US20180352818A1 - Convection oven with linear counter-flow heat exchanger - Google Patents
Convection oven with linear counter-flow heat exchanger Download PDFInfo
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- US20180352818A1 US20180352818A1 US16/053,552 US201816053552A US2018352818A1 US 20180352818 A1 US20180352818 A1 US 20180352818A1 US 201816053552 A US201816053552 A US 201816053552A US 2018352818 A1 US2018352818 A1 US 2018352818A1
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- duct
- heat transfer
- linear
- duct portion
- convection oven
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- A—HUMAN NECESSITIES
- A21—BAKING; EDIBLE DOUGHS
- A21B—BAKERS' OVENS; MACHINES OR EQUIPMENT FOR BAKING
- A21B1/00—Bakers' ovens
- A21B1/02—Bakers' ovens characterised by the heating arrangements
- A21B1/24—Ovens heated by media flowing therethrough
- A21B1/26—Ovens heated by media flowing therethrough by hot air
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- A—HUMAN NECESSITIES
- A21—BAKING; EDIBLE DOUGHS
- A21B—BAKERS' OVENS; MACHINES OR EQUIPMENT FOR BAKING
- A21B1/00—Bakers' ovens
- A21B1/42—Bakers' ovens characterised by the baking surfaces moving during the baking
- A21B1/44—Bakers' ovens characterised by the baking surfaces moving during the baking with surfaces rotating in a horizontal plane
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- A—HUMAN NECESSITIES
- A21—BAKING; EDIBLE DOUGHS
- A21B—BAKERS' OVENS; MACHINES OR EQUIPMENT FOR BAKING
- A21B3/00—Parts or accessories of ovens
- A21B3/04—Air-treatment devices for ovens, e.g. regulating humidity
Abstract
A convection oven includes a cooking chamber for cooking a food product, an air circulator that circulates process air in a first direction through the cooking chamber and along a circulation path in a circulation passage. A heat exchanger includes one or more heat transfer ducts longitudinally arranged along the circulation path. One or more heating elements heat a fluid that is circulated in a second direction through the one or more heat transfer ducts which is opposite to the first direction. The process air absorbs heat from the heated fluid as the process air travels along the circulation path back to the cooking chamber. A partition wall may separate first and second parallel portions of the one or more heat transfer ducts. A heat exchanger may preheat fluid entering the one or more heat transfer ducts using heated fluid leaving the heat transfer ducts.
Description
- This application is a continuation of U.S. patent application Ser. No. 15/012,710, filed on Feb. 1, 2016, which claims priority to U.S. Provisional Patent Application No. 62/111,577, filed Feb. 3, 2015, the entirety of which is incorporated herein by reference.
- The current invention relates to convection ovens that circulate heated air through a cooking chamber.
- Convection ovens circulate heated air in a cooking chamber to distribute heated process air evenly around food product. Some convection ovens generate heat using a flame element. Previously implemented convection ovens using the flame element are typically one of two types: direct-fired or indirect-fired. In direct-fired ovens, the products of combustion produced by the flame element may be vented directly into the process airflow and come in contact with the food in the cooking chamber. In indirect-fired ovens, the products of combustion may be separated from the process airflow and do not contact the food in the cooking chamber. Indirect firing of a convection oven may be preferred in ovens where control of the amount of moisture in the airflow is critical to the quality of the cooking process. The addition of combustion exhaust by a direct-fired method may increase or decrease moisture content and thereby alter the baking or cooking process.
- There is an inherent inefficiency in any fuel-fired process due to the need for oxygen in the combustion process. Oxygen is nearly always supplied by ambient air, which may be at or around ambient temperature. A portion of the energy supplied by the fuel is utilized to heat the oxygen and the associated air, which is mostly inert in the combustion process. Inefficiency is compounded when the process temperatures are elevated, such as in baking and cooking ovens where the process air may be between 150° C. and 250° C. above ambient temperature. In such cases, inefficiency is at least partially a result of the energy required to heat air used for combustion from ambient temperature to a temperature above the desired cooking process temperature.
- Previously implemented solutions have addressed the issue of combustion inefficiency by improving the effectiveness of the heat transfer from the combustion process to the process air. Some solutions have used “crossflow” where the flame, products of combustion and exhaust are ducted transversely to the flow of process air to increase the heat transfer efficiency. Other solutions have used “cross counter-flow” where the flow of flame, products of combustion and exhaust are ducted transversely to the flow of process air in successive passes progressing in a direction counter to the flow of process air. Although the previously implemented solutions have achieved some degree of success, they have failed to fully overcome the physical limitations of space within the conventional size of an oven and the associated cost and difficulty of construction.
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FIG. 1 illustrates a cross-sectional front side view of a convection oven according to a first embodiment. -
FIG. 2 illustrates a perspective view of the convection oven ofFIG. 1 . -
FIG. 3 illustrates a cross-sectional perspective view of the convection oven ofFIG. 1 . -
FIG. 4 illustrates a first enlarged cross-sectional perspective view of a heat exchanger housing of the convection oven ofFIG. 1 . -
FIG. 5 illustrates a first cross-sectional left side view of the convection oven ofFIG. 1 . -
FIG. 6 illustrates a second cross-sectional perspective view of a heat exchanger housing of the convection oven ofFIG. 1 . -
FIG. 7 illustrates a second cross-sectional left side view of the convection oven ofFIG. 1 . -
FIG. 8 illustrates a cross-sectional front side view of a convection oven according to a second embodiment. -
FIG. 9 illustrates a cross-sectional front side view of a convection oven according to a third embodiment. - In convection ovens, the process of heat transfer to the product (often a food product) is by means of convection; the movement of process air A within the oven chamber. The process air A may be heated by various means, including electric heating elements, one or more direct firing burners, or indirectly using a heat exchanger. This application relates to an indirect-fired convection oven and method of distributing heat utilizing a heat exchanger for heating the process air A circulating therein. Transferring heat energy into a food product in a convection oven may be accomplished in a more efficient manner using the convection oven and methods described herein than by previously implemented solutions.
- The instant convection oven and methods advance the process of heat transfer over previously implemented solutions by using linear counter-flow, a method not previously employed in convection ovens. In the linear counter-flow method, the flow of heat (e.g., heated fluid F, products of combustion in the heat exchange ducts) is parallel to the flow of process air A (linear), but the flow of heat is in an opposite direction (counter-flow) to the direction in which the process air A flows. This method maximizes the benefits of counter-flow heat exchange.
