US3916189A - Low temperature liquid storage tank having crack-detecting means - Google Patents

Low temperature liquid storage tank having crack-detecting means Download PDF

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US3916189A
US3916189A US47914374A US3916189A US 3916189 A US3916189 A US 3916189A US 47914374 A US47914374 A US 47914374A US 3916189 A US3916189 A US 3916189A
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layer
low temperature
temperature liquid
tank
impermeable material
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Kihei Katsuta
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Mitsubishi Heavy Industries Ltd
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Mitsubishi Heavy Industries Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C3/00—Vessels not under pressure
    • F17C3/02—Vessels not under pressure with provision for thermal insulation
    • F17C3/04—Vessels not under pressure with provision for thermal insulation by insulating layers
    • F17C3/06—Vessels not under pressure with provision for thermal insulation by insulating layers on the inner surface, i.e. in contact with the stored fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00—Details of vessels or of the filling or discharging of vessels
    • F17C13/12—Arrangements or mounting of devices for preventing or minimising the effect of explosion ; Other safety measures
    • F17C13/126—Arrangements or mounting of devices for preventing or minimising the effect of explosion ; Other safety measures for large storage containers for liquefied gas
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
    • G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
    • G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
    • G01M3/22—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators
    • G01M3/226—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators for containers, e.g. radiators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2201/00—Vessel construction, in particular geometry, arrangement or size
    • F17C2201/01—Shape
    • F17C2201/0147—Shape complex
    • F17C2201/0157—Polygonal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/03—Thermal insulations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/03—Thermal insulations
    • F17C2203/0304—Thermal insulations by solid means
    • F17C2203/0329—Foam
    • F17C2203/0333—Polyurethane
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0634—Materials for walls or layers thereof
    • F17C2203/0636—Metals
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2203/00—Vessel construction, in particular walls or details thereof
    • F17C2203/06—Materials for walls or layers thereof; Properties or structures of walls or their materials
    • F17C2203/0634—Materials for walls or layers thereof
    • F17C2203/0636—Metals
    • F17C2203/0639—Steels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
    • F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
    • F17C2223/0146—Two-phase
    • F17C2223/0153—Liquefied gas, e.g. LPG, GPL
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2260/00—Purposes of gas storage and gas handling
    • F17C2260/03—Dealing with losses
    • F17C2260/035—Dealing with losses of fluid
    • F17C2260/038—Detecting leaked fluid

