US3462962A - Prevention of corrosion of metal pipes placed underground - Google Patents
Prevention of corrosion of metal pipes placed underground Download PDFInfo
- Publication number
- US3462962A US3462962A US591391A US3462962DA US3462962A US 3462962 A US3462962 A US 3462962A US 591391 A US591391 A US 591391A US 3462962D A US3462962D A US 3462962DA US 3462962 A US3462962 A US 3462962A
- Authority
- US
- United States
- Prior art keywords
- soil
- admixture
- pipe
- lime
- ditch
- 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.)
- Expired - Lifetime
Links
- 229910052751 metal Inorganic materials 0.000 title description 14
- 239000002184 metal Substances 0.000 title description 14
- 238000005260 corrosion Methods 0.000 title description 8
- 230000007797 corrosion Effects 0.000 title description 8
- 230000002265 prevention Effects 0.000 title 1
- 239000002689 soil Substances 0.000 description 33
- 239000004571 lime Substances 0.000 description 16
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 12
- 235000011941 Tilia x europaea Nutrition 0.000 description 12
- 239000004927 clay Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000004210 cathodic protection Methods 0.000 description 5
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 4
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 4
- 235000011116 calcium hydroxide Nutrition 0.000 description 4
- 239000000920 calcium hydroxide Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 238000007596 consolidation process Methods 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000007792 addition Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- IHPYMWDTONKSCO-UHFFFAOYSA-N 2,2'-piperazine-1,4-diylbisethanesulfonic acid Chemical compound OS(=O)(=O)CCN1CCN(CCS(O)(=O)=O)CC1 IHPYMWDTONKSCO-UHFFFAOYSA-N 0.000 description 1
- 239000007990 PIPES buffer Substances 0.000 description 1
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 239000003209 petroleum derivative Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F5/00—Dredgers or soil-shifting machines for special purposes
- E02F5/02—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches
- E02F5/10—Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for reinforcing trenches or ditches; with arrangements for making or assembling conduits or for laying conduits or cables
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B41/00—Equipment or details not covered by groups E21B15/00 - E21B40/00
- E21B41/02—Equipment or details not covered by groups E21B15/00 - E21B40/00 in situ inhibition of corrosion in boreholes or wells
-
- 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
Definitions
- ABSTRACT OF THE DISCLOSURE o be employed to the extent of 5 to 20 percent by weight of the admixture of lime and the original soil if there is insufficient clay in the original soil to yield the desired lime-soil reaction to cause the formation of a hard, dense, impermeable condition of the admixture of lime and soil and one in which a high electrical resistance of said admixture also results.
- the present invention deals with the protection of metal pipes placed underground against corrosive action.
- various fluids such as Water, crude oil, refined petroleum products, natural gas, liquified petroleum gases, slurries and suspensions of solids in liquid or gases in pipelines.
- a most important consideration is the protection of the metal pipe against the corrosive action of the soil in which the pipe or conduit is placed. Since the condition of soil varies a great deal over the many areas in which metal pipe or conduit is buried the problem of corrosion protection is quite complex.
- the pipe may be subject to the effects of electric currents which enhance the difficulties involved in providing full protection against corrosive action.
- the method described herewith is designed to eliminate the use of coatings and/or wrappings of all sorts and cathodic protection of metal pipe or conduit or to further increase the effectiveness of such protective measures, should they be employed in the generally accepted practices related to protecting such buried metal pipe and conduits against corrosive action.
- the method consists of mixing lime with the soil removed during digging of the ditch or trench in which the metal pipe or conduit is to be placed and backfilling the ditch or trench with the admixture.
- the admixture of lime and soil is placed at the bottom of the ditch, the uncoated pipe laid in the ditch, and the ditch filled with the admixture.
- the depth of soil and lime admixture placed in the bottom of the ditch may vary depending on the size of the pipe being laid, though normally with pipe up to 16" diameter, 4" to 6" of the lime-soil admixture is sufiicient. With larger sized pipe the size of the ditch should be such s0 as to provide from 6" to 8" of the lime-soil admixture to encompass the pipe.
- the pipe should have a rather uniform thickness of the soil-lime admixture completely around it. Obviously there may be more than the minimum thicknesses cited above in the upper part of the ditch, depending on the total depth of the trench or ditch.
