Method for processing food product

FIELD OF THE INVENTION

0001The present invention relates to rotary blanchers and more particularly to a method and rotary blancher for processing food products that comprises introducing a fluid into the heat transfer medium in the blancher to more efficiently and more uniformly heat the food products in the blancher and which can be used to blanch, cook or pasteurize the food products.

BACKGROUND OF THE INVENTION

0002A wide variety of food products, such as pasta, beans, corn, peas, and other vegetables and fruit, are processed every day around the world by blanching or heating. For many years, the basic rotary blancher consisted of an elongate cylindrical perforate drum received in a tank filled with heated water. Food products are continuously introduced through an inlet in one end of the drum and heated by the water in the tank. During operation, flights of a helical auger in the drum rotate and urge the food products from the drum inlet toward a drum outlet.

0003However, food products tend to clump together as the drum rotates resulting in poor heat transfer and uneven heating, especially for those food products in the middle of the clump. To combat this problem, straight and curved baffles have been employed between adjacent flights of the auger to lift and tumble food product during rotation of the drum to help improve heat transfer and more evenly heat food product. Examples of such baffles are disclosed in Zittel, U.S. Pat. Nos. 5,632,195 and 5,456,091. As a result of this improvement, blanching capacity was not only roughly doubled, but the food products were more uniformly blanched. For example, where nine inches of one specific type of food product could previously be blanched, a blancher equipped with these baffles could more uniformly blanch about eighteen inches of the same food product.

0004In addition to this type of mechanical agitation, other methods have also been employed to improve heat transfer. For example, as is disclosed in Zittel, U.S. Pat. Nos. 5,752,431 and 5,632,195, air and steam have been introduced into the water in the tank to help increase heat transfer efficiency. Air has also been used to improve cooling efficiency in food cooling applications. For example, U.S. Pat. No. 4,875,344 discloses injecting relatively low volumes of low-pressure air, namely warm air into cold water, to improve cooling of food products in a rotary drum chiller. In some food product cooling applications, manifolds connected to nozzles that introduce the air into the chiller have been located between the tank and drum at the five o'clock and seven o'clock positions relative to the drum's center. However, in each of these applications, the air was injected at a pressure of no greater than 150 pounds per square inch (psi) at a flow rate no more than 25 cubic feet per minute (CFM).

0005Directed flows of water have also been used to increase heat transfer. For example, U.S. Pat. No. 5,456,091 discloses improved cooling by directing flows of water from nozzles connected to a manifold toward the drum to agitate food products in the drum. However, a relatively low volume of water of no more than 8 gallons per minute per food of blancher length (gpm/ft) at a pressure no greater than 40 psi was used for these cooling applications. While directed flows of water have also been tried in blanchers to improve heat transfer, it has been done using pressures no greater than 8 psi and flow rates no greater than 10 gpm/ft.

0006It is believed that greater pressures and flow rates of directed water flows have not been tried before because the lower pressures and flow rates previously tried did not increase efficiency so dramatically as to predict a correspondingly greater efficiency increase. Moreover, the cost of bigger and more powerful pumps and other equipment needed to deliver greater flow rates, particularly at higher pressures, was thought to be so cost prohibitive that any possible performance advantage was believed not to be worth it.

0007It has always been very difficult for rotary blanchers to process food products that are relatively heavy, typically having a density greater than 55 pounds per cubic foot (lbs/ft³). Examples of food products that are relatively heavy include packaged meats, such as hot dogs and turkey breasts, as well as other types of food products that are not packaged. While baffles have been used to help turn over and agitate food products during operation, heavier food products tend to clump together on the bottom and along the side of the rotating drum where the drum leaves the water. This is believed to be caused, at least in part, by the increased weight of the food products causing them to sink and by the increased friction between the food products and the rotating drum.

0008Testing has shown that, most, if not virtually all, heavy food products congregate along one side of the drum near the bottom of the drum in a region that occupies less than about 20% of the total volume of the drum dramatically reducing the amount of food product surface area actually exposed directly to the hot water. By congregating in a clump, the food products inside the clump are not heated directly by the water but by other outer food products, which means it takes more time to heat all of the food products to the desired temperature than is acceptable. Other experiments have shown that these lower turbulence (i.e. lower volume and pressure) flows of air and water used in the past, even if the blancher is equipped with agitating baffles, will not break up and agitate heavy food products enough to achieve the desired level of heat transfer needed to make blanching of heavy food products commercially viable.

0009Pasta is a relatively heavy food product that has a density less than 55 lbs/ft³. Pasta, however, is relatively fragile and must be handled much more carefully during blanching than most other types of food products, which has limited attempts in the past to increase heat transfer. Past attempts to increase heat transfer include the use of baffles and the introduce of air having a pressure no greater than 2 psi at a volume no greater than 40 CFM per foot of blancher length. As a result, throughput for a 72-inch diameter blancher has been heretofore limited to about 3500 pounds of pasta per hour, making production undesirably slow.

0010While the food processing industry has always been driven to find ways of processing more food product faster, it has been more recently been tempered by the need to do so in a manner that ensures the food is not contaminated. Thus, there has been a move to not only heat the food products until they are cooked, but to pasteurize the food products which takes longer, requires more heat, and thus is more costly.

0011Consequently, there has arisen a great need for a method and rotary blancher that processes food products, including heavy and fragile food products, more efficiently and more quickly and which is capable or more cost-effectively cooking, blanching and pasteurizing food products.

SUMMARY OF THE INVENTION

0012A rotary blancher and method of processing food products by heating are provided. The blancher and method uses a heat transfer medium and heat transfer enhancers that include one or more of a high volume fluid, a high pressure fluid, or a high pressure and high volume fluid. In its preferred embodiment, the blancher includes a housing that has an inlet and an outlet and a food product-receiving chamber. Food products enter through the inlet, are received and heat in the food product-receiving chamber, and exit through the outlet. A rotary food product transport mechanism urges food products received in the chamber toward the outlet. While inside the chamber, a heat transfer medium heats the food products preferably to blanch, cook or pasteurize them. The heat transfer medium can be a liquid, such as water, or another fluid that can comprise a vapor, if desired.

0013In a preferred embodiment, the housing is comprised of a tank and preferably includes a cover that can be attached to the tank in a clamshell arrangement. The rotary food product transport mechanism preferably comprises an auger or screw disposed in the tank and which is made of helical spaced apart flights. If desired, one or more of the flights can carry one or more mechanical agitation devices, such as generally radially extending baffles. Preferably, the auger is disposed in a perforate drum that is received in the blancher housing. An exemplary blancher of the aforementioned construction has a length that typically is four feet or longer.

0014The blancher includes a plurality of orifices that discharge fluid into the heat transfer medium. In one embodiment, the discharged fluid forms directed flows that help break up food products and help prevent food products from clumping together. One or more flows of fluid can be directed at one or more locations within the blancher where food products tend to gather to break up clumps as well as to prevent clumping.

0015In another embodiment, there is a plurality of spaced apart manifolds that each has at least a plurality of orifices through which fluid is discharged. One or more manifolds can be disposed below the lid in communication with the tank in a quadrant of the tank adjacent the direction of rotation of the auger. Preferably, the manifolds are spaced apart. One or more manifolds, or groups of orifices, can be disposed around the periphery of the auger at or adjacent one or more of the following positions: 3 o'clock, 4 o'clock, 5 o'clock, 6 o'clock, 7 o'clock, 8 o'clock, and 9 o'clock positions. In another preferred arrangement, one or more manifolds, or groups of orifices, are located between at least one or more of the following positions: between 3 o'clock and 4 o'clock, between 4 o'clock and 5 o'clock, between 5 o'clock and 6 o'clock, between 5 o'clock and 7 o'clock, between 6 o'clock and 7 o'clock, between 7 o'clock and 8 o'clock and/or between 8 o'clock and 9 o'clock.

0016In a still further preferred embodiment, one or more manifolds or groups of orifices can be disposed between 3 o'clock and 5 o'clock or lie within a band located between 45° and 65° from a perpendicular drum centerline in a direction opposite the direction of drum rotation (measured from the center of the drum and centerline). One or more manifolds or groups of orifices can be disposed between 4 o'clock and 6 o'clock or lie within a band located between 25° and 40° from the centerline in a direction opposite the direction of drum rotation. One or more manifolds or groups of orifices can be disposed between 5 o'clock and 7 o'clock or lie within ±25° of the centerline. One or more manifolds or groups of orifices can be disposed between 6 o'clock and 8 o'clock or lie within a band located between 25° and 40° from the centerline in a direction the same as the direction of drum rotation. One or more manifolds or groups of orifices can be disposed between 7 o'clock and 9 o'clock or lie within a band located between 45° and 65° from the centerline in a direction the same as the direction of drum rotation.