Definitions

  • the present invention relates to a low temperature liquid storage tank having crack-detecting means and,
  • the present invention aims at avoiding the difficulties in the prior art low temperature liquid storage tank.
  • the object of the present invention is to provide a novel and useful low temperature liquid storage tank having crack-detecting means in which detection of cracks possibly generated in the impermeable layer of the tank can be easily and exactly effected by the provision of sources of radioactive element on the inner wall of the tank shell.
  • the low temperature liquid storage tank having crack-detecting means in accordance with the present invention comprises at least a heat insulating layer and at least an impermeable layer applied to the inner wall of the tank shell in laminated relationship with each other, the tank being characterized in that a plurality of hermetically sealed sources of radioisotope are secured to the inner surface of the tank shell in spaced relationship from each other.
  • FIG. 1 is a schematic cross-sectional view showing the hull of a ship in which a low temperature liquefied gas storage tank having crack-detecting means in accordance with the present invention is incorporated;
  • FIG. 2 is a fragmentary cross-sectional view in enlarged scale showing in detail a portion of the low temperature liquefied gas storage tank of FIG. 1;
  • FIG. 3 is a diagram showing the results of measurement of the emissivity of radiation given in relation to the conditions shown in FIG. 2;
  • FIG. 4 is a fragmentary cross-sectional view showing in more detail the construction of the source of radioisotope shown in circle A in FIG. 2.
  • a primary impermeable layer 3 made of a low temperature resistant material is provided on the inside of the tank shell 1 forming the hull with the interposition of a heat insulating layer 2 of a material such as foamed resin.
  • Ballast tanks B are provided at both the ships sides and the ships bottom.
  • the space L is used to receive the low temperature liquid for storage thereof.
  • a secondary impermeable layer 4 is shown as being provided in the interior of the heat insulating layer Z'arranged between the tank shell 1 and theinnermost primary impermeable layer 3.
  • a plurality of hermetically sealed sources 5 of radioisotope are secured to the inner surface of the tank shell 1 in spaced relationship from each other.
  • the heat insulating layer 2 is divided into a primary heat insulating layer 2a and a secondary heat insulating layer 2b by the secondary impermeable layer 4.
  • a material having a superior heat insulating property such as hard polyurethane foam, polystyrene foam and polyethylene foam may be employed.
  • an ordinary steel for ship construction may be used which is not noted for having a low temperature resistant property.
  • a composite low temperature resistant material such as a material sold by the Tradename Aluminilar having metallic foils of a high malleability and a low gas permeability such as aluminum foils laminated with polyester resin and a composite material having glass fibers or carbon fibers combined with polyurethane resin, epoxy resin, silicone resin of polytetrafluoroethylene, tetrafloroethylene copolymer must be used.
  • the hermetically sealed source-5 of radioisotope is secured to the inner surface of the tank shell I by means of bonding agent 6 and received in the recess of the second heat insulating layer 2b.
  • a sealed container a made of lead of the source 5 is formed with a window 5b opening toward the interior of the tank.
  • a capsule 5c is housed in the container 5a and a predetermined quantity of radioisotope 5d (cobalt 60, for example) is hermetically housed in the capsule 5c.
  • the inspection of cracks as described above can be effected during the construction of the tank.
  • the crack inspection is to be carried out at the time the secondary impermeable layer 4 has been completed and at the time the primary impermeable layer 3 has been completed.
  • cobalt 60 can be used most easily.
  • the half life of cobalt 60 is 5.2 years, and, assuming that the depreciation period of the ship having the low temperature liquid storage tank described above is years, the quantity of the radioisotope as the source 5 merely decreases to about one-sixteenth, and the quantity of lane of radioisotope suffices for one source.
  • the total quantity of the sources in a ship may be in the order of 1 mac thereby permitting the total quantity of the sources to be limited to the degree capable of sufficiently insuring the security of the ship.
  • Apparatus comprising:
  • the tank is adapted for storing low temperature liquid
  • each source including shielding providing window means oriented toward the inside of the tank, so that cracks in the at least one 4 low temperature liquidimpermeable layer may be detected from within the tank.
  • the hermetically sealed sources of radioisotope are each constituted by a capsule of cobalt 6O encased in lead.
  • the second layer of low temperature liquid-impermeable material functions as the primary layer of low temperature liquid-impermeable material and the first-described layer of low temperature liquidimpermeable material functions as a secondary layer of low temperature liquid-impermeable material.
  • tanker ship for transporting liquefied gas, said ship incorporating said liquid storage tank.
  • said wall means is constituted by steel.
  • the heat insulating material is constituted by rigid foamed plastic resin.
  • the at least one layer of low temperature liquidimpermeable material is constituted by a composite aluminum foil laminated with polyester resin.
  • the at least one layer of low temperature liquidimpermeable material is constituted by a composite of fiber reinforced polyurethane resin.
  • the at least one layer of low temperature liquidimpermeable material is constituted by a composite of fiber-reinforced epoxy resin.
  • the at least one layer of low temperature liquidimpermeable material is constituted by a composite of fiber-reinforced silicone resin.
  • the at least one layer of low temperature liquidimpermeable material is constituted by a composite of fiber-reinforced polytetrafluoroethylene-tetrafluoroethylene copolymer.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)
  • Closures For Containers (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Examining Or Testing Airtightness (AREA)

Abstract

The low temperature liquid storage tank having crack-detecting means of the present invention is provided with at least a heat insulating layer and at least an impermeable layer applied to the inner wall of the tank shell in laminated relationship with each other. A plurality of hermetically sealed sources of radioisotope are secured to the inner surface of the tank shell so that any crack in the impermeable layer, if such is generated, can be detected by detecting leakage of radiation from the sources through such a crack by a dosimeter.

