US 3168642 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Feb. 2, 1965 J. sAvlo 3,163,642
ELECTRICALLY HEATED FORCED AIR CIRCULATION OVEN Filed Jan. 24, 1965 4 Sheets-Sheet l I 1 iiliil W INVENTOR. afoa'ipu @134 V0 ATTORNEYS J. SAVIO 3,168, 642 ELECTRICALLY HEATED FORCED AIR CIRCULATION OVEN 4 Sheets-Sheet 2 Feb. 2, 1965 Filed Jan. 24, 1963 ATTORNE X5 I- -l mw z m Wm M y J w W NMN WW w Feb. 2, 1965 J. SAVIO 3,168,642
ELECTRICALLY HEATED FORCED AIR CIRCULATION OVEN Filed Jan. 24, 1963 4 Sheets-Sheet 3 ATTORNEYS Feb. 2, 1965 J. s'Avlo ELECTRICALLY HEATED FORCED AIR CIRCULATION OVEN Filed Jan. 24, 1963 4 Sheets-Sheet 4 mill/[11071111101712 INVENTOR JOSEPH 624 1/10 ATTORNEYS United States Patent Ofilice avin, Flo l h a corpora Ll GMCED This invention relates to improvements in ovens, and, in particular, relates to an improved electrically heated oven provided with forced air circulation such as disclosed in my pending application Serial No. 222,283, filed September 10, 1962, now Patent No. 3,127,499, granted March 31, 1964, for Electrically culation Oven.
One object of the invention is to provide an electric oven wherein the heating elements are concealed within the walls, and having improved means for maintaining uniform air ilow and uniform temperature throughout the oven.
Another object of the invention is to provide an improved electric oven having improved means for sealing the doors and thereby ensuring uniformity of heat and minimum heat loss.
Another object of the invention is to provide an oven which is economical to use and which produces unifornn ity of halting, roasting and the like.
in accordance with a preferred embodiment of the invention, the oven comprises a casing having a peripheral wall and end walls, one of the end walls having doors for access. Electric heating means are provided within the peripheral wall of the oven, which transmits the resulting heat into the interior space of the oven. A bafiie plate is mounted in the casing in relatively closely spaced parallel relation to the end wall opposite the wall having the doors. The peripheral edge of the baffie plate is relatively closely spaced from the peripheral wall. The battle plate has a central opening. A high speed convector or fan is positioned and operative to draw air through the central opening of the bafile plate toward the adjacent end wall and then in a counterilow between the bariie plate and the end wall and back around the peripheral edge of the baffle plate. The battle plate has additional openings which are sized and positioned for how through them toward the end wall of air drawn by the air flow etween the baffle plate and the adjacent end wall. The result is to provide a uniform flow of air through the center of the casing rearwardly and through the baflie plate, with the counterfiow being set up around the periphery of the casing.
in accordance with the invention, means are provided in the oven for receiving horizontal racks in parallel relation, for support of food to be cooked. The size of the fan opening is such that in order to ensure maximum use of the oven, with racks at available levels for cooking a maximum amount of food, at least one racl; must be positioned opposite the fan opening. The considerable size of the fan opening could then cause an undue current of air to be drawn over the racl; and through the fan opening. Therefore, in accordance with the invention, disrupter elements are placed across the fan opening in such relationship to the opening and to the rack opposite the opening as to break up the air flow over such rack and prevent undue cooling of the food on the rack opposite the fan opening.
As another important feature of the invention, an improved door gasket assembly is provided for the face frame of the oven so as to ensure adequate seal ng of the door. Further, the gasket element is designed and assembled so that it may be readily replaced when it wears from the heat of the oven. This reduces the need for Heated Forced Air Cir- Feb. 2, 1965 23 skilled servicing of the oven and reduces the amount of service time of the oven.
Other objects and advantages of the invention will become apparent from the following description, in conjunction with the annexed drawing, in which a preferred embodiment of the invention is disclosed.
In the drawing,
FIG. 1 is a perspective view of the oven in accordance with the invention, the oven doors being shown open;
FIG. 2 is a vertical longitudinal section of the oven, on line 2-2 of FIG. 1.
1G. 3 is a section on line 33 of FIG. 2.
