A container made of polymer composite material for an electrically conductive medium with a function for monitoring the tightness of the inner layer

Abstract

This utility model relates to the production of storage and process equipment, specifically to the design of polymer composite tanks for storing and transporting aggressive and non-aggressive conductive media, equipped with integrated inner-layer leakage monitoring devices. The technical result is the ability to continuously monitor the inner-layer leakage of a polymer composite tank during operation with a conductive working medium, as well as to subsequently detect localized inner-layer defects using spark or electrolytic flaw detection.The technical result is achieved in a container made of polymer composite materials for an electrically conductive medium with a function for monitoring the tightness of the inner layer, wherein between the inner layer and the structural layer there is an intermediate conductive composite layer made on the basis of a polymer resin with a carbon filler, located over the entire controlled area of ​​the housing, wherein the content of the carbon filler in the conductive composite layer is selected in such a way that the specific electrical resistance of the conductive composite layer is ensured to be less than 106 Ohm⋅m, and a first electrode connected to the conductive composite layer is brought out to the outer surface of the housing. 1 ill.

Description

[0001] The utility model relates to the field of production of process equipment, in particular to the design of containers made of polymer composite materials for storing and transporting aggressive and non-aggressive electrically conductive media, equipped with built-in means for monitoring the tightness of the internal anti-corrosion layer.

[0002] A known analogue is a container for storing a cryogenic product - US3967256A, containing a tank body with a heat-insulating barrier layer on the wall, conductive elements built into the shell of the body, made in the form of metal sheets, strips or wires located inside the heat-insulating layer, and connected to a voltage source and a measuring unit for periodically measuring electrical resistance or monitoring the integrity of the conductive circuit.

[0003] The disadvantage of this analog is its limited testing capabilities, as the functionality of the embedded conductive elements relies on changes in their temperature and electrical resistance when cooled by a cryogenic product, rather than on the penetration of the working fluid through a defect in the inner layer. Therefore, this analog does not allow for monitoring the tightness of the inner anti-corrosion layer of a container in contact with a conductive liquid, nor does it support the use of the embedded conductive element as an electrode for spark testing of the inner coating.

[0004] An analogue is known - a container for storing liquid with a device for monitoring the integrity of the internal lining - US6662632, selected as a prototype, containing a metal housing that performs the function of a conductive base, an internal non-metallic lining applied to the internal surface of the metal housing, and one or more electrical probes placed inside the container in an electrically conductive liquid, wherein the metal housing and probes are connected to a measuring unit for supplying a measuring voltage and monitoring the electrical parameters of the circuit.

[0005] A disadvantage of the prototype is its limited applicability to non-metallic enclosures, as the metal enclosure serves as the conductive base, which is not inherent in fiberglass tanks. Therefore, it is impossible to embed a special conductive layer into the wall, record its rated resistance during factory testing, and use it for operational monitoring. Furthermore, the design does not provide for the use of the embedded conductive element as an electrode for spark testing of the internal anti-corrosion coating in accordance with GOST 34395-2018.

[0006] The technical result consists in providing the possibility of continuous monitoring of the tightness of the inner layer of a container made of a polymer composite material during operation with an electrically conductive working medium, as well as in providing the possibility of subsequent detection of local defects of the inner layer by the method of electric spark or electrolytic flaw detection.

[0007] The technical result is achieved in a container made of a polymer composite material for an electrically conductive medium with a function for monitoring the tightness of the inner layer, comprising a housing including an inner layer made of a polymer material facing the working medium, intended for contact with an electrically conductive working medium, and a structural layer made of a polymer composite material based on reinforcing materials impregnated with a polymer resin, wherein between the inner layer and the structural layer there is an intermediate conductive composite layer made on the basis of a polymer resin with a carbon filler, located over the entire controlled area of ​​the housing, wherein the content of the carbon filler in the conductive composite layer is selected in such a way that the specific electrical resistance of the conductive composite layer is less than 106 Ohm⋅m, and the first electrode is brought out to the outer surface of the housing,connected to a conductive composite layer.

[0008] Fig. 1 shows a container made of a polymer composite material for an electrically conductive medium with a function for monitoring the tightness of the inner layer, a general view in section: a housing with a three-layer wall including an inner layer 1 made of a polymer material, an intermediate conductive composite layer 2 based on a polymer resin with a carbon filler, a structural layer 3 made of glass fabrics or glass fiber impregnated with a polymer resin, and a first electrode 4, brought out to the outer surface of the housing and connected to the conductive composite layer 2.

[0009] Let's look at an example of the device implementation. The body of a tank with a volume of 10 m 3For storing hydrochloric acid with a concentration of up to 37%, they are manufactured using the mandrel winding method. The inner layer 1 is made of a thermosetting material at least 0.5 mm thick made of a reinforcing material impregnated with a polymer resin with a resin content of at least 30%. Glass veil of type C, ECR, E6CR, E6DR or E glass, carbon veil, carbon fabric or synthetic veil can be used as the reinforcing material of the inner layer. Alternatively, the inner layer can be made of thermoplastic at least 1 mm thick made of polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), fluoroplastic (FEP), polyvinylidene fluoride (PVDF), ethylene-trifluorochloroethylene (E-TFCE), chlorinated polyvinyl chloride (CPVC) or polyphenylene sulfide (PPS), or in the form of rubber coating or acid-resistant tiles (bricks).

