US3907658A

US3907658A - Anode fitting

Info

Publication number: US3907658A
Application number: US493877A
Authority: US
Inventors: Thomas R B Watson
Original assignee: Corrosion Service Co Ltd
Current assignee: Corrosion Service Co Ltd
Priority date: 1974-08-02
Filing date: 1974-08-02
Publication date: 1975-09-23
Anticipated expiration: 1992-09-23

Abstract

This invention provides an anode fitting for a water tank, which includes a hollow, tubular connector member connected to the wall of the water tank, and an electrode extending downwardly from the connector member. The point of contact between the connector member and the electrode is covered with a fluid-tight protective layer. The hollow interior of the connector member constitutes a fluid passageway which terminates at an opening on one side of the anode fitting, there being a sloping, cam-like surface adjacent the opening, such that accretions and deposits blocking the passageway can be expelled through the side opening by virtue of the cam-like surface.

Description

[ Sept. 23, 1975 ABSTRACT 13 Claims, 8 Drawing Figures Primary E.taminerT. Tung Attorney, Agent. or FirmSim & McBurney This invention provides an anode fitting for a water tank, which includes a hollow, tubular connector member connected to the wall of the water tank. and an electrode extending downwardly from the connector member. The point of contact between the conneetor member and the electrode is covered with a fluid-tight protective layer. The hollow interior of the connector member constitutes a fluid passageway which terminates at an opening on one side of the anode fitting, there being a sloping, cam-like surface adjacent the opening, such that aecretions and deposits blocking the passageway can be expelled through the side opening by virtue of the cam-like surface.

United States Patent [191 Watson ANODE FITTING 22 Filed:

21 Appl. No; 493,877

[56] References Cited UNITED STATES PATENTS 2,401,546 6/1946 2,486,936 11/1949 Fergus 2,652,358 9/1953 McFerran 3,542,663 11/1970 US Patent Sept. 23,1975 She et 2 of 2 3,907,658

m Qu

mm VD V GE mm mm ANODE FITTING This invention relates to a combination anode fitting for use in-the cathodic protection from corrosion of the internal surfaces of hot water storage tanks, automatic water heaters, pressure tanks, and the like.

BACKGROUND OF THE INVENTION In the past. domestic water heater tanks have had a limited life because of the action of corrosion on the internal surfaces of the metal tank. Corrosion is an electrolytic reaction and it depends upon the transfer of small electric charges from some areas on the tank surface to other areas, and back again through the water. The areas from which electrolytic current passes into the water are termed anodes, and these areas corrode. The other areas nearby which are equally necessary to the reaction are places where current flows from the water into the metal, and these surfaces are called cathodes and do not corrode. A transfer of electrons takes place between anode and cathode through the metallic circuit.

While some corrosion will take place in pure water, the reaction is greatly accelerated by the presence of dissolved salts in the water or by heating water to an elevated temperature.

Corrosion may be controlled by alloying iron with other elements such as nickel and chromium, or by covering the surface subject to corrosion with aninert protective coating, either organic or inorganic, or by cathodic protection. This latter mechanism is very effective and well known in the art. It works by impressing an electrolytic current upon the surface of the metal in such a direction as to make the tank as a whole more cathodic and to cancel the natural currents which cause corrosion. Such a protective current may be gen erated by connecting to the steel tank an electrode or anode made of a more active metal such as magnesium, zinc or aluminum. The anode must be in electronic (metallic) contact with the tank and immersed in the water. A continuous galvanic'current flows which re sults in the corrosion of the auxiliary anode and in the protection of the tank. I

Because of the ravages of corrosion, most domestic water heaters in recent years have included a steel tank lined with a proteetivefused frit or glass coating which is bonded to the surface and which prevents contact between the steel and the water. Such coatings, however, are almost always imperfect and small pinholes are present which if unprotected would soon develop into deep pits and eventually perforate the tank. It is to combat this mechanism that such heaters are usually equipped with magnesium anodes or auxiliary electrodes which send a protective current to the exposed metal areas and prevent corrosioni Such a magnesium anode is usually mechanically affixed to the tank either by being screwed into a separate opening in the head or top of the tank used only for the anode, or introduced through a similar threaded opening which serves both as the anode entry and the hot water outlet. In cases where the anode has its own threaded opening or flange, an additional flange is provided into which is screwed a straight nipple which serves as the hot water outlet.

