US3142481A

US3142481A - Shaft furnace

Info

Publication number: US3142481A
Application number: US206335A
Authority: US
Inventors: Frederic O Hess
Original assignee: Selas Corp of America
Current assignee: Selas Corp of America
Priority date: 1962-06-29
Filing date: 1962-06-29
Publication date: 1964-07-28
Anticipated expiration: 1981-07-28

Description

F. O. HESS SHAFT FURNACE July 28; 1964 2 Sheets-Sheet 1 Filed June 29, 1962 INVENTOR FREDERIC o. HESS ,Zda i/ ATTORNEY.

F. O. HESS SHAFT FURNACE July 28, 1964 2 Sheets-Sheet 2 Filed June 29, 1962 ATTORNEY.

United States Patent 3,142,481 SHAFT FURNACE Frederic 0. Hess, Sltytop, Pa., assignor to Selas Corporation of America, Dresher, Pa, a corporation of Pennsylvania Fiied June 29, 1962, Ser. No. 206,335 Claims. (Cl. 263-36) The present invention relates to tower furnaces used for the bloating of clay particles and the like, and more particularly to a preheating and feeding means for particles supplied to the furnace.

In the operation of furnaces of the type with which this invention is concerned, clay particles of substantially the same size and shape are dropped through the center of the furnace to be heated to fusion temperature as they fall. The heating process is dependent upon time and temperature. Therefore, the higher the particles can be preheated, the shorter the furnace can be, or the higher the temperature of the product that can be fused in a furnace of a given height.

It is an object of the invention to provide a method and apparatus for preheating particles to be dropped through a tower furnace.

It is a further object of the invention to provide a novel combination of tower furnace and preheat apparatus to be used therewith.

Another object of the invention is to provide a means for preheating and supplying particles to a tower furnace.

The invention is used with a tower furnace similar to that disclosed in Blaha application Serial No. 20,692, filed April 7, 1960, now Patent 3,079,135. Mounted near the top of the furnace are a plurality of fluidized bed type supply units in which the particles are preheated and supp-lied in a plurality of streams to fall in an annular pattern through the center of the furnace.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a section taken through the upper portion of a furnace and the feed mechanism on line 11 of FIG. 2, and

FIG. 2 is a plan view of a portion of the apparatus taken on line 22 of FIG. 1.

Referring to the drawings, there is shown at 1 the upper portion of a tower furnace similar to that disclosed in the above mentioned Blaha application. This furnace is provided with a relatively large and open vertically extending furnace chamber 2, with the furnace being constructed in accordance with ordinary furnace practice. The upper portion of the furnace is provided with a top section 3 that is bolted thereto, as shown at 4. This upper portion of the furnace is constricted so that the top of the furnace chamber is reduced in diameter relative to the main body thereof. The furnace is provided with a plurality of horizontal rows of burners 5, the upper row of which is shown, similar to those shown in Blaha application Serial No. 16,711 now Patent 3,101,773, that are supplied with fuel and air through suitable supply pipes 6. These burners are of a so-called lazy flame type which will heat the furnace without creating a substantially turbulent atmosphere which will elfect the path of the falling particles that are to be heated therein.

The top of the furnace is closed by a refractory ring structure 7 that has formed around its lower edge a water jacket 8 supplied with cooling water through a pipe 9.

3,142,481 Patented July 28, 1964 "ice This jacket rests upon the top of conical section 3, and forms a gas tight joint therein by means of a sand seal 11. There is also provided sealing material 10 that may take the form of asbestos packing between the ring 7 and section 3. Ring 7 is provided with a ring of inlet openings 12 and a central exhaust opening. A stack for the exhaust products of combustion from the burners in the furnace rests upon and extends above the central opening in ring 7. This stack is provided with a sand seal 14 between it and the ring.

Material to be treated in the form of discrete particles of substantially the same size and shape of clay or other material is supplied through the openings 12 in ring 7 from a plurality of supply units indicated generally at 15. Each of these units includes a narrow refractory structure that is divided by a substantially horizontally extending perforated screen 16, preferably of refractory, into an upper chamber 17 and a lower chamber 18. The small particles of material which are to be treated are supplied to the outboard end of chamber 17 through a suitable supply device 19, shown herein as being funnel-shaped, to fall upon the screen 16. The material will travel to the right in FIG. 1, across this screen and over a weir 21 to fall through a discharge opening 22 and opening 12 into the furnace. The material is kept in a fluidized condition, and is heated as it is moved along screen 16 by means of products of combustion from a burner 23 that fires into chamber 18. After passing through the screen in a multiplicity of streams, the products of combustion are discharged through a stack 24. The various supply units extend radially from the furnace, and are mounted around the upper part of the same on a frame 25. The angle of the supply unit can be adjusted by a bolt 26 which will tilt the supply unit around a pivot 27.

