US2508171A - Electrode construction - Google Patents

Description

May 16, 1950 w. KAUFMAN ELECTRODE CONSTRUCTION Filed Aug. 19, 1948 INVENTOR Laws VV. Kaufman BY ATTORNEY Patented May 16, 1950 ELECTRODE CONSTRUCTION Louis W. Kaufman, Mansfield, Ohio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application August 19, 1948, Serial No. 45,077

2 Claims.

My invention relates to electrode constructions applicable to water storage tanks for preventing corrosion thereof and has for an object to provide improved apparatus of this kind.

A further object of the invention is to provide an electrode of this kind which may be readily applied to a tank installed in a room having low head room,

f A still further object of the invention is to provide an improved electrode of the type set forth which may be readily manufactured.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a vertical, sectional view taken through a domestic hot water storage tank having an electrode applied thereto which is constructed and arranged in accordance with my invention;

Fig. 2 is a longitudinal, sectional View taken through the electrode construction shown in Fig. 1;

I Fig. 3 is a sectional view taken through an anode element during assembly thereof to the supporting core; and

Fig. 4 is a transverse section taken along the line IVIV of Fig. 2.

As is well understood, corrosion of the walls of water tanks is due primarily to electrolysis. Impurities in the metal forming the tank or the use of dissimilar metals produces a multitude of anodic and cathodic regions so that a number of galvanic currents are produced. Corrosion occurs at the anodic areas and, after a period of time, the tank is rendered unfit for use. The employment of an electrode formed of metal anodic with respect to the tank structure has been known for many years for providing a galvanic current which neutralizes the galvanic currents produced by impurities in the metal forming the tank. A rod of magnesium having one end electrically connected to the tank is usually employed for this purpose, as magnesium is anodic with respect to al1.metals usually found in a tank structure. For the protection of domestic hot water tanks, a rod approximately one inch in diameter and of the order of fifty inches in length extends into the water centrally of the tank side walls. During operation, the anodic sacrificial rod is corroded by the galvanic current and requires periodic replacement,

Due to low head room usually prevailing in rooms housing the tank, the replacing of the rod usually involves the disconnection of the tank from the piping in the house so that the tank 2 may be tilted for the insertion of the rod. It ha been proposed to form the rod in short lengths which may be screwed together as they are individually inserted in the tank. However, corrosion at the threaded connections rapidly occurs and the resistance to current flow at these oxidized junctions may reduce the galvanic current produced to a value insufiicient for protection of the tank.

In accordance with the present invention, I propose to use a plurality of blocks of magnesium or other suitable metals which are carried by and longitudinally spaced upon an elongated resilient member formed, for example, of synthetic rubber. A current conducting wire is helically wound on the surface of the core and the blocks or anodes have cylindrical openings therein for receiving the core. The outside diameter of the core and wire helix is slightly greater than the openings in the anodes when the resilient core is free and slightly less than said diameter of the openings when the core is longitudinally stretched. With the core stretched, the anodes may be readily threaded on the core and over the wire helix in proper spaced relation during assembly of the electrode and, when the tension on the core and wire helix is removed, they expand and the helical wire is forced into contact with the surface of the openings in the anodes. Accordingly, all anodes are electrically connected together by the wire. The wire is also electrically connected to the plug which closes the opening in the water tank and which serves to support the electrode in the tank. This construction permits the bending of the electrode structure so that it may be inserted in a tank even though the head room available is short. Since the electrode construction may be assembled at the factory where all electrical connections are properly made, the proper flow of protective current is assured and the difi'lculties set forth heretofore in connection with the assembly of various rod sections during installation are obviated.

Referrin now to the drawing, I have shown my improved electrode construction, generally indicated at It, applied to a conventional domestic hot water storage tank II, the latter including respective conduits I2 and I3 for the admission of cold water and for the discharge of hot water. The top wall of the tank indicated at M is provided with a threaded opening 15 through which the electrode construction It) is inserted in the tank. The means for heating the water has not been shown since it forms no part of the present invention.

The electrode construction In includes a plurality of spaced anodes l6 formed of a material, for example, magnesium which is anodic to the material from which the tank is fabricated. The anodes l6 are each provided with generally cylindrical openings I l for receiving a resilient core l8, the anodes 16 being longitudinally spaced on the core l8 as shown in Fig. 1. A current conducting wire l9 formed of any suitable metal is helically wound on the resilient core 18 and serves to electrically connect all of the anodes 16 together.

