US2789807A - Dipping bath pot - Google Patents

Description

J. A. FALER DIPPING BATH POT April 23, 19:57

2 Sheets-Sheet 1 Filed May 3, 1956 M l .u L h a l 2 M a Q a m IL.

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INVENTOR.

JOHN A. FALER ATTORNEYS April 23, 1957 J. A. FALER 2,789,807

DIPPING BATH POT Filed May 3, 1956 2 Sheets-Sheet 2 40 2o 20 ll I INVENTOR. JOHN A. FALER Qumw g emf? ATTORNEYS United States Patent 6 DIPPING BATH POT John A. Faler, Detroit, Mich., assignor to Kolene Corporation, Detroit, Mich.

Application May 3, 1956, Serial No. 582,448

. 4 Claims. (Cl. 263-11) This invention relates to a dipping bath pot and more particularly to a pot which may be used to provide a molten metal dipping bath such as a molten zinc bath for Esehin galvanizing or such other similar types of molten at S.

It is an object of this invention to provide a pot for molten dipping baths which consists of an inner shell for containing the molten bath and which inner shell is heated by means of heater tubes and a liquid heat transfer medium such as molten salt located in an outer shell surrounding the inner shell.

It is a further object of this invention to cause the heat transfer liquid to circulate throughout the outer shell in such a way as to'prevent the formation of stratified layers of the heat transfer liquid of different temperatures and also to cause the maximum amount of liquid to make full contact with the various heating tubes as the heating liquid is circulated.

Still another object of this invention is to provide an electrical means to electrically remove the scale formed on the wall which is common to both the inner and outer shells which scale would otherwise reduce the efiiciency of heat transfer from the heating liquid to the molten bath.

Still another object of this invention is to provide a means for electrolytically removing the scale formed on the Wall of the inner shell and in addition to assist in the removal of this scale by the use of the heating liquid which is circulated and swirled throughout the outer shell in contact with the wall on which scale is formed.

These and other objects of my invention will become apparent upon reading the following description of which the attached drawings form a part.

In these drawings,

Fig. 1 is a top view of the pot with covers removed and showing the inner and outer shells.

Fig. 2 is a cross-sectional view on line 2-2 of Fig. 2.

Fig. 3 is a phantom view of a portion of the outer shell and shows the partition means used for causing a swirling and wavy motion of the heat transfer liquid circulated through the outer shell.

Fig. 4 is a cross-sectional view taken on line 44 of Fig. l and shows in schematic diagram the electrical means used for electrolytically removing scale.

In galvanizing metallic objects, it is common-to use a molten bath of zinc into which the metallic objects are dipped. There are other processes similar to galvanizing wherein it is desired to provide a metallic molten dip and in some cases a dip of some sort of molten material such as salts or the like other than pure metal such as zinc.

This invention contemplates forming a pot generally designated as which comprises an inner shell 11 surrounded by an outer shell 12. The inner shell is designed to contain the molten dipping bath 13. The outer shell is provided to position a heating means and to provide heat to maintain the molten bath in its proper temperature range and to provide whatever heat is nec- "ice molten salt, as for example, the alkali type shown in Patent No. 2,468,006. Thus, the molten salt or other heat-transferring liquid serves to both transfer heat and also to prevent the tubes from burning themselves out.

It is desirable to circulate the heat-transferring liquid throughout the outer shell in order to maintain an even temperature within the liquid and to some extent this circulation naturally occurs when the liquid is heated. However, I also provide at least one agitator 19 which is a power operated propeller serving to forcibly circulate the liquid throughout the outer shell.

In order to prevent the liquid from stratifying into different layers of varying temperature, that is, in order to completely mix the liquid to maintain an even temperature throughout the heating liquid, I provide a cornpartmentalization system within the outer shell which is formed by partiti0ns21 and 22 spaced apart the various distances and extending transversely in 'thespace between the wall forming the inner shell and the wall forming the outer shell. Within many of these compartments the heating coils or tubes 14 are positioned. The partitions forming the compartment are alternatively arranged so that the partitions 21 begin at the bottom Wall 20 of the outer shell and extend upwardly to a point considerably below the top of the outer shell. On the other hand, the partitions 22 begin at the top of the outer shell and extend downwardly to a'point considerably above the bottom 20 of the outer shell. Thus, with reference to Fig. 3, the heating liquid must take a wavy path in order to travel around the outer shell. This path is generally designated by the arrows marked 24.

