CA2068340C - Storage tank having secondary containment - Google Patents
Storage tank having secondary containmentInfo
- Publication number
- CA2068340C CA2068340C CA002068340A CA2068340A CA2068340C CA 2068340 C CA2068340 C CA 2068340C CA 002068340 A CA002068340 A CA 002068340A CA 2068340 A CA2068340 A CA 2068340A CA 2068340 C CA2068340 C CA 2068340C
- Authority
- CA
- Canada
- Prior art keywords
- tank
- storage tank
- inner liner
- rigid
- wall
- 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
- 238000003860 storage Methods 0.000 title claims abstract description 23
- 239000011152 fibreglass Substances 0.000 claims description 7
- 229920001903 high density polyethylene Polymers 0.000 claims description 5
- 239000004700 high-density polyethylene Substances 0.000 claims description 5
- 239000010935 stainless steel Substances 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 239000011148 porous material Substances 0.000 claims 4
- 239000007769 metal material Substances 0.000 claims 2
- 239000011521 glass Substances 0.000 description 8
- 239000000446 fuel Substances 0.000 description 6
- 239000003365 glass fiber Substances 0.000 description 6
- 239000011347 resin Substances 0.000 description 6
- 229920005989 resin Polymers 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 229910000975 Carbon steel Inorganic materials 0.000 description 4
- 239000010962 carbon steel Substances 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 239000011162 core material Substances 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- 229920006305 unsaturated polyester Polymers 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- 239000000945 filler Substances 0.000 description 3
- 238000009787 hand lay-up Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 230000035699 permeability Effects 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 229920002799 BoPET Polymers 0.000 description 2
- 239000004412 Bulk moulding compound Substances 0.000 description 2
- 239000005041 Mylar™ Substances 0.000 description 2
- 239000003677 Sheet moulding compound Substances 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 150000008064 anhydrides Chemical class 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 150000001991 dicarboxylic acids Chemical class 0.000 description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N ethylene glycol Natural products OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000002787 reinforcement Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 240000000491 Corchorus aestuans Species 0.000 description 1
- 235000011777 Corchorus aestuans Nutrition 0.000 description 1
- 235000010862 Corchorus capsularis Nutrition 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229920005830 Polyurethane Foam Polymers 0.000 description 1
- 241000221535 Pucciniales Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- -1 aliphatic mono- Chemical class 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 239000000872 buffer Substances 0.000 description 1
- CREMABGTGYGIQB-UHFFFAOYSA-N carbon carbon Chemical compound C.C CREMABGTGYGIQB-UHFFFAOYSA-N 0.000 description 1
- 239000011203 carbon fibre reinforced carbon Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000000805 composite resin Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 150000002334 glycols Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 239000011496 polyurethane foam Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000000344 soap Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
Classifications
-
- 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
- B65D90/028—Wall construction hollow-walled, e.g. double-walled with spacers
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
- Laminated Bodies (AREA)
Abstract
An underground storage tank having secondary containment comprising a self-supporting, semi-rigid thin liner (40) located on the inside of the tank (25). The thin inner liner (40) completely lines the inside of the tank and is structurally independent of the tank.
Description
WO 92/06gO5 2 0 6 8 3 4 0 PCI/US91/0708~
STORAGE ~AlIK HAVI~G SECONDARY CON~CAINMENT
TECHNICAL FIELD
This invention generally relates to storage tanks and more particularly to underground storage tanks with secondary containment.
BACKGROUND ART
Environmental protection is becoming increasingly important. As our understanding of cont~ tion of soil and water beneath the surface grows, our efforts to prevent leaks increases. Early efforts resulted in glass fiber reinforced plastic single wall underground tanks. See U.S. Patent No.
3,661,294 issued in 1972. As our awareness grew, our efforts to protect the environment matured into glass fiber reinforced plastic double-wall undeLyLoulld tanks, often equipped with leak detection systems. See U.S.
Patent No. 4,561,292 issued in 1985.
Others have attempted to encase or fit rigid storage tanks with secondary containment systems, often with flexible bladders or jackets. See U.S. Patent No.
4,524,609 issued in 1985. Flexible bladders have obvious problems. For example, flexible inner bladders or flexible outer jackets are very susceptible to damage from cutting, tearing, puncturing, etc.
