Multiple pass linear oven
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A multiple pass linear oven for heating food products. The linear oven has multiple passes that run through the oven vertically in order to shorten the length of the linear oven, while still maintaining the amount of time the food product is spent inside the oven. The use of multiple levels of conveyor in one linear oven saves space and money. A second multiple pass linear oven has different stations performing different functions. Each station is set up along one conveyor. This allows the food product to remain on one conveyor while being treated three different ways.

Nothum Jr., Robert G. (Springfield, MO, US)
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Primary Examiner:
Attorney, Agent or Firm:
JONATHAN A. BAY (1736 E Sunshine Ste 410, SPRINGFIELD, MO, 65804, US)
I claim:

1. A multiple pass linear oven for heating food products having: multiple passes carrying the food product through the oven vertically; an entry conveyor that allows the linear oven to switch from multiple to single pass; and, multiple stations for providing different functions to the food product as it passes through each station.



This application claims the benefit of U.S. Provisional Application No. 60/965,688, filed Aug. 21, 2007.


The invention generally relates to large scale food processing lines and, more particularly to a multiple pass linear oven.

A number of additional features and objects will be apparent in connection with the following discussion of preferred embodiments and examples.


There are shown in the drawings certain exemplary embodiments of the invention as presently preferred. It should be understood that the invention is not limited to the embodiments disclosed as examples, and is capable of variation within the scope of the appended claims. In the drawings,

FIG. 1 is a front elevational view of a first embodiment of a multiple pass oven in accordance with the invention;

FIG. 2 is a front elevational view of a second embodiment of multiple pass linear oven in accordance with the invention; and,

FIG. 3 is a side elevational view of the multiple pass linear oven of FIG. 2 in accordance with the invention.


FIG. 1 shows a first embodiment of a multiple pass linear oven. The multiple pass oven is a linear convection oven for heating food products. The food products pass through the oven on a series of continuously run conveyor belts. The conveyor belt enters in one side of the oven, runs through the length of the oven and then exits out the opposite side of the oven. As the conveyor runs through the oven, the heat from the oven heats the food product.

Prior art linear convection ovens have one straight line conveyor belt for carrying food product through the oven. The longer the food products need to be heated the longer the linear oven must be.

FIG. 1 shows a linear convection oven with three levels or passes. Each pass is a conveyor belt which carries the food product though the oven. There is a top pass, middle pass and bottom pass. The top pass runs left to right, the middle pass runs right to left and the bottom pass runs left to right.

The food product enters the oven on an entry conveyor. The entry conveyor carries the food product up to the top pass. The top pass runs the length of the oven. The top pass ends at the end of the oven. As the food product travels along the top pass it reaches the end and falls. The food product falls and lands on the middle pass which is right below the top pass. The middle pass then takes the food product in the other direction, since the middle pass runs right to left. The middle pass carries the food product through the oven again and brings the food products to the beginning of the bottom pass. As the food product reaches the end of the middle pass it falls off and land on the bottom pass which again runs left to right to the end of the oven, eventually leading out of the oven. The food product exits the oven on the bottom pass.

Although FIG. 1 shows three passes any number of passes may be used as long as it is an even number in order to bring the food product in and out on different sides of the linear oven. For the larger food product company a multi-pass linear oven with five, seven or more passes may be more desirable. While a smaller company may need only three passes. It depends on the amount of food product passing through the oven.

It is an object of the invention that the multiple pass linear oven save space and therefor save money. Because the multiple passes run vertically through the linear oven, the linear oven can be shorter in length. Just like a building with multiple floors takes up less land. If you were to take the length of the multiple passes in the linear oven and stretch them out in a straight line, the linear oven would be three times as long. The fact that floor space is saved means money is saved as well. Not only is floor space saved but the linear oven is cheaper to produce since less materials are needed to produce it because it is shorter in length.

It is a further object of the invention that the multiple pass oven have the option of becoming a single pass oven as well. The entry conveyor has two positions, up or down. The entry conveyor can enter the oven at the top pass in the up position or the bottom pass in the down position. For the multiple pass function the entry conveyor would be in the up position. To make the oven a single pass oven the entry conveyor would be in the down position. This would bring the food product to the bottom pass. The food product would travel through the entire length of the oven on the bottom pass and then exit the oven. This would be useful if the food products did not need to be heated as much because the food product would be in the oven for a shorter amount of time. This creates a two in one linear oven.

FIGS. 2 and 3 show a multiple pass linear combination oven. This linear oven is comparable to FIG. 1 except the food product passes through three stations while staying on the same conveyor system. Each station has a different function and does something special to the food product passing through it.

The first station is the steam and hot air convection oven. The steam and hot air station is a convection oven which warms up the food products traveling along the multiple pass. Fans from above heat up the air in the oven which in turn heats up the food product on the conveyors. The food products enter the first station the same way as described in FIG. 1, on the entry conveyor. This station is also multiple pass station as described in FIG. 1 as well. FIG. 2 shows three passes carrying the food product through the station while the bottom station continues to run the entire length of the linear oven, even though any number of passes may be used. After the food product travels the on the top and middle passes and then lands on the bottom pass, the food product travels along the bottom pass and is lead through to the second station.

The second station is the impingement oven. The impingement oven has a high flow rate of hot air from both above and below the food product. The air flow is directed onto the food to quickly and effectively heat the food product at a higher temperature than the convection oven in station one. As the food product exits the second station, it enters the third station.

The third station is the searing and branding unit. The searing unit sears the outside of the food products with an open flame above and below the food product. The branding unit produces grill or other markings on the outside of the food product. There is a conveyor belt that runs above, parallel to the bottom pass that the food product is traveling on. This top conveyor belt is heated and has special markings on it dependant upon what the user desires. As the food travels along the bottom pass, the top conveyor, running the same direction, smashes the food product down imprinting the markings on top of the food product. So, for example, hamburgers running along the bottom pass would be slightly smashed down by the top conveyor having grill marks. These grill marks will transplant to the hamburgers so that the hamburgers will look like they were cooked on a grill.

It is an object of the invention to provide a linear oven with a combination of multiple stations while allowing the food product to remain on the same conveyor system. Any number of stations may be used with each station doing any number of different functions such as bake, broil, steam, brown, sear or roast.

The linear ovens also have a clean in place system and an automatic hood lift or door and touch panel controls. Thermal oil or indirect has heating delivers heating across the full width and length of the cooking belt, this insures a quality cooked product with superior yields.

The invention having been disclosed in connection with the foregoing variations and examples, additional variations will now be apparent to persons skilled in the art. The invention is not intended to be limited to the variations specifically mentioned, and accordingly reference should be made to the appended claims rather than the foregoing discussion of preferred examples, to assess the scope of the invention in which exclusive rights are claimed.