0017The fluid discharged can comprise liquid, such as water, or gas, such as air. If desired, vapor, such as steam or water vapor, can be discharged. Liquid can be discharged from one or more groups each comprising one or more orifices, and/or gas can be discharged from one or more different groups each comprising one or more orifices. If desired, vapor can be discharged from one or more groups of one or more orifices.

0018Where liquid is discharged, it preferably is either discharged at a high flow rate, a high pressure, or both. For example, where liquid is discharged, it preferably is discharged at a flow rate of at least 20 gallons per minute (gpm) at a pressure of at least 30 psi. Where liquid is discharged at a higher flow rate, the liquid is discharged at a flow rate of at least 60 gpm. Preferably, at least 60 gpm per foot (gpm/ft) of blancher length is discharged. In another preferred method, at least 80 gpm per minute is discharged. Where liquid is discharged at a higher pressure, it preferably is discharged at a pressure of at least 80 psi. Where the pressure is at least 80 psi, at least 20 gpm/ft preferably is discharged.

0019Where gas is discharged, it preferably is either discharged at a high flow rate, a high pressure, or both. For example, where gas is discharged, it preferably is discharged at a flow rate of at least 60 CFM at a pressure of at least 2 psi. In another preferred method, the gas is discharged at a higher flow rate of at least 100 CFM. Preferably, at least 100 CFM per foot (CFM/ft) of blancher length is discharged. In still another preferred method, the gas is discharged at an even higher flow rate of at least 200 CFM. Preferably, at least 200 CFM/ft is discharged. Where gas is discharged at a high pressure, it preferably is discharged at a pressure of at least 80 psi. Where the pressure is at least 80 psi, at least 10 CFM/ft is discharged.

0020If desired, vapor, such as steam, can be discharged from one or more of the orifices at the above-mentioned gas flow rates and pressures. Where steam is discharged, it preferably is discharged from each orifice at a flow rate of at least 20 pounds per hour (lbs/hr) at a discharge flow rate of at least 15 psi.

0021In one preferred method, high pressure, high volume or high pressure and high volume liquid and gas is discharged into a liquid heat transfer medium to help in the processing of relatively heavy food products having a density of at least 55 lb/ft³. Such food products include hot dogs, pouched hot dogs, meats, pouched meats, and other heavier food products. If desired, one or more flights carry one or more direct-contact mechanical agitation devices that can be radially extending baffles. Discharging such liquid and gas, a blancher can process at least eight inches of depth of such relatively heavy food product, and preferably at least twelve inches of depth of the food product, in the food product receiving chamber. Discharging such liquid and gas, a blancher can process at least 8000 lbs/hr of food product, and preferably at least 10000 lbs/hr of food product. Preferably, the food product-receiving chamber is disposed in the drum that surrounds the auger.

0022In another preferred method, high pressure, high volume, or high pressure, high volume gas is discharged into a liquid heat transfer medium to help in the processing of food products having a density of no more than 55 lb/ft³and to help process more fragile food products. An example of such a food product that is relatively fragile is pasta. Preferably, none of the flights are equipped with direct-contact mechanical agitation devices. Discharging such gas, a blancher can process at least eight inches of depth of food product, and preferably at least twelve inches of depth of food product, in the food product-receiving chamber. Discharging such gas, a / can process at least 4500 lbs/hr of food product, and preferably at least 7000 lbs/hr of food product.

0023In another preferred embodiment and method, heat transfer medium and atmosphere within a blancher can be withdrawn and returned to the blancher in the form of gas, vapor and/or liquid discharged through one or more the orifices. Where the fluid is recirculated, a pump such as a liquid-ring vacuum pump or compressor is used to withdraw fluid from the blancher through a conduit and deliver the withdrawn fluid to one or more orifices or one or more manifolds.

0024It is an object of the present invention to utilize higher pressure directed flows of fluid inside the blancher to increase turbulence and heat transfer to the food products inside the blancher.

0025It is another object of the present invention to utilize higher flow rate directed flows of fluid inside the blancher to increase turbulence and heat transfer to the food products inside the blancher.

0026It is still another object of the present invention to utilize higher pressure and higher flow rate directed flows of fluid inside the blancher to increase turbulence and heat transfer to the food products inside the blancher.

0027It is a still further advantage of the present invention to utilize at least some of the heat transfer medium and/or atmosphere from within the blancher as a source of the directed fluid flows.

0028It is an advantage of the present invention to utilize higher flow rate and/or higher pressure directed flows of gas inside the blancher to increase the buoyancy of food products inside the blancher to prevent them from gathering near the bottom.

0029It is another advantage of the present invention to increase the amount of food products that can be substantially simultaneously processed at one time.

0030It is an additional advantage of the present invention to prevent food products in the blancher from clumping together with other food products.

0031It is a still another advantage of the present invention to significantly increase the rate of food product processing.

0032It is a further advantage of the present invention to reduce and preferably substantially completely prevent damage to fragile food products, such as pasta.

0033It is another advantage of the present invention to increase the amount of fragile food products that can be substantially simultaneously processed at one time.

0034It is a still another advantage of the present invention to significantly increase the rate of processing of relatively fragile food products.

0035It is another advantage of the present invention to increase the amount of relatively heavy food products that can be substantially simultaneously processed at one time.

0036It is a still another advantage of the present invention to significantly increase the rate of processing of relatively heavy food products.

0037It is a further advantage of the present invention to reduce and preferably substantially completely prevent damage to relatively heavy food products, such as hot dogs and turkey breasts.

0038Other advantages, features and objects of the present method is that it saves processing time, increases production, is economical, is versatile in that it can be employed in the blanching, cooking or pasteurizing of food products, is capable of recirculating the discharged fluids to save energy, and is simple, reliable, easy to control, and can be used to help process many different types of food products.

0039Additional objects, features and objects of the invention include a blancher that is simple, reliable, rugged, durable, and which is of economical construction and which is easy to make and assemble.

0040Other objects, features, and advantages of the present invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

0041At least one preferred exemplary embodiment of the invention is illustrated in accompanying drawings in which the reference numerals represent like parts roughout and in which:

0042<figref idref="DRAWINGS">FIG. 1</figref> is an exploded perspective view of a rotary blancher of this invention;

0043<figref idref="DRAWINGS">FIG. 2</figref> is a side view of the rotary blancher with a section broken away;

0044<figref idref="DRAWINGS">FIG. 3</figref> is a sectional view of the blancher taken along line <b>3</b>—<b>3</b> of <figref idref="DRAWINGS">FIG. 2</figref> with its cover removed and depicting an orifice from which fluid is being injected toward food products in a drum of the blancher;

0045<figref idref="DRAWINGS">FIG. 4</figref> is a sectional view of the orifice and blancher taken along line <b>4</b>—<b>4</b> of <figref idref="DRAWINGS">FIG. 3</figref>;

0046<figref idref="DRAWINGS">FIG. 5</figref> is a sectional view of another preferred blancher embodiment;

0047<figref idref="DRAWINGS">FIG. 6</figref> is a sectional view of still another preferred blancher embodiment;

0048<figref idref="DRAWINGS">FIG. 7</figref> is a sectional view of a further preferred blancher embodiment;

0049<figref idref="DRAWINGS">FIG. 8</figref> is a sectional view of a still further preferred blancher embodiment;

0050<figref idref="DRAWINGS">FIG. 9</figref> is a sectional view of a blancher with a schematic depiction of recirculation systems for recirculating fluid from the blancher; and

0051<figref idref="DRAWINGS">FIG. 10</figref> is a sectional view of a blancher with a schematic depiction of recirculation systems for heating and recirculating fluid from the blancher.

DETAILED DESCRIPTION

0052<figref idref="DRAWINGS">FIGS. 1-4</figref> illustrate an exemplary rotary blancher <b>20</b> of this invention that utilizes directed flows of a fluid during operation to enhance heat transfer. As is shown more clearly in <figref idref="DRAWINGS">FIG. 6</figref>, the blancher <b>20</b> is comprised of a housing that includes a cover <b>22</b> that mates with a tank <b>24</b> that holds a heated fluid, that preferably is a liquid <b>26</b>, which heats food products <b>32</b> during operation. The tank <b>24</b> is supported by a frame <b>28</b> that has legs <b>30</b>, which rest on the floor or ground.

