Sacrificial Collar

Abstract

A sacrificial collar that is placed on a structural component to protect against stray current or galvanic corrosion. The collar includes an upper section having a half-circle cavity, and a corresponding lower section having a half-circle cavity. When the two sections are mated, the two cavities together create a single circular opening. The two sections are placed on a structural component, with the component secured between the sections, in the opening. Attachment means, preferably in the form of a bolt and nut combination are utilized to attach the two sections together and secure the collar on the structural component. Once secured, the sacrificial collar is subjected to stray current or galvanic corrosion, thereby causing the collar to deteriorate, instead of the structural component being subjected to stray current or galvanic corrosion which would cause the component to deteriorate and would destroy the component.

Description

TECHNICAL FIELD

The invention generally pertains to structure components, and more particularly to a sacrificial collar that is placed on an underwater structural component of a sea vessel to protect against stray current or galvanic corrosion.

BACKGROUND ART

Two of the most significant problems that affect submerged components of a sea/water vessel are stray current corrosion and galvanic corrosion. Stray current corrosion is a serious destructive occurrence and results from a metal with an electrical current flowing into it submerged in water that is grounded, such as a lake, river or ocean. The current can leave the metal and flow through the water to ground. This will cause rapid deterioration of the metal at the point where the current leaves. Stray direct current is particularly destructive.

Galvanic corrosion (also called “dissimilar metal corrosion”) refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte. The corrosion occurs when two (or more) dissimilar metals are brought into electrical contact usually under water. When a galvanic couple forms, one of the metals in the couple becomes the anode and corrodes faster than it would by itself, while the other becomes the cathode and corrodes slower than it would alone. Either (or both) metal in the couple may or may not corrode by itself. When contact with a dissimilar metal is made, however, the self-corrosion rates will change. Corrosion of the anode will accelerate and corrosion of the cathode will decelerate or even stop.

The major cause for corrosion is a potential difference between the different materials. The bimetallic driving force was discovered in the late part of the eighteenth century by Luigi Galvani in a series of experiments with the exposed muscles and nerves of a frog that contracted when connected to a bimetallic conductor. The principle was later put into a practical application by Alessandro Volta who built in 1800, the first electrical cell, or battery, a series of metal disks of two kinds, separated by cardboard disks soaked with acid or salt solutions. This is the basis of all modern wet-cell batteries, and it was a tremendously important scientific discovery, because it was the first method found for the generation of a sustained electrical current.

One of the most prevalent problems associated with stray current or galvanic corrosion is the deterioration of submerged structural components on sea vessels. This is especially pronounced on components that are made of a soft metal, which will deteriorate more quickly than components made of a hard metal. In addition to the cost incurred to replace or fix damaged/destroyed components, there is also a significant safety risk that occurs when certain components are damaged/destroyed.

The corrosion potential of any metal is a voltage that can be measured by a reference electrode. Such measurements in water commonly are made with a silver/silver chloride reference electrode. The corrosion potential is a characteristic value for that metal, and it does matter if you have one metal component or 100, the corrosion potential stays the same.

There have been attempts to address the problem of stray current or galvanic corrosion. The most common solution is to add what is typically referred to as a sacrificial anode. The anodes are made of a metal that will attract electrolytes faster than a metal to which it is attached, thereby causing the anode to experience the destructive impact. While prior art sacrificial anodes are usually effective, many of the designs are not entirely practical and can be difficult to implement.

What is needed is a sacrificial anode that can be quickly and easily attached, and that will protect any structural component to which it is attached. Optimally, a sacrificial collar design, as disclosed herein, would be provided. A collar design would be easy to attach could be manufactured in a variety of shapes and sizes for use on many types of components both submerged in seawater and in other environments.

