CATHODIC PROTECTION OF CONCRETE USING AN ANODE ATTACHED TO AN OUTER SURFACE.

Abstract

An anode apparatus for mounting on an external surface of a concrete structure to provide cathodic protection of metal members in the concrete uses a pre-assembled body which is typically elongate carrying a longitudinal anode, which can be sacrificial or impressed current, together with a supporting material having a front face for attachment to the surface and an impermeable plastic covering material at the rear face covering the anode and the supporting material when the front face is attached to the surface of the concrete. A channel defined on the front face is arranged to receive a layer of a conformable ionically conductive adhesive material for attachment to the external surface. A distance of the edge of the covering material is arranged to be similar to a distance of the metal from the external surface such that wetting and drying effects of environmental moisture are the same for the anode as for the metal components.

Claims

1. An anode apparatus which is pre-assembled for mounting on an external surface of a concrete structure to provide cathodic protection for one or more metal components within the concrete structure, the pre-assembled anode apparatus comprising: a body having a front face for attachment to the external surface and a rear face facing away from the concrete structure; an anode carried on the body; the anode being formed of a material which is sacrificial relative to the metal components to generate a galvanic current between the anode and the metal components to provide cathodic protection of said one or more metal components; an ionically conductive supporting material carried on the body and engaging the anode; the supporting material having a front face arranged to allow communication of ions from the anode through the supporting material to the metal components in the concrete; the body including an impermeable covering material at the rear face covering the anode and the supporting material; the impermeable covering material being arranged to cover the anode and the supporting material when the front face is attached to the surface of the concrete.

2. The anode apparatus according to claim 1 wherein there is provided a fastening arrangement for attachment of the front face to the surface.

3. The anode apparatus according to claim 2 wherein the fastening arrangement includes a channel for receiving an adhesive.

4. The anode apparatus according to claim 3 wherein the adhesive is arranged to attach between the supporting material and the surface

5. The anode apparatus according to claim 3 wherein the channel is defined by longitudinally extending spaced side edges arranged to confine the adhesive therebetween.

6. The anode apparatus according to claim 1 wherein the impermeable covering material has a raised center section under which the supporting material and anode is housed and two side depending flange sections for engaging the surface.

7. The anode apparatus according to claim 6 wherein the two depending side flange sections include a stop bead to contain an adhesive and an outer cover portion extending outwardly from the bead to cover adhesive escaping from the bead.

8. The anode apparatus according to claim 1 wherein the impermeable covering material includes flanges extending into and engaging the supporting material for maintaining the supporting material and the anode therein within the body.

9. The anode apparatus according to claim 1 wherein the impermeable covering material includes fastener holes through which screw fasteners can pass to engage the concrete.

10. The anode apparatus according to claim 1 including a separate end cover arranged to engage onto the impermeable covering material and cover one end of the body.

11. The anode apparatus according to claim 1 the end cover includes engagement lips for attachment to the impermeable covering material.

12. The anode apparatus according to claim 10 wherein the end cover is arranged to bridge across ends of two bodies.

13. The anode apparatus according to claim 10 wherein the anode includes one or more attachment wires for connection to said one or more metal components and wherein the end cover is arranged to cover said one or more attachment wires.

14. The anode apparatus according to claim 1 wherein there is provided an attachment alignment member for attachment of the body to the concrete which includes at least one mounting leg extending along the surface longitudinally of the elongate body for alignment and support of the body on the concrete.

15. The anode apparatus according to claim 1 wherein the impermeable body includes at least one cavity therein at the concrete surface to retain moisture.

16. An anode apparatus which is pre-assembled for mounting on an external surface of a concrete structure to provide cathodic protection for one or more metal components within the concrete structure, the pre-assembled anode apparatus comprising: a body having a front face for attachment to the external surface and a rear face facing away from the concrete structure; an anode carried on the body; the body including an impermeable covering material at the rear face covering the anode; and a channel defined on the body between the front face and the surface for receiving an adhesive material applied into the channel for attachment of the front face to the surface by the adhesive material; the impermeable covering material being arranged to cover the anode when the front face is attached to the surface of the concrete.

17-59. (canceled)

60. The anode apparatus according to claim 16 wherein the impermeable covering material extends beyond the anode and the adhesive material on either side.

61. The anode apparatus according to claim 16 wherein the adhesive material is wider than the anode.

62. The anode apparatus according to claim 16 wherein the adhesive material provides an area wider than the anode sealed on the concrete.

63. The anode apparatus according to claim 16 wherein the impermeable material includes at least one cavity therein at or adjacent the concrete surface which may be longitudinally extending.

