CROSSFLOW SPIRAL HEAT TRANSFER SYSTEM WITH SELF-STACKING SPIRAL CONVEYOR BELT
A refrigeration system includes a housing having a top, a bottom, first and second opposed sides, and containing an atmosphere; a conveyor apparatus including a self-stacking, self-supported, spiral conveyor belt and a drive mechanism, wherein the conveyor belt includes a plurality of tiers and is at least partially disposed within the housing such that the conveyor belt can travel within the housing from the bottom towards the top of the housing or from the top towards the bottom of the housing; and an atmosphere circulation apparatus having at least one blower in communication with the atmosphere for circulating at least a portion of the atmosphere within the housing from proximate the first opposed side to the second opposed side and back towards the first opposed side, wherein the portion of the atmosphere circulated passes over the conveyor belt in a crossflow manner at least once.
This application is a continuation-in-part of U.S. Ser. No. 12/184,386, filed on Aug. 1, 2008, which claims the benefit of the filing date, under 35 U.S.C. §119(e), of U.S. Provisional Patent Application Ser. No. 60/964,458, filed on Aug. 13, 2007.
The present disclosure relates to a heat transfer system for cooling, chilling or otherwise removing heat from, or warming, heating or otherwise supplying heat to products, such as for example food products.
In certain illustrative refrigeration systems, a line of products to be refrigerated is moved through the refrigeration system, along a spiral or helical pathway through the cold or chilling region. Systems in which products to be refrigerated follow a spiral or helical pathway through the cold region are conventionally termed spiral refrigeration systems. Related systems may be used to supply heat to products.
One type of refrigeration system used in the industry to remove heat from products is a spiral refrigeration system. Unless otherwise noted, as used herein, “spiral” refers to both spiral and helical forms, as well as any other forms which allow for similar movement of products through the heat transfer system.
A single pass configuration spiral refrigeration system is one in which a gas, such as a cryogen, is directed by at least one blower, such as at least one fan, to flow past the products to be cooled once. The gas is then returned from the products to the at least one blower through return gas conveyances in the system. The return gas conveyances may, in certain embodiments, consist of ductwork which does not contain products from which it is desirable to remove heat.
A double pass configuration spiral refrigeration system is one in which a gas, such as a cryogen, is directed by at least one blower, such as at least one fan, to flow past the products to be cooled twice. The gas is circulated past the products once, then passes over the products a second time as it returns to the at least one blower.
Embodiments of the subject matter are disclosed with reference to the accompanying drawings and are for illustrative purposes only. The subject matter is not limited in its application to the details of construction or the arrangement of the components illustrated in the drawings. Like reference numerals are used to indicate like components, unless otherwise indicated.
Discussion of the heat transfer system embodiments is with respect to cooling and heating a product, and reference to refrigeration systems could similarly include references to a heating system.
Variables defining a spiral pathway include, but are not limited to, diameter, height and pitch. As used herein, a “tier” is the part of a helix corresponding to one full thread of the spiral.
In certain embodiments, the present system can also be used in a manner of heat transfer to also heat or cook products, such as food products. The higher the velocity of the gas being employed to pass over the products, the greater the heat transfer experienced by the products.
In certain embodiments, a drum which moves the spiral conveyor belt cooperates with the spiral belt to create a bifurcated pathway for the gas, which pathway has a width equal to the width of the conveyor belt upon which the products are transported so that heat transfer gases are efficiently used.
In other embodiments, a central drum is not necessary. The spiral conveyor belt is self-stacking, with each tier sitting atop the tier below it. The self-stacking spiral conveyor belt may be driven by a rotating platform on which the bottom tier of the conveyor belt rests, or may be driven by modular drive mechanisms placed along the path of the self-stacking spiral conveyor belt. The self-stacking belt minimizes the height between tiers, and eliminates the necessity for bifurcated gas flow, resulting in efficiencies of size and cooling power consumption.
In the refrigeration system embodiments herein in which heat is transferred from a product to be refrigerated to a flowing refrigeration fluid, one mode of cooling the product to be refrigerated is forced convection. In forced convection, the heat transfer coefficient is a function of the flow velocity of the refrigeration fluid. Heat transfer for cooling objects also includes a factor that the higher the velocity of gas used to effect heat transfer, the greater the heat transfer rate.