DISCLOSURE OF THE INvnNllON
Basically, my invention is a standard single wall tank (SWT) on the inside of which I have added an FRP smooth inner wall that is not attached to the outer wall. The annular space between the inner and outer wall may have a non-structural porous core such as a thin HDPE
fluid transmitting net.
WO 92/06905 ~ a;~ PCI~/US91/07085 20~8340 The novelty of my invention is a self-supporting, semi-rigid, thin liner inside the SWT. The inner wall can be a thin FRP liner, thin stainless steel or an equivalent material. As I will show, carbon steel liners and flexible bladders do not compare with my discovery.
The thin liner I employ is self-supporting.
Flexible bladders on the other hand require either internal supports or the application of a vacuum between the inner bladder and the outer tank.
This tank has many advantages. One is that the installer can field test the outer wall for leaks prior to installation. Jacketed tanks cannot be field soap tested. Also, in the event of a breach to the primary tank, the FRP outer wall will permeate only negligible amounts of fuel into the environment, as opposed to a jacket which, because of its low resistance to fuel permeation, could allow a significant fuel spill prior to detection.
The thin liner I use has low permeability.
This is important in that some leak sensors that are located between the 2 walls will false alarm if the rate of permeation is too great. This is particularly a challenge for any material that must contain alcohol or blends of fuel containing alcohol.
The thin liners I use have provided corrosion resistance for the internal wall of primary tanks.
Carbon steel often rusts due to water condensate at the bottom of the tank. This has been traditionally overcome by using thick steel (at least 1/4"). This is why thin carbon steel will not work i.e., an allowance for corrosion must be incorporated into carbon steel tanks.
WO 92/0690~ & Q O Pcr/ usg 1/0708S
, . . .
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is more fully explained with reference to the a~comp~nying drawing in which:
Figure 1 is an elevational view of a single wall tank containing an FRP liner in accordance with the present invention.
Figure 2 is a sectional view taken generally along the line 2-2 of Figure 1; and Figure 3 is a fragmentary perspective of an FRP
inner wall panel in accordance with this invention.
BEST MODE OF CARRYING OUT INVENTION
Figure 1 shows a tank 20 which employs the FRP
inner wall structure of the present invention (not shown). The tank 20 is made up of opposed frusto-conical tank halves 22, connected together by center joint 24.
Wall 26 includes a wall element 25 in combination with a rib 28. Actually, a plurality of ribs 28 are axially spaced along the length of the tank 20. Ribs 28 extend peripherally of the tank 20 and act in the nature of strong hoops against radially inwardly crushing forces.
Since they are of high tensile strength, they also absorb tensile stresses to which the tank 20 may be subjected.
It is important to note that the ribs 28 add to the stiffness of the wall 25; also, they provide protective buffers during handling.
The ribs 28 are spaced apart a sufficient distance so that fill and vent fittings 30 and 32 can be installed between the ribs. Optional positions 34 for fittings are thus provided all along the length of the tank 20. In an actual 6,000-gallon capacity tank of 8 feet nominal diameter, and approximately 20 feet length, a spacing of 16 1/2 inches between rib enters was W092/~ ~5 ~ 2 0~ 8 3 ~ O PCT/US91/0708~
employed and this provided adequate space for the installation of the fittings 30 and 32.
U.S. Patent No. 3,661,394 fully describes ribbed, single wall tank construction.
Figure 2 shows FRP inner wall 40 on the inside of wall element 25. Figure 2 also shows annular space 43 between wall 40 and wall element 25. Space 43 is partially filled with porous core 44.
Figure 3 shows a panel of FRP inner wall 40 detached from tank 20.
Typically, one can use any molding process or spray up equipment to make FRP inner wall 40. One can achieve this by placing mold release (Mylar) on a conventional SWT mold, spraying up thin FRP inner liner 40 including end cap, curing the FRP, placing another sheet of Mylar on top of liner 40 and then carrying out the conventional construction of SWT, for example, as described in U.S. Patent No. 3,661,394.
FRP inner wall 40 preferably is made of unsaturated polyester compounds. The practice of this invention, however, is not restricted to unsaturated polyesters.
