GB2161886A - Protection of tubular steel structures from corrosion - Google Patents
Protection of tubular steel structures from corrosion Download PDFInfo
- Publication number
- GB2161886A GB2161886A GB08517570A GB8517570A GB2161886A GB 2161886 A GB2161886 A GB 2161886A GB 08517570 A GB08517570 A GB 08517570A GB 8517570 A GB8517570 A GB 8517570A GB 2161886 A GB2161886 A GB 2161886A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sheet
- cover
- tubular steel
- cover sheet
- steel structure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 19
- 239000010959 steel Substances 0.000 title claims abstract description 19
- 230000007797 corrosion Effects 0.000 title claims abstract description 13
- 238000005260 corrosion Methods 0.000 title claims abstract description 13
- 239000000463 material Substances 0.000 claims abstract description 15
- 239000004264 Petrolatum Substances 0.000 claims abstract description 13
- 229940066842 petrolatum Drugs 0.000 claims abstract description 13
- 235000019271 petrolatum Nutrition 0.000 claims abstract description 13
- 239000000945 filler Substances 0.000 claims abstract description 11
- 229920005992 thermoplastic resin Polymers 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 25
- -1 polyethylene Polymers 0.000 claims description 8
- 230000000295 complement effect Effects 0.000 claims description 6
- 239000004698 Polyethylene Substances 0.000 claims description 4
- 229920000573 polyethylene Polymers 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 3
- 239000006260 foam Substances 0.000 abstract 1
- 229910001369 Brass Inorganic materials 0.000 description 3
- 239000004677 Nylon Substances 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 3
- 239000010951 brass Substances 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 229920001778 nylon Polymers 0.000 description 3
- 229920001155 polypropylene Polymers 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 3
- 238000005553 drilling Methods 0.000 description 2
- 239000003365 glass fiber Substances 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 229920001225 polyester resin Polymers 0.000 description 2
- 239000004645 polyester resin Substances 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- QTCANKDTWWSCMR-UHFFFAOYSA-N costic aldehyde Natural products C1CCC(=C)C2CC(C(=C)C=O)CCC21C QTCANKDTWWSCMR-UHFFFAOYSA-N 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- ISTFUJWTQAMRGA-UHFFFAOYSA-N iso-beta-costal Natural products C1C(C(=C)C=O)CCC2(C)CCCC(C)=C21 ISTFUJWTQAMRGA-UHFFFAOYSA-N 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000012764 mineral filler Substances 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 229940038692 petrolatum paste Drugs 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000009991 scouring Methods 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
- F16L58/02—Protection of pipes or pipe fittings against corrosion or incrustation by means of internal or external coatings
- F16L58/04—Coatings characterised by the materials used
- F16L58/10—Coatings characterised by the materials used by rubber or plastics
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Revetment (AREA)
Abstract
A tubular steel structure 8 is protected from corrosion by a petrolatum tape or sheet which is wrapped around the structure, a layer of foam filler material 9 applied thereto and the filler material thereafter encased with one or more cover sheets 1 of a flexible thermoplastic resin. The cover sheet(s) 1 have two sets of holes through which a fastener 5 passes to join the edges of the cover sheet 1 together. <IMAGE>
Description
SPECIFICATION
Method for the protection of tubular steel structures from corrosion
The present invention relates to a method for the protection of tubular steel structures from corrosion. In particular, the invention is concerned with the protection from corrosion of tubular steel members, preferably of circular, hexagonal or square cross section, which are exposed to a marine environment, i.e., which are immersed partially, or completely, in sea water or are within the splash zone above sea leval, or which are exposed to estuarine or fresh water, e.g. in rivers, lakes, harbours and docks.
In recent years, costal and off-shore structures, such as jetties, oil drilling platforms etc., have been constructed from tubular members and the protection of these members from corrosion has constituted a major problem. Whilst it has long been established that petrolatum tape will provide long-term protection from corrosion to steel surfaces exposed to a marine environment, the practical problem has remained of maintaining the soft protective membrane intact. In coastal areas, the scouring action of waves is very severe and damage is also caused by shingle bombardment. On off-shore structures damage is also caused to some extent by waves but is mainly caused by floating debris.
