Heat-indicating clip

Abstract

The technical solution relates to devices for registering when a threshold temperature has been exceeded, and more particularly to devices provided in the form of a clip that makes it possible to register the fact that wires or other items of electrical equipment have exceeded a given temperature. The present device for registering when a threshold temperature has been exceeded is provided in the form of a base that is non-transparent to at least a part of the visible light spectrum, said base being in the form of a clip and being partially covered on the front surface thereof by a heat-sensitive material that undergoes an irreversible change in transparency relative to an initial state when heated to a threshold temperature. The technical solution makes it possible to increase the operational safety of electrical equipment by quickly, reliably and accurately revealing faults related to excess heating, where the fact that an item of electrical equipment has exceeded a given temperature threshold is irreversibly registered by a device that can be easily and reliably installed on a wire and on other items of electrical equipment.

Description

[0001] Temperature indicator clip

[0002] Field of technology

[0003] The technical solution relates to devices for recording the excess of a threshold temperature, namely to devices that are clips that allow irreversible recording of the fact that wires and other elements of electrical equipment have exceeded a specified temperature.

[0004] State of the art

[0005] An increase in temperature is one of the first and most common signs of developing defects in various equipment, such as an increase in transient contact resistance in the electric power industry, malfunctions in bearings in mechanics, interturn short circuits in the winding of electric motors, failure of chargers or batteries in household appliances. Timely detection of such overheating allows for early elimination of the malfunction, preventing damage to equipment, emergency situations and related fires or shutdowns. Technical and regulatory documents establish maximum permissible temperatures, heating above which should be considered a defect requiring immediate cessation of operation and removal of the equipment for repair (for example, RD 34.45-51.300-97, RD 153-34.0-20.363-99, GOST 8865-93, 8024-90, 10693-81, 2213-79, 10434-82, 16708-84, 2585-81, 32397-2020, 26346-84, 839-2019, GOST R 51321.1-2007, etc.).

[0006] It is especially important to detect overheating of wires in 220-380 V electrical panels of residential, social or industrial buildings and structures at an early stage, since such panels, as a rule, have a large fire load, and fires that occur in electrical panels can lead to a major fire, material damage and loss of life.

[0007] Various diagnostic methods are used to detect defects associated with exceeding the maximum permissible temperatures of electrical equipment and wires. Continuous overheating monitoring means include chemical or mechanical temperature indicators, which can be of two types: reversible (changing their appearance only when heated and returning to their original state upon cooling) and irreversible (changing their appearance after exceeding a specified temperature and retaining their original state after cooling). Structurally, most temperature indicators are stickers with a heat-sensitive layer applied to their front surface. An example of such overheating monitoring devices is the invention described in document US7600912B2 (publication date 20.03.2007) and representing a single-layer or double-layer sticker, the heat-sensitive element of which contains leuco dyes and a developer in a binder.When a certain temperature is reached, the binder melts and the developer reacts with the dye, coloring the label. After the temperature decreases, the dye crystallizes and the color is restored. The peculiarity of this kind of inventions is that they allow information only about the current heating temperature, and not about the maximum temperature to which the controlled element of electrical equipment was heated at the moment of maximum load.

[0008] Unlike reversible indicators, irreversible indicators allow not only to detect, but also to record the fact of exceeding the threshold temperature. The use of irreversible thermal indicators allows to assess the condition without creating a maximum load mode, both on operating equipment and on equipment taken out for repair.

[0009] Irreversible heating indicators can be classified by their operating principle. There are indicators based on mechanical destruction of the heat-sensitive element, on the chemical reaction of the components of the thermal composition or on the phase transition of the heat-sensitive component.

[0010] An example of a temperature indicator based on mechanical destruction is described in the source [US6176197B1, publication date 02.11.1998], according to which the temperature indicator is a closed hollow transparent elongated tube with two compositions of different colors, isolated from each other by a polymer partition having a melting point close to the melting points of the compositions. When a given threshold temperature is reached, the partition is destroyed, the compositions melt and mix. As a result, the color of the tube contents changes. The features of the invention include the impossibility of monitoring overheating of the entire surface.Such products are not suitable for detecting short-term overheating, as they are characterized by a long response time: to complete the color transition, it is necessary not only to completely melt the indicator compositions and the polymer membrane separating them, but also to spend time mixing the resulting liquid phases, which can be difficult due to slow diffusion processes near the melting point. The design features of the described invention do not allow for the creation of a flexible device that fits tightly to the entire controlled surface, and do not imply any fastening elements that allow for reliable fixation of the device.

[0011] The chemical reaction of etching a metal substrate with an activator, which begins when a certain temperature is reached, is described in the patent [EP2288879B1, date of publication 04.06.2008]. The indicator changes color from silvery white or mirror to colorless and can be used to control the temperature in food and medical products, as well as in electrical equipment. The metal layer and the activator layer can be applied to a thin film made in the form of a sticker, which ensures the flexibility of the product and the ability to attach to various surfaces. Among the commercially available indicators, the principle of which is based on a chemical reaction, one can highlight the Retomark indicator stickers, supplied by YALOS Innovation Company LLC.

[0012] (https: / / www.yalosindicator.com / product / termoindikatory-kontrol-temperatury).

[0013] The presented irreversible temperature indicators, the principle of which is based on chemical reactions, are characterized by low accuracy, since in accordance with the Arrhenius equation, the rate of a chemical reaction is determined not only by temperature, but also by time. At the same time, the above standards regulate specific temperature thresholds with an accuracy of at least 5 °C, regardless of the time of exposure to temperature, which makes the described inventions unsuitable for registering defects in electrical equipment. Another feature of such devices is the presence of a pronounced dependence of the response time on temperature: with short-term heating to the threshold value, the chemical reaction may not be completed and the indicator color change will either not occur or will be insufficient for detection.In addition, due to the reversibility of color transition reactions, it is possible to return the original color of the indicator that has been triggered after prolonged exposure to low temperatures.

[0014] A separate disadvantage of indicators based on mechanical or chemical principles is that when the layer of the temperature-sensitive element is deformed, the indicator may be triggered prematurely, and their initial implementation in the form of devices with a shape other than flat is not always possible.

[0015] The most accurate temperature indicators are those based on phase transition, namely, on the melting of a heat-sensitive component. Since, unlike a chemical reaction, the phase transition temperature does not depend on the time of exposure, such indicators have the greatest accuracy and are capable of maintaining the initial state for a long time at a temperature slightly lower than the threshold.

[0016] Irreversible indicators based on the principle of phase transition of a temperature-sensitive component can be made in the form of a temperature-indicating paint. A thermochromic indicator containing a substrate and a coating with particles of a solid crystalline material, air voids and a small amount, for example 5-40% of the coating weight, of a binder, is described in source US2010247900A1, publication date 30.09.2010. In this case, the size of the material particles should be such that the coating has high opacity at a temperature below the melting onset temperature due to scattering of visible light, which decreases upon reaching the melting onset temperature with the formation of a transparent coating upon reaching the melting end temperature. A special feature of this invention is a large temperature range at which the transparency changes, as well as a long response time of the device.

[0017] Temperature indicator paints or varnishes can be applied to a surface of any shape. The use of temperature indicator paints and varnishes, the operating principle of which is based on the melting of the pigment, is described in a number of documents, including, for example, CN112322134A (date of publication 09 / 23 / 2020), CN111849346A (date of publication 07 / 11 / 2020), CN108610694A (date of publication 12 / 09 / 2016), SU1765145A1 (date of receipt 10 / 30 / 1989), SU576334A1 (date of publication 05 / 25 / 1976). As a rule, such paints consist of synthetic resins, fillers and heat-sensitive components dispersed in water or solvent. When heated above a given temperature, the heat-sensitive component melts, which changes the color of the composition due to a change in the refractive index. As a rule, after cooling, the color of such compositions does not change or changes insignificantly, which makes it easy to record the fact of overheating during a visual inspection.Indicator paints have a number of features, which include: - it is impossible to indicate the temperature on the paint. During a visual inspection of the equipment, the operator can only see the fact that the temperature has been exceeded, but cannot determine the numerical value of the exceeded threshold. For this, special notes must be made.

