CROSS FLOW TUNNEL FREEZER SYSTEM
A system processes a food product with a cooling gas and includes a housing with a chamber; a blower in communication with the chamber for circulating the cooling gas; a baffle disposed in the chamber for dividing the chamber into a first region for exposing the food product to the cooling gas and a second region in which the cooling gas is moved by the blower for recirculation to the first region of the chamber; an arcuate member disposed in the chamber in spaced relationship with the baffle for providing a flow path between the first and second regions, the arcuate member coacting with the baffle to guide the cooling gas into the flow path; and conveyor means disposed for movement through at least one of the first and second regions for supporting and delivering the food product through the cooling gas.
Conventional tunnel freezers utilize axial flow fans mounted above the product to generate gas flow which impinges the surface of the product and promotes heat transfer. Local velocities from these fans are high, in the range of 2000 feet per minute (fpm). However, there are significant gaps between fans and therefore, large areas are not covered with a uniform high velocity flow. As a result, the total heat transfer coefficient for these processes is low. In addition, these freezers require sufficient height to allow gas to enter from above the axial fan, then be pressurized and distributed onto the product perpendicular to the surface of the product.
Impingement heat transfer is a means of applying airflow for freezing which is very effective at achieving high heat transfer coefficients. With impingement freezing, nearly 85% of the total freezer area can achieve high velocity airflow. However, the gas flow distribution system for impingement freezing is very complicated, as gas must be pressurized, forced through an impingement plate (having 5% open area), fed into specially designed return channels and then brought back into the fans to be recirculated. These systems are costly to build, complex, difficult to clean and to maintain the proper openings of the impingement plates during operation as they tend to clog with cryogenic freezing snow and ice. To unclog and remove the snow and ice, a plate vibration assembly must be installed, which adds cost and complexity to the system.
SUMMARY OF THE INVENTIONOne embodiment of the invention provides an apparatus for processing a food product with a cooling gas, comprising a housing; a chamber disposed in the housing; a blower in communication with the chamber for circulating the cooling gas in the chamber; a baffle disposed in the chamber for dividing the chamber into a first region of the chamber for exposing the food product to the cooling gas and a second region of the chamber in which the cooling gas is moved by the blower for recirculation to the first region of the chamber; an arcuate member disposed in the chamber in spaced relationship with the baffle for providing a flow path between the first and second regions, the arcuate member coacting with the baffle to guide the cooling gas into the flow path; and conveyor means disposed for movement through at least one of the first and second regions for supporting and delivering the food product through the cooling gas.
Another embodiment of the invention provides a method of applying a cooling gas to a food product, comprising conveying a food product along a first path to be cooled in a chamber for cooling; circulating a cooling gas in the cooling chamber along a second path perpendicular to an entire length of the first path; and exposing the food product to the cooling gas moving along the second path for an entire length of the first path in the cooling chamber.
For a more complete understanding of the embodiments of the invention, reference may be had to the following drawings taking in conjunction with the description of the invention, of which:
The embodiments of
The gas flow assembly in the embodiments provides a significant amount of space savings above the product.
As a result, the embodiments of
The embodiments have a much smaller footprint, are compact and extremely easy to clean. It is estimated that the cross flow tunnel freezer embodiments will realize at least a 50% cost savings over a comparable production rate impingement freezing system.
Benefits of the embodiments herein of
a) Heat transfer coefficients achieved in the cross flow airflow configuration at velocities in the range of 2000 ft/min (610 m/min) are comparable to those achieved in a full scale impingement freezer. These higher heat transfer coefficients are achieved with reduced power consumption over current technologies.
b) The cross flow tunnel freezer embodiments have simplicity in construction and reduced capital equipment costs. Overall height will be minimal, compared to conventional tunnel and impingement freezers. The embodiments also provide sanitation benefits, i.e. easier to clean and to maintain the cleanliness.
c) The airflow lends itself to crust freezing applications, such as for example crusting of meat logs (see
Referring to the FIGS.,
An airflow baffle 20 is disposed in the chamber 14 to extend over in spaced relationship from and be in registration with an entire length of each one of the conveyor belts in the chamber 14 to provide a first region “X” for chilling the air, and a second region “Y” wherein the chilled air freezes food products as shown in the
Thereafter, the cryogen gas airflow 23 is directed along an interior arcuate sidewall surface 24 to the second region Y for providing the cryogen airflow 23 to the food products 18. The airflow 23 contacts all surfaces of the food product 18 due to the open mesh conveyor belt 16. The cryogen airflow is exposed to an entire length of the conveyor belt(s) which extends along the chamber 14 of the housing 12. Thereafter, the cryogen airflow 23 is returned to an inlet 26 of a blower 28 and recycled for subsequent chilling by the cryogen nozzles 22 in the region X. The airflow baffle 20 may be constructed and arranged in the chamber 14 such that a proximal end of the baffle 20 is positioned at the blower 28, while a distal end of the baffle extends in the chamber 14 toward the sidewall or arcuate member 24. The airflow 23 is provided along a direction transverse or perpendicular to the direction of movement of the food product 18 on the conveyor belt 16.
The freezer apparatus 10 includes the novel arrangement of the airflow baffle 20 to segregate the freezer chamber 14 into a “cryogen charging” region X for the airflow 23, and a chilling region Y for freezing food product with the airflow 23, such that the cryogen airflow sweeps across an entire length of the belt 16 in the chamber 14 and the product 18 transverse to movement of the product disposed on the belt 16.
