GB2143174A - Composite sheet for lining liquid containers - Google Patents

Composite sheet for lining liquid containers Download PDF

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Publication number
GB2143174A
GB2143174A GB08415371A GB8415371A GB2143174A GB 2143174 A GB2143174 A GB 2143174A GB 08415371 A GB08415371 A GB 08415371A GB 8415371 A GB8415371 A GB 8415371A GB 2143174 A GB2143174 A GB 2143174A
Authority
GB
United Kingdom
Prior art keywords
conductive
sheet
composite sheets
electrically
leak
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.)
Granted
Application number
GB08415371A
Other versions
GB2143174B (en
GB8415371D0 (en
Inventor
Horst Kalfa
Bertram Wagner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Didier Werke AG
Original Assignee
Didier Werke AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Didier Werke AG filed Critical Didier Werke AG
Publication of GB8415371D0 publication Critical patent/GB8415371D0/en
Publication of GB2143174A publication Critical patent/GB2143174A/en
Application granted granted Critical
Publication of GB2143174B publication Critical patent/GB2143174B/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
    • B32B3/10Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material
    • B32B3/18Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material characterised by an internal layer formed of separate pieces of material which are juxtaposed side-by-side
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01MTESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00Investigating fluid-tightness of structures
    • G01M3/02Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/04Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
    • G01M3/16Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using electric detection means
    • G01M3/18Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using electric detection means for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators
    • G01M3/186Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using electric detection means for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators for containers, e.g. radiators
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00Layers arrangement
    • B32B2250/033 layers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00Properties of the layers or laminate
    • B32B2307/20Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
    • B32B2307/202Conductive
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00Properties of the layers or laminate
    • B32B2307/20Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
    • B32B2307/206Insulating
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00Containers; Receptacles

Abstract

A composite sheet 27 for lining a liquid container comprises two outer layers of insulating material between which is a central layer 2 which is divided into electrically conductive but electrically separated fields 7 and 8. Each field comprises two networks of conductive pathways 21 and 22 to which, in use, an electrical potential is applied. If a leak occurs the liquid within the container penetrates between two adjacent pathways 21 and 22 and an electric current flows which can be used to initiate a signal indicative of the presence and position of the leak. <IMAGE>

