US2928411A

US2928411A - Structure for protecting metallic columnar elements

Info

Publication number: US2928411A
Application number: US448317A
Authority: US
Inventors: Wayne A Johnson
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-08-06
Filing date: 1954-08-06
Publication date: 1960-03-15
Anticipated expiration: 1977-03-15

Description

March 15, 1960 w. A. JOHNSON STRUCTURE FOR PROTECTING METALLIC COLUMNAR ELEMENTS Filed Au 6, 1954 INVENTOR. BY M"; M

Arm/Mfr Wayne A.

United States Patent 0 STRUCTURE FOR PROTECTING METALLIC COLUMNAR ELEMENTS Wayne A. Johnson, Houston, Tex. Application August 6, 1954, Serial No. 448,317

7 Claims. (Cl. 137-236) This invention relates to a structure for protecting metallic columnar elements from corrosion .or other deleteriousfeifects, such as the eifects resulting from the alternate exposure of the surfaces of such columns, as steel tubing, to salt water, and then to the moist, salt laden air immediately above salt water. This condition occurs as where pipe columns may rise, as from an oil well drilled ofi-shore.

Pipe lines have heretofore been protected by various means,as by coating and wrapping the pipe with alternate layers of materials, as felt and bitumastic. Otherwise, where this type of protection is not dictated, a type of protectionknown as cathodic protection may be employed. This type of protection consists in providing a material, as magnesium, which will serve as an anode when in electric storage battery relationship with the metal of the pipe, as steel, which will serve as the .cothode. This is achieved by mounting the magnesium at a spaced distance from the pipe, and applying a direct current potential between the magnesium anode and the pipe cathode with the result that the current, including that current set up by hydrolysis, will flow toward the pipe and not away therefrom. In this waycorrosion is inhibited, since the material of the pipe is not pitted or corroded away, but rather there is a tendency for the pipe to become protectively coated, as in the case of a conventional D.C. battery cathode. In the past :the practice has been to apply this system of cathodic pro- .tection to pipe which has also been process coated and wrapped, but the developed efficiency of cathodic pro- .tection methods in recent. years has resulted in ample protection in many cases without the additional process coating and wrapping of the pipe.

The methods heretofore employed, although generally effective when employed singly or in combination, have never been satisfactory to prevent corrosion in such cases as where a pipe or columnar element extends upwardly out of sea water. In such cases, due to the alternate exposure of the pipe surface to the sea water and then to the sea air, a tendency occurs toward increased hydrolysis in this area and to such a degree that normal cathodic protection methods cannot neutralize this tendency which results in the corroding away of the pipe in the range of levels affected by the tide. So far, this has not been successfully combatted by efforts to increase the cathodic protection in the vicinity of tide aifected levels, and supplemental ways have been sought to protect such vulnerable areas. To this end the invention which is the subject matter of this application has been perfected and successfully applied, the structure thereof being one readily installed at the levels where more complex structures would be difiicult to attach, and the methods employed serving to efiectively provide insulation at the desired site, and to adequate degree.

The object of this invention is to provide a structure to efiectively combat corrosion of columnar or tubular elements, as within the range of changing water levels.

It is also an object of this invention to provide a structure which will effectively-prevent corrosion in such areas, and a method of installing the same with the maximum efiiciency, and in the minimum time.

Other and further objects will be apparent when the specification is considered in connection with the drawings in which:

Fig. .1 is an elevation, part in section, showing the invention installed upon a pipe extending from below the water level.

Fig. 2 is a sectional of Fig. 1.

Fig. 3 is a fragmentary elevation, in perspective, showing a form of band fastener. employed in theinvention.

Fig. 4 is a sectional plan view of a modified form of the invention. f Fig. 5 is. asmall scale elevational view. showing the sheath of the invention in protective position on a riser from an under water pipe line to above the sea level; the pipe line extending from ashore.

Referring in detail to the drawings in which like reference numerals are applied to like elements in the various views, Fig. 1, shown partially by way of diagram, indicates a pipe line 15 which extends from'the shore .16 underwater at 17 to a point 18 where it joins a vertical plan view taken along line 2-2 pipe extension, thereof or riser 2 having an .insulative sheath thereon comprised of sections 1 whichcover the pipe riser 2 from a point above high tide level,

. The sheath or casing, of the insulator comprises two sections which are of plastic or of a similar material which is highlynon-conductive of'electric current and thus has a high di-electric constant, the, material of the sections also possessing water resistant properties, each section covering some bit over in are so that when the sections are installed about a round or columnar .element they overlap each other. To position the sections on a vertical riser in the form of a'metallic pipe or pipe extension 2 in a manner to provide an enclosed space between the sections and the pipe, seals 3v are provided at either end of the sections, and if the sections are of considerable length, it may be desirable to provide one or more spacers 4 or spoke members intermediate of, and spaced from the end seals. As shown in Fig. 2, this spacer 4 need be no more than a corrugated ribbon of 'suflicient strength to space the sections .ap'artfrom the pipe 2.

