DE2236914A1 - LEAK DETECTION METHOD AND DEVICE FOR DETECTING AND DISPLAYING LEAK LEAKS IN HEAT-INSULATED CONTAINERS - Google Patents

Description

GAZ DE PRANCE ""

MUNICH 7/26 23, rue Philibert Delorme

75 017 - PARIS / FRANCE

"Leak detection procedure and device for plague detection and display, of leakage losses occurring in thermally insulated containers with a large volume. "

The present invention relates essentially to a leak detection method and a leak detection device for locating "or detecting or plaguing sites or investigating leakage losses or Leakage in a container with a large volume or volume that is provided with heat protection and contains a flowable medium.

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Fitability, which flowable medium to a temperature which is very different from that of the external environment of the container, e.g., a very low one Temperature in the case of storage or storage of a liquefied natural gas or any other liquid gas at low temperature.

As. Structural engineering manufactured storage tanks with a large volume or capacity (e.g. from a few thousand to a few tens of thousands of cubic meters or more) for storage or Storage or storage of very strongly cooled or cryogenic, flowable media, in particular liquefied media Natural gas or liquid natural gas often consist of two coaxially arranged cylindrical vessels or envelopes. That inner vessel consists of a cold-resistant ^ metal, such as alloyed stainless steel e.g. nickel steel, aluminum or light metal alloys etc. The space between the two vessels, is with a heat or cold protection agent or heat insulating material filled, which should reduce the heat supply and ensure a progressive increase in those temperatures, which is the temperature of the liquid gas on the wall of the inner vessel and the ambient temperature on the wall of the outer vessel are. This latter wall can therefore consist of a less noble material, since it is resistant to low temperatures does not need to be resilient.

For reasons of economy and handiness, the heat protection agent generally consists of a powder or granular material such as perlite or the like ..

In order to avoid sagging or subsidence or a setting of the powdery heat protection agent, which is caused by dimensional changes caused by the container (in particular by pre-cooling the inner vessel and by exposure to sunlight of the

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outer G-efässes), these 'changes are compensated by that on the outside of the inner vessel an elastic "resp. Flexible cushion or cushion is attached, which is formed, for example, by a fibrous material such as glass wool or rock wool is.

In the case of one type of container, both vessels or covers are closed and are not related to each other. The one filled with the heat protection agent, between the inner vessel and The intermediate space lying between the outer envelope can then by means of a gaseous medium which is capable of flowing away from the cryogenic distinguishing agent such as nitrogen. Under these circumstances the. education or formation of a leakage loss or a leak in the inner vessel due to the appearance within the space, of constituents of the cryogenic or strongly cooled * flowable medium, which after an indefinite variable, Detected or found or detected by a measuring device depending on the size of the leakage loss or found out. It is also not possible to find the exact location of the leakage with this method. to determine.

In another type of container, the gas phase of the inner vessel is between the vessel and the outer casing lying space in connection. As a result, the gas envelope located in the intermediate space comprises the components of the cryogenic flowable medium itself, and it is not possible to the appearance of a leakage or a leak in the inner vessel through an analysis of this gas shell discover or determine.

If there is a leakage in the inner vessel of the container and «which becomes sufficiently significant, one can through that

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Condensation or frost or icing stains formed in the air on the outer wall of the outer casing and under the concrete ceiling or platform, which is usually the container wears appear. Unfortunately, if the leakage loss is significant, it can be irreparable Cause damage to facilities.

The invention aims to obviate these difficulties using simple and economical means for tracking down or finding, detecting, discovering, and for quickly plaguing or displaying each on the inner vessel a heat-insulated container of the above-mentioned types appearing leakage.

The leak detection or testing method according to the invention is thereby characterized in that the leakage losses of the flowable medium within the heat protection means of the container in the immediate Area of the normally tight inner vessel to be channeled and that from place to place around the container heat-conducting sectors, much like the Pehler Ortbe mood of the leak areas permitting heat waves are assigned, are arranged along the thus channeled leakage path. For execution this method can be used by the leak detection or leak testing device according to the invention to determine and display the leakage losses or leaks, one embedded in the heat protection agent and that have a tight envelope surrounding the inner vessel and not far from it, e.g. at a distance of 10 to 20 cm, as well as a number of possibly different, thermally conductive ones around the vessel in the one between the envelope and the vessel located tight space between distributed metallic sectors, and also at least one heat-sensitive probe or a similar sensor or transmitter device, advantageously of the type having a thermocouple, which conducts each of these Sectors is assigned. These sectors are advantageous