These compositions, intended to polymerize when molded under heat and pressure, are generally combined with fillers and chopped glass, to produce products having appearance surfaces with a r;n;rllr of irregularities.
The use of chopped glass as reinforcement in such molding compounds is well known. The chopped glass is produced in the form of individual strands which are sized, gathered into rovings, chopped to the desired length and incorporated into the resin composite prior to molding.
WO92/~K PCT/US91/07085 20~834~
The sizes generally comprise a lubricant, film formers and the like and are extremely important in imparting to the reinforcing glass its ability to be wetted out by the molding compound. These sizes are also important in that they protect the glass in it handling subsequent to being sized and are influential in ~;n;m; zing the amount of fuzz and fly which is produced on the glass, the fuzz and fly having a decided affect upon the appearance surface of the molded product.
The sized glass fibers generally are employed as reinforcement for sheet molding compounds (SMC) and bulk molding compounds (BMC).
Unsaturated polyesters useful in this invention typically contain a polyesterification product of one or more ethylenically unsaturated dicarboxylic acids or anhydrides such as maleic or fumaric with one or more glycols such as ethylene or propylene glycol and, sometimes, minor proportions of other aromatic or aliphatic mono- or dicarboxylic acids or anhydrides and/or other mono- or polyhydroxyl compounds. They also typically contain an ethylenically unsaturated monomer, such as styrene, copolymerizable with the unsaturated polyester for curing.
The glass fibers preferably are "E" glass fibers, well known to those skilled in the art. See U.S.
Patent No. 2,334,961.
As I stated above, porous core material 44 may fill space 43. Examples of porous core materials 44, are mattings, nets, screens, and meshes. Specific examples are high density polyethylene (HDPE) net, jute, polyurethane foam, polyester foam, fiberglass matting, cotton matting, nylon matting and corrugated cardboard.
W092/06~5 PCT/US91/07085 2d~8i34Q
l~vu~lKIAL APPLICABILITY
The following table summarizes the advantages of my invention over other alternatives:
TAB~B
THIN WALL FRP INNER TANKS VS OTHER ALTERNATIVES
INVENTION CONTROL
THIN STAINLESS CARBON CARBON FLEXIBLE
UALL 1/10" 1/4" 1/10" BLADDER
Self-Supporting Yes Yes Yes Yes No Low Permeability Yes Yes Yes Yes No to Fuels Internal ~aLl of Primary Yes Yes No No No contairlment Corrosion-Resistant to Alcohol Blend, Fuels, Uster External ~all of Primary Yes Yes No Uo Yes Contairlment Corrosion Resistant to ~ater ll)~lelJell-lellt (ullL.ull~ L~i) Yes Yes Yes Yes Yes From Outer ~all Able to Deter~ine the Yes Yes Yes Yes No location of leaks An alternative embodiment comprises FRP inner wall 40 sections small enough to fit inside a tank through manway openings. Typically the panels are up to 8 feet in length and range from 2 to 4 feet in width.
After the panels are in place inside the tank, one uses a hand lay-up procedure on the seams of each panel to form FRP inner wall 40.
Basically, the procedure involves building up a combination of chopped glass fibers and a hardenable liquid resin and, if desired, a sand filler.
WO 92/06~5 2 0 6 83 ~ ~ PCT/US91/07085 r~
Complete wetting of the chopped glass fibers is desirable and can be accomplished, as is well known in the art, by rolling out the resin and glass and sand mixture. After the seams are fabricated, heat or the passage of time cures the resin. One can use any spray device or combination of spray devices to apply the resin and chopped glass fibers. Often the resin contains an accelerator or catalyst to speed up the curing process.
As shown in Figure 3, the panels and FRP inner liner 40 preferably have the same curvature as wall element 25. Preferably inner FRP liner 40 is thin and typically is 1/8 to 1/4 of an inch thick.
Access to the inside of the tank 20 is provided by a flanged manway fitting 54 (Figure 1) communicating with the inside thereof, and a double-flanged extension 55 normally covered by a cover 56. Hand lay-up secures manway fitting 54 to tank 20 by application of hardenable resin, chopped glass strand and filler such as sand. The hand lay-up procedure is much the same as that used to connect the panels of FRP inner wall 40.