The wavy path which must be followed by the heating liquid provides three functions, two of which will be mentioned at this point. Thus, the liquid is constantly swirled and makes a wavy motion which prevents stratification into various heated layers and provides an even mix of the liquid. Secondly, the liquid makes a maximum contact over the elongated or horizontally positioned tubes of the heating element 14. In the absence of such a path of liquid flow, only a small amount of liquid would contact the heating tubes and become heated and thus the remaining liquid would be required to become heated by transfer of heat rather than by direct contact with the heating tubes.

It has been found, particularly where salt is used as a heat transfer liquid, that scale will form on the outer wall of the inner shell 11. This scale has been designated as 29 in Fig. 4. The scale itself is an ozidized formation which after a period of build-up, seriously restricts the free heat transfer through the walls of the'inner shell 11. Therefore, in order to remove this scale, an electrical system is employed which removes the scale electrolytically. This system comprises an anode 30 connected through a D. C. source to a connection point 31 on the'wall of the inner shell. Thus the inner shellwall is maintained negative, the anode is maintained positive. The D. C. current may either be operated continuously to continuously remove the scale, or in the alternative may be turned on and off at any desired time interval to remove scale after a small amount of scale is allowed to build up,

settling out-of the bottom of the outer shell 12 as sludge.-

In order to conveniently remove the sludge that is thus formed I provide a number of pans 40 having handles 41-on the bottoms 20 '0f the outer shell. These pans may be of any formation and serve merely as a convenientmeans to catch the sludge settling out'oftheliquid transfer medium and to remove the sludge by simply pulling the pan out-of the'outershell and emptying these'pansr In addition to'the electrical means of removing the scale,- the swirling movement and wavy movement of the liquid transfer medium serves the additional function of washing over the surface of the wall of the inner shell 11 to remove thoseloose particles of scale which are formed theeron. Thus the movement of the heat-transfer liquid removes part of the scale and the electrolytic means removes the remainder of the scale. Consequently it can be seen that the walls of the inner shell 11 are maintained substantially clean at all times for maximum heat conductivity.

This invention may be further developed within the following attached claims and accordingly it is desired that the foregoing description beread as being merely an illustrative embodiment of my invention and "not in a strictly limiting sense.

Having fully described atleast one operative embodiment of my invention I now claim:

1. A pot for useas a dipping bath comprising ,an, inner shell for containing a molten bath material and surrounded by an outer shell having walls spaced from the walls of theinuershell vand the walls of the inner shell serving .as -c mm9u:. .btw .Ih ut nd h nner e l 4 said outer shell being provided with heating means for transferring heat into the inner shell, the heating means comprising heating tubespositioned in various places with-v in the outer shell and a heat-transferring liquid for transferring the heat from the heating tubes to the common wall of the shells; electrical means for removing the scale formed on the side of the common wall located within the outer shell, said electrical means comprising at least one anode inserted in theouter shell and a D. C. electrical power source electrically connected to the anode and also to the wall of the inner shell wherein the anode is positive and the inner walls are negative 2. A pot as described in claim'l and wherein said D. C. power source is intermittently operated toprovide power at such times as scale builds up to an extent to materially reduce heat conductivity through the wall of the inner shell.

3. A pot as described in claim 1 and wherein said D. C. power source is continuously operated to con- :tinuously maintain-thewall of the innershell negative and the anodepositive to thereby continuously'remove scaleas it"is formed on the wall.

4.. Apot as. defined in-claim 1 and wherein agitator means are provided within the outer shell to continuously and forcefully circulate the heating liquid throughout the outer shell wherein the liquid also functions to washaway;

loose-portions of the scale formed onthe wall.

References Cited in the file of this patent UNITED STATES PATENTS 1,792,614 Bellis Feb. 17, 1931 2,137,693 Lundt Nov. 22, 1933 2,738,294. Spence Max. 13,

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