COATED POST

Abstract

A method of extending the corrosion resistance of a ground anchoring region of a steel or alloy fence or trellis post already having a sacrificial coating or non-sacrificial coating along an entire length of the fence or trellis post, said method including the step of applying at least one additional coating to the ground anchoring region so as to extend the corrosion resistance of the ground anchoring region. The at least one additional coating can be a sacrificial coating and/or non-sacrificial coating.

Claims

1. (canceled)

2. (canceled)

3. (canceled)

4. (canceled)

5. (canceled)

6. A coated steel or alloy post comprising a sacrificial coating or non-sacrificial coating extending along an entire length of the post, and comprising at least one additional coating on a ground anchoring region of the post; wherein the post is a fence post that is T or Y-shaped when viewed in end elevation.

7. The coated steel or alloy post of claim 6, wherein the post has a ground anchoring region and a non-ground anchoring region, wherein the sacrificial coating or non-sacrificial coating is a galvanized coating, and wherein the ground anchoring region comprises the at least one additional coating which does not extend beyond the ground anchoring region or extends from the ground anchoring region partway along the non-ground anchoring region.

8. The coated steel or alloy post of claim 6, wherein the post has a ground anchoring region and a non-ground anchoring region, and wherein the ground anchoring region comprises the at least one additional coating which does not extend beyond the ground anchoring region or extends from the ground anchoring region partway along the non-ground anchoring region.

9. (canceled)

10. (canceled)

11. The post of claim 8, wherein a small region of the non-ground anchoring region of the post, immediately adjacent the ground anchoring region comprises the at least one additional coating.

12. The post of claim 8, wherein the non-ground anchoring region comprises at least one post member attachment point, and wherein the non-ground anchoring region comprises the at least one additional coating on a region extending said between at least one post member attachment point, situated closest to the ground anchoring region, and the ground anchoring region.

13. The post of claim 12, wherein the non-ground anchoring region comprises the at least one additional coating on a region extending from the ground anchoring region to a point just beyond the at least one post member attachment point, situated closest to the ground anchoring region.

14. The post of claim 13, wherein the at least one additional coating extends from the ground anchoring region to approximately 50 mm beyond the at least one post member attachment point, situated closest to the non-ground anchoring region.

15. (canceled)

16. (canceled)

17. (canceled)

18. (canceled)

19. (canceled)

20. The post of claim 6, wherein the at least one additional coating extends along the entire length of the post.

21. (canceled)

22. The post of claim 6, wherein the post is a steel fence post.

23. The post of claim 6, wherein the at least one additional coating is a sacrificial coating.

24. The post of claim 23, wherein the sacrificial coating comprises zinc, aluminium, zinc-aluminium alloy, zinc-nickel alloy, steel, titanium, copper, nickel, stainless steel, tin, nickel-chromium, acrylate, wax, clear polymer or a biopolymer.

25. (canceled)

26. (canceled)

27. The post of claim 6, wherein the at least one additional coating is a non-sacrificial coating.

28. The post of claim 27, wherein the non-sacrificial coating is conductive or non-conductive.

29. The post of claim 27, wherein the non-sacrificial coating is impervious to moisture; or wherein the non-sacrificial coating is impervious to water and oxygen.

30. (canceled)

31. The post of claim 27, wherein the non-sacrificial coating comprises an organic coating, paint coating, epoxy resin coating, bitumin coating, thermoplastic coating, rubber coating, plastic coating, ceramic coating, or shrinkable sleeve.

32. The post of claim 27, wherein the non-sacrificial coating comprises single polymers, copolymers or a combination of polymers, or copolymers and metals

33. (canceled)

34. (canceled)

35. The post of claim 6, wherein the at least one coating comprises a non-sacrificial outer coating covering a sacrificial second coating, which in turn coats a hot galvanised innermost coating of the post.

36. (canceled)

37. The post of claim 6, wherein the post comprises two sacrificial coatings.

38. The post of claim 37, wherein an ungalvanised steel or alloy post is first coated with zinc, and then with a further coating of zinc, aluminium or zinc-aluminium alloy.

39. (canceled)

40. (canceled)

41. The post of claim 6, wherein the post is an agricultural post.

Description

BRIEF DESCRIPTION OF FIGURES

[0098] FIG. 1 illustrates various coated steel agricultural posts (i to xxx), produced according to methods of the present invention.

[0099] FIG. 2 is a flow chart depicting how steel agricultural fence posts are usually manufactured.

[0100] FIG. 3 is a flowchart depicting the manufacture of coated steel fence posts, according to various embodiments of the present invention.

[0101] FIG. 4 is a flowchart depicting the manufacture of coated steel fence posts, beginning with galvanised fence posts, according to an embodiment of the present invention.

[0102] FIG. 5 is a flowchart depicting the manufacture of coated steel fence posts, beginning with galvanised fence posts, according to an embodiment of the present invention.

[0103] FIG. 6 depicts an in-line method for preparing, drying and applying an additional sacrificial coating or non-sacrificial coating to a fence post, according to an embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

[0104] Although this Best Modes section mostly describes fence posts, it is to be understood that, context permitting, this section may equally apply to trellis posts or other steel or alloy post types used in agriculture. It may also apply to aluminium posts.

[0105] The inventor has found that powder coated or passive coated (painted) posts provide no further corrosion protection to the steel substrate once the surface is broken through or breached. Zinc coatings (active/sacrificial coatings) on posts start working from the moment they are placed in the ground. By adding at least one additional non-porous/impervious membrane or coating over the zinc coated posts their “life sacrificing actions” are delayed from commencing—and may never be called upon to start sacrificing should the impervious barrier never be breached. By adding a third coating that offers an even longer sacrificial lifespan (zinc-aluminium alloy, for example), that middle coating will only ever be “called up for service” to start sacrificing only if the outermost coating is breached.