A search of the prior art did not disclose any literature or patents that read directly on the claims of the instant invention. However, the following U.S. patents are considered related:

PAT. NO.	INVENTOR	ISSUED
3,024,183	MacEwan	Mar. 6, 1962
3,152,059	Wellington	Oct. 6, 1964
4,391,567	Ciampolillo	Jul. 5, 1983

The U.S. Pat. No. 3,024,183 discloses a method producing sacrificial or consumable zinc anodes for use in inhibiting corrosion by galvanic action, and sacrificial zinc anodes that are use for the protection of metal structures and equipment such as heat exchangers, pipe lines, ship hulls, storage tanks and the like. In some instances, anodes are made in the form of cast blocks or slabs, with steel inserts to provide electrical contact between the anode and the metal structure to be protected, and also to provide means for fastening the anode to the metal structure to be protected.

The U.S. Pat. No. 3,152,059 discloses a method of making sacrificial or consumable zinc anodes for use in inhibiting corrosion by galvanic action and sacrificial zinc anodes produced for the protection from corrosion of metal structures and equipment such as heat exchangers, pipe lines, ships' hulls, storage tanks and the like. Sacrificial or consumable anodes are made in the form of cast blocks or slabs with steel inserts to provide electrical contact between the anode and the metal structure to be protected and, also, to provide means for fastening the anode to the structure.

The U.S. Pat. No. 4,391,567 discloses a corrosion preventing device for mounting in seawater on an electrically conductive propeller shaft supporting a marine propeller composed of a metal having a first galvanic potential. The device includes an annular washer having a generally circular periphery, composed of a metal having a second galvanic potential not greater than the first galvanic potential. The device further includes a generally toroidal anode having a circular periphery concentric with the axis, composed of a metal having a third galvanic potential greater than the first galvanic potential. The galvanic cell formed by the washer cathode and the toroidal anode maintains the propeller at a relative cathodic potential, thereby preventing the corrosion thereof in the seawater.

For background purposes and indicative of the art to which the invention relates, reference may be made to the following remaining patents found in the patent search.

PAT. NO.	INVENTOR	ISSUED
D474,161	M.ang.nsson et al	May 6, 2003
3,956,095	Khoo et al	May 11, 1976
3,994,794	Bohne	Nov. 30, 1976
4,190,512	Wyatt et al	Feb. 26, 1980
4,409,081	Terrase	Oct. 11, 1983
9,045,834	Lambourne	Jun. 2, 2015

DISCLOSURE OF THE INVENTION

In its basic design the sacrificial collar is comprised of a first section having a half-circle cavity and a matching second section having a half-circle cavity. The collar is preferably square or rectangular but can be any geometric shape, and is made of metal such as zinc, aluminum or magnesium, with zinc currently preferred. The first section and the second section are secured together around a structural component, with the component located within the cavities on the two sections. Typically, the structural component will be located on an environment where galvanic corrosion occurs such as within seawater. Therefore, the sacrificial collar is especially effective for use on sea vessel components that are submerged in seawater. Although this is the primary use, the sacrificial collar can also be utilized in other environments where corrosion can occur.

Once the two sections are secured together and onto a structural component, the sacrificial collar will attract the stray current or galvanic corrosion, instead of the stray current or galvanic corrosion being subjected to the structural component. The sacrificial collar will literally sacrifice itself to the stray current or galvanic corrosion, thereby protecting the structural component to which the collar is secured.

In view of the above disclosure, the primary object of the invention is to provide a sacrificial collar that is secured on a structural component to protect the component against stray current or galvanic corrosion.

In addition to the primary object, it is also an object of the invention to provide a sacrificial collar that:

• • is easy to secure,
  • is durable,
  • can be made in various shapes and sizes,
  • can be used on different types of structural components,
  • can lower insurance costs,
  • can increase safety,
  • can be sold as an OEM product or as an after-market product,
  • is user installable,
  • will not interfere with the operation or function of a component to which it is secure, and
  • is cost effective from both a manufacturer's and consumer's point of view.