Description

United States Patent Katsuta Oct. 28, 1975 LOW TEMPERATURE LIQUID STORAGE 2,674,695 4/1954 Grace 250/357 TANK HAVING CRACK DETECTING 2,794,953 6/1957 Callender... 250/303 MEANS 3,439,166 4/1969 Chope 250/358 3,531,638 9/1970 Badgett 250/364 [75] Inventor: Kihei Katsuta, Nagasaki, Japan [73] Assignee: Mitsubishi Jukogyo Kabushiki Primary Examiner-mold Dixon Kaisha, Tokyo Japan Attorney, Agent, or FzrmCushman, Darby &
Cushman [22] Filed: June 13, 1974 [21] Appl. No.: 479,143 [57] ABSTRACT The low temperature liquid storage tank having crack- [30] F i Application priority m detecting means of the present invention is provided J 22, 1973 J n 2 with at least a heat insulating layer and at least an imune apan 48 7055 permeable layer applied to the inner wall of the tank [52] Us. CL 250/303 250/364 shell in laminated relationship with each other. A plu- [511 Int. GOIT U161 rality of hermetically sealed sources of radio-isotope [58] Field of l 312 358 are secured to the inner surface of the tank shell so 250/357 that any crack in the impermeable layer, if such is generated, can be detected by detecting leakage of ra- [56] References Cited diation from the sources through such a crack by a do- UNITED STATES PATENTS 2,518,327 8/1950 Jahn 250 303 11 Claims, 4 Drawing Figures U.S. Patent Oct. 28, 1975 Sheet 1 of2 3,916,189
LOW TEMPERATURE LIQUID STORAGE TANK HAVING CRACK-DETECTING MEANS BACKGROUND OF THE INVENTION The present invention relates to a low temperature liquid storage tank having crack-detecting means and,
more particularly, to a low temperature liquid storage of the internal heat insulating type having crack-detecting means wherein at least a heat insulating layer and at least an impermeable layer are laminated on the inner wall of the tank shell.
Heretofore, in a low temperature liquid storage tank of the internal heat insulating type, it has been extremely difficult to discover cracks generated in the impermeable layer provided on the inner wall of the tank shell. In case an impermeable layer of a thin metallic sheet is provided at the innermost side of the internal heat insulating layer, a clearance is formed between the impermeable layer and the heat insulating layer into which clearance a gas such as ammonia gas is introduced, and detecting liquid is applied along the seam of the metallic thin sheet of the impermeable layer so that any crack in the seam, if such is generated, can be detected by the detecting liquid.
However, the use of a thin metallic sheet as the impermeable layer is economically disadvantageous, and, in case a clearance is formed between the thin metallic sheet and the heat insulating layer, the thin metallic layer might be subjected to breakage by the movement of the low temperature liquid in the tank caused by the rolling of the ship. To avoid such a defect, it has been proposed to provide in place of the metallic thin sheet an impermeable layer comprised of a synthetic resin layer and a metallic foil applied closely in contact with the surface of the heat insulating layer or to provide a secondary impermeable layer in the interior of the heat insulating layer. However, problems arise in such an impermeable layer that detection of cracks (including pinholes) is extremely difficult.
SUMMARY OF THE INVENTION The present invention aims at avoiding the difficulties in the prior art low temperature liquid storage tank.
Therefore, the object of the present invention is to provide a novel and useful low temperature liquid storage tank having crack-detecting means in which detection of cracks possibly generated in the impermeable layer of the tank can be easily and exactly effected by the provision of sources of radioactive element on the inner wall of the tank shell.
The low temperature liquid storage tank having crack-detecting means in accordance with the present invention comprises at least a heat insulating layer and at least an impermeable layer applied to the inner wall of the tank shell in laminated relationship with each other, the tank being characterized in that a plurality of hermetically sealed sources of radioisotope are secured to the inner surface of the tank shell in spaced relationship from each other.
By the low temperature liquid storage tank having crack-detecting means of the present invention described above, since a plurality of hermetically sealed sources of radioisotope are provided in the distributed condition along the inner surface of the tank shell, any crack which might be generated in the impermeable .ried out thereby greatly improving the security of the tank.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing the hull of a ship in which a low temperature liquefied gas storage tank having crack-detecting means in accordance with the present invention is incorporated;
FIG. 2 is a fragmentary cross-sectional view in enlarged scale showing in detail a portion of the low temperature liquefied gas storage tank of FIG. 1;
FIG. 3 is a diagram showing the results of measurement of the emissivity of radiation given in relation to the conditions shown in FIG. 2; and
FIG. 4 is a fragmentary cross-sectional view showing in more detail the construction of the source of radioisotope shown in circle A in FIG. 2.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring to FIG. I, a primary impermeable layer 3 made of a low temperature resistant material is provided on the inside of the tank shell 1 forming the hull with the interposition of a heat insulating layer 2 of a material such as foamed resin. Ballast tanks B are provided at both the ships sides and the ships bottom. The space L is used to receive the low temperature liquid for storage thereof.
In FIG. 2, a secondary impermeable layer 4 is shown as being provided in the interior of the heat insulating layer Z'arranged between the tank shell 1 and theinnermost primary impermeable layer 3.
In accordance with the characteristic feature of the present invention, a plurality of hermetically sealed sources 5 of radioisotope (only one of which is shown in FIG. 2) are secured to the inner surface of the tank shell 1 in spaced relationship from each other.
