US1561390A - Continuous-conveyer bake oven - Google Patents

Description

Patented Nov. 10, 1925.

UNITED STATES PATENT OFFICE.

JAMES C. WOODSON, OF EAST PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC 8:; MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

CONTINUOUS-GONVEYER BAKE OVEN.

Application filed October 27, 1923. Serial No. 671,172.

To all whom it may concern:

Be it known that I, J AMES C. Woonson, a citizen of the United States, and a resident of East Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Continuous-Conveyor Bake Ovens, of which the following is a specification.

My invention relates to ovens and particularly to ovens of the ventilated type.

One object of my invention is to provide a relatively simple means for regulating the amount of ventilation provided in ovens of the continuous conveyer type.

Another object of my invention is to pro vide a relatively simple means for effecting an air seal at the open end of a continuous conveyer-type oven to prevent the air from escaping outwardly therethrough.

In practicing my invention, I provide a plurality of walls of heat-insulating material enclosing a baking chamber and a return chamber, and having a continuous conveyer traversing both chambers. One of said walls is provided with an opening to permit of placing material on, and of removing it from, said conveyor. A heatlng means, preferably a plurality of electrlc resistor members, is located in said baking chamber.

A conduit is provided to connect the return chamber with the outside air, a part of said conduit being subjected to heat from said baking chamber. A second conduit is connected to the baking chamber itself and also to the first named conduit and suitable dampers are provided for both conduits.

In the single sheet of drawings,

Figure 1 is a view, in vertical longitudinal section, of an oven embodying my invention,

Fig. 2is a View partially in plan and partially in horizontal section, of a part of the oven illustrated in Fig. l and Fig. 3 is a view, in end elevation, of the oven illustrated in Figs. 1 and 2.

An oven structure, designated by the numeral 11, comprises a plurality of outer walls 12, a floor 13 and a roof wall 14, together with side walls that are not particularly illustrated in the drawing; all of said walls being constructed of suitable heatinsulating material.

The oven structure 11 may be of any suitable or desired contour and size and is here I illustrated as beingsubstantially rectangular in section.

A baking chamber 15', of substantially rectangular-contour is located in the intermediate or central portion of the oven structure 11 and is defined by a plurality of end walls 16 of a suitable refractory heatinsulating material and a floor 17, in compending refractory bafile plates 19 may be.

provided to further insulate the return chamber from the baking chamber and to prevent the interchange of air between the two chambers.

A continuous conveyer mechanism for the oven structure 11 comprises any suitable means, such as a plurality of chains 21 located in spaced relation and moving over a plurality of spaced pulleys 22 located in the upper part of the furnace structure 11 and a plurality of spaced pulleys 23 located in the intermediate part of the structure within the lower part of the baking chamber 15.

A plurality of similar pulleys 22 are located in the lower or intermediate portion of the return chamber 18 upon which the chains may move. A plurality of swinging trays 24 are suitably connected to the chains 21, and material to be baked or otherwise heat treated may be placed upon the respective trays 24. An opening 25 is provided at one end of the furnace structure 11 in one or both of the end walls 12 to permit of placing material on or of removing it from the trays.

A plurality of heating elements 26, of any suitable or desired type are located within the baking chamber 15, preferably supported by the floor thereof. As any suitable or desired type of heating means may be employed, the heating means is here illustrated schematically only.

Vith the hereinbefore described construction of an inner baking chamber and of an outer return chamber, there would be a tendency for heated air to flow outwardly through the material-receiving opening 25 and in order to prevent this, I provide a novel 'entilating system comprising a plurality of conduits 27 that are located at the two sides of the oven structure 14 and are operatively connected bysuitable, horizontally-extending portions with the return chamber 18 at its intermediate portion.

\Vhen the oven is in operation,- the tem perature of the air Within the baking chamber isrelatively high, and the temperature of the air Within the return chamber will also be high, but not as high as in the baking chamber, The heated air located in the return chamber will, therefore, flow out of the return chamber and into the substantially vertically extending conduits 27 connected thereto, thereby drawing 'air inwardly through the material receiving opening 25. This provides, therefore, an air seal at the opening and eitectively prevents heated air located in the return chamber 18 from flowing outwardly through the opening, and reducing the efticiency of the oven. The inner walls of the conduits 27 may be made relatively thin and be heated by the air in the baking chamber 15, thereby causing a still greater ventilating eflect.

If it is desired to provide ventilation for the baking chamber itself, as may be necessary, for instance, in drying or baking japanned articles, I provide a plurality of conduits '28, one end of each of which extends through the roof portion 14 into the baking chamber 15. The other end of the conduits 28 may be connected to a horizontally extending conduit portion 29 that has its ends connected to the two vertically extending conduits 27. Dampers 31 may be employed in the respective conduits 27 and 28 to adjust the amount of air that is permitted to flow through them.

It is evident that heated air in the baking chamber 15 will flow outwardly through the conduits 28 and thereby cause an additional amount-of air to enter the opening 25 flowing first downwardly past the lower end of the bafiie'plate 19 and then ast the upper end of the side Walls 16 of the baking chamber.

Wherever it is necessary to provide ventilation in an oven of the continuous conveyer type, such as in japanning ovens, the device embodying my invention provides a relatively simple means for efi'ecting or providing an air seal at the receiving opening or openings, and also results in an increased thermal etficiency of the entire oven.

Various modifications and changes may be made without departing from the spirit and scope of the invention and I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art or are set forth in the appended claims.

I claim as my invention:

1. In an oven, the combination with a plurality of walls enclosing a baking chamber, a return chamber located outside of said baking chamber,- one of said Walls having an opening therein ror access into said return chamber and a hcatin means in said baking chamber, of means tor causing air to flow into said return chamber through said opening.

2. In an oven, the combination with a plurality of walls enclosing a baking chamber, a return chamber located outside of said baking chamber, one of said walls having an opening therein for access into said return chamber, and a heating means in said baking chamber, of means for effecting an air seal at said opening.

3. In an oven, the combination with a plurality of walls enclosing a baking chamber, a return chamber located outside of said baking chamber, one of said Walls having an opening therein for access into said return chamber, and a heating means in said. baking chamber, of means, comprising a conduit connection to said return chamber, for causing air to flow throughsaid opening, into said return chamber and out through said conduit connection.

4. In an oven, the combination with a plurality of Walls enclosing a baking chamber, a return chamber, located outside of said baking chamber, one of said walls having an opening therein for access into said return chamber and a heating means in said baking chamber, or means for causing air to flow into said return chamber through said opening, and means for regulating the amount of air flowing into said opening.

5. In an oven, the combination with a plurality of walls enclosing an inner baking chamber and an outer return chamber, of substantially U-shape, one of said walls having an opening therethrough, and heating means in said baking chamber, of means comprising a conduit operatively connected to said return chamber for permitting air to flow through said opening into said return chamber and out through said conduit and a second conduit operatively connecting said baking chamber and said first conduit to cause air to enter said opening and flow through a portion of said return chamber and of said baking chamber and out through said conduit.

6. In an oven, the combination With a plurality of Walls enclosing a baking chamber and a return chamber, one of said Walls having an opening therethrough, and heating means in said baking chamber, of means 10 energized by the heat generated by said heating means for causing air to flow inwardly through said opening to provide an air seal therefor.

In testimony whereof, I have hereunto subscribed my name this 20th day of October, 1923.

JAMES C. WOODSON.

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