The upper end of the core l8 and the helical wire closely fit within an opening 2| formed in a plug 22 which is threaded in the opening I-S of the tank wall 14. The upper end of the helical wire I!) is forced by the resilient core I 8 firmly into engagement with the surface of the opening 2| so that the wire I9 is electrically connected or grounded to the plug 22. In order to prevent displacement of the core l8 from the plug, 22, the latter maybe crimped, as shown at 23, to firmly grip the resilient core I8.

In order to facilitate the manufacture or as sembly of the anodes I and the core l8, the openings ll have a diameter which is slightly less than the over-all diameter of the core I 3 and helical wire I9 when the core I8 is free, but, when the core l8 and wire I!) are stretched longitudinally, the: diameter of the wire helix I9 and the core I8 is reduced to a value slightly less than the diameter of the opening ll. Accordingly, when the core l8 is stretched the anodes l6 may be; readily moved along the core and helix [9 to their proper positions after which the tension is removed from the core. The removal of tension from the core l8 permits expansion of the core l8 and the helical wire l9 so that the latter is firmly forced intocontact with the surfaces of the openings ll. Accordingly, all of the anodes l5 and the plug 22- are electrically connected by the wire l9.

During operation of the electrode l0 when installed in awater tank, protective currents flow from the various anodes l6 through the water to all regions of the tank walls and thence through the plug 22 and the conductor I9 to the anodes l6. As isv well understood, these galvanic protective currents neutralize the currents flowing from thenumerous anodic areas of the tank walls and prevent. corrosion at these areas. The anodes l6 are spaced apart to uniformly distribute the protective current to all regions of the tank walls. Preferably, the. uppermost anode It is so spaced below the plug 2-2 that the protective current flowing from this anode IE to the top wall I l approximates the current flowing to all of the regions of the: tank. walls. Accordingly, rapid corrosion of the upper anode I6 is avoided.

The spacingof the anodes E6 on the resilient core !8. permits bending of the electrode construction Itv when. applied to a tank having low head room. The electrode construction I'El may be sharply bent as it is threaded through the opening 15 to. its operating position.

From the foregoing description, it will be noted that. thecore I8 is slightly compressed in the anodes l6= and prevents the admission of water to the opening I]. in the anodes. Accordingly, corrosion. of the anode surfaces defining this opening is prevented. The flow of current from the anodes is from the surfaces in contact with the water- In this connection, it will also be noted that corrosion of the wire l9 does not occur 0 Number since the material forming this wire is cathodic with respect to the anode and, therefore, a protective current will always flow from the anodes to the portions of the wire H! which are exposed to the water.

From the foregoing description, it will be apparent that I have provided an improved electrode for cathodically protecting a water storage tank against corrosion, which electrode, being flexible, may be bent to facilitate the installation thereof in a tank where the available head room is limited. Since the electrode may be completely fabricated as a unit at the factory, it may be readily and economically installed without adjustments or the completion of electrical connections at the time of installation. Furthermore, the completion of the electrode at the factory' as a unit assures uniform potential between the various electrodes l6 and the tank and, therefore, uniform distribution of the protective current to-all surfaces of the tank walls.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modfiications without departing from the spirit thereof.

What I claim is:

1. In an electrode construction of the character described, the combination of a supporting plug, an elongated resilient core carried by the plug, a wire helically wound on the exterior of the core and a plurality of anodic members spaced longitudinally on the core, said members having generally cylindrical openings extending therethrough for receiving the resilient core and the wire wound thereon, said resilient core and helical wire having a free diameter slightly greater than the diameter of said openings and, when longitudinally stretched, a diameter slightly less than the diameter of the openings, the construction andarrangement being such that the anodic members may be moved longitudinally on the core when the latter is stretched and are gripped by the core when free, the helical wire being forced outwardly by the core into engagement with the surfaces of the openings and electrically connecting the anodic members together.

2. In an electrode construction for a water storage tank having an aperture in a wallthereof, the combination of a plug adapted for closing the aperture in the tank, an elongated resilient core fixed to said plug and adapted to extend within the tank, an electrical current conducting wire helically wound on the outer surface of said core and electrically connected to said plug and a. plurality of anodes spaced apart longitudinally of said core, said anodes having respective openings therein for receiving the core and the helical wire wound thereon and said core resiliently urging said wire into engagement with the surfaces of said openings for electrically connecting the wire and the various anodes.

LOUIS W. KAUFMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Delius et a1 Apr. 8, 1924 Butler Oct. 12, 1948

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