Patent Publication Number: US-2015068223-A1

Title: Rainfall chiller

Description:
RELATED APPLICATIONS 
     The present invention claims priority to U.S. Provisional Patent Application No. 61/875,177, entitled Rainfall Chiller, filed Sep. 9, 2013, the contents of which are herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates generally to cooling systems for items on a conveyor. More particularly, the invention relates to a counterflow rainfall chilling system for cooling items on a conveyor or other moving substrate or transporter. 
     Chillers have been used to reduce the temperature of products. Examples of products that may require chilling include hot cooked foods, such as vegetables, shrimp and other animals, and other known products. Rainfall chillers operate by spraying coolant, such as water or another fluid, over items conveyed beneath the spray to reduce the temperature of the items through heat transfer with the incoming coolant. The temperature and/or volume of the incoming coolant may be controlled to control the cooling process. 
     SUMMARY OF THE INVENTION 
     A counterflow chilling system employs a series of recirculating cooling modules for cooling product passing through the series on a conveyor. A recirculating cooling module comprises a reservoir for collecting coolant below the conveyor, a pump for pumping coolant from the reservoir, a sprayer for spraying pumped coolant over the product and a spillover opening for passing overflow coolant from the reservoir into an adjacent recirculating cooling module or a system outlet. The chilling system forms a series of recirculating zones operating at increasing equilibrium temperatures. 
     According to one aspect, a chilling system for chilling products comprises a conveyor for conveying a product and a plurality of recirculation modules. Each recirculation module comprises a reservoir below the conveyor, a pump for pumping coolant from the reservoir, a pan for spraying pumped coolant over the product on the conveyor, and an outlet passageway in the reservoir for passing coolant into an adjacent reservoir or an outlet of the chilling system. 
     According to another aspect of the invention, recirculating module for a chiller comprises a reservoir having an inlet opening and a spillover opening, an inlet for a conveyor above the spillover opening, an outlet for the conveyor above the spillover opening, a pump having a pump inlet in communication with the reservoir and a pump outlet. The module also includes a sprayer in communication with the pump outlet for spraying pumped coolant over items on the conveyor. 
     According to another aspect, a method of changing the temperature of a product on a conveyor comprises the steps of conveying a product through a chiller, spraying coolant over the product in a first zone using a first sprayer, collecting sprayed coolant in the first zone, pumping sprayed coolant in the first zone back to the first sprayer, passing overflow coolant from the first zone into a second zone and spraying coolant over the product in the second zone using a second sprayer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These features and aspects of the invention, as well as its advantages, are better understood by referring to the following description, appended claims, and accompanying drawings, in which: 
         FIG. 1  is a front view of a chilling system according to an illustrative embodiment of the invention; 
         FIG. 2  is a front view of a single module of the chilling system of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the module of  FIG. 2  through lines A-A; 
         FIG. 4  is a front view of the module of  FIG. 2  in a cleaning mode; and 
         FIG. 5  is a cross-sectional view of the module of  FIG. 4  in the cleaning mode through lines B-B. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A counterflow rainfall chilling system employs recirculating modules that spill coolant into a subsequent module. The invention will be described below relative to an illustrative embodiment. Those skilled in the art will recognize that the invention is not limited to the illustrative embodiment. 
       FIG. 1  is a front view of an embodiment of a chilling system  10 . The chilling system is used to reduce or otherwise modify the temperature of items conveyed on a conveyor, illustrated as a conveyor belt  20 , or other moving substrate. The illustrative conveyor comprises a conveyor belt  20  trained around sprockets  21 , though any suitable means for conveying products through the chilling system may be used. 
     The chilling system comprises a series of modules  100   a - 100   d  arranged side-by-side and in fluid communication with each other. Each module recirculates a coolant, such as water, over the product. The illustrative chilling system consists of four modules in series, but the invention may comprise any suitable number of modules. 
     The chiller  10  includes a coolant inlet  13  for inputting a coolant, such as cold water, into the system. Each module corresponds to and creates a temperature zone in a selected section of the conveyor to modify the temperature of the product. The temperature zone of the first module  100   a  is the coldest and the temperature zone of the last module  100   d  is the warmest. The spent coolant exits the chiller at an outlet  15 . The spent coolant may be recycled, recirculated or discharged. 
     In the illustrative embodiment, hot product enters the chiller at the first end  11  and cool product exits the chiller at the second end  12 . The change in temperature in the product occurs in stages. The chilling system transports hot products upstream in a flow path towards incoming chilled coolant, so that hotter products are partly cooled by the warmer part of the coolant heated by products being cooled, and are transported towards the cooler coolant source  13  as they become cooler. The conveyor belt  20  conveys product at a first, relatively high temperature into a first end  11  of the chiller, and through each of the modules. Each module modifies, preferably reduces, the temperature of the product such that product is conveyed out a second end  12  of the chiller at a second, relatively lower temperature. 