In the operation of the apparatus, the small particles of clay or other material that are to be fused are dropped through funnel 19 into chamber 16. Hot products of combustion flowing through the screen 16 keep the particles in a state of turbulence or fluidized condition and heats them as they move along the screen to the discharge opening. Weir 21 insures that the bed of particles will be at the desired thickness so that they will be heated to the proper temperature prior to the time that they are discharged into the furnace.

It will be seen from the drawing that there are a plurality of supply units which are shown herein as being six in number. Each of these units discharges the preheated particles downwardly in a vertical direction through one of the openings 12 into the furnace chamber. The.

arrangement of the supply units and the openings 12 is such that the particles are supplied in an annular pattern formed of a plurality of streams through the center of the furnace. Thus, the particles will fall vertically through the furnace and are heated to their fusion temperature and bloated prior to the time they reach the bottom of the furnace where they are collected in any suitable manner. It will be noted that the diameter of the ring of openings 12 is substantially smaller than the diameter of the furnace chamber, so that the particles will fall vertically through the flames and combustion gases in the center of the furnace without touching the walls of the furnace chamber.

In operating the furnace for fusing or bloating particles, it is desirable to preheat the particles to as high a temperature as possible before they are discharged into the furnace. Some types of clay will bloat at 2800 F., for example, and they must reach this temperature as they are falling through the furnace. Withsuch a clay it is desirable to preheat the particles to about 1800" F. Above this temperature the surface of the particles will begin to get tacky, and the particles will stick together areaasl rather than fall separately. The temperature to which the particles are preheated can be varied by varying the volume of material flowing through the preheater, or by varying the fuel supply. The latter is preferable since it results in constant production. To this end the supply pipes 23 and 29 for fuel and air to burners 23 are provided with valves 31 and 32 respectively. Adjustment of these valves will adjust the temperature developed in chamber 18 as well as the volume of gases flowing through screen 16. Thus, enough gas will fiow through screen 16 to keep the particles in a fluid condition, and the temperature of the gases can be regulated to preheat the particles to the desired temperature.

Each of the particles will be of substantially the same size and shape, but regardless of its size, each particle will be heated to substantially the same temperature. Any dust in the particles will be carried through the stack. In addition, the products of combustion leaving the furnace sweep somewhat across the falling columns of particles as they move into the furnace, so that any dust remaining with the particles will be blown out of the furnace stack. This insures that the atmosphere within the furnace chamber will be free of undesirable dust, thereby permitting the maximum amount of heat to be transferred to the particles as they are being heated.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. The combination comprising a tower furnace provided with a vertically extending chamber, means forming a vertically extending ring of openings and a centrally located opening into the upper end of said chamber and substantially concentric therewith, said ring of openings being smaller in diameter than said chamber, a plurality of supply units each having an inlet opening and a discharge opening, means to mount said supply units on said furnace and extending substantially radially therefrom with the discharge opening of each supply unit vertically aligned with and above one of said ring of openings, each supply unit having a substantially horizontal screen therein, material to be treated being deposited through said inlet opening on said screen, and means to force hot gases upwardly through said screen to carry material along said screen to said discharge opening.

2. In combination, a tower furnace having walls forming a vertically extending chamber and a plurality of inlet openings for material to be treated centrally located in the top thereof, burners in said walls firing directly into said chamber, a supply unit for material associated with each of said openings, each of said units including substantially horizontal means to support a bed of material to be treated and means to force hot gases upwardly through said support and the material thereon and to move material along said support to said inlet opening.

3. The method of supplying material in the form of discrete particles to be treated to a tower furnace which comprises supplying the material to a chamber, moving the material through a path in said chamber by a multiplicity of upwardly moving streams of hot gases which serve simultaneously to preheat the material, discharging the particles vertically downward from said path into the central portion of a chamber in the tower furnace to fall freely vertically therein, and treating the particles individually with heat from the wall of the furnace as they are falling.

4. In combination, a tower furnace having a vertically extending chamber and a plurality of inlet openings in the top of said chamber arranged around the center there of, a supply unit for each of said openings, each of said units including an elongated perforated screen forming a path, means to mount said units on said furnace with one end of said path of each unit adjacent to and above an opening, means to supply particles to be treated to the other end of each of said paths, separate means to force hot gases upwardly through each screen and thereby heat particles and move them along said paths, means to direct particles vertically downward from said one end of each path into the opening adjacent thereto to fall freely through the furnace, and means in the walls of said furnace to treat said particles individually with heat from the furnace walls.

5. In combination, a tower furnace having a vertically extending chamber and an inlet opening to the top of said chamber adjacent to the center thereof, burners in said furnace located to fire across said chamber, a supply unit having an entrance and a discharge opening, means to mount said unit on said furnace with said discharge opening of said unit above the inlet opening of said furnace, substantially horizontally extending means in said unit to support particles to be treated between said entrance and discharge opening, and means to force hot gases upwardly through said support and the particles thereon whereby the particles are heated and moved to said discharge opening and into said furnace.

6. In combination, a tower furnace having an unobstructed and vertically extending chamber and having an opening in the top thereof adjacent to the center, burners in said furnace firing directly into and across said chamber, a horizontally extending fluidized bed heater having an inlet at one end and an outlet at the other end, means to mount said heater above and out of said furnace with the outlet thereof above and aligned with the opening in said furnace top whereby material fed to said heater will flow through the same and fall vertically in a stream into said furnace.

7. In combinations, structure forming a tower furnace having an unobstructed, vertically extending furnace chamber having a plurality of burners between the ends thereof firing directly into the chamber, means to introduce into the top of said chamber a plurality of individual vertically falling streams of particles in front of and displaced from said burners, means to move the particles forming each of said streams as a fluidized stream in a substantially horizontal direction from a first location to a location vertically above one of said openings, said last means including a substantially horizontally perforated screen, means at the end of the screen adjacent to said second location to control the flow of particles, and means to force hot gases upwardly through said screen thereby to heat and fluidize said particles, said gases serving to remove dust from said particles prior to the time they move through the opening.

8. In combination, a tower furnace having an unobstructed, vertically extending furnace chamber, a plurality of burners in the wall of said furnace firing into said chamber, said furnace being provided in the upper portion thereof and above said burners with one or more openings through which material may be dropped into said chamber, said openings being spaced toward the center of the chamber from the wall in which said burners are located, and individual means to drop particles to be eated vertically through each of said openings, each of said means including structure forming a narrow, elongated and substantially horizontal chamber, the structure forming the bottom of said last mentioned chamber being a screen, means to supply cold particles to be heated to one end of said screen, means to force hot gases upwardly through said screen thereby to heat and to move said particles along said screen, and means to direct particles from the other end of said screen vertically downward through an opening into said furnace chamber.

9. In combination, structure forming a tower furnace having an unobstructed, vertically extending chamber, a plurality of burners in the portion of said structure forming the wall of said chamber, said burners firing directly into said chamber, the portion of said structure forming the top of said chamber being provided with a plurality of openings above said burners and displaced toward the center of said furnace from the wall where said burners are located, and means to supply a stream of particles to be heated vertically downward through each of said openings in front of said burners, each of said means to supply including means simultaneously to heat and to move the particles in a fluidized stream from an entrance point at one side of to an exit point vertically above one of said openings whereby streams of particles will fall vertically through said openings and fall through said chamber in front of said burners.

10. In combination, structure including walls forming an unobstructed, vertically extending furnace chamber, a plurality of burners in the Wall of said chamber and firing directly into the chamber, the portion of said structure forming the top of said chamber being provided with a plurality of vertically extending openings displaced inwardly toward the center of the furnace from the wall in which the burners are located whereby particles introduced through said openings will fall in front of said burners, means to supply a stream of individual particles through each of said openings including additional structure forming an elongated chamber having a perforated bottom, means to supply particles to one end of said elongated chamber, means to deliver particles from the other end of said elongated chamber vertically downward to one of said openings, and means simultaneously to heat and to move particles along said bottom from said one end to said other end in a fluidized stream.

References Cited in the file of this patent UNITED STATES PATENTS 2,429,372 Savage Oct. 21, 1947 FOREIGN PATENTS 139,217 Austria Oct. 25, 1934 199,554 Austria Sept. 10, 1958 345,028 Germany Dec. 5, 1921 444,535 Germany May 24, 1927 548,976 Germany Apr. 21, 1932 271,581 Switzerland Feb. 1, 1951 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,142,481 July 28, 1964 Frederic O. Hess It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 32, for "Patent 3,079,135" read Patent 3,071,357 same column 1, line 64, for "Serial N0 16,711" read Serial No. 16,771

Signed and sealed this 20th day of July 1965.

(SEAL) Attest:

ERNEST W. SWIDER' EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims

4. IN COMBINATION, A TOWER FURNACE HAVING A VERTICALLY EXTENDING CHAMBER AND A PLURALITY OF INLET OPENINGS IN THE TOP OF SAID CHAMBER ARRANGED AROUND THE CENTER THEREOF, A SUPPLY UNIT FOR EACH OF SAID OPENINGS, EACH OF SAID UNITS INCLUDING AN ELONGATED PERFORATED SCREEN FORMING A PATH, MEANS TO MOUNT SAID UNITS ON SAID FURNACE WITH ONE END OF SAID PATH OF EACH UNIT ADJACENT TO AND ABOVE AN OPENING, MEANS TO SUPPLY PARTICLES TO BE TREATED TO THE OTHER END OF EACH OF SAID PATHS, SEPARATE MEANS TO FORCE HOT GASES UPWARDLY THROUGH EACH SCREEN AND THEREBY HEAT PARTICLES AND MOVE THEM ALONG SAID PATHS, MEANS TO DIRECT PARTICLES VERTICALLY DOWNWARD FROM SAID ONE END OF EACH PATH INTO THE OPENING ADJACENT THERETO TO FALL FREELY THROUGH THE FURNACE, AND MEANS IN THE WALLS OF SAID FURNACE TO TREAT SAID PARTICLES INDIVIDUALLY WITH HEAT FROM THE FURNACE WALLS.