Combination fittings (including an anode mounting and a hot water outlet nipple) which are used in the prior art have generally been of configurations that give rise to problems related to the cleaning of the water passages of accumulated calcareous deposit. In the case of single hot water outlet nipples not associated with anodes, the hot water standing in the nipple at times when no water is being drawn deposits a scale consisting largely of calcium carbonate on the interior surfaceof the nipple, and in waters of high mineral contentthisdeposit sometimes forms a hard plug of scale which limits or completely prevents water flow through the nipple. Where combination fittings are not used. it is simple to disconnect the hot water outlet and force a steel rod-or reaming tool into the end of the nipple and push out the plug of deposit which will fall to the bottom of the tank. Where combination fittings are used, however, the inlet holes to the nipple are usually diametrically opposed and at right angles to the axis of the nipple. Thus, the plug to be expelled would have to make a right-angle turn. This is, of course, impossible, and it is evident that such a plug of deposit could not be cleaned on this type of .device.

Accordingly, one aspect of this invention is to pro-- vide a combination anode mounting and outlet nipple in which there is provided an escape path for accumulated calcareous deposits so that the outlet nipple may be readily cleaned if necessary.

GENERAL DESCRIPTION OF THE INVENTION In view of the above object, this invention provides an anode fitting for a water tank comrising: a tubular connector member adaptec to be secured to a wall of the water tank in electrical contact therewith, a fluid passageway in said connector member, an electrode, means effecting electrical contact between one end of said connector member and said electrode, and fluidtight protective material lining the interior of said connector member, enclosing said means effecting electrical contact, and defining an opening for said fluid passageway, said opening being adjacent said means and including a cam-like deflecting surface which is oriented obliquely to the axis of the connector member such that a cleaning implement inserted into the fluid passageway at the other end of the connector member can clear a plug of deposit through said opening.

GENERAL DESCRIPTION OF THE DRAWINGS Two embodiments of this invention are illustrated in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which: I

FIG. 1 is a partly broken away perspective view of the first embodiment of an anode fitting constructed in accordance with this invention;

FIG. 2 is an axial sectional view of the anode fitting of FIG. 1 taken on the line 2-2;

FIG. 3 is a transverse sectional view of the anode fitting of FIG. 1 taken at the line 33 of FIG. 2;

FIG. 4 is a perspective partial view of an electrode for use in the second embodiment of this invention;

FIG. 5 is a view of the electrode of FIG. 4 showing bending and flattening of the center core;

FIG. 6 is a view showing the relative arrangement of the electrode and a connector member;

FIG. 7 is a view showing the final condition of the anode fitting according to the second embodiment of this invention; and I FIG. 8 is an axial sectional view of the anode fitting of FIG. 7.

DETAILED DESCRIPTION OF THE DRAWINGS Attention is first directed to FIG. 1, in which a wall of a water heater tank has been shown partly broken away. In the wall 10 is a circular aperture 12 in which a flange assembly 14 has been secured. The flange assembly' 14 includes a boss 16 upstanding from an angular flange 17. The boss 16 has internal threads throughout its length. The flange 17 is welded to the wall 10. Threaded into the interior of the boss 16 is a tubular connector member shown generally at 20. The connector member includes an externally threaded hollow nipple 22 and an integral swaged hollow extension 24. The swaged extension 24 can be seen in section in FlGS. 2 and 3, but is covered inFIG. 1 with a fluid-tight protective layer 26 which is provided on the exterior of the swaged extension 24.

The anode fitting of this invention further includes an electrode 28 which is preferably made of magnesium alloy. In the embodiment shown in FIGS. 1 3, the

electrode 28 is cylindrical and has an axial steel core rod 30. Commonly, anodic stock material such as that utilized in the performance of this invention is manufactured by being extruded through a circular die about a central steel rod, and thus it is possible to ensure that the electrical connection between the steel rodand the anodic material is extremely secure. In the embodiment of this invention illustrated in FIGS. 1 3, a section of the anodic material which includes a central steel rod is formed to the outline shown in FIG. 2, in which the rod 30 extends upwardly axially beyond the surrounding anodic material 32. At the upper end of the electrode 28, the anodic material 32 has two step-wise reductions of diameter as shown at 33 and 34, although these are not considered essential. The protruding portion 36 of the steel rod 30 is received tightly within a cylindrical end portion 38 of the swaged hollow extension 24, and is preferably welded thereto.

It will be seen particularly in FIG. 2 that the fluidtight protective layer 26 has its outer surface 40 coextensive with the outer surface of the electrode 28. The layer 26 thus surrounds both of the

reductions

33 and 34 of the electrode 28, and effectively encloses the junction 42 between theconnector member 29 and the electrode 28.

It will'be seen in the figures that the swaged extension 24 has a lateral or side opening 44, and that the tubular connector member 20 has a fluid passageway 45 which, in effect, terminates in the opening 44. It will further be noted that the protective layer 26 spans the opening 44, and protects all portions of the swaged hollow extension 24.