64. The anode apparatus according to claim 63 wherein the cavity receives connecting wires related to the anode.

65. The anode apparatus according to claim 63 wherein the cavity is covered by a covering strip.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] FIG. 1 is an isometric view of one embodiment of an anode apparatus for mounting on the surface of a concrete structure for use in cathodic protection of steel components in the concrete structure, the anode apparatus being pre-manufactured and assembled prior to attachment to the structure and the anode apparatus including separate components for mounting, for covering wires from the anode and screw holes, and for acting as an end cap.

[0073] FIG. 2 is a cross-sectional view along the lines 2-2 of FIG. 1 showing the preassembled anode apparatus prior to attachment to the concrete surface.

[0074] FIG. 3 is cross-sectional view along the lines 3-3 of FIG. 1 showing the preassembled anode apparatus after attachment to the concrete surface.

[0075] FIG. 4 is cross-sectional view along the lines 4-4 of FIG. 1 showing the preassembled anode apparatus after attachment to the concrete surface and with the cover strips in place.

[0076] FIG. 5 is cross-sectional view along the lines 5-5 of FIG. 1 showing the preassembled anode apparatus after attachment to the concrete surface and showing the mounting bracket attached to the concrete surface and engaging the anode apparatus for alignment and support thereof.

DETAILED DESCRIPTION

[0077] The arrangement herein provides an anode apparatus 10 which is pre-assembled for mounting on an external surface 11 of a concrete structure 12 to provide cathodic protection for one or more metal components 13 within the concrete structure.

[0078] The apparatus includes a main body 14, a covering strip 15 which can be engaged onto the main body to cover mounting holes in the main body, a mounting strip 16 and an end cover panel 17. The covering strip 15 can also act to cover wires from the anode including connector wires, monitoring wires 151 and reference electrode wires 152 contained within a recess of yjr, som body 14 where required.

[0079] The main body 14 is best shown in cross-section in FIG. 2 and comprises a pre-assembled anode apparatus defining an elongate body having a front face 14A for attachment to the external surface 11 and a rear face 14B facing away from the concrete structure. The main body is primarily defined by an extruded strip 14C of an impermeable material such as a suitable plastic. The extruded strip can be of an electrically insulating material to cover any exposed conductors, but this is not essential. As the main body is typically extruded, it can be elongate in shape, but this is not necessarily so and it can be rectangular, square or even circular to surround an anode of similar shape.

[0080] The main body 14 has a raised center section 14D and two side wing sections 14E and 14F. within the raised section 14D is provided an elongate anode 14G carried on the elongate body and extending at least partly therealong. Typically the anode extends along the full length and includes connecting wires 14H and 14J at one or both ends for electrical connection to the steel, to the next anode and/or to a power supply as required.

[0081] In one embodiment, the anode is formed of a material such as zinc which is sacrificial relative to the metal components 13 to generate a galvanic current between the anode 14G and the metal components 13 to provide cathodic protection of the metal components. In another arrangement, the anode can be connected to a power supply so that it can optionally be of a non-sacrificial or inert material with the current for protection being provided by an impressed current rather than galvanically.

[0082] The anode is mounted in a supporting material of an ionically conductive material 14K carried on the elongate body and filling the raised section 14D so as to surround the anode which is thus embedded therein. The anode can be provided with recessed surface portions to increase the surface contact area between the anode and the supporting material 14K. The anode is located within the raised centersection of the plastic cover 14C and is spaced from the front face 14A. The supporting material is maintained in place by a pair of flanges or fins 14M projecting from the wall of the cover 14C inwardly into the body of the supporting material as it is cast in place within the cover and surrounding the anode.

[0083] In the case of an anode which is sacrificial, the supporting material 14K including an activator, of type well known to a person skilled in this art, is used for maintaining the galvanic current by promoting corrosion of the anode.

[0084] In the pre-assembled unit shown in FIG. 2, the supporting material has a front face defining the front face 14A which when mounted on the concrete surface acts to allow communication of ions from the anode through the supporting material to the metal components in the concrete.

[0085] The elongate body thus includes and is supported by the impermeable covering material 14C at the rear face of the body where the material 14C covers the anode and the supporting material. The impermeable covering material is arranged to cover the anode and the supporting material when the front face is attached to the surface of the concrete. This impermeable covering material separates the anode and the supporting material from the environment including any surrounding moisture from rain, splashing and tidal action.

[0086] The anode apparatus shown in FIG. 2 is arranged to be handled, transported and installed as a common assembly with the structure being sufficiently robust to accommodate the forces involved while maintaining the structure as an elongate linear body. The structure can be formed in different lengths if required for particular installations or can be connected end to end as discussed hereinafter.