Certain refrigeration fluids may be called “cryogens”. As used in refrigeration, cryogen gas may be as cold as −250° F. (−157° C.), or as dictated by the minimum temperature at which the gas exists in its gaseous state.
In certain embodiments, in which the spiral refrigeration system includes a double pass configuration, in addition to the efficiency benefits achieved by reducing disused regions, the size of the freezing system may be made significantly smaller because the refrigeration medium, such as a gas, is returned to the main blowers along the product pathway or in the product processing zone. In these embodiments, dedicated external return chambers and related ductwork are not necessary. This results in a savings in overall system cost. In addition, a lower amount of structural material is required to be cooled down which results in a secondary efficiency improvement.
In certain embodiments, a refrigeration system is provided, which includes: a housing having a top, a bottom, first and second opposed sides, and containing an atmosphere; a conveyor apparatus comprising a self-stacking, self-supported, spiral conveyor belt and a drive mechanism, wherein the conveyor belt includes a plurality of tiers and is at least partially disposed within the housing such that the conveyor belt can travel within the housing from the bottom towards the top of the housing or from the top towards the bottom of the housing; and an atmosphere circulation apparatus having at least one blower in communication with the atmosphere for circulating at least a portion of the atmosphere within the housing from proximate the first opposed side to the second opposed side and back towards the first opposed side, wherein the portion of the atmosphere circulated passes over the conveyor belt in a crossflow manner at least once.
The term “crossflow” is meant to describe the pattern of flow of the circulated atmosphere across and/or through the self-stacking conveyor belt; the circulated atmosphere passes through the refrigeration system substantially parallel to the top and/or bottom of the refrigeration system, and passes along the length of the refrigeration system at substantially similar speeds across the width of the refrigeration system.
The self-stacking, self-supported spiral conveyor belt may be operated in a continual state of movement, either ascending or descending, depending on the production line requirements. The following description refers to an ascending conveyor belt for ease of description, but the description should not be construed as limiting the conveyor belt to ascending movement. As the conveyor belt ascends through the heat transfer system, the sidewall typically engages with a conveyor belt structure above it and/or below it. Thus, the entire conveyor belt is stabilized due to the releasable engagement of the tiers of the conveyor belt. As the conveyor belt passes out of the heat transfer system, the uppermost tier of the belt disengages and lifts away from the tier beneath it, thereby leaving the spiral assembly, and continues to a take-up assembly which compensates for overall conveyor belt slack. The conveyor belt proceeds from the take-up assembly to a return section to be reintroduced into the heat transfer system at the bottom of the spiral assembly.
In certain embodiments, the height between each of the plurality of tiers of the spiral conveyor belt may be from about 3 inches to about 8 inches. In other embodiments, the height between each of the plurality of tiers of the spiral conveyor belt may be from about 3 inches to about 7 inches. In yet other embodiments, the height between each of the plurality of tiers of the spiral conveyor belt may be from about 3 inches to about 6 inches. In further embodiments, the height between each of the plurality of tiers of the spiral conveyor belt may be from about 4 inches to about 4.5 inches. Generally, the height between each tier will depend on the height of the product which is to be transported through the refrigeration system, with consideration being made to adequate gas flow to achieve acceptable heat transfer. A benefit of the present self-stacking conveyor belt is that the height between tiers may be drastically reduced as compared to conventional tiered belt systems traveling on fixed rails, allowing for increased cost-efficiency due to space savings and cooling gas savings.
In certain embodiments, the refrigeration system may comprise a product carrying component of the conveyor belt which is at least partially gas permeable. The product carrying component may comprise a horizontal surface on which products rest, and which convey the products through the refrigeration system.
In certain embodiments, the conveyor belt travels from the bottom of the housing towards the top of the housing, and a return channel is provided proximate to the top of the housing, wherein the conveyor belt is not present within the space of the return channel, such that the at least one blower forces the circulated atmosphere in a crossflow manner over the conveyor belt and the circulated atmosphere circulates back to the at least one blower via the return channel.
