US1566224A - Furnace - Google Patents

Description

Dec. 15 ,1925

lrlwventor: Wesley F'. Massey.

Filed J His Attorney.

Patented Dee 15,- 1925.

UNITED STATES' 1,566,224 PATENT OFFICE.

WESLEY IF. MASSEY, lF BAIiLSTON SPA, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

FURNACE.

Application led .Tune 1,2, 1324. Serial No. 719,688.

To all whom tymay concern.'

Be it known vthat I, WESLEY F. MAssEY, a citizen of the United States, residing at Ballston Spa, in the county of Saratoga, State of New York, have invented certain new and useful Improvements in Furnaces,

vof which the following is a specification.

' desirable that the furnace should be sealed in such manner as not only to assure the maintenance of the vacuum but also to allow the furnace to be easily and quickly opened and closed. One method of sealing the furnace of this type is to secure the cover in place by means of suitable bolts o r lag screws. With this method, however, 1t is a tedious operation to open and close the furnace.

In carrying out my invention I seal the furnace with a fusible material, which may be solder, and provide means for melting the sealing material when the furnace 1s to be opened or closed.

cover 11.

For a more complete understanding of my invention reference should be made to the accompanying drawing inwhich Fig. 1 isV an elevation view in section of an electric furnace embodying my invention, while Fig. 2 is a section view along the line 2-2 of F ig. l looking in the direction of the arrows.

Referring to the drawing, I have shown my invention in one form as applied to an electrically heated vacuum furnace although my invention has obvious application to furnaces in general regardless of the method of heating. The furnace comprises a cylindrical casing or tank 10 provided with a This casing is made yof a nonporous material of sufficient strength to permit its being evacuated. It is preferably made of a metal, such as steel. Inside the casing is an electric heating resistor 12, shown as a wire wound in the form of a helix on a support 13 made of insulating material. Between the heating resistor and the tank 10 is a cylindrical member V1l made l of suitable heat insulating material by means of which direct radiation of heat from the resistor to the tank is prevented. The members 13 and 14 may be made of alumdum. The ends or terminals 15 and v16 of the heating resistor are brought out through the sideof the tank 10 through suitable insulating and packing bushings 17 and 18, whereby the terminals are lelectrically insulated from the tank and leakage around the terminals is prevented.

My present invention relates more particularly to the provision of a seal between the cover 11 and the tank. For this purpose an annular trough-like receptacle 20 is secured on the outside of the tank at the upper end thereof,` forexample by brazing or welding so as to provideia tight joint between the receptacle and the tank. The cover 1,1 is provided with a peripheral `flange 2l which extends downward when the cover is in place into the receptacle 20. In the receptacle is a mass of suitable fusible sealing material 22 which may be a. metal, such as a solder.

- Associated withthe receptacle is an electric heating unit 23 by means of which the sealing material 22 may be melted to permit the cover to be put in place or removed in closing and opening the furnace. ing unit may be of any suitable form and is shown as comprising a resistance conductor embedded in compacted insulating material in a metallic sheath, for example, asidescribed and claimed'in U. S. Patent No. 1367341 to Charles C.' Abbott. The heating unit is bent in the shape of a ring and is placed in the bottom of the receptacle 20. Terminals 24 and 25 of the heating unit are brought out through the side' of the receptacle for connection to a suitable electrical supply s ource.

As thus constructed and arranged, it will be observed that when the cover is in place the flange 21 is embedded in the fusible sealing material 22 which thus forms a tight joint between the cover and the tank. In closing the furnace the fusible material is rst melted by means of the heating unit 23, after which the cover is simply put in place and the sealing material allowed to cool. IVhere the sealing material is a solder, a soldered joint is thus formed between the cover and tank. This provides a very etli- This heatcient leak-proof joint and one which can be easily and quickly made. In opening the furnace it is necessary only to first melt the sealing material by means of the heating unit whereby the cover is released and can be removed. It will be understood that the articles to be heated are placed inside the inner insulating cylinder 13. The furnace chamber may be evacuated through the pipeQ provided for that purpose which leads to a suitable evacuating pump. (Not shown).

The outer envelope of the furnace cou- .sistingof the tank with its cover 11 is preferably cooled by submerging it in waterin a tanlLQT. The terminals and 16 are brought out through thc wall of the tank 27 through suitable packing and insulating bushings 28 and 29. Tater may be introduced into the tank through a water inlet pipe 30 at the bottom, an overflow pipe 31 being provided at the top. lVhen it is dcsred to open the furnace afterthe complelion of the heating the water is drained out of the tank Q7 below the upper level of the tank 10 and preferably below the receptacle 2O so that the receptacle will not be cooled by the Water while the sealing materlal is being heated.

While I have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing'from the by Letters Patent of the United States is l 1. The combination with an electric furnace, of a fusible material for sealing said furnace, a receptacle for said fusible material, and an electric heating unit in said receptacle whereby the `sealing material may be melted to open said furnace.

2. The combination with an electric furnace, of a cover for said furnace, a mass of fusible material forming a tight joint between said furnace and cover, a receptacle for said fusible material, and an electric heating unit in said receptacle whereby the fusible material mayy be melted to release said cover.

The combination with an electric-furnace provided with a cover, of a receptacle around the mouth of said furnace into which the cover extends, a fusible metal in-said receptacle. sealing,r said furnace', and an electric heating unit in said receptacle, whereby the metal may be fused to permit the -removal of said cover.

4. The combination with an electric furnace provided with a metallic casing, a cover for said casing, a mass of solder forming a sealed ]o|nt between sald casing and cover,

a receptacle for said solder, and a.- sheathed

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