0053The tank <b>24</b>, preferably made of stainless steel or another material suitable for food processing applications, has an inlet endwall <b>34</b> and an outlet endwall <b>36</b>. The endwalls <b>34</b> and <b>36</b> are joined to a tank underside <b>38</b> that defines the bottom and lengthwise sides of the tank <b>24</b>. The tank underside <b>38</b> may be a single, continuous, curved plate running lengthwise between endwalls <b>34</b> and <b>36</b>, or may be made of several long flat plates positioned side by side and angularly joined together to form a generally curved shape. Each endwall <b>34</b> and <b>36</b> has a through opening, <b>40</b> and <b>42</b> respectively, that preferably is arcuate or semicircular.

0054A food product transport mechanism <b>44</b> is received within the blancher <b>20</b> and preferably is disposed between the tank underside <b>38</b> and cover <b>22</b>. The food product transport mechanism <b>44</b> is constructed and arranged to transport food products <b>32</b> received in blancher <b>20</b> toward the blancher outlet <b>62</b>. In its preferred embodiment, the food product transport mechanism <b>44</b> comprises an auger or helical screw <b>48</b> received within the blancher <b>20</b> and which rotates during operation to urge food products <b>32</b> received in the blancher <b>20</b> toward the outlet <b>62</b>.

0055The auger <b>48</b> has a plurality of pairs of axially spaced apart and interconnected flights <b>50</b> and extends substantially the length of the interior of the tank <b>24</b>. Preferably, the auger <b>48</b> has at least four flights and can have as many as twenty flights or more depending upon the application and length of the blancher <b>20</b>. While the auger flights <b>50</b> can be carried by an elongate generally cylindrical central support core <b>51</b> (FIG. <b>3</b>), the auger <b>48</b> can be of a coreless construction, such as is shown in <figref idref="DRAWINGS">FIGS. 1 and 2</figref>.

0056Preferably, the auger <b>48</b> is housed in a drum <b>52</b>. The drum <b>52</b> has a sidewall <b>54</b>, an inlet endwall <b>56</b>, an outlet endwall <b>58</b>, and inlet and outlet <b>60</b> and <b>62</b>, through which food products <b>32</b> are introduced into the blancher <b>20</b> and discharged from the / <b>20</b>. Annular drum journals <b>64</b> extend from each end of the drum <b>52</b> beyond each drum endwall <b>54</b> and <b>56</b>. Each journal <b>64</b> provides a support surface upon which the weight of the drum <b>52</b> can rest particularly while it rotates during operation. Preferably, each drum journal <b>64</b> is rotatively supported on trunnions <b>66</b> which are mounted to the frame <b>28</b> and which are positioned so that the weight of the drum <b>52</b> does not rest upon the tank endwalls <b>34</b> and <b>36</b>.

0057The drum <b>52</b> is constructed and arranged to receive food products <b>32</b> and a heat transfer medium <b>33</b> (<figref idref="DRAWINGS">FIG. 3</figref>) such that the heat transfer medium <b>33</b> can surround and contact the food products <b>32</b> within the drum <b>52</b> during operation. In its preferred embodiment, the drum <b>52</b> is of perforate construction. For example, the drum sidewall <b>54</b> can be constructed with a plurality of perforations <b>68</b> and is preferably made of perforated panels, mesh, or a screen-like material in order to contain the food products <b>32</b> in the drum <b>52</b> while at the same time permitting the heat transfer medium <b>33</b> to enter the interior of the drum, preferably through the perforations <b>68</b>, to contact the food products <b>32</b>.

0058Each of the perforations <b>68</b> in the portion of the drum sidewall <b>54</b> shown in <figref idref="DRAWINGS">FIG. 2</figref> is exaggerated for clarity. Preferably, the perforations <b>68</b> are constructed and arranged to permit heat transfer medium <b>33</b> to flow through the sidewall <b>52</b> into or out of the drum <b>50</b> while retaining the food product <b>42</b> in the drum <b>50</b>. Depending on the type of food product <b>32</b> being processed, the size and shape of the perforations <b>68</b> can vary. Preferably, the size of each perforation <b>68</b> can range from as small as ⅙ of an inch, for relatively small food product, such as rice, to as large as ½ inch or more for larger food products, such as hot dogs or the like. The sizes of the perforations preferably are selected using routine testing and experimentation to help maximize the flow of the directed flows of fluid through the drum sidewall <b>54</b>.

0059Particularly where the auger <b>48</b> is of coreless construction, the drum <b>52</b> can be constructed with circumferentially spaced apart elongate struts <b>70</b> that preferably extend from one end wall <b>56</b> to the other end wall <b>58</b> to help strengthen and rigidify the drum <b>52</b> and auger <b>48</b>. These struts <b>68</b> can also serve as mounts to which the panels that make up the perforate drum sidewall <b>54</b> can be fastened. Preferably, the panels are removably fastened to the struts <b>68</b>.

0060In its preferred embodiment, the cover <b>22</b> is of preferably elongate and vaulted construction so as to fit over and completely cover the tank <b>24</b> so as to provide an enclosure for receiving the heat transfer medium <b>33</b> and a food product receiving chamber for receiving the food products <b>32</b>. The cover <b>22</b> has a pair of endwalls <b>80</b> and <b>82</b> and each endwall has a semi-circular opening <b>76</b>. When the cover <b>22</b> is closed, one of the openings <b>76</b> is positioned above one of the openings <b>40</b> in tank endwall <b>34</b> and the other one of the openings <b>76</b> is positioned above the other one of the openings <b>42</b> in tank endwall <b>36</b>. When closed, one of the drum journals <b>64</b> extends out from openings <b>76</b> and <b>42</b> and the other one of the journals <b>64</b> extends out from openings <b>76</b> and <b>40</b>.

0061The cover <b>22</b> can be attached to the tank <b>24</b> in a manner such that it can be moved relative to the tank <b>24</b> to permit access to the interior of the blancher <b>20</b>. The cover <b>22</b> can be attached to the tank <b>24</b> by one or more hinges such that it may be opened along one side of the blancher <b>20</b>. If desired, the cover <b>22</b> can be attached to the tank <b>24</b> such that it can be lifted free of the tank <b>24</b> using cylinders or the like, such as in the manner disclosed in U.S. Pat. No. 4,788,476 to Zittel, the disclosure of which is hereby incorporated by reference.

0062The blancher <b>20</b> preferably also has an inlet <b>84</b> permitting introduction of the heat transfer medium <b>33</b> into the tank <b>28</b> and an outlet <b>86</b> through which the heat transfer medium <b>33</b> can be drained. If desired, there can be a constant flow of heat transfer medium <b>84</b> and outlet <b>86</b>. The outlet <b>84</b> and <b>86</b> can also assist in cleaning the interior of the tank <b>24</b>.

0063During operation, the auger <b>48</b> is rotated to urge the food products <b>32</b> through the blancher <b>20</b>. Preferably, both the auger <b>48</b> and the drum <b>52</b> rotate. If desired, the auger <b>48</b> and drum <b>52</b> can be constructed such that the auger <b>48</b> rotates relative to or independently of the drum <b>52</b>. While use of a drum <b>52</b> is preferred, depending upon the construction of the tank <b>24</b>, as well as other components of the blancher <b>20</b>, and the food processing application, a drum <b>52</b> may not be needed.

0064In one preferred embodiment, the drum <b>52</b> and auger <b>48</b> are driven by a motor (not shown) which transfers power via a geartrain, belt, or chain (also not shown) to a drive sprocket <b>72</b> carried by either of the drum journals <b>64</b>. The drum <b>52</b> preferably rotates at a speed selected to achieve the desired cooking time for the type of food product <b>32</b>, its weight, the amount being processed, and other factors, thereby controlling its residency time within the blancher <b>20</b> and thus its time of exposure to the heat transfer medium <b>33</b>.

0065When one or more of the food products <b>32</b> in the blancher <b>20</b> reaches the outlet <b>62</b>, each food product <b>32</b> is lifted and transferred to the outlet <b>62</b> where it is expelled out of the blancher <b>20</b>. A single generally radially extending lifting flight <b>74</b>, or more than one, can be used to transfer the food products <b>32</b> to the outlet <b>62</b>. Of course, other suitable arrangements can be used to remove food product <b>32</b> from the blancher <b>20</b>.

0066Referring to <figref idref="DRAWINGS">FIG. 3</figref>, to help agitate food products <b>32</b> and help break up food products <b>32</b> that have clumped together, a baffle or ramp <b>88</b>, carried by at least one of the auger flights <b>50</b> and/or the drum sidewall <b>54</b>, can physically contact individual food products <b>32</b>. In a preferred embodiment shown in <figref idref="DRAWINGS">FIG. 4</figref>, the baffle <b>88</b> comprises a plate <b>90</b> that extends between adjacent auger flights <b>50</b>. Preferably, the baffle <b>88</b> forms an acute vee with the drum sidewall <b>54</b> that has its apex pointed in the direction of rotation of the drum <b>52</b>. One end of the baffle <b>88</b> is located adjacent the drum sidewall <b>54</b> and preferably is disposed against the sidewall <b>54</b> or close enough to the sidewall <b>54</b> such that food products <b>32</b> will not get caught between the drum <b>52</b> and baffle <b>88</b>. If desired, the free end of each baffle <b>88</b> can be equipped with a lip <b>92</b>, preferably for preventing damage to food products <b>32</b> as they tumble off the plate <b>90</b>.