The heat insulating layer 2 is divided into a primary heat insulating layer 2a and a secondary heat insulating layer 2b by the secondary impermeable layer 4. As to the material for forming these heat insulating layers 2a, 2b, a material having a superior heat insulating property such as hard polyurethane foam, polystyrene foam and polyethylene foam may be employed.
As to the material for forming the tank shell 1, an ordinary steel for ship construction may be used which is not noted for having a low temperature resistant property. However, as to the material for forming the primary impermeable layer 3 and the secondary impermeable layer 4, a composite low temperature resistant material such as a material sold by the Tradename Aluminilar having metallic foils of a high malleability and a low gas permeability such as aluminum foils laminated with polyester resin and a composite material having glass fibers or carbon fibers combined with polyurethane resin, epoxy resin, silicone resin of polytetrafluoroethylene, tetrafloroethylene copolymer must be used.
Referring to FIG. 4, the hermetically sealed source-5 of radioisotope is secured to the inner surface of the tank shell I by means of bonding agent 6 and received in the recess of the second heat insulating layer 2b. The
sealed container a made of lead of the source 5 is formed with a window 5b opening toward the interior of the tank. A capsule 5c is housed in the container 5a and a predetermined quantity of radioisotope 5d (cobalt 60, for example) is hermetically housed in the capsule 5c.
Thus, when the emissivity of radiation from the source 5 is measured from within the tank at the periodical inspection by a suitable instrument such as a dosimeter, results shown in FIG. 3 are obtained, if cracks CI, CII exist in the primary and secondary impermeable layers 3, 4 as shown in FIG. 2. By the inspection of the values of the peaks a, b in FIG. 3, it can be determined in which of the primary impermeable layer 3 and the secondary impermeable layer 4 the crack is generated, and then, by investigating the positions A, B on the primary impermeable layer 3, the positions of cracks Cl, CII can be easily determined geometrically.
The inspection of cracks as described above can be effected during the construction of the tank. The crack inspection is to be carried out at the time the secondary impermeable layer 4 has been completed and at the time the primary impermeable layer 3 has been completed.
As to the radioisotope to be sealed in the source S, cobalt 60 can be used most easily. In other words, the half life of cobalt 60 is 5.2 years, and, assuming that the depreciation period of the ship having the low temperature liquid storage tank described above is years, the quantity of the radioisotope as the source 5 merely decreases to about one-sixteenth, and the quantity of lane of radioisotope suffices for one source. Thus, the total quantity of the sources in a ship may be in the order of 1 mac thereby permitting the total quantity of the sources to be limited to the degree capable of sufficiently insuring the security of the ship.
I claim:
1. Apparatus, comprising:
wall means defining a liquid storage tank;
at least one layer of heat insulating material laminated to and covering said wall means inside the tank;
at least one layer of low temperature liquid-impermeable material laminated to and covering said one layer of heat insulating material inside the tank;
whereby the tank is adapted for storing low temperature liquid;
a plurality of hermetically sealed sources of radioisotope secured on said wall means in spaced relationship to one another, each source including shielding providing window means oriented toward the inside of the tank, so that cracks in the at least one 4 low temperature liquidimpermeable layer may be detected from within the tank.
2. The apparatus of claim 1, wherein:
the hermetically sealed sources of radioisotope are each constituted by a capsule of cobalt 6O encased in lead.
3. The apparatus of claim 1, comprising:
a second layer of heat insulating material laminated to and covering the first-described layer of layer of low temperature liquid-impermeable material inside the tank; and
a second layer of low temperature liquid-impermeable material laminated to and covering the second layer of heat insulating material inside the tank, whereby,
the second layer of low temperature liquid-impermeable material functions as the primary layer of low temperature liquid-impermeable material and the first-described layer of low temperature liquidimpermeable material functions as a secondary layer of low temperature liquid-impermeable material.
4. The apparatus of claim 1, wherein:
further including a tanker ship for transporting liquefied gas, said ship incorporating said liquid storage tank.
5. The apparatus of claim 1, wherein:
said wall means is constituted by steel.
6. The apparatus of claim 1, wherein:
the heat insulating material is constituted by rigid foamed plastic resin.
7. The apparatus of claim 6, wherein:
the at least one layer of low temperature liquidimpermeable material is constituted by a composite aluminum foil laminated with polyester resin.
8. The apparatus of claim 6, wherein:
the at least one layer of low temperature liquidimpermeable material is constituted by a composite of fiber reinforced polyurethane resin.
9. The apparatus of claim 6, wherein:
the at least one layer of low temperature liquidimpermeable material is constituted by a composite of fiber-reinforced epoxy resin.
10. The apparatus of claim 6, wherein:
the at least one layer of low temperature liquidimpermeable material is constituted by a composite of fiber-reinforced silicone resin.
11. The apparatus of claim 6, wherein:
the at least one layer of low temperature liquidimpermeable material is constituted by a composite of fiber-reinforced polytetrafluoroethylene-tetrafluoroethylene copolymer.