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arranged at least in the area of the lower and / or the upper part of the vessel. <

In this way, if there is a leakage or a leak in the inner vessel, it evaporates or vaporizes the liquefied natural gas, in which between the inner vessel and the one extending upwards in the heat protection medium, are sealed ' Sheath located intermediate space, so if necessary flows along the vessel, in which it flows through its own weight or its gravity migrates in the heat protection agent, channeling between the vessel and the envelope forming a tight jacket remain. If the liquefied natural gas-one of the mentioned thermally conductive Sectors reached in the area of a vertical extending through the leak point experiences the associated heat-sensitive Probe a sudden drop in temperature. The end-· Measure of the temperature gradient, its speed as well as the way in which the neighboring, heat-conducting sectors are affected allow the location or location of the leakage to be determined or determined fairly precisely, and also its significance to estimate. or. to investigate. Under these circumstances it is possible to secure the necessary means of the container.

The invention is described in more detail in the following description er. explains with reference to the accompanying drawings, which are only for the purpose of explanation an embodiment of the invention indicate. In these drawings show:

Pig; 1 shows a schematic view in vertical section through a container equipped according to the invention;

Fig. 2 is a view on a larger scale of the circled Detail II on Pig.1; and

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Pig. 3 is a sectional view taken substantially along FIG Level III-III on Pig. 1.

According to the embodiment shown schematically in the drawings, is shown on this a container 10, for example for storing a liquefied natural gas, which on a Concrete ceiling or platform 11 rests, which is itself supported by the ground via concrete piles 13. The storage container 10 comprises an inner vessel 14 made, for example, of stainless steel or an aluminum alloy. This vessel 14 is self-supporting. The vessel 14 rests on an insulating covering 15 » which consists e.g. of inflated or expanded plastic foam, of the kind sold under the name "Foam-glass" will. The insulating covering 15 rests on the concrete ceiling 11. The outer vessel 14 is made of ordinary steel Serving 16 included. The space between the vessel 14 and the envelope 16 is divided into two by a tight jacket 17 Parts, an outer 18 and an inner 19, divided. Of the Space 18 is covered with a powdery thermal insulating material 20, such as e.g. perlite filled. The inner space 19 is covered with an elastically resilient heat-protective fabric 21, for example made of a cushion consists of glass wool or rock wool, filled. The resilient padding 21 is in place between the dense Sheath 17 and a semirigid one made of, for example, a glass fabric Shell 22 held. The elastic padding 21 takes in a manner known per se the different occurring between the inner vessel 14 and the outer casing 16 Thermal expansion. The tight jacket 17 continues under the vessel 14 through a film or thin layer or layer 27. the The connection between the jacket 17 and the film 27 can be seen more clearly in FIG. The coat 17 and the Foil 27 forming material can be tekimt and ramcli mal in dar technology as a secondary or auxiliary seal barrier or shield

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suitable type used. In particular, it can be

complex composite films or layers or plies act, which e.g. from a sandwich or composite laminate from a Aluminum foil lying between two polyethylene foils or a .proven or unproven polyethylene foil. The connection of the film 17 to the film 27 is done, for example, by shark sealing or hot welding or hot gluing, the jacket 17 can consist of superimposed or layered, welded webs with bent edges or edges 17a, as is the case with Eg.2 shows. The connections between the sheets can also be made using glued or welded joint strips will. The jacket 17 is on, e.g. \ in the dome 16a of the outer envelope 16 anchored, heat-insulating hanging struts or ropes 24 attached (Fig. 1).

According to the invention, various heat-conducting metallic sectors 30, 31, 32 are distributed around the container 14 in the sealed space 19 between the jacket 17 and the container 14 or in the immediate area of this space. Accordingly, the metallic sectors 30 are arranged at the lower part of the container and, for reasons of convenience, under the tight jacket 17, 27 vertically below the space 19, illustrated. Metallic sectors 31 are also provided in the space 19 in a manner similar to the sectors 30 distributed _} on the upper part of the container (FIG. 1 ').