An improved form of mechanical protection for the petrolatum tape has recently been developed, the outer protective layer of which consists of preformed semi-circular sections of glass fibre reinforced polyester resin. These preformed semic-circular sections are provided with longuitudinal flanges which are bolted together to form a circular cover. The space between the outer cover and the protective tape is filled with a layer of foamed polyethylene sheet which is compressible and accommodates any irregularities of the space when the flanges are bolted together. Whilst this method has proved quite effective in giving long-term protection, it suffers from the disadvantage that the cost of the glass fibre reinforced polyester resin covers is high and special sections have to be manufactured for each size of profile to be protected.The overall cost of this system has therefore limited the number of occasions on which it has been used.
We have now developed an improved method for the mechanical protection from corrosion of tubular steel structures which is cheaper than the method described above.
Accordingly, the present invention provides a method for the mechanical protection from corrosion of a tubular steel structure which method comprises wrapping a petrolatum tape or sheet around the steel structure, applying a layer of a filler material to the petrolatum tape or sheet and thereafter encasing the filler material with one or more cover sheets of a flexible thermoplastic resin the or each cover sheet being provided at one edge thereof with a plurality of openings and at the other edge thereof with a plurality of complementary openings and the cover sheet or plurality of cover sheets being secured in position by fastening means which pass through the openings and the complementary openings.
The tubular steel structure may be of any regular cross section although it will generally be of circular, hexagonal or square cross section. It will be understood that for non-circular sections two or more cover sheets may be employed which are joined together at the edges thereof by the fixing method described.
Futhermore, the cover sheets may be preformed with appropriate bends at predetermined intervals so that fewer sheets are required to encase a tubular steel structure which is non-circular. Alternatively, longitudinal grooves may be formed in the cover sheets at predetermined intervals to form hinges to assist conformation to the shape of the tubular structure.
Petrolatum tape is a non-woven fabric tape which is made from a synthetic fibre which is impregnated with and coated with an anticorrosive composition, the main components of which are a saturated paraffinic hydrocarbon and inert mineral fillers. Petrolatum tape is generally available in a variety of widths.
Petrolatum sheet is a similar material generally available in widths up to about 1 metre.
If desired, the tubular steel structure which is to be treated by the method of the invention may first be coated with an anti-corrosive composition such as petrolatum paste.
The filler material is applied between the petrolatum tape or sheet wrapping and the flexible thermoplastic resin cover sheet in order to accommodate any irregularities of the space when the fastening means are tightened. The filler material is preferably foamed polyethylene sheet.
The cover sheet may be made of any suitable thermoplastic resin, for example, polypropylene. Preferably the cover sheets are provided at one edge thereof with circular bolt holes and at the other edge thereof with complementary elongate holes, the cover sheet being secured in position by suitable fastening means which pass through these holes. The provision of elongate holes at one edge of the cover sheet enables the sheets to be adapted to be wrapped around tubular steel structures of different circumferences and also to enable any variations in the circumference of the surface of a single structure to be readily accommodated. The cover sheets can be made up on site to the required dimensions by cutting and drilling, or may be supplied prefabricated to the required dimensions.
The fastening means used to secure the
cover may be for example nuts, bolts and washers. It has been found particularly useful to employ one or more bolts incorporated into anchor plates, cooperating clamp plates through which the bolts pass and nuts to tighten onto the bolts. The fastening means, e.g., bolts, nuts and anchor plates, should be
made of a corrosion resistant material such as
brass, nylon or other plastics material.
To assist during installation the cover sheet
is generally clamped tightly around the tubular steel member by means of temporary
bands or straps or the like which may be
made from a corrosion resistant material such as brass or from a strong non-metallic material such as nylon in the form of webbing. The straps are removed after the fastening means referred to above have been secured.
Additionally, locating bands may be provided at the top and bottom of the formed protective jacket to prevent the jacket from sliding up or down on pile due to weight or buoyancy. For tubular members of circular cross-section the locating bands may be formed from two semi-circular sections with lugs or flanges each side to allow them to be fastened together. The locating bands may be made from a corrosion resistant material such as brass, nylon or polypropylene. The locating bands are clamped directly onto the pile above and below the section provided by the cover.
The present invention will be further described with reference to a specific embodiment thereof as shown in the accompanying drawings, in which:
Figure 1 is a plan view of the cover sheet used in the method of the invention;
Figure 2 is a side view of an anchor plate which forms part of the fastening means used in the method of the invention;
Figure 3 is a plan view of a clamp plate which also forms part of the fastening means used in the method of the invention; and
Figures 4, 5 and 6 show, in horizontal section through a marine pile, the assembly method used in the present invention.