In certain embodiments, the conveyor belt travels from the top of the housing towards the bottom of the housing, and a return channel is provided proximate to the bottom of the housing, wherein the conveyor belt is not present within the space of the return channel, such that the at least one blower forces the circulated atmosphere in a crossflow manner over the conveyor belt and the circulated atmosphere circulates back to the at least one blower via the return channel.
In certain embodiments, the refrigeration system may comprise a product carrying component which is substantially gas impermeable.
In certain embodiments, the at least one blower forces the circulated atmosphere over the conveyor belt twice in a single cycle, such that the circulated atmosphere passes over upper tiers of the conveyor belt proximate to the top of the housing as the circulated atmosphere passes from the first opposing side to the second opposing side, and passes over lower tiers of the conveyor belt proximate to the bottom of the housing as the atmosphere passes from the second opposing side to the first opposing side, circulating back towards the at least one blower.
In certain embodiments, the at least one blower forces the circulated atmosphere over the conveyor belt twice in a single cycle, such that the circulated atmosphere passes over lower tiers of the conveyor belt proximate to the bottom of the housing as the circulated atmosphere passes from the first opposing side to the second opposing side, and passes over upper tiers of the conveyor belt proximate to the top of the housing as the atmosphere passes from the second opposing side to the first opposing side, circulating back towards the at least one blower.
In certain embodiments, the driving mechanism may comprise a rotating platform. The rotating platform may be disposed at or within a bottom wall of the housing. Alternatively, the rotating platform may disposed within the housing.
In certain embodiments, the blower may be adapted to inject a cooling agent into the atmosphere within the housing. The cooling agent may be a cryogen, such as at least one of carbon dioxide, nitrogen, or air.
Referring to
The spiral belt 50 provides for a spiral pathway. The spiral pathway includes an upper pathway 52 of the tiers 51 within the upper portion 16; and a lower pathway 54 of the tiers 53 within the lower portion 18. The product is transported upon the tiers 51, 53 of the belt 50. The drum 40 drives the belt 50 along the spiral or helical path.
The baffle 30 separates the upper pathway 52 from the lower pathway 54. The baffle 30 works in conjunction with the drum 40 to create the upper pathway 52 and the lower pathway 54 to each have a width equal to a width of the belt 50. This is because gas flow 25 does not flow through the drum 40, but rather is bifurcated by the drum 40 as shown in
In operation, and referring to
As shown in
In effect, the product is subjected to a double pass flow of the gas 25. The cryogen gas flow 25 is restricted for flow across a width of the tiers 51, 53 of the conveyor belt 50, such that none of the cryogen gas is wasted on heat transfer at unnecessary portions of the freezer system 10.
The construction and operation of the embodiment shown in
In the crossflow spiral refrigeration system 10 of
Thus, the two-pass configuration of the present system 10 may require only about 50% of the conventional airflow used in conventional airflow schemes, such as one-pass flow configurations.
In addition to the operational efficiency benefits achieved by the system 10, the size of the freezing system 10 may be made significantly smaller because the gas is returned to the blowers 20A, 20B through the upper and lower pathways. Separate gas return chambers and ductwork are not necessary, thereby providing for a smaller “footprint” for the system 10. This results in a significant savings in overall system cost.
As shown in
The system 110 shown in
Disposed within the space 114 is a drum 140 about which a spiral conveyor belt 150 is engaged, the belt 150 being driven along the spiral or helical path by the drum 140. The drum 140 is impervious to fluid flow and bifurcates the gas flow 125 similarly to that which occurs with respect to the embodiment of
The internal chamber 114 consists of an upper portion 116 and a lower portion 118. The upper portion 116 and lower portion 118 are segregated from each other by a baffle 130 which extends along the internal chamber 114 of the housing 112. The upper portion 116 of the internal chamber 114 contains the upper pathway 152, while the lower portion 118 of the internal chamber 114 contains the lower pathway 154. The conveyor belt and its tiers 151, 153 move between the upper and lower pathways 152, 154.
Disposed in the upper portion 116 of the internal chamber 114 is a blower or fan 122A, while disposed at the lower portion 118 of the internal chamber 114 is another blower or fan 122B. Fans 122A, 122B may be arranged at different sides of the housing 112, such as at opposed sides of the housing 112. In addition, one of the fans, such as the fan 122A, is disposed in the upper portion 116, while the other blower such as the fan 122B is disposed in the lower portion 118. The baffle 130 surrounds the drum 140 and prevents fluid flow 125 between and among the upper portion 116 and the lower portion 118, except for areas of the baffle 130 shown generally at 131 and 132. The areas 131, 132 are those areas permitting gas flow 125 to occur between the lower portion 118 and the upper portion 116. This can be as a result of the construction of the baffle 130 extending up to only that point in the interior space 114 where the baffle meets the fans 122A, 122B, or apertures (not shown) may be provided in the baffle 130 to enable the gas flow 125 to be drawn from the lower portion into the upper portion via the fan 122A, and from the upper portion 116 into the lower portion 118 via the fan 122B. In either arrangement there is provided the continuous circulatory effect between and among the upper and lower portions 116, 118.
The conveyor belt 150 is arranged to extend between the lower portion 118 and the upper portion 116. At least one and preferably a plurality of the tiers 151 of the belt 150 are disposed at any given time in the upper portion 116. At least one and preferably a plurality of the tiers 153 of the belt 150 are disposed in the lower portion 118 at any given time.
As shown in
Although the perspective of
Conduits 124, 126 are in communication with the blower chambers 120, 170 to “charge” the system 110 with a cooling or heating fluid as necessary. The conduits 124, 126 are connected to a source (not shown) of cooling or heating fluid and may be in communication with other areas of the chamber 114.
The system 110 shown in
In the embodiments of
In the embodiments shown in
A self-stacking, self-supporting spiral conveyor belt 450 is disposed within the product chamber 416, such that the circulating atmosphere 425 passes over products (not shown) disposed on the conveyor belt 450 in order to create a heat transfer relationship between the atmosphere 425 and the products. The conveyor belt 450 rests on a rotating platform 440 which is disposed at the bottom wall of the housing 412. The rotating platform 440 provides the drive force necessary to move the conveyor belt 450 through the system 410. The conveyor belt 450 includes tiers 451 which may be spaced apart from each other according to and to accommodate the product to be processed by the system 410. The self-stacking conveyor belt 450 allows for minimal heights between the tiers 451, which in turn allows for increased efficiency, even in the single-pass arrangement of
A self-stacking, self-supporting spiral conveyor belt 550 is disposed within the product chamber 516, such that the circulating atmosphere 525 passes over products (not shown) disposed on the conveyor belt 550 in order to create a heat transfer relationship between the atmosphere 525 and the products. The conveyor belt 550 rests on a rotating platform 540 have a supporting surface which is disposed for coaction with the baffle 530. The rotating platform 540 provides the drive force necessary to move the conveyor belt 550 through the system 510. The conveyor belt 550 includes tiers 551 which may be spaced apart from each other according to and to accommodate the product to be processed by the system 510. The self-stacking conveyor belt 550 allows for minimal heights between the tiers 551, which in turn allows for increased efficiency, even in the single-pass arrangement of
A self-stacking, self-supporting spiral conveyor belt 650 is disposed within the product chamber 616, such that the circulating atmosphere 625 first passes over products (not shown) disposed on the upper tiers 651 of the conveyor belt 650, then passes through return chamber 660 and passes over products disposed on the lower tiers 653 in order to create a double-pass heat transfer relationship between the atmosphere 625 and the products. The conveyor belt 650 rests on a rotating platform 640 which is disposed at the bottom of the housing 612. The rotating platform 640 provides the drive force necessary to move the conveyor belt 650 through the system 610. The tiers 651, 653 may be spaced apart from each other according to and to accommodate the product to be processed by the system 610. The self-stacking conveyor belt 650 allows for minimal heights between the tiers 651. The double-pass arrangement of
The following examples are set forth merely to further illustrate the subject heat transfer system. The illustrative examples should not be construed as limiting the heat transfer system in any manner.
