AU2016204889B2 - Convection oven - Google Patents

Abstract

Provided is an oven for cooking food, the oven comprising a cooking chamber for receiving the food, a blower wheel for moving gas in the oven chamber, a heater for heating the gas, and a water system configured for delivering water to the blower wheel The blower wheel, is rotatable for drawing gas ito the blower wheel axially frwom a suction side of the blower wheel and for outputting gas radially from an output side of the blower wheel The water system is configured for delivering water to a third side of the blower wheel opposite the suction side.

Description

FIELD OF FEE INVENTION

[0001] The present Invention generally relateS: to ovens and more particularly to a forced-air .convection, oven for" baking bread: products, among: other things.

B&CKBRpUND OF THE INVENTION

[00023 Certain types of food products are especially difficult to cook quickly and uniformly. Bread is one such product. Fox proper cooking, the inside of the dough needs to be completely baked while the crust Uniformly browns to the desired color. conventional bread-baking ovens have various drawbacks.

[0003] Bor example,. conventional ovens· do not provide:: convenient access·1 to' electrical, components of: the· ovens for servicing or ether purposes. Typically, a control panel or other part must be disassembled to access electrical parts. Further, once disassembly enables access to the electrical components, the components are hbt mounted within the oven in a position or orientation for convenient servicing. Thus, there exists a need for an oven that provides convenient access to electrical components of the oven having the components mounted in a position and an orientation conducive to servicing of the components, [00Q4J another drawback ox known ovens is that steam formed during the baking process is not disposed of in a desirable or efficient manner. Some ovens simply expel the steam into the atmosphere surrounding the oven (e.g., inside the baking room or restaurant). Other ovens expel the steam through an exhaust that leads to the outside atmosphere. Some ovens provide a self-contained steam condensing system, but a more efficient self-contained system is needed.

[0005] Drawbacks also exist in the steam generation systems used to inject water against heated rotating blower wheels to generate steam for the cooking process in existing ovens. For examp}e,:!iome water ugeefion systems mvoive aiomfeers:haying complex designs ip combination with the blower wheel ta ;aioffiize injected water. Other water imection systems aye simpler, but result in less efficient generation of steam. Further, in some water injection systems, some of the: injected water does not ...turn to .steam and subsequently contacts; the product to be cooked (e,:g,,br.ea.d:fr tuidesirably ai|eetj:n| tpe hooking process. Thus,: g simplified, more efficient water injection system is needed. |0006) fihhtly,: conventiMia! convection ovens incorporate \ artous types of systems }dr circulating hot gas (e g., air) throughout the cooking chamber, including systems having a reversible, variable speed fan. oftemfin! .to achteve:tiniibntV:C0:Ofei.iig of food in the cooking chamber. 10007} There is a need, therefore, for an improved oven which .meets one or more of the above needsc

StlMMAiiV jOOOS} In a first hspeet, the present invention provides anovenfor cookmg food, the oven comprising: Ο cooking chamber for recei ving the food. a blower wheel for moving gas in the oven chamber, the blower wheel^being rotataMe for drawing gas into the blower wheel axially foom a suction side Of the blower wheel and for outputting gas radially from an ou tpu t side of the hfower wheel, a heater lor heating the gas. and a water system configured for delivering water to a third side oFthe hiower wheel opposite the suction side. pmij in a second aspect,, the present invention provides a method ofoperating an oven, the method comprising: fotatfog a hioNVer wheel m a recirculation conduit, o f the oven to move gas from a cooking chamber of the oven into thefreeireulaffott condnif and back to the cooking chamber, the foiating hlower wheel moving: the gas by drawing gas into.the.·blower wheel axially from a suction side of the blower wheel,and outputting: gbs radially from an dniput side of the blower v heel, and delivering water to a third side of the blower wheel Opposite the suction side of the blower wheel |(KHf8*2{ in prefei red enxboitarts of iht; first aspect of foe invention, ihe oven is ehafocterized in that: (a) the blower wheel^c!«des.^:'w^#:rnetnber and aplurality of blades, the water system is configured for delivering the water.to the wheel member, and die wheel member is ccmfignred for dispendng the water radially |ropt?#e:iwh#bTOemb^f»more preferably: th&amp;blower wheel is rotatable: about an axis Of rotation, and the wheel member includes an annular region concentric with the axis of rotation for receiving the water; dr the oven further comprises a shaft .connected;#' the' wheel member for rotating the blower wheels: the blades being supported by the wheel member for rotation, by the 'Shaft;: dr the wheel: member is configured to disperse the water radialfy as water droplets; or the wheel member comprises a circular plate; (hi the/water systertr includes a water tube haying an outlet positioned for delivering water to the third side of the bloweie:wheel:,:mo:re prefemblyflie water tube outlet terminates sliort pf the third side of the blpwer wheel; I e 1 the o ven "further comprises a recirculation epndaft;.^:cireulafmg· gas bom the cook fog chamber back to the cooking chamber, the blower wheel being located in the recirculation conduit, more preferably the cooking chamber has an exhaust for exhausting gas ifora the cooking chamber to the recirculation eonduit, the suction side .-of the blower wheel being adjacent to and facing the exhaust, and the output side of the blower w:heet facing transversely with respect to the exhaust, sffli more preferably: the third side of the blower \yheelifWes/'awuy:f«3m't)je"eX'hau$i;':'Or the water system includes a water tube having an outlet, and the suetiori side of the blower wheel is:located between the tube: outlet and the exhaust; fd) the. water system comprises d water tube having an outlet^tbeffbii^^d.^pf fhefolower wheel Spf delivering winter to theliltird side of die blower Wheel, the oven comprises a recirculation conduit for circulating gas fern fo chamber back to the cooking chamber, the blower wheel being located in the recirculation conduit, the cooking chamber has an exhaust lor exhausting gas from the cooking charnber to the recirculation conduit, the suction side of the blower wheel is petitioned adjacent to and facing the exhaust; and the suciiodside of the htower wheel is located between the water tube outlet and the exhaust, still more preferablythe blower wheel includes a wheel member and a p lurality of blades, the wheel member being located between the outl et of the wa ter tut® and the exhaust, the outlet oi (he water tube being positioned for delivering water to the wheel member, the wheel member being dopi%ureb;fo:F dispersing the: water radially Worn the wheel member while the blowerwheel is rotating, still more preferably ihe oven further comprises a shaft eonhecied to the wjieel member for rotating the blower wheel, the multiple blades being supported by the wheel member for ropidmhy the shady still more preferably the wit eel member includes pfenhulih'regidn eonflgured for receiving the water from the tube outlet as the blower wheel is rotating, the annular region being concentric wi th the shaft, still mere preferably the water is delivered to a wheel member of the blower wheel, and the method ftirthef comprises dispeming the water radially fifoni the Wheel rafember while rotating the blower wheel, stiH more prefembly the Water is dispersed radi ally as droplets o f water ftforn the wheel member; (e) the blower wheel draws gas from ihe cooking chamber into the recimulPoii conduit foora an exhaust iir the cooking chamber, and the suction side of the blower wheel is positioned ad|afcent to and laces the 'exhaust. | <1008,3 j hi preferred embodimentsof the third, aspect of the invention, ihentefftod.ls eharaeierized in that:: (if the. water is delivered?To a wheel member of the blowerWlieehundfe comprises dispersing the water radially from ihe wheel member whilerotating the/blower Wheel, more preferably the water is dispefeed radially as droplets of water ironi the wheel member; of {III the blower wheel draws gas from the cooking chamber into the recirculation conduit from an exhaust in: the cooking chamber,:;and the suction: sidei offlre blower;:wheel is positioned adjaCent to add laces the exhaust, {0008.4 j One aspect of the present invention is directed to a convection oven comprising a cooking chamber for receiving food to be cooked, a blower ter circulating gas |e,gy ;nr) through the cooking chamber, a heater for heatingfhe gas, and a housing for housing eiectricai componentsoi the oven. The housing comprises front, hack and side walls.