Referring to Fig. 1 of the drawings, a rectangular polypropylene cover sheet 1 has a plurality of bolt holes 2 formed along one edge thereof and a plurality of elongate holes 3 formed along the other edge thereof.
Fig. 2 shows an anchor plate 4 which forms a part of the fastening means used in the method of the invention. The anchor plate 4 has two bolts 5 projecting perpendicularly therefrom. Fig. 3 shows the clamp plate 6 which has two holes 7 through which bolts 5 are able to pass.
Referring to Figs. 4, 5 and 6, a marine pile 8 which is wrapped with petrolatum tape (not shown) has a layer of foamed polyethylene 9 wrapped therearound as a filler material. To secure the cover sheet to the protected marine pile anchor plates 4 (only one of which is shown in the sectional drawings) are positioned vertically along the pile. The bolts 5 on the anchor plates are passed through the elongate holes 3 on one edge of the cover sheet. The cover sheet 1 is wrapped around the filler 9 until the circular holes 2 on the other edge thereof are aligned with the bolts
5, whereupon they are passed over the bolts
5 as shown in Fig. 5. The cover sheet 1 is then secured around the protected marine pile by fitting clamp plates 6 over the bolts in the corresponding anchor plates and thereafter tightening nuts 10 onto the bolts 5.
Claims (10)
1. A method for the mechanical protection from corrosion of a tubular steel structure which method comprises wrapping a petrolatum tape or sheet around the steel structure, applying a layer of a filler material to the petrolatum tape or sheet and thereafter encasing the filler material with one or more cover sheets of a flexible thermoplastic resin the or each cover sheet being provided at one edge thereof with a plurality of openings and at the other edge thereof with a plurality of complementary openings and the cover sheet or plurality of cover sheets being secured in position by fastening means which pass through the openings and the complementary openings.
2. A method as claimed in claim 1 wherein the tubular steel structure is of circular cross-section and a single cover sheet is used to encase the said structure.
3. A method as claimed in claim 1 or claim 2 wherein the tubular steel structure is coated with an anti-corrosive composition before the petrolatum tape or sheet is wrapped therearound.
4. A method as claimed in any one of the preceding claims wherein the filler material is foamed polyethylene sheet.
5. A method as claimed in any one of the preceding claims wherein the cover sheet or cover sheets is/are made from a thermoplastic resin.
6. A method as claimed in any one of the preceding claims wherein the cover sheet or cover sheets is/are provided at one edge thereof with circular bolt holes and at the other edge thereof with complementary elongate holes.
7. A method as claimed in any one of the preceding claims wherein the cover sheet or cover sheets is/are provided with longitudinal grooves which form hinges.
8. A method as claimed in any one of the preceding claims wherein the tubular steel structure is of non-circular cross-section and a plurality of cover sheets are used to encase the said structure.
9. A method as claimed in any one of the preceding claims substantially as hereinbefore described.
10. A method as claimed in claim 1 substantially as hereinbefore described with reference to any one of the figures of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB848418340A GB8418340D0 (en) | 1984-07-18 | 1984-07-18 | Protection of tubular steel structures from corrosion |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8517570D0 GB8517570D0 (en) | 1985-08-14 |
| GB2161886A true GB2161886A (en) | 1986-01-22 |
| GB2161886B GB2161886B (en) | 1987-07-15 |
Family
ID=10564082
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB848418340A Pending GB8418340D0 (en) | 1984-07-18 | 1984-07-18 | Protection of tubular steel structures from corrosion |
| GB08517570A Expired GB2161886B (en) | 1984-07-18 | 1985-07-11 | Protection of tubular steel structures from corrosion |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB848418340A Pending GB8418340D0 (en) | 1984-07-18 | 1984-07-18 | Protection of tubular steel structures from corrosion |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB8418340D0 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102017129195A1 (en) * | 2017-12-07 | 2019-06-13 | Nkt Gmbh & Co. Kg | Connecting sleeve for connecting cable ends of two cables, in particular submarine cables without solderable cable sheath |
-
1984
- 1984-07-18 GB GB848418340A patent/GB8418340D0/en active Pending
-
1985
- 1985-07-11 GB GB08517570A patent/GB2161886B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102017129195A1 (en) * | 2017-12-07 | 2019-06-13 | Nkt Gmbh & Co. Kg | Connecting sleeve for connecting cable ends of two cables, in particular submarine cables without solderable cable sheath |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8418340D0 (en) | 1984-08-22 |
| GB8517570D0 (en) | 1985-08-14 |
| GB2161886B (en) | 1987-07-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19940711 |