[0106] Again, the inventor has discovered that the working life of an agricultural steel or alloy post having a sacrificial coating or non-sacrificial coating extending along an entire length of the post can be extended by increasing corrosion protection to the ground anchoring region of the post. This is achieved by applying at least one additional coat/coating of a sacrificial and/or non-sacrificial (passive/barrier) nature to the ground anchoring region. Preferably, in the case of a fence post, the at least one additional coat/coating is further applied to/extends from the ground anchoring region to approximately 50 mm beyond a first fence member attachment point/region (situated closest to the ground anchoring region).

[0107] In some preferred embodiments, a fully galvanised fence post further has at least one additional sacrificial and/or non-sacrificial (passive/barrier) coating applied to its ground anchoring region. Preferably, the at least one additional coat/coating is further applied to/extends from the ground anchoring region to approximately 50 mm beyond a first fence member attachment point/region (situated closest to the ground anchoring region).

[0108] In other preferred embodiments, a fence post having a length-long passive coating further has at least one additional sacrificial and/or non-sacrificial (passive/barrier) coating applied to its ground anchoring region. Preferably, the at least one additional coat/coating is further applied to/extends from the ground anchoring region to approximately 50 mm beyond a first fence member attachment point/region (situated closest to the ground anchoring region).

[0109] In yet other preferred embodiments, a sacrificial coating or non-sacrificial coating is first applied to the entire length of a previously untreated steel fence post, and then at least one additional sacrificial and/or non-sacrificial (passive/barrier) coating is then applied to the ground anchoring region of the treated fence post. Preferably, the at least one additional coat/coating is further applied to/extends from the ground anchoring region to approximately 50 mm beyond a first fence member attachment point/region (situated closest to the ground anchoring region).

[0110] Referring first to FIG. 2, that figure depicts how agricultural steel fence posts are usually produced. Black untreated steel posts are: manufactured 2 and may or may not contain fence member attachment points. The posts are further processed so as to incorporate holes, openings, slots or other types of fence member attachment points 3. The posts are then prepared by way of pickling, mechanical cleaning, ultrasonic cleaning or other suitable preparation treatment 4. The posts are then hot dipped galvanised and subjected to passivation-quenching treatment 5. Finally, the posts are assembled and packaged for sale 6.

[0111] As seen in FIG. 1, each post 1 (i to xxx) has a ground anchoring region 10 and a non-ground anchoring region 11. Each post 1 usually has one or more fence member anchoring points 40 located along the non-ground anchoring region 11. To these are mounted clips, retainers, wires and other types of fence members/accessories.

[0112] Referring now to FIGS. 3, 4 and 5, each of those figures depicts the present innovative process according to embodiments of the present invention. First, a galvanised post 1a, 1b having a sacrificial coating is suitably prepared for further treatment. In particular, the ground anchoring region 10a, 10b of the post 1a, 1b plus an adjacent short region of the non-ground anchoring region 11a, 11b (approximately 50 mm above a first fence member attachment point/region) are suitably prepared without damaging or reducing the existing sacrificial coating on the non-ground anchoring region 11a, 11b that is located above the ground, and without substantially reducing the thickness of the sacrificial coating on the ground anchoring region 10a, 10b.

[0113] After the step of suitable preparation 20b, according to a first embodiment (also depicted in FIG. 5), the ground anchoring region 10b plus an adjacent short region of the non-ground anchoring region 11b (approximately 50 mm above a first fence member attachment point/region) are heated to a temperature between about 150° and 350° C. 21b, following which the ground anchoring region 10b plus the adjacent short region of the non-ground anchoring region 11b are dipped into a fluidised bed of secondary coating material for approximately 2-7 seconds 22b. The post 1b is then removed and cured at approximately 150 to 190° C. 23b. In this way, a coated post 1b is produced, as shown in FIG. 1.

[0114] After the step of suitably preparing the posts 20a, according to a second embodiment (also depicted in FIG. 4), the ground anchoring region 10a plus an adjacent short region of the non-ground anchoring region 11a are subjected to an electrostatic powder coating step 21a. The post 1a (all of the post 1a or just the ground anchoring region 10a plus the adjacent short region of the non-ground anchoring region 11a) is heated to between about 130 and 220° C. 22a. In this way, a coated post is produced 1a, as shown in FIG. 1.

[0115] FIG. 6 shows an in-line method for preparing, drying and applying an additional sacrificial coating or non-sacrificial coating to a fence post 1, according to an embodiment of the present invention. The method utilises rollers 20 of a conveyor which convey the fence post 1 through a washing/surface preparation station 21, a drying station 22, and a spray coating station 23. The coating station 23 has spray nozzles 24 that are able to coat all surfaces of the fence post 1.

[0116] Advantages of the present invention as exemplified include: that the corrosion resistance of a ground anchoring region of a steel agricultural post can be extended, thereby potentially increase the working life of the whole post; and, that this can be achieved in a cost effective manner.

[0117] Throughout this specification, unless in the context of usage an alternative interpretation is required, the term “comprise” (and variants thereof such as “comprising” and “comprised”) denotes the inclusion of a stated integer or integers but does not exclude the presence of another integer or other integers.

[0118] Any reference to publications cited in this specification is not an admission that the disclosures constitute common general knowledge in Australia or in other countries.

[0119] It will be appreciated by one of skill in the art that many changes can be made to the composition and uses exemplified above without departing from the broad ambit and scope of the invention.