Method and apparatus for searing and cooking food products

A method and apparatus for efficiently making grill marks on both sides of a plurality of food products while simultaneously cooking the plurality of food products. The food products may include hamburgers, chicken breast, soy products, etc. A continuous grilling belt transports products along a path of conveyance in which heat, speed, and other variables are controlled. The product is automatically turned over during the conveyance period. The food product may be produced in industrial quantities.

BACKGROUND OF THE INVENTION 
The present invention relates to the field of cooking food products and, 
more specifically, an apparatus and method that will be used in an 
industrial process. 
Food products are often pictorially advertised, in photographs and 
television, as having grill stripes or score marks on the surface. In 
fact, although tremendously appealing to the eye, it is very difficult to 
achieve these marks in a commercial manner. This is due to the fact that 
the cooking area of the grill or barbecue therefore is uniformly hot. 
Therefore, the steel members forming the grill marks are not necessarily 
much hotter than the surrounding air space. 
SUMMARY OF THE INVENTION 
An aspect of the preferred embodiment includes a grilling machine which 
scores a plurality of food products comprising: a burner for supplying a 
thermal energy to the plurality of food products; a grill conveyor 
assembly having a belt which has an upper and a lower portion; and wherein 
said lower portion passes through a fire from said burner and said upper 
portion scores the plurality of food products. 
Another aspect of the preferred embodiment includes an apparatus 
comprising: a first grilling belt which scores a first side of a plurality 
of food products; a second grilling belt which scores a second side of the 
plurality of food products; wherein the second grilling belt is located in 
a linear position relative to the first grilling belt. 
Another aspect of the preferred embodiment includes an apparatus which 
simultaneously cooks and scores a plurality of food products comprising: a 
first grilling machine comprising: a first burner for supplying thermal 
energy to said plurality of food products; a first grill conveyor assembly 
having a belt which has a first upper and a first lower portion; said 
first lower portion passes through a fire from said first burner and said 
first upper portion cooks and scores the food product on a first side; a 
second grilling machine comprising: a second burner for supplying thermal 
energy to the plurality of food products; a second grill conveyor assembly 
having a belt which has a second upper and a second lower portion; and the 
second lower portion passes through a fire from the second burner and the 
second upper portion scores the food product on a second side. 
Another aspect of the preferred embodiment includes an apparatus 
comprising: a first means for simultaneously cooking and scoring a food 
product; a second means for simultaneously cooking and scoring a food 
product; wherein said second means is located in a linear position 
relative to the first means. 
Another aspect of the preferred embodiment includes a method comprising: 
conveying a plurality of food products through a first grilling machine; 
simultaneously cooking and scoring said plurality of food products with a 
first side down; turning said plurality of food products over onto their 
second sides as the food product travels from the first grilling machine 
to a second grilling machine located in a linear relationship to the first 
grilling machine; conveying said plurality of food products through said 
second grilling machine; simultaneously cooking and scoring said plurality 
of food products with a second side down.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIGS. 1-11 of the drawings depict the preferred embodiment of the present 
invention for purposes of illustration only. One skilled in the art will 
readily recognize from the following discussion that alternative 
embodiments of the structures and methods illustrated herein may be 
employed without departing from the principles of the invention described 
herein. 
Currently, in industrial food processing plants, due to the concern with 
contamination, the United States Department of Agriculture (U.S.D.A.) does 
not allow use of the same instrument for raw and cooked products. This 
regulation has forced many manufacturers to buy stationary grilling 
machines and transfer product at different stages of cooking to separate 
machines. This creates a non-uniform product with uneven grill marks due 
to the movement of the product while cooking. This method of cooking 
depends on the instinct of the person who is grilling which in turn 
creates overcooking and uneven cooking which also creates a loss in yield 
of product. 
