US1705714A - Cooled rim on cyanide pots - Google Patents

Description

March 19, 1929. c. H. CARPEI qTE-IR ET AL 1,705,714

COOLED RIM ON C YANIDE POTS Filed June 4, 1927 INVENTO R5 (hens/005467400719 A'TTORNEY Patented Mar. 19, 1929.

GRANSTON E. CARPENTER AND ALVIN I).

KEENE, OF MANSFIELD, OHIO, ASSIGNORS TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

Application filed June 4,

creeping will continue until the salt sufficient- I 1y cools to freeze or crystallize. As a result,

. the top of the furnace becomes covered with the salt, and the molten salt also follows the outer surface of the crucible and drops down into the heating chamber, resulting in inju to the electrical resistor.

An object of our invention, therefore, is

to provide, in a salt-bath furnace, means for freezing or solidifying the molten salt at a desired point in the creepage path thereof to prevent injury and contamination of adjacent furnace parts.

In practicing our invention, we provide a salt-bath furnace of the usual type with means for cooling the molten salt adjacent to the rim of the containing crucible, thereby causing the freezing of the salt thereon, and preventing the creeping thereof beyond said rim. Y

In the drawings;

Fig.1 is an elevation, partly in section and partly broken away, of a salt-bath furnace embodying our invention, and

Fig. 2 1s a view, in vertical section, of a portion of a furnace embodying a modification of our device.

Referring more particularly to Fig. 1, a furnace embodying our invention comprises a substantially cylindrical metallic shell 2 provided with a: metallic bottom plate 4. The shell is lined with a plurality of layers of built-up refractory heat-insulating material 6, defining a heating chamber 8. Resting upon the upper face of the refractory wall 6 is an annular plate 10 of heat-resistant material from which is suspended a plurality of sets of electric insulating blocks 12 which support and insulate from each other the convolutions of an electrical resistance element l4, wound in the form of a double helix. The terminals of the resistor 14 are led through the refractory wall 6 and shell 2 COODED RIM ON GYANIDE POTS.

1927. Serial 110.1%,511,

to a terminal box 15, secured to the shell 2, to facilitate the electrical connection of the resistor to a suitable source of energy. The furnace structure is covered by an annular cast metallic plate 16 secured, at its outer periphery, to the shell 2 and formed at its inner periphery with an upturned head which cooperates with a down-turned bead formed on the outer periphery of an annular plate '18, which is co-axial with plate 16.

The inner periphery of plate 18 is formed with an up-turned bead to co-operate in supporting relation with the out-turned rim 20 of a crucible 22.

The engagement of plate 18 with the rim 20 of the crucible is such as to permit of free radial expansion of the elements, and to perniit the free circulation of air beneath and behind the rim 20. The rim 20 is formed unusually wide to provide a considerable area beyond the contact with the upturned bead of plate 18.

The crucible 22 contains the salt utilized in heat treating (not shown), which, in the present instance is a. cyanide.

In the modification shown in Fig. 2, we have adapted the principle of our invention to a salt-bath furnace of a larger size. In this case, the furnace wall is built up of refractory bricks 3O surrounded by a metallic shell 32, having a sinuous electrical resistor 34 supported upon the inner face thereof. A- crucible 36 for containing the molten salt is provided with\a relatively wide and flat flange 38 which issupported upon the top of the refractory wall.

Adjacent to the peripheral edge of flange 38 is a conduit 40 embedded in a mass 42 of fire-clay or other suitable cement. A plate 44 covers the conduit 40 and extends a short distance over the outer portion of the flange 38. A cooling fluid is circulated through conduit 40 and eflects the cooling of the adjacent areasof plates 38 and 44.

The operation of both forms of our device is substantially the same. In Fig. 1, the molten salt will creep up the inner walls of the crucible and over the out-turned rim 20. The temperature differential, however, between the outer portion of rim 20 and the walls of crucible 22 is suflicient to cause the cooling of the molten salt to a point where it will solidify upon the rim. When a considerable amount of the salt has been solidified, it may be chipped or scraped OK. In Fig. 2, the salt will creep out of the crucible and over flange 38 until it reaches the relatively cool outer rim thereof where it will solidify.

Quite obviously, the particular design and construction of the furnace may be varied considerably and still be within the scope of our invention. So far as the operation and function of the invention are concerned, it is practically immaterial what source of heat is employed, but it is particularly advantageous when employing an electrical resistor, as shown, because of the deleterious effect of the creeping salt thereon.

Also, while We have shown and described a salt-bath heat-treating furnace, my inven-- tion is applicable to a vessel containing any liquid which tends to creep beyond the rim thereof and which may be solidified thereupon by an appropriate change in the temperature thereof.

By our invention we have provided an efficient and economical means for preventing contamination and injury of furnace parts incident to the creeping of molten salt out of a containing crucible. v

Modifications may be made in our invention without departing from the s irit and scope thereof, and we desire, there ore, that only such limitations shall be placed thereon as are imposed by the prior art and are set forth in the appended claims.

We claim as our invention:

1. In a heat-treating furnace, the combination with a crucible for-containing a salt which creeps when in a molten state, of means for artificially cooling said crucible adjacent rim to effect the solidification thereon of molten salt creeping out of said crucible.

3. In a heat-treating furnace, the combination with a. crucible adapted to contain a molten salt bath and having a relatively Wide out-turned rim, of means permitting the circulation of air beneath said rim to effect the cooling thereof and the consequent solidification thereon ofv molten salt creeping out of said crucible. I

4. In an electric heat-treating furnace, the combination with a crucible for containing a material which creeps when in a molten state responsive to capillary action of means for preventing said molten material from creeping beyond the rim of said crucible comprising n eans for artificially cooling said rim to cause the crystallization or solidification thereupon of the molten material.

5. The combination with a crucible containing a liquid which tends to creep beyond the rim thereof responsive to capillary action, of means for solidifying said creeping liquid upon the rim of said crucible comprising means for effecting a rim temperature at which said liquid solidifies.

In testimony whereof, we have hereunto subscribed our names this 27 day of May, 1927.

CRANSTON H. CARPENTER. -ALVIN D, KEENE.

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