FIG. is a section on line 4-4 of FIG. 2, the doors being shown closed.
FIG. 5 is a fragmentary section on line 55 of FIG. 4.
FIG. 6 is a fragmentary section on line 66 of FIG. 4.
FIG. 7 is a fragmentary section on line 7-7 of FIG. 2.
Fl 8 is a fragmentary front elevation, broken away and to enlarged scale, of the face frame of the door opening of the oven.
FIG. 9 is a fragmentary exploded sectin on line 9-9 of FIG. 8.
FIG. 10 is a fragmentary perspective view of a tray for insertion in the oven.
The oven casing Upon particular reference to FIGS. 1, 2, 4, 6 and 7 of the drawing, it will be noted that they show an oven 14) open at the front and having rear wall 12 and a peripheral wall structure consisting of top wall 13, side walls 14 and 140 and bottom wall 15. Top door 1'7 and bottom door 18 are normally received within oven front opening 16 against face f ame 95. The doors have a coplanar, vertical closing position in which their adjacent edges are sealed by gasket assembly 99 (FIG. 4-) and in which the edges of the doors are sealed against further gasket assembles 99 mounted upon theface frame of door opening 16 (PEG. 7). Said doors 17 and 13 are laterally pivoted respectively at their top and bottom to the side walls 14 and 14%, so as to permit them to be pivoted between their opening and closing positions. Handle 19 is fixed to the outside of door 17 for use in opening and closing the door.
Glass windows 2'3 and 21 and glass windows Windows 21 and 23 are in vertical alignment in the door closed position. Windows 2% and 22 are also in vertical alignment, with the windows 20 and 22 being located respectively on the opposite side of the vertical center line of doors 1'7 and 18 from the windows 21 and 22. Window 20 is located above the level of window 21, although with the lower edge of window 2%) extending below the upper edge of window 21. Window 22 is located above the level of window 23, although with the lower edge of window 22 extending below the upper edge of window 23. These windows are optionally rectangular, and the result is to permit viewing of the interior of oven 13 substantially at every vertical level, while at the same time providing a minimum of glass area with resultant dissipation of heat.
Rear wall 12 has a rear wall panel 12a, front wall panel 12b and intermediate wall panel 120. Wall 13 has upper wall panel 130, lower wall panel 131') and intermediate wall panel 13c. Wall 14 has outer wall panel 140, inner Wall panel 145 and outer and inner intermediate wall panels and 14 Wall 15 has lower wall panel 15a, inner wall panel 15:; and intermediate wall panel 150. Wall 140 has outer wall panel l itla, inner wall panel 1 1% and outer and inner intermediate wall panels 1490 and 14%,". These wall panels are generally rectangular, and the panels of each wall are parallel to each other. Corresponding panels of adjacent walls are interconnected to are provided in door 17,
2?. and 23 are provided in door 13.
oneness form inner oven chamber 2, heating compartment sur rounding oven chamber 2, insulation compartment 25a surrounding heating compartment Mill: and outer compartment 94 holding moving parts and providing a dead air space.
Inner oven chamber 2 has rear wall 12b, top wall 135, bottom wall 15b and side walls 14b and Mill), and is substantially square. The front edges of the top, bottom and side walls are coplanar. Wall 12b extends above wall 13b, below wall 15:! and outwardly of walls llfid and 14b respectively. Wall 13d extends upwardly from wall 131) near the front thereof. Wall 15d extends downwardly from wall 15b near the front thereof. Walls rash and 14h respectively extend outwardly from walls 14% and 14b. The walls 13d, lldilh, 3150! and 14-11 are coplanar and join with each other to form the front wall of the heating compartment 24a. Wall 130 extends between the upper edge of wall 13d and the upper edge of wall 12]).
Wall 150 extends between the lower edge of wall 150? and the lower edge of wall 121;. Wall ld-j extends between the outer side edge of Wall 1411 and the side edge of Wall 1212. Wall ldllj extends between the outer side edge of wall 14% and the side edge of wall 12b. The walls 130, lddc, 15c and Me meet each other to complete the wall of compartment 24a.