The thin FRP inner liner that I use is unique in that it is:
* Self Supporting * Corrosion resistant * Offers lower permeability In one embodiment, the thin inner liner is structurally independent of the tank for the entire circumference except for a narrow width centered at the top of the bank. For these narrow widths, the inner liner is bonded to the rigid primary tank, thus allowing easy manufacture and installation of tank accessories such as fittings and manways. Alternately, the inner liner can end near the ~A~ . F~ ~
, ;, ~
W092/06905 : .:= PCT/US91/07085 2Q6~3k~
top of the tank resulting in only one wall at the top of the tank. r
STORAGE ~AlIK HAVI~G SECONDARY CON~CAINMENT
TECHNICAL FIELD
This invention generally relates to storage tanks and more particularly to underground storage tanks with secondary containment.
BACKGROUND ART
Environmental protection is becoming increasingly important. As our understanding of cont~ tion of soil and water beneath the surface grows, our efforts to prevent leaks increases. Early efforts resulted in glass fiber reinforced plastic single wall underground tanks. See U.S. Patent No.
3,661,294 issued in 1972. As our awareness grew, our efforts to protect the environment matured into glass fiber reinforced plastic double-wall undeLyLoulld tanks, often equipped with leak detection systems. See U.S.
Patent No. 4,561,292 issued in 1985.
Others have attempted to encase or fit rigid storage tanks with secondary containment systems, often with flexible bladders or jackets. See U.S. Patent No.
4,524,609 issued in 1985. Flexible bladders have obvious problems. For example, flexible inner bladders or flexible outer jackets are very susceptible to damage from cutting, tearing, puncturing, etc.
DISCLOSURE OF THE INvnNllON
Basically, my invention is a standard single wall tank (SWT) on the inside of which I have added an FRP smooth inner wall that is not attached to the outer wall. The annular space between the inner and outer wall may have a non-structural porous core such as a thin HDPE
fluid transmitting net.
WO 92/06905 ~ a;~ PCI~/US91/07085 20~8340 The novelty of my invention is a self-supporting, semi-rigid, thin liner inside the SWT. The inner wall can be a thin FRP liner, thin stainless steel or an equivalent material. As I will show, carbon steel liners and flexible bladders do not compare with my discovery.
The thin liner I employ is self-supporting.
Flexible bladders on the other hand require either internal supports or the application of a vacuum between the inner bladder and the outer tank.
This tank has many advantages. One is that the installer can field test the outer wall for leaks prior to installation. Jacketed tanks cannot be field soap tested. Also, in the event of a breach to the primary tank, the FRP outer wall will permeate only negligible amounts of fuel into the environment, as opposed to a jacket which, because of its low resistance to fuel permeation, could allow a significant fuel spill prior to detection.
The thin liner I use has low permeability.
This is important in that some leak sensors that are located between the 2 walls will false alarm if the rate of permeation is too great. This is particularly a challenge for any material that must contain alcohol or blends of fuel containing alcohol.
The thin liners I use have provided corrosion resistance for the internal wall of primary tanks.
Carbon steel often rusts due to water condensate at the bottom of the tank. This has been traditionally overcome by using thick steel (at least 1/4"). This is why thin carbon steel will not work i.e., an allowance for corrosion must be incorporated into carbon steel tanks.
WO 92/0690~ & Q O Pcr/ usg 1/0708S
, . . .
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is more fully explained with reference to the a~comp~nying drawing in which:
Figure 1 is an elevational view of a single wall tank containing an FRP liner in accordance with the present invention.
Figure 2 is a sectional view taken generally along the line 2-2 of Figure 1; and Figure 3 is a fragmentary perspective of an FRP
inner wall panel in accordance with this invention.
BEST MODE OF CARRYING OUT INVENTION
Figure 1 shows a tank 20 which employs the FRP
inner wall structure of the present invention (not shown). The tank 20 is made up of opposed frusto-conical tank halves 22, connected together by center joint 24.