[0018] - flow of indicator paint when the threshold temperature is exceeded. When exposed to temperature and the heat-sensitive component melts, the paint may flow from the surface and get onto open elements of the electrical installation or moving elements of the mechanisms, which may lead to a short circuit or the creation of an insulating environment between the contacts, a decrease in the electrical strength of the insulation, heating, jamming, failures, fires and other accidents.

[0019] - the impossibility of applying a uniform layer to complex surfaces. The consequence of this is the impossibility of determining the exact temperature, since the thicker the layer, the higher the difference between the surface temperature and the phase transition (action) temperature.

[0020] - low adhesion and difficulty in applying paint to wires made of non-adhesive materials (silicone, polyethylene, fluoroplastic). A large amount of hot-melt pigment, necessary for a clear visualization of overheating, usually leads to a decrease in the proportion of polymer binder in the composition and reduces paint adhesion. This leads to the fact that the composition is easily separated from the controlled surface under mechanical influences.

[0021] - dependence of the paint response temperature on the chemical composition of the surface to which it is applied. Since the paint comes into direct contact with the material to which it is applied, for example, cable insulation or the paint coating of the engine housing, various substances, primarily fire retardants and plasticizers, can be extracted into the temperature indicator paint. Such substances can lead to the formation of eutectic mixtures with a hot-melting component or otherwise affect the response temperature.

[0022] Another version of the design of temperature indicators based on the phase transition of a heat-sensitive component are heat-indicating stickers. Heat-indicating stickers are free from a number of disadvantages inherent in indicator paints. Thus, the response temperature can be indicated on the sticker. The heat-sensitive composition and adhesive layer are applied in factory conditions in a uniform thin layer on a polymer base. This approach ensures the specified response and adhesion characteristics regardless of the operating conditions. The polymer base prevents contact of the heat-sensitive composition with the surface of the controlled element. In addition, most heat-indicating stickers are additionally covered with a polymer film that protects the hot-melt composition from mechanical or chemical effects and does not allow it to flow down when melting after response. Among the main manufacturers of heat-indicating stickers, the following can be distinguished: OOO TermoElektrika (https: / / www.lesiv.pro / %D0%BA%D0%BE%D0%BF%D0%B8%D1%8F-l-mark-pro), 000 "Innovative company "YALOS".

[0023] (https: / / www.yalosindicator.com / product / termoindikatory-kontrol-temperatury), ZAO NPF Luminophor (https: / / luminophor.ru / catalog / termoindikatomye-materialy / termoindikatory- pl avl eniy a-marki -tin / ).

[0024] As noted earlier, temperature indicators are used in a wide variety of areas. The highest technical requirements are imposed on temperature indicators used in the electric power industry.

[0025] Thus, for the safe use of temperature indicators in the electric power industry, the device must have a number of necessary characteristics: have low flammability and combustibility; have high electrical strength and dielectric properties; irreversibly register the excess of threshold temperatures; ensure the necessary response accuracy; be flexible and durable; have good fixation on the controlled element for tight adhesion to various surfaces.

[0026] At the same time, a device with such characteristics can be used in any other field.

[0027] For the most rapid and reliable detection of defects accompanied by overheating of electrical equipment elements, tight contact of the temperature indicator with the controlled surface is required, without air gaps that reduce the speed and efficiency of heating the temperature indicator due to the low thermal conductivity of air. In addition, temperature indicators should be conveniently and securely attached to the controlled elements, without peeling off from them during operation.When using temperature indicators to register the excess temperature of the surface of electrical equipment elements or various mechanisms, it is necessary to take into account that the surface of such elements often has a complex geometry with a curvature radius of 2 mm (e.g. small-section electric wire cores with or without insulation, steel-aluminum wires of overhead power lines, hardware clamps, the surface of coils, blades of bolted contact connections, contact lamellas, jaws of fuse contact connections, etc.). The surfaces of metal conductive elements can constantly expand / contract due to multiple heating / cooling cycles caused by changes in load current.

[0028] The installation of thermal indicator stickers on contact connections of wires and other elements of electrical equipment with a small radius of curvature leads to a large deformation of both the material of the sticker itself and its adhesive layer, as well as the heat-sensitive layer. This may lead to the fact that after the pressure with which this sticker was glued to the curved surface is removed, the elastic force will exceed the adhesion (the adhesive force of the sticker to the surface), as a result of which the sticker will tend to take its original shape and partially (completely) peel off from the surface. The same can happen when the linear dimensions of the controlled surface change, including due to the thermal expansion of the surface material when it is heated.

[0029] Manufacturers of temperature indicator stickers often indicate in their documentation the need to mount their products on flat surfaces, which is associated not only with their insufficient flexibility and elasticity, but also with the fact that deformation may result in a loss of the functional properties of heat-sensitive materials. Such stickers cannot be used for temperature control of surfaces with a small radius of curvature, surfaces of complex shape, as well as surfaces capable of changing their linear parameters, since the reliability of registering excess temperatures will be significantly reduced.

[0030] The reasons for this are: in case of using heat-sensitive materials based on membrane destruction, premature triggering may occur due to additional load on the membrane or physical damage to the integrity of the device elements during installation; when the sticker is deformed, the heat-sensitive material may peel off from the base, as well as cracks may form on its surface. As a result, false triggering will occur or a decrease in the visibility of the triggered device will be observed, caused by insufficient heating of the heat-sensitive material at the moment the threshold temperature is exceeded; in the area of ​​peeling of the sticker from the controlled surface, an air bubble may form, which will act as thermal insulation.The latter may result in the “failure to operate” of the thermal indicator due to the difference in temperatures between the monitored surface and the heat-sensitive material or a decrease in the response speed; uneven heating of the surface of the heat-sensitive material in the area of ​​sticker peeling off, in which part of the layer of heat-sensitive material changes its appearance (becomes transparent with the color of the base showing through), while part retains its original (opaque) state, which may lead to an unreliable conclusion about the localization of the registered overheating.

[0031] The base of the temperature indicator device and the temperature-sensitive layer itself must have a minimum thickness that ensures rapid heating of the indicator layer and a change in its appearance. This is necessary to register short-term emergency heating caused, for example, by starting currents or short-circuit currents, excessive starting load of engines, cold running, switching or other processes. In addition, the minimum thickness of the temperature indicator sticker is necessary to ensure the necessary heat dissipation from the controlled surface. Otherwise, installing the temperature indicator will lead to an additional increase in the temperature of the controlled element and an increase in the rate of defect development.

[0032] Among the known state-of-the-art solutions, one can highlight devices for visually recording the fact of local overheating of the surface of equipment elements, made in the form of a sticker with a flexible base no more than 1 mm thick and a response speed of the heat-sensitive composition of less than 5 seconds when heated above the threshold temperature [RU2022113312, publication date 05 / 18 / 2022]. At the same time, the overheating registration time during rapid heating of devices to a temperature 5 ° C higher than the registered one is less than 5 seconds, which ensures the indication of defective units even during short-term overheating under conditions of peak loads of the monitored units. However, despite the advantages of thermal indicator stickers described above, their main disadvantage is the difficulty of mounting on the wires of electrical panels. Existing requirements of regulatory documents allow a compact (close) arrangement of wires inside electrical panels, especially near contact connections.It is not always possible to wrap an adhesive thermal indicator sticker around a mounted wire. Mechanical impact on the wires when installing the sticker may result in poor contact quality due to loosening of the contact connection or partial removal of the wire from the terminal under the effect of the applied force. This will result in reduced reliability and increased risk of fire. It should be noted separately that winding thermal indicator stickers on a live wire (without disconnecting from the network) may pose a danger to the installer. When winding a thermal indicator sticker on a wire, it is not always possible to predict in advance the final location of the temperature-sensitive elements. Displacement of the indicator points may result in a decrease in the visibility of the response during inspections, a missed defect and a decrease in reliability.In case of poor fixing of the thermal indicator sticker on the surface of the wire, peeling or reduction of the sticker's adhesion density may occur. Peeling and loss of the functional properties of thermal indicator stickers may also occur when the linear dimensions of the controlled surface change, including due to the thermal expansion of the surface material when it is heated by electric current. This is especially relevant in distribution networks, the load of which varies significantly during the day.