Description

SPECIFICATION Composite sheet for lining liquid containers The invention relates to a composite sheet for lining liquid containers and to a container lined with one or more such sheets.
Containers adapted to contain potentially hazardous liquids maybe provided with a lining which is adapted-to give an indication of a potential leak in the container wall before such a leak actually occurs to prevent the environment being endangered by the liquid running out of the container. It is also desirable to prevent the material of the container wall coming into contact with the liquid in the container in order to protect the container wall from corrosion.
It is known to provide containers for the storage of liquids with conductive plastics sheets. An intermediate layer for leak-protecting linings in storage containers is described in German Gebrauchsmuster DE-GM 7627844 which comprises electrically conductive, air-permeable and robust material. In this construction it is not possible to obtain a signal on the occurrence of a leak which precisely defines the position of the leak. In addition, with such lining sheets changes in electrical conductivity can occur for various different reasons, such as ageing of the sheet and diffusion of media into the sheet. The water authorities also prescribe an exactly definable signal and a determination of the position of a defective area of such containers.
It is thus an object of the present invention to provide a composite sheet for lining a liquid container which enables not only an exactly definable signal to be produced on the occurrence of a leak but also a precise indication of the position of the leak.
According to the present invention a composite sheet for lining liquid containers comprises at least three superposed layers, the two outer layers being electrically insulating and the intermediate layer or one of the intermediate layers being divided into two or more electrically conductive but electrically separated fields for determining the presence of a leak in the container.
Thus in the sheet of the present invention the central layer or one of the intermediate layers is sub-divided into separate conductive regions. An indication of the presence and position of a leak may be initiated when the liquid within the container, which is either conductive or has been rendered sufficiently conductive penetrates into one of the electrically conductive regions. One of the outer layers of the composite sheet which, in use, will be the inner layer in contact with the liquid is preferably characterised by a high chemical resistance so that it can adequately protect the container wall against attack by the liquid within the container. in order to provide satisfactory protection against potential environmental polltion the other outer layer of the composite sheet is preferably manufactured from a non-conductive material with a high extensibility to rupture.It is preferred that each field includes a least two electrically conductive but electrically separated members.
In the preferred embodiment each field includes at least two electrically conductive but electrically separated members, each comprising a conductor network constituted by a plurality of spaced conductive paths connected to a common line substantially in the configuration of a comb, the conductive paths of the networks meshing with but electrically separated from one another and the common lines being remote from one another. In use, an electric potential is applied to the common lines of the conductive networks so that there is a voltage between each two adjacent conductive paths, which voltage is maintained so long as the container is sealed and does not leak at that position.If an appropriate amount of the conductive liquid within the container should penetrate between two adjacent conductive paths then an electric current flows which may be used to initiate an indication of the presence of the leak, the field producing the signal being indicative of the position of the leak.
It is preferred that the edges of the composite sheet are provided with electrically conductive edge members. It will be appreciated that the points of connection of adjacent composite sheets are the positions at which leakage is most likely. Thus in this embodiment of the present invention there are conductive edge members at the opposed edges of adjacent composite sheets which can indicate the presence and position of a leak at the points of connection in a manner similar to the conductor networks referred to above.
The invention also embraces two composite sheets of the type referred to above which are connected together by means of a cover sheet, e.g of rectangular shape, secured to one side of the composite sheets and extending over their junction and a T-shaped member whose head is secured to the other side of the composite sheets over their junction and whose stem extends into the space between the two adjacent edges of the composite sheets. It will be appreciated that any desired number of composite sheets may be connected together in this manner to make up a container lining of any desired size.
The conductive fields and/or edge members may comprise a conductive adhesive layer or a graphite sheet. This in one embodiment of the invention a voltage is applied between the liquid within the container and the conductive fields so that when the inner layer of the composite sheet develops a leak the liquid contacts one of the fields and a short circuit current flows, which current is used to initiate the indication of the presence and position of the leak.
The present invention embraces also a liquid container lined with one or more composite sheets of the type referred to above. In use, the presence and position of leaks may be monitored by means of a micro-computer.
Thus, in use, respective electrical leads extend from each field and each edge section to a micro-computer which can thus readily determine the presence and position of a leak.
The advantages of the construction of the present invention are that the soundness of the container may be precisely and regularly monitored. In addition, it is possible to produce a indication of the position of the leak when one occurs.
Further features and details of the present invention will be apparent from the following description of certain specific embodiments which is given by way of example with reference to the accompanying drawings, in which: Figure 1 is scrap sectional view of composite sheet for lining a liquid container; Figure 2 is a plan view of the composite sheet; Figure 3 is a scrap sectional view showing the connection of two composite sheets; and Figure 4 shows a large number of composite sheets joined together.
The composite sheet 27 illustrated in Figure 1 comprises three layers 1, 2 and 3 with an electrically conductive edge section 4 extending transverse to the planes of the layers and disposed at the edge 9 of the sheet. The lower layer 3 engages, in use the inner wall of a liquid container and comprises an insulating material with a high extensibility to rupture.
The upper sheet 1 faces, in use,the interior of the container and is characterised by a particularly high resistance to chemical attack. The middle layer 2 is electrically conductive and has the construction shown in Figure 2.
Referring now to Figure 2 the conductive sheet 2 comprises two fields 7 and 8 which are electrically separated from one another.
The electrical pathways are shown only on the right hand field 8. The field 8 comprises two conductive networks 25 and 26 each of which comprises a plurality of spaced, parallel conductive paths 21 and 22 respectively which are connected to respective common lines 23 and 24. The conductive paths 21 and 22 are intercalated with one another in the manner of the teeth of combs and the common lines 23 and 24 are connected to terminals or poles 30 and 31. The field 7, which is not shown in detail, is similarly constructed.
In use, the composite sheet lines the interior of a liquid container and a electrical voltage is applied across the terminals 30 and 31. The liquid within the container is electrically conductive or rendered conductive and if a leak should occur in the layer 1 and a sufficient volume of the liquid penetrates between two adjacent conductive paths 21 and 22 a short circuit occurs and a measureable current is produced which can trigger a warning signal and indicate the position of the leak. At the edges 9 and 10 of the composite sheet 27 electrically conductive edge sections or members 13, 14, 1 5 and 16 are mounted which are respectively connected to terminals 1 7, 18, 1 9 and 20. These edge sections serve to monitor leakage at the point of connection of two composite sheets.
Figure 3 shows the connection of two such composite sheets 27 and 27' which are built up from the layers 1, 2 and 3 described above and 1', 2', 3' respectively. Electrically conductive edge sections 4 and 4' are disposed at the adjacent edges 9 and 9' of the composite sheets and connected to respective terminals 11 and 20. The connection is effected by welding or sticking a rectangular sheet 5, which comprises the same chemically resistant material as the sheet 1 and 1', to the two composite sheets 27 and 27'. The lower side of the composite sheets is then welded or stuck onto the head 6 of an inverted T-shaped member whose stem 28 of the T extends into the intermediate space 29 between the two sheets and prevents the adjacent members from contacting one another.
A voltage is applied to the terminals 11 and 20 and thus if conductive liquid leaks into the space 29 there is a short circuit at the connection in question so that a current is produced which indicates the occurrence and the position of the leak.
Figure 4 shows a plurality of fields F1, F2, F3 connected together and the corresponding terminals of the conductive layers, namely F3.1/F3.2, F2.1/F2.2 and F1.1/1.2. Conductive edge sections, which are not shown in the Figure and the associated terminals Rn.3/ R1.3, R2.3/R3.3, Rn.2/R1.2, R2.2/R3.3, Rn.1/R1.1 and R2.1/R3.1 for n tracks are arranged along the joint lines V1 and V2. The various terminals are connected to means for evaluating some change in an electrical parameter indicative of a leak and in this case a respective line leads from each of the terminals referred to above to a micro computer which monitors leakage at the edges and the fields in the manner described above by interrogating the individual pairs of terminals at time intervals and in a sequence which may be selected at will. When a leak occurs the computer initiates an alarm signal and indicates the position of the leak. In the embodiment described above each field comprises two conductive members, each of which comprises a network of electrical pathways but it will be appreciated that each field may comprise only a single conductive member in which event a leak may be indicated when current flows between the conductive member and the liquid.