0067In one preferred embodiment, each baffle <b>90</b> forms an acute angle of between about 5° and about 35° with the drum sidewall <b>54</b> for helping to efficiently physically contact, lift and agitate food products <b>32</b> that come into contact with the baffles. In another preferred embodiment, particularly where the food products <b>32</b> are heavy, each baffle <b>90</b> forms an acute angle of between about 30° and about 45° with the sidewall <b>54</b>.

0068Preferably, there are between one and four circumferentially spaced apart baffles between at least one pair of adjacent flights <b>50</b>. Preferably, there are between one and four baffles between each pair of adjacent auger flights <b>50</b>. In the preferred embodiment shown, each baffle is of substantially flat construction. In another preferred embodiment, the baffle is of non-straight construction and preferably is curved. If desired, the baffle can further comprise bars or posts that extend outwardly from the plate.

0069The baffles <b>88</b> orbit the center of the drum <b>52</b> as the drum rotates. After entering the heat transfer medium <b>33</b>, each baffle <b>88</b> wedges between one or more food products <b>32</b> near the drum sidewall <b>54</b> or near the bottom of the drum <b>52</b> and urges the food products <b>32</b> away from the sidewall <b>54</b>. As the drum <b>52</b> further rotates, the food products <b>32</b> slide or tumble along the baffle <b>88</b> until each food product <b>32</b> falls or tumbles off of the baffle <b>88</b>. In doing so, food products <b>32</b> that have gathered along the bottom of the drum <b>52</b> are lifted and mixed with the heat transfer medium. As a result of this mechanical agitation by physical contact, clumps of food products <b>32</b> are broken up and heat transfer is increased.

0070The blancher <b>20</b> is equipped with a plurality of pairs of orifices <b>94</b> (at least three orifices <b>94</b>) from which directed flows, jets, or streams of a fluid are discharged into the tank <b>24</b> to displace food products <b>32</b> in the drum <b>52</b> to help increase heat transfer. The orifices <b>94</b> are connected to a common manifold <b>96</b> that is in turn connected to a source of fluid (not shown). In one preferred embodiment, the fluid source comprises a source of liquid, preferably a source of water. In another preferred embodiment, the fluid source comprises a source of gas, preferably a source of air.

0071As is depicted in <figref idref="DRAWINGS">FIG. 4</figref>, each orifice <b>94</b> can include a nozzle <b>98</b>, if desired. In the exemplary orifice arrangement shown in <figref idref="DRAWINGS">FIG. 4</figref>, the orifice <b>94</b> includes a first conduit <b>100</b> connected at an angle to a second conduit <b>102</b> attached to a necked down or tapered section <b>104</b> from which the nozzle <b>98</b> extends. The orifice <b>94</b> extends through or communicates with an opening in the tank bottom <b>38</b> to enable a flow <b>106</b> of the fluid to be directed toward the drum <b>52</b> with enough force such that at least some of the fluid flow <b>106</b> passes through the perforations <b>68</b> in the drum sidewall <b>54</b> and impinges against food products <b>32</b> in the drum <b>52</b> causing at least some of the food products <b>32</b> to be displaced.

0072Referring to <figref idref="DRAWINGS">FIG. 1</figref>, the manifold <b>96</b> has a plurality of pairs of orifices <b>94</b> that each direct fluid flow <b>106</b> into the drum <b>52</b>. In a preferred embodiment, there is at least one orifice <b>94</b> for each auger flight <b>50</b>. In another preferred embodiment, there are at least two orifices for each auger flight <b>50</b>. For example, for at least a portion of the axial length of the blancher <b>20</b> shown in <figref idref="DRAWINGS">FIG. 2</figref>, there are two orifices <b>94</b> for each auger flight <b>50</b>. Each orifice <b>94</b> is disposed between a pair of adjacent auger flights <b>50</b>. If desired, two or more orifices <b>94</b> can be disposed between a pair of adjacent auger flights <b>50</b> with one or more of the orifices <b>94</b> being directed toward one or both of the flights <b>50</b>. While an orifice <b>94</b> can be located anywhere between adjacent auger flights <b>50</b>, at least one orifice <b>94</b> can be located adjacent the auger flight <b>50</b> of the adjacent pair that is located closest to the blancher inlet <b>60</b> for agitating food products <b>32</b> being contacted and urged by that flight <b>50</b>.

0073In one preferred embodiment, orifices <b>94</b> are located between the 6 o'clock and 9 o'clock position when the drum <b>52</b> is rotating in the clockwise direction, such as is the direction depicted in FIG. <b>3</b>. Thus, in tis preferred embodiment, orifices <b>94</b> direct flows <b>106</b> into the heat transfer medium <b>33</b> in the quadrant of the drum <b>52</b> adjacent or along where the drum sidewall <b>54</b> leaves the heat transfer medium <b>33</b> during rotation. Where rotation is opposite to that shown in <figref idref="DRAWINGS">FIG. 3</figref> (i.e., counterclockwise), the orifices <b>94</b> are located between 3 o'clock and 6 o'clock.

0074In one preferred embodiment, orifices <b>94</b> are positioned to aim flows <b>106</b> toward the drum interior and preferably generally toward the center of the drum <b>52</b>. In another preferred embodiment, at least a plurality of orifices <b>94</b> are aimed at a target point <b>108</b> where food products <b>32</b> tend to conglomerate while the drum <b>52</b> is rotating. Such a point <b>108</b> can be determined by routine testing and experimentation and its location will depend upon, among other factors, the type, size, shape, weight, and amount of the food product <b>32</b> being processed.

0075While the manifold <b>96</b> and at least a portion of the orifices <b>94</b> can be disposed outside the tank <b>52</b>, such as in the manner depicted in <figref idref="DRAWINGS">FIGS. 3 and 4</figref>, the orifices <b>94</b>, and if desired, the manifold <b>96</b>, can be disposed inside the tank <b>24</b>, such as is depicted in <figref idref="DRAWINGS">FIG. 5</figref>, so that fluid flows <b>106</b> are expelled from the orifices <b>94</b> more closely to the food products <b>32</b> to more vigorously displace and agitate them. Where the manifold <b>96</b> and orifices <b>94</b> are disposed outside the tank <b>24</b>, the location of each orifice <b>94</b> from which the fluid flows <b>106</b> are discharged is no farther than about twelve inches away from the outside of the drum sidewall <b>54</b>. Where located outside the tank <b>24</b>, the discharge opening <b>110</b> (<figref idref="DRAWINGS">FIG. 4</figref>) of each orifice <b>94</b> can be disposed in the tank <b>24</b> and preferably is located no farther away than six inches from the sidewall <b>54</b>. Where orifices <b>94</b> are disposed inside the tank <b>24</b>, a discharge opening of each in-tank orifice <b>94</b> is located closer than six inches because typically there is no more than about six inches between the tank <b>24</b> and drum sidewall <b>54</b>. Where orifices <b>94</b> are disposed inside the tank <b>24</b>, they preferably have discharge openings <b>110</b> located between about three inches and about one inch away from the sidewall <b>54</b>. In one preferred embodiment, the discharge opening <b>110</b> of each in-tank orifice <b>94</b> is located about two inches away from the sidewall <b>54</b>.

0076Where a liquid is being expelled from the orifices <b>94</b>, the liquid is expelled at a flow rate of at least 60 gpm/ft to more vigorously agitate and displace food products <b>32</b>. Preferably, the liquid is expelled from each orifice <b>94</b> at a flow rate of at least 20 gpm. In another preferred embodiment, the liquid is expelled from each orifice <b>94</b> at a flow rate of at least 60 gpm. Preferably, the liquid is expelled from each orifice <b>94</b> at a pressure of at least about 30 psi.

0077In another preferred method that can be dependent upon the type of food product being processed, liquid is expelled from the orifices <b>94</b> at a pressure of at least about 40 psi at a flow rate of at least about 80 gpm/ft. Preferably, the liquid is expelled from each orifice <b>94</b> at a flow rate of at least about 80 gpm. If desired, higher-pressure water having a pressure of at least 80 psi and a flow rate of at least 20 gpm/ft can be used. Preferably, at least 20 gpm is discharged from each orifice that is discharging water.