Claims (11)

1. Apparatus, comprising: wall means defining a liquid storage tank; at least one layer of heat insulating material laminated to and covering said wall means inside the tank; at least one layer of low temperature liquid-impermeable material laminated to and covering said one layer of heat insulating material inside the tank; whereby the tank is adapted for storing low temperature liquid; a plurality of hermetically sealed sources of radioisotope secured on said wall means in spaced relationship to one another, each source including shielding providing window means oriented toward the inside of the tank, so that cracks in the at least one low temperature liquidimpermeable layer may be detected from within the tank.
2. The apparatus of claim 1, wherein: the hermetically sealed sources of radioisotope are each constituted by a capsule of cobalt 60 encased in lead.
3. The apparatus of claim 1, comprising: a second layer of heat insulating material laminated to and covering the first-described layer of layer of low temperature liquid-impermeable material inside the tank; and a second layer of low temperature liquid-impermeable material laminated to and covering the second layer of heat insulating material inside the tank, whereby, the second layer of low temperature liquid-impermeable material functions as the primary layer of low temperature liquid-impermeable material and the first-described layer of low temperature liquid-impermeable material functions as a secondary layer of low temperature liquid-impermeable material.
4. The apparatus of claim 1, wherein: further including a tanker ship for transporting liquefied gas, said ship incorporating said liquid storage tank.
5. The apparatus of claim 1, wherein: said wall means is constituted by steel.
6. The apparatus of claim 1, wherein: the heat insulating material is constituted by rigid foamed plastic resin.
7. The apparatus of claim 6, wherein: the at least one layer of low temperature liquid-impermeable material is constituted by a composite aluminum foil laminated with polyester resin.
8. The apparatus of claim 6, wherein: the at least one layer of low temperature liquid-impermeable material is constituted by a composite of fiber reinforced polyurethane resin.
9. The apparatus of claim 6, wherein: the at least one layer of low temperature liquid-impermeable material is constituted by a composite of fiber-reinforced epoxy resin.
10. The apparatus of claim 6, wherein: the at least one layer of low temperature liquid-impermeable material is constituted by a composite of fiber-reinforced silicone resin.
11. The apparatus of claim 6, wherein: the at least one layer of low temperature liquid-impermeable material is constituted by a composite of fiber-reinforced polytetrafluoroethylene-tetrafluoroethylene copolymer.
US47914374 1973-06-22 1974-06-13 Low temperature liquid storage tank having crack-detecting means Expired - Lifetime US3916189A (en)

