Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF THE INVENTION
While there have been provided a wide variety of
heating chambers for use as bake ovens, and the like, there .
~ema~ns a problem in bake ovens of the prior art which attempt
to bake articles generally uniformly from all~angles so as to .
ac~ieVe uniform color of the baked product. Of course, this
~s an important requisite in the ba~ing of pretzels, and the like.
Pu~ther,.prior bake ovens attempting to obtain even product
color on all surfaces required relatively high rates of fuel
combustion to achieve a design BTU capacity.
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SUMMARY OF THE INVENTION
It is, therefore, an important object of the present
invention to provide heating apparatus for a pretzel baking oven~
and the like, which overcome the above mentioned difficulties,
effectively affords a highly uniform baking action from all angles
to achieve the desired evennessof product color, and further
effects considerable savings in fuel-costs by producing relative-
ly high B.T.U. per unit of fuel.
It is still another object of the present invention to
provide a heating apparatu~ having the advantageous character-
istics mentioned in the preceding paragraph which is extremely
simple in construction for economy in manufacture, it is extreme-
ly easily serviced ~o effect substantial savings in maintenance
cost3, and is of extremely high thermal efficiency to produce
considerable economy in cost of fuel.
Other objects of the present invention will become
apparent upon reading the following specification and referring
to the accompanying drawings, which form a material part of this
disclosure.
The invention accordingly consists in the features of
construction, comblnations of elements, and arrangements of parts,
which will be exemplified in the construction hereinafter des-
cribed and of which the scope will be indicated by the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is side elevational view showing a baking oven
constructed in accordance with the teachings of the present
invention, being broken for accommodation to the drawing space.
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Flgure 2 is a sectional plan view taken generally along
the line 2-2 of Figure 1.
Figure 3 is a sectional plan view taken generally along
the line 3-3 of Figure 1.
Figure 4 is a sectional elevational view taken generally
along the line 4-4 of Figure 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now more particularly to the drawing, and
specifically to Figure 1 thereof, a heating apparatus in the
nature o~ a bake oven is there generally designated 10, and
includes an elongate housing or chamber 11 which may be of gener-
ally con~tant, rectangular cross section, say having an elevated,
generally horizontal top wall 12, a pair of generally vertical,
parallel spaced side walls 13 and 14 depending from opposite
sides of the top wall, and a generally horizontal bottom wall 15
extending laterally between lower edges of the side walls and
longitudinally coextensive with the top wall. The oven chamber
or housing 11 may be spaced over a nether support or floor, as
by suitable floor engageable, depending legs 17.
A~ noted hereinbefore, Figure 1 illustrates the oven 11
in sections to accommodate drawing space, the left-hand end of
the upper section being broken away, as at 19, and being the
upstream or inlet end, while the ~ight-hand end of the lower
section is bro~en away at 20, which designates the downstream or
outlet end o~ the chamber. In con~entional manner a product
conveyor or belt 21 has an upper run 22 extending longitudinally
through the cham~er 11, spaced between the upper and lower
chamber walls 12 and 15, ~or carrying product longitudinally
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through the conveyor, as in baking. The conveyor 21 may include
a lower or return run 23 passing upstream beneath the chamber 11
for reentry into and downstream movement through the interior of
the chamber.
While the embodiment illustrated and described herein is
particularly directed to the baking of pretzels, and has been
primarily developed for the pretzel, it is appreciated that the
instant invention is capable of many vàried applications, all of
which are intended to be comprehended herein.
In addition, the chamber 11 may be provided at spaced
locationsalong its length with suitable openable closures, access
opening~ or doors, as at 25, 26, 27, 28 and 29. The openable
closures 25-29 may all be located on one side of the chamber 11,
say on the side wall 14, adjacent to the bottom wall 15, to
thereby affoxd convenient access into the lower interior regions
of the chamber for cleaning and removal of debris and collected
waste. The chamber walls 12-15 may be of any suitable construc-
tion, having de~ired insulating qualities, and may be structur-
ally reinforced or braced, as desired, all without departing from
the teaching~ of the present invention.