     Each module  100  recirculates coolant and sprays the coolant over the product to effect cooling. From the coolant inlet  13 , coolant passes to an inlet pan  101  in communication with a first module  100   a.  The inlet pan  101  feeds the coolant to a reservoir  110  of the first module, shown in  FIGS. 2 and 3 . The reservoir  110  is below the conveyor  20 . A pump, illustrated as an axial pump  120 , pulls coolant from the reservoir  110  and passes the coolant to a flow distribution pan  140 , which feeds the coolant to spray pans  150  above the conveyor belt  20 . The spray pans  150  rain the coolant onto the product to cool, or otherwise change the temperature of, the product. The conveyor  20  is foraminous or otherwise configured to allow the passage of coolant therethrough, so that the spent coolant passes back into the reservoir  110  for recirculation. 
     In the illustrative embodiment, each module includes four adjacent spray pans  150 , various suitable embodiments of which are known in the art. The spray pan  150  is removably coupled to the frame for each module  100 . The spray pan  150  includes an array of openings for creating a rainfall-like spray over the product. In the illustrative embodiment, each spray pan  150  spans the width of the conveyor belt  20 . The frame of each module includes means for locking the spray pan into place. As shown in  FIGS. 4 and 5 , each pan  150  can lock in an up position for cleaning. A latch  155  may be used to lock the pan  150  in an operating position during operation. 
     The illustrative axial pump  120  includes an inlet  121 , an outlet  122 , housing  130 , motor  124 , a shaft  125  and propeller  126  driven by the motor  124 . The housing  130  includes a removable shroud  131 , as shown in  FIG. 3 . The shroud may be removed to access the propellers for cleaning, as shown in  FIG. 5 , by twisting the shroud to unlock it and pulling it off. The flange  132  of the shroud enables twisting. A door  102  to the reservoir  110  of the module may open to allow access to the propeller  126 . 
     The illustrative housing of the axial pump further includes a flow straightener  132  and a deflector  134 , though the invention is not so limited. The deflector automatically moves into position when coolant flows through the pump to serve as a velocity break for the coolant flow, ensuring that the pans fill evenly. The illustrative deflector  134  automatically moves down, as shown in  FIG. 5 , when there is no flow through the pump to allow for cleaning. 
     The flow distribution pan  140  receives the pumped coolant from the pump outlet  122  and distributes the coolant among the spray pans  150 . The spray pans rain coolant over the passing product on the conveyor belt  20 . The coolant then passes into the reservoir  110 , where it is recirculated by the axial pump  120 . The module continues to recirculate coolant over the product, reaching an equilibrium temperature. 
     The illustrative axial pump  120  has a relatively high flow rate, between about 150 and about 200 gallons per minute to create well-mixed coolant. In one embodiment, the flow rate is about twice the volume of the reservoir  110  to ensure well-mixed coolant in each zone. 
     The illustrative chilling system  10  allows coolant to flow naturally between temperature zones formed by modules in communication with each other. The outlet  122  of each pump returns coolant to the zone  110  from which the coolant was drawn to create an independent recirculation loop, while allowing some sharing of coolant between the zones via a communication means. For example, in an illustrative embodiment, the reservoir  110  of the first module  100   a  includes a passage  170  for allowing overflow coolant from the first reservoir to pass into the reservoir of the adjacent downstream module  100   b.  The passage is preferably below the conveyor belt  20 . The coolant that spills into the downstream reservoir  110   b  is generally warmer than the input coolant, due to heat exchange within the recirculating module of the coolant and the product on the conveyor belt  20 . 
     The warmer coolant spills into the second reservoir via an input passage  171 , and the second module  100   b  recirculates the coolant using an axial pump, as described above, to create a temperature zone that is at a higher equilibrium temperature than the first module  100   a.  The reservoir of the second module  100   b  spills overflow coolant into the third module  100   c  via an outlet passage or other communication means. The third module  100   c  recirculates the coolant within a third zone around the conveyor belt  20  to create a third temperature zone having an equilibrium temperature that is higher than the second module equilibrium temperature. The third module spills coolant into a fourth module  100   d,  which recirculates the coolant within a fourth zone at a higher equilibrium temperature. The outlet passage of the fourth module reservoir passes spent coolant into the outlet  15 . 
     Preferably, each module  100  forms an independent recirculation zone, with a communication means, which can be a valve, passageway, opening, funnel or other suitable means, between the zones formed below the conveyor belt. 
     The flow of coolant over the product is independent of the input coolant, allowing a high level of coolant to spray over the product without increasing the amount of input coolant. 
     In one embodiment of the invention, the input coolant has a temperature of between about 30° and about 45° F. and the discharge coolant is between about 65° and about 80° F., though the invention is not so limited. 
     Although the invention has been described in detail with reference to a few exemplary versions, other versions are possible. The scope of the claims is not meant to be limited to the versions described in detail.