Claims (9)

1. A composite sheet for lining liquid containers, comprising at least three superposed layers, the two outer layers being electrically insul ating and the intermediate layer or one of the intermediate layers being divided into two or more electrically conductive but electrically separated fields for determining the presence of a leak in the container.
2. A sheet as claimed in claim 1 in which each field includes at least two electrically conductive but electrically separated members.
3. A sheet as claimed in any one of the preceding claims whose edges are provided with electrically conductive edge members.
4. A sheet as claimed in claim 1 or 2 in which each field includes at least two electrically conductive but electrically separated members each comprising a conductor network constituted by a plurality of spaced conductive paths connected to a common line substantially in the configuration of a comb, the conductive paths of the networks meshing with but electrically separated from one another and the common lines being remote from one another.
5. A sheet as claimed in any one of the preceding claims in which the conductive fields and/or edge members comprise a conductive adhesive layer or a graphite sheet.
6. Two composite sheets as claimed in any one of the preceding claims which are connected together by means of a cover sheet secured to one side of the composite sheets and extending over their junction and a shaped member whose head is secured to the other side of the composite sheets over their junction and whose stem extends into the space between the two adjacent edges of the composite sheets.
7. One or more composite sheets for lining a liquid container substantially as specifically herein described with reference to Figures 1 and 2 alone or in conbination with Figures 3 and/or 4 of the accompanying drawings.
8. A liquid container lined by one or more composite sheets as claimed in any one of the preceding claims.
9. A container as claimed in claim 8 in which each electrically conductive field and edge member is connected to a micro-computer adapted to monitor the occurrence and position of a leak in the or one of the composite sheets.
GB08415371A 1983-06-24 1984-06-15 Composite sheet for lining liquid containers Expired GB2143174B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE3322772A DE3322772C2 (en) 1983-06-24 1983-06-24 Composite film for lining liquid containers

Publications (3)

Publication Number Publication Date
GB8415371D0 GB8415371D0 (en) 1984-07-18
GB2143174A true GB2143174A (en) 1985-02-06
GB2143174B GB2143174B (en) 1987-04-29

Family

ID=6202289

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08415371A Expired GB2143174B (en) 1983-06-24 1984-06-15 Composite sheet for lining liquid containers

Country Status (7)