At longitudinally spaced locations interiorly along the
upper region of the chamber 11 there are mounted therein a
plurality of upper heating elements 31, 32, 33 and 34. m e upper
heating elements 31-34 are generally soplanar, in a plane spaced
over the upper conveyor run 22. A lower series or row of heat-
ing elements is arranged interiorly of the chamber 11, including
several elements 36, 37, 38 and 39. The lower heating elements
36-39 are genèrally coplanar with each other, in a plane beneath
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359
the upper conveyor run 22. It will be observed that the horizon-
tally spaced, adjacent pair of upper heating elements 31 and 32
are located in spaced relation with respect to each other, as are
the lower horizontally spaced adjacent pair of heating elements 36
and 37. Further, the upper and lower heating elements are in
alternating relation with respect to each other, so that the lower
element 36 is beneath the space between the adjacent upper heating
elements 31 and 32, while the upper heating element 32 is over the
space between adjacent heating elements 36 and 37. This relation-
ship of alternate upper and lower heating elements may advanta-
geously continue throughout the chamber 11. For example, the
lower heating element 37 is spaced between and beneath the space
between adjacent upper heating elements 32 and 33; the upper
heating element 33 being spaced between and over the space between
adjacent lower heating elements 37 and 38; the lower heating
element 38 being spaced between and beneath the space between
adjacent upper heating elements 33 and 34; and the upper heating
èlemënt 34 being spaced between and over the space between ad-
jacent lower heating elements 38 and 39~ Such alternate spaced
relation, while advantageous, is not absolutely essential at all
time~. For example, there may be prevailing reason to place an
adjacent pair of upper or lower heating units without an inter-
mediate heating unit of the other row.
The upper heating unit 31 is best seen in Figure 2 as
including an elongate hollow tube or pipe 41 of metal or other
suitably heat conductive material. The elongate tube or pipe 41
is advantageously of a sinuous or undulant configuration, includ-
ing a plurality of Pipe portions 42, 43 and 44 extending
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~ 1100359
generally transversely across the longitudinal direction or path
of movement of conveyor 21. ~ore specifically, the pipe or tube
portions 42-44 may be generally straight, and in general parallel-
ism with and substantial coplan~rity with each other, lying in a
plane spaced over parallel to the upper conveyor run 22. Inter-
posed in fluid communication between the adjacent ends of parallel
tube portions 42 and ~3 is an arcuate interconnecting portion 45,
while a similar arcuate interconnecting portion 46 is interposed
in fluid com~unication between the adjacent ends of tube portions
43 and 44. The other end portion 47 of tube portion 42 may extend
exteriorly of the chamber ll, as through side wall 42, where it
is provided with a flame producer or burner 48. The burner 48
may be conventional and is provided with suitable oxygen and fuel
supply means, and control elements, not shown in the drawing.
Remote from the burner end portion 47 of tube or pipe 41, the
distal end of pipe portion 44 is provided with an outlet gate or
discharge closure 49, say swingable about a mounting hinge 50 and
openable to afford interior access to the pipe 41. Also provided
on the pipe portion 44 are a series or row of outlet openings or
apertures 51, which are located in and open in the plane of the
parallel pipe portions 42-44, and face away from the pipe portions
42 and 43.
Provided in the chamber side wall 13, proximate to the
heating unit 31, may be a removable wall closure or access opening
52 affording convenient access to the heatinq unlt 31, as for
cleaning or other maintenance. The hinged end gate 49 may serve
to relieve excess pressure within the heating pipe 41, and may
also be openable to afford con~enient access in maintenance.
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; 11003S9
The heating element 32 may be essentially identical to
the heating element 31 and arranged in a facing spaced relation
with respect to the latter. More specifically, the heating
element 32 may include an undulant or sinuous elongate pipe or
tube 61 having generally coplanar, parallel spaced portions 62,
63 and 64 extending transversely above and over the upper con-
veyor run 22, and generally coplanar with the parallel pipe
portions 42-4~ of heating element 31. The heating unit tube or
pipe 61 may include intermediate or connecting portions 65 con-
nected in fluid communication between adjacent ends of tubeportions 62 and 63, and an intermediate connecting portion 66
connected in fluid com~unication between adjacent ends of tube
portions 63 and 64. The tube portion 62 extends to an end portion
67 which is provided with a flame producer or burner 68, and the
remote end of tube 61 is provided with a pressure relief valve
or closure 69 hingedly connected to pipe portion 64, as by hinge
70 for swinging movement of the release valve into and out of
its normally closed position. In addition, the outer tube portion
64 is provided along its outer side with a row or series of outlet
openings or discharqe holes 71 which lie in and open generally
into the plane of the coplanar pipe portion 62-64. Further, the
discharge or outlet holes 71 of element 32 are located in facing
spaced relation with respect to the discharge or outlet holes 51
of the element 31. Thus, the products of com~ustion from heating
elements 31 and 32 are expelled qenerally coplanar into meeting
engagement with each other in the space over heating element 36.