These and other objects and advantages of the present invention will become apparent from the subsequent detailed description of the preferred embodiment and the appended claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an orthographic front view of a sacrificial collar with an upper section and a lower section attached together by bolt and nut combinations.

FIG. 2 is an orthographic side view of the sacrificial collar with the upper section and the lower section separated.

FIG. 3 is an elevational side view of the sacrificial collar secured on a structural component consisting of a shaft.

FIG. 4 is an orthographic front view of the sacrificial collar with corner cut-outs to allow an element such as seawater to freely pass over and across the collar.

FIG. 5 is an elevational side view of an oblong shaped sacrificial collar.

FIG. 6 is an orthographic front view of the sacrificial collar with attachment means in the form of a resilient band.

BEST MODE FOR CARRYING OUT THE INVENTION

The best mode for carrying out the invention is presented in terms that disclose a preferred embodiment of a sacrificial collar. Two of the most serious problems associated with the use of metal components are; first, stray current corrosion, and second, galvanic corrosion which is also known as bimetallic corrosion or dissimilar metal corrosion. These problems are especially prevalent for metal components that are located in seawater, such as submerged parts of a boat or other sea vessel.

Stray current corrosion occurs when metal with an electrical current flowing into it is immersed in water that is grounded (such as in any lake, river or ocean). The current can leave the metal and flow through the water to ground. This will cause rapid corrosion of the metal at the point where the current leaves. Stray direct current is particularly destructive. Stray current corrosion can cause rapid deterioration of the metal. If the metal happens to be aluminum, it can be destroyed in a matter of days.

Galvanic corrosion occurs when there are two different metals are physically or electrically connected and immersed in seawater, effectively creating a battery. Some amount of current flows between the two metals, and the electrons that make up that current are supplied by one of the metals giving up bits of itself in the form of metal ions to the seawater. The most common casualty of galvanic corrosion is a bronze or aluminum propeller on a stainless steel shaft, but metal struts, rudders, rudder fittings, outboards, and stern drives are also at risk. An example of this is a ship propeller that is made of bronze and zinc. When corrosion occurs the zinc in the propeller will deteriorate first, leaving zinc molecules in the bronze, which results in the remaining bronze being extremely fragile.

The way to counteract stray current or galvanic corrosion is to add a third metal into the circuit, one that is quicker than the other two to give up its electrons. The instant sacrificial collar can function as the third metal. While the sacrificial collar is predominantly used in seawater applications, there are instances of corrosion occurring in other locations. The design of the sacrificial collar allows the collar to be effectively utilized in many of these other instances. Additionally, the sacrificial collar can be secured on many types of structural components. For the purpose of this disclosure, the sacrificial collar is disclosed and shown secured on a circular object such as a shaft. Any modifications that would be necessary to facilitate the use of the sacrificial collar on other sizes/shapes of structural components is anticipated and thereby intended to be covered by this disclosure.

The sacrificial collar 10, as shown in FIGS. 1-6, can be made of various metals including zinc, aluminum or magnesium, with zinc currently preferred. The metal utilized for the sacrificial collar is specifically chosen due to the metal's ability to attract the stray current or galvanic corrosion that would otherwise affect the structural component(s). The sacrificial collar 10 can be any shape, but for the purpose of this disclosure a rectangular sacrificial collar 10 is primarily described and shown, along with an oblong sacrificial collar for reference.

As shown in FIGS. 1-4, the sacrificial collar 10 is comprised of a square or rectangular upper section 12 with a front surface 14, a rear surface 16, a right surface 18, a left surface 20, an upper surface 22, and a lower surface 24. Extending along the collar surface 24 is a half-circle cavity 28, and extending through one of at least two angularly opposed corners of the upper section from the upper surface to the lower surface is a bore 34.

A square or rectangular lower section 42 is a mirror image of the upper section 12, and is also comprised of a front surface 44, a rear surface 46, a right surface 48, a left surface 50, an upper surface 52 and a lower surface 54. Extending along the upper surface 52 is a half-circle cavity 58. It should be noted that the half-circle cavities 28,58 are only one possible shape. Other shapes such as square or triangular can also be utilized depending on the requirements of the application/function.