A plurality of electric heating elements 2d are located within the compartment 24a, each of these elements 2% being generally U-shaped with longitudinal legs and a front connection portion 24b. Bracket 24c connects each pair of legs of each heating element to the outer wall of compartment 24a. Optionally, there are three such heating elements in each side of compartment 24a, one in the top and two in the bottom, as best shown in FIG. 4. The legs of the heating elements 24 extend through wall 1212 (FIG. 7) and are there connected in any suitable electric circuit (not shown). 7
The face frame 95 includes wall 132 which extends upwardly from the front edge of wall lllband wall 15@ which extends downwardly from the front edge of wall 15b. Face frame 95 further comprises sidewall 1 d which extends outwardly from the front edge of 141) and side wall Mild which extends outwardly from the front edge of wall 14%. Walls 13c, c, Md and 149d are coplanar. Insulation compartment a includes the aforesaid walls of face frame 95. Insulation compartment 25a also includes side walls 140 and l lfi-c respectively connected to the outer side edges of walls 14d and 14nd. Further, insulation compartment 25a includes top wall "13a which extends rearwardly from the top edge of wall 13c, and bottom wall 15a which extends rearwardly from the bottom edge of wall 15c. Wall 120 serves as the rear wall of compartment 25a and extends between walls 13a and 15a near the rear ends thereof. It will be apparent, without extended showing, that wall 120 similarly extends to walls 140 and 14th: to complete the enclosure of compartment 25a. Compartment 25a is filled with any suitable insulation 25, which, by way of example, may be conventional fiberglass insulation. Walls 15a and 13a extend rearwardly of wall 12c and are connected by rear wall 12a, which serves asthe rear wall of air insulation compartment 94. Although not shown, it will be readily apparent that wall 12a also connects side walls 14a and 140a of compartment 94. To complete compartment 94,'wall 14r extends forwardly and perpendicularly from wall 14d intermediate the side edges thereof. Wall 14hr extends forwardly and vertically from wall 149d intermediate the side edges thereof. (The face frame 95 includes the portions of walls ldband Mild inwardlyof walls 14; and 14hr.)
13h and wall 1401-. Walls 14% and 142 respectively Wall 13 has side front extensions- 13g and 1311, as shown in FIG. 1. Wall 1dr connects extend outwardly of walls was and lie. Wall 14a; extends between the outer side edge of Mile and a side edge of wall 12a. Wall extends between the side edge of wall 14c and the other side edge of wall 12a. Wall 149 extends between walls 13:; and En. Wall lea also extends between walls 136! and 35a. Although not shown, it will be apparent that wall 15 has extensions corresponding to extensions 13g and 13h extending to walls 14:: and EL E-fie respectively and between walls Mr and Mo on the one hand and l t-fir and jl ltl'a on the other hand.
Any suitable base 89 underlies and supports bottom wall 15 and in turn rests upon any suitable horizontal support.
It will be understood that the panels can be formed and connected by any suitable means, for example, in some instances by bending of sheet metal and in other instances by welding or other securing of sheet metal.
The door construction As shown in 5188. l, 2 and 4-, each door 17 and is of hollow core, rectangular metal construction.
The interior space of each door is filled with insulation 3d of fiberglass and the like. Handle 19 is in the form of a laterally extending bar connected by studs 19a adiacent the respective ends thereof to the front panel of upper door 1.7 Lateral pivots 31 extend out of the sides of the respective doors 1.7 and 18, adiacent the remote lateral edges thereof. As shown in detail in FIG. 6 for the upper door, the construction being similar for the lower door, the pivot pins extend through suitable in walls and respectively, and extend through bearing blocks 32 respectively mounted upon the front faces of walls Add and fetid respectively. Pins 31 further extend outwardly of panel 140 and 14% respectively. One of the pins 31 of lower door 18 extends into the space between panels 114a and his, where one end of arm 34 is mounted on said pins 31 (PEG. 4). When door is is opened, the free end of arm 34 strikes block 33 mounted between panels 14a and Me as shown in FIG. 6.