In th~ region between heating elements 31 and 32, the
impinging combustion gases creates fluid turbulence for effectively
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11003S9
heating product on the conveyor 21. A stack or removal conduit 72
may be mounted on the chamber top wall 12, say between facing,
impinging heating elements 31 and 32. Also, an access opening 73
may be provided in the side wall 13 for ease of access to the heat-
ing element 32.
The additional upper heating elements 33 and 34 are respec-
tively similar to each other and hereinbefore described heating
elements 31 and 32. In particular, heating element 33 is general-
ly horizontally coplanar with and spaced downstream from heating
element 32, includlng a pluarality of generally parallel tube
portions 72, 73 and 74 substantially planar with each other, being
connected in series relation by intermediate arcuate tube portions
75 and 76 and having one end region 77 of tube portion 72 provided
with a flame producer or burner 78. The distal end portion of
heating element 33, namely the remote end of tube portion 74 is
provided with a swingable closure or pressure relief valve 79
suitably hinged, as by hinge 80. The downstream side of tube
portion 74 is formed with a row or series of spaced outlet openings
or apertures 81 generally coplanar with the several tube portions
72-74 for discharging generally horizontally downstream from and
generally coplanar with the heating element 33.
The heating element 34 is similar to the heating element
33, being disposed horizontally generally coplanar with the latter
and spaced therefrom generally downstream within the chamber 11.
In particular, the heating element 34 ma~ include a plurality of
generally parallel tube portions 82, 83 and 84 extending trans-
verseIy across the path of conveyor 2I, being connected in series
fluld communication by arcuate connecting portions 85 and 86.
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1~ 359
The downstream tube portion 82 has its end portion 87 remote from
connecting portion 85 connected to a flame producer or burner 88,
and the distal end of the heating element 34 is provided on tube
portion 84 with a ~wingable closure or pressure reIease valve 89
suitably swingable as by a hinge 90. The tube portion 84 is pro-
vided on its upstream side with a series or row of spaced outlet
apertures or openings 91 for discharging fluid generally horizon-
tally upstream, coplanar with the heating element 34.
Suitable openable access doors may be provided adjacent
to respective heating elements 33 and 34.
The lower heating elements 36 and 37 are respectively
similar to upper heating elements 31 and 32, but located in alter-
nate relation therewith, being spaced below and beneath the upper
run 22 of conveyor 21. More part~cularly, the lower heating
elements 36 and 37 are both generally horizontal and coplanar
with each other, the upstream heating element 36 being located
beneath the space bet~een upper heating elements 31 and 32, and
including a plurality of generally parallel tube portions 102, 103
and 104 disposed in ~oplanar relation with each other and serial-
~0 ly connected in fluid communication by intermediate arcuate tube
portions 105 and 106. Upstream tube portion 102 extends remote
from connecting portion 105 laterally to an end portion 107, to
which is connected exteriorly of the adjacent side wall 114 a
flame producer or burner 108. The distal end of the heating
element 36, being the end of tube portion 104 remote from
connecting portion 106 is provided with a swingable closure or
pressure release valve 109, and the tube portion 104 is formed
on its downstream side with a series or row of spaced outlet
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openings or apertures 111 for discharging horizontally generally
in the plane of heating eIement 36.
Downstream from heating element 36 beneath the upper
run 22 of conveyor 21 is the heating element 37, which is located
beneath the space between upper heating elements 32 and 33. The
heating element 37 is similar to heating element 32, including a
plurality of generally parallel transverse tube portions 112, 113
and 114, serially connected together by arcuate intermediate tube
portions 115 and 116, having on the downstream end 117 a flame
producer or burner 118, and having on the upstream end a normally
closed pressure release valve 119. Further, the upstream trans-
verse tube portion 114 is formed on its upstream side with a row
or series of through openings or outlets 121 for discharging com-
bustion products generally horizontally coplanar with the heating
element 37 toward the discharge stream of combustion products
from heating element 36.