[0033] The reliability of fastening and the safety of using temperature indicator stickers are directly related to the adhesive strength of the sticker (adhesion) to the surface on which they are installed. Adhesion is ensured by the quality of the adhesive layer, the material from which the surface is made, as well as the presence of pollutants or special coatings on it. In some cases, the materials from which the wires or other elements are made have special anti-adhesive coatings, to which it is impossible to reliably attach temperature indicator stickers. Certain difficulties may be associated with the adhesive layer. It can lose its properties over time, adhesion can significantly deteriorate with increasing temperature. Moreover, the glue itself can melt, leak, get inside the terminal and create an insulating layer between the contact and the terminal, and thereby accelerate the development of the defect.Finally, the use of an indicator with an adhesive layer significantly complicates the process of dismantling a triggered thermal indicator, or a thermal indicator beyond its service life, as well as when repair work is required.

[0034] The above-mentioned shortcomings can be eliminated by using a device for monitoring overheating of electrical equipment elements, which is a clip made of a thermochromic material that irreversibly changes its color when heated above the threshold temperature, which is easy to install, in particular, on electrical wires. This device was selected as a prototype of the declared technical solution [https: / / iriss.com / safe-connect-thermochromic-solution / thermo-clip-series / ]. The clip material contains 5-10% of a thermochromic composition that provides an irreversible color change, and 90-95% of non-halogenated polypropylene, which has self-extinguishing properties and high dielectric strength. The clip is designed to be installed on the external insulation of an electrical cable by snapping into place with a small amount of force. It can be safely mounted on monitored live electrical equipment elements.Depending on the size, the described devices can be installed on wires with a diameter of 2.3 to 31 mm. Since the clip is secured by the elasticity of the material from which it is made, such an indicator can be reliably used on wires operating with variable load, i.e. in a wide range of temperatures.

[0035] The principle of operation of the thermochromic composition of the product described above is apparently based on the melting of pigment crystals, followed by the dissolution of the liquid pigment melt in the matrix material when the threshold temperature is reached. After cooling, the pigment solution does not crystallize into its original state, which ensures the preservation of the appearance of the triggered product. The initial color change temperature of the clip in question is 53 °C, the accuracy of the color change start declared by the manufacturer is + / - 1 °C, and the clip response range is 18 °C, since, as stated in the technical characteristics of the described device, a complete irreversible change in the color of the clip occurs at 71 + / - 1 °C. It should also be noted that the narrow range of response temperatures of the clips given in the prototype does not allow them to be used to assess the state of contacts and contact connections of electrical equipment.The time during which the clip (color transition) proposed in the prototype is triggered is up to 20 seconds, which does not allow recording short-term overheating of the controlled elements, which may lead to false triggering or failure of the product. In addition, the prototype device does not indicate the color transition temperature, which makes it impossible to determine the maximum temperature to which the controlled elements were heated at the time of inspection without using additional reference books or technical documentation.

[0036] Based on the level of technology that we have studied in detail, it follows that, despite the large selection of temperature indicators, which differ both in their mechanism of action and in their design, there is a need for devices for recording the excess of the threshold temperature of electrical wires that are convenient and safe to install and operate, and have:

[0037] - high accuracy and response speed,

[0038] - irreversibility of operation,

[0039] - low flammability and combustibility,

[0040] - high electrical strength and dielectric properties,

[0041] - flexible, durable and able to be securely attached for tight adhesion to various surfaces.

[0042] In this case, the operating principle of such indicators should be based on the melting of a heat-sensitive component, ensuring:

[0043] - maintaining the original state at a temperature slightly below the threshold,

[0044] - independence of the response temperature from the exposure time,

[0045] - no premature triggering.

[0046] The technical solution is aimed at creating a safe, convenient and easy to install and operate device for irreversible registration of the fact of exceeding the threshold temperature in electrical installations, made in the form of a clip.

[0047] Terms and definitions used in this technical solution

[0048] A “clip” is understood to mean an element made in the form of a three-dimensional figure with a through internal cavity, preferably circular in cross-section, in which a cut is made that allows the clip to be installed on cylindrical or other objects with a circular cross-section, without the use of additional fasteners. In relation to the present technical solution, a clip is understood to mean a product with a cut, intended for placement on electrical wires, the fixation of which occurs due to elastic properties, and installation or removal from the wire can occur by snapping the clip onto the wire, without the stage of threading the wire through the clip.

[0049] “Thermal indicator clip” is a device made in the form of a clip and with the ability to register the excess of a specified threshold temperature by the element on which it is installed due to heat-sensitive elements located on the clip, built into it or included in the material from which it is made.

[0050] The term "thermosensitive material" is understood to mean a material that becomes more transparent to at least part of the visible light relative to the initial state when heated above a threshold temperature, and does not return to the initial state after subsequent cooling. The thermosensitive material may consist, for example, of an individual organic compound or a salt of an organic acid that undergoes a phase transition upon reaching a threshold temperature, or of a mixture of substances. In addition, the thermosensitive material may additionally include a binder, represented, for example, by organic resins, for better adhesion of the thermosensitive material to a flexible base, and other additives.

[0051] In this technical solution, the term “glazing” is used to denote the process of forming a uniform layer of one thermodynamic phase around a particle of another thermodynamic phase.

[0052] The term “threshold temperature” or “threshold temperature value” denotes the numerical value of temperature at which an irreversible change in the properties of a heat-sensitive material occurs. In the claimed technical solution, the accuracy of recording the excess of the threshold temperature is 5 °C.

[0053] The term “accuracy of recording the excess of the threshold temperature” means the following:

[0054] 1. Until the device reaches a temperature equal to the threshold temperature of the corresponding heat-sensitive material minus the declared accuracy value, there is no change in the transparency of the corresponding heat-sensitive material or in the appearance of the device.

[0055] 2. At a temperature equal to or greater than the threshold temperature of the corresponding temperature-sensitive material plus the declared accuracy value, the corresponding temperature-sensitive material is transparent and the device takes on an appearance different from the original.

[0056] 3. The exact value of the phase transition temperature of the temperature-sensitive component is within the declared range and is not additionally established. The accuracy of recording the excess of the threshold temperature determined by this technical solution is 5 °C.

[0057] “Phase transition” is the transition of a substance from one thermodynamic phase to another when external conditions change.

[0058] In this technical solution, the term “triggering” is applied to a heat-sensitive material that has undergone a phase transition with an increase in transparency. A device in which the heat-sensitive material has changed transparency is designated as “triggered”.

[0059] “Defect” is a non-compliance of an object with the requirements established by the documentation for at least one indicator.

[0060] “Fire resistance” refers to the ability of a material to resist combustion when exposed to an ignition source.

[0061] The term “electric strength” defines the property of a given device to withstand the electric voltage applied to it. In other words, electric strength is the minimum electric field strength at which the breakdown of the device occurs.

[0062] The term “dielectric” means the property of a given device to withstand an electrical voltage applied to it, while the minimum electric field strength at which the breakdown of the device occurs exceeds the electrical strength of air.

[0063] The term “elasticity” describes the ability of a solid material to return to its original shape during elastic deformation, i.e. an elastic material is deformed after an external force is applied to it, but regains its original shape and size after the effect of this force ceases.

[0064] The term “fast heating” corresponds to the heating of the surface with the device installed on it at a rate of at least 1 °C / sec. The absolute value is selected by experts based on the heating rate of electric wires during emergency conditions, short-circuit currents or starting currents. The term “transparent” refers to the property of the material to transmit more than 90% of the light falling on it. The term “opaque” characterizes the material that transmits no more than 50% of the light falling on it.

[0065] The term “elasticity” reveals the ability of a material to repeat its shape when bent around a cylindrical surface without losing its functional properties. The term “tensile / compressive elasticity” refers to the preservation of the functional properties of a material when a force is applied in any direction in a plane parallel to the plane of the material, as well as after the force is removed.

[0066] The term "flexible base" refers to materials that have the ability to return to their original shape when bent.

[0067] The terms “elastic base” and “elastic protective film” characterize the base material or protective film, which refers to materials that have the ability to change their shape without breaking under external influence.