- According to the convection oven disclosed herein, a single heat element (e.g., burner) per heat exchange duct may enhance the benefits over other previously used methods. For example, the single heat element per heat exchange duct of the instant convection oven limits the structural stresses inherent in existing heat exchangers where a single heat element feeds the products of combustion to multiple heat exchange ducts. The previously-implemented single burner to multiple duct heat exchangers typically apply the products of combustion at high temperature onto the materials that form the distribution means to the multiple heat exchange ducts, often referred to as the “duct plate.” In contrast, the one-burner-per-duct heat exchanger disclosed herein does not impinge products of combustion on a duct plate and thereby eliminates the structural stress inherent in previous designs.
- The linear counter-flow design also efficiently uses space, since the heat exchange duct(s) follow the path of process air A flow, rather than crossing the process air A flow path. In the previous cross counter-flow designs, the heat exchange duct(s) turn in the process air A flow path, either by bending or by means of collection and distribution ducts; both requiring additional space in the convection oven.
- A
convection oven 10 according to a first embodiment is shown inFIG. 1 . Theconvection oven 10 has acooking chamber 12 forcooking food product 14. Thecooking chamber 12 may be sized and shaped to accommodate arack 16 for holding thefood product 14 during cooking. A door 11 (seeFIG. 2 ) on a front of theconvection oven 10 may be selectively opened or closed to insert therack 16. Acontrol panel 13 may be provided on an exterior surface of theconvection oven 10 to control various aspects of a cooking process, such as cooking temperature, cooking time, convection characteristics, and rotation of therack 16, for example. When theconvection oven 10 is activated, the convection oven may circulate heated process air A through thecooking chamber 12 to cook thefood product 14. The heated process air A enters aprocess air entrance 18 of thecooking chamber 12, contacts thefood product 14, and then exits the cooking chamber through aprocess air exit 20. The process air A moves along a circulation path in acirculation passage 22 connecting theprocess air exit 20 toward theprocess air entrance 18. Anair circulator 24 positioned along thecirculation passage 22 moves the process air A in a first direction along the circulation path from theprocess air exit 20 to theprocess air entrance 18. - A
heat exchanger 26 heats the process air A in thecirculation passage 22 as the process air moves along the circulation path. Theheat exchanger 26 has one or moreheat transfer ducts 28 that extend longitudinally along and substantially in parallel with a length of the circulation path in thecirculation passage 22. The one or moreheat transfer ducts 28 are vertically oriented in theconvection oven 10. The one or moreheat transfer ducts 28 may be comprised of a material with a relatively high thermal conductivity, such as copper or aluminum. - The first direction is defined as the direction in which the process air A moves along the circulation path through the
circulation passage 22 from theprocess air exit 20 to the process air entrance. In the present embodiment, for example, the first direction is initially downward and substantially in parallel to apartition wall 42 in afirst passage portion 22A of thecirculation passage 22. The first direction then bends around a distal end of thepartition wall 42. In asecond passage portion 22B of thecirculation passage 22, the first direction is an upward direction and substantially in parallel to the partition wall. The first direction changes to a horizontal direction near the top of theconvection oven 10, then changes to a direction following a flow path through theair circulator 24. After the process air A exits theair circulator 24, the first direction is the horizontal direction, then the first direction changes to a downward direction before the process air A enters theprocess air entrance 18. The first direction may be different in other embodiments depending on the circulation path of the process air A through thecirculation passage 22. - One or
more heating elements 30 heat a fluid that is circulated through eachheat transfer duct 28 in a second direction defined as being opposite to the first direction in which the process air A is moving. In particular, the heated fluid F is circulated from theheating element 30 into aduct inlet 32 at a first end of eachheat transfer duct 28. Eachheat transfer duct 28 is separately sealed from thecirculation passage 22 so that the heated fluid F does not directly contact the process air A circulating along the circulation path or process air A in thecooking chamber 12. The heated fluid F moves through eachheat transfer duct 28 substantially in parallel with process air A moving in the first direction along the circulation path. The heated fluid F travels along the entire length of eachheat transfer duct 28 and exits from aduct outlet 34 at a second end of each heat transfer duct opposite the first end. - The second direction is defined as the direction in which the heated fluid F flows in the one or more
heat exchange ducts 28 exposed in thecirculation passage 22 from theduct inlet 32 to theduct outlet 34. In the present embodiment, the second direction is initially downward through thesecond passage portion 22B. The second direction then bends around the distal end of thepartition wall 42. The second direction changes to an upward direction through thefirst passage portion 22A. The second direction may be different in other embodiments depending on the circulation path of the process air A through thecirculation passage 22. - As the heated fluid F moves in the second direction, heat from the heated fluid F is conducted through walls of the one or more
heat transfer ducts 28. An outer wall along substantially the entire length of eachheat transfer duct 28 is exposed to the process air A. The process air A moving along the circulation path contacts the exposed outer wall of eachheat transfer duct 28 and absorbs heat therefrom. The linear counter-flow arrangement of the heated fluid F in theheat transfer duct 28 allows the process air A to absorb more heat than in previously implemented convection ovens, and also exhibits improved heat transfer efficiency over previously implemented convection ovens. - Heat transfer efficiency in an indirect-fired convection oven is, at least in part, a function of the difference in temperature between the heated fluid F in the
heat exchanger 26 and the process air A in the circulation passage 22: the greater the temperature difference between the heated fluid F and the process air A, the greater the amount of heat transferred from the heated fluid F to the process air A. A greater temperature difference between the process air A and the heated fluid F is maintained along the length of the one or more heat transfer ducts in the linear counter-flow design than in previously-implemented designs because the temperature of the process air A and the temperature of the heated fluid F both increase in the first direction. That is, the temperature of the heated fluid F in theheat transfer ducts 28 is the greatest at theduct inlet 32 and decreases the farther away the heated fluid F travels from the one or more heating elements 30 (i.e., temperature decreases as the heated fluid F travels in the second direction). Conversely, the temperature of the process air A is at its lowest along the circulation path when exiting theprocess air exit 20 of thecooking chamber 12, and increases as the process air A travels in the first direction along the length of the one or moreheat transfer ducts 28. The linear counter-flow design achieves improved heat transfer efficiency while maximizing available space in a convection oven. - When there are more than one
heat exchange ducts 28, the heat exchange ducts extend in parallel to each other along thecirculation passage 22, as shown inFIGS. 3, 4, and 5 . Theheat exchange ducts 28 are vertically oriented in thecirculation passage 22 and arranged from the front to the back of theconvection oven 10. Adjacentheat exchange ducts 28 are spaced apart by a gap 35 (seeFIG. 5 ) so that the process air A may contact the entire surface area of the heat exchange ducts exposed in thecirculation passage 22. In some embodiments, theheat exchange ducts 28 may be successively arranged from the front to the back of theconvection oven 10 withoutgaps 35 separating theheat exchange ducts 28. Theheat exchange ducts 28 may have different orientations or arrangements than those inconvection oven 10, as described below. - The one or
more heating elements 30 may each include a heat source for creating the heated fluid F. In the present embodiment, each of the one ormore heating elements 30 may be a burner that generates a flame for igniting a flammable fluid supplied from afluid supply manifold 36. Each of the one ormore heating elements 30 is adjacent to another of the heating elements such that ignition of one of the heating elements may ignite an adjacent one of the heating elements. Ignition of one of theheating elements 30 may therefore sequentially ignite the remaining heating elements. - A
fluid supply port 38 may be provided for and aligned with a corresponding one of the one ormore heating elements 30, as shown inFIGS. 4 and 5 . Each of the one ormore heating elements 30 may be aligned to supply the heated fluid F in a correspondingduct inlet 32 of eachheat transfer duct 28. The flammable fluid may be propelled through thefluid supply manifold 36 and expelled from thesupply ports 38 using positive pressure (seeFIGS. 4 and 6 ). The flammable fluid is then ignited by the one ormore heating elements 30 and projected at least partially as the heated fluid F into theduct inlet 32 of each of theheat transfer ducts 28. - In the present embodiment, the flammable fluid is a flammable gas, such as propane or butane, which is combusted to produce flame or exhaust (“product of combustion”) which comprises the heated fluid F. The heated fluid F may be propelled through the entire length of the
heat transfer ducts 28 using afluid circulator 40. Thefluid circulator 40 of the present embodiment comprises an exhaust blower or fan connected to aduct outlet 34 side of eachheat transfer duct 28 to help draw or pull the heated fluid F therethrough, as shown inFIGS. 4 and 6 . In some embodiments, a pump or blower may be provided on aduct inlet 32 side of eachheat transfer duct 28, or even in each heat transfer duct itself, to help convey the heated fluid F in the second direction and out of eachduct outlet 34. The heated fluid F may be conveyed through eachheat transfer duct 28 without using an active fluid circulation element using the positive pressure exerted on the heated fluid F or as a result of natural draft of the heated fluid F itself. - Other fluids and associated systems may be used instead of or in addition to the flammable gas system described above. The heated fluid F may comprise a flammable liquid that is injected through the
fluid supply manifold 36 or injected from thesupply ports 38 onto theheating elements 30, by way of non-limiting example. In some embodiments, the one ormore heating elements 30 may comprise an electric or inductive heating element that heats a non-flammable fluid that is then conveyed through eachheat transfer duct 28 in the second direction. Those of ordinary skill in the art will appreciate that there are many systems and fluids that may be implemented to move heated fluid F through eachheat transfer duct 28 without departing from the scope of the convection oven described herein. - The
air circulator 24 circulates the process air A through thecooking chamber 12 from theprocess air entrance 18 toward theprocess air exit 20. Theair circulator 24 circulates the process air A out of theprocess air exit 20 and into thecirculation passage 22. Theair circulator 24 of the present embodiment is positioned downstream of the one or moreheat transfer ducts 28 along the circulation path. Theair circulator 24 includes amotor 43 that drives acirculation element 44 about a motor shaft. Thecirculation element 44 in the present embodiment is a centrifugal fan that accelerates and expels air in a radial direction. Theair circulator 24 may have adifferent circulation element 44 in other embodiments, such as a mechanical fan that accelerates and expels air in an axial direction of rotation, by way of non-limiting example. - The
air circulator 24 moves the process air A along the circulation path in thecirculation chamber 22 in the first direction from theprocess air exit 20 and toward theprocess air entrance 18. As the process air A moves along the first direction in thecirculation passage 22, the process air A contacts and absorbs heat from the length of theheat transfer duct 28 exposed in thecirculation passage 22 between theprocess air exit 20 and theprocess air entrance 18. Afirst duct portion 28A of the one or moreheat transfer ducts 28 is closer to theprocess air entrance 18 along the circulation path than asecond duct portion 28B of the one or moreheat transfer ducts 28, which is closer to theprocess air exit 20 along the circulation path. Theprocess air exit 20 in the present embodiment is located near the top of thecooking chamber 12 and adjacent to thesecond duct portion 28B. The process air A exiting theprocess air exit 20 first contacts thesecond duct portion 28B and then thefirst duct portion 28A as the process air A moves in the first direction. - In the present embodiment, the
partition wall 42 separates thefirst duct portion 28A of eachheat transfer duct 28 and thesecond duct portion 28B in thecirculation passage 22, as shown inFIGS. 1 and 3 . Thepartition wall 42 extends substantially in parallel with thefirst duct portion 28A and thesecond duct portion 28B. Eachheat transfer duct 28 may have a U-shape or a hairpin-like shape formed with a bent duct portion 28C bending around the distal end of thepartition wall 42, which makes the transition of the heated fluid F from thefirst duct portion 28A to thesecond duct portion 28B. Thepartition wall 42 permits creation of an elongated circulation path of the process air A to increase the length and surface area of eachheat transfer duct 28 to which the process air A is exposed while traveling along the circulation path and to maximize the amount of heat that the process air absorbs from each heat transfer duct. Eachheat transfer duct 28 may additionally include a third duct portion 28D transversely extending through aninternal wall 45 and through thecirculation passage 22 downstream of thefirst duct portion 28A in the first direction to provide a return path for the heated fluid F (seeFIG. 1 ). Alternatively, eachsecond duct portion 28B may terminate at theduct outlet 34 without extending through theinternal wall 45. For example, eachsecond duct portion 28B may bend and extend into a front or a rear wall of theconvection oven 12 near theprocess air exit 20. - The process air A exiting the
process air exit 20 near the top of thecooking chamber 12 first contacts and absorbs heat along the length of thesecond duct portion 28B. The process air A then absorbs heat from the bent duct portion 28C while traveling around the lower end of thepartition wall 42 before contacting and absorbing heat along the length of thefirst duct portion 28A. Exposing the process air A to the length of the first andsecond duct portions heat transfer duct 28 while efficiently utilizing the available space in theconvection oven 10. The heated process air A flows through theair circulator 24, through the remainingcirculation passage 22, and back into thecooking chamber 12 throughprocess air entrance 18. After the heated process air A circulates through thecooking chamber 12 to heat thefood product 14, the heated process air A again exits thecooking chamber 12 from theprocess air exit 20 and begins traveling along the circulation path through thecirculation passage 22 again. - A