The from wall is movable from a first position in which the electrical components are concealed within the housing to a second position in which the electrical components are exposed. The electrical components are mounted within the housing at positions relative to the front wall such that the electrical components may be conveniently accessed by ait operator when the front wall is in the second position. 10009! to another aspect, the oven comprises a cooking chamber for receiving food to be cooked, a blower for circulating gas (e.g„ air) through the cooking chamber, and a heater for heating the gas, The oven also includes a vapor collection system for collecting vapor from the cooking chamber during a cooking event. The vapor collection system comprises a condensing device above the cooking chamber having an inlet communicating with the chamber for receiving vapor and an outlet for draining condensed vapor* The condensing device comprises a coil comprising a plurality of burns configured for gravity feeding condensate to the outlet, tooioj In another aspect, the oven comprises a cooking chamber for receiving food to foe cooked, a variable-speed, reversible blower for circulating gas (e.g., air) through the cooking chamber, the blower being operable at more than two speeds when activated, and a heater for heating the gas. The oven also includes a control system comprising an operator input and a controller responsive to the operator input for controlling the rotational speed of the blower during the cooking event according to a predetermined speed curve which includes at least two reversal events. Each reversdl event comprises a deceleration of the blower as it rotates in one direction from a first rotational speed on said speed curve to a zero rotational speed, followed by an acceleration of the blower as it rotates in an opposite· direction from zero speed to a second rotational speed on said speed curve, the second speed being either the same as or different from said first speed. In one embodiment# the shape of the speed;curve is substantially non-lineai '.between tho: end:· of one reversal event and the beginning of another reversal event. tooii] In another aspect, the oven comprises a cooking chamber for receiving food to be cooked, a variable-speed, reversible :blower for· circulating" gas.:' (e. g,, air) through;: the.: cooking chamber, the blower being operable at more than two speeds when ^activated,:: and a. heater· :,fhr heating the'gas- .The, oven includes·· a .control: System, comprising an operator, input and •a;:: controller 'responsive to the operator input for' 'controlling1 the rotational speed of. the blower during the cooking event according to a'.predetermined, speed curve. In one embodiment, the:'speed cniy®.''fo.a:s.. no substantial linear components,. £00123 The Invention is· also directed to a· method, of cooking: food in a convection oven comprising· a cooking Chamber for ..receiving·: food .fed. fee. cooked,: fhe .method. comprising. the '•steps 'of· placing^ .food: in the cooking chamber, and operating a blower of the oven to circulate heated gas (e.g., air) through the cooking chamber to cook the feed during a cooking event.

The operating step comprises controlling the rotational speed of the blower during the 'OCoking: event .according to a predetermined Speed curve which includes at least two reversal events, Bach reversal eveht comprises a deceleration of the blower as it rotates in one direction from a first rotational speed on the speed curve to a zero rotationai speed, followed by an acceleration of the blower as it rotates in an opposite direction from zero speed to a second rotationai speed on the speed curve, the second speed being either the same as or different from said first speed. In one embodiment, the shape of the speed curve is substantially non-linear between the end of one reversal event and the beginning of another reversal event, [0013] Other objects and features will be in part apparent and in part pointed out hereinafter,

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Fig. 1 is a perspective view of one embodiment of an oven of this invention; [0015] Fig, 2 is a front elevation of the upper section of the oven of Fig. 1, shown partially in section; [0016] Fig- 3 is an enlarged portion of Fig, 2 showing blower details; [0017] Fig, 4 is a perspective a side wall of the cooking "chamber· of the upper· section of the oven;:? [0018] Fig. 5 is an elevation of the side wall of Fig. 4; [0019] Figs. 6 and 7 show alternative hole patterns; in the. side wail of Figs. 4 and 5; [0020] Fig. 8 is a perspective a blower wheel of the blower used in the upper section of the oven; [0021] ' Fig. 9 Is· a plan, view of; the· blower wheel? [0022] Fig. 10 is an exploded view of the blower wheel? [00233 Fig. 11 is a view Illustratinga water:; injection system of "the upper Sectibb of the .oyenf [00243 Fig, 12 is a perspective view of the upper Section of the oven with parts of a hood removed to: show details of a vapor collection system; [0023| Fig. 13 is a perspective of a lower section pf the oven; [00263 Fig * 14 is a front elevation of the lower section of the oven of Fig. 12, shown partially in section; [00273 Fig, IS is an enlarged portion of Fig. 14 showing details of ft blower and wafer injection system in the lower section of the oven; [00283 Fig. 1β is a perspective similar to Fig. 13 but with the door open and the bottom wall of the cooking chamber removed to show details; [00203 Fig. ISA is an enlarged portion of Fig. 16 showing details of: the water injection system in the lower section of the oven; [003Q3 Fig. 17 is an enlarged portion of Fig. 16 showing details of the; blower and water injection system; [00313 Fig* 10 a perspective of a side wall of the cooking Chamber' of the lower section of the oven; [00323 Fig* 19 is an elevation of the side wall of Fig* 18; [O0333 Fig. 20 is a perspective similar to Fig* 1 but showing g second, embodiment of a vapor: egldecfcion system on the oven; [0034J Fig. 21 is a perspective of an Upper section of the oven of Fig. 20 with parts of the vapor collection system removed to show details and with arrows generally indicating flow of steam and condensate through the vapor collection system; [00353 Fig. 21ft is a plan view of the upper section of the oven of Fig. 20 with parts of the vapor collection system removed to show details and with arrows generally indicating cooling air flow over the vapor collection system; [0Q36J Fig. 22 is a vertical section on line 22-22 of Fig. 21:/ [0037] Fig. 23 is a perspective of a portion of finned tubing; £00301 Fig. 24 is a wiring diagram; £00391 Figs. 2:5&amp;~25E are: graphs showing various blower speed and direction protocols with differing numbers of blower reversal events; [0040] Figs.26A~20C are graphs showing various blower speed and direction protocols with differing frequencies of speed change; £00434 Fig. 27 is a graph showing a blower speed profile for a certain food product; £00421 Fig. 28 is a perspective of a housing for housing electrical components of the oven; £0043] Figs. 29&amp;~29β are sequential perspectives of the housing of Fig. 28 showing a wail of the housing moved from a closed position to an open position; £0044] Fig. 30 is a view similar; to Fig. 3 Showing an enlarged portion of another embodiment of a blower and water injection system; £0045] Fig. 31 is a perspective view a blower wheel of the blower shown in Fig. 30;: £0046] Fig. 32 is a view illustrating the steam gene ration/water in lection:·: system· of''pig. 3:0; [0047] Fig. 33 is a perspective of another embodiment of the lower section of the oven: with the door ©pen and the bottom wall., of. "the cooking chamber removed' to·; Show details; and [0048] Fig. :34 fs ap enlarged portion of Fig. 33 showing:: details of the blower and water injection, system. £0049] Gbrresponding reference' characters indicate corresponding parts throughout the drawings..

DESCRIPTION OF THE FREFERRED EMBODIMENTS £00501 Referring to the drawings, Fig. 1 illustrates: one embodiment of an oven of this invention, indicated generalIp by the reference «umber 1. The oven is adapted for cooking and baking products such as bread, among other things,: and includes a cabinet, generally designated 5, having an upper section 5A and a lower section SB. If the oven 1 is used in a bread making: process, the dough is first proofed in the lower section 58 of the oven and then; baked in the upper section 5A., (As will be understood by those skilled in the bread-making field, ’^proofing” is a continuation of the process ,of yeast fermehtatioh which increases the volume or "rise" of the shaped dough, and an oven used to 'hr jo ft bread is Often referred to as a "proofer” or "proofer oven.*'} POSiJ .deferring to Figs. 1-3, the upper section 5Ά of the oven 5 comprises S cooking < o. g., baking) chamber 11 defined by a: top wall 13, a bottom wall 15, opposite side walls 17, and a back wall 21. The chamber 11 Is accessible by opening a door 25 which closes the front of the chamber. One or more rack supports 29 are secured to the walls of theChamber for supporting a number of food racks 33 in the chamber, three such racks being shown in Fig. 2. Each rack is sized to hold a number of pans of bread dough. It will be understood that the number and size of the racks 33 can vary without departing from the scope of this invention. The cooking chamber 1.1. is surrounded: by an upper housing, generally designated 41 in Fig. 2, haying a top «all 43, a bottom wall 45, opposite side wa!is 47 and a back wall 51. The top and Side walls of the housing 41 are spaced from respective walls; of the cooking chamber IT to provide a cohduit system or flow path 53 for circulating heated nir {Or other gas) to, through and from the cookang chamber II. As: :shown:: in Fig:. 2:, the conduit system 53 comprises an upper portion; |3:@ .above ::fhe; cooking Chamber 11 and side portions 33b at opposite sides of the cooking chamber 11. Other flow path configurations may be used.

[00523 A blower, generally indicated at 61 in Fig. 2, is mounted in the upper portion 53a of the conduit system 53, adgacent the top" of the; upper section 5A of the even,.: for circulating air (o;r other gas) through the': conduit system^ in 'the' illustrated ''epbodibent,'' air eaters the cooking chamber' 1.1,. through a plurality of entry 'openings 65 in. the side wails 17 of! the chamber (Figs . 4' and! :5.) and exits the chamber through an exhaust opening 69 in the top wall 13 of the chamber. A heater 71 is provided for heating the air being circulated. By way of pxsmpie., the heater may comprise one! of more electric resistance heating elements in the upper portion 53a of the conduit system 53 ideated adjacent the top wail 13 of the cooking chamber 11. The heater 71 heats the air as it leaves the chamber before it is re-circulated back to che chamber via the conduit system.

One or more temperature sensors 75 (Fig. 23) are provided in the cooking chamber 11 for sensing the temperature in the chamber and providing feedback to the control system of the oven. In one embodiment, two temperature sensors '75A, 75B axe provided for sensing temperature in different fanes of the cooking chamber 11. The cooking chamber is illuminated by lights 79 mounted on the bach .«dll of the 'Chamber 11.

[0053] Referring to Pigs. 4 and 5, the entry openings 65 in the side walls 17 of the cooking chamber 11 are sized and configured for directing heated air to the food on each rack in the chamber. In general, the number and/or size of the openings 65 (i.e., the overall air flow area) associated with each rack level increases from the top of the cooking chamber: toward the bottom of the chamber to insure that substantial1v the same volume of air is provided to each level of food on the chamber. (Without such an increase in flow area, more heated air would enter the chamber at the upper levels than the lower levels,)

The entry openings 65 are also configured in shape, size and location to achieve the desired baking characteristies. {¢$541 In the particular configuration of Fig. 5, the openings 65 comprise three distinct patterns, namely, an upper pattern 65A for delivering heated air to iood on the upper rack 33; an intermediate pattern 65B for delivering heated air to food on the middle or intermediate rack. 33; and a lower pattern 65C for delivering heated air to food on the lower rack 33. As shown, the: upper pattern 65&amp; comprises a first plurality of relatively large holes (e.g., 0.312 in,-diarneter circular holes) aligned in a horizontal row above the upper rack lor directing heated air toward upper portions of the food on the hack, and a first plurality of smaller holes; {e.g., 0.125 in. -diameter circular holes) below the larger holes arranged for directing heat toward middle and lower portions of. the food on; the upper rack. The intermediate pattern <5SB .comprises' a second ^Ihraiity of relatively large holes (e.g., 0.312 .dhvtdiamet.er: :cihcular holes) aligned in a horironcai row above the intermediate rack fox directing 'heated'' sir. toward: 'Upperportions of" the:; food on the rack, and a second plurality; pf '.smaller dholes (e.g., 0.125 in,-diameter circular holes) below the larger holes arranged for directing heat toward middle and lower portions of the food on the ihtermediate rack, The lower pattern 65C comprises a third plurality of relatively large holes {e.g,, Q>312 in,-diameter circular holes) aligned in a horizontal row above the upper rack for directing heated air toward upper portions of the; food on the rack, and a; third..plurality of smaller holes {e.g., 0.125 in,-diameter circular holes) below the larger holes arranged for directing heat toward middie and lower portions of the food on the lower rack. It will be observed that the number and location of holes vary from pattern to pattern. In general, the arrangement is such that the overall or total flow area of the Openings of the first pattern 65A of holes is less than the overall or total flow area; of the holes in the second pattern 65B, and the overall or total flow: area of holes of the. .second pattern is; -less "than the; overall Of total flow area; of. the holes; in the third pattern 65C to provide a: more; uniform distribution of air to the different leveis. The specific configuration '(sire, .shape and locations') of the holes in the; 'various, patterns; will vary according; to: "the side and shape of the. food.; product in the cooking chamber and accordihg to the desired qualities of the food, after.:It has. finished baking,. By way of example but hot limitation, the openings day be circular holes varying in diameter from 0.060 in. fs 1,(38 in., or they may be; slots having rounded ends with a size that can range from 0.0¾¾ in. wide by 0:..50 in. long to: 0.,:38: :.in.:, wide fey l.S in... long..; fOOSSJ Figs. 6 and 7 illustrate different entry opening configurations. In Fig. 6, the entry openings 85 of each pattern 85&amp;, 8SB and 85C are all of the same size and are arranged in a generally rectangular matrix of regularly spaced openings extending alongside the food on the racks. By way of example put not limitation;, the openings may be circular holes varying In diameter from 0.060 in. to 1.00 in., or: they bay be slots' .having: 'rounded .ends: with· a· size that can range from 0.060 in. wide by 0.50 in. long to J3.38 In. wide by 1.5 in. long:. In Fig. 7* the entry opening patterns:1 95 A, 953 and 95c each include; a: single tonly· one) large opening 95 extending alongside the food on a respective rack 33. It will be observed that the sizes of these openings 95 do not vary.

[00561 In one embodiment {Fig,, 3).., the blower 61 for Circulating air through the cooking chamber 11 comprises a variable speed, reversible blower motor 101 mounted in a housing 105 mounted on a top wall 1G7 of the oven. The blower motor 101 has an output shaft ill which rotates in a bearing lit about a generally vertical axis 117. The output shaft of the motor 101 is coupled, to ah input shaft 119 of a blower wheel, generally designated 121, located In the upper portion 53a of the air-conduit system 53 adjacent (e.g., immediately above) the exhaust opening 69 in the top wail 13 of the cooking chamber 11. The blower motor 101 is operable to rotate; the blower wheel 121 about the axis of rotation ll:7;i to circulate air through the conduit system 53 and cooking charter: 11 at velocities: and flow rates: suitable for, cooking'. Exemplary: velocities Include 0-600 ft/min, 1 €-300 f't/mln, and 30-220 ft/mih. .E-otation Of the blower·' wheel: 121 creates suction at the suction side 1.21a. of the blower wheel: ti,,,e:,,. the·· lower: ;portion of'the blower· wheel adjacent the •exhaust Opening 69) to pu .1.1 gas: from the conking chamber'll, through.'the: exhaust·; opening 63:, gas is. expelled: from" the blower wheel 121 at the output {exhaust) side 121b of the blower wheel {i . e., the left and right sides of the blower wheel as shown in Fig. 3) to circulate: axe through the conduit system 53 to the cooking chamber 11.

[00573 In one embodiment, the blower motor 101 is a 230 VAC, 3-phase, 1.2 amp, 60 Hz, 1/3 hp induction motor having a speed which is infinitely variable over a range of speeds, e.g., 50-3450 RPM. One such motor is model number P55LVPDB-1405 available from Emerson Electric Company. In another embodiment, the motor may have a speed which is variable in small increments (e.g., three, four, five, six, seven, eighty nine or ten increments, or more than ten increments, or more than twenty increments, or more than thirty increments) over a range of speeds. Other variable speed, reversible motors operable in the same or other speed ranges, voltages or power may also be suitable.

[0058] Referring to Figs. 8-10, the blower wheel 121 is a flat bladfed wheel comprising an upper member 131 which, in the illustrated.! embodiment, comprises a circular plate (also designated 131), a series of parallel fiat blades 135 mounted on the circular plate, and a hub 139 on the circular plate for receiving the input shaft 119 of the blower wheel. The blades 135 are spaced at equal intervals arbuud the circular plate 131 adjacent the periphery of the -plate'and are orientedin a radial direction with respect to the axis of rotation 117 of the wheel 121 so that they lie in generally vertical radial planes relative to the axis of rotation* The blades 135 are secured in position by flanges 145 affixed (e.g., spot welded or riveted) to the circular plate 131 and by a lower member 147 which, in the illustrated embodiment, comprises in alignment ring (also designated.14:7), affixed (e.g., Spot welded) to the blades. An even or odd number of blades 135 may be used, other blower-wheel" designs1 may' be used.

[0059] Referring still to the embodiment illustrated in Figs. 8—iO, at least one of the (blades 135 o £ if he" blower .wheel 121, and desirably several of the blades, comprises a water-dispersion formation (151 for dispersing. Water" into, the cooking chamber 11 in a manner to foe described later. In this embodiment,- each such formation 151 comprises art integral Extension hi the blade 135 projecting in a radial direction outward from the blade generally in the same radial plane as the blade. The extensions 151 may have other shapes without departing from the scope of this invention^ [0060) Referring to Figs, 3 and: 11, a water injection systeifW' 'generally indicated lit*· l:s provided:: :for delivering water to the blower 61, and specifically the; blower wheel 121, for dispersion into the air conduit system 53 and cooking chamber 11. The injection system: 171 comprises at least one: injector 173 mounted adjacent the blowei wheel 121, and a line 177 for supplying water to the injector. A needle valve 181, solenoid valve 183 and pressure regrtlator 18:3 are provided 'Upstream" of" the injector· for controlling flow to the injector:.;

In one embodiment, the watef irtjedfcor 173 comprises a 0.25 in. diameter stainless Steel tube With a squafe-cut end. The components of the injection system 171 may be mounted on a top wall 107 of the even: at a location where the injector 173 extends down from the top wall to a position for delivering water for impact against the 'Water dispersion formationfs) 151 on the rotating blades 135 of the heated blower wheels By way of example, the lower end of the injector may be spaced about 0.5 in. above the dispersion; formation (s) 151,: As a· result, Water is dispersed .as a dine·: spray or steam mist into the air conduit system 53 and heated:: by the he.at.ing elements 71.. to form a vapor; {steam) :.which., is carried into the cooking chamber 11. Where it settles at a layer an the bread (dr dthex product) ho promote the formation of. a thin crust which is uniformly browned. The number of injectors 173 can vary, £00613 The; injector system 171 is operated to perform a desired number of water injection eventa (e,g,i 0-4) during a cooking event. Each Such event may include, for example, a number of time-based cycles each comprising a repeat of one second on and two seconds off, Other injector configurations and injection cycles and frequehbi.es are possible.

[00621 'The cooking chamber 11 and air conduit system 53 is generally a closed system in which substantially the same air re-circuiates oyer and over daring a cooking event. As cooler air is: heated, as during initial start-up of the oven, the volume of the air in the conduit system: and cocking chamber will increaseTo .prevent excessive build-up of air pressure· inside' the cobbing chamber, a relief valve 201 is provided to release air from the conduit system 53 to the atmosphere. Ah exemplary relief valve 201 is shown in fig. 12. It comprises a short tubular fitting having an inlet end communicating with the air conduit system 53 and an Outlet end which is closed except for a small opening 205 sized to provide suitable pressure relief. By way of example, the opening may be a 0.375-in. diameter opening.

[00633 Referring to Figs, 13-19, the lower (e.g., proofing) section 5B of the oven 1 comprises a second cooking (e.g., proofing) chamber 225 defined by a top wall 227, a removable bottom wall 229, opposite side walls 233, and a back wall 235. The chamber 225 is accessible by opening a door 241 which closes the front of the chamber. One or more rack supports:: 243 are Secured to the wails of the chamber for supporting food racks 251 in the chamber. In this particular embodiment,, up to nine racks can be used in the cooking chamber 225, and each rack is sized to hold a number of pans of bread dough. It will he understood that the number and capacity of the racks 251 can vary without departing from the scope of this invention. The cooking chamber 225 is surrounded by a housing 261 having a bottom wall 263 and opposite side sails 265 spaced frost respective walls of the booking chamber 225 to provide a conduit system or (flow path 2?1 for eirchiating heated air (of other gas) through the 'cooking chamber.,, Other flow path.

Cohfigurafions may be used.

[0064J A blower, generally designated 281 in Figs. 14-17, is mounted below the bottom wall 229 of the cooking chamber 225 for' circuiating' air "(or other gasi through the air conduit, system 2?1, and cooking, chamber' .225, In one· embodiment, the blower 281 comprises a single speed, single direction 'blower motor 285 driving a blower wheel 287 positioned in the air conduit system 271 below the bottom: wall 229 of the cooking chamber. The blower wheel 287 rotates about a generally vertical, axis 291., In the: illustrated embodiment:, .ait: enters:: the cooking chamber 225 .through a. 'plurality of entry Openings.: 3:01 in the side walls 233 of the chamber and exits through an exhaust 305 (Fig, 13) in the bottom wall 229 of the chamber, A heater 311 comprising, for example, one or more electric resistance, heating, elements' heats- the 'Circulating:: air, The heating elements 311 are located in the air conduit system 271 below .the·1 bottom, wall 229 of the cooking chamber 225, Other locations are possible, A temperature sensor 321 (Fig, 24) is provided in the cooking: chamber 225 for sensing the temperature in the chamber and providing feedback to the control system of the oven. The cooking chamber 225 is illuminated' by 'lights325 mounted in the chamber,, erg,, on the back wail 235 of the chamber. 100651 Figs, 18 and 19 show an exemplary pattern of entry openings 301 in the side walls 233 of the cooking Chamber 225. (Only one side wall 233 is shown, the opposite side wall being essentially identical. However, the opposite wallJ233 may have different entry Openings 301 to balance air flow to food products within the cooking chamber 225.) The entry openings 301 are arranged and configured for directing heated air to the food on the various racks 251. In general, the number and/or size Of the openings 301 (i.e., the overall air flow area of the opening or openings) associated with each: rack level increase's from the bottom of the: .cooking chamber· 22:3 toward the top of the chamber to- Insure that, substantially the '.same: 'volume· or air. is provided to each level of food in the: Cooking: chamber 225, in a similar (but inverted) manner as described previously in regard to the entry openings; 65 in the upper cooking: chamber 11, 10066] In, the particular configuration of Figs, 18 and IS, the ehtry openings 301 are elongate rectangular openings, one such opening extending horizontally at each rack level. As will be: observed, the height of the openings 301 gradually increases from the bottom toward the top of the side wall 233, with the uppermost openings 301 having approximately the same height,; Other entry opening configurations are possible. In any event, heated air is delivered through these openings 301 and into the cooking chamber 225 at: velocities and flow rates which are suitable for the cooking process being carried out, e,g«, a bread proofing process,.: [00673 A second wateh injectioh system, generally indicated 351, is provided for delivering water to the output [exhaust) side; 121b of the blower wheel 287 for dispersion: into "the air conduit system 271 where it is atomised, h.eated> vaporized and delivered with the heated air to the booking chamber 225 to promote the cooking (e.g., proofing) process. (See Figs. 15-17). The water injection system 351 comprises at least one injector.::355 mounted below the bottom wail 229 of the cooking Chamber. generally adjacent the blower wheel 287, although other locations are suitable. Water is supplied to the injector 355 via a supply line:389. &amp; valve 391 in the supply line 389 is operable for controlling flow to the injector 355 (see Fig. 16J&amp;) , In one embodiment, the water injection system 351 is operated according to a program which can foe varied depending on the particular cooking process being performed in the oven. By way -of example1,, the injector system 351 may be operated.· to perform: a number of water1 injection1 events (e,g ., Q~4) during a cooking event, with each: such injection event· including a number of time-based cycles each comprising a repeat of one second on and two seconds off. In another, embodiment, the water injection system 351 is Operated according to a humidity control system 393 (Fig, 24) comprising a closed loop feedback control having a humidity sensor 395 mounted within the conduit system 271 and controller 397. Humidity detected: by: the humidity sensor 395: is reported to the controller 393. If the humidity is above a specified high limit, the controller 397 signals the water injection system 351 to deliver less ox no water to the conduit system 271 to decrease the humidity.·: If the humidity is below a specified, low limit, the controller 393 signals the water

Injection; system 351 to deliver more water to the conduit system 271 to increase the-humidity,· Other- injector configurations and injection cycles and frequencies are possible, 10068] A vapor collection system, generally indicated at 401, is provided above the; upper section 5A of the oven {see Figs, 1 and 12). The system 401 comprises a hood generally indicated at 405, having a front portion 407 which overhangs the doors 25, 241 of the upper and lower sections SA, SB of the oven, and a rear portion 411 comprising sideswalls 413 extending above opposite sides of the upper section 5A of the oven. The front and rear portions 407, 411 are separated by a partition 421 having two exhaust openings 425 therein. An exhaust fan 431 is mounted on top of the upper section of the SA of the oven behind one Of the two exhaust openings 425. {The position of the exhaust fan 431 may vary depending on the particular^· installation. In general, it is desirable to: mount the fan adjacent the side of the door 25 opposite the: hinge to maximize the amount of vapor collected^) Vapor released from the cobbing chambers' 11, 225 when the doors are opened.' ίϋ captured by'the front: portion 4:07' o;i the· hood, and exhausted through one or both of the openings 425 and directed to a vent 431. In the' illustrated embodiment'^ only one exhaust· fan 431 is used, and vapor is, exhausted through the opening; 425 behind Which the. fan; is mounted. The vent is adapted for connection to a: flue 435 ;{Fig. 1} communicating with atmosphere, either inside or outside the building in which; the: oven· 1 is installed. fdd69j Figs. 20-23: .illustrate an· alternative':: vapor col lection system, generally·· designated 451, which eliminates: the -need· for a vent and/or flue as in. the previous·:, embodiment..

In this system: 451, vapor {steam:) from, ftp cooking chamber 11 is vented up, through ;a tubular member or other vapor· conduit 455 communicating with the chamber 11 to the. inlet. 4:53 of a steam condensing device 461 mounted on the top wall K}7 of the oven inside an enclosure 465. {e.g.y, ::hoq.d) . Steam In the cooking ..chamber 11 Is: vented up through thevconduit .455 as a result of -the. difference between the ptessurs inside the cocking chamber-11 and ambient pressure. No assistance (e.g., a fan or egmprsssed air source) is required to move steam through the vapor collection system 451. In one embodiment, the steam condensing device 461 is a condensing coll (also designated 461) comprising a plurality: of helical turns 467 which wind down away from the inlet. 45:7 for gravity feed, of condensate, to .an outlet 475: of the condensing device. In the illustrated embodiment, the coil 461 surrounds or wraps around the housing 105 which houses the blower motor 101. The slope at which the helical turns 467 wind down may be any slope sufficient to cause gravity feed of condensate to the outlet 475, such as a slope between 1 and 20 degrees. In one embodiment, the slope is a 5 degree slope sufficient to cause gravity feed of condensate while also accommodating a 3 to 4 degree oufcof-level floor condition. The flow of steam and condensate- through the coil 461 is: generally indicated by arrows in Fig, 21. The outlet 475 ..communicates: with a suitable drain of other collection device 479 for disposal of the condensed liquid.

[007Q3 in ..one embodiment, the condensing coil 461 desirably comprises finned tubing. Such tubing may comprise a-tube 481 having fins 483 coiled around and extending radially from the tube, as shown in Fig. 23. One condensing coil 461 suitable for this purpose is a coil formed from 1.0 in, OD finned stainless steel tubing sold under the trademark Finbraze® by BNF International Inc. of Mobile Alabama, Suitable finned tubing can be constructed by different methods. For example, fins 483 can be brazed to the tubing 481. Alternatively, the fins 483 can be extruded to the tubing 481 by a cold:rotary extrusion process in which continuous helical fins are radially extruded from aluminum tubing. By way of example but not limitation, the condensing coil 461 may comprise stainless Steel smooth-bore tubing 481 with copper fins 483. Desirably, such tubing 481 is constructed by extruding copper helical fins 483 directly onto the stainless steel tubing. Alternatively,:: the fins can be extruded as a •’sleeve’* and heat-expanded to bond to the Stainloss; steel tubing. Several factors must be balanced to accomplish efficient steam condensation, including the inside diameter of the tnbing 401 of the condensing coil 401, the length of the tubing, the surface area {including fins 483) of the ttibihg^ and the slope of the tubing. £0071J Referring to Figs. 21 and 21 A, one or more fans 485 are mounted on the enclosure 465 for moving relatively cool air into the enclosure through one or more inlets 487 in the rear wall of the enclosure, along a path in which the cooling air flows over the ©ogling coil 461 and put; of the enclosure via an exhaust 491. One or more baffles 489 are disposed withih the enclosure 465 to direct the air flow (generally indicated by arrows in Fig. 2ΙΆ) to contact substantially the entire surface area of the cooling coil 461 (e.g., at least 80 percent of the coil) and to prevent "short circuiting" of the air flow from the inlet 487 to the exhaust 491. As a result, steam in the coil 461 is cooled and condensed into a liquid which drains through the outlet 475 of the coil to the collection device 479 for disposal. Louvers 495 are provided in the top wall 107 of the oven for venting hot air which collects: between the housing 41 and: the top· wall 107 bft "the oven into 'the ..enclosure.' 465' where it is also exhausted through .exhaust Alternatively, a natural convection cooled coil, may be used in which the coi 1 is:: large enough such that sufficient condensation occurs: within the coil as a result of natural convection cooling, without: the fan. 4 85. £0072] Referring to the wiring diagram of Fig. 24, the operation of the oven 1 is controlled by a control system 501 comprising, in one embodiment, an operator input 505, a main controller 507 and la ibloverspeed/directlon controller 509, In addition tb· the. components described above, the. drag rata also Includes the following: components"* .transformers 521 for' reducing the voitage/current to the oven lights 79, 325, main breaker switches 525, a high-iimit thermostat 527 for setting an upper temperature limit in the cooking chamber 11, a contactor device: 531 associated with the: heater' 7.1 for the cooking chamber 11, and an oven, door switch.. 535 which" prevents· the operation of the blower unless; the door· :2:5b:of the cooking chamber 11 is closed.

The electrical components of the·. control system 501 are cooled by cooling: fans· 541. htternatively, only.gne cooling fan 531. may be used - 10:0731 The. operator input 505 comprises suitabib/input devices (e.g., a touch screen, switches;,: buttons, or other devices) mbhnted on a control panel 551 at a convenient location on the oven, such as at the front of the oven between the upper and lower sections ;§&amp;, SB of the oven (see Mg, 1). The operator input 505 allows an operator to input for either of the cobbing chambers 11, 225 various cooking parameters, instructions and/or other information necessary or desirable for performing a cooking operation, including the type of food to be cooked, information relating to the speed and direction of blower operation, number of reversals, desired temperatures, desired 'humidity, and desired: cooking times. 10074) The main controller 507 controls the operation of the heating elements 71,..:311, the valves 181, 295 of the water injection: systems :171, 351, the cooling fans; 541, the temperature sensors 75, 321 in the upper and lower cooking chambers 11, 225, the blower 281 in the lower chamber 225, and the humidity control system 393. The main Controller 507 also works in cooperation with the blower controller 509 to control the speed and direction of the blower 81 circulating air through the upper chamber 11.

[0075J In particular, the main controller is programmable via the operator input 505 to operate the blower 61 according to a selected protocol to: .effect a' debited cooking· operation;.: in; the upper chamber 11* This protocol can he; varied depending on the type of food being cooked, the quantity of food being cooked, the desired characteristics to be imparted to such food during cooking (e.g., crispness^ extent of browning), and other factors. The main controller is responsive to operator input to Communicate the appropriate blower speed and direction; informatiOh to the blower controller 503 via .communication .lines designated: .561 i;n. Fig. 24. The bipW'er controlie.r 509 functions to; drive the blower 'motor 101 at the desired speeds and in the d.e'sl're<i direction or directions to operate the blower wheel 121 in a manner which provides the desired; air flow to the upper cooking chamber 11, One controller 505 found to be suitable for this purpose is; a programmable controller model J7 drive supplied by iaskawa Electric America, Inc, [00761 Examples of different blower protocols are illustrated in Pigs, 25-27. Ip general, each blower protocol involves changing the speed of the blower wheel 61 during a cooking event according to a non-linear speed curve, and optionally effecting one: ex more reversal events during the cooking event during which the rotational direction of the blower 61 is reversed, it has been found that operating the blower 61 at different speeds and; periodically reversing its direction causes a corresponding change in the speed and direction of air circulating through the cooking chamber 11, and that a; more uniform baking and browning of the food (e ,g,, bread) is achieved as a result, [00771 Fig, 25A is a graph showing a blower protocol in which the blower motor 101 is operated to rotate the· blower wheel 121 during a cooking event of predetermined length {e.g., 14 minutes) and at rotational speeds which increase and decrease according to the illustrated speed curve 801. In this example, the curve resembles a sine wave, and the speed varies from a minimum Of rpm of 5:0 to a maximum: rpm Of 3450 13 circulate air: through the upper cooking chamber 11 at vMtv'ities ranging from: a minimum Velocity of less than about 30 ft/min to a maximum velocity of no greater than about 600 ft/min, and more desirably to a maximum velocity in the range of 220-300 ft/min. Lower or higher speeds and velocities may alternatively be used. The rotational speed change repeats: four times during: the: cooking event,: ί,Ο,, the freguency is four Changes per cooking (e.g,, baking) event. Further, there are four direction reversal events occurring at intervals during the cooking event;, as represented by the vertical, lines: 605 on the graph, [00783 Each reversal event Is started by a signal from the: main controller 507 to the blower controller 509 to de-energize the blower motor 101 or otherwise cause it to decelerate as it: rotates in one-direction from :a. first1 Rotational speed on the: speed curve 601 to a zero rotational speed, followed by an acceleration of the blower motor as it rotates in an opposite direction from sero speed to a second rotational speed on the speed: curve. fhe second speed may be substantially the same as the first speed or substantially different from the first speed, depending on the shape of the speed curve and the duration of the reversal event. In the latter regard, the duration of each reversal event will depend on the time it takes the blower wheel 121 to decelerate fc zero and then:to accelerate: back up to speed in the opposite direction. The duration in one example is no greater than 30 seconds. The duration is more desirably no greater than 20 seconds, even more desirably no greater than 15 seconds, and still more desirably less than 10 seconds. The reversal events shown, in Fig; 2SA occur at regular intervals, but they can also occur at irregular intervals, depending on the desired cooking "recipe*" to be followed,.

[pp79] In Fig, 25A, the shape of the speed curve 601 Is non-linear between the end of one reversal event, and the beginning of another reversal event. Further, the speed of the blower wheel 121 changes constantly or substantially constantly during the entire cooking event. That is, the speed curve is substantially non-linear or, in other words, has no substantial linear opponents. {As used herein, "substanta 11 y non-linear" and "no substantial linear components" means that the curve has no linear Gomponents lasting more than 45 seconds, or even more desirably no more than 30 seconds:, or even more desirably" no; more than 20 seconds, or even more desifably no more than 10 seconds.) In other embodiments., the Speed Curve may have substantial linear components. |0Q:80j Figs. 25B:-25E show four additional blower protocols similar tg Fig. 25A except that they include three, two, one; and no reversal events, respectively. Figs, 26A-26C show three additional blower protocols similar to Fig. 24; except that the speed change frequencies are five, six and oney respectively.

The number of reversal events and the frequency of speed change can be varied as needed to achieve the desired baking results.

[0081] Fig, 27 shows a different blower protocol in which the blower 61 is operated to follow a Speed curve 701 in which the blower rotates aba substantially constant and relatively low speed (e.g., 690 rpm) for a predetermined period (e.g., 80% of the bake event) and then ramps up to a higher speed (e.g,, 3450 rpm) for the remainder of the baking event. This type of protocol has been found to be useful for certain food products such as cookies where frosen dough is placed in the baking oven and cooked. During the process, the dough is heated slowly at the lower air speeds so that the dough deforms slowly to the proper cookie shape. Once the dough has assumed the proper Shape, the blower Speed is increased to bake the dough more rapidly to provide the desired browning, [0082] Other blower protocols may be used. By way of example but not, limitation,, the protocols shown in: Figs, 25 and 26 above may be modified such fhafc the speed:of the blower remains constant for one or more dwell (holding) intervals along the speed curve.

[OOSJJ As will be described, the desired protocol can be programmed into the oven by the operator using the operator input ibDd, ϊη: particular, the operator input 505 is configured: to enable an operator to select any combination of one or more of the following: cooking time, cooking temperature, number of water injection/steam generation events, maximum and minimum blower speed, frequency of speed Change, and number of blower-reversal events. In addition, or alternatively, the operator input 505 may be configured to enable an operator to select, a type of food to be cooked, in response to Which the main controller 505 automatically selects (i.e., is programmed to select without further opera tor Input:} a predetermined speed curve and number of reversal events for the cooking event.

[0084] The control system 501 desirably includes a USB host adapter 821 that enables connection of a USB memory storage device or flash drive (not shown) for various purposes. For example, end users may import recipes they have created or retrieved from a website or computer. Further, the USB host adapter 821 allows for training and maintenance information stored on a flash drive to he displayed, e.g., on the operator input 505, preferably in the form of a liquid crystal display touch screen (also numbered 50-5} mounted on the control panel 551, Such information may include instructions for baking bread or procedures lor cleaning the oven 1. Information displayed on the screen 505 may include text, photographs/figures, and video.

Maintenance personnel may also use the USB host adapter 821 to import various operating or firmware updates. (0085] Figs. 28 and 29 show electrical components of the oven as described above housed in a housing 831 located between the Upper and lower sections 5¾, 5B of the oven (see Fig. 1}. Electrical components as referred to herein include any electrical, electronic, or associated components. The housing 831 comprises a front wall forming, in the illustrated embodiment:, a control panel 551, a back wail 841, and opposing side walls 843. A chassis 845 extends between the side walls 843 at a location forward of the back wail 841. The chassis 845 is desirably secured by rivets or screws td respective side-walls 843, to the bottom wall of upper oven section 5A, and to the upper wall of lower oven section SB. The control panel 551 is mounted on two slide rails 84? having slide connections with the side walls 843 of the housing 831. In the illustrated embodiment, each slide connection between a rail 847 and respective side wall 843 comprises two screws 849 extending through horizontal elongate slots 851 in the slide rail 847 and threaded into a respective side wall 843. The control panel 551 is connected to the slide rails 847 at the sides of the control panel by two: upper screws 857 and two lower screws 859. (0086] As shown sequentially in Figs. 29A-29C, the control panel 551 may be opened to provide convenient access to the various electrical components mounted within the housing 831.

In a closed or upright position, as shown in Fig. 2.9A, the electrical components are: concealed within the bousing 831. To open the control panel 551* the screws 849 holding the slide rails to side walls are loosened. Handles 861 on the control panel 551 may then be used to pull the control panel forward* or in a direction away from the back wall 841, until the screws 849 through the slide rail slots 851 stop further forward movement of the slide rails 847, as shown in Fig. 298. The upper screws 857 connecting the control panel 551 to the slide rails 847 are then removed, allowing the control panel to fee pivoted about an axis extending between the two lower screws 859. In the- open or :han:g-dowh'' position, as shown in Fig.... ':29G, the; electrical, components mounted within the housing 881 are exposed for convenient access and servicing. For example^ the Components mounted on the back side of the control panel 551, including the main controller 507 and associated components* are readily accessible. The; components 'mounted ph the. 'Side While 84 3, including for example the main breaker switches 525* high-limit thermostat -527 'and USB host' adapter: 821, are also readily' accessible. Further* the components mounted on the chassis 845, including for example the transformers 521, contactor device 531 and blower speed/direccion controller 509, are conveniently exposed and oriented in a position for Convenient access.

Without the chassis 845, electrical components would need to be mounted on, e.g., the back wall 841 or the top wall of the lower section 5B. 10087J The chassis 845 provides a vertical mounting surface forward of the back wall 841 and spaced relative to the control panel 551 in its closed position to locate the electrical components mounted on the chassis in a position where an operator may conveniently view, access and service the components When the control panel is open. &amp; primary mounting surface 865 of the chassis 845 is located with respect to the control panel. 551 in its closed position to provide clearance between the electrical components mounted on the chassis and back side of the control panel, and to position the components mounted on the chassis conveniently close to the opening created when the control panel is open. In the illustrated embodiment, the control panel 551 is disposed at an angle from the vertical plane (e.g., 5 to 90 degrees, or more desirably 10 to 70 degrees, or even mors desirably 10-30 degrees! for convenience of use:: arid best view of the operator input 505 (e.g., liquid crystal display touch screen) ,.. However, the control panel 551 may be disposed in a generally vertical orientation. Whether the control panel 551 is disposed at an angle or in a generally Vertical orientation, the distance between the control panel and the primary mounting surface 865 of the chassis 845 is desirably between 2 and 15 in., more desirably between 4 and 12 in,, and even mdfe desirably, between 5 and 9 in. The distance as used herein: means the distance D in Fig:,: 28 as measured· from the:: vertical centerline 8:67 of the front wall 551 in: its closed position and the vertical centerline 869 of the: primary mounting surface 865 of the chassis 845. This spacing enables service personnel to conveniently access components mounted oh the primary mounting surface 865 of. the chassis 845 With standard tools, such as a screwdriver with an 8 in. shaft and blade. The primary mounting surface 865 is desirably positioned no further than :1-0: in. from the back side of the control panel 551 in its closed position to enable Service personnel to use standard tools. The spacing also allows for clearance between the mounted components such that wires connecting the components are not pinched or bent and a minimum clearance is provided for flow of cooling air between the components. Other spacing arrangements than those mentioned above may be used. 100883 The chassis 845 also serves to create a more efficient flow path for cooling air across the electrical components mounted within the housing 831, the cooling flow path being defined by the space between the chassis and the front wail 551. The components are cooled by relatively cool air pulled by the Cooling fan 541 through: an inlet. 871 in the side wall 843. The chassis 845 is configured to decrease the. area of the flow path. Thus, less air is required to effectively cool the components,: and one relatively small cooling: fan 541 may be used: bather than tw©: Or more, fans·, pesirablyy air pulled by the cooling fan 541 does not pass 'through the space between the chassis 845 and the back wall 841. (0089] Figs. 30-3¾ illustrate another embodiment of a blower wheel, generally designated 121*, for circulating gas through the cooking chamber II', and a steam generation and water injection system, generally designated 171', for delivering water to the heated blower wheal 1217 for dispersion into the upper portion 53a* of the air conduit system 53. The blower wheel 121' and the water injection system 171' are similar in many respects to the blower wheel 121 and water injection system 171 described above, and corresponding parts are designated by the corresponding reference numbers, plus a prime designator {'}. In this embodiment, ah even number -of blades 135' are used to enhance balance of the blower wheel 121', and fewer blades are used, creating more space between the blades. The blades 135' do not have water-dispersiοn formations for dispersing water into the cooking chamber like the water-dispersion formations 151 of the blower wheel 121. Water dispersion formations are not: necessary in this embodiment because the water injection system 171* delivers water to a different location bn the blower wheel 121* . In this: embodiment, as shown in Figs, 30 and 32, the components of the injection system 171* are mounted on the top wall 107* of the oven at a location where the injector 173' extends from the top wall down to a position for delivering water for impact against the rotating and heated upper wheel member 131' which, in this embodiment, comprises a circular plate {also designated 131*). Heating of the blower wheel 121' (and thus the upper wheel member 131 '> is accomplished by circulating hot gas ie.g., air) from the cooking chamber 11' over the surfaces of the blower Wheel, which raises the ."temperature of the .'blower;: wheal surf aces above·; the:; boiling point of water for steam, generation'.: By-way csf example:, the injector may be spaced about 0.25 in, above the circular: plate 131 ’ . As a result,: water is'injected oh to: the upward fheing1 Upper surface of the circular plate": 131.1,: where much of the 'water flashes to steam and is then dispersed into the cbqkfttg chairier 11 * through the air conduit system 53,

Water that does hot flash to steam slides to the outside perimeter of the plate 131% as a result of the rotation of the plate/ and is dispersed in the form of small droplets across the hfating elements 71' and onto the walls within the air conduit system 53/ such as the side walls 47 or hack wall 51. Water droplets that do hot initially change to steam slide down the walls 47, 51 to the bottom wall 45, where the water is then evaporated into steam vapor. £0090] The esbodimeat including the blower wheel 1211 and the water injection system 1711 provides several advantages, such as: more efficient steam generation; shielding of water droplets from contacting food product in the cooking chamber 11; and less noise generation. The present embodiment generates steam more efficiently because the water injection system 171' delivers water for impact against the upper surface of the rotating upper wheel member 131 *. The water remains in contact with the upper surface of the wheel member 1.31 * for a longer period of time than it would if injected against the blades 135% and the upper wheel member 131’ has a relatively large surface area (approximately 155 square inches in one embodiment). Thus, the upper wheel member 131' imparts more efficient heat transfer to the water, flashes the water to steam more effectively/ and decreases the amount of water leaving the blower wheel 1:2:1 * without flashing to steam. The present ''embodiment also shields: water droplets: from the .watet:: injection:, system 171' from: entering the cooking chamber 111 through the exhaust 69’ and undesirably affectihg the cooking process. Introduction of water to the suction side 121a’ or even the output side 121b:* of the blower wheel 121 may allow water droplets that do not flash to steam to: enter the cooking:, chamber 11’ through the exhaust 69* and Contact'. the food product in the cooking chamber. In the present embodiment, water that does not flash to steam when it contacts the upper surface of the upper wheel member 131) slides to the outside perimeter of' the plate and is dispersed onto the walls within: the air conduit system 53, such as the side walls 4..7 or hack wail 51. Thus, water that does not flash to steam is moved away from the exhaust 6-91 to avoid contact with the food product in the cooking chamber II*.