7 Any type of easily connectable band clip 7 may be 'used to connect the band ends 5 and 5' of the bands 6. Fig. 3 shows a form of such band end connection which includes an originally flat plate so slotted that the side flaps 7 may be bent over to extendbehind the re-curved inner end 5 of the band; the ears 8 may be bent over to extend between the re-curved outer end 5' of the band and the portion from which such end is re-curved; with ears 9 to be bent over outwardly to clasp the outer end 5' against such portion, and to clamp such portion against the portion from which the inner end 5 is recurved. The

band clip 7', are shown in the smaller scale of Figs. 21

bands 6 may be provided and passed through slots in the flanges to insure fastening.

A conventional fitting 12 shows as a small item in the r 1C6 patented Mar. s, 1960 i As an alternative construction,..-

scale on Fig. 1, such fitting being of conventional type,

ring of sealing material surrounding the riser, and means tightened, and clamp. latched about the two sections 1,

as hereinabove explained, a conduit is connected to a fitting 12 and the space between the riser or column 2 and the sections. 1 is. filled by pumping a mastic material, while inflowing state prior to hardening, through the conduit and through the fitting 1 2 to fill the space between riser or column 2 andnthesections 1. Such mastic material isshownin Figs. 1, 2, and 4 as the mastic 14 extending between the overlapping sections to harden andcomplete. the seal therein not-otherwise affected by the surface contact between the inter-connected sections.

As optional fillers, fiber glass'maybfe used-,in which to draw said. sections together to eifect the complete complemental surrounding of said riserby saidscctions and to bind said sectionsagainst said end seals and said end seals against said riser whereby the space defined by said sections, said end seals, and said riser is sealably enclosed, and a filler enclosed within said space and of a highly insulative, corrosion inhibitive material.

2. A protective sheath asclaimed in claim 1 in which a check valve having therein a valve element resiliently urged seated outwardly is provided in a section through which said filler may be injected under pressure to fill said space. Y

casesuch filler had best-be wrapped'aroundthe pi e be fore; the bands are installed. upon the sections'to bind such fiber glass; also, optionally grea'se maybe usedand pumped, as in the case of the mastic, to fill such space.

In its broader aspects thi's, invention has as its object the provision of a filler of highly'ins'ulative,{ non-conductive character, such "filler being water resistant and corrosion inhibitive, and providingtherewith an easily installed sheath of similarproperties having ahigh dielectric constant to enclose. the filler and provide therefor the space surrounding the. pipe or column, the location of such installation preferably being within elevations uponvertical columns which are within the lirnits of tidal change 'elevationson such column. 3

It is additionally stated that the inventione'mbracesja composite sleeve protecting columnar elements such as a pipe having its ends extending above and below the tidal zone respectively by mounting said sleeve around the pipe in said tidal zone to thereby protect the pipe 1' from corrosion. 7

What is claimed is: V l. The combination of a protective sheath anda-c'oluninar elementas a riser such as a pipe riser extending from a pipe line immersed in sea water to an elevation above high tide level, said sheath comprising longitudinally extending, water repellant, corrosion i'nhibitive, hi-dieleetric constant, insulator sections in longitudinal adjacency to complementally surround the riser in spaced relation therefrom and extending'from an elevation below low tide level to an elevation above high tide level, an end seal at the upper end of said sections and an end seal M the lower end thereof, each seal comprising a 3. A protective sheath as claimed in claim 1 in which said filler is selected from the group of fillers consisting of mastic, grease, and fiber glass.

4. A protective sheath as claimed in claim 1 in which said longitudinally extending side portions of saidsections overlap,circumferentially to eifect the complemental surrounding of said riser.

5. A protective. sheath as" claimed in claim I: in which an annular spacer; having axially extending opening t means. therethrough'is provided to space. said sections from said riser intermediate said end seals. t

6. A protective sheath as claimed in claim 1 in which the means to draw said sections together comprise a band for each end thereof, eachband having its ends interconnected by an inter-fitting clip. which quickly binds such ends against'peripheral slippage}, 7. Aprotective. sheath as claimed in, claiml in which said'sections have. longitudinally extending flanges extend-f ing radially outwardly from the, longitudinally extending edges thereof, the. flanges or adjacent section edges being interconnected to effect thecomplemental surrounding of said riser. w v p References; Cited. inthe file of this; patent UNITED snares. PATENTS 1,565,254' Bystrom Dec. 15, 1 925 1,871,508 Gardner Aug. 16, 1932; 1,948,007 Putnam Feb. 20, 1934 2,076210, Stadtfe1d Apr. 6, 1937 2,081,872 K'ahn et al. May 25, 193.7 2,360,109 Converse Oct. 10, 1944 12,791,096 Morton etal. May 7, i957 FOREIGN PATENTS. s

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