0078Where a liquid is being expelled, the opening of each orifice <b>94</b> can be as large as about ½ inch. Where round pipe is used, the pipe opening or outlet can have as large as ½ inch inside diameter.

0079Where a gas is expelled from the orifices <b>94</b>, the gas preferably is expelled at a flow rate of at least 100 CFM/ft. Preferably, the gas is discharged at a flow rate of 60 CFM from each orifice. Preferably, the gas is discharged at a pressure of at least 2 psi. In another preferred method that can be dependent on the type of food product being processed, the gas preferably is expelled at a pressure of at least 2 psi at a flow rate of no less than about 200 CFM/ft. In a still further preferred method, higher-pressure gas having a pressure of at least 60 psi and a flow rate of 10 standard cubic feed per minute per foot (SCFM/ft) of blancher length is used. In this instance, the flow rate discharged from each orifice is at least 10 CFM.

0080Where a gas is being expelled, the orifice opening can be as large as about ¼ inch. Where round pipe is used, the pipe opening or outlet can have as large as ⅛ inch inside diameter.

0081If desired, vapor, such as steam, can also be discharged from one or more of the orifices <b>94</b> at the above-mentioned gas flow rates and pressures. Where steam is discharged, it preferably is discharged from one or more orifices at a flow rate of at least 20 pounds per hour from each orifice discharged at a discharge flow rate of at least 15 psi.

0082Where water is the liquid being expelled, one or more centrifugal-type water pumps can be used to achieve the aforementioned high flow rates and high pressures. If desired, one or more positive displacement sanitary pumps or liquid-ring vacuum pumps can also be used to deliver water at these high pressures and/or at these high flow rates. More than one such device for supplying water at the desired high flow rate and/or high pressure can be used. For example, as many as three or more such devices can be used to deliver a sufficiently high flow rate of water at a sufficient pressure to a single manifold.

0083Where air is the gas being expelled, an air compressor can be used to achieve the aforementioned high volumes and high pressures. If desired, a squirrel cage blower, a regenerative blower, or a liquid-ring vacuum pump can be used to deliver air at these high pressures and/or at these high volumes. More than one such device for supplying air at the desired high flow rate and/or high pressure can be used. For example, as many as three or more such devices can be required to deliver a sufficient volume of air at a sufficient pressure to a single manifold.

0084In its preferred embodiment, the manifold <b>96</b> is a pipe from which two or more orifices <b>94</b> extend. Referring to <figref idref="DRAWINGS">FIG. 2</figref>, while the manifold <b>96</b> can extend axially the length of the blancher <b>20</b>, it can be broken up into two or more smaller manifolds each having a length less than the blancher <b>20</b> that are each connected to a separate fluid delivery source, system, or device. While the manifold <b>96</b> shown in <figref idref="DRAWINGS">FIG. 2</figref> has a single inlet <b>112</b> and a single outlet <b>114</b>, the manifold <b>96</b> can be equipped with more than one inlet where more than one fluid delivery source, system or device is connected to the manifold <b>96</b>. The manifold outlet <b>114</b> can be capped, such as is shown in <figref idref="DRAWINGS">FIG. 1</figref>, or it can have a return, if desired. Other arrangements for connecting more than one fluid delivery source, system or device can be used.

0085<figref idref="DRAWINGS">FIG. 5</figref> depicts a preferred embodiment of the invention having at least a plurality of spaced apart banks <b>116</b> of orifices <b>94</b> disposed around the food products <b>32</b> being processed with the banks <b>116</b> located between 3 o'clock and 9 o'clock. In this preferred embodiment, the blancher <b>20</b> has seven banks <b>116</b>a, <b>116</b>b, <b>116</b>c, <b>116</b>d, <b>116</b>e, <b>116</b>f, and <b>116</b>g. Of course, a blancher can be equipped with more or less than seven banks. The banks <b>116</b>a-<b>116</b>g can be generally equi-angularly spaced apart, if desired, and are shown in <figref idref="DRAWINGS">FIG. 5</figref> as being located at about 3 o'clock, 4 o'clock, 5 o'clock, 6 o'clock, 7 o'clock, 8 o'clock, and 9 o'clock positions. Preferably, bank <b>116</b>a is located between 3 o'clock and 4 o'clock, bank <b>116</b>b is located between 4 o'clock and 5 o'clock, bank <b>116</b>c is located between 5 o'clock and 6 o'clock, bank <b>116</b>d is located between 5 o'clock and 7 o'clock, bank <b>116</b>e is located between 6 o'clock and 7 o'clock, bank <b>116</b>f is located between 7 o'clock and 8 o'clock and bank <b>116</b>g is located between 8 o'clock and 9 o'clock.

0086Preferably, the blancher <b>20</b> is equipped with at least two banks of orifices <b>94</b> with both banks located in the exiting quadrant <b>118</b> of the tank <b>24</b> along where the drum sidewall <b>54</b> exits the heat transfer medium <b>33</b> during rotation. In the present case, since the drum <b>52</b> is depicted rotating clockwise, the exiting quadrant <b>118</b> extends from 6 o'clock to no more than 9 o'clock or about 90° from perpendicular drum centerline <b>120</b> (extends through center of drum) in the direction of drum rotation. Where the drum <b>52</b> is rotating clockwise, the exiting quadrant extends from 6 o'clock to no more than about 3 o'clock or no more than 90° from centerline <b>120</b> in the opposite direction.

0087The orifices <b>94</b> in a particular bank preferably all expel the same type of fluid in flow <b>106</b>. If desired, the orifices <b>94</b> in all of the banks can all expel the same type of fluid in flow <b>106</b>. However, different types of fluid can be discharged from different orifices <b>94</b>, if desired. For example, where the food products <b>32</b> are relatively heavy, liquid can be expelled from the orifices <b>94</b> of at least one bank and gas can be expelled from orifices <b>94</b> of at least one other bank not expelling liquid. g

0088In one preferred arrangement, the orifices <b>94</b> of banks <b>116</b>a, <b>116</b>c, <b>116</b>e, and <b>116</b>g all expel a gas at a high volume and the orifices <b>94</b> of the remaining banks <b>116</b>b, <b>116</b>d and <b>116</b>f all expel water at a high volume. In another preferred arrangement, orifices <b>94</b> of one or more of banks <b>116</b>c, <b>116</b>e, and <b>116</b>d expel a gas, preferably air, while the orifices <b>94</b> of one or more of the remaining banks, <b>116</b>a, <b>116</b>b, <b>116</b>f and <b>116</b>g, expel a liquid that preferably is water.

0089In still another preferred arrangement, only banks in the exiting quadrant are used, e.g. between 6 o'clock and 9 o'clock in <figref idref="DRAWINGS">FIG. 5</figref>, with the orifices <b>94</b> of at least one of the banks ejecting air and the orifices <b>94</b> of at least one other of the banks ejecting water. For example, the orifices <b>94</b> of at least one of banks <b>116</b>d and <b>116</b>g eject water and the orifices <b>94</b> of at least one of banks <b>116</b>e and <b>116</b>f eject air. If desired, the orifices <b>94</b> of at least one of banks <b>116</b>d and <b>116</b>g eject air and the orifices <b>94</b> of at least one of banks <b>116</b>e and <b>116</b>f eject water.

0090<figref idref="DRAWINGS">FIG. 6</figref> illustrates a preferred embodiment having banks <b>116</b>a, <b>116</b>b, <b>116</b>c, <b>116</b>d, <b>116</b>e, <b>116</b>f, and <b>116</b>g of orifices <b>94</b> that discharge liquid and banks <b>116</b>h, <b>116</b>i, <b>116</b>j, <b>116</b>k, <b>116</b>l, <b>116</b>m, and <b>116</b>n of orifices <b>94</b> that discharge gas. Preferably, bank <b>116</b>h is located between 3 o'clock and 4 o'clock, bank <b>116</b>i is located between 4 o'clock and 5 o'clock, bank <b>116</b>j is located between 5 o'clock and 6 o'clock, bank <b>116</b>k is located between 5 o'clock and 7 o'clock, bank <b>116</b>i is located between 6 o'clock and 7 o'clock, bank <b>116</b>m is located between 7 o'clock and 8 o'clock, bank <b>116</b>n is located between 8 o'clock and 9 o'clock. One or more of banks <b>116</b>a-<b>116</b>g can be used and one or more of banks <b>116</b>h-<b>116</b>n can be used.

0091<figref idref="DRAWINGS">FIG. 7</figref> illustrates one preferred arrangement for processing relatively heavy food products <b>32</b> having a density of at least 55 lb/ft³. Examples of such food products include hot dogs, hot dogs in packages or pouches, turkey breasts, chicken breasts, beef patties, and steaks. Hot dogs, turkey breasts, and other meat products, for example, have a density of about 65 lb/ft³and therefore are difficult to uniformly heat, and are difficult to quickly pasteurize. The blancher <b>20</b> has at least one bank <b>116</b>e of orifices <b>94</b> located between 6 o'clock and 8 o'clock (or between 4 o'clock and 6 o'clock where the drum <b>52</b> is rotating counterclockwise) from which air is injected into a liquid heat transfer medium that preferably is water heated to a temperature above 120° Fahrenheit. Preferably, bank <b>116</b>e is located within 65° of centerline <b>120</b> in the direction of drum rotation. Since rotation is clockwise, bank <b>116</b>e is located within 65° to the left of centerline <b>120</b>. This injected air has the desired effect of making the relatively heavy food products <b>32</b> more buoyant and therefore easier to lift off the bottom of the drum <b>52</b>. The air also impinges against at least some of the food products near the bottom of the drum <b>52</b> physically urging them away from the bank <b>116</b>e and hence the drum sidewall <b>54</b>. This also desirably agitates at least some of the food products <b>32</b> in the drum <b>52</b> and thereby also improves heat transfer.

0092The blancher <b>20</b> has at least one bank <b>116</b>f of orifices <b>94</b> located between 7 o'clock and 9 o'clock from which water is injected into the water heat transfer medium <b>33</b>. Preferably, bank <b>116</b>f is located within a band that extends between 45° and 85° from centerline <b>120</b> in the direction of drum rotation. This injected water has the desired effect of forcefully churning the relatively heavy food products <b>32</b>, urging them away from the bank <b>116</b>f and drum sidewall <b>54</b>, breaking them up, and agitating them.

0093Baffles <b>88</b> are also used to physically contact food products <b>32</b> and move food products <b>32</b> that are clumped together in a direction away from the drum sidewall <b>54</b>. Thereafter, the combination of injected air and injected water helps urge the food products <b>32</b> toward the surface of the water <b>33</b>, breaking it up, all while intensely agitating the food products <b>32</b>. As a result of breaking up food products <b>32</b> that have clumped together, heat transfer is dramatically improved because the water <b>32</b> in the tank <b>24</b> can directly contact each of the food products <b>32</b>.

0094Although use of baffles <b>88</b> is preferred, they are not needed for all applications. For those applications not requiring baffles, a combination of gas injection and liquid injection, such as in the manner discussed above, can be used.

0095Either high volume air at a pressure of at least 2 psi and a volume of at least 60 SCFM/ft or high-pressure air at a pressure of at least 80 psi and a volume of at least 10 SCFM/ft is discharged from the orifices <b>94</b> of bank <b>116</b>e. Where the air is discharged at a pressure of less than 80 psi, at least 60 SCFM is discharged from each orifice <b>94</b> discharging air. Otherwise, at least 10 SCFM is discharged from each orifice <b>94</b> of each orifice that is discharging air. Either high volume water at a pressure of at least 30 psi and a flow rate of at least 80 gpm/ft or high-pressure water at a pressure of at least 80 psi and a flow rate of at least 20 gpm/ft is discharged from the orifices of bank <b>116</b>f. Preferably, at least 20 gpm is discharged from each orifice of each bank that is discharging water. If desired, one or more orifices <b>94</b> or banks of orifices can be employed that discharge a vapor that preferably is steam.

0096Because these relatively heavy food products <b>32</b> are also each relatively large in size, the drum sidewall perforations <b>68</b> each are at least ¾ inch in width or diameter. Preferably, for such large food products <b>32</b> the drum sidewall perforations <b>68</b> each can range in size (width or diameter) from ½ inch or ¾ inch.

0097Where the food products <b>32</b> are to be blanched and the heat transfer medium <b>33</b> in the tank <b>24</b> is water, the water <b>33</b> preferably is kept at a temperature above 185° Fahrenheit (F). Where the food products <b>32</b> are to be pasteurized, the water <b>33</b> is kept at a temperature above 120° F. and each food product <b>32</b> resides in the blancher <b>20</b> for at least 3 minutes and as long as 720 minutes. Preferably, pasteurization of these kinds of relatively heavy food products <b>32</b> at or above this temperature takes no more than about 4 minutes per food product <b>32</b>. The use of the aforementioned directed flows <b>106</b> advantageously reduces pasteurization time by as much as 25% while helping to ensure complete and uniform pasteurization of each food product.

0098More product can advantageously be blanched or pasteurized at one time. For example, where only a few inches of relatively heavy food product <b>32</b> can be processed in a prior art blancher at a given moment, at least double the food product depth can be processed in a blancher of this invention using a method of this invention. For example, no more than six inches depth of packaged hot dogs <b>32</b> can be blanched in a prior art 72 inch diameter blancher equipped only with baffles <b>88</b>, whereas at least eight inches and preferably at least twelve inches of depth of packaged hot dogs <b>32</b> can be blanched by a blancher <b>20</b> of the present invention that is also 72 inches in diameter. This also translates into dramatically increased throughput. More specifically, where a certain amount of food products <b>32</b> can be processed in a given hour using a prior art blancher, a blancher <b>20</b> of the present invention will process at least double that amount. For example, a 72-inch diameter blancher <b>20</b> of the present invention will process at least 6000 pounds per hour (lbs/hr) of relatively heavy food product <b>32</b> as compared to no more than 3000 lbs/hr for a prior art blancher of the same size. This is true for the processing of hot dogs or packaged hot dogs. Experiments with a prior art blancher equipped with baffles resulted in only 5000 lbs/hr of food product <b>32</b> being processed, whereas at least 10000 lbs/hr of the same food product <b>32</b> can be processed using a blancher <b>20</b> of this invention. Thus, the preferred arrangement can process at least 8000 lbs/hr of food product <b>32</b>.

0099<figref idref="DRAWINGS">FIG. 8</figref> depicts another arrangement of the invention that is used to process food products having a density no greater than 55 lb/ft³. This arrangement is suited for processing relatively fragile food products <b>32</b> that include, for example, pasta, lasagna, and tortellini. For exemplary purposes, pasta or lasagna food products <b>32</b> are shown in FIG. <b>8</b> and have a density of about 40 lb/ft³.

0100The arrangement shown in <figref idref="DRAWINGS">FIG. 8</figref> includes at least a plurality of pairs of spaced apart banks <b>116</b>b, <b>116</b>c, <b>116</b>d, <b>116</b>e and <b>116</b>f of orifices <b>94</b> that each deliver a fluid that preferably is a gas, namely air. Bank <b>116</b>b is disposed between 3 o'clock and 5 o'clock or lies within a band located between 45° and 65° from the perpendicular drum centerline <b>120</b> in a direction opposite the direction of drum rotation (measured from the center of the drum and line <b>120</b>). Bank <b>116</b>c is disposed between 4 o'clock and 6 o'clock or lies within a band located between 25° and 40° from the centerline <b>120</b> in a direction opposite the direction of drum rotation. Bank <b>116</b>d is disposed between 5 o'clock and 7 o'clock or lies within ±25° of the centerline <b>120</b>. Bank <b>116</b>e is disposed between 6 o'clock and 8 o'clock or lies within a band located between 25° and 40° from the centerline <b>120</b> in a direction the same as the direction of drum rotation. Bank <b>116</b>f is disposed between 7 o'clock and 9 o'clock or lies within a band located between 45° and 65° from the centerline <b>120</b> in a direction the same as the direction of drum rotation.

0101Air is discharged from the orifices <b>94</b> in each bank <b>116</b>b-<b>116</b>f either generally upwardly or generally toward the food products <b>32</b> in the drum <b>52</b> causing at least some of the air to become trapped in the food products <b>32</b> thereby increasing their buoyancy. By increasing the buoyancy of the food products <b>32</b> in the drum <b>52</b>, at least some of the food products <b>32</b> begin to float and rise from the bottom of the drum <b>52</b> (where the food products <b>32</b> are shown in FIG. <b>8</b>), and thereby become more directly exposed to the water heat transfer medium <b>33</b>. The discharged air also advantageously has the desired effect of churning the water <b>33</b> and also agitating the food products <b>32</b>. As a result of the high volumes and/or high pressures used, the agitation achieved is more vigorous and more forceful. All of this advantageously increases heat transfer to the food products <b>32</b> without requiring direct contact between food products <b>32</b> and mechanical agitation devices such as baffles. Thus, no baffles are needed and no baffles are shown in <figref idref="DRAWINGS">FIG. 8</figref> making this arrangement particularly suitable for processing relatively fragile food products.

