EP0122980A2 - Protective internal coating for restoring underground metal tanks and process for its application - Google Patents
Protective internal coating for restoring underground metal tanks and process for its application Download PDFInfo
- Publication number
- EP0122980A2 EP0122980A2 EP83201830A EP83201830A EP0122980A2 EP 0122980 A2 EP0122980 A2 EP 0122980A2 EP 83201830 A EP83201830 A EP 83201830A EP 83201830 A EP83201830 A EP 83201830A EP 0122980 A2 EP0122980 A2 EP 0122980A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- epoxy resin
- paint
- applying
- internal coating
- layer
- 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.)
- Withdrawn
Links
- 238000000576 coating method Methods 0.000 title claims abstract description 21
- 239000011248 coating agent Substances 0.000 title claims abstract description 20
- 239000002184 metal Substances 0.000 title claims abstract description 11
- 230000001681 protective effect Effects 0.000 title claims abstract 8
- 238000000034 method Methods 0.000 title claims description 9
- 239000003973 paint Substances 0.000 claims abstract description 21
- 239000004744 fabric Substances 0.000 claims abstract description 20
- 239000011152 fibreglass Substances 0.000 claims abstract description 16
- 239000003822 epoxy resin Substances 0.000 claims abstract description 15
- 229920000647 polyepoxide Polymers 0.000 claims abstract description 15
- 229920000642 polymer Polymers 0.000 claims abstract 2
- 239000004593 Epoxy Substances 0.000 claims description 13
- 238000011065 in-situ storage Methods 0.000 claims description 5
- 238000004140 cleaning Methods 0.000 claims description 2
- 238000005554 pickling Methods 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims 1
- 239000000126 substance Substances 0.000 abstract description 10
- 239000003795 chemical substances by application Substances 0.000 abstract description 2
- 239000011253 protective coating Substances 0.000 description 7
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000000446 fuel Substances 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 239000003651 drinking water Substances 0.000 description 1
- 235000020188 drinking water Nutrition 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004848 polyfunctional curative Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000003900 soil pollution Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/50—Multilayers
- B05D7/56—Three layers or more
- B05D7/57—Three layers or more the last layer being a clear coat
- B05D7/574—Three layers or more the last layer being a clear coat at least some layers being let to dry at least partially before applying the next layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/22—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes
- B05D7/227—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes of containers, cans or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D90/00—Component parts, details or accessories for large containers
- B65D90/02—Wall construction
- B65D90/022—Laminated structures
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2504/00—Epoxy polymers
Definitions
- the present invention relates to restoration or repair of underground metal tanks or reservoirs which were damaged by corrosion, and more particularly, but not exclusively, of tanks for combustible oils.
- the protective coating according to the present invention is applied inside metal tanks undergoing the corrosive action of internal and/or external agents.
- the protective coating for underground tanks according to the present invention does not show the above mentioned drawbacks and it is advantageously used also for drinking water reservoirs, compartments of tankers for crude oil or water transportation (and ballast in the empty no-load trip) and the like.
- the protective coating for underground tanks consists of a plurality of layers of two materials only, and more particularly, but not exclusively, of an epoxy paint and a fiberglass fabric.
- the so obtained coating consisting of said combination of epoxy products and fiberglass fabric and having a thickness of 1500 - 4000 microns, has a very high mechanical strength and cannot be attacked by acids and stray currents.
- the coating consisting of such a combination warrants a good tank tightness even in presence of severe external corrosion.
- the coating according to the present invention may also be formed by a greater number of layers of fiberglass cloth and epoxy resin, in case the conditions of the tank sheet plates require so.
- protective coatings of greater thickness may be not suitable from both the technical and economical paint of view.
- a coating consisting of four layers, namely two layers of epoxy paint, one of fiberglass cloth and a final vitrifying overlay coat.
- the epoxy paint used in the protective coating according to the present invention may be any one of the known paints of this kind, i.e. having a high adhesive power in respect of both the metal and the fiberglass fabric used, a high resistance to the attack of chemicals to the found in the field of use, an expansion compatible with that of metal and it must be miscible with suitable hardeners, whose properties are to be dictated by the field and product of use. It could also be possible to use polymeric fabrics having a high elasticity modulus.
- the coatings according to the present invention consisting of four or more layers, were applied on sheet plate samples and subjected to tests of resistance to stray currents, to aggressive chemicals and of mechanical strength at room temperature.
- the internal coating for underground tanks according to the present invention is prepared in situ and therefore has a simple and quick application, so as to form by itself an alternative structure to the tank.
- the components i.e. paints and fiberglass cloths
- the components may be prepared when required and their preparation requires only common and direct operations.
- Other materials could be considered as components by a man skilled in the art but they would be equivalent as to properties and processing operations, so that their use falls in the scope of the present invention.
- the internal coating for underground is mainly characterized by the combination of two materials such as epoxy resins and fiberglass cloth, to be applied in situ as layers with simple known, methods of the relevant technique.