When the upper section 12 is mated to the lower section 42 the two respective half-circle cavities 28,58 create a single circular opening 60 that extends through the sacrificial collar 10 from the front surfaces 14,44 to the rear surfaces 16,46. Extending through one of at least two angularly opposed corners of the lower section 42 from the lower surface 54 to the upper surface 52 is a bore 64. The bores 34 on the upper section 12 are aligned with the bores 64 on the lower section 42.

The sacrificial collar 10 is secured on a circular structural component such as a shaft 86 by placing the upper section 12 on the shaft 86 such that one-half of the shaft's diameter is within the upper section's cavity 28 and then placing the lower section 42 on the shaft 86 such that the other half of the shaft's diameter is within the lower section's cavity 58. The sacrificial collar's two sections 12,42 are then secured on the shaft 86 by attachment means 70 that preferably comprise inserting a bolt 72 into each of the bores 34,64 and screwing a nut on the end of the bolt. Once the nut is tightened on the bolt, the two sections 12,14 are secured on the shaft 80, as shown in FIG. 3. Once secured, the sacrificial collar is subjected to stray current or galvanic corrosion thereby causing the collar 10 to deteriorate, instead of the shaft 80 (or other structural components to which the collar is secured) being subjected to stray current or galvanic corrosion which would cause the shaft 86 to deteriorate and would destroy the shaft 86.

In addition to the bolt and nut combination 72, the attachment means 70 for attracting the upper section 12 to the lower section 42, and that facilitates the securing the sacrificial collar 10 on a structural component, can be comprised of a screw 74, as shown in FIG. 1, that is inserted through at least one bore on the upper section and tightened into at least one corresponding tapped bore on the lower section 42.

Also, as shown in FIG. 6, the attachment means 70 can be comprised of at least one resilient band 76 that is placed around the upper and lower sections 12,42. The resiliency of the band 76 allows the band to maintain continuous and constant pressure on the sacrificial collar 10 even as the collar corrodes and deteriorates. As shown in FIG. 4, the sacrificial collar 10 can also include angular cut-outs 78 at each corner. The cut-outs 78 allow an element, such as seawater, to more freely pass over and across the sacrificial collar 10.

As previously disclosed, the sacrificial collar 10 is preferably square or rectangular, as shown in FIGS. 1-4. The collar 10 can also be other shapes such as circular or oblong 82, as shown in FIG. 5. The collar 10 is especially effective for use on structural components that are submerged in seawater. In addition, the sacrificial collar can also be used with equal efficacy on other components or items, or in other environments, including construction, water, oil, gas, liquid pipes, rebar protection, water heaters, heat exchangers, plumbing and underground utilities.

While the invention has been described in detail and pictorially shown in the accompanying drawings it is not to be limited to such details, since many changes and modification may be made to the invention without departing from the spirit and the scope thereof. Hence, it is described to cover any and all modifications and forms which may come within the language and scope of the claims.

Parts List
10 Sacrificial Collar
12 Upper Section
14 Front Surface
16 Rear Surface
18 Right Surface
20 Left Surface
22 Upper Surface
24 Lower Surface
26
28 Half Circle Cavity
30
32
34 Bore
36
38
40
42 Lower Section
44 Front Surface
46 Rear Surface
48 Right Surface
50 Left Surface
52 Upper Surface
54 Lower Surface
56
58 Half Circle Cavity
60 Opening
62
64 Bore
66
68
70 Attachment Means
72 Bolt and Nut Combination
74 Screw
76 Band
78 Cut-Out
80
82 Oblong
84
86 Shaft

Claims

1. A sacrificial collar that is placed on a structural component to protect against stray current or galvanic corrosion, wherein said sacrificial collar is comprised of a first section having a half-circle cavity and a second section having a half-circle cavity, wherein said first section and said second section are secured together and onto a structural component by attachment means, wherein said sacrificial collar is subjected to stray current or galvanic corrosion instead of the structural component to which said collar is secured being subjected to stray current or galvanic corrosion, which would destroy the structural component.