0102Either high volume air at a pressure of at least 2 psi and a volume of at least 60 SCFM/ft or high pressure air at a pressure of at least 80 psi and a volume of at least 10 SCFM/ft is discharged from the orifices <b>94</b> of each bank of one or more of banks <b>116</b>b-<b>116</b>f. Preferably, at least 10 SCFM is discharged from each orifice <b>94</b> of each bank that is discharging air. Where pasta or pasta-based products <b>32</b> are processed, the drum sidewall perforations <b>68</b> each are no greater than 5/32 inch in width or diameter. During processing of these kinds of products, the water preferably is kept at a temperature of above 190° F. and can be cooked in the manner previously described, if needed.

0103If desired, one or more orifices <b>94</b> or banks of orifices <b>94</b> can be employed through which water is discharged. If desired, one or more orifices <b>94</b> or banks of orifices <b>94</b> can be employed through which steam is discharged.

0104More product can advantageously be blanched, cooked, or pasteurized at one time. For example, where only a few inches of relatively fragile pasta or lasagna <b>32</b> can be processed in a prior art blancher at a given moment, at least double the food product depth can be processed in a blancher of this invention. For example, where no more than six inches depth of pasta or lasagna can be blanched in a prior art 72 inch diameter blancher, at least eight inches and preferably at least twelve inches of depth of pasta or lasagna <b>32</b> can be blanched by a 72 inch diameter blancher <b>20</b> of the present invention. This also translates into dramatically increased throughput. More specifically, where a certain amount of food products <b>32</b> can be processed in a given hour using a prior art blancher, a blancher <b>20</b> of the present invention will process at least double that amount. For example, a 72-inch diameter blancher <b>20</b> of the present invention will process at least 4500 lbs/hr and preferably at least 7000 lbs/hr of pasta or lasagna <b>32</b> as compared to a prior art 72-inch diameter blancher, which can only process 3500 lbs/hr.

0105<figref idref="DRAWINGS">FIG. 9</figref> depicts a blancher <b>20</b> of this invention having at least one orifice <b>94</b> from which a fluid is discharged into the tank <b>24</b>. The discharged fluid is drawn from within the blancher <b>20</b> by a pump <b>122</b> that delivers the fluid to the orifice <b>94</b>. Such an arrangement advantageously conserves energy because it recirculates the fluid discharged into the blancher <b>20</b> lessening heat losses.

0106<figref idref="DRAWINGS">FIG. 9</figref> illustrates a first fluid recirculation system <b>124</b> where a liquid heat transfer medium <b>26</b> is disposed in the tank <b>24</b>. The system includes an inlet <b>126</b> through which liquid from the blancher <b>20</b> enters a conduit <b>128</b>. The liquid flows through the conduit <b>128</b> to a pump <b>122</b> that delivers the liquid via another conduit <b>130</b> to orifice <b>94</b>. The liquid is discharged through the orifice <b>94</b> into the tank <b>24</b>. In one embodiment, the orifice <b>94</b> is disposed so as to direct the liquid toward a particular location, such as the drum <b>52</b>, one or more food products <b>32</b> in the drum <b>52</b>, or a spot or region where food products <b>32</b> tend to congregate or clump. In the arrangement shown in <figref idref="DRAWINGS">FIG. 9</figref>, the inlet <b>126</b> is disposed below the water line of the liquid heat transfer medium <b>26</b> and above orifice <b>94</b>. If desired, the drum <b>52</b> can be equipped with one or more baffles <b>88</b>.

0107<figref idref="DRAWINGS">FIG. 9</figref> further illustrates a second fluid recirculation system <b>132</b> where atmosphere <b>134</b> within the blancher <b>20</b> is collected and discharged into the tank <b>24</b>. The atmosphere within the blancher typically comprises gas and vapor, typically air and water vapor, but can be comprised solely of a gas or a vapor. Where a liquid heat transfer medium <b>26</b> is used, the atmosphere <b>134</b> is disposed above the liquid <b>26</b>. The system includes an inlet <b>136</b> through which atmosphere <b>134</b> in the blancher <b>20</b> is drawn into a first conduit <b>138</b>. The atmosphere <b>134</b> flows through the conduit <b>138</b> to a pump <b>122</b>′ that delivers the atmosphere via a second conduit <b>140</b> to the other orifice <b>94</b>. The atmosphere <b>134</b> is then discharged through that orifice <b>94</b> into the tank.

0108In this manner, fluid used to move and agitate food products <b>32</b> in the blancher <b>20</b> is delivered to a single orifice <b>94</b>, a plurality of orifices <b>94</b>, a manifold <b>96</b> connected to a plurality of orifices <b>94</b>, or a plurality of manifolds <b>94</b>. One or more first and second fluid recirculation systems <b>124</b> and <b>132</b> can be used alone or in combination in a single blancher. The pump <b>122</b> preferably is a pump, a blower or a compressor capable of operating where moisture or liquid is present.

0109An example of a preferred pump for recirculating atmosphere is a liquid-ring vacuum pump or liquid-ring vacuum compressor. Examples of liquid-ring vacuum pumps or compressors are disclosed in U.S. Pat. Nos. 4,787,824 and 5,580,222, the disclosures of which are expressly incorporated herein. A liquid-ring vacuum pump or liquid-ring vacuum compressor is particularly preferred for pump <b>122</b>′ because of its ability to suck hot air carrying water vapor from inside the blancher <b>20</b> and deliver it under pressure to an orifice <b>94</b>, a plurality of orifices <b>94</b>, and/or one or more manifolds. This type of pump is also preferred because of its ability to be able to reliably pump air containing moisture for long periods of time and over a long service life all while withstanding a rather harsh operating environment.

0110<figref idref="DRAWINGS">FIG. 10</figref> illustrates first and second recirculation systems <b>124</b> and <b>132</b> each with a heater <b>142</b> that heats the fluid being recirculated. For example, the first recirculation system <b>124</b> includes a heater <b>142</b> that can be located upstream of the pump <b>122</b> to heat the liquid drawn from the blancher <b>20</b>. The second recirculation system <b>124</b> can also include a heater <b>142</b> that heats the atmosphere <b>134</b> drawn from within the blancher <b>20</b>. Examples of suitable fluid heaters <b>142</b> include gas fluid heaters and electric fluid heaters. Heated liquid, heated atmosphere, or heated vapor can be added to the fluid being recirculated. If desired, the heater <b>142</b> can be located downstream of the pump <b>122</b> or pump <b>122</b>′.

0111These recirculation systems advantageously conserve energy by recirculating already hot fluid from the blancher <b>20</b> thereby preventing the heat loss that would occur if cooler ambient air outside the blancher <b>20</b> or cooler plant water was instead used. If, desired, the first fluid recirculation system <b>124</b> and/or the second fluid recirculation system <b>132</b> shown in <figref idref="DRAWINGS">FIGS. 9 and 10</figref> can be used with any one of the arrangements depicted in <figref idref="DRAWINGS">FIGS. 1-8</figref> and can be used to recirculate liquid at flow rates and pressures less than those discussed above in association with the arrangements depicted in <figref idref="DRAWINGS">FIGS. 1-8</figref>.

0112In use, the blancher <b>20</b> of this invention is used to process food products <b>32</b> preferably by blanching or pasteurizing the food products <b>32</b>. Food product <b>32</b> that can be processed using the blancher <b>20</b> includes food product <b>32</b> in pouches that are preferably constructed of a flexible, synthetic material that typically is of laminate construction. Examples of such pouched food product include: sauces, soups, juices, catsup, fruits, certain pastas, vegetables, meats, hot dogs, and the like. Food products <b>32</b> that can be processed using the blancher <b>20</b> include food products <b>32</b> not in pouches. For example, and without limitation, pastas and vegetables like potatoes, corn, rice, beans, spinach, are but a few types of food products <b>32</b> not in pouches that can be heated, cooked or blanched by the blancher <b>20</b> of this invention.

0113In operation, food products <b>32</b> are introduced into the blancher <b>20</b> through the inlet <b>60</b> and preferably enter the drum <b>52</b>. The food product transport mechanism <b>44</b> urges the food products <b>32</b> received in the blancher <b>20</b> toward the outlet <b>62</b> preferably by rotation.

0114Where the food product transport mechanism <b>44</b> is an auger <b>48</b>, the rate of rotation of the auger <b>48</b> is controlled to control the residency time of the food products <b>32</b> within the blancher <b>20</b>. For example, the auger <b>48</b> can be rotated as slow as one-half of a revolution per minute to as fast as ten or more revolutions per minute depending on factors such as 1) the type of food product <b>32</b>, 2) the length of the blancher <b>20</b>, 3) the diameter of the blancher <b>20</b>, 4) whether the food product <b>32</b> is simply being blanched or pasteurized, 5) the type of heat transfer medium <b>33</b> being used, and 6) other factors. Typically, selection of a rate of rotation is based upon experience and routine testing and experimentation.

0115As the food products <b>32</b> travel along the blancher <b>20</b>, they are immersed in the heat transfer medium <b>33</b>, which heats the food products <b>32</b>. Where the blancher <b>20</b> is equipped with baffles <b>88</b>, the baffles <b>88</b> help scoop up at least some of the food products <b>32</b> that have fallen to the bottom. As each baffle <b>88</b> rises toward the surface of the heat transfer medium <b>33</b>, typically water, food products <b>32</b> carried by the baffle <b>88</b> slide off and tumble, thereby agitating the food products <b>32</b> while also helping to break up clumps of food products <b>32</b>.

0116Where liquid injection is used, the liquid flows <b>106</b> are directed from orifices <b>94</b> toward food products <b>32</b> in the blancher <b>20</b> displacing at least some of the food products <b>32</b> which helps break up any food products <b>32</b> that have clumped together, increasing heat transfer efficiency. Additionally, the liquid flows <b>106</b> directed toward the food products <b>32</b> help agitate them thereby increasing heat transfer efficiency. Where liquid, such as water, is discharged, the volumetric flow rate and pressure are selected to satisfy the following condition: <maths id="MATH-US-00001" num="00001"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><mi>P</mi><mo>·</mo><mi>V</mi></mrow><mo>≥</mo><mrow><mn>55</mn><mo>⁢</mo><mfrac><mrow><mi>lbs</mi><mo>·</mo><mi>gallons</mi></mrow><mrow><msup><mi>in</mi><mn>2</mn></msup><mo>·</mo><mi>min</mi></mrow></mfrac></mrow></mrow></mtd><mtd><mrow><mo>(</mo><mrow><mi>Equation</mi><mo>⁢</mo><mstyle><mtext> </mtext></mstyle><mo>⁢</mo><mi>I</mi></mrow><mo>)</mo></mrow></mtd></mtr></mtable></math></maths><img file="USRE40232E_D0001.tif" />

0117where: <ul id="ul0001" list-style="none"><li id="ul0001-0001" num="0000"><ul id="ul0002" list-style="none"><li id="ul0002-0001" num="0118">P is the pressure of the liquid in psi; and</li><li id="ul0002-0002" num="0119">V is the volumetric flow rate of liquid discharged from each orifice <b>94</b> in gpm.</li></ul></li></ul>

0120Where more turbulence is desired, the volumetric flow rate and pressure are selected to provide highly turbulent flow within the blancher and satisfy the following condition: <maths id="MATH-US-00002" num="00002"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><mi>P</mi><mo>·</mo><mi>V</mi></mrow><mo>≥</mo><mrow><mn>65</mn><mo>⁢</mo><mfrac><mrow><mi>lbs</mi><mo>·</mo><mi>gallons</mi></mrow><mrow><msup><mi>in</mi><mn>2</mn></msup><mo>·</mo><mi>min</mi></mrow></mfrac></mrow></mrow></mtd><mtd><mrow><mo>(</mo><mrow><mi>Equation</mi><mo>⁢</mo><mstyle><mtext> </mtext></mstyle><mo>⁢</mo><mi>II</mi></mrow><mo>)</mo></mrow></mtd></mtr></mtable></math></maths><img file="USRE40232E_D0002.tif" />

0121Where gas injection is used, the gas flows <b>106</b> are directed from orifices <b>94</b> toward food products <b>32</b> in the blancher <b>20</b> increasing the buoyancy of at least some of the food products <b>32</b>. By increasing buoyancy, at least some of the food products <b>32</b> will float up from the bottom and thereby become more directly exposed to the heat transfer medium <b>33</b> increasing heat transfer efficiency. Depending upon the volume and pressure of gas injected, the force of the gas flows <b>106</b> impinging against food products <b>32</b> will also help agitate them which further increases heat transfer efficiency. Depending upon the force with which the gas impinges, the gas flows <b>106</b> impinging against food products <b>32</b> can also help break up clumps of food products. Where a gas, such as air, is discharged, the flow rate and pressure are selected to provide highly turbulent flow within the blancher and to satisfy the following condition: <maths id="MATH-US-00003" num="00003"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><mi>P</mi><mo>·</mo><mi>V</mi></mrow><mo>≥</mo><mrow><mn>0.1275</mn><mo>⁢</mo><mfrac><mrow><mi>in</mi><mo>⁢</mo><mstyle><mtext> </mtext></mstyle><mo>⁢</mo><mi>of</mi><mo>⁢</mo><mstyle><mtext> </mtext></mstyle><mo>⁢</mo><msub><mi>H</mi><mn>2</mn></msub><mo>⁢</mo><mi>O</mi></mrow><mi>CFM</mi></mfrac></mrow></mrow></mtd><mtd><mrow><mo>(</mo><mrow><mi>Equation</mi><mo>⁢</mo><mstyle><mtext> </mtext></mstyle><mo>⁢</mo><mi>III</mi></mrow><mo>)</mo></mrow></mtd></mtr></mtable></math></maths><img file="USRE40232E_D0003.tif" />

0122where: <ul id="ul0003" list-style="none"><li id="ul0003-0001" num="0000"><ul id="ul0004" list-style="none"><li id="ul0004-0001" num="0123">P is the pressure of the gas in inches of H₂O; and</li><li id="ul0004-0002" num="0124">V is the volumetric flow rate of gas discharged from each orifice <b>94</b> in CFM.</li></ul></li></ul>

0125Where even more flow and turbulence are desired, the gas flow rate and pressure are selected to satisfy the following condition: <maths id="MATH-US-00004" num="00004"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><mi>P</mi><mo>·</mo><mi>V</mi></mrow><mo>≥</mo><mrow><mn>0.15</mn><mo>⁢</mo><mfrac><mrow><mi>in</mi><mo>⁢</mo><mstyle><mtext> </mtext></mstyle><mo>⁢</mo><mi>of</mi><mo>⁢</mo><mstyle><mtext> </mtext></mstyle><mo>⁢</mo><msub><mi>H</mi><mn>2</mn></msub><mo>⁢</mo><mi>O</mi></mrow><mi>CFM</mi></mfrac></mrow></mrow></mtd><mtd><mrow><mo>(</mo><mrow><mi>Equation</mi><mo>⁢</mo><mstyle><mtext> </mtext></mstyle><mo>⁢</mo><mi>IV</mi></mrow><mo>)</mo></mrow></mtd></mtr></mtable></math></maths><img file="USRE40232E_D0004.tif" />

0126Where steam is discharged, the flow rate and pressure are selected to provide highly turbulent flow within the blancher and satisfy the following condition: <maths id="MATH-US-00005" num="00005"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><mi>P</mi><mo>·</mo><mi>V</mi></mrow><mo>≥</mo><mrow><mn>300</mn><mo>⁢</mo><mfrac><msup><mi>lbs</mi><mn>2</mn></msup><mrow><msup><mi>in</mi><mn>2</mn></msup><mo>·</mo><mi>hr</mi></mrow></mfrac></mrow></mrow></mtd><mtd><mrow><mo>(</mo><mrow><mi>Equation</mi><mo>⁢</mo><mstyle><mtext> </mtext></mstyle><mo>⁢</mo><mi>V</mi></mrow><mo>)</mo></mrow></mtd></mtr></mtable></math></maths><img file="USRE40232E_D0005.tif" />

0127where: <ul id="ul0005" list-style="none"><li id="ul0005-0001" num="0000"><ul id="ul0006" list-style="none"><li id="ul0006-0001" num="0128">P is the pressure of the steam in pounds per square inch; and</li><li id="ul0006-0002" num="0129">V is the volumetric flow rate of steam discharged from each orifice <b>94</b> in lbs/hr.</li></ul></li></ul>

0130In some instances, it may be desirable to use gas injection alone to increase heat transfer. In other instances, it may be desirable to use gas injection in combination with baffles <b>88</b> or another direct-contact agitation device. In still other instances, it may be desirable to use a combination of gas injection and liquid injection or a combination of gas injection, liquid injection, and direct-contact agitation devices. In even other instances, it may be desirable to use liquid injection with or without direct-contact mechanical agitation devices.

0131Once food products <b>32</b> have completed their journey through the blancher <b>20</b>, they are discharged from the outlet <b>62</b>. After that, the food products <b>32</b> can be packaged and shipped, packaged and frozen, stored, or further processed.

0132It is also to be understood that, although the foregoing description and drawings describe and illustrate in detail one or more embodiments of the present invention, to those skilled in the art to which the present invention relates, the present disclosure will suggest many modifications and constructions as well as widely differing embodiments and applications without thereby departing from the spirit and scope of the invention. The present invention, therefore, is intended to be limited only by the scope of the appended claims.