The grilling machines 102 and 104 of the preferred embodiment as shown in 
FIG. 1 have eliminated the above deficiencies by controlling the heat 
through self-modulating gas burners, by controlling the speed of the 
conveyor belt which transports the food product through the grilling 
machines, and by only moving the food product or plurality of food 
products once to flip them over during processing so the food product 
stays in the same spot on the grilling (or grill) ribs while it is carried 
through the first and second cooking tunnels 140, 142. 
FIG. 1 illustrates a utility or backside elevational view of the preferred 
embodiment with insulated panels removed in accordance with a preferred 
embodiment of the present invention. Reference Numerals 102 and 104 show 
industrial high capacity continuous grilling machines. The grilling 
machines may be used either alone or in combination depending on if a 
grill mark is desired on only one side (one grilling machine) or both 
sides (two grilling machines) of the food product. The grilling machines 
102 and 104 have the same exact structure except that the lower assembly 
of grilling machine 104 has been set at a lower height. The second 
grilling machine 104 is located in a linear position relative to the first 
grilling machine 102 as shown in FIG. 1. Reference numeral 120 represents 
a food product or plurality of food products which may include hamburgers, 
chicken breasts, soy products, imitation meat, meat, fish, vegetables, and 
any other type of food products. The food product 120 may be cooked in 
industrial or commercial quantities and at a rate exceeding 1,000 pounds 
(lbs.) per hour. Therefore, although only a single food product 120 is 
being shown in FIG. 1 it is to be understood that a plurality of food 
products may be continually fed through the combined grilling machines 
100. 
The food product 120 is initially conveyed to the infeed side of the first 
grilling machine 102 on a conveying device 122. The first grilling machine 
102 is made up of a first lower assembly 106, a first conveyor assembly 
108, and a first upper assembly 110. The second grilling machine 104 is 
made up a second lower assembly 107, a second conveyor assembly 109, and a 
second upper assembly 111. 
The first lower assembly 106 includes a first powerful gas burner 130 
spraying flames into first fire chamber 132. The first fire chamber 132 
contains a damper 128 which rests on the lower frame 150 and which directs 
the flames in an upward direction. The second lower assembly 107 includes 
a second powerful gas burner 131 spraying flames into second fire chamber 
134. The second fire chamber 134 contains a damper 129 which rests on the 
lower frame 152 and directs the flames in an upward direction. The first 
and second fire chambers 132 and 134 are spaced above the bottom insulated 
panel (not shown) which is attached to the frames 150 and 152 so as to 
create an air insulation layer between the fire chamber and the bottom 
insulated panel and provide for double insulation. The use of separate gas 
burners allows the first grilling machine 102 to be run at a different 
temperature than the second grilling machine 104. The first and second 
fire chambers 132 and 134 are each made up of a fire chamber frame (1002 
in FIG. 10). The first and second fire chambers 132, 134 rest inside the 
first and second lower frames 150 and 152. The first and second fire 
chambers are not attached to the lower frames 150 and 152, but are 
detachable modules. The first and second fire chambers hang by hooks (702 
as shown in FIG. 7) which extend the length of each of the grilling 
machines on the first and second lower frames 150 and 152. Because the 
first and second fire chambers are not attached to the lower frame they 
are able to expand as the temperature in the first and second fire 
chambers increase. 
The burners 130 and 131 are controlled by a temperature controller 
(reference numeral 800 which is shown in FIG. 8) which is modulating a gas 
valve 972 (shown in FIG. 9) and creating uniform heat inside first and 
second cooking tunnels 140 and 142. The burners 130 and 131 do not create 
a direct flame on the food product 120, but instead are directed at first 
and second conveyor assemblies 108 and 109. The gas train and control 
components of the burners 130 and 131 are completely sealed. (Note that 
ashes may be allowed to build up in the first and second fire chambers 
which would create a smokey or barbecue flavor effect on the food product 
as the ashes are burned and burned again). 
The first and second lower assemblies also include supports 173 and 175 
which allow for the adjustment of the height of each of the grilling 
machines 102 and 104. 
The first and second lower assemblies 106 and 107 further include first and 
second electric motors and gear reducers 330 and 332. The use of two 
separate driving devices allows the first grilling conveyor belt 310 to 
run at a different speed than the second grilling conveyor belt 312. 
Therefore, the cooking speeds of the food product 120 may be controlled 
with a great degree of accuracy. 
The first lower assembly 106 further includes a stainless steel frame 150 
which provides support for the first conveyor assembly 108 and first upper 
assembly 110 of the grilling machine 100. The second lower assembly 107 
further includes stainless steel frame 152 which provides support for the 
first conveyor assembly 108 and first upper assembly 110 of the grilling 
machine 100. The stainless steel frames 150 and 152 may be made from 
2".times.2" stainless steel tubing. 
The first conveyor assembly 108 includes a first grill (or grilling) belt 
310 and the second conveyor assembly includes a second grill (or grilling) 
conveyor or belt 312. The first grilling belt 310 includes a first lower 
portion 310A and a first upper portion 310B. The second grilling belt 312 
includes a second lower portion 312A and a second upper portion 312B. The 
simultaneous cooking and scoring of the food product occurs on the first 
and second upper portions 310B, 312B. First and second burners 130 and 131 
are located in fire chambers 132 and 134 which contain dampers to spread 
the heat evenly. 
The first and second burners 130 and 131 are positioned so that no direct 
flame is directed at the food product 120 to keep the yield high and not 
dry out the food product 120. The burners 130 and 131 shoot flames through 
the fire chambers 132 and 134 to heat the first and second lower portions 
310A, 312A of the grilling belts. The grilling belts 310 and 312 are each 
made up of a plurality of grilling ribs 310 (as shown in FIG. 3) which are 
travelling through the direct flames 130A, 131A of the burners 130, 131. 
The grilling ribs may reach temperatures of approximately 600 to 1,000 
degrees Farenheit. The grilling ribs 310 absorb the heat of the direct 
flames 130A, 131A which will simultaneously cook and score the food 
product 120 when the grilling ribs 310 are in the first and second upper 
portions 310B, 312B of the grill conveyors 310, 312. The first and second 
conveyor lower portions 310A, 312A protect the food product 120 from the 
direct flame as it is being conveyed, cooked, and scored on the first and 
second conveyor upper portions 310B, 312B so that at no time does a direct 
flame have to come into contact with the food product. 
The first cooking tunnel 140 extends above the first grilling conveyor belt 
310 and the second cooking tunnel 142 extends above the second grilling 
conveyor belt 312. The first and second cooking tunnels 140 and 142 are 
insulated tunnels formed by 1.5.times.1.5 inch stainless steel tubing 
(1102 in FIG. 11) and removable insulated two inch thick panels (918A-D 
shown in FIG. 1 and FIG. 11) which allow for access to the machine while 
cleaning. The grilling ribs 310 and the cooking tunnels 140 and 142 allow 
the food products to be cooked at temperatures in the range of 
approximately 350 to 400 degrees Farenheit. 
Grilling belt 310 of grilling machine 102 is set at a greater height using 
supports 173 than grilling belt 312 of grilling machine 104 in the 
preferred embodiment so that the food product 120 which has a first side 
down in the first section 102 will flip and then fall onto the second 
grilling belt 312 so that grilling marks may be achieved on the second 
side of the food product 120 as it travels through the second grilling 
machine 104. 
The first conveyor assembly 108 further includes conveyor sprockets 320 and 
322 which turn the first grilling conveyor belt 310. The second conveyor 
assembly 109 further includes conveyor sprockets 324 and 326 which turn 
the second grilling conveyor belt 312. 
As discussed above, the first upper assembly 110 includes panels 918A and 
918B which allow access for cleaning to the cooking tunnel 140 as shown in 
FIGS. 1 and 11. The first upper assembly further includes a first duct 
exhaust 160 containing a damper (not shown) which removes fumes from the 
cooking tunnel 140. The second upper assembly 111 includes panels 918C and 
918D which allow access for cleaning to the cooking tunnel 142. The second 
upper assembly 111 further includes a second duct exhaust 162 which 
removes fumes from the cooking tunnel 142. The panels 918A-D are mounted 
on stainless steel struts 1102 which rest in U-shaped channels 920 located 
in the conveyor assemblies as shown in FIG. 9. The housing cover 930 may 
also rest in the U-shaped channels located on the conveyor assemblies. 
Reference numerals 170 and 171 represent steam nozzle sprayers for adding 
humidity (i.e., controlled live steam) during cooking which are controlled 
by a steam valve (not shown) and wet bulb sensor (not shown). The steam 
nozzle sprayers may extend across the path of the food product. The 
ability to add humidity to the cooking tunnels 140 and 142 prevents the 
drying out of the food product and leads to an increased product yield. 
Reference numeral 172 represents an infra-red sensor for checking 
temperature of the finished food product 120 and triggering an alarm if 
the product is undercooked. If the alarm is sounded the operator will be 
signalled to increase the set up temperature of the grilling machine. Due 
to an ability to control heat and speed, in an alternative embodiment, the 
grilling machine 100 may be used to only create grill marks on uncooked 
food that will later be cooked in an oven or fully cooked. 
Reference numeral 180 represents an outfeed conveyor device for delivering 
the finished food product 120. 
FIG. 2 illustrates a front elevational view of the preferred embodiment 
with insulated panels 210 in place. 
FIG. 3 illustrates a fragmentary, enlarged front elevational view of the 
first grill conveyor assembly 108 in accordance with the preferred 
embodiment. The food product 120 is travelling on the grilling belt 310 as 
it nears roller or sprocket 322 right before the food product falls onto 
the lower positioned second grilling conveyor 312. A shaft 328 drives the 
sprocket 322. The first grilling conveyor 310 is made up of a chain 330 
and grill ribs or links 332. The chain 330 may be A-1 stainless steel #60 
chain and the grill ribs 332 may be made of 1.5 inch by 1.5 inch stainless 
steel angles. The upper portion of the grilling belt 310 is supported by 
an upper chain guide 340 which travels over a stainless steel tubing 342 
which holds both sides of the grilling belt 310. The lower portion of the 
grilling belt 310 rides on a lower chain guide 344. A screw (not shown) 
may be used to adjust the tension in the chain. 
The distance between links 332 when they are between the rollers in a first 
link position is shown by L1 and may be approximately 0.66 inches. The 
distance between links 332 when they are nearing roller 322 in a second 
link position is shown by L2 and may be approximately 0.75 inches. The 
distance between links 332 when they are turning over the roller 322 in a 
third link position is shown by L3 may be approximately 1.16 inches. The 
distance between links 332 when they are turning over the roller 322 may 
be approximately 1.20 inches. As the distance between the links spread, 
the food product 120 is gradually losing the attachment to the grilling 
belt 310 and falls onto the second grilling belt 312. As the food product 
120 falls, it turns over so that the second side may be grilled. Although 
the action of the ribs 332 is shown with respect to roller 322, the same 
type of movement will occur in grilling belt 312 as the food product 120 
from grilling belt 312 to outfeed conveying device 180. 
In an alternative embodiment, the distances L1, L2, L3, and L4 may be 
varied according to the pitch of the chain which is chosen. 
FIG. 4 shows an enlarged side elevational view of the first grill conveyor 
assembly 108 in accordance with the preferred embodiment. Chain links 410 
which are part of chain 330 contain attachment pieces 412 which are 
connected to ribs 310 through fastening devices 416. Each fastening device 
416 is made up of a nut 510 and bolt 512. Spacers 420 keep the upper chain 
guide 340 and lower chain guide 344 an even distance from grilling 
conveyor wall 430. 
FIG. 5 shows an enlarged side elevational view of a grilling rib 310 in 
accordance with the preferred embodiment. The grilling rib 310 is attached 
to a chain link 412 as discussed above. 
FIG. 6 shows a side view of the first lower assembly 106 and first conveyor 
assembly 108 of the first section 102 of the grilling machine 100. The 
first conveyor assembly 108 is supported on the stainless steel frame 150 
of the lower assembly 106. There is no attachment between the first 
conveyor assembly 108 and the lower assembly 106 to allow the conveyor to 
expand from the intense heat. The first conveyor assembly 108 sits 
completely free on the frame without bolts or being welded with 
approximately 0.25 inch clearance from both sides. The stoppers 610 
prevent the first conveyor assembly 108 from sliding or moving on the 
frame. The stoppers 610 are located in front of the conveyor. 
FIG. 7 shows an outfeed view of the first lower assembly 106 and first 
conveyor assembly 108 of the first section 102 of the grilling machine 100 
highlighting the capability of the fire chamber 132 to expand. First fire 
chamber 132 rests on 2.times.2 inch angles 702 which rest freely on the 
stainless steel frame 150 with approximately 0.25 inch clearance on both 
sides to allow the first fire chamber 132 to expand. 
FIG. 8 shows a control panel 800 of the griller 100. Reference numeral 801 
is a light indicator for indicating power into the griller 100. Reference 
numeral 802 is an emergency stop button which cuts power when pressed and 
resets when pulled out. Reference numeral 803 is an inverter drive light 
which indicates when conveyor is running. Reference numeral 804 is the 
inverter start button which is pushed to start conveyor and reference 
numeral 805 is the inverter stop button which is pushed to stop conveyor. 
Reference numeral 806 is a feed zone temperature controller which shows 
set-up temperature and actual temperature at the same time and controls 
modulating gas valve which is controlling the heat in the feed zone. 
Reference numeral 807 is an on/off switch for powering the temperature in 
the feed zone controller. Reference numeral 808 is the inverter speed 
control dial which controls the speed of the conveyor. Reference numeral 
809 is a discharge zone temperature controller which shows set up 
temperature and actual temperature simultaneously and controls modulating 
gas valve which is controlling heat in discharge zone. Reference numeral 
810 is an on/off switch which is powering temperature controller in 
discharge zone. Reference numeral 811 is the inverter speed monitor which 
shows speed of belt. Reference numeral 812 is a product temperature 
controller which is coupled to sensor 172 to show temperature of finished 
product and set-up of temperature for finished product. Reference numeral 
813 is a switch to power the product temperature control. 
FIG. 9 shows a side view of the second section 104 of the preferred 
embodiment from line Z--Z in FIG. 1. As previously discussed, reference 
numeral 152 represents the frame of the grilling machine 104. Reference 
numeral 910 represents a drive mount. Reference numeral 912 represents a 
drive truft to store electric wires and prevent them from getting wet 
during a washdown period. Reference numeral 914 shows a drive which 
provides force to the conveyor belt. Reference numerals 935 show angles 
which support the conveyor assembly 109 on the lower frame 152. 
As previously discussed, reference numeral 917 shows an adjustable panel 
which assists in keeping the steam from leaking out from the cooking 
tunnels. The panel 917 may be adjusted to the approximate height of the 
food product 120 which is being cooked. Reference numeral 950 represents a 
burner cover. Reference numeral 972 shows a self-modulating gas valve and 
gas train which controls burner 134. The self-modulating gas valve will 
automatically correct itself to adjust the temperature in the cooking 
tunnels (especially during a "walking" time period). As previously 
discussed, reference numerals 173 show supports or leveling legs for 
adjusting the height of the grilling machines. Reference numeral 980 
represents a cleaner drawer plate which may be pulled out to be cleaned 
and washed down. Reference numeral 982 represents an expansion bearing 
which will let the shaft expand during the cooking period. Reference 
numeral 983 is a bearing which does not expand during heating. Reference 
numeral 962 shows a cleaning brush located above the cleaning drawer 963 
which may prevent the build up of carbon on the edges of the grilling 
ribs. 