Country Link
BE (1) BE899980A (en)
CH (1) CH665614A5 (en)
DE (1) DE3322772C2 (en)
FR (1) FR2549017B1 (en)
GB (1) GB2143174B (en)
IT (1) IT1177770B (en)
NL (1) NL8401937A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993002950A1 (en) * 1991-08-01 1993-02-18 Tuma Josef Tankschutzbetrieb Combustible liquids storage container
GB2287817A (en) * 1994-03-19 1995-09-27 Lee Forbes Monitoring vessel integrity
WO2006059170A1 (en) * 2004-11-30 2006-06-08 H. Vils Ag System for detecting the defects of a wall coating, and procedure for manufacturing such a system

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2569847B1 (en) * 1984-08-31 1988-02-05 Thomson Csf DEVICE FOR DETECTION AND LOCATION OF WATER INLET FOR MARINE FLUTE
DE4125430C2 (en) * 1991-08-01 1997-01-30 Frank Deponietechnik Gmbh Arrangement of tightness controllable sealing sheets made of plastic, especially for landfills
DE4213070A1 (en) * 1992-04-21 1993-10-28 Ingbuero Rinne Und Partner Twin spaced apart conductor system for capacitance or resistance monitoring of land fill leakage - has sites which have been sealed against random losses of leachate
DE4316436C2 (en) * 1993-05-17 1995-03-16 Braas Gmbh Composite film for the electrical detection of a leak
DE19512434A1 (en) * 1995-04-03 1996-10-10 Ullrich Dipl Ing Stein Protective coating checking device for fault location
DE102011112228A1 (en) * 2011-09-01 2013-03-07 Martin Wolf Method for temporal and/or aerial detection of cracks in structural component e.g. rotor blade, involves applying conductive liquid on component so that conductive structures are electrically connected when crack is formed

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1419027A (en) * 1972-07-17 1975-12-24 Buckbee Mears Co Method and apparatus for manufacturing multi-layered electrical circuit
GB1461191A (en) * 1973-01-15 1977-01-13 Sun Chemical Corp Shielding tapes
GB1496384A (en) * 1974-02-15 1977-12-30 Du Pont Laminated structure
GB1546609A (en) * 1975-05-28 1979-05-23 Pirelli Screened cable elements
GB1580740A (en) * 1977-06-28 1980-12-03 Haley & Weller Ltd Electrical contact panels

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE7627844U1 (en) * 1900-01-01 Wilhelm Reisgies Kg, 5090 Leverkusen
DE1931748U (en) * 1965-08-05 1966-01-27 Aerotronic Entwicklungen John ELECTRONIC LEAK WARNING DEVICE.
US3383863A (en) * 1966-08-03 1968-05-21 Joe R. Berry Pond, tank and pit liner and method of detecting leaks
JPS5988634A (en) * 1982-11-12 1984-05-22 Hitachi Ltd Leak detecting apparatus for lining tank

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1419027A (en) * 1972-07-17 1975-12-24 Buckbee Mears Co Method and apparatus for manufacturing multi-layered electrical circuit
GB1461191A (en) * 1973-01-15 1977-01-13 Sun Chemical Corp Shielding tapes
GB1496384A (en) * 1974-02-15 1977-12-30 Du Pont Laminated structure
GB1546609A (en) * 1975-05-28 1979-05-23 Pirelli Screened cable elements
GB1580740A (en) * 1977-06-28 1980-12-03 Haley & Weller Ltd Electrical contact panels

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993002950A1 (en) * 1991-08-01 1993-02-18 Tuma Josef Tankschutzbetrieb Combustible liquids storage container
GB2287817A (en) * 1994-03-19 1995-09-27 Lee Forbes Monitoring vessel integrity
WO2006059170A1 (en) * 2004-11-30 2006-06-08 H. Vils Ag System for detecting the defects of a wall coating, and procedure for manufacturing such a system
CN101111753B (en) * 2004-11-30 2010-06-23 H.维尔斯股份公司 System for detecting the defects of a wall coating, and procedure for manufacturing such a system

Also Published As

Publication number Publication date
DE3322772C2 (en) 1986-05-22
IT1177770B (en) 1987-08-26
BE899980A (en) 1984-10-15
IT8448287A0 (en) 1984-05-30
GB2143174B (en) 1987-04-29
FR2549017A1 (en) 1985-01-18
FR2549017B1 (en) 1987-01-09
DE3322772A1 (en) 1985-01-10
GB8415371D0 (en) 1984-07-18
NL8401937A (en) 1985-01-16
CH665614A5 (en) 1988-05-31

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PCNP Patent ceased through non-payment of renewal fee