According to a modification, horizontal folds or Seams or hollow envelopes are provided on the jacket 17 by which circular arc-shaped rods or tubes with a corresponding radius of curvature and which play the role of sectors 30 to 32, " are led. These rods or tubes could also go through any suitable means, e.g. by means of approaches, rags, appendages

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- 8 or hooks can be attached or attached to the jacket 17.

In the drawings the dimensions are obviously not adhered to or taken into account, the size of the strengths or thicknesses and that between the container 14 and the envelope 16 located rooms has been exaggerated. For example, it can be storage containers with a diameter of several tens Meters, e.g. from about 40 meters. The order of magnitude of the thickness or thickness of the heat protection layer 18 + 19 is usually of about one meter. Twenty circular arc-shaped sectors 30 can for example be provided and evenly arranged around the container be spread around. The sectors can be a few centimeters apart, e.g. by about 2 to 5 cm, so that the temperature one sector does not affect that of the neighboring sector. For example, the sectors can have a width of approximately ten centimeters and a thickness or strength of approximately 5 mm, if they are made of a highly thermally conductive metal such as Made of copper. The relative thickness of the space 19 is relatively weak, for example 20 cm, as the main insulating role the powdery one contained in the largest room Thermal insulating material 20 is allocated. .

Also, every sector is like 30, 31 or 32 at least associated with a heat-sensitive probe, which advantageously consists of a thermocouple, as illustrated schematically at 33 in FIG. 2, consists. The electrical wire conductors 34 are in each suitable manner out to the outside of the container out and summarized on a monitoring switchboard.

In the event of a leakage or a leak in the Vessel 14, the liquefied natural gas channeled into the narrow space 19 partially evaporates at least into the heat insulating material 21 and migrates or flows on there. When the leakage loss is great

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is, the liquid can also by gravity bzxtf. Own weight migrate to the lower part of the room 19 or be transported. In any case, this leakage is a significant cooling of the affected sectors 30, 31 _s 32 cause, that is, those which are within we sent Ii before η in the leading through the leak, radial vertical plane. The thermocouples 33 assigned to the various sectors enable the location of the

affected sectors, as well as the size and the relative cooling speed can be read directly on the board. From all these data or information, one can draw significant conclusions regarding the size and the course of the leakage losses and their location determination.

In particular, although the invention is particularly suitable for storage or conveying containers with large capacities for liquefied. If natural gas is applicable, the invention can also be used for smaller containers with a capacity of e.g. a few tens to a few hundred cubic meters for storing or keeping any cryogenic, flowable medium in the aHganänen

such as: liquefied natural gas, liquid oxygen, liquid Air, liquid nitrogen, etc ...

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Claims (3)

- ίο - PATENT CLAIMS 1.! Method for determining and displaying the leakage losses of a flowable medium contained in a heat-insulated container with a large capacity, which medium is heated to a temperature ; which is very different from that of the outer container environment, is brought to a very low temperature in the case of the storage of a liquefied natural gas or any other gas liquefied at low temperature, characterized in that the leakage losses of the flowable medium in the heat protection means of the container are channeled in the immediate area of its inner, normally tight vessel (14) and that from point to point around the container, heat-conducting sectors (30, 31, 32) along the drainage path of the leakage losses channeled in this way or immediately Area are distributed, these sectors are assigned to heat waves, which enable the location of the defective or leakage areas to be determined. 2. Leak detection or leak testing device for carrying out the method according to claim 1, characterized by a tight, embedded in the heat protection means and the inner G-efäss (14) at a short distance, e.g. around 10 to 20 cm from the ■. same surrounding jacket (17), through different thermally conductive metallic sectors (30, 31 »32), which are located around the vessel, in which between the vessel (14) and the casing (17) tight space (19) or in its immediate Area are distributed, and by at least one heat-sensitive Measuring probe (33), advantageously a thermocouple having type, each of the conductive; Sectors is assigned. 309809/0744 3. Device according to claim 2, characterized in that the conductive sectors (30, 31, 32) at least in the region of the arranged upper part and / or the lower part of the G-efässes are. 4. Device according to claim 2 or 3, characterized in that that the space between G-efäss (14) and jacket (17) with a compressible, resilient, heat-insulating material, such as glass wool, rock wool or the like. is filled. ■■■. "· 309809/0744 L e r s e i t e BAO OR (QINAL