FIG. 9 also shows a driving chain 986 for driving the grilling belt. The 
driving chain 986 is contained in a driving chain guard 985 which contains 
perforations 987 which allow the driving chain 986 to be sprayed and 
lubricated without having to remove the guard 985. 
FIG. 10 shows a perspective view of the fire chamber frame 1052 for the 
first grilling machine 102. The fire chamber frame 1052 rests inside the 
lower frame 152. Reference numeral L represents the length of the frame 
1052 which may be approximately 69 inches and reference numeral W 
represents the width of the frame 1052 which may be approximately 31.0 
inches. The fire chamber frame is furnished with 14 # (gauge) stainless 
steel panels that may be removed on one side of the fire chamber in order 
to allow access to the fire chamber for cleaning and maintenance. 
The grilling machines 102 and 104 may also be equipped with a fire system 
which may be used to quickly extinguish fires which occur. 
The method and operation of the grilling machines 102 and 104 will now be 
discussed. The food product 120 enters the grilling machine on the first 
conveyor belt 310 and is transported through the first cooking tunnel 140. 
As discussed above, the lower grilling ribs 310 have been absorbing heat 
from the hottest part of the fire in the fire chambers 132 and 134. 
Therefore, the grilling ribs 310 create grill marks in a very short time. 
During the rest of the passage through the first section 102 the marking 
and cooking on a first side of the food product 120 occurs. The food 
product 120 is being grilled on the first side by the heat from the ribs 
310 and the ribs 310 are creating the grill marks on the food product 120 
in a very short time. When the food product 120 reaches the end of the 
first section 102, the first side is done. If grill marks are desired on 
only one side of the food product, then the process will be completed at 
this point. The temperature of the grilling machine 102 may be set so that 
the food product is thoroughly cooked and scored one side. 
However, if grill marks are desired on both sides of the food product, the 
process continues in the second grilling machine 104. The food product 120 
turns over to a second, unscored side by falling from the higher level of 
the first conveyor belt 310 to the lower level of the second conveyor belt 
312 in the second grilling machine 104. The food product 120 then travels 
through the second section 104 being grilled and marked on the second 
side. At the end of the second grilling machine 104, the food product 
travels out through the outfeed conveyor 180 which removes the product 
from the grilling machine 100. 
Advantages of the preferred embodiment include a food product which has 
even grill marks on both sides of the products. 
Another advantage of the preferred embodiment is that since it may made 
almost entirely of stainless steel so that it can be hosed down during 
cleaning. 
Another advantage of the preferred embodiment is that electrical components 
are completely sealed in N.E.M.A. 4X type enclosures. 
Another advantage of the preferred embodiment is that it will meet U.S.D.A. 
approval. 
Another advantage of the preferred embodiment is that it may handle over 
1000 pounds of food product per hour. 
Another advantage of the preferred embodiment is that no direct flame to 
the product keeps the yield high and does not dry out the food product. 
Another advantage of the preferred embodiment is that the lower assembly, 
conveyor assembly, and upper assembly are not attached and may therefore 
expand as is required by the intense heat. 
The foregoing is to be understood as being in every respect illustrative 
and exemplary, but not restrictive, and the scope of the present invention 
disclosed herein is not to be determined from the Detailed Description, 
but rather from the claims as interpreted according to the full breadth 
permitted by the law. Therefore, it is to be understood that the 
embodiments shown and described herein are only illustrative of the 
principles of the present invention and that various modifications may be 
implemented by those skilled in the art without departing from the scope 
and spirit of the invention.