyor 36, the flow pattern within the inventive chiller 30 could be reversed or otherwise changed such that the delivery duct(s) 66 extend downwardly inside the spiral flites 55 and discharge the cooling medium outwardly.

(15) A second embodiment 100 of the inventive improved spiral chiller is illustrated in FIG. 3. The spiral chiller 100 is identical to the spiral chiller 30 except for the configuration and operation of the one or more inventive cooling medium delivery duct structures 102 provided inside the interior of the product chilling chamber 105. Each delivery duct structure 102 employed in spiral chiller 100 includes: (a) a vertical leg 104 which extends downwardly from the cooking chamber ceiling 106 and receives a cold cooling medium stream 108 followed by (b) a lateral leg or other element 110 which extends into and discharges the cooling medium within one of the vertical gaps 112 provided between an adjacent pair of spiral flites 114. If more than one delivery duct structure 102 is employed, the lateral elements 110 of the various delivery duct structures 102 can extend into and discharge the cooling medium within the same vertical gap 112 or within other vertical gaps 112 provided between other adjacent pairs of spiral flites 114.

(16) The delivery duct structures 102 employed in the inventive spiral chiller 100 are well suited for providing impingement chilling within the chiller. As illustrated in FIG. 3, the lateral element 110 of each delivery duct 102 will preferably have one or more apertures, nozzles, slots, or other openings 118 in the bottom thereof effective for discharging the cooling medium stream 108 downwardly onto the food product as it is being conveyed on the lower one of the adjacent pair of spiral flites 114. The lateral element 110 of the duct 102 will most preferably include a series of lower openings 118 which provide a uniform distribution of the cooling medium stream 108 across the entire width of the conveyor flite 116.

(17) Alternatively, or in addition, one or more upper openings 120 can be provided in the same or different manner along the top of the lateral element 110 of the duct structure 102 for discharging at least a portion of the cooling medium stream 108 upwardly through the upper one of the adjacent pair of flites 114, assuming that a wire mesh or other open belt spiral conveyor 122 is used, onto the bottom of the food product as it is conveyed over the upper flite 114. The upper opening(s) 120 will also preferably provide uniform distribution of the cooling medium beneath the entire width of the upper conveyor flite 114.

(18) The impingement velocity and the pattern provided in the inventive spiral chiller 100 can be varied as desired by adjusting the fan speed or by changing the number, size, shape, pattern, etc., of the lower and/or upper apertures, slots, nozzles, or other openings 118 and/or 120.

(19) A third embodiment 150 of the inventive spiral chiller is illustrated in FIG. 4. The inventive chiller 150 is identical to the inventive chiller 100 shown in FIG. 3 except that, rather than having only a single discharge element which extends between only one adjacent pair of spiral flites 158, the one or more delivery duct structures 152 of the inventive chiller 150 include multiple discharge legs or other elements 154 which extend into the vertical gaps 156 between at least two adjacent pairs, and most preferably between all adjacent pairs, of the spiral flites 158. Each of the discharge elements 154 illustrated in FIG. 4 is a lateral leg which is identical to the lateral leg 110 of the delivery duct structure 102 shown in FIG. 3 which extends from a vertical leg 152. The lateral discharge elements 154 are preferably effective for distributing the cooling medium across the entire width of the belt and for delivering the cooling medium either downwardly, upwardly, or both downwardly and upwardly in the vertical gaps 156.

(20) Although the discharge elements 110 and 154 shown in FIGS. 3 and 4 comprise lateral pipe segments, it will be understood that the discharge elements 110 and 154 used in inventive chiller 100 and 150 can be of any desired type, shape, or discharge configuration effective for being received between a pair of adjacent spiral flites and for distributing the cooling medium stream over any desired area of the spiral conveyor belt and in any desired pattern.

(21) The product chilling chamber interior portion of a fourth embodiment 170 of the inventive improved spiral chiller is illustrated in FIG. 5. The inventive spiral chiller 170 is identical to the inventive spiral chiller 150 shown in FIG. 4 except that the inventive chiller 170 shown in FIG. 5 utilizes a unique and novel double belt arrangement. The double belt arrangement employed in inventive spiral chiller 170 is particularly well suited for the impingement and improved lateral flow operations provided by the present invention but is also well suited for use in other applications wherein, due for example to the nature of the food product and the cooling medium flow conditions within the spiral chiller, the food product is subject to movement and displacement on the spiral belt during the chilling operation.

(22) The inventive spiral chiller 170 comprises both a first spiral conveyor 172 which runs through the product chilling chamber 174 and a second spiral conveyor 176 which travels within the product chilling chamber 174 above and in unison with the first conveyor 172. During operation, the food product is received and carried through the product chilling chamber 174 between the lower spiral belt 172 and the upper spiral belt 176. The spacing between the lower belt 172 and the upper belt 176 can be selected to correspond with the size and shape of the food product so that the upper belt 176 is effective for holding the food product in place on the lower belt 172. Also in accordance with the present invention, the upper spiral conveyor 176 and the lower spiral conveyor 172 will preferably each comprise a wire mesh or other open spiral belt which will allow the desired convective or impingement flow of the cooling medium through the upper belt 176 and/or the lower belt 172 onto the top and/or bottom surfaces of the food product.

(23) Thus, the present invention is well adapted to carry out the objectives and attain the ends and advantages mentioned above as well as those inherent therein. While presently preferred embodiments have been described for purposes of this disclosure, numerous changes and modifications will be apparent to those of ordinary skill in the art. Such changes and modifications are encompassed within the invention as defined by the claims.