As shown in Fig. 32, water generally contacts: the circular plate 1.31’ in the annular region 901, which has no. 'holes through which /liquid"· can pass . The annular· region' 901 is^ bounded by the phantom circular line designated:9Q3 and by the outside perimeter of the plate. The phantom circular line 903 is concentric with the axis of rotation of the plate 131’ and has a radius less than the distance from the center of. the plate to the location on the plate over which the injector 173* is mounted. Further, the present embodiment results in less noise generation because the water impacting the circular plate 131* creates less noise than if the water were impacting the rotating blades 135* or water-dispersion formations 151 {Fig. 3}. 10091] Figs, 33-34 illustrate, in the lower section SB of: the oven 1, another embodiment of a blower wheel, generally designated 231 *, for circulating ghs through the cooking chamber 225> and a water injection system, generally designated 351’, for delivering atomized water to the blower: wheel 291’ for dispersion into the air conduit system 271. The blower wheel 281Λ and the water injection system 351’ are similar in many respects to the blower wheel 281 and water injeetioh system 3;51 described above, and corresponding parts arc designated by the corresponding reference numbers, plus a prime designator (*).

In this embodiment, the blower wheel 281’ lacks the "squirrel cage*’ incioded on the blower wheel 281. The water injection system of this embodiment includes a quick-release: connection between the supply line 38.91 and the injector 355.* , A tab 903 at the end of the supply line 389* is provided for disconnecting the injector 355*, which has an O-ring for creating a fluid-tight seal between the: injector and the supply· line. In this embodiment, the heating elements 311* are located in different positions in the air conduit system 271 below the bofctgffi: wall;

O'? Q r. λ* y ψ [Q092J Having described the invention in detail, it will be apparent that modifications and variations arc possible without departing from the scope of the invention: defined in the appended claims. In this regard, it will be understood that an oven of this invention may have different cooking chamber configurations. By wav of example, the Oven may have only one baking chamber 11 and no proofing chamber 225; or the oven stay have two op more baking chambers 11 stacked one on top of another with ho proofing chamber; or the oven may have one baking chamber and two proofing chambers, Other combinations are possible.

[0093J When introducing elements of the present invention or the preferred embodimentsis) thereof, the articles "a", "an", "the" and "said" are intended to mean that there are one or more of the elements. The terms "comprising", "including" and "having" are intended to be inclusive and mean that there may be additional elements other than; the listed; elements, [00941 In view Of the above, it will be; seen that the several objects of the invention are; achieved: and other advantageous results attained.

[0095J As various changes could be made in the above constructions and methods without departing from the scope: of the invention, it is intended that all matter; contained In the above description and -shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims (20)

1. The claims defining the invention are as follows:

   1. An oven for cooking food, the oven comprising: a cooking chamber for receiving the food, a blower wheel for moving gas in the oven chamber, the blower wheel being rotatable for drawing gas into the blower wheel axially from a suction side of the blower wheel and for outputting gas radially from an output side of the blower wheel, a heater for heating the gas, a water system configured for delivering water to a third side of the blower wheel opposite the suction side, and a recirculation conduit for circulating gas from the cooking chamber back to the cooking chamber, the blower wheel being located in the recirculation conduit.
2. 2. An oven as set forth in claim 1, wherein the blower wheel includes a wheel member and a plurality of blades, the water system is configured for delivering the water to the wheel member, and the wheel member is configured for dispersing the water radially from the wheel member.
3. 3. An oven as set forth in claim 2, wherein the blower wheel is rotatable about an axis of rotation, and the wheel member includes an annular region concentric with the axis of rotation for receiving the water.
4. 4. An oven as set forth in claim 2, further comprising a shaft connected to the wheel member for rotating the blower wheel, the blades being supported by the wheel member for rotation by the shaft.
5. 5. An oven as set forth in claim 2, wherein the wheel member comprises a circular plate.
6. 6. An oven as set forth in claim 1, wherein the water system includes a water tube having an outlet positioned for delivering water to the third side of the blower wheel.
7. 7. An oven as set forth in claim 6, wherein the water tube outlet terminates short of the third side of the blower wheel.
8. 8. An oven as set forth in claim 1, wherein the cooking chamber has an exhaust for exhausting gas from the cooking chamber to the recirculation conduit, the suction side of the blower wheel being adjacent to and facing the exhaust, and the output side of the blower wheel facing transversely with respect to the exhaust.
9. 9. An oven as set forth in claim 8, wherein the third side of the blower wheel faces away from the exhaust.
10. 10. An oven as set forth in claim 1 wherein: the water system comprises a water tube having an outlet at the third side of the blower wheel for delivering water to the third side of the blower wheel, the oven comprises a recirculation conduit for circulating gas from the cooking chamber back to the cooking chamber, the blower wheel being located in the recirculation conduit, the cooking chamber has an exhaust for exhausting gas from the cooking chamber to the recirculation conduit, the suction side of the blower wheel is positioned adjacent to and facing the exhaust, and the suction side of the blower wheel is located between the water tube outlet and the exhaust.
11. 11. An oven as set forth in claim 10, wherein the blower wheel includes a wheel member and a plurality of blades, the wheel member being located between the outlet of the water tube and the exhaust, the outlet of the water tube being positioned for delivering water to the wheel member, the wheel member being configured for dispersing the water radially from the wheel member while the blower wheel is rotating.
12. 12. An oven as set forth in claim 11, further comprising a shaft connected to the wheel member for rotating the blower wheel, the multiple blades being supported by the wheel member for rotation by the shaft.
13. 13. An oven as set forth in claim 1, wherein the blower wheel includes a water receiving region on the third side to which the water system is configured to deliver water as the blower wheel rotates, said water receiving region on the third side being free of blades extending radially away from the shaft to adjacent the output side.
14. 14. An oven as set forth in claim 1, wherein the blower wheel is rotatable about a shaft having an axis of rotation, and the blower wheel includes a water receiving region on the third side to which the water system is configured to deliver water as the blower wheel rotates, the water receiving region including a water receiving surface facing in a direction generally parallel with the axis of rotation of the shaft away from the suction side, the water system being configured to deliver substantially all of said water to said water receiving surface.
15. 15. An oven as set forth in claim 1, wherein the blower wheel is rotatable about a shaft having an axis of rotation, the wheel member is configured to disperse water radially as droplets, and the wheel member is configured to disperse substantially all of said water droplets in a water dispersion plane generally perpendicular to the axis of rotation.
16. 16. A method of operating an oven, the method comprising: rotating a blower wheel in a recirculation conduit of the oven to move gas from a cooking chamber of the oven into the recirculation conduit and back to the cooking chamber, the rotating blower wheel moving the gas by drawing gas into the blower wheel axially from a suction side of the blower wheel and outputting gas radially from an output side of the blower wheel, and delivering water to a third side of the blower wheel opposite the suction side of the blower wheel.
17. 17. A method as set forth in claim 16, wherein the blower wheel draws gas from the cooking chamber into the recirculation conduit from an exhaust in the cooking chamber, and the suction side of the blower wheel is positioned adjacent to and faces the exhaust.
18. 18. A method as set forth in claim 16, wherein delivering the water to the third side comprises delivering the water to a water receiving region on the third side as the blower wheel rotates, said water receiving region on the third side being free of blades extending radially away from the shaft to adjacent the output side.
19. 19. A method as set forth in claim 16, wherein rotating the blower wheel comprises rotating the blower wheel about a shaft having an axis of rotation, and delivering water to the third side of the blower wheel comprises delivering substantially all of said water to a water receiving region on the third side as the blower wheel rotates, the water receiving region including a water receiving surface facing in a direction generally parallel with the axis of rotation of the shaft away from the suction side.
20. 20. A method as set forth in claim 16, wherein rotating the blower wheel comprises rotating the blower wheel about a shaft having an axis of rotation, and further comprising dispersing water radially as water droplets from a wheel member of the blower wheel and wherein dispersing said water droplets comprises dispersing substantially all of said water droplets in a water dispersion plane generally perpendicular to the axis of rotation.