[0010] The intermediate conductive composite layer 2 is formed on the basis of a polymer resin with a carbon filler over the entire controlled area of ​​the housing in one of the following ways: by applying resin with dispersed carbon fillers - carbon nanotubes, carbon black (soot) or graphite - with their total content from 0.1 to 5% by weight (when the concentration decreases below 0.1%, the specific electrical resistance of the layer increases until there is no breakdown, with an increase above 5%, processing of the resin is technologically difficult); by introducing chopped carbon fiber into the resin with a total content of at least 5% by weight; laying a carbon veil with a surface density of at least 30 g / m 2 , impregnated with resin; laying carbon fabric with a surface density of at least 150 g / m 2, impregnated with resin. All embodiments of the conductive layer provide a specific electrical resistance of less than 106 ohm⋅m. The first electrode 4 is led from the conductive layer through the wall to the outer surface of the housing and sealed.

[0011] In one embodiment, the conductive layer is sectionalized, divided into several electrically insulated sections, each of which occupies a corresponding portion of the monitored area of ​​the housing and is connected to its own electrode located on the outer surface of the housing. This design allows for the preliminary determination of the location of a defect in the inner layer based on the change in electrical resistance of a specific section.

[0012] Structural layer 3 is formed by winding reinforcing materials impregnated with polymer resin. In the example implementation, the total layer thickness is 6 mm, ensuring the load-bearing capacity of the housing. This thickness may vary and is calculated individually.

[0013] When certifying a finished container, the electrical insulation of the inner protective layer is tested. This is done by measuring the electrical resistance of the circuit between the first electrode, connected to the conductive layer, and the second electrode, located within the container's interior filled with a conductive test medium, such as tap water. If the inner protective layer is not breached, the electrical circuit between the electrodes remains open, and the measured resistance exceeds the upper limit of the device used. This result is recorded in the product's data sheet as the initial state of the sealed inner protective layer.

[0014] Let's consider an example of device application. During operation, the tank is filled with a 20% sodium chloride solution. Periodically, at least once per quarter, a portable resistance meter is connected to the first electrode 4, located on the outer surface of the housing, and to the second electrode, immersed in the working fluid. The measured circuit resistance is compared with the rated value. If the resistance drops below the specified threshold, a leak in the inner layer is detected, and detailed defect localization is performed using spark testing in accordance with GOST 34395-2018, using the conductive layer as a counter electrode. The flaw detector's high-voltage generator is connected to the first electrode, the probe is moved along the inner surface of the tank, and the precise location of the inner layer leak is determined by the appearance of a spark discharge.An application for such a design could be enterprises in the chemical, petrochemical and food industries, where tanks and reservoirs made of polymer composite materials, reactors and collectors for aggressive and conductive liquids are used.

[0015] In the version with a sectional conductive layer, due to the sectional execution of the conductive layer, the search area is reduced and the accuracy of determining the location of the leak is increased.

[0016] The placement of an intermediate conductive composite layer between the inner layer and the structural layer, located over the entire controlled area of ​​the housing, ensures the presence of a permanent built-in electrical conductor in the wall of the container made of polymer composite materials, covering the entire controlled surface, so that if the tightness of the inner layer is broken at any place, the electrically conductive working medium penetrates to the conductive layer and closes the electrical circuit, eliminating the possibility that the defect will be outside the control zone.The implementation of a conductive layer based on a polymer resin with a carbon filler with a filler content that provides a specific electrical resistance of less than 106 Ohm⋅m determines the electrophysical performance of the layer as an element of the measuring circuit: at a given level of conductivity, a measurable current flows through the layer, allowing for recording a decrease in circuit resistance when a leak occurs and comparing it with the rated value, as well as using the layer as a counter electrode in spark testing according to GOST 34395-2018. Exceeding the specified resistance threshold converts the layer into a dielectric and excludes both testing modes.The first electrode, located on the outer surface of the housing and connected to the conductive layer, allows for connecting a measuring instrument or a high-voltage source of a flaw detector to the integrated layer from the outside without compromising the housing's seal, which is essential for both operational monitoring and flaw detection. In this particular case, implementing the conductive layer in electrically isolated sections, each equipped with a separate electrode, allows for separate inspection of individual areas of the housing surface. A decrease in the resistance of a specific section clearly indicates the defect's location in that section, ensuring more accurate leak location and reducing the scope of subsequent flaw detection.

Claims

A container made of a polymer composite material for an electrically conductive medium with a function for monitoring the tightness of the inner layer, comprising a housing including an inner layer of a polymer material facing the working medium, intended for contact with the electrically conductive working medium, and a structural layer of a polymer composite material based on reinforcing materials impregnated with a polymer resin, characterized in that between the inner layer and the structural layer there is an intermediate conductive composite layer made on the basis of a polymer resin with a carbon filler and located over the entire controlled area of ​​the housing, wherein the content of the carbon filler in the conductive composite layer is selected in such a way that the specific electrical resistance of the conductive composite layer is less than 10 6 Ohm⋅m, and the first electrode, connected to the conductive composite layer, is brought out to the outer surface of the housing.

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