- the remainder of the trench may be filled with original soil removed from the trench or ditch.
- Tamping, use of mechanical vibrators, or such similar means of causing compression of the admixture may be employed to increase compaction and hasten the consolidation. Slight additions of water may be necessary when the moisture conditions encountered are considered insuflicient. Moisture content for optimum reaction of the lime-soil admixture varies but ranges from 10 to 30 percent have been found to yield good results.
- a sufiicient amount of either hydrated or unhydrated lime is used.
- the quantity of lime required to achieve the desired results varies with the soil and moisture conditions, but it has been 2 percent to 10 percent of lime by weight of soil in most soils.
- a positive reaction is meant a resulting increase in resistivity, a consolidation of the soil-lime mixture, 9. decrease in permeability, an increase in alkalinity (much above that needed for neutralization), and an increased resistance to wetting once drying or partial drying of the soil-lime admixture has taken place.
- the lime-soil reaction which results in a consolidation and hardening of the admixture of lime and soil, may be accelerated through tamping or pressing the admixture around the pipe during backfilling. Though this is the preferred method for placing the lime-soil admixture around the pipe or conduit, it has been found that consolidation takes place without tamping, the natural weight of the back fill being suflicient to yield a Well consolidated hard, impermeable, high electrical and water resistant alkaline material around the pipe or conduit.
- a method of protecting steel pipe or conduit from corrosion when said pipe or conduit is placed underground which employs an admixture of hydrated lime and soil taken from the ditch in which the pipe or conduit is to be buried said admixture containing from 2 to 10 percent of hydrated lime by weight of soil removed from the ditch and further containing from 10 to 25 percent of water by weight of soil removed from the ditch, disposing of said admixture in and around the pipe or conduit by backfilling the ditch with said admixture and compacting the said admixture during the backfilling of the ditch, and completing the compacting when the pipe or conduit has been completely covered thereby obtaining a well consolidated, hard, impermeable, water resistant mass around the pipe or conduit which is alkaline and which exhibits a high electrical resistivity.
- a method of protecting steel pipe or conduit from corrosion when said pipe or conduit is placed underground which employs an admixture of hydrated lime, a naturally occurring or native clay, and soil taken from the ditch in which the pipe or conduit is to be buried, said admixture containing from 2 to 10 percent of hydrated lime by weight of soil removed from the ditch, from 5 to 20 percent of naturally occurring or native clay by weight of soil removed from the ditch, and from 10 to 25 percent of water by weight of soil removed from the ditch, disposing of said admixture in and around the 4 pipe or conduit by backfilling the ditch with such admixture and compacting the said admixture during the back-filling of the ditch, and completing the compacting when the pipe or conduit has been completely covered thereby obtaining a well consolidated, hard, impermeable, water resistant mass around the pipe or conduit which is alkaline and which exhibits a high electrical resistivity.
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Structural Engineering (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Civil Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Description
3,452,952 Patented Aug. 26, 1969 3,462,962 PREVENTIUN F CORRGSMJN 0F METAL PIPES PLACED UNDERGROUND Frank Weldon lessen, 2507 Inwood Place, Austin, Tex. 78703 No Drawing. Filed Oct. 27, 1966, Ser. No. 591,391
Int. Cl. F161 1/00; E02f 5/12; E02d 5/46 US. Cl. 61-72.]; 2 Claims ABSTRACT OF THE DISCLOSURE o be employed to the extent of 5 to 20 percent by weight of the admixture of lime and the original soil if there is insufficient clay in the original soil to yield the desired lime-soil reaction to cause the formation of a hard, dense, impermeable condition of the admixture of lime and soil and one in which a high electrical resistance of said admixture also results.
The present invention deals with the protection of metal pipes placed underground against corrosive action. In all manner of transportation of various fluids such as Water, crude oil, refined petroleum products, natural gas, liquified petroleum gases, slurries and suspensions of solids in liquid or gases in pipelines, a most important consideration is the protection of the metal pipe against the corrosive action of the soil in which the pipe or conduit is placed. Since the condition of soil varies a great deal over the many areas in which metal pipe or conduit is buried the problem of corrosion protection is quite complex. Furthermore the pipe may be subject to the effects of electric currents which enhance the difficulties involved in providing full protection against corrosive action.