-The anode fitting of this invention also has a further fluid-tight protective layer 46 on the interior of the fluid passageway 45 and extending along the swaged extension 24 adjacent the opening 44. Furthermore,

the further protective layer 46 defines adjacent the opening 44 a cam-like, sloping, deflecting, bottom surface 48 which is angled obtusely to the axis of the connector member 20, such that a cleaning or reaming implement inserted into the upper end of the fluid passageway 45 of the connector member 20 can deflect a plug of scale through the opening 44 by virtue of the cam-like deflecting surface 48.

It will further be noted that the

layers

26 and 46 are in fact integral with one another, and that the edges of the opening 44 are alsoprotected by the material of these layers.

The maximum outside diameter of the electrode 28 and the outer surface 40 of the protective layer 26 may i be smaller than the least inside diameter of the threaded boss 16 to permit entry of the anodic device into the tank, and it will be noted in FIG. 2 that the exterior threads 50 of the hollow nipple 22 are located radially beyond a hypothetical extension of the outer sur-' face 40. v

Although a number of materials may be employed for the

layers

26 and 46, it has been found satisfactory to utilize injection-molded thermoplastics such as polypropylene, polystyrene, polyethylene, and the like.

Attention is now directed to FIGS. 4 through 8, which-illustrate the second embodiment of this invention.

In FIG. 4, an electrode 52 is seen to consist of a central steel core 54, and a surrounding layer 56 of a metal such as magnesium, the layer 56 having a cylindrical outer surface 57. It will be noted that a portion 58 of the steel core 54 extends an appreciable distance outwardly from the end of the layer 56 of metal, the distance of the extension being several times the diameter of the layer 56. It will also be noted that the layer 56 has, adjacent the end shown, a reduced diameter 60 over a short distance from its end face 62.

For the proper working of the anode fitting of the second embodiment of this invention, it is essential that there be electrical contact between the electrode and a tubular connector member adapted to be threaded into a suitable receptacle on the wall of the water heater. While it is clear that contact could be made between the portion 58 of the steel core 54 and a tubular connector member without further altering the projecting portion 58, it will be seen from what follows that it is of advantage to reduce to a minimum the occlusion or blockage of the central fluid passageway of the .con nector member by the portion 58 of the steel core 54. For this reason, the preferred form of the second embodiment of this invention involves the flattening and step-wise bending of the portion 58 of the steel core 54 so that it will take up the configuration shown in FIG. 5. The flattened part of the portion 58 has a very slight curvature whentaken normal to the axis of the electrode, this curvature being the same as the curvature of the inside cylindrical wall of the prospective tubular connector member.

FIG. 6 shows a tubular connector member 64 in the shape of an exteriorly threaded nipple, the latter being partially broken away to show the juxtaposition of the remote end of the portion 58 against the internal cylindrical surface of the tubular connector member 64. In this configuration the two parts are welded, brazed or otherwise attached together to form a secure electrical connection.

Following this connection as illustrated in FIG. 6, a protective material is applied in fluid-tight relationship in such a way that it lines the interior of the tubular connector member 64 with a layer 66, that it encloses the junction between the tubular connector member 64 and the end of the portion 58, and that it defines an opening 68 which is adjacent the flattened portion 58 of the steel core 54. The opening 68 communicates with the central fluid passageway defined within the tubular connector member 64. As in the first embodiment, the fluid-tight protective material defines and constitutes a cam-like deflecting surface 72 which is oriented obliquely to the axis of the tubular connector member, such that a cleaning implement inserted into the fluid passageway 70. at the other end of the tubular connector member 64 can clear a plug of deposit through the opening 68.

Also as in the first embodiment, the fluid-tight protective material extends along and in close, fluid-tight engagement with the electrode 52 for the distance of the reduced diameter 60.

It is particularly clear in FIG. 8 that the flattened and bent portion 58 of the steel core 54 of the electrode 52 is wholly enclosed by and protected by the protective material 74 in the region of the opening 68.

It will further be understood that the completed anode fitting of the second embodiment of this invention would be attached to a water tank or the like in the same manner as is shown in FIG. 1 for the first embodiment of this invention.

While particular embodiment confirgurations have been shown in the drawings and described in the foregoing disclosure, it will be appreciated that the invention is not necessarily limited to the configurational ele ments disclosed. For example, it will be clear that the electrical connection between the electrode 52 in the second embodiment and the tubular connector member 64 need not necessarily be by way of a projecting portion 58 of the central steel core 54. For example, the connection could be by way of a simple electric wire soldered, brazed or otherwise electrically attached to both members. What is important is that the means effecting the electrical interconnection between the electrode and the tubular connector member be shielded and protected by the protective material, and that the protective material define a cam-like deflect ing surface oriented obliquely to the axis of the tubular connector member.