heat exchanger housing 46 may be positioned at both ends of the one or moreheat transfer ducts 28, as shown inFIGS. 1, 3, 4, and 6 . Theheat exchanger housing 46 has alower wall 46L having one or more pairs of adjacent apertures for respectively receiving each end of the one or moreheat transfer ducts 28. Each pair of adjacent apertures may be closely positioned to each other along the same plane on thelower wall 46L, as shown inFIGS. 1 and 6 . The pairs of adjacent apertures are successively arranged from the front to the back of theconvection oven 12 to achieve a desired width of thegaps 35. The ends of the one or moreheat transfer ducts 28 are closely positioned to provide a compact design that reduces the cost and overall size of theconvection oven 10. Thelower wall 46L of theheat exchanger housing 46 forms a seal around the one or moreheat transfer ducts 28 to help prevent fluid communication between process air A in thecirculation passage 22 and heated fluid F in the interior of theheat exchanger housing 46. In the present embodiment, theduct inlet 32 and theduct outlet 34 are positioned above thelower wall 46L of theheat exchanger housing 46, but theduct inlet 32 or theduct outlet 34 may be instead be positioned at thelower wall 46L in other embodiments. - The
heat exchanger assembly 46 includes one or morefluid intake ports 48 for receiving the fluid that is heated by the one ormore heating elements 30, as shown inFIGS. 4 and 6 . The fluid may flow through anintake cavity 50 in an interior of theheat exchanger assembly 46 to reach the one ormore heating elements 30 after entering the one or morefluid intake ports 48. The heated fluid F heated by the one ormore heating elements 30 enters into theduct inlet 32 of the one or moreheat transfer ducts 28. In the present embodiment, the one ormore heating elements 30 produce a flame that heats air received through the one or morefluid intake ports 48. Air from the one or morefluid intake ports 48 may be drawn into aheating element assembly 52 having walls that at least partially encloses the one ormore heating elements 30. Air may be drawn into theheating element assembly 52 through one or morefirst ventilation apertures 54A arranged along one or more upper walls of theheating element assembly 52 and combine with the flammable fluid from thesupply ports 38 to create an appropriate mixture for igniting the heating element flame(s). Thefirst ventilation apertures 54A orsecond ventilation apertures 54B may be consecutively arranged in one or more rows. The heating element flame(s) may heat air drawn into one or moresecond ventilation apertures 54B arranged along one or more lower walls of theheating element assembly 52. The product of combustion (e.g., the air from the one or morefluid intake ports 48, the flame, and flame exhaust) flows enters theduct inlet 32 and circulates through the one ormore heating ducts 28. In other embodiments, theheating exchanger assembly 46 may be provided without aheating element assembly 52. - A collecting
bin 56 may be positioned at or near theduct outlet 34 of the one or moreheat transfer ducts 28 to collect the heated fluid F exiting from the one or moreheat exchange ducts 28, as shown inFIGS. 4 and 6 . The collectingbin 56 includesbin walls 58 enclosing a collectingcavity 60. One or more of thebin walls 58 may form an interface that separates and seals the heated fluid F in the collectingcavity 60 from the fluid in theintake cavity 50. Theinterfacing bin walls 58 may be comprised of a material having relatively high heat conductivity, such as aluminum or copper. The heated fluid F flows out of theduct outlet 34 and collects in the collectingcavity 60 after circulating through the entire length of the one or moreheat transfer ducts 28. Heat from the heated fluid F collected in the collectingcavity 60 is absorbed by and conducted through thebin walls 58. The fluid in theintake cavity 50 flows along the interface formed by thebin walls 58 on the sides, top, bottom, front, or back of the collectingbin 56. Heat emanating from the bin walls preheats the fluid in theintake cavity 50 before the fluid enters theheating element assembly 52 or interacts with the one ormore heating elements 30. This pre-combustion heat transfer from heated fluid F in the collectingbin 56 to fluid in theintake cavity 50 significantly reduces the energy consumed in the combustion process by recovering heat that would be otherwise lost in other designs. The pre-combustion heat transfer may also effectively combust fluids at temperatures below the process air A temperature thereby reducing thermal stresses and the and overall energy required to cookfood products 14 in thecooking chamber 12. - In the present embodiment, the
heat exchanger 26 heats gas (e.g., ambient air) drawn in from theintake ports 48, but theheat exchanger 26 may heat a liquid in other embodiments. By way of non-limiting example, liquid (e.g., water, oil) may be circulated into theintake cavity 50 and heated by a flame produced by the one ormore heating elements 30 before or as the liquid flows into the one or moreheat transfer ducts 28. Alternatively, each of the one ormore heating elements 30 may include an electric or inductive heating element that heats the liquid flowing into the one or moreheat transfer ducts 28. The liquid may be pumped in from an external source or circulated through an external tank connected to the convection oven. The fluid leaving theoutlet duct 34 may be expelled from anoutlet port 62 of theheat exchange housing 46. In the present embodiment, thefluid circulator 40 is an exhaust blower that helps to expel the product of combustion from theheat exchange housing 46. - A
thermal mass 64 may be arranged adjacent to the one or moreheat transfer ducts 28 in thecirculation passage 22, as shown inFIGS. 1, 3, 8, and 9 . Thethermal mass 64 is arranged near or adjacent to theprocess air exit 20 to draw heat from the process air A exiting thecooking chamber 12 before the process air is significantly heated by the one or moreheat exchange ducts 28. Thethermal mass 64 may be used to generate steam for assisting in the cooking process and to reduce the temperature of the process air A before the process air contacts much of the one or moreheat transfer ducts 28. Thethermal mass 64 is positioned to draw heat from the process air A leaving thecooking chamber 12 so that process air A initially contacting the one or moreheat transfer ducts 28 near theprocess air exit 20 is at the lowest temperature in the circulation path. Thethermal mass 64 may effectively produce steam even at the lowest temperature in the circulation path because water may evaporate at temperatures below the temperature of the process air A entering theprocess air entrance 18 of thecooking chamber 12. The position of thethermal mass 64 increases the efficiency of theconvection oven 10 because the thermal mass may draw heat from the one or moreheat transfer ducts 28 even if the temperature of the thermal mass is lower than the temperature required to cook thefood product 14. - The
thermal mass 64 may be arranged in parallel to the one or moreheat exchange ducts 28 along the circulation path in thecirculation passage 22. Thethermal mass 64 may comprise one or more rows of bars or rods each extending between a front side and a back side of theconvection oven 10, as shown inFIG. 7 . One ormore sprayers 66 may spray water onto thethermal mass 64 to generate steam in thecirculation passage 22. The one ormore sprayers 66 may be located above or upstream of thethermal mass 64 in the circulation path of thecirculation passage 22 to help evenly distribute the water over the thermal mass. - The
convection oven 10 may include a rack rotating device 67 (seeFIGS. 1 and 2 ) positioned above therack 16 and configured to rotate the rack in thecooking chamber 12. Therack rotating device 67 includes amotor 68 that rotates a downwardly extendingshaft 69. Theshaft 69 rotates therack 16 during a cooking process to promote even distribution of the heated process air A over thefood product 14. A distal end of theshaft 69 may engage with therack 16 using an attachment feature to allow the rack to rotate with the shaft. The attachment feature may be a formed shape, channel or plate affixed to theshaft 69 that interlocks with formed shapes or channels affixed to the top of therack 16. In some embodiments, therack rotating device 67 may attach to and lift therack 16 upwards using a flange disposed near the distal end of theshaft 69. The flange on the distal end may engage underneath a portion of therack 16 to help lift therack 16. The attachment feature is not particularly limited and may be any feature known by those of ordinary skill in the art, including a clamp, a hook, or a loop, by way of further non-limiting example. Thecontrol panel 13 may be operated to control operation aspects of therack rotating device 67, such as lift, rotation speed, and rotation duration, for example. - The
convection oven 10 may have a different heat exchanger configuration than theheat exchanger 26 shown inFIGS. 1 and 3 . In another embodiment, aconvection oven 70 is provided with one or moreheat transfer ducts 68 linearly extending through thecirculation passage 22 and which do not have a U-shape or hairpin-like shape, as shown inFIG. 8 . The process air A exits through aprocess air exit 74 located near the bottom of thecooking chamber 12. The process air A moves in a first direction (i.e., upward) along the axial length of one or moreheat transfer ducts 68. The heated fluid F enters theduct inlet 32 and travels through the one or moreheat transfer ducts 68 in a second direction opposite to the first direction (i.e., downward). The one or moreheat transfer ducts 68 heat the process air A moving along the circulation path in thecirculation passage 22. The one or moreheat transfer ducts 68 are arranged in parallel to one another and extend substantially in parallel to the circulation path in thecirculation passage 22. - The heated fluid F exits from the
duct outlet 34 at an end of the one or moreheat transfer ducts 68 opposite theduct inlet 32. Theduct outlet 34 may be connected to anoutlet assembly 76 for disposing of or recycling the heated fluid F. The one or moreheat transfer ducts 68 may bend in thecirculation passage 22 to convey the heated fluid F through anexterior wall 78 of theconvection oven 10 and into theoutlet assembly 76. Alternatively, theoutlet assembly 76 may be provided at least partially in thecirculation passage 22 to receive heated fluid F exiting the one or moreheat transfer ducts 68. - In a further embodiment, a
convection oven 80 may have aheat exchanger 82 adjacent to theprocess air entrance 18 of thecooking chamber 12, as shown inFIG. 9 . Theprocess air entrance 18 may be provided near the one or moreheat transfer ducts 84 extend linearly and substantially in parallel to the circulation path of the process air A in thecirculation passage 22. The process air A is circulated along the circulation path in thecirculation passage 22 in the first direction from theprocess air exit 20 toward theprocess air entrance 18 disposed near the bottom of theconvection oven 80. Theair circulator 24 in theconvection oven 80 is disposed upstream of the one or moreheat transfer ducts 84 along the circulation path. After the process air A circulates through theair circulator 24, the process air A moves in a first direction (i.e., downward) toward theprocess air entrance 18 near the bottom of thecooking chamber 12. The heated fluid F flows into eachduct inlet 32 and through the one or moreheat transfer ducts 84 in the second direction opposite to the first direction (i.e., upward in a counter-flow direction). The linearly extendingheat transfer ducts 84 do not have a U-shape or hairpin-like shape. - The one or
more heating elements 30 are mounted near the bottom of theconvection oven 80. In the present embodiment, the one ormore heating elements 30 are vertically oriented and disposed in thecirculation passage 22. In some embodiments, the one ormore heating elements 30 may be horizontally oriented and disposed in or extending through aside wall 86 of theconvection oven 80. In further embodiments, the one or moreheat transfer ducts 84 may extend through apertures on the side wall and connect to the one ormore heating elements 30 disposed on an exterior surface of theside wall 86. When the one ormore heating elements 30 are not vertically oriented, each of the one or moreheat transfer ducts 84 may have a bent portion near the bottom of theconvection oven 80 to connect eachduct inlet 32 to a respective one of theheating elements 30. - The heated fluid F flows in the second direction through the one or more
heat transfer ducts 84 and exits through theduct outlet 34 near the top of theconvection oven 80. Theduct outlet 34 may be connected to anoutlet assembly 88 near the top of theconvection oven 80. In the present embodiment, theduct outlet 34 is connected to theoutlet assembly 88 in thecirculation passage 22. In other embodiments, the one or moreheat transfer ducts 84 may extend through anupper wall 90 or upper portion of theside wall 86 to connect theduct outlet 34 to theoutlet assembly 88 disposed outside of thecirculation passage 22. - A
thermal mass 92 is adjacent to the one or moreheat transfer ducts 84 near the top of theconvection oven 80 in thecirculation passage 22. Thethermal mass 92 helps to draw heat from the process air A before the process air A is significantly heated by the one or moreheat transfer ducts 84. Thethermal mass 92 may be used to generate steam for assisting in the cooking process and to reduce the temperature of the process air A before the process air A contacts the one or moreheat transfer ducts 84. Thethermal mass 92 may have a substantially identical configuration to thethermal mass 64 in other respects. Thethermal mass 92 increases the efficiency of theconvection oven 80 in a similar manner as thethermal mass 64 in theconvection oven 10. One ormore sprayers 94 may be provided adjacent to thethermal mass 92 to spray water onto thethermal mass 92 to generate steam in thecirculation passage 22. - Other configurations of a convection oven may be implemented without departing from the scope of the linear counter-flow design described herein. By way of non-limiting example, one or more heat transfer ducts may be horizontally oriented in a portion of the
circulation passage 22 above thecooking chamber 12 of a convection oven. Alternatively, the one or moreheat transfer ducts 28/68/84 may be L-shaped with a first vertically oriented portion adjacent to theprocess air entrance 18 or the process air A exit, and a second horizontally oriented portion in a portion of the circulation passage above the cooking chamber. Theheat exchanger 26 andpartition wall 42 of theconvection oven 10 may be disposed on aprocess air entrance 18 side of thecirculation passage 22 instead of on aprocess air exit 20 side of the circulation passage. - Various embodiments of the invention are described above in the detailed description. While these descriptions directly describe the above embodiments, it is understood that those skilled in the art may conceive modifications and/or variations to the specific embodiments shown and described herein. Any such modifications or variations that fall within the purview of this description are intended to be included therein as well. Unless specifically noted, it is the intention of the inventor that the words and phrases in the specification and claims be given the ordinary and accustomed meanings to those of ordinary skill in the applicable art(s).
- The foregoing description of various embodiments of the invention known to the applicant at the time of filing the application has been presented and is intended for the purposes of illustration and description. The present description is not intended to be exhaustive nor limit the invention to the precise form disclosed and many modifications and variations are possible in the light of the above teachings. The embodiments described serve to explain the principles of the invention and its practical application and to enable others skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed for carrying out the invention.
- While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention. It will be understood by those within the art that, in general, terms used herein are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.).
Claims (57)
1. A convection oven comprising:
a cooking chamber having a process air entrance and a process air exit;
a circulation passage connecting the process air entrance and the process air exit;
an air circulator configured to move process air along a circulation path through the circulation passage in a first direction from the process air exit to the process air entrance, and configured to circulate process air through the cooking chamber; and
a heat exchanger including a plurality of heat transfer ducts longitudinally arranged in the circulation passage along the circulation path, each of the plurality of heat transfer ducts being separately sealed from the cooking chamber and the circulation passage, one or more heating elements configured to heat a fluid provided to a duct input end portion of each of the plurality of heat transfer ducts, the heat exchanger configured to move the heated fluid through the plurality of heat transfer ducts in a second direction opposite to the first direction, each of the plurality of heat transfer ducts including a duct output end portion terminating at a duct outlet from which the heated fluid is removed from the heat transfer duct, the duct output end portion being positioned downstream in the first direction of the duct input end portion in the circulation path.
2. The convection oven of claim 1 , wherein each of the plurality of heat transfer ducts is spaced apart from each of the others of the plurality of heat transfer ducts.
3. The convection oven of claim 1 , wherein each of the plurality of heat transfer ducts includes a bent portion disposed between and connecting a first duct portion of the heat transfer duct and a second duct portion of the heat transfer duct, the second duct portion being closer to the process air exit along the circulation path than the first duct portion.
4. The convection oven of claim 1 , wherein each of the plurality of heat transfer ducts includes a linear first duct portion comprising at least a majority of the overall length of the heat transfer duct.
5. The convection oven of claim 1 , wherein each of the plurality of heat transfer ducts includes a linear first duct portion positioned to receive the heated fluid from the duct input end portion, a linear second duct portion positioned to provide the heated fluid to the duct output end portion, and a bent portion connecting together the linear first duct portion and the linear second duct portion for communication of the heated fluid from the linear first duct portion to the linear second duct portion.
6. The convection oven of claim 5 , wherein the linear first duct portion extends in parallel with the linear first duct portion of each of the others of the plurality of heat transfer ducts, and the linear second duct portion extends in parallel with the linear second duct portion of each of the others of the plurality of heat transfer ducts, the linear second duct portion being positioned upstream of the linear first duct portion in the first direction along the circulation path.
7. The convection oven of claim 5 , wherein the bent portion is connected to a lower end portion of the linear first duct portion and to a lower end portion of the linear second duct portion.
8. The convection oven of claim 7 , wherein the one or more heating elements are positioned at the duct input end portion and at least partially above the linear first duct portion.
9. The convection oven of claim 1 , wherein the one or more heating elements includes a different heating element for heating the fluid provided to each of the plurality of heat transfer ducts.
10. A convection oven comprising:
a cooking chamber having a process air entrance and a process air exit;
a circulation passage connecting the process air entrance and the process air exit;
an air circulator configured to move process air along a circulation path through the circulation passage in a first direction from the process air exit to the process air entrance, and configured to circulate process air through the cooking chamber; and
a heat exchanger including a plurality of heat transfer ducts longitudinally arranged in the circulation passage along the circulation path, each of the plurality of heat transfer ducts being spaced apart from the others of the plurality of heat transfer ducts, one or more heating elements configured to heat a fluid provided to each of the plurality of heat transfer ducts, the heat exchanger configured to move the heated fluid through the plurality of heat transfer ducts in a second direction opposite to the first direction.
11. The convection oven of claim 10 , wherein each of the plurality of heat transfer ducts includes a linear first duct portion, a linear second duct portion and a bent portion connecting together the linear first duct portion and the linear second duct portion for communication of the heated fluid from the linear first duct portion to the linear second duct portion.
12. The convection oven of claim 11 , wherein the linear first duct portion is positioned to receive the heated fluid heated by the one or more heating elements, the linear first duct portion extends in parallel with the linear first duct portion of each of the others of the plurality of heat transfer ducts, and the linear second duct portion extends in parallel with the linear second duct portion of each of the others of the plurality of heat transfer ducts, the linear second duct portion being positioned upstream of the linear first duct portion in the first direction along the circulation path.
13. The convection over of claim 12 , wherein the linear first duct portion is arranged parallel to and spaced apart from the linear second duct portion.
14. The convection oven of claim 11 , wherein the bent portion is connected to a lower end portion of the linear first duct portion and to a lower end portion of the linear second duct portion.
15. The convection oven of claim 14 , wherein the one or more heating elements are positioned at least partially above the linear first duct portion.
16. The convection oven of claim 10 , wherein each of the plurality of heat transfer ducts includes a third duct portion extending from the second duct portion and terminating at a duct outlet from which the heated fluid is removed from the heat transfer duct.
17. The convection oven of claim 16 , wherein the third duct portion is positioned downstream in the first direction of the first duct portion in the circulation path.
18. The convection oven of claim 10 , wherein the one or more heating elements includes a different heating element for heating the fluid provided to each of the plurality of heat transfer ducts.
19. The convection oven of claim 10 , wherein each of the plurality of heat transfer ducts includes a first duct portion and a second duct portion, the first duct portion being positioned to receive the heated fluid heated by the one or more heating elements, the first duct portion extending in parallel with the first duct portion of each of the others of the plurality of heat transfer ducts and extending along the circulation path, and the second duct portion extending in parallel with the second duct portion of each of the others of the plurality of heat transfer ducts and extending along the circulation path, the second duct portion being positioned upstream of the first duct portion in the first direction along the circulation path, and the second duct portion being spaced apart from the first duct portion.
20. The convection oven of claim 19 , wherein the first duct portion of each of the plurality of heat transfer ducts has a duct inlet to receive the fluid heated by the one or more heating elements.
21. The convection oven of claim 19 , wherein the second duct portion is located closer to the process air exit along the circulation path than the first duct portion.
22. The convection oven of claim 21 , wherein the second duct portion is positioned adjacent to the process air exit in the circulation passage.
23. The convection oven of claim 19 , wherein the first duct portion is closer to the process air entrance along the circulation path than the second duct portion.
24. The convection oven of claim 10 , wherein each of the plurality of heat transfer ducts has a duct inlet to receive the heated fluid heated by a different corresponding one of the one or more heating elements.
25. The convection oven of claim 24 , wherein each heating element of the plurality of heating elements is arranged adjacent to another of the heating elements of the plurality of heating elements such that ignition of one heating element ignites an adjacent one of the heating elements.
26. The convection oven of claim 10 , wherein each of the plurality of heat transfer ducts has a duct outlet from which the heated fluid is removed, and further comprises a fluid circulator configured to circulate the heated fluid through the plurality of heat transfer ducts, the fluid circulator being connected at the duct outlets of the plurality of heat transfer ducts.
27. The convection oven of claim 10 , wherein each of the plurality of heat transfer ducts has a duct inlet to receive the heated fluid heated by the one or more heating elements, and further comprises a fluid circulator configured to circulate the heated fluid through the plurality of heat transfer ducts, the fluid circulator being connected at the duct inlets of the plurality of heat transfer ducts.
28. The convection oven of claim 10 , wherein each of the plurality of heat transfer ducts terminates at an exhaust duct outlet from which the heated fluid is exhausted from the heat transfer duct, the exhaust duct outlet being positioned downstream in the first direction in the circulation path, and the heat exchanger further includes a fluid intake chamber arranged to receive the fluid to be heated by the one or more heating elements and a collection chamber arranged to receive and collect the exhausted heated fluid, the collection chamber being positioned to transfer heat from the heated fluid therein to the fluid in the fluid intake chamber to preheat the fluid received in the fluid intake chamber before being heated by the one or more heating elements heat.
29. The convection oven of claim 28 , wherein the collection chamber and the fluid intake chamber having a heat conductive common wall that radiates heat from the heated fluid in the collection chamber to heat the fluid in the fluid intake chamber.
30. A convection oven comprising:
a cooking chamber having a process air entrance and a process air exit;
a circulation passage connecting the process air entrance and the process air exit;
an air circulator configured to move process air along a circulation path through the circulation passage in a first direction from the process air exit to the process air entrance, and configured to circulate process air through the cooking chamber; and
a heat exchanger including a plurality of heat transfer ducts longitudinally arranged in the circulation passage along the circulation path, each of the plurality of heat transfer ducts being spaced apart from the others of the plurality of heat transfer ducts, one or more heating elements configured to heat a fluid provided to each of the plurality of heat transfer ducts, the heat exchanger configured to move the heated fluid through the plurality of heat transfer ducts in a second direction opposite to the first direction, each of the plurality of heat transfer ducts including a linear first duct portion, a linear second duct portion and a bent duct portion in fluid communication with both the linear first duct portion and the linear second duct portion.
31. The convection oven of claim 30 , wherein the linear first duct portion is positioned to receive the heated fluid heated by the one or more heating elements, the linear first duct portion extends in parallel with the linear first duct portion of each other of the plurality of heat transfer ducts, and the linear second duct portion extends in parallel with the linear second duct portion of each other of the plurality of heat transfer ducts.
32. The convection over of claim 31 , wherein the linear first duct portion is arranged parallel to and spaced apart from the linear second duct portion.
33. The convection oven of claim 30 , wherein the linear first duct portion has first and second end portions, the linear second duct portion has first and second end portions, and the bent duct portion has first and second end portions, the first end portion of the linear first duct portion being positioned to receive the heated fluid heated by the one or more heating elements, the second end portion of the linear first duct portion being connected to the first end portion of the bent portion, the first end portion of the linear second duct portion being positioned to exhaust the heated fluid, and the second end portion of the linear second duct portion being connected to the second end portion of the bent portion.
34. The convection oven of claim 33 , wherein the first end portion of the linear first duct portion is positioned above the second end portion of the linear first duct portion, and the first end portion of the linear second duct portion is positioned above the second end portion of the linear second duct portion.
35. The convection oven of claim 30 , wherein the one or more heating elements are positioned above the linear first duct portion and in fluid communication with the first linear duct portion, and the bent portion connects together lower end portions of the first and second linear duct portions.
36. The convection oven of claim 35 , further including one or more duct outlets configured to receive the heated fluid from the plurality of heat transfer ducts, and wherein the one or more duct outlets are positioned above the second linear duct portion and in fluid communication with the second linear duct portion.
37. The convection oven of claim 30 , further including one or more duct outlets configured to receive the heated fluid from the heat transfer ducts, and wherein the one or more heating elements are positioned above the linear first duct portion and in fluid communication with the linear first duct portion, the one or more duct outlets are positioned above the linear second duct portion and in fluid communication with the linear second duct portion, and the bent portion is positioned below the one or more duct outlets and the one or more heating elements and is in fluid communication with lower end portions of the linear first and second duct portions to pass the heated fluid from the linear first duct portion to the linear second duct portion.
38. The convection oven of claim 30 , further comprising a partition wall in the circulation passage, wherein the linear first duct portion is separated from the linear second duct portion by the partition wall, and the bent duct portion is positioned at a lower end of the partition wall.
39. The convection oven of claim 38 , wherein the linear first duct portions of the plurality of heat transfer ducts are positioned adjacent to a first side of the partition wall at spaced apart positions therealong, and the linear second duct portions of the plurality of heat transfer ducts are positioned adjacent to an opposite second side of the partition wall at spaced apart positions therealong.
40. The convection oven of claim 39 , wherein the linear first duct portions have an upright orientation and the linear second duct portions have an upright orientation.
41. The convection oven of claim 40 , wherein the linear first duct portions are in parallel arrangement and the linear second duct portions are in parallel arrangement.