The general practice followed in providing corrosion protection when installing or placing metal pipe in the ground is the use of special coatings and wrappings to insulate or separate the pipe from the surrounding soil environment and/or the use of cathodic protection of the metal pipe. Both coating and wrapping and cathodic protection are used in many installations of pipe lines or conduit when severe environmental soil conditions exist. Also, cathodic protection is employed in cases where the metal pipe may not be coated and/ or Wrapped. To repeat, protection of the metal pipe or conduit is sought through the application of coatings and/or wrappings to insulate the metal from the corrosive environment or by use of an applied electric current in the manner provided through cathodic protection methods to minimize or attempt to eliminate completely the corrosion of the metal pipe or conduit which otherwise would take place, or a combination of both.
The method described herewith is designed to eliminate the use of coatings and/or wrappings of all sorts and cathodic protection of metal pipe or conduit or to further increase the effectiveness of such protective measures, should they be employed in the generally accepted practices related to protecting such buried metal pipe and conduits against corrosive action.
Simply, the method consists of mixing lime with the soil removed during digging of the ditch or trench in which the metal pipe or conduit is to be placed and backfilling the ditch or trench with the admixture. The admixture of lime and soil is placed at the bottom of the ditch, the uncoated pipe laid in the ditch, and the ditch filled with the admixture. The depth of soil and lime admixture placed in the bottom of the ditch may vary depending on the size of the pipe being laid, though normally with pipe up to 16" diameter, 4" to 6" of the lime-soil admixture is sufiicient. With larger sized pipe the size of the ditch should be such s0 as to provide from 6" to 8" of the lime-soil admixture to encompass the pipe. That is, the pipe should have a rather uniform thickness of the soil-lime admixture completely around it. Obviously there may be more than the minimum thicknesses cited above in the upper part of the ditch, depending on the total depth of the trench or ditch. After backfilling the ditch or trench with the admixture of lime and soil with an amount suflicient to cover the pipe or conduit with 4" to 8" of said admixture, the remainder of the trench may be filled with original soil removed from the trench or ditch.
Tamping, use of mechanical vibrators, or such similar means of causing compression of the admixture may be employed to increase compaction and hasten the consolidation. Slight additions of water may be necessary when the moisture conditions encountered are considered insuflicient. Moisture content for optimum reaction of the lime-soil admixture varies but ranges from 10 to 30 percent have been found to yield good results.
Of particular importance in the application of the method for the protection of pipes or conduits against corrosion is the use of a sufiicient amount of either hydrated or unhydrated lime. The quantity of lime required to achieve the desired results varies with the soil and moisture conditions, but it has been 2 percent to 10 percent of lime by weight of soil in most soils. By a positive reaction is meant a resulting increase in resistivity, a consolidation of the soil-lime mixture, 9. decrease in permeability, an increase in alkalinity (much above that needed for neutralization), and an increased resistance to wetting once drying or partial drying of the soil-lime admixture has taken place. It has been found that, at times, with soils which are quite sandy or contain large amounts of sand the addition of clay with the lime is necessary to provide a soil-lime admixture which will have the required properties and which will yield satisfactory results for corrosion protection. Thus, the use of a naturally occurring clay, preferably one containing sodium ion as the base exchange cation, can be combined with the. soil and lime to give the desired results. The quantity of clay to be added varies, depending on how sandy the soil may be, and amounts ranging from 5 percent to 20 percent by weight of lime-soil admixture of a native clay can be employed.
The lime-soil reaction, which results in a consolidation and hardening of the admixture of lime and soil, may be accelerated through tamping or pressing the admixture around the pipe during backfilling. Though this is the preferred method for placing the lime-soil admixture around the pipe or conduit, it has been found that consolidation takes place without tamping, the natural weight of the back fill being suflicient to yield a Well consolidated hard, impermeable, high electrical and water resistant alkaline material around the pipe or conduit.
I claim:
1. A method of protecting steel pipe or conduit from corrosion when said pipe or conduit is placed underground which employs an admixture of hydrated lime and soil taken from the ditch in which the pipe or conduit is to be buried said admixture containing from 2 to 10 percent of hydrated lime by weight of soil removed from the ditch and further containing from 10 to 25 percent of water by weight of soil removed from the ditch, disposing of said admixture in and around the pipe or conduit by backfilling the ditch with said admixture and compacting the said admixture during the backfilling of the ditch, and completing the compacting when the pipe or conduit has been completely covered thereby obtaining a well consolidated, hard, impermeable, water resistant mass around the pipe or conduit which is alkaline and which exhibits a high electrical resistivity.