[0068] The term “complex geometry surface” means any curved surface containing bends, kinks and other nonlinear elements with a minimum radius of curvature of 2 mm. In this technical solution, a cylindrical surface with longitudinal waves with a radius of curvature of an individual bending element of R = 2 mm is considered as a model surface of complex geometry.

[0069] The term “radius of curvature” of curved and cylindrical surfaces is understood to mean the maximum radius of the circular arc that best fits these surfaces. In the context of this technical solution, “small radius of curvature” means a radius of curvature of 2 mm.

[0070] The term “cylindrical surface” refers to a developable closed or open ruled surface formed by the parallel movement of a straight line along some curvilinear guide.

[0071] By "elongation before breaking" is meant the numerical value of the elongation of a product or its parts when stretched, above which its physical integrity is violated and a break occurs. The value is expressed as a percentage, indicating how much the linear dimensions of the material increase when it is stretched relative to the corresponding original dimensions.

[0072] "Microstructure" is the spatial arrangement of particles or individual phases of a material, reflecting the shapes and orientation of the particles that make up the material. Unlike the chemical structure or nanoparticles, the microstructure determines only the physical, optical and mechanical properties of the material, but does not affect the chemical properties of the substances that make up the microstructure. In the context of this technical solution, "irreversible change in microstructure" means an irreversible change in the physical, optical or mechanical properties of the material relative to its initial state, accompanied by a change in its microstructure, i.e. the spatial arrangement of particles or individual phases of the material, their size or shape, up to the complete fusion of the particles and the formation of a single phase.

[0073] The term “maximum temperature surface profile” refers to an image that shows the distribution of maximum temperature field values ​​on the monitored surface and allows one to determine the areas of the surface that have been heated above threshold temperatures for a given period of time.

[0074] The term “solid phase” describes a material structure containing solid particles of arbitrary shape, each of which has at least one point, face or edge in contact with an adjacent particle and connected to each other in such a way that each element of the solid phase can be connected to another element by a single broken line, each point of which is located within this phase. Depending on the shape and size of the solid particles, the continuous solid phase can have a cellular, granular, fibrous, crystalline or flaky structure.

[0075] The term "continuous gas phase" characterizes the mutual arrangement of voids and means that the voids are predominantly "non-isolated" ("connected") and communicate with each other through openings, pores or channels. As applied to the present application, a predominantly continuous gas phase is understood to mean such an arrangement of voids within a heat-sensitive material, in which the volume of voids connected to each other and forming a continuous gas phase exceeds the volume of isolated voids.

[0076] The term “a substance that causes a change in the transparency of a heat-sensitive material when heated above a threshold temperature” means an individual substance that is part of a heat-sensitive material and has a phase transition temperature near the threshold temperature, the presence of which causes a change in the appearance of the temperature indicator when the threshold temperature is reached, and the removal of which from the heat-sensitive material results in the loss of the properties of an irreversible change in transparency when the threshold temperature is reached.

[0077] The essence of the technical solution

[0078] This technical solution is designed to improve the safety of electrical equipment operation, using a simple, safe and easy-to-install device made in the form of a clip, designed for fastening to wires or other elements of electrical equipment, allowing for the rapid, reliable and accurate detection of defects associated with excessive heating, by irreversibly recording the fact that the controlled element of electrical equipment has exceeded a specified threshold temperature.

[0079] The objective of this technical solution is to create such a device, made in the form of a clip.

[0080] The technical result of the declared technical solution consists in increasing the safety of operation of electrical equipment.

[0081] The specified technical result is achieved through fast, reliable and accurate visual detection of defects associated with excessive heating, by means of irreversible registration of the fact that an element of electrical equipment has exceeded a specified threshold temperature, a device that is convenient, reliable and safe to install on wires and other elements of electrical equipment.

[0082] The technical result is achieved by means of a device for registering an excess of a threshold temperature, including a base that is opaque at least to part of the visible light, made in the form of a clip, partially covered on the front side with a heat-sensitive material that irreversibly changes transparency relative to the initial state when heated above the threshold temperature.

[0083] The claimed device has the properties of irreversible heat-sensitive indicators, the principle of which is the melting of the heat-sensitive material, accompanied by a change in transparency relative to the initial state when heated above the threshold temperature. The use of such a principle of overheating registration ensures fast, reliable and reliable detection of defects associated with excessive heating. The proposed device is made in the form of a clip to ensure its convenient, reliable and safe installation, replacement or dismantling on wires and other elements of electrical equipment, as well as tight fit of the heat-sensitive layer to the controlled elements for reliable registration of the fact of exceeding the threshold temperature throughout the entire service life.

[0084] The control object for this technical solution is electrical equipment elements, in particular, electrical wires with polymer insulation located inside electrical panels. This is due to several reasons. Firstly, the reliability and trouble-free operation of electrical installations is an important and integral factor in ensuring the safety and reliability of almost all types of production, social facilities, transport, urban infrastructure, etc. Secondly, electrical installations are a source of increased fire hazard. Fires due to violations of the rules for the operation of electrical equipment or poor installation rank first after careless handling of fire. Thirdly, in most cases, traditional methods of thermal control, such as thermal imaging inspection in electrical panels, are ineffective due to the complexity of creating a maximum load mode or measuring the load current in each individual wire.However, to reduce the fire hazard of electrical installations, especially in places with a high constant fire load, it is necessary to detect overheating of individual elements of electrical equipment, in particular, electrical wires, at the initial stage of defect development, preventing the occurrence of emergency situations. Thus, the purpose of creating the claimed device was to ensure reliable and reliable registration of overheating of electrical equipment elements, including at facilities with a high fire load.

[0085] The use of a heat-sensitive material based on melting of a heat-sensitive material, accompanied by a change in transparency relative to the initial state when heated to a threshold temperature, ensures: irreversibility of the visual effect of operation; high speed of operation of the device; preservation of the initial state at a temperature slightly lower than the threshold; the required accuracy of the operation temperature, regardless of the time of exposure to temperature.

[0086] The implementation of the base of the temperature-sensitive indicator in the form of a clip also has a number of advantages:

[0087] - allows for simple, reliable and safe installation of a thermal indicator without the use of adhesives, as well as its replacement with electrical panel wires, including in hard-to-reach places of electrical installations, with close proximity of controlled elements of electrical equipment;

[0088] - the thermal indicator layer adheres tightly and evenly to the controlled surface of the electrical equipment;

[0089] - reliable fastening under the influence of the following factors: fluctuations in ambient temperature, mechanical impact, thermal expansion of the material of the controlled element of electrical equipment, etc.

[0090] The factors listed above ensure reliable, safe and accurate operation of the device and registration of the excess of the specified threshold temperature by the controlled elements of electrical equipment throughout the entire service life.

[0091] An information element may be applied to the base, including information about the recorded temperature, for prompt determination during inspections of the numerical value of the threshold temperature recorded by the declared device.

[0092] The front surface of the device and the heat-sensitive material may be covered with an elastic protective film that is transparent to at least part of the visible light, which additionally protects the heat-sensitive material and the clip itself from external environmental influences, humidity, UV radiation and mechanical damage, increases the service life of the device and prevents the heat-sensitive material from flowing during the phase transition.

[0093] Also, to prevent the melted heat-sensitive material from flowing down during the phase transition, which may cause abnormal and emergency situations, a recess may be made in the material from which the base of the device is made to fill it with heat-sensitive material.

[0094] In a preferred embodiment, the device has dielectric properties, preferably having an electric strength of at least 5 kV / mm. The material of the base and the protective film is preferably selected in such a way as to ensure the simultaneous fulfillment of the following criteria:

[0095] - elasticity, flexibility and resilience required for tight adherence of the device to the surfaces of controlled elements of electrical equipment, which often have complex geometry, while maintaining the ability to register overheating with the stated accuracy;

[0096] - ensuring the necessary pressure and fixation of the clip for reliable fixation of the device while maintaining a tight fit, including during vibration, under the influence of various environmental factors, mechanical impact, thermal expansion of the material of the controlled element of electrical equipment; ensuring the necessary adhesion to the protective film and heat-sensitive material;

[0097] - resistance to ignition and self-extinguishing ability in case of exposure to open flame. Ignition of the device, in turn, can lead to a fire in the electrical installation or the occurrence of an electric arc;

[0098] - thermal conductivity sufficient to ensure rapid heating of the device and the heat-sensitive layer to the threshold temperature for reliable and accurate recording of short-term overheating, as well as heat removal from heating wires and contact connections;

[0099] - low electrical conductivity, allowing the device to be installed not only on electrical equipment elements covered with insulating materials, but also on contact connections without insulation. High electrical strength and dielectric properties of the device as a whole are necessary to ensure safe use in electrical installations, engines or various electrical mechanisms. The absence of conductivity and high breakdown voltage prevent failure of electrical circuits, short circuits or ignition of an electric arc when the clip comes into contact with exposed conductive elements;

[0100] - maintaining the original shape when heated, i.e. the base and protective film materials should not melt to their current state when heated to high temperatures, in order to avoid separation of the clip from the wire, softened material flowing down and getting onto electrical equipment components.

[0101] - ensuring stable attachment to the controlled element in a wide temperature range (decomposition temperature is preferably above 150 °C). The most suitable materials for this purpose are halogen-containing polymers, primarily polyvinyl chloride. Polymer materials in the structure of which halogen atoms are present have some of the highest flexibility and elasticity indices among known polymers. The introduction of halogen atoms into the monomers used as the starting material for polymerization disrupts their symmetry and creates many chiral centers in the polymer. Polymerization or polycondensation of such monomers both with each other and with other halogen-containing or halogen-free monomers leads to the formation of polymer chains with a large number of stereocenters.Regular polymers obtained from non-halogenated monomers without chiral centers tend to form crystalline structures, which reduces their elasticity, while a large number of diastereomers arising during halogenation of monomers impart stereochemical disorder to halogen-containing polymers, which prevents crystallization. Thus, halogen-containing polymeric materials have high elasticity and flexibility due to the features of the chemical structure caused by the presence of halogen atoms in the polymer structure. In addition, halogen-containing materials have good adhesion and low flammability, which serves as an additional guarantee of operational safety of the declared device and electrical equipment on which it is located.

[0102] Based on this, in preferred embodiments, the base of the device, made in the form of a clip, is elastic and flexible and includes halogen-containing polymers, predominantly containing the structural unit - CH2CHCI-, predominantly polyvinyl chloride, predominantly cast polyvinyl chloride.

[0103] An elastic protective film, transparent to at least part of the visible light, which can cover the front surface of the device, in particular the heat-sensitive material, is also preferably made of polyvinyl chloride, most preferably cast polyvinyl chloride.

[0104] The elastic protective film can be attached to the base by fusing (welding), glue or other methods.

[0105] In particular embodiments of the technical solution for ensuring the self-extinguishing properties of the base of the device when exposed to an open flame, the base material or the coating of the clip may also include a plurality of hermetically sealed pores filled with a fire extinguishing agent or fire retardant capable of being released from these pores in repeated fire-extinguishing cycles and suppressing the resulting fire.

[0106] Preferably, the base of the device can be made in the form of a single structure with the possibility of fixing on electrical wires, preferably with a diameter of 1 to 10 mm, without additional elements, and special elements for snapping the device onto electrical wires, preferably with a diameter of 1 to 10 mm, can also be made on the base, which ensures ease of installation and additionally increases the reliability of fastening the device to elements of electrical equipment.

[0107] In preferred embodiments, the heat-sensitive material irreversibly changes transparency when heated in a range not exceeding 5 °C, preferably not exceeding 2 °C, relative to the threshold temperature indicated on the device.

[0108] In some versions, the base in the area of ​​the heat-sensitive material is painted black, and when the threshold temperature is reached with the stated accuracy, a visual color transition of the corresponding part of the surface of the device from white to black occurs, that is, the heat-sensitive material in an opaque state is white.

[0109] In particular cases, the heat-sensitive material in its initial state has a microstructure that includes a solid phase and voids that form a continuous gas phase, the proportion of which is not less than 50 vol.%, and is designed with the ability to irreversibly change its appearance upon reaching the specified threshold temperature due to the destruction of the microstructure of the heat-sensitive material, accompanied by the fusion of particles of solid organic matter, a decrease in the proportion of voids and an increase in its transparency with the manifestation of the color of the base (see Fig. 4).

[0110] The use of a heat-sensitive material with voids allows to increase the service life, additionally increase the reliability of overheating detection due to the impossibility of aggregation of solid particles through the gas phase and eliminate the possibility of the material returning to its original state after operation due to an irreversible change in the microstructure, which also has a positive effect on the safety of both the clip and the equipment itself. When melting a heat-sensitive material containing voids, an irreversible change in the original microstructure of the material occurs with a decrease in the proportion of voids in it, associated with the fusion of particles of solid organic matter and with a decrease in the area of ​​the solid-gas phase boundaries due to the irreversible release of gas contained in the voids to the surface and stratification of the gas and non-gaseous environments.As a result, upon further cooling, the solid organic substance crystallizes without voids, thereby irreversibly changing the transparency (increasing relative to the initial state) of the material for at least part of the visible light, creating a visual effect of changing the appearance of the device with high contrast, which ensures high reliability of recording the excess of temperature above the specified value. Preferably, the proportion of voids of the heat-sensitive material after heating above the corresponding threshold temperature value decreases by at least 2 times relative to the initial state, which additionally increases the contrast of the color transition of the device when the threshold temperature value is exceeded.

[0111] The organic substance of the solid phase of the heat-sensitive material can be selected from the group: fatty aliphatic acids containing structural fragments C nH(2n+i) with n>12; salts of fatty aliphatic acids containing structural fragments C n H(2n+i) with n>5; alkanes containing at least 20 carbon atoms; dialkylphosphinic acids containing structural fragments C n H(2n+i) with n>5; fatty acid amides containing structural fragments C n H(2n+i) with n>5; fatty acid anhydrides containing structural fragments C n H(2n+i) with n>10; fatty aliphatic alcohols containing structural fragments C n H(2n+i) with n>14; fatty aliphatic amines containing structural fragments C n H(2n+i) with n>17; nitriles of fatty aliphatic acids containing structural fragments C n H(2n+i) with n>19.

[0112] The use of organic compounds containing one or more aliphatic hydrocarbon chains C as the organic substance of the solid phase of the heat-sensitive material nH(2n+i) with n>5, promotes the formation of a crystalline packing in which the elongated structural fragments of linear hydrocarbons are oriented parallel to each other (A.I. Kitaygorodsky, Molecular Crystals, Moscow: Nauka, 1971). Due to the fact that the particles of solid organic matter are formed in the form of fibers, scales or flat or elongated crystals, i.e. have a two-dimensional structure, the heat-sensitive material forms a special microstructure capable of bending and stretching without deformation and loss of functional properties.

[0113] Also, the use of solid organic compounds, which include non-polar aliphatic fragments, additionally contributes to an increase in the electrical strength values ​​of the device as a whole, since such fatty aliphatic derivatives have good dielectric properties.

[0114] In particular cases, the organic substance of the solid phase of the heat-sensitive material is selected from the group: palmitic acid, stearic acid, behenic acid, tetracosane, erucamide, stearyl alcohol, cetyl alcohol, polyethylene, wax, paraffin, salts of saturated fatty carboxylic acids of rare earth metals, in particular lanthanum, yttrium, ytterbium, scandium.

[0115] In special cases, the microstructure of the heat-sensitive material additionally contains a polymer binder that is transparent at least for part of the visible light, the phase transition temperature of which is higher than the phase transition temperature of the solid organic substance. In this case, the heat-sensitive material contains "solid-transparent solid-gas" phase boundaries; during melting, an irreversible change in the microstructure of the material also occurs, as a result of which the number of voids decreases relative to the initial state due to the release of the gas contained in them onto the surface of the material and stratification of the gas and non-gaseous environments occurs, as a result of which a decrease in the contact area of ​​the solid phase and voids is observed, i.e. a decrease in the area of ​​the phase boundaries.

[0116] Preferably, the polymer binder is present in the heat-sensitive material in an amount of 1-30 wt.%. In particular cases, the polymer binder covers each individual structural particle of the solid organic substance, ensuring its "glazing". The binder is selected in such a way as to ensure wettability, but not dissolution, of the particles of the solid organic substance in the polymer binder. Due to this, when "glazing" grains, crystals, fibers, flakes or conglomerates of said particles, additional gas capture occurs, in the medium of which the heat-sensitive material is formed, and its distribution between the particles of the solid organic substance "glazed" by the binder. In preferred embodiments, the heat-sensitive material is designed with the possibility of changing transparency when heated to a temperature exceeding the threshold, for no more than 5 seconds, preferably no more than 2 seconds.This is due to the fact that the thickness of the layer of heat-sensitive material and its structure in combination with the thickness of the base of the device are selected in such a way as to allow heating the heat-sensitive material when short-term overheating occurs during the peak load period and completely transfer it to a melt with a color transition of "opaque-transparent" for no more than 5 seconds, preferably no more than 2 seconds, and also ensures the necessary heat transfer during air cooling of operating devices. In particular, the thickness of the base in the zone of heat-sensitive material is no more than 3 mm, preferably no more than 1 mm.

[0117] The threshold temperature can be selected from the range of 50-210 °C, preferably 50 °C, 55 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C. Based on the threshold temperature value selected for registration, the applied heat-sensitive material is selected in such a way that the solid organic substance included in its composition has a melting point that differs from the threshold temperature by no more than 5 °C.

[0118] To simplify the visual recording of the threshold temperature being exceeded, the surface area of ​​the base covered with the heat-sensitive material is preferably at least 3 mm 2 , preferably not less than 10 mm 2 .

[0119] In particular embodiments of the device, an information element may be applied to the base, which includes information for marking the elements of electrical equipment or color marking of phases. In particular, the information element applied to the front surface of its base may contain an inscription containing color, letter, digital or alphanumeric marking information. In one case, the information element on the base contains information about the end date of the device's service life. The base may also have a color corresponding to the established rules for marking elements of electrical equipment. The above-listed features serve to impart to the device for recording the excess of the threshold temperature the properties of elements of electrical equipment marking, which also additionally ensures the safety of the operation of the equipment on which such devices are located, due to the following.In the case of contact connections, wires or electrical equipment units, we are talking about small surfaces that require marking on the one hand and temperature monitoring on the other. However, it is often not possible to use marking devices and temperature detection devices separately due to insufficient space on the controlled surface. Using only a temperature indication device without marking can lead to incorrect identification of the defective unit, as well as to an increase in the detection time. Thus, a device that combines the properties of a marking device and the properties of temperature indicators will have a positive effect on the safety of electrical equipment operation.

[0120] In order to increase the visibility of both the device itself and the fact of its operation, on equipment elements, including those difficult to inspect due to the large size of the installations, the location of the installations outdoors or due to the inspection being carried out in bad weather conditions and in conditions of insufficient visibility, at night using a flashlight, as well as for inspecting equipment without artificial lighting and windows, and, as a consequence, to further increase the safety of equipment operation, the base may have reflective properties or may be painted using a substance that has luminescent properties.Ensuring visibility, as well as the reliability of detection of local heating of electrical equipment elements, is achieved using a version of the device with a surface area of ​​the base covered with a heat-sensitive material, from 3 to 97% of the area of ​​the front surface of the base, preferably not less than 30% of the area of ​​the front surface of the base.

[0121] In special cases, the base may be colored using a substance that is capable of irreversibly changing color when heated.

[0122] The use of substances in the base painting that are capable of irreversibly changing color when heated to a temperature lower than the threshold temperature of the main heat-sensitive material, for example, by 10-30 °C, allows informing personnel about the risk of an emergency defect occurring in the future, and thus ensures the possibility of preventing it, with due response from the personnel responsible for this equipment. Thus, the operation of such a substance, in the absence of the operation of the main heat-sensitive material, indicates the presence of overheating of the equipment that has not reached the maximum permissible values ​​corresponding to the threshold temperature of the main heat-sensitive material, and the need to inspect it in order to identify and eliminate malfunctions that could subsequently lead to the development of an emergency defect.Thus, the presence of a substance capable of irreversibly changing color when heated to a temperature below the threshold temperature of the main heat-sensitive material, in particular by 10-30 °C, additionally increases the safety of operation of both the declared device and the equipment as a whole.

[0123] Also, the base or some part of it can be painted using a substance designed to reversibly change color when heated. For example, a layer of heat-sensitive paint with the above-mentioned properties can be applied to the front surface.

[0124] The presence of a substance capable of reversibly changing color when heated allows informing personnel not only about exceeding the temperature threshold in the past, but also about overheating at the time of inspection. The activation of such a substance at the time of inspection indicates that the equipment is in emergency mode at the current moment and may be a source of increased danger. Thus, the presence of a substance capable of reversibly changing color when heated additionally increases the safety of operation of both the declared device and the equipment as a whole.

[0125] Brief description of the drawings

[0126] The technical solution will be more understandable from the description, which is not limiting in nature and is given with references to the attached drawings, which show:

[0127] Fig. 1 - Device for recording the excess of a threshold temperature, made in the form of a clip with additional fastening elements, with a recess in the base material filled with a heat-sensitive material, and with additional coloring in the area of ​​the heat-sensitive material (top view in section).

[0128] Fig. 2 - Front view of a device for recording an excess of a threshold temperature, made in the form of a clip, the base of which has luminescent properties, with additional coloring in the area of ​​the heat-sensitive material and an information element including a numerical value of the threshold temperature and located under the heat-sensitive material: 2a - initial view of the device, 2b - the device that has been triggered after the threshold temperature has been exceeded, 2c - view of the device after further cooling to room temperature.

[0129] Fig. 3 - Three-dimensional model of a device for recording an excess of a threshold temperature, made in the form of a clip with additional fastening elements and an information element including a numerical value of the threshold temperature and a heat-sensitive material located nearby.

[0130] Fig. 4 - Device for recording the excess of a threshold temperature, made in the form of a clip with additional fastening elements, additional coloring in the area of ​​the heat-sensitive material and a protective film covering the heat-sensitive material (top view in section).

[0131] Fig. 5 - Three-dimensional model of a device for recording the excess of a threshold temperature, made in the form of a clip with additional fastening elements, the base of which is painted in the colors of the phase markings.

[0132] Fig. 6 - Microstructure of a heat-sensitive material with particles of organic matter in the form of scales and their conglomerates, a binder and voids before activation (a) and after activation (6).

[0133] Fig. 7 - Front view of a device for recording an excess of a threshold temperature, made in the form of a clip: (a) - initial view of the device, (6) - partially activated device after point heating of the controlled surface above the threshold temperature value with a change in the transparency of only that area of ​​the heat-sensitive material that was subject to heating above the threshold temperature, while maintaining an opaque area of ​​this material in its remaining zone that was not subject to heating.

[0134] Fig. 8 - Layered structure of a device for recording an excess of a threshold temperature, made in the form of a clip, in the area of ​​a heat-sensitive material: (a) - with a sealed transparent protective layer, (6) - with a transparent protective layer in which a gap is made between the protective layer and the base, (b) - with a transparent protective layer in which micro-holes are made.

[0135] Fig. 1 shows a cross-section of a device for recording an excess of a threshold temperature, which is an opaque base 1, made in the form of a clip, containing additional fastening elements 6. On the front side of the base material there is a recess filled with a heat-sensitive material 2. Fig. 1 shows a particular version of the device, in which the base 1 is yellow for marking the phases of electrical equipment and is painted black 3 in the area of ​​the heat-sensitive material.

[0136] Fig. 2 shows the front side of the device for recording the excess of the threshold temperature, which is an opaque base 1, made in the form of a clip and possessing luminescent properties, and a heat-sensitive material 2 applied to its front side: in the initial state before heating (a), after heating to the threshold temperature of the heat-sensitive material (b) and after further cooling to room temperature (c). Fig. 2 shows a particular version of the device with an information element 4, including the numerical value of the threshold temperature and located under the heat-sensitive material, the base 1 is painted black in the zone of the heat-sensitive material.

[0137] Fig. 3 shows a three-dimensional model of a device for recording an excess of a threshold temperature, which is an opaque base 1, made in the form of a clip, containing additional fastening elements 6, and a heat-sensitive material 2 applied to its front side. Fig. 3 shows a particular version of the device with an inscription indicating the recorded threshold temperature 4, located on the base next to the heat-sensitive material, and the base 1 is yellow.

[0138] Fig. 4 shows a cross-section of a device for recording an excess of a threshold temperature, which is an opaque base 1, made in the form of a clip, containing additional fastening elements 6, on the front surface of which a heat-sensitive material 2 is applied, covered with a transparent elastic protective layer 5. Fig. 4 shows a particular version of the device, in which the base 1 is yellow and painted black 3 in the area of ​​the heat-sensitive material.

[0139] Fig. 5 shows a three-dimensional model of a device for recording an excess of a threshold temperature, which is an opaque base 1, made in the form of a clip, containing additional fastening elements 6, and a heat-sensitive material 2 applied to its front side. Fig. 5 shows a particular version of the device with a base 1, painted in red, corresponding to the phase marking.

[0140] Fig. 6 shows the microstructure of the heat-sensitive material 2 with particles of organic matter 7 made in the form of scales and their conglomerates, binder 10 and voids 8 before heating (a) and the microstructure of the heat-sensitive material 2 with a reduced proportion of voids 8 and with an increased apparent density and with particles 7 that have undergone fusion and lost their original shape, after heating above the threshold temperature value (b).

[0141] Fig. 7 shows the front side of the device for recording the excess of the threshold temperature, which is an opaque base 1, made in the form of a clip, and a heat-sensitive material 2 applied to its front side: before heating (a) and after spot heating (b) of the controlled surface, as a result of which a change in transparency occurred only in that area 12 of the heat-sensitive material 2, which was subjected to heating above the threshold temperature, while maintaining the original appearance of the rest of the area of ​​the heat-sensitive material 2.

[0142] Fig. 8 shows a layered structure of a device for registering an excess of a threshold temperature, the base 1 of which is made in the form of a clip, onto which a heat-sensitive material 2 is applied, covered with a transparent protective layer 4, which: (a) fits tightly to the base and the material and ensures the tightness of the device and the ability to maintain a pressure below atmospheric; (b) fits tightly to the base and the material and has a gap Ha between the protective layer and the base; (c) fits tightly to the base and the material and has micro-holes 116 on its front surface.

[0143] Implementation of a technical solution

[0144] General technology of manufacturing the device.

[0145] Halogen-containing polymeric materials containing, in particular, vinyl chloride copolymers, namely: copolymer C-15 (copolymer of vinyl chloride and vinyl acetate), copolymer VHVD-40 (copolymer of vinyl chloride and vinylidene chloride), polyvinyl chloride (PVC), cast PVC, as well as polyvinylidene fluoride P VDF, fluoroplastic M-40, as well as polyesters with additives of 6.5% hexabromocyclododecane or polyesters modified with 15% trichloroisopropyl phosphate, can be used as the base 1 of the claimed device. The said materials have the necessary strength and flexibility, impart resistance to combustion to the device and have an electric strength of at least 5 kV / mm.The base 1 is made in the form of a clip, providing simple, safe and convenient installation of the device on electric wires, preferably with a diameter of 1 to 10 mm, or other elements of electrical equipment, made in the form of a single structure with the possibility of fixing on controlled objects without additional elements or including elements 6 for snapping the device onto controlled objects. Further, options for manufacturing and using the claimed device will be considered using the example of a clip without additional elements, the base of which is made of PVC.

[0146] The thickness of the base may be uneven and depends on the design of the clip, however, in the area of ​​the heat-sensitive material, the thickness of the base is preferably no more than 3 mm, most preferably no more than 1 mm, which provides the possibility of changing the transparency of the heat-sensitive material when heated to a temperature exceeding the threshold, for no more than 5 seconds, preferably no more than 2 seconds, which also increases the safety of the operation of the controlled equipment, since it allows heating the heat-sensitive material when short-term overheating occurs during the peak load period and completely converting it into a melt with an “opaque-transparent” color transition and the appearance of the color of the base under it for no more than 5 seconds, preferably no more than 2 seconds, and also provides the necessary heat transfer.

[0147] In some embodiments, the base may have reflective properties or may be painted using a substance with luminescent properties to increase the visibility of both the device itself and the fact of its operation, which serves to further increase the safety of equipment operation. Also, in special cases, the base may be painted to enable the use of the declared clip for color marking of electrical equipment phases.

[0148] In special cases, the base can be painted using a substance made with the ability to irreversibly change color when heated. The presence of an additional substance made with the ability to irreversibly change color when heated to a temperature below the threshold temperature of the main heat-sensitive material, in particular, by 10-30°C, allows detecting overheating of equipment that has not reached the maximum permissible values, and, as a result, ensuring the prevention of an emergency defect.

[0149] Also, the base can be painted using a substance designed to reversibly change color when heated. For example, a layer of heat-sensitive paint with the above-mentioned properties can be applied to the front surface. The presence of a substance designed to reversibly change color when heated allows informing personnel not only about exceeding the temperature threshold in the past, but also about overheating at the time of inspection.

[0150] Halogen-containing polymers, in particular PVC films or polyurethane films modified with 15% trichloroisopropyl phosphate, can also be used as elastic protective films. However, it must be taken into account that if they are used for protective films, they must be transparent to at least part of the visible light.

[0151] Preparation of heat-sensitive material.

[0152] Preferably, the solid phase of the heat-sensitive material comprises an organic substance containing a structural fragment C n H(2n+i), where n > 5: fatty aliphatic acids containing structural fragments C n H(2n+i) with n > 12; salts of fatty aliphatic acids containing structural fragments C n H(2n+i) with n > 5; alkanes containing at least 20 carbon atoms; dialkylphosphinic acids containing structural fragments C n H(2n+i) with n>5; fatty acid amides containing structural fragments C n H(2n+i) with n > 5; fatty acid anhydrides containing structural fragments C n H(2n+i) with n > 10; fatty aliphatic alcohols containing structural fragments C n H(2n+i) with n > 14; fatty aliphatic amines containing structural fragments C n H(2n+i) with n > 17; nitriles of fatty aliphatic acids containing structural fragments C nH(2n+i) with n> 19, for example, palmitic acid, stearic acid, behenic acid, tetracosane, erucamide, stearyl alcohol, cetyl alcohol, polyethylene, wax, paraffin, salts of saturated fatty carboxylic acids of rare earth metals, in particular lanthanum, yttrium, ytterbium, scandium, or a mixture thereof with a melting point differing from the corresponding threshold temperatures indicated on the device by no more than 5 °C, were ground to a size of 2-3 microns in a ball mill, a diluent or a solution of a binder in a diluent were successively added and stirred until a homogeneous mass. For example, water, methanol, ethanol, isopropanol, ethylene glycol, ethylene glycol monomethyl ether, acetonitrile, etc., or mixtures thereof can be used as a diluent. The suspension was used for application immediately after preparation. In preferred embodiments, the content of the solid phase in the heat-sensitive material, including organic matter, is at least 50 mass.%, most preferably not less than 70 wt.%.

[0153] The organic substance is selected in such a way that when the threshold temperature is reached in the range of no more than 5 °C, preferably no more than 2 °C, it melts with a visual transition from opaque to transparent.

[0154] In various embodiments, the substance that causes a change in the transparency of the heat-sensitive material when heated above the threshold temperature and that is part of the heat-sensitive material is selected in such a way that the threshold temperature can be selected from the range from 50 °C to 210 °C, in particular cases, the temperature threshold is selected from the group: 50 °C, 55 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C.

[0155] To produce a heat-sensitive material, the solid phase, including a substance causing a change in the transparency of the heat-sensitive material when heated above the threshold temperature, is ground in a ball mill to a size of 2-3 μm, a liquid phase is successively added, represented by water or an organic solvent with a boiling point of less than 180 °C, and the resulting suspension is stirred, while preferably, during this period, periodic dispersion of the mixture with air access is ensured until a constant density of the mixture is obtained. The liquid phase is preferably water or an organic solvent, the solubility in which of the solid phase of the heat-sensitive material does not exceed 10 g / kg.