A double-pass heat transfer system similar to the system described in
A double-pass heat transfer system similar to the system described in
While the present subject matter has been described above in connection with illustrative embodiments, as shown in the various Figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments for performing the same function without deviating therefrom. Further, all embodiments disclosed are not necessarily in the alternative, as various embodiments may be combined to provide the desired characteristics. Variations can be made without departing from the spirit and scope of the invention. Therefore, the crossflow spiral heat transfer system should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the attached claims.
Claims
1. A refrigeration system, comprising:
- a housing having a top, a bottom, first and second opposed sides, and containing an atmosphere;
- a conveyor apparatus comprising a self-stacking, self-supported, spiral conveyor belt and a drive mechanism, wherein the conveyor belt comprises a plurality of tiers and is at least partially disposed within the housing such that the conveyor belt can travel within the housing from the bottom towards the top of the housing or from the top towards the bottom of the housing; and
- an atmosphere circulation apparatus comprising at least one blower in communication with the atmosphere for circulating at least a portion of the atmosphere within the housing from proximate the first opposed side to the second opposed side and back towards the first opposed side, wherein the portion of the atmosphere circulated passes over the conveyor belt in a crossflow manner at least once.
2. The refrigeration system of claim 1, wherein a height between each one of the plurality of tiers is from about 3 inches to about 8 inches.
3. The refrigeration system of claim 1, wherein the conveyor belt comprises a product carrying surface being at least partially gas permeable.
4. The refrigeration system of claim 3, wherein the conveyor belt is constructed and arranged to travel from the bottom towards the top of the housing, and further comprising a return channel disposed proximate the top of the housing, wherein the conveyor belt does not extend within the return channel, such that the at least one blower forces the atmosphere circulated in a crossflow manner over the conveyor belt and through the return channel back to the at least one blower.
5. The refrigeration system of claim 3, wherein the conveyor belt is constructed and arranged to travel from the top towards the bottom of the housing, and further comprising a return channel disposed proximate the bottom of the housing, wherein the conveyor belt does not extend within the return channel, such that the at least one blower forces the atmosphere circulated in a crossflow manner over the conveyor belt and through the return channel back to the at least one blower.
6. The refrigeration system of claim 1, wherein the conveyor belt comprises a product carrying surface being substantially gas impermeable.
7. The refrigeration system of claim 6, wherein the at least one blower forces the atmosphere circulated over the conveyor belt twice in a single cycle, such that the circulated atmosphere passes over upper tiers of the conveyor belt proximate the top of the housing as the circulated atmosphere passes from the first opposed side to the second opposed side, and passes over lower tiers of the conveyor belt proximate the bottom of the housing as the atmosphere passes from the second opposed side to the first opposed side, circulating back towards the at least one blower.
8. The refrigeration system of claim 6, wherein the at least one blower forces the atmosphere circulated over the conveyor belt twice in a single cycle, such that the circulated atmosphere passes over lower tiers of the conveyor belt proximate the bottom of the housing as the atmosphere circulated passes from the first opposed side to the second opposed side, and passes over upper tiers of the conveyor belt proximate the top of the housing as the atmosphere passes from the second opposed side to the first opposed side, circulating back towards the at least one blower.
9. The refrigeration system of claim 1, wherein the drive mechanism comprises a rotating platform.
10. The refrigeration system of claim 9, wherein the rotating platform is disposed at the bottom of the housing.
11. The refrigeration system of claim 9, wherein the rotating platform is disposed within the housing.
12. The refrigeration system of claim 1, wherein the at least one blower is constructed and arranged to provide a cooling substance to the atmosphere within the housing.
13. The refrigeration system of claim 12, wherein the cooling substance comprises a cryogen.
14. The refrigeration system of claim 13, wherein the cryogen comprises at least one of carbon dioxide, nitrogen or air.
15. The refrigeration system of claim 1, wherein the at least one blower is disposed within the housing.
Type: Application
Filed: Oct 13, 2010
Publication Date: Oct 13, 2011
Inventors: Stephen A. McCormick (Warrington, PA), Michael D. Newman (Hillsborough, NJ)
Application Number: 12/903,438
International Classification: F25D 25/04 (20060101);