42. A convection oven comprising:
a cooking chamber having a process air entrance and a process air exit;
a circulation passage connecting the process air entrance and the process air exit, the circulation passage having a partition wall disposed therein which terminates at a distal end to define a first passage portion and a second passage portion, the first passage portion having a first end portion and a second end portion, the second passage portion having a first end portion and a second end portion, the process air exit being in fluid communication with the first end portion of the first passage portion, the second end portion of the first passage portion being in fluid communication with the first end portion of the second passage portion, and the second end portion of the second passage portion being in fluid communication with the process air entrance, the second end portion of the first passage portion and the first end portion of the second passage portion being located at the distal end of the partition wall;
an air circulator configured to move process air along a circulation path through the circulation passage in a first direction from the process air exit to the process air entrance, and configured to circulate process air through the cooking chamber, the first direction of process air from the process air exit along the circulation path being from the first end portion of the first passage portion to the second end portion of the first passage portion, then from the second end portion of the first passage portion to the first end portion of the second passage portion, and then from the first end portion of the second passage portion to the second end portion of the second passage portion before moving to the process air entrance; and
a heat exchanger including one or more heat transfer ducts longitudinally arranged in the circulation passage along the circulation path, each of the one or more heat transfer ducts being separately sealed from the cooking chamber and the circulation passage, each of the one or more heat transfer ducts includes a first duct portion positioned within the second passage portion and a second duct portion positioned within the first passage portion, with the partition wall positioned between the first and second duct portions, one or more heating elements configured to heat a fluid provided to a duct inlet of the first duct portion of each of the one or more heat transfer ducts, the heat exchanger configured to move the heated fluid through both the first duct portion in the second passage portion and the second duct portion in the first passage portion of the one or more heat transfer ducts in a second direction opposite to the first direction.
43. The convection oven of claim 42 , wherein the first duct portion extends substantially in parallel with and along the second passage portion of the circulation path, and the second duct portion extends substantially in parallel with and along the first passage portion of the circulation path, the second duct portion being positioned upstream of the first duct portion relative to the first direction along the circulation path, and the second duct portion being spaced apart from the first duct portion.
44. The convection oven of claim 42 , wherein the heat exchanger includes a plurality of heating elements, and the heat exchanger includes a plurality of heat transfer ducts, each heat transfer duct having a duct inlet into which the heated fluid enters from a corresponding one of the plurality of heating elements.
45. The convection oven of claim 44 , wherein each heating element of the plurality of heating elements is arranged adjacent to another of the heating elements of the plurality of heating elements such that ignition of one heating element ignites an adjacent one of the heating elements.
46. The convection oven of claim 42 , wherein each of the one or more heat transfer ducts further comprises a duct outlet from which the heated fluid is removed, the duct outlet being positioned downstream relative to the first direction along the circulation path from the duct inlet.
47. The convection oven of claim 42 , further comprising a thermal mass adjacent to the one or more heat transfer ducts in the circulation passage along the circulation path, the thermal mass being configured to absorb heat from the process air in the circulation passage.
48. The convection oven of claim 47 , further comprising a liquid sprayer configured to spray liquid onto the thermal mass to generate steam when the thermal mass absorbs heat from the process air.
49. The convection oven of claim 42 , wherein the heat exchanger further includes an outlet port from which at least some of the heated fluid is removed from the heat exchanger, a collection chamber arranged between a duct outlet of the one or more heat transfer ducts and the outlet port and configured to collect the heated fluid removed from the one or more heat transfer ducts, and a fluid inlet that receives the fluid to be heated by the one or more heating elements, wherein the collection chamber is positioned near the fluid inlet and configured to preheat the fluid received in the fluid inlet before the one or more heating elements heat the fluid.
50. The convection oven of claim 49 , wherein the collection chamber includes a chamber wall that contacts the fluid received in the fluid inlet and radiates heat from the collected heated fluid to heat the fluid received in the fluid inlet.
51. The convection oven of claim 42 , wherein each of the one or more heat transfer ducts includes a bent duct portion disposed between and connecting the first duct portion and the second duct portion, the bent duct portion bending around the distal end of the partition wall.
52. The convection oven of claim 51 , wherein the first and second duct portions of each of the one or more heat transfer ducts have an upright orientation, with the bent duct portion being positioned below the first and second duct portions.
53. The convection oven of claim 42 , wherein the first direction of movement of the process air along the circulation path in the first passage portion is downward and the first direction of movement of the process air along the circulation path in the second passage portion is upward, and wherein the heated fluid in the second duct portion in the first passage portion moves upward and the heated fluid in the first duct portion in the second passage portion moves downward.
54. The convection oven of claim 42 , wherein the first end portion of the first passage portion is positioned adjacent to the second end portion of the second passage portion.
55. The convection oven of claim 42 , wherein each of the one or more heat transfer ducts includes a third duct portion extending from the second duct portion and terminating at a duct outlet from which the heated fluid is removed from the heat transfer duct, the third duct portion being positioned downstream in the first direction of the first duct portion in the circulation path.
56. The convection oven of claim 55 , wherein the third duct portion is transversely arranged across the circulation passage.
57. The convection oven of claim 42 , further comprising:
a fluid circulation element configured to move the heated fluid from the first duct portion to the second duct portion of the one or more heat transfer ducts in the second direction opposite to the first direction.
Priority Applications (1)
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US16/053,552 US20180352818A1 (en) | 2015-02-03 | 2018-08-02 | Convection oven with linear counter-flow heat exchanger |
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US16/053,552 US20180352818A1 (en) | 2015-02-03 | 2018-08-02 | Convection oven with linear counter-flow heat exchanger |
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US16/053,552 Abandoned US20180352818A1 (en) | 2015-02-03 | 2018-08-02 | Convection oven with linear counter-flow heat exchanger |
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CN109883189A (en) * | 2019-02-27 | 2019-06-14 | 昆山市瑞浦鑫涂装机械有限公司 | A kind of oven combustion chamber afterheat utilizing system |
Also Published As
Publication number | Publication date |
---|---|
CN107105676A (en) | 2017-08-29 |
US20160219888A1 (en) | 2016-08-04 |
WO2016126738A1 (en) | 2016-08-11 |
US10314315B2 (en) | 2019-06-11 |
CA2920091A1 (en) | 2016-08-03 |
EP3253217A4 (en) | 2018-09-12 |
EP3253217A1 (en) | 2017-12-13 |
CA2920091C (en) | 2018-04-17 |
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