Wall 26 includes a wall element 25 in combination with a rib 28. Actually, a plurality of ribs 28 are axially spaced along the length of the tank 20. Ribs 28 extend peripherally of the tank 20 and act in the nature of strong hoops against radially inwardly crushing forces.
Since they are of high tensile strength, they also absorb tensile stresses to which the tank 20 may be subjected.
It is important to note that the ribs 28 add to the stiffness of the wall 25; also, they provide protective buffers during handling.
The ribs 28 are spaced apart a sufficient distance so that fill and vent fittings 30 and 32 can be installed between the ribs. Optional positions 34 for fittings are thus provided all along the length of the tank 20. In an actual 6,000-gallon capacity tank of 8 feet nominal diameter, and approximately 20 feet length, a spacing of 16 1/2 inches between rib enters was W092/~ ~5 ~ 2 0~ 8 3 ~ O PCT/US91/0708~
employed and this provided adequate space for the installation of the fittings 30 and 32.
U.S. Patent No. 3,661,394 fully describes ribbed, single wall tank construction.
Figure 2 shows FRP inner wall 40 on the inside of wall element 25. Figure 2 also shows annular space 43 between wall 40 and wall element 25. Space 43 is partially filled with porous core 44.
Figure 3 shows a panel of FRP inner wall 40 detached from tank 20.
Typically, one can use any molding process or spray up equipment to make FRP inner wall 40. One can achieve this by placing mold release (Mylar) on a conventional SWT mold, spraying up thin FRP inner liner 40 including end cap, curing the FRP, placing another sheet of Mylar on top of liner 40 and then carrying out the conventional construction of SWT, for example, as described in U.S. Patent No. 3,661,394.
FRP inner wall 40 preferably is made of unsaturated polyester compounds. The practice of this invention, however, is not restricted to unsaturated polyesters.
These compositions, intended to polymerize when molded under heat and pressure, are generally combined with fillers and chopped glass, to produce products having appearance surfaces with a r;n;rllr of irregularities.
The use of chopped glass as reinforcement in such molding compounds is well known. The chopped glass is produced in the form of individual strands which are sized, gathered into rovings, chopped to the desired length and incorporated into the resin composite prior to molding.
WO92/~K PCT/US91/07085 20~834~
The sizes generally comprise a lubricant, film formers and the like and are extremely important in imparting to the reinforcing glass its ability to be wetted out by the molding compound. These sizes are also important in that they protect the glass in it handling subsequent to being sized and are influential in ~;n;m; zing the amount of fuzz and fly which is produced on the glass, the fuzz and fly having a decided affect upon the appearance surface of the molded product.
The sized glass fibers generally are employed as reinforcement for sheet molding compounds (SMC) and bulk molding compounds (BMC).
Unsaturated polyesters useful in this invention typically contain a polyesterification product of one or more ethylenically unsaturated dicarboxylic acids or anhydrides such as maleic or fumaric with one or more glycols such as ethylene or propylene glycol and, sometimes, minor proportions of other aromatic or aliphatic mono- or dicarboxylic acids or anhydrides and/or other mono- or polyhydroxyl compounds. They also typically contain an ethylenically unsaturated monomer, such as styrene, copolymerizable with the unsaturated polyester for curing.
The glass fibers preferably are "E" glass fibers, well known to those skilled in the art. See U.S.
Patent No. 2,334,961.
As I stated above, porous core material 44 may fill space 43. Examples of porous core materials 44, are mattings, nets, screens, and meshes. Specific examples are high density polyethylene (HDPE) net, jute, polyurethane foam, polyester foam, fiberglass matting, cotton matting, nylon matting and corrugated cardboard.
W092/06~5 PCT/US91/07085 2d~8i34Q
l~vu~lKIAL APPLICABILITY
The following table summarizes the advantages of my invention over other alternatives:
TAB~B
THIN WALL FRP INNER TANKS VS OTHER ALTERNATIVES
INVENTION CONTROL
THIN STAINLESS CARBON CARBON FLEXIBLE
UALL 1/10" 1/4" 1/10" BLADDER
Self-Supporting Yes Yes Yes Yes No Low Permeability Yes Yes Yes Yes No to Fuels Internal ~aLl of Primary Yes Yes No No No contairlment Corrosion-Resistant to Alcohol Blend, Fuels, Uster External ~all of Primary Yes Yes No Uo Yes Contairlment Corrosion Resistant to ~ater ll)~lelJell-lellt (ullL.ull~ L~i) Yes Yes Yes Yes Yes From Outer ~all Able to Deter~ine the Yes Yes Yes Yes No location of leaks An alternative embodiment comprises FRP inner wall 40 sections small enough to fit inside a tank through manway openings. Typically the panels are up to 8 feet in length and range from 2 to 4 feet in width.