- Another valuable characteristic of the application in situ of the coating of the present invention is its reliability as to lack of toxicity and development of explosive gases.
- a further valuable characteristic of the application in situ of the coating of the present invention for restoring old underground tanks is the formation of an inner shell having autonomous chemical and mechanical features in respect of those of the tank, and therefore of a structure which is not influenced by the tank conditions.
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Mechanical Engineering (AREA)
- Laminated Bodies (AREA)
Abstract
Description
- The present invention relates to restoration or repair of underground metal tanks or reservoirs which were damaged by corrosion, and more particularly, but not exclusively, of tanks for combustible oils.
- The protective coating according to the present invention is applied inside metal tanks undergoing the corrosive action of internal and/or external agents.
- It is well known that the inner surface of a metal tank, used to contain combustible oils, undergoes the direct action of the various substances which are refining residues, said action being enhanced by condensate water normally formed in said tanks in summertime.
- It is also known that the outer surface of the tank undergoes an intense action by stray currents and chemicals contained in the soil. The aggressivity of these chemicals is also considerably increased with time as for instance rain removes from atmosphere big amounts of acidic products which penetrate into the ground and then come in contact with the outer surface of said underground tanks.
- Tarring normally used for the external protection of the tank, though of very good quality, is not giving acceptable results against stray currents and undergoes a rapid decay with time.
- The above mentioned corrosive actions began to appear in a very negative way. The occurrences of tanks showing damages due to metal corrosion are more and more frequent. Damaged or perforated tanks are causing loss of large quantities of fuel and consequently soil pollution. The leaking fuel penetrates underground, reaches water beds and spreads everywhere. Such occurrences now begin to awaken fear.
- The most recent techniques for newly installed tanks provide for protective coatings consisting of epoxy products without solvents. One of the decisive factors for a good lifetime of these protective coatings is their thickness. Said techniques provide also for the application to existing underground tanks of bearing coating of sandwiched plastics which gave satisfactory results but are expensive and are subject to considerable difficulties of application.
- The protective coating for underground tanks according to the present invention does not show the above mentioned drawbacks and it is advantageously used also for drinking water reservoirs, compartments of tankers for crude oil or water transportation (and ballast in the empty no-load trip) and the like.
- The protective coating for underground tanks according to the present invention consists of a plurality of layers of two materials only, and more particularly, but not exclusively, of an epoxy paint and a fiberglass fabric.
- The application of said coating is carried out according to a process comprising the following steps:
- (a) internal cleaning of the tank and pickling of the inner sheet plate by one of the known mechanical, thermal or chemical methods;
- (b) thorough cheking of the inner surface to ascertain its strength condition;
- (c) if the sheet plate is still in a good condition, applying a first layer or primer of epoxy paint having the particular characteristic of penetrating into the eventual corrosion areas and holes so as to form a true seal of the holes and strengthening of the plate, said paint having a density between 1.6 and 1.8 of tixotropic viscosity;
- (d) letting the layer stand for about two hours in order to allow optimal setting of the epoxy paint;
- (e) applying fiberglass cloths of any known type, the choice of the epoxy paint and fiberglass being such as to constitute a composite product with an optimal elasticity modulus in respect of the metal of the tank;
- (f) applying a second layer of epoxy paint;
- (g) curing at room temperature the group comprised of epoxy resin + fiberglass cloth + epoxy resin;
- (h) applying a final overlay of vitrifying epoxy paint;
- (i) hardening the whole by means of hot air blow.
- The so obtained coating, consisting of said combination of epoxy products and fiberglass fabric and having a thickness of 1500 - 4000 microns, has a very high mechanical strength and cannot be attacked by acids and stray currents. The coating consisting of such a combination warrants a good tank tightness even in presence of severe external corrosion.
- The coating according to the present invention may also be formed by a greater number of layers of fiberglass cloth and epoxy resin, in case the conditions of the tank sheet plates require so. However, it is clear that protective coatings of greater thickness may be not suitable from both the technical and economical paint of view.
- For these reasons it is presently preferred to use a coating consisting of four layers, namely two layers of epoxy paint, one of fiberglass cloth and a final vitrifying overlay coat.
- The epoxy paint used in the protective coating according to the present invention may be any one of the known paints of this kind, i.e. having a high adhesive power in respect of both the metal and the fiberglass fabric used, a high resistance to the attack of chemicals to the found in the field of use, an expansion compatible with that of metal and it must be miscible with suitable hardeners, whose properties are to be dictated by the field and product of use. It could also be possible to use polymeric fabrics having a high elasticity modulus.
- The coatings according to the present invention, consisting of four or more layers, were applied on sheet plate samples and subjected to tests of resistance to stray currents, to aggressive chemicals and of mechanical strength at room temperature.