2. The sacrificial collar as specified in claim 1 wherein said sacrificial collar is made of a material selected from the group consisting of zinc, aluminum or magnesium.

3. The sacrificial collar as specified in claim 1 wherein said sacrificial collar is substantially square.

4. The sacrificial collar as specified in claim 1 wherein the structural component is located in seawater.

5. The sacrificial collar as specified in claim 1 wherein the structural component is attached to a sea vessel.

6. The sacrificial collar as specified in claim 5 wherein the structural component is circular.

7. The sacrificial collar as specified in claim 1 wherein said sacrificial collar is secured to the structural component by attachment means.

8. The sacrificial collar as specified in claim 7 wherein the attachment means is comprised of at least two bolt and nut combinations, wherein one bolt extends through corresponding bores on said first section and said second section.

9. A sacrificial collar that is placed on a structural component to protect against stray current or galvanic corrosion, wherein said sacrificial collar is comprised of:

a) a square upper section with a front surface, rear surface, a right surface, a left surface, an upper surface, and a lower surface, wherein extending along the lower surface is a half circle cavity, wherein extending through one of at least two angularly opposed corners of said upper section from the upper surface to the lower surface is a bore, and

b) a square lower section that is a mirror image of said upper section and comprised of a front surface, a rear surface, a right surface, a left surface, an upper surface, and a lower surface, wherein extending along the upper surface is a half circle cavity, wherein when said upper section is mated to said lower section the two respective half-circle cavities create a single circular opening that extends through said sacrificial collar from the front surface to the rear surface, wherein extending through one of at least two angularly opposed corners of said lower section from the lower surface to the upper surface is a bore, wherein the bores on said upper section are aligned with the bores on said lower section, wherein said sacrificial collar is secured onto a circular structural component by placing said upper section onto the structural component such that one-half of the structural component's diameter is within said upper section's cavity and placing said lower section onto the structural component's diameter such that the other half of the structural component is within said lower section's cavity, wherein said sacrificial collar's two sections are secured onto the structural component by inserting a bolt into each of the bores and screwing a nut onto the end of the bolt wherein once the nut is tightened onto the bolt, the two sections are secured on the structural component, wherein once secured, said sacrificial collar is subjected to stray current or galvanic corrosion thereby causing said collar to deteriorate, instead of the structural component to which said collar is secured subjected to stray current or galvanic corrosion which would cause the component to deteriorate and would destroy the component.

10. The sacrificial collar as specified in claim 9 wherein said sacrificial collar is made of a material selected from the group consisting of zinc, aluminum or magnesium.

11. The sacrificial collar as specified in claim 9 wherein the structural component is located in seawater.

12. The sacrificial collar as specified in claim 9 wherein the structural component is attached to a sea vessel.

13. The sacrificial collar as specified in claim 9 wherein the structural component is circular.

14. The sacrificial collar as specified in claim 9 wherein said collar is circular or oblong.

15. The sacrificial collar as specified in claim 9 wherein said collar is geometric shaped.

16. The sacrificial collar as specified in claim 9 wherein the attachment means further comprises a screw that is inserted through at least one bore on said upper section and tightened into at least one corresponding tapped bore on said lower section.

17. The sacrificial collar as specified in claim 9 wherein the attachment means further comprise at least one resilient band that is placed around said upper and lower sections, wherein the resiliency of the band allows the band to maintain continuous and constant pressure on said collar as said collar corrodes and deteriorates.

18. The sacrificial collar as specified in claim 9 further comprising angular cut-outs at each corner of said sacrificial collar, wherein the cut-outs allow an element to freely pass over and across said collar.

19. The sacrificial collar as specified in claim 18 wherein the element is seawater.