What I claim is:

1. An anode fitting for a water tank, comprising:

a straight tubular connector member having an upper end and a lower end, and adapted to be secured to a wall of the water tank in electrical contact therewith,

a fluid passageway in said connector member having a straight upper end capable of receiving a stiff rodlike cleaning implement,

an electrode,

means effecting electrical contact between the lower end of said connector member and said electrode, and fluid-tight protective material lining the interior of said connector member, enclosing said means effecting electrical contact, and defining an opening at the lower end of said fluid passageway, said opening being adjacent said means and including a sloping, deflecting bottom surface which is oriented obliquely to the axis of the connector member such that a cleaning implement inserted into said upper end of the fluid passageway can clear a plug of deposit through said opening.

2. The invention claimed in claim 1, in which said means includes a hollow extension on said lower end of said tubular member, the end of the extension remote from the tubular member being connected to said electrode so as to provide for said electrical contact.

3. The invention claimed in claim 2, in which said hollow extension is integral with said connector member and has a side aperture aligned with said opening, whereby said fluid passageway communicates through said aperture with said opening, all portions of said hollow extension being protected bysaid protective material.

4. The invention claimed in claim 3, in which said protective material also lines a portion of the exterior of the electrode adjacent said electrical contact.

5. The invention claimed in claim 1, in which said connector member includes an externally threaded hollow nipple of which the lower end is adapted to be operatively secured to the wall of the water tank in communication with an aperture in said wall.

6. The invention claimed in claim 1, in which said protective material is constituted by a thermoplastic chosen from the group: polypropylene, polystyrene, polyethylene.

7. The invention claimed in claim 3, in which said electrode has a steel core projecting from one end, the steel core being welded to the said extension.

8. The invention claimed in claim 1, in which the electrode is of a metal which is electrochemically more active than steel.

9. The invention claimed in claim 1, in which said electrode has a core projecting from one end, and in which said means includes a connection between the projecting core and the connector member, said connection providing said electrical contact.

10. The invention claimed in claim 9, in which the core is steel, and in which the projecting portion thereof has a part-cylindrical configuration and is aligned with the interior wall of said tubular connector member.

11. The invention claimed in claim 9, in which said protective material also lines a portion of the exterior of the electrode adjacent said projecting portion of the core.

12. The invention claimed in claim 9, in which said opening defined by said protective material is located adjacent the projecting portion of the core.

13. The invention claimed in claim 9, in which the connector member is adapted to be operatively secured to the wall of the water tank in communication with an aperture in said wall; in which said protective material is constituted by a thermoplastic chosen from the group: polypropylene, polystyrene, polyethylene; and in which the electrode is of a metal which is electro chemically more active than steel.

Claims

1. AN ANODE FITTING FOR A WATER TANK, COMPRISING: A STRAIHT TUBULAR CONNECTOR MEMBER HAVING AN UPPER END AND A LOWER END, AND ADAPTED TO BE SECURED TO A WALL OF THE WATER TANK IN ELECTRICAL CONTACT THEREWITH, A FLUID PASSAGEWAY IN SAID CONNECTOR MEMBER HAVING A STRAIGHT UPPER END CAPABLE OF RECEIVING A STIFF ROD-LIKE CLEANING IMPLEMENT, AN ELECTRODE, MEANS EFFECTING ELECTRICAL CONTACT BETWEEN THE LOWER END OF SAID CONNECTOR MEMBER AND SAID ELECTRODE, AND FLUID-TIGHT PROTECTIVE MATERIAL LINING THE INTERIOR OF SAID CONNECTOR MEMBER, ENCLOSING SAID MEANS EFFECTING ELECTRICAL CONTACT, AND DEFINING AN OPENING AT THE LOWER END OF SAID FLUID PASSAGEWAY, SAID OPENING BEING ADJACENT SAID MEANS AND INCLUDING A SLOPING, DEFLECTING BOTTOM SURFACE WHICH IS ORIENTED OBLIQUELY TO THE AXIS OF THE CONNECTOR

3. The invention claimed in claim 2, in which said hollow extension is integral with said connector member and has a side aperture aligned with said opening, whereby said fluid passageway communicates through said aperture with said opening, all portions of said hollow extension being protected by said protective material.

13. The invention claimed in claim 9, in which the connector member is adapted to be operatively secured to the wall of the water tank in communication with an aperture in said wall; in which said protective material is constituted by a thermoplastic chosen from the group: polypropylene, polystyrene, polyethylene; and in wHich the electrode is of a metal which is electrochemically more active than steel.