While the previously described heating elements 31, 32,
33, 34, 36 and 37 have been arranged in opposed facing pairs to
achieve certain effects sometimes highly desirable, it is not
essential that all heating elements be arranged in facing pairs.
That is, the pair of heating elements 31 and 32 have their dis-
charge outlets 51 and 71 in facing relation for impinging of
the combustion products discharged from these heating elements
to ach~eve a turbulent convection in the space between ~he heat-
ing elements. This is similarly achieved by the facing relation
between upper heating élements 33 and 34, as well as the facing
pair of lower heating elements 36 and 37. T~us,- as described
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110(~359
the heaters 31 and 32 provide combined heating effects of radia-
tion, as from their sinuous tubular configuration, as well as the
heating action of the turbulent gaseous combustion products. The
additional pairs of heating elements 33 and 34, and 37 are similar-
ly effective to achieve this above described combinative heating
action, whlch has been found highIy advantageous in producing a
uniform baking color with minimum energy requirements.
However, by way of illustration it will be seen that the
unique heating elements of the present invention need not be
arranged in the impinging relationship described hereinbefore,
witness heating elements 38 and 39. Heating element 38 may in-
clude a plurality of generally horizontal, parallel tube portions
122, 123 and 124 arranged in horizontal coplanarity with each
other, each extending transversely of and beneath the upper con-
veyor run 22. The tube portions 122-124 are serially connected
together in fluid communication by intermediate connecting por-
tions 125 and 126, the downstream end of heating element 38 termin-
ating in an end portion 127 connected to a flame producer or
burner 128. The upstream end of heating element 38 may be pro-
vided with normally closed pressure release valve or closure 129,and the upstream ~ide of tube portion 124 is formed with a series
or row of through apertures or outlet openings 131 for discharging
generally horizontally and coplanarly with the heating element 38.
However, it will be noted that the discharge openings 131 of
heating element 38 do not impinge upon the discharge products of
another heating element, the next adjacent upstream heating
element 37 facing upwardly away from the downstream heating
eIement 38.
.; 110~3S9
Similarly, the lower heating element 39 is beneath the
upper conveyor run 22, spaced downstream of the lower heating
element 38 and upper heating eIement 34. The heating element 39
may include a plurality of generally parallel tube portions 132,
133 and 134 arranged in horizontal coplanarity and extending
transversely of and beneath the upper conveyor run 22. The trans-
verse tube portions 132-134 are serially connected in fluid
communication by intermediate arcuate connecting portions 135 and
136. The upstream tube portion 132 extends to an end region 137
away from the connecting portion 135 to a flame burner 138, while
the downstream tube portion 134 remote from connecting portion 136
is provided with a normally closed pressure release valve 139.
Also, the downstream tube portion 134 is formed along its length
with a row or series of through apertures or outlet openings 141
for discharglng combustion products generally horizontally and
coplanarly with heating element 39, downstream therefrom and away
from the next adjacent lower heat~ng element 38. m us, the down-
stream adjacent pair of lower heating elements 38 and 39 face
away from each other ~o as to prevent their discharging combustion
products from impinging against each other and achieving the
hereinbefore described turbulent convection. Such orientation of
burners may.be desirable under certain circumstances, as when
such turbulence iR unnecessary, or when radiation from above or
below i~ desirable without turbulence, Also, the heating elements
need not be employed in pairs, but may be utilized individually
to achieve the combined radi~tion and convection current heating
as desired.
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From the foregoing it is seen that the heating apparatus
of the present invention is highIy versatile in producing both
radiant and convection heating, in desired sequential relation,
both with and without gaseous turbulence, which is capable of
producing pretzels and llke baked products having uniform and
even color all over, and simultaneously effecting substantial
economies in operation by producing rélatively high B.T.U.'s with
relatively low energy consumption.
Although the present invention has been described in some
detail by way of illustration and example for purposes of clarity
of understanding, it iq understood that certain changes and
modifications may be made within the spirit of the invention.