The airflow baffle 20 is adjustable with respect to its position in the chamber 14 to accommodate a height of the food product 18 on the conveyor belt 16, and so airflow 23 efficiency can be maximized for each of the product 18. The overall height of the housing 12 may be no greater than 508 mm (or approximately 17-20 inches), excluding a height of any exhaust stacks (not shown). Parasitic heat loads will be minimized and overall system pressure drop will be less than that of a conventional impingement freezer.
The housing 12 may be used as a “module”, whereby a plurality of the modules may be removably attached to each other to provide a crust freezing line.
Other exemplary embodiments of a freezer constructed in accordance with the invention are illustrated in
The housing 12,112 of the freezer apparatus 10,110 may be provided with one or a plurality of doors 30,130 as shown in
Owing to the perspective of
Embodiments in
Referring to
Disposed between the airflow baffle 220 and the secondary air guide baffle 21 is a conveyor belt 216 for transporting product 218 in the apparatus 210. Another conveyor belt 15 is disposed closer to the bottom 25 of the chamber 214, the belt 15 being disposed beneath the secondary air guide baffle 21. Alternatively, the belts 15 and 216 are the same, as
Airflow 223 of the embodiment of
The lower conveyor belt 15 is actually a return portion of the conveyor belt 216, i.e. owing to the perspective of the drawing figure, the conveyor belt 216 is transporting the product 218 into or out of the Figure and so what we are viewing is the product 218 being conveyed by the conveyor 216 through the region X after which the product 218 is removed from the freezer apparatus 210 and the conveyor belt is functioning as a continuous loop so that we see the bottom portion 15 of the conveyor belt 216 returning to accept another load of the product 218.
In the embodiment of
Referring to
It will be understood that the embodiments described herein are merely exemplary and that a person skilled in the art may make many variations and modifications without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope of the invention as described and claimed herein. It should be understood that the embodiments described above are not only in the alternative, but may be combined.
Claims
1. An apparatus for processing a food product with a cooling gas, comprising:
- a housing;
- a chamber disposed in the housing;
- a blower in communication with the chamber for circulating the cooling gas in the chamber;
- a baffle disposed in the chamber for dividing the chamber into a first region of the chamber for exposing the food product to the cooling gas and a second region of the chamber in which the cooling gas is moved by the blower for recirculation to the first region of the chamber;
- an arcuate member disposed in the chamber in spaced relationship with the baffle for providing a flow path between the first and second regions, the arcuate member coacting with the baffle to guide the cooling gas into the flow path; and
- conveyor means disposed for movement through at least one of the first and second regions for supporting and delivering the food product through the cooling gas.
2. The apparatus according to claim 1, wherein the arcuate member comprises an interior surface in the chamber of the housing.
3. The apparatus according to claim 2, wherein the interior surface comprises a curved portion of a sidewall of the housing, the curved portion proximate the flow path.
4. The apparatus according to claim 1, wherein the arcuate member comprises a longitudinal member extending from an area of the first region into the second region, the longitudinal member including a curved portion proximate the flow path.
5. The apparatus according to claim 1, wherein the baffle is constructed of nonporous material.
6. The apparatus according to claim 4, wherein the longitudinal member is constructed of nonporous material.
7. The apparatus according to claim 1, further comprising a cryogen charging assembly in communication with at least one of the first and second regions of the chamber for providing cryogen fluid to the cooling gas.
8. The apparatus according to claim 7, wherein the cryogen charging assembly comprises at least one nozzle disposed in the chamber.
9. The apparatus according to claim 7, wherein the cryogen fluid is selected from cold gas, carbon dioxide, nitrogen and mixtures thereof.
10. The apparatus according to claim 3, wherein the sidewall comprises a door for the housing.
11. The apparatus according to claim 1, wherein the housing further comprises a floor disposed in the chamber, the floor constructed on a grade off the horizontal and tilted downward within the chamber toward the arcuate member.
12. The apparatus according to claim 1, wherein the first region and the flow path extend across an entire surface of the conveyor means upon which the food product is supported, for guiding the cooling gas in a direction across the food product perpendicular to movement of the food product in the chamber.
13. The apparatus according to claim 1, wherein the baffle is disposed in the chamber having a proximate end positioned at the blower and a distal end extending in the chamber toward the arcuate member.
14. The apparatus according to claim 1, wherein the baffle is adapted for movement within the chamber to accommodate height of the food product on the conveyor means in the chamber.
15. The apparatus according to claim 1, wherein the blower is disposed in the chamber.
16. A method of applying a cooling gas to a food product, comprising:
- conveying a food product along a first path to be cooled in a chamber for cooling;
- circulating a cooling gas in the cooling chamber along a second path perpendicular to an entire length of the first path; and
- exposing the food product to the cooling gas moving along the second path for an entire length of the first path in the cooling chamber.
17. The method according to claim 16, further comprising charging the cooling gas with a cryogenic fluid at a select location in the cooling chamber during the circulating of the cooling gas.
18. The method according to claim 17, wherein the cryogenic fluid is selected from cold gas, carbon dioxide, nitrogen and combination thereof.
19. The method according to claim 16, further comprising dividing the cooling chamber into a first region wherein the food product is conveyed along the first path for exposure to the cooling gas circulating along a second path, and a second region wherein the cooling gas is recirculated in the chamber.
20. The method according to claim 19, further comprising adjusting a height of the first region to accommodate a height of the food product.
Type: Application
Filed: Nov 25, 2008
Publication Date: Dec 23, 2010
Inventor: Michael D. Newman (Hillsborough, NJ)
Application Number: 12/743,257
International Classification: F25D 13/06 (20060101); F25D 25/04 (20060101); F25D 17/06 (20060101);