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CA (1) CA1005375A (en)
DK (1) DK145144C (en)
ES (1) ES427669A1 (en)
FR (1) FR2234514B1 (en)
GB (1) GB1442918A (en)
IT (1) IT1015284B (en)
NL (1) NL7408425A (en)
NO (1) NO133511C (en)
SE (1) SE393862B (en)

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US4051369A (en) * 1974-02-09 1977-09-27 Japan Atomic Energy Research Institute Method for inspecting nuclear fuel rod or irradiation capsule

Families Citing this family (4)

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JPS56132550A (en) * 1980-03-21 1981-10-16 Nippon Steel Corp Diagnostic method for deterioration of insulation for winding of electric machine
FR2515347A1 (en) * 1981-10-26 1983-04-29 Nguyen Tan Chuong Crack detection, esp. in wall of tanker ship carrying liq. methane - where gases are fed through cavities in wall while telemeter makes thermal and gamma ray maps of wall
JPH0740826Y2 (en) * 1989-06-19 1995-09-20 株式会社プランテック Vertical incinerator with gas rectifier
JPH0730905B2 (en) * 1991-09-09 1995-04-10 株式会社ジェット炉 Incinerator

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US2518327A (en) * 1947-01-20 1950-08-08 Bell Telephone Labor Inc Method and means for detecting leaks in lead sheath telephone cables
US2674695A (en) * 1950-07-27 1954-04-06 Sun Oil Co Determination of level of a body of material in a vessel
US2794953A (en) * 1954-02-25 1957-06-04 Budd Co Method and apparatus for testing wall continuity by capacitance alteration
US3439166A (en) * 1964-11-04 1969-04-15 Industrial Nucleonics Corp Measuring ablation shield thickness
US3531638A (en) * 1965-10-23 1970-09-29 Industrial Nucleonics Corp Radiation fill gauge

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JPS4829484A (en) * 1971-08-20 1973-04-19

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2518327A (en) * 1947-01-20 1950-08-08 Bell Telephone Labor Inc Method and means for detecting leaks in lead sheath telephone cables
US2674695A (en) * 1950-07-27 1954-04-06 Sun Oil Co Determination of level of a body of material in a vessel
US2794953A (en) * 1954-02-25 1957-06-04 Budd Co Method and apparatus for testing wall continuity by capacitance alteration
US3439166A (en) * 1964-11-04 1969-04-15 Industrial Nucleonics Corp Measuring ablation shield thickness
US3531638A (en) * 1965-10-23 1970-09-29 Industrial Nucleonics Corp Radiation fill gauge

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4051369A (en) * 1974-02-09 1977-09-27 Japan Atomic Energy Research Institute Method for inspecting nuclear fuel rod or irradiation capsule

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BE816655A (en) 1974-10-16
DK145144B (en) 1982-09-13
IT1015284B (en) 1977-05-10
GB1442918A (en) 1976-07-14
CA1005375A (en) 1977-02-15
DK333074A (en) 1975-02-24
ES427669A1 (en) 1976-09-01
DE2429877A1 (en) 1975-01-16
JPS5020787A (en) 1975-03-05
NO742250L (en) 1975-01-20
FR2234514B1 (en) 1976-12-24
DE2429877B2 (en) 1976-02-19
FR2234514A1 (en) 1975-01-17
NO133511B (en) 1976-02-02
SE393862B (en) 1977-05-23
NL7408425A (en) 1974-12-24
DK145144C (en) 1983-02-14
NO133511C (en) 1976-05-12
SE7407877L (en) 1974-12-23

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