On the'other side, the respective pins 31, which extend laterally outwardly of panel 149e, are coupled for movement in unison by means best shown in FEGS. 4 and 6. Sprocket wheel as is fixedly mounted upon upper pin 31, outwardly of partition panel 149e, by means of hub d1. Sprocket wheel 42. is mounted upon the correspondlower pin 31, by means of hub 41a. Said sprocket wheels 4d and are in general vertical alignment. Upper sprocket chain 43 extends around the top of upper sprocket wheel it Bottom sprocket chain 4-4 extends around the bottom of bottom sprocket wheel 42. lvietal tape 55 is connected at one end thereof to one end of chain 43. Metal tape 4-6 is connected at one end thereof to the other end of upper sprocket chm'n 43. Turnbuckles d7 and 48 respectively connect the other ends of the tapes 45 and to the respective ends of chains 44 in cross-over relation. As a result, if the upper door 17 is moved by means of handle 5.9 from its closed position, toward its open position, sprocket 4%) is moved in counterclockwise direction, the sprocket 42 is correspondingly moved in clockwise direction, so that the lower door 18 is also opened. Conversely, closing of door 17 causes closing of door 18. Arm 34 extends generally rearwardly when the doors are closed. Opening of door 18 moves arm 3 until it extends generally upwardly and strikes stop 33, stopping further opening movement. At this point, optionally, door 13 is horizontal.
An important feature of this construction is that it is possible to have different sprocket and chain ratios, so that selected movement of the lower door requires a different movement of the upper door. Specifically, the teeth of the sprockets may bear such ratios, with corresponding ratios of the chain openings, that movement of the upper door more than degrees is required to produce the optional 90 degree opening movement of the bottom door, as shown in FIG. 3. Thus, the ratios may be selected so that the upper door moves about 105 degrees in order to bring the lower door to its final 90 degree movement. This can be accomplished because there is not a continuous chain, the chains instead being connected by the tapes and turnbuckles. The tapes can be secured to the chain ends and turnbuckles by any suitable pivot means which need not be described in detail. The turnbuckles 47 and 48 are conventional and need not be described in detail. Generally speaking, any suitable turnbuckle may be employed, but by way of example, the turnbuckle 48 may have a central collar 49 into which screws 50 extend, these screws 50 being respectively connected to the chain end and tape end. As a result, by appropriate turning of collar 49, the tension may be adjusted.
Forced draft fan and bafii'e construction Generally planar, generally square baflle plate 50 is mounted in the interior of oven in relatively closely spaced parallel relation to the rear vertical end wall panel 125. As best shown in FIG. 7, headed studs 52 are fixed to plate 50 adjacent the corners thereof, by any suitable means, and extend rearwardly thereof. A spacer collar 51 is mounted on each stud 52 and spaces the baffle plate 50 from wall 12b. Stud 52 extends through any suitable opening in wall 125, and retaining nut 53 is screwed upon the threaded rear end of stud 52 against wall 1212.
Panel 50 has a central circular opening 54. Longitudinally extending drive shaft 55 is aligned axially with the center of hole 54 and extends through a sleeve bearing 56 which extends through and is mounted in an opening of wall 12c. Sleeve bearing 56 is secured at its front end to wall 121). Shaft 5'5 extends through an appropriately located opening of wall 12!; and forwardly thereof. Shaft 55 also extends rearwardly of wall 12c into the space between walls 120 and 12a, Where pulley 57 is mounted upon shaft 55. Fan belt 53 on pulley 57 extends downwardly through a bottom opening of wall and hence below wall 15. Electric motor M, which may be connected to any suitable source of electric power (not shown) is mounted by a bracket 53a on the bottom of wall 15'. Motor M has an output shaft 58b, and pulley 580 is mounted upon shaft 58]). Belt 58 also extends around pulley dfic, so that the motor M drives shaft 55.
Squirrel cage fan or pump 61, which has a diameter slightly greater than that of opening 54, is mounted upon shaft 55 between baffle plate and wall 12]) and may have any suitable peripheral wall 6.3 with slots 64 and fins 64a so as to suck in air through the front opening and through opening 54, and to exhaust said air between the fins outwardly of the periphery of the fan.
The bottom peripheral edge portion of baffle flange 50 may optionally be bent forwardly slightly at 65a. The free edges of bafile plate 50 are relatively closely spaced from the respective panels 14b, 14%, 1332 and 155, which may together be considered as the peripheral wall of the inner chamber 2 of oven 10.