After the panels are in place inside the tank, one uses a hand lay-up procedure on the seams of each panel to form FRP inner wall 40.
Basically, the procedure involves building up a combination of chopped glass fibers and a hardenable liquid resin and, if desired, a sand filler.
WO 92/06~5 2 0 6 83 ~ ~ PCT/US91/07085 r~
Complete wetting of the chopped glass fibers is desirable and can be accomplished, as is well known in the art, by rolling out the resin and glass and sand mixture. After the seams are fabricated, heat or the passage of time cures the resin. One can use any spray device or combination of spray devices to apply the resin and chopped glass fibers. Often the resin contains an accelerator or catalyst to speed up the curing process.
As shown in Figure 3, the panels and FRP inner liner 40 preferably have the same curvature as wall element 25. Preferably inner FRP liner 40 is thin and typically is 1/8 to 1/4 of an inch thick.
Access to the inside of the tank 20 is provided by a flanged manway fitting 54 (Figure 1) communicating with the inside thereof, and a double-flanged extension 55 normally covered by a cover 56. Hand lay-up secures manway fitting 54 to tank 20 by application of hardenable resin, chopped glass strand and filler such as sand. The hand lay-up procedure is much the same as that used to connect the panels of FRP inner wall 40.
The thin FRP inner liner that I use is unique in that it is:
* Self Supporting * Corrosion resistant * Offers lower permeability In one embodiment, the thin inner liner is structurally independent of the tank for the entire circumference except for a narrow width centered at the top of the bank. For these narrow widths, the inner liner is bonded to the rigid primary tank, thus allowing easy manufacture and installation of tank accessories such as fittings and manways. Alternately, the inner liner can end near the ~A~ . F~ ~
, ;, ~
W092/06905 : .:= PCT/US91/07085 2Q6~3k~
top of the tank resulting in only one wall at the top of the tank. r
Claims (17)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An underground storage tank comprising:
a rigid tank particularly suited for use underground; and, an inner liner located on the inside of the rigid tank, the inner liner having sufficient flexibility so that it would substantially collapse if totally unconstrained by the rigid tank, but having sufficient rigidity so that it would substantially conform to the shape of the rigid tank when positioned within the rigid tank.
a rigid tank particularly suited for use underground; and, an inner liner located on the inside of the rigid tank, the inner liner having sufficient flexibility so that it would substantially collapse if totally unconstrained by the rigid tank, but having sufficient rigidity so that it would substantially conform to the shape of the rigid tank when positioned within the rigid tank.
2. The storage tank of claim 1, wherein the inner liner is structurally independent of the rigid tank.
3. The storage tank of claim 2, wherein an annular space exists between the rigid tank and inner liner.
4. The storage tank of claim 3, including gas porous material in the annular space between the rigid tank and inner liner.
5. The storage tank of claim 4, wherein the gas porous material is a high-density polyethylene net.
6. The storage tank of claim 3, wherein the inner liner is glass fiber reinforced plastic.
7. The storage tank of claim 2, wherein the inner liner is glass fiber reinforced plastic from 0.020"
to 0.250" thick.
to 0.250" thick.
8. The storage tank of claim 2, wherein the inner liner is stainless steel or other metallic material from 0.010" to 0.125" thick.
9. The storage tank of claim 1, wherein the inner liner would collapse by at least about 90 percent of its manufactured diameter if totally unconstrained, but would remain at a height of at least about 95 percent of its manufactured diameter when positioned within the rigid tank.
