US1371773A - Furnace or oven - Google Patents

Description

H. B. CANNON.

FURNACE 0R OVEN.

APPLICATION FILED MAR.29, 1920.

Patented Mar. '15, 1921 UNIED STATS H B. OA' NNON, OF PORT HURON, MICHIGAN.

FURNACE 0R OVEN.

Specification of Letters Patent.

Patented Mar. 15, 1921.

Application filed March 29, 1920. Serial No. 369,458.

To all whom it may concern:

Be it known that I, HIRAM BJCANNON, acitizen of the United States, residing at Port Huron, in the county of St. Clair and State of Michigan, have invented a certain new and useful Improvement in Furnaces or Ovens, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

This invention relates to ovens, and more particularly to ovens which are employed for the purpose of heating through radiation articles such as japanned and enameled Ware and which articles are liable to injury through contact of the products of combustion therewith. It is the general purpose and object of my invention to provide for such purposes a heating or combustion chamber which is capable of radiating the heat more efliciently than any other type of heating or combustion chamber with which I am familiar; also to construct an oven employing a chamber of this type and which will be extremely efficient in operation.

I secure these objects in and through the embodiment of my invention shown in the drawings forming part hereof, wherein Figure 1 represents a central vertical sectional view through an oven constructed in accordance with my invention; Fig. 2 a horizontal sectional view through said oven; Fig. 3 a transverse sectional view corresponding to the line 3-3 of Fig. 1; and Fig. 4 a detail in perspective of the combustion tube or chamber and the air duct.

Describing the parts by reference characters, 1 denotes the casing of the oven, said casing being made of any suitable resistant material, such as. fire-brick, and lined with insulating material, such as kieselguhr brick indicated at 1 and being preferably rectangular in longitudinal and transverse sec tions and having the upper wall 2 thereof arched.

The oven shown herein is designed for the heating of articles, such as ja-panned or enameled ware, which may be inserted 'into the oven by means of cars on rails 3 extending longitudinally of the furnace and supported in any convenient manner, as by means of transversely extending inverted channel beams 4, the oven being provided with front and rear doors 5 permitting the introduction and removal of such cars.

In the central portion of the space below the rails and beams is a combined combust1on and heat-radiating chamber, indicated generally at 6. This chamber is shown as circular in cross-section, but may be of any desired shape. At its front end, it is provided with a plug or plate 7 having a central opening 8 registering with the delivery end of a fuel injector 9. This injector may be of any commercial type adapted to supply gas, pulverized fuel or oil to the combust1on chamber and to produce a high temperature within the chamber 6. I have indicated for this purpose a burner or injectorknown to-the trade as the Bellevue Oil Burner and adapted to deliver to the chamber 6 an atomized mixture of oil and air, and capable of producing a flame of great heat intensity with low pressure air and oil.

The end of the chamber 6 which is remote from the plug 8 is closed as by means of a plug or plate 10. Adjacent to said plug or plate, the chamber 6 is provided with oppositely extended nipples adapted to receive pipes 12, preferably of sheet metal.

These pipes extend across the rear of the oven chamber and thence forwardly, in close proximity to the side walls of said chamber and beneath the beams 4, to the front of the oven. Each pipe 12 is bent upwardly, near the front of the oven, as indicated at 13 and extends thence to the rear of the oven, where it is again bent upwardly,-

as indicated at 14, thence forwardly, as 111- dicated at 12", etc., providing at each side of the furnace successive courses of pipe extending from front to rear thereof, as indicated at 12, 12", 12, 12, 12, and 12, the

uppermost length 12 extending through the furnace wall, as indicated at 15. The delivery ends of these pipes may be connected to an exhaust device (not shown) For the chamber 6 I employ a material capable of radiating its heat very rapidly tothe surrounding space. I have found that carborundum preferably mixed with a small portion of binding or bonding material (such as fire-clay), and molded'to shape, possesses the quality of radiating heat to a very marked degree. Furthermore this material is practically indestructible by high temperatures, such as produced by the use of any of the commercial injectors for gas, oil, or pulverized fuel. A further advantage arises from the fact that it has a very low coefficient of expansion, whereby it will not crack on rapidly heating and cooling,

and that its tensile and compressive strength is not only high, but is unafiected by great variations in temperature. w

The chamber 6, as will appear more particularly in Fig. 1, is conveniently made of a number of sections 6*, 6", 6, 6, of carborundom, the ends of the sections being butted' together and beveled, to. form in 'eifect a ground-joint connection between adjacent sections. The conduit is supported at its ends and at the joints between its sections on blocks 16, preferably of carborundum and each havinga concave'upper surface conforming to the exterior of the sections. The lower courses of the pipes 12 may be supported by similar blocks 17 The wall of the chamber 6 diminishes substantially uniformly in thickness from the front to the rear end thereof, as will appear more particularly fromFig. 1, wherein the walls of the section 6 and the rear section 6 are shown as tapering or gradually diminishing in thickness from front to rear.= This en-- ables the wall of the combustion and radiating chamber to radiate heat uniformly ward the opening 8. Additional horizontal baflles 18 and 18 may be inserted in said chamber at suitable intervals. These baflies, as well as the plates or plugs 7 and 10, may

1 also be of carborundum. The purpose of the baffles is to shorten the flame produced by the ignition of the mixture from the burner 9 and to secure a proper admixture of the fuel and air, thereby to obtain complete combustion within the chamber 6, as well as to concentrate the greatest heat within the first sections of said chamber.

The roof of the oven is provided with. an outlet 19 controlled by a damper 20. This outlet serves to permit the fumes and volatile products of the coating of the ware to particularly during the initial stage escape, of t e heating operation. V

In order to carry oif these fumes and volatile products in the most efiicient manner, an air duct 21 is provided beneath the chamber 6, the supporting blocks 16 for the said chamber extending across the upper portion,

of said duct. -The front wall of the oven is cut away to permit access of air to said duct,

rm k V T the inlet end of the duct being provided with a door 22. It will be noted from Fig. 4; that a narrow slot 23 is provided between each side of the. chamber 6 and the upper portion of the duct 21. These slots will be so pro-- portioned to the cross-sectional area of the duct that a substantially uniform delivery of air throughout the entire length of the duct and in contact with the chamber will be secured. Above the chamber 6 is a metal plate 24 which is adapted to receive any drip from the liquid coating of the articles thereabove and prevent the same from contacting with the highly heated chamber 6.

In operation, with a temperature of from 2500 to 3000 F within the front portion of the chamber 6 and with a chamber over ten feet long, the chamber has assumed a yellowish-white color throughout its length.

Owing to its great conductivity or permeabilit and capacity for heat radiation, by the time the products of combustion shall have reached the rear end of the said chamber, the temperature will have been reduced to such extent as to enable me to use sheet metal for the extensions 12, the cost of which material is considerably less than that employed for the chamber 6. h

After the articles have been heated to an extent to liberate the volatile ingredients of the coating, the damper 20 will be opened and the door 22 also opened to a slight extent, permitting an upward circulation of air through the oven to carry off such products. After the. evolution of these products has ceased, both the damper and the door may be closed. This permits me to introduce into the oven articles having a coating in a wet condition, without'the necessity for preliminarily air-drying the same.

An oven constructed in the manner described herein utilizes in a most efiicient manner the heat generated by the combustion of the products from high temperature burners and materially reduces the time recipired for the treatment of the articles t erein. The chamber 6 and the extensions thereof are suspended in a bath of air which is circulated in a most eflicient manner in contact with the articles to be heated within the oven.

Having thus described my invention, what I claim is 1. An oven having a space for subjecting articles to heat by radiation, and a combustion chamber in operative relation to such space and out of communication therewith, said. combustion chamber being composed principally of carborundum.

2. An oven having a space for subjecting articles to heat by radiation, and a combustion chamber in operative relation to such space and out of communication therewith said combustion chamber being composed principally of crystallized carborundum.

3. An oven having a space for subjecting articles to heat by radiation, and a combustion chamber arranged to heat such space by radiation and being out of communication with such space, the said combustion chamber comprising a plurality of sections of carborundum, the joints between the said sections being tapered, and supports for'said chamber engaging the joints between the sections thereof.

4. An oven having a space for subjecting articles to heat by radiation, and a combustion chamber arranged to heat such space by radiation and comprising a plurality of sections of carborundum.

5. An oven having a space for subjecting articles to heat by radiation, and a combustion chamber in operative relation to such space but out of communication therewith, said combustion chamber being composed principally of carborundum and having an inlet outside the said space, a bafiie within said chamber adjacent to said inlet, and a 31161 injector arranged to discharge into said et.

6. An oven having a space for subjecting articles to heat by radiation, and a combustion chamber in operative relation to such space, said combustion chamber being composed principally of carborundum and having an inlet outside the said space' a baffle within said-chamber adjacent to sald inlet, and a fuel injector arranged to discharge into said inlet.

7. An oven having a space for the reception of articles to be heated by radiation, a combustion chamber in operative relation to such space but out of communication therewith, said combustion chamber being composed principally of carborundum, means for supplying a combustible mixture to one end of said chamber, and sheet metal pipes connected to the said chamber adjacent to its opposite end and extending to the sides of sai space and being arranged each in a series of horizontal courses at one side of such space and delivering outside such space.

8. An oven having a space for the reception of articles to be heated by radiation, a

combustion chamber in operative relation to such space but out of communication therewith, said combustion chamber being composed principally of carborundum, means or supplying a combustible mixture to one end of said chamber, and lateral extensions connected to the said chamber adjacent to its opposite end and extending to and along opposite sides of said space and delivering outside such space.

9. An oven for the purpose'specified having in the lower central portion thereof a carborundum combustion chamber extending from the front to the rear thereof,'pipes connected to the rear end of the combustion chamber and extending to and along opposite sides of the furnace or oven, the delivery ends of said pipes extending outside said furnace or oven, and a track in said furnace or oven above said combustion chamber.

10. An oven for the purpose specified having in the lower central portion thereof a carborundum combustion chamber extending from the front to the rear thereof, extensions connected to the rear end of the combustion "chamber and extending to and along opposite sides of the furnace or oven, the delivery ends of said extensions being located outside said furnace or oven, and means for supporting articles in said furnace or oven above said combustion chamber.

11. in oven for the purpose specified having in the lower portion thereof a combustion and heat radiating chamber, the said oven having a controllable outlet for the escape of volatile products and a conduit for air -beneath said chamber and arranged to discharge into said oven on opposite sides of said chamber, means for controlling the flow of air through said conduit, and a protecting plate in said oven above said chamber.

12. An oven for the purpose specified having in the lower portion thereof a combustionand heat radiating chamber and an air duct extending beneath said chamber and forming with and on each side of the latter a discharge slot, means for controlling the flow of air through said duct, and a controllable outlet from the upper portion of said oven.

In testimony whereof, I hereunto aflix my 100 signature.

HIRAM. B. CANNON.

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