The effect of the above-described arrangement is to cause the air movement means (the fan) to draw air through the central opening 54 towards the end Wall panel 121) and then in a counterflow between baffle plate 54 and end wall panel 122) and bacl: around the peripheral edge of a bathe plate :50. Bafile plate 50 has additional openings 66 sized and positioned for flow through said additional openings 65 toward said end wall panel 12b of air drawn by the air flow between bafile plate 50 and end end wall panel 12!). Putin other terms, these openings 66, located radially outwardly of opening 54, result in a suction being produced through said openings by the abovementioned counterilow of the air, thereby drawing air rearwardly through the openings 66. This diffuses the air movement rearwardly through the bafiie plate and prevents it from being concentrated centrally. The effect is to produce a more uniform air movement, both the main movement rearwardly through the main portion of the oven and the counterflow around the periphery thereof.
Preferably, the openings 66 are alranged in concentric rings A and B. The openings of each ring are substantially equally spaced circumferentially. In the embodiment illustrated, ring A has eight openings respectively located at 12:00, 1:30, 3:00, 4:30, 6:00, 7:30, 9:00 and 10:30. Ring B has twelve openings, including four respectively at 12:00 oclock, 3:00, 6:00 and 9:00 oclock and eight other openings located so that the twelve openlogs are equally spaced circumferentially, as clearly shown in FIG. 3. Openings 66 of ring A are located slightly outwardly of opening 54. Openings 66 of ring B are located adjacent the outer periphery of bathe plate 50. At the four corners of baflle plate 50, at which the openings of ring B are more spaced from the periphery, additional openings 66:: and 66b are provided. These openings are circular, the openings 66a at two diagonally opposed corners being smaller than the intermediate corner openings 6612. This is because an optional electrical lamp 660 is mounted in a socket in wall 12b and extends forwardly thereof in line with opening 6612, as shown in FIGS. 3 and 2. The electrical connections of the lamp socket are omitted.
Reference is made to FIG. 3, which is substantially to scale of a working model, to show the particular arrang ment of the holes in bafile plate 50.
In order to disrupt the air flow, and further improve the uniformity of air flow, horizontal bars 70 are mounted upon the front face of baffle 50, extending across opening 54. Said bars are secured to the baffle plate by any suitable means. Each said bar 70 is substantially T-shaped in vertical cross section and has a front laterally coextensive rib 70a to produce the T-shape. As shown in PEG. 3, the bars 70 extend chordally with respect to opening 54, and are approximately equidistant from the center of the opening.
On each side of opening 54, plate 50 has vertically spaced and aligned, apertured lugs 201 struck forwardly therefrom. A vertical rod 200 passes through the apertures of each set of lugs on the respective sides of opening 54, the lugs being suitably aligned to permit this construction. Any suitable retaining nuts 200a may be threaded upon the correspondingly threaded upper ends of rods 200, above and below the upper lug 200, in each instance, to retain the rods in place.
The racks As shown in FIG. 10, rack is defined by a peripheral, generally rectangular tubing frame A series of longitudinally extending rods 82 are laid over the front and rear sides of the tubing frame 31 and secured thereto by any suitable means. The side legs 81a of frame 81 are received in channels 83 fixed to the respective side panels 14b and 1401'). There are two such channels 83 in coplanar relationship at each level upon which it might be desired to place a rack. Each channel 83 has a side portion fixed to the wall and upper and lower arms The side tubing leg 81a is slidably received between the arms 83a, with the width of frame 81 being sufficient to ensure that the respective frame sides 81a will be received in the respective channels. One or more spring clips 84 are fixed to the top of each tubing side 81a. As shown in FIG. 10, said clip 84 is made of a strap of flexible and resilient metal having its ends fixed by any suitable means to the frame and having its center portion 84a upwardly bowed. When the rack is inserted in place, spring clip 84a frictionally engages the upper channel arm 83a, thereby ensuring that the rack is held frictionally in place with out possibility of rattling under the high velocity of air flow within the oven. Rods 200 serve as stops to rearward rack movement to maintain it spaced from battle plate 50.
As shown in FIGS. 2 and 3, the spacing of the channels 83 is such as to ensure maximum utilization of the interior chamber 2 of the oven, when all trays are in place. i
, with a face frame 95 within that opening.
Preferably, the lowest pair of channels 33 is located just above the bottom wall 15b of chamber 2. There is preferably uniform spacing between successive rack levels,
with the spacing between the top rack and the top chamer wall 131; being approximately equal to the spacing between successive lower racks. Preferably, the spacing between successive racks is less than the diameter of opening 54.
It will be noted that with all racks in position, one of the racks is located at approximately the level of the center of hole 54, with the rack immediately above being located just above the upper level of hole 54-, and with the rack immediately below being located at approximately the level of the bottom of holest. Accordingly, each of the disrupter bars 7b is located between successive racks and bridges the opening 5 3 between successive racks. It will be apparent, therefore, that when food is placed upon a respective rack below a respective bar 79, the food is horizontally opposed by a respective bar 7i Without the bar '79, a considerable draft would be created 'directly over the food causing a high volume flow of air over the food and through the opening 54. The eflect of the bar '78 is to break up the air flow, creating eddies and reducing the effective opening size, so as to prevent excessive air flow directly over the food upon the rack in question. The effect of this is to prevent undue cooling or other unsatisfactory effect upon food located upon a rack opposite the large opening 5d. The ultimate effect, accordingly, is to ensure even baking of all of the contents of the oven. The effect of the flange or rib 73%: is a to tend to cause deflection of air above and below the bar 7e, rather than mere reverse flow which would occur if the surface of the bar were completely flat.
The gasket assembly The gasket assembly 9?, shown generally upon door 17 and upon face frame 95 in FIGS. 1, 2 and 7, shown in detail in FIGS. 8 and 9.
As previously stated, the oven has a front opening in 17 and 18 are received within the opening 16 and in closed position lie against the front of the face frame 95. A gasket assembly 99 extends along each side of the face frame 95, against the front face thereof, so that four gasket assemblies 95 together extend completely around the face frame and provide a complete seal against the rear faces of doors 1? and 13 when they are closed. The further gasket assembly 99, as previously stated, is mounted upon the lower edge of door if] so as to' provide a seal against the upper edge of door 18.
Each gasket assembly 19 consists of a bar 110 for attachment to the surface to be sealed, by means of a sealant 126, and a gasket 1% removably mounted upon bar 11%. For convenience, the description will be with reference to the face frame, but it will be apparent that essentially the same description applies with respect to door 317.
Bar 11%) is elongated so as to run the full length of the edge portion which is to be sealed, and is generally rectangular in shape. Bar 11d has two depe ng parallel bosses 111 and H2 coextensive in length and spaced from each other. The boss 112 extends to one side 11%;:
of bar 110. The boss 111 is spaced from boss 112 and intermediate boss 112 and the other side 11% of bar 118. Boss llll is spaced from side lhb. Side 11% is preferably given a coextensive radius lillc at the junction of side fifth and the upper surface or face llitld of bar 110. Groove 112 is formed in the upper face 110d of Groove 12 In other words,
bar ill) and extends the full length thereof. is of inverted T-shape in cross section.
the upper portion 112a of groove 112 is of reduced width,
and the bottom or base portion 11% of groove 112 is widened. The groove portion 112:: is centered with respect to the side edges of groove 11212. Groove H2 is located adjacent the block side 119b, or in other words, is offset with respect to the center line of block 110.,
At selected intervals, holes may be formed through The doors L block ill and screws 125 may be extended through such frame so as to secure block lit? to the face frame. For example, screws 125 may be self-tapping screws. The head of screw 125 is countersunk in the usual way so as to be flush with surface 11 .907. The sealant 12b" is interposed between block Hill and face frame 95, in such a way as to maintain block lib spaced from the face frame, and to fill in all the space between block 11% and face frame 95. Sealant 121%) may be putty or any other suitable sealant material and may be applied by any suitable means. The sealant material extends under both of the bosses 111 and 112 and extends to the undersurface of the main portion of the block 11%, and also extends completely between the side edges of the block. The material 1245 has low thermal conductivity for minimum conduction of heat to gasket 1%.
Gasket is in the form of a flattened tube coextensive in length with block lit). Gasket 1% is flexible and-resilient and may be made of any suitable synthetic rubber material or the like. Gasket 1% has a flat bottom wall 161 and a convex upper wall N2, the bottom of which is closed by wall lt l. A generally T-shaped flange 193 depends from wall it'll adjacent one side edge thereof. Specifically, the flange W3 includes a leg ltld which depends from wall fill and which is slightly thicker than wall ltll. At the'bottom of leg The, further flanges Hi5 and 186 extend outwardly therefrom in coplanar relationship. The width of flange 1555 is less than the width of flange 166, and is approximately equal to the increase in width on one side between groove 112a and groove ll2b. The total width of flanges iii-5 and 1% is about equal to the width of groove 5112b. The width of flange 104 is slightly less than the width of groove 112a. The'total height of flange 1% is approximately equal to the total height of groove 112.
In assembly, the T-flange 193 is receivedwithin. the T-groove 112, with the bottom surface of wall 1 2 1 overlying and resting against surface lltld. In the assembly, the flanges M35 and are lockingly received within groove 1125, with this being the main locking action between the two parts. 'The flange 1494 then extends freely through groove 112a. It will be apparent that in use, the door striking the convex wall 162 compresses same, to ensure a tight seal.
It will be apparent that the gasket 1% may be readily readily disassembled from block lit and replaced when The action of the fan and of the doors having been described under their respective headings, the overall operation of the oven need not be further summarized. It will be sufiicient to point out that the uniform air flow through the interior of the oven results in a uniformity of temperature throughout the oven. It has been found possible to cook meat satisfactorily at a low temperature of 200-225 F. with a pan of water maintained in the oven, with a roast shrinkage as low as five to six percent. At the same time, the oven is highly more efficient and economical to operate than a convection gas oven. Because of the construction features, including the gasket construction, the oven has been found to be particularly durable under service conditions, and to require a minimum of service time.
While a preferred embodiment of the invention has been disclosed, and various possible changes, omissions and additions have been indicated, it will be apparent that various other changes, omissions and additions may be made in the invention without departing from the scope and spirit thereof.
What is claimed is:
1. In a electric oven of the type described, a chamber having a rear wall and a peripheral side wall, a bafile plate in said chamber adjacent and parallel to said rear wall and spaced from said peripheral wall and having a relatively large central opening, a blower behind said baflle operative to cause air to flow rearwardly through said central opening and to counterflow around said baflle plate and forwardly, means releasably supporting racks in said chamber in horizontal spaced relation with each rack extending across said chamber, each rack adapted to receive food thereon for cooking, at least one rack positioned for food thereon to oppose and be aligned with said central opening, and a horizontal bar on said baffle across said central opening and opposing said food, said bar sized and shaped to block and reduce air flow over said food.
2. In an electric oven of the type described, a chamber having a rear Wall and a peripheral side wall, a baffle plate in said chamber adjacent and parallel to said rear wall and spaced from said peripheral wall and having a relatively large central opening, a blower behind said baflie operative to cause air to flow rearwardly through said central opening and to counterflow around said bafiie plate and forwardly, means releaseably supporting racks in said chamber in horizontal spaced relation with each rack ex tending across said chamber, one rack at about the level of the lower edge of said central opening, another rack across approximately the center of said central opening,
another rack approximately at the upper level of said central opening, each rack adapted to receive food thereon for cooking, and a pair of horizontal bars on said bafile across said central opening and respectively between respective ones of the aforesaid designated three racks, each said rack bar sized and shaped to block and reduce air flow through said central opening between the racks adjacent thereto, each said bar thereby preventing undue cooling of food on a rack in opposition to said central opening.
3 In an electric oven according to claim 2, each said bar having a coextensive boss of reduced height across the front thereof, said boss being centered between the upper and lower edges of said bar.
References Cited in the file of this patent UNITED STATES PATENTS 1,657,205 Ehrgott Jan. 24, 1928 2,242,335 Yoxsimer May 20, 1941 2,490,076 Maxson Dec. 6, 1949 2,491,420 Scott Dec. 13, 1949 2,663,916 Millman Dec. 29, 1953 2,906,620 Jung Sept. 29, 1959 2,957,067 Scofield Oct. 18, 1960