2. A method of protecting steel pipe or conduit from corrosion when said pipe or conduit is placed underground which employs an admixture of hydrated lime, a naturally occurring or native clay, and soil taken from the ditch in which the pipe or conduit is to be buried, said admixture containing from 2 to 10 percent of hydrated lime by weight of soil removed from the ditch, from 5 to 20 percent of naturally occurring or native clay by weight of soil removed from the ditch, and from 10 to 25 percent of water by weight of soil removed from the ditch, disposing of said admixture in and around the 4 pipe or conduit by backfilling the ditch with such admixture and compacting the said admixture during the back-filling of the ditch, and completing the compacting when the pipe or conduit has been completely covered thereby obtaining a well consolidated, hard, impermeable, water resistant mass around the pipe or conduit which is alkaline and which exhibits a high electrical resistivity.
References Cited UNITED STATES PATENTS 2,007,969 7/1935 Grodsky 6172.1 2,065,512 12/1936 Cannon.
2,159,954 5/1939 Powell 61-36 2,558,159 6/1951 Sanick 61-36 X 2,698,252 12/1954 I-Iavelin 94-25 X 3,192,720 7/1965 Schaschl et a1 6136 X 3,243,962 4/1966 Ratliff 61-36 EARL J. WITMER, Primary Examiner
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US59139166A | 1966-10-27 | 1966-10-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3462962A true US3462962A (en) | 1969-08-26 |
Family
ID=24366311
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US591391A Expired - Lifetime US3462962A (en) | 1966-10-27 | 1966-10-27 | Prevention of corrosion of metal pipes placed underground |
Country Status (1)
Country | Link |
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US (1) | US3462962A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4063429A (en) * | 1973-11-07 | 1977-12-20 | Wilson Ernest I | Pipeline retard, support and protection method |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2007969A (en) * | 1933-10-14 | 1935-07-16 | Vladimir A Grodsky | Method of protecting underground pipes and conduits |
US2065512A (en) * | 1934-10-17 | 1936-12-29 | Standard Oil Dev Co | Plugging water sands by a hydratable material |
US2159954A (en) * | 1937-04-13 | 1939-05-23 | Ben F Powell | Method for prevention of seepage of water |
US2558159A (en) * | 1948-05-08 | 1951-06-26 | Sanick Ivar Harry | Lowering the electrical resistance of soils and of electrode-to-soil contacts |
US2698252A (en) * | 1951-08-18 | 1954-12-28 | Jules E Havelin | Lime-fly ash compositions for stabilizing finely divided materials such as soils |
US3192720A (en) * | 1961-06-05 | 1965-07-06 | Pure Oil Co | Anticorrosive back-fill method |
US3243962A (en) * | 1961-04-17 | 1966-04-05 | George R Ratliff | Method and apparatus for treating soil |
-
1966
- 1966-10-27 US US591391A patent/US3462962A/en not_active Expired - Lifetime
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2007969A (en) * | 1933-10-14 | 1935-07-16 | Vladimir A Grodsky | Method of protecting underground pipes and conduits |
US2065512A (en) * | 1934-10-17 | 1936-12-29 | Standard Oil Dev Co | Plugging water sands by a hydratable material |
US2159954A (en) * | 1937-04-13 | 1939-05-23 | Ben F Powell | Method for prevention of seepage of water |
US2558159A (en) * | 1948-05-08 | 1951-06-26 | Sanick Ivar Harry | Lowering the electrical resistance of soils and of electrode-to-soil contacts |
US2698252A (en) * | 1951-08-18 | 1954-12-28 | Jules E Havelin | Lime-fly ash compositions for stabilizing finely divided materials such as soils |
US3243962A (en) * | 1961-04-17 | 1966-04-05 | George R Ratliff | Method and apparatus for treating soil |
US3192720A (en) * | 1961-06-05 | 1965-07-06 | Pure Oil Co | Anticorrosive back-fill method |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4063429A (en) * | 1973-11-07 | 1977-12-20 | Wilson Ernest I | Pipeline retard, support and protection method |
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