10. The storage tank of claim 9, wherein the inner liner is structurally independent of the rigid tank.
11. The storage tank of claim 10, wherein the inner liner would collapse by at least about 25 percent of its manufactured diameter if totally unconstrained, but would remain at a height of at least about 98 percent of its manufactured diameter when positioned within the rigid tank.
12. The storage tank of claim 10, wherein an annular space exists between the rigid tank and inner liner.
13. The storage tank of claim 12, including gas porous material in the annular space between the tank and inner liner.
14. The storage tank of claim 13, wherein the gas porous material is a high-density polyethylene net.
15. The storage tank of claim 10, wherein the inner liner is glass fiber reinforced plastic.
16. The storage tank of claim 10, wherein the inner liner is glass fiber reinforced plastic from 0.020"
to 0.250" thick.
to 0.250" thick.
17. The storage tank of claim 10, wherein the inner liner is stainless steel or other metallic material from 0.010" to 0.125" thick.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US59618990A | 1990-10-12 | 1990-10-12 | |
| US596,189 | 1990-10-12 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2068340A1 CA2068340A1 (en) | 1992-04-13 |
| CA2068340C true CA2068340C (en) | 1996-05-21 |
Family
ID=24386314
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002068340A Expired - Lifetime CA2068340C (en) | 1990-10-12 | 1991-09-30 | Storage tank having secondary containment |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0505534A1 (en) |
| JP (1) | JPH05505375A (en) |
| AU (1) | AU651997B2 (en) |
| CA (1) | CA2068340C (en) |
| NZ (1) | NZ240909A (en) |
| WO (1) | WO1992006905A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2003903578A0 (en) * | 2003-07-11 | 2003-07-24 | Bluescope Steel Limited | Improved water tank and method of making same |
| CN103523404A (en) * | 2013-09-29 | 2014-01-22 | 江苏中储能源装备有限公司 | High-temperature storage tank body structure |
| RU186800U1 (en) * | 2018-11-06 | 2019-02-04 | Александр Александрович Сапожников | LIGHTED RESERVOIR TANK FOR STORAGE OF OIL PRODUCTS |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1942728A1 (en) * | 1969-08-22 | 1971-03-04 | Stefan Nau Fa | Plastics storage container |
| DE2046771A1 (en) * | 1970-09-23 | 1972-03-30 | Höger, Johann, 8440 Straubing | Wandungselemennt for liquid containers |
| CH551859A (en) * | 1973-06-05 | 1974-07-31 | Raess Paul | PROCESS FOR MANUFACTURING A SPHAEROID, DOUBLE-WALLED LARGE CONTAINER MADE FROM GLASS FIBER REINFORCED PLASTIC LAMINATE. |
| DE3147452A1 (en) * | 1981-12-01 | 1983-07-28 | Ceilcote Korrosionstechnik GmbH, 6081 Biebesheim | CONTAINER WITH A LINING |
| WO1986007574A1 (en) * | 1985-06-17 | 1986-12-31 | Sharp Bruce R | Storage tanks having formed jacket for secondary containment |
| AU597638B2 (en) * | 1986-04-15 | 1990-06-07 | Arthur George Yarrington | Kit water storage tank or silo |
| DE3841463A1 (en) * | 1988-01-11 | 1989-07-20 | Walter Ludwig Behaelter Stahl | Liquid container |
-
1991
- 1991-09-30 CA CA002068340A patent/CA2068340C/en not_active Expired - Lifetime
- 1991-09-30 JP JP91516186A patent/JPH05505375A/en active Pending
- 1991-09-30 AU AU85490/91A patent/AU651997B2/en not_active Expired - Fee Related
- 1991-09-30 WO PCT/US1991/007085 patent/WO1992006905A1/en not_active Ceased
- 1991-09-30 EP EP91917134A patent/EP0505534A1/en not_active Withdrawn
- 1991-12-09 NZ NZ240909A patent/NZ240909A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| WO1992006905A1 (en) | 1992-04-30 |
| AU651997B2 (en) | 1994-08-11 |
| NZ240909A (en) | 1993-11-25 |
| CA2068340A1 (en) | 1992-04-13 |
| EP0505534A1 (en) | 1992-09-30 |
| JPH05505375A (en) | 1993-08-12 |
| AU8549091A (en) | 1992-05-20 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |