US1202837A

US1202837A - Electric furnace.

Info

Publication number: US1202837A
Application number: US81736914A
Authority: US
Inventors: Ingenuin Hechenbleikner
Original assignee: SOUTHERN ELECTRO CHEMICAL Co
Current assignee: SOUTHERN ELECTRO-CHEMICAL Co; SOUTHERN ELECTRO CHEMICAL Co
Priority date: 1914-02-07
Filing date: 1914-02-07
Publication date: 1916-10-31
Anticipated expiration: 1933-10-31

Description

fire resistant material.

UNITED STATES PATENT OFFICE.-

INGENUIN HECHENBLEIKNER, OF CHARLOTTE, NORTH CAROLINA, ASSIGNOR TO SOUTHERN ELECTED-CHEMICAL COMPANY, OF NEW YORK, N. Y., A CORPORA-- TION OF NEW JERSEY.

ELECTRIO FURNACE.

Specification of Letters Patent.

Patented Oct. 31, 1916.

Application filed February 7, 1914. Serial No. 817,369.

To all whom it may concern:

Be it known that I, INGENUIN HEOHEN- BLEIKNER, subject of the Emperor of Austria-Hungary, and resident of Charlotte, in the county of Mecklenburg and State of North Carolina, have invented certain new and useful Improvements in Electric Furnaces, of which the following is a specification.

This invention relates to electric furnaces and particularly to such furnaces as may be used in the manufacture of phosphorus vapors and phosphoric acid by heating phosphate rock with silicious material and carbon.

The objects of the invention are to utilize the heat of the furnace gases to uniformly preheat-the charge and to avoid overheating of the brick work, electrodes and other parts ence indicate corresponding parts in all the figures.

Referring to the drawings,- A- represents the body portion of the furnace, B the stack, and C the tapered frustoconical portion connecting the body portion with the stack. These parts will be constructed of suitable I have shown a sheet metal casing D having a lining E of, fire brick. j

The body portion of the furnace is provided with a water jacket F surrounding the sides and bottom thereof and conveniently constructed of sheet metal reinforced with suitable angle irons and channels. The refrigerant, preferably water, is introduced through suitable pipes 10 at the bottom and withdrawn through other pipes 11 at the top. The inner portion 20 of the water jacket is connected at the top only with the outer portion 21 whereby it may be free to expand of one jacket embracing the larger end of the other. The inner jacket is held in position by suitable means, such as a strap 18 on the outer jacket. It will be seen that the inner tap jacket 15 may be readily removed and replaced when it becomes worn out or clogged. Both of the

jackets

14 and 15 are embedded in the fire brick lining E.

The electrodes G and H of carbon or graphite extend through the tapered portion C of the furnace and each is surrounded as it passes through the point where it ,enters the furnace wall with a water cooled jacket I which also serves as a packing box. Each of the jackets 5 is embedded in an extension 26 formed in the side of the tapered portion and may be made from a suitable casting provided with a water inlet pipe 27 and outlet pipe 28. The jacket I is further formed around the electrode with able packing 30, preferably asbestos. To

avoid any current leakage, the water jackets do not form a connected ring around the electrodes, but are separated at 30 by a break in the annulus to leave an isolated space between the ends.

The electrodes are adjustable with respect to the jacket I, and are also formed with suitable current connectors, preferably of a water cooled type, the construction of which does not form part of the present invention. The electrodes are also adjusted and fed by any suitable or well known means. It will be observed the jackets I extend only part way through the fire brick lining, whereby they are protected on the inner side from the heat and chemical reaction within the furnace.

The raw material is fed to the stack B through a suitable charging bell d and the volatile products of the reactions in the furnace are withdrawn through an outlet eon- -duit K, which leads laterally from one side of the top of the stack.

It will be observed that the tapered portion of the furnace is a considerable distance above the electrodes and above the reaction zone, whereby the gases liberated by the re action will preheat that portion of the charge which is in the tapered portion and stack of the furnace.

It will be observed that as the heat of the furnace gases is'reduced the area over which they are distributed is also reduced to correspond, whereby a' uniform degree of heating is obtained and the flow of the furnace gases not restricted by the reduction of area. It will also be observed as the electrodes extend through the smooth inclined body portion of the furnace wall no pocket will be formed above the electrodes in which hot gases might collect to overheat either the. electrodes or the wall of the furnace.

llhis tapered shape also reduces the pressure on the carbon as the portion of the electrodes within the furnace is not subject to the entire weight of the charge in the stack. The furnace is particularly adapted for use in a process for the manufacture of phosphoric acid in which the material to be furnaced consists of a mixture of natural phosphate rock, silicious material and carbon, and the furnace gases consist of phosphorus vapor, carbon monoxid and phosphoric acid, which furnace gases assist in preheating the charge in the manner already explained.

It is essential in this process in the manufacturing of phosphorusior phosphoric acid, that the temperature shall be well regulated and the intense heat of the electric are so applied to avoid a local overheating of the charge or of the slag. Overheating of the charge or slag will cause a distillation of not only phosphorus but will also produce a distillation of silicon compounds.

Silicon and silicon compounds are generally the cause of killing the phosphorus, or, in case the phosphorus is afterward oxidized for the manufacture of phosphoric acid, said phosphoric acid forms water insoluble, commercially worthless compounds containing SiO and P 0 To prevent these disadvantages in the process the typical design of the furnace shown is the most important feature. Tests have shown that in the case of this furnace the charge moves regularly and under a steady pressure downward between and around the electrodes. In this way the once melted and reduced slag is removed quickly out of the dangerous arc zone before overheating can take place. Fresh material replacing quickly the melted slag prevents the formation of hollow spaces between the electrodes and charge, and at the same time prevents overheating of material and distillation of silicon and silicon compounds; It makes no difference whether the material be powdered, ranulated or briqueted, if the melting of the material be as described above since no distillation of harmful compounds takes place. The break in the water jacket around the electrode already described is found to be particularly useful for an alternating current.

In the practical operation of the furnace the calcium silicate slag will flow continu ously through the upper tap holes 12, while any heavier material, such as iron may from time to time be taken out through the hole '13. @wing to the high conductivity of the hot melted slag and metallic water jacket, it is necessary that the furnace should be thoroughly insulated from the ground.

Having thus described my invention, what I claim is:

1. An electric furnace having an expansible water jacket formed with disconnected parts inclosing the sides and bottom in a continuous manner.

2. An electric furnace comprising a body portion, a water jacket thereon formed with disconnected parts, an uncooled masonry tapered portion formed with integral masonry extensions on the sides, electrodes extending through the extensions, and water jackets for the electrodes extending partially in the extensions and being supported thereby.

3. An electric furnace comprising a cylindrical bottom portion in which the greater part of the reaction is adapted to take place, formed with separated tap holes, a tapered portion above the cylindrical portion and having a wall tapering uniformly inwardly from the same, electrodes extending through the tapered portions and projecting downwardly into the body portion, and a top cylindrical portion formed with a laterally extending conduit integral therewith.

4:. An electric furnace comprising a body portion, a masonry tapered frusto-conical portion formed with integral extensions on the sides, a stack above the tapered portion and electrodes extending through the extensions on the tapered portion and extending downwardly into the body portion.

6. In an electric furnace, at body portion, ed to extend completely around the same, 15 a water jacket surrounding the sides and 'save for a Single gap which .forms an insubottom thereof and constructed of vsheet lating space between the ends. metal reinforced with angle irons and chan- Signed at 141 Broadway, in the county of 5 nels, the inner portion of the Water jacket New York andState of New York this 4th being connected at the top only with the day of February, A. D. 1914:.

outer portion whereby it may be free. to ex- INGENUIN HEGHENBLEIKNER. pand and contract. Witnesses:

7. In an electric furnace, a, water jacket RUssEL S. SMART,

1 adapted to surround an electrode and adapt- HARRY W. THoMPsoN.