- ` The results were totally satisfactory and showed that the combination of epoxy paint and fiberglass fabric increases the properties of the combination in view of the similar and complementary character of the components. The resistance to chemicals is of more than 24 months for almost all aggressive substances, the mechanical strength is from 16 atm. up to 30 atm. and more of pressure of the punch of the INTRON electronic dynamometer according to the test conditions (it is to be pointed out that the actual maximum pressures undergoing an underground tank are of 1 atm inside and 0.5 atm outside) and a sheet plate covered with this coating results to be insulated against currents of high value.
- The internal coating for underground tanks according to the present invention is prepared in situ and therefore has a simple and quick application, so as to form by itself an alternative structure to the tank.
- The components, i.e. paints and fiberglass cloths, may be prepared when required and their preparation requires only common and direct operations. Other materials could be considered as components by a man skilled in the art but they would be equivalent as to properties and processing operations, so that their use falls in the scope of the present invention. The internal coating for underground is mainly characterized by the combination of two materials such as epoxy resins and fiberglass cloth, to be applied in situ as layers with simple known, methods of the relevant technique.
- Another valuable characteristic of the application in situ of the coating of the present invention is its reliability as to lack of toxicity and development of explosive gases.
- A further valuable characteristic of the application in situ of the coating of the present invention for restoring old underground tanks is the formation of an inner shell having autonomous chemical and mechanical features in respect of those of the tank, and therefore of a structure which is not influenced by the tank conditions.
Claims (7)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT20070/83A IT1161916B (en) | 1983-03-15 | 1983-03-15 | METHOD FOR THE RECLAMATION AND RESTORATION OF UNDERGROUND METAL TANKS |
IT2007083 | 1983-03-15 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0122980A2 true EP0122980A2 (en) | 1984-10-31 |
EP0122980A3 EP0122980A3 (en) | 1986-07-16 |
Family
ID=11163562
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP83201830A Withdrawn EP0122980A3 (en) | 1983-03-15 | 1983-12-21 | Protective internal coating for restoring underground metal tanks and process for its application |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0122980A3 (en) |
IT (1) | IT1161916B (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0470321A1 (en) * | 1990-08-09 | 1992-02-12 | Adisa Entwicklungs Ag | Tank and method of manufacturing same |
ES2087822A1 (en) * | 1994-05-20 | 1996-07-16 | Rafibra S L | Process for covering metallic deposits |
ITLU20110003A1 (en) * | 2011-03-01 | 2012-09-02 | Maremmana Ecologia Srl | METAL TANK RENOVATION SYSTEM USED FOR STORAGE OF LIQUID PRODUCTS |
CN113403081A (en) * | 2021-06-17 | 2021-09-17 | 王万斌 | Protection method for unearthed cultural relics |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2286677A1 (en) * | 1974-10-02 | 1976-04-30 | Malningstekniska Ingenjorsbyra | Coating metal (e.g. sheet iron) containers for oil storage - using gfr. polyester or epoxy compsns |
EP0028904A1 (en) * | 1979-11-08 | 1981-05-20 | General Signal Corporation | Multi-layered, fiberglass-reinforced floor covering systems and method of making them |
-
1983
- 1983-03-15 IT IT20070/83A patent/IT1161916B/en active
- 1983-12-21 EP EP83201830A patent/EP0122980A3/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2286677A1 (en) * | 1974-10-02 | 1976-04-30 | Malningstekniska Ingenjorsbyra | Coating metal (e.g. sheet iron) containers for oil storage - using gfr. polyester or epoxy compsns |
EP0028904A1 (en) * | 1979-11-08 | 1981-05-20 | General Signal Corporation | Multi-layered, fiberglass-reinforced floor covering systems and method of making them |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0470321A1 (en) * | 1990-08-09 | 1992-02-12 | Adisa Entwicklungs Ag | Tank and method of manufacturing same |
US5269436A (en) * | 1990-08-09 | 1993-12-14 | Adisa Entwicklungs Ag | Double-wall tank and method of its manufacture |
ES2087822A1 (en) * | 1994-05-20 | 1996-07-16 | Rafibra S L | Process for covering metallic deposits |
ITLU20110003A1 (en) * | 2011-03-01 | 2012-09-02 | Maremmana Ecologia Srl | METAL TANK RENOVATION SYSTEM USED FOR STORAGE OF LIQUID PRODUCTS |
CN113403081A (en) * | 2021-06-17 | 2021-09-17 | 王万斌 | Protection method for unearthed cultural relics |
Also Published As
Publication number | Publication date |
---|---|
EP0122980A3 (en) | 1986-07-16 |
IT8320070A0 (en) | 1983-03-15 |
IT1161916B (en) | 1987-03-18 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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AK | Designated contracting states |
Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
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PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
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AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
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17P | Request for examination filed |
Effective date: 19861211 |
|
17Q | First examination report despatched |
Effective date: 19871023 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 19880303 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: CASASSA, ANDREA |