[0087] The structure is arranged to be mounted on the front face of the concrete as a standalone body leaving other parts of the surface exposed. It is of course important that the front face of the supporting material is in intimate ionic contact with the surface of the concrete to ensure effective ion communication between the anode and the steel. For this purpose, the main attachment is provided by a layer 14N of an adhesive material. This is flexible or conformable when applied so as to accommodate variations in the surfaces and is arranged to cure after installation to form an integral body between the concrete surface and the elongate body including the anode. In one preferred arrangement, the adhesive material can be applied by trowelling material onto the front face 14A to a required thickness following which the anode apparatus is applied onto the surface. The adhesive material may be a suitable cement based mortar, but can include other materials which are conformable, adhesive and ionically conductive.

[0088] The fastening arrangement includes a channel 14P for receiving the adhesive defined by two flanges or beads 14R projecting downwardly from the front face by a height equal to the desired thickness of the adhesive. This provides therefore a guide for the user to apply the adhesive to the required thickness. The adhesive is thus arranged to attach between the supporting material and the surface.

[0089] As an alternative not shown, the adhesive can be proved as a part of the anode apparatus as a pre-applied layer and covered by a release sheet.

[0090] The impermeable covering material thus has the raised center section under which the supporting material and anode is housed and two side sections 14S for engaging the surface on either side of the supporting material. The wall sections extend outwardly from the raised section to outer edge 14T. the beads 14R extend downwardly from the walls 14S at a position spaced outwardly from an inner edge of the wall 14S so that a part of the wall 14S is attached to the surface of the concrete by the adhesive layer 14N. The wall sections 14S extend outwardly from the beads 14R along the surface of the concrete to cover any adhesive escaping from the bead due to pressure or slight overfilling used to ensure full coverage.

[0091] The cover 14 further includes stiffening cavities 14X on each side of the raised center 14D and inward of the channels 14Y which receive the wires 151 and the fastening screws to be covered by the strips 15. In this way the extruded cover is relatively stiff and can lie flat on the surface of the concrete with the underside of the material 14K and the underside surface 14S bonded to the surface of the concrete by the applied adhesive layer.

[0092] In order to provide a more secure attachment of the elongate body and to hold the body in place during and after curing of the adhesive, the impermeable covering material includes fastener holes 14U at locations thereon outward of the beads 14R so as to be outward of the adhesive and spaced from the supporting material 14K. The holes allow screw fasteners to pass to engage into the concrete.

[0093] In order to provide a fully attractive and smooth rear face exposed on the concrete surface, the insert strips 15 engage over the holes and are retained on the body as a snap fit or as a sliding fit at the channels 14Y with cooperating projections 14V which locate the strip in the channel. These can also cover the wires as described above which can be retained, protected and hidden by the insert strips.

[0094] As shown in FIGS. 1 and 5 the separate end cover 17 is provided and arranged to engage onto the impermeable covering material and cover an end face of the impermeable covering material at one end of the elongate body. The cover 17 has an interior shape matching the exterior of the elongate body and the cover material thereof and includes engagement lips 171 for attachment to the impermeable covering material at recesses 172 at the end of the elongate body. This can slide into place from the end or can snap over the sides of the body. The end cover can be used to bridge across ends of two end to end elongate bodies (not shown) and to cover the attachment wires at one end of the anode for connection to the metal components.

[0095] As an option to provide simple mounting of the elongate body on the concrete surface, there is provided the attachment member 16 for attachment to the concrete prior to the mounting of the body on the concrete. This can be mounted at set locations to act as a guide to properly align and locate the body. This includes at least one mounting leg 16A which when attached extends along a portion of the surface longitudinally of the intended location of the elongate body for attachment to and support of the elongate body when applied on the concrete. Thus the attachment member is mounted at an intended location of one end of the body following which the body is slid into place on the leg 16A with the leg being received in a receptacle 14W in the body between the outer edge 14T and the bead 14R. The impermeable body may include at least one longitudinally extending cavity or channel therein which can be defined by the receptacle 14W which is located at the concrete surface to retain moisture passing along the body after installation to help maintain moisture at the support material 14K which maintains galvanic activity. The outer edges 14T at the recesses 172 can provide a location for an additional sealing bead of sealant or calking material (not shown).

[0096] The arrangement herein can be used in a method where the predetermined distance D1 between the surface of the concrete and the steel 13 is arranged to match said predetermined distance D2 between the edge of the cover 14C and the anode 14G at the center of the cover at such that wetting and drying effects are the same for the anode as for the metal components.