[0156] In preferred embodiments of the invention, the liquid phase is added in an amount of from 50 vol.% to 90 vol.%.

[0157] The difference in density between the liquid phase and the solid phase is preferably less than 0.2 g / cm 3For this purpose, the liquid phase can be selected from the group: isopropanol, water, methanol, 1-propanol, isobutanol, ethylene glycol monomethyl ether, 1-butanol, acetonitrile, acetic acid, hexane, heptane, 1,1,1-trifluoroethanol, 1, 1,1, 3,3,3-hexafluoroisopropanol, dimethylformamide, ethanol, butyl acetate, water, acetone, toluene or mixtures thereof, but are not limited to them.

[0158] With this method of production, the obtained heat-sensitive material is preferably represented by two continuous phases: solid and gas. In this case, the solid phase is represented by particles, predominantly oriented parallel to the surface of the base. In this case, the obtained heat-sensitive material in the initial state is opaque for at least part of the visible light and in the initial state includes a solid phase and voids filled with a gas phase, the proportion of which in the initial state is not less than 50 vol.%, and when heated above the corresponding threshold temperature value, an irreversible change in the microstructure of the corresponding heat-sensitive material occurs, accompanied by the fusion of particles of solid organic matter, a decrease in the proportion of voids, preferably by 2 or more times, and an increase in its transparency with the manifestation of the color of the base, and upon subsequent cooling to 20 °C and holding at this temperature for at least one month, preferably one year or more, the transparency of the heat-sensitive material does not return to its original values.

[0159] Depending on the nature of the solid phase and the substance that causes the change in transparency of the heat-sensitive material when heated above the threshold temperature, the type of solid phase particles obtained may be grains, crystals, fibers, flakes, or conglomerates of the said particles.

[0160] In particular cases, the heat-sensitive material additionally contains a polymer binder transparent at least for part of the visible light, the phase transition temperature of which is higher than the phase transition temperature of the organic substance of the solid phase. In this case, the crushed solid phase is suspended in a solution of a binder transparent at least for part of the visible light in the liquid phase. In preferred embodiments of the technical solution, the binder is present in the resulting heat-sensitive material in an amount of 1-30 mass %, to ensure the effect of glazing the particles of the solid organic substance.

[0161] In particular cases, the transparent polymer binder is selected from phenol-formaldehyde resin, butyl methacrylic resin, melamine-formaldehyde resin, polyvinyl butyral, polybutyl methacrylate, polyisobutyl methacrylate, polybutyl acrylate, phenoxy resin, polystyrene-acrylic emulsion, polyolefin, polystyrene, polyacrylate, polyethersulfone, polyethylene, polypropylene, polystyrene, polyvinylidene fluoride, polytetrafluoroethylene, polyethersulfone, polyisoprene, polypropylene, polybutadiene, polyisobutylene, polyvinyl acetate, polymethacrylate, ethyl cellulose, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polycaprolactone, polyethylene terephthalate resin, polybutylene terephthalate resin, polyamide resin, polyvinylidene fluoride, polyester, polyester resins, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, nitrocellulose, carboxymethyl cellulose, gelatin, agar-agar, casein, gum arabic, polyvinyl alcohol, polyethylene oxide or mixtures thereof.

[0162] In some cases, the front side of the device was marked with information about the threshold temperature. In some cases, in addition to the threshold temperature, information about the end of the service life was also marked. In one version, a drawing intended for marking the phases or units of electrical equipment containing graphic, numerical or text information can be marked on the surface of the base.

[0163] In general, the process of manufacturing the device includes the stages of applying one or more layers of a suspension of solid phase particles in a liquid phase to individual sections of an opaque base, removing the liquid phase from the applied layers of suspension, and covering the front surface of the workpiece with a transparent protective layer.

[0164] In order to obtain a microstructure of the applied heat-sensitive material, including a solid phase and voids filled with a gas phase, the proportion of which in the initial state is not less than 50 vol.%, and ensuring an irreversible change in appearance upon reaching the threshold temperature, which is accompanied by melting of the solid phase particles, a decrease in the proportion of voids and an increase in its transparency with the manifestation of the color of the base, it is possible to use, in particular, the following techniques at the previously disclosed stages of the method:

[0165] - at least one of the above-mentioned stages of the method (applying a suspension of particles of a solid organic substance in the liquid phase, removing the liquid phase from the applied layers of the suspension, covering the front surface of the workpiece with a transparent protective layer) is carried out at a pressure below atmospheric.

[0166] - at least 3 cycles of applying layers of a suspension of solid phase particles in a liquid phase and removing the liquid phase from the applied layers of this suspension are carried out, wherein the application of the suspension of solid phase particles in the liquid phase is carried out by a method selected from the group: screen printing, flexographic printing, pad printing, silk-screen printing, with the production of a microstructure of a heat-sensitive material, the particles of the solid phase in which are oriented predominantly parallel to the plane of the base surface.

[0167] The removal of the liquid phase from the applied layers of suspension of solid phase particles in the liquid phase or from each layer separately can be carried out either at a pressure below atmospheric pressure or at atmospheric pressure, depending on the selected method of manufacturing the device.

[0168] Subatmospheric pressure, in particular cases of obtaining the device, can be used both immediately after the application of each individual layer of the suspension of solid organic matter in the liquid phase, and at the stage of drying (i.e., removing the liquid phase) of the required number of applied layers of the suspension of solid organic matter in the liquid phase. In this case, spontaneous release of the liquid phase from the volume of the material (sequentially from each layer or from the entire volume of the material) occurs with the formation of a larger number of unstructured voids.

[0169] Layer-by-layer application of a solid phase suspension in a liquid phase can also ensure the production of the claimed device. In this case, after application of the heat-sensitive material, the device is dried by selecting the mode of removing the liquid phase from the applied layers of the suspension, preferably at a temperature of (20±2) °C for 10 minutes in an air atmosphere, then the layer-by-layer application procedure is repeated until the required coating thickness is obtained. The formation of a microstructure including solid phase particles and a large proportion of voids filled with a gas phase occurs layer by layer. Layer-by-layer application with holding preferably at room temperature between approaches ensures the orderliness of the solid phase particles when they are located on the device and the formation of a large proportion of voids, which predominantly form a continuous gas phase.In case the solid phase particles are flakes, in order to achieve covering power with minimum layer thickness it is preferable to arrange them longitudinally “overlapping” on the basis of the temperature indicator. In this case the flakes will be arranged like closed blinds and a thin layer of flakes will be sufficient to cover the base color (“closed blinds principle”). Due to the spontaneous removal of the liquid phase from the applied layers of suspension at room temperature, slow settling of the flakes and their packing in a thermodynamically favorable state is ensured. When using the specified method in the preparation of heat-sensitive material, the predominant formation of a continuous solid phase is observed, and the voids filled with gas, in this case, form a continuous gas phase.When carrying out forced removal of the liquid phase from the applied layers of suspension by heating or by blowing air, the kinetic processes of solvent evaporation will prevail over the thermodynamic ordering of the particles of the solid phase, as a result of which the flakes will form not longitudinal, but transverse structures (“the principle of open blinds”), through which the base will be visible at the same layer thickness for which, when observing the principle of closed blinds, hiding power will be achieved.

[0170] Such ordering can also be achieved by using a dilute suspension of solid phase particles in the liquid phase (dilution of more than 50%), since the orientation of the flakes in the desired manner and their sedimentation in an ordered form will occur in a large volume, in contrast to the use of more concentrated suspensions. In addition, a large dilution guarantees a longer process of spontaneous evaporation of the liquid phase, during which the flakes will also be laid down according to the principle of closed blinds. Another factor affecting the rate and nature of sedimentation of solid phase particles is the relative difference in densities of the solvent and solid phase particles. In the presence of a large difference in densities (more than 0.2 g / cm 3 ) the solid phase particles will settle out of the suspension too quickly according to the principle of open blinds. At comparable densities or at a density difference of less than 0.2 g / cm 3a slow settling of solid phase particles will be observed, with the formation of the necessary ordered microstructure of the material and compliance with the principle of closed blinds.

[0171] Thus, adherence to the principle of closed blinds when forming the microstructure of a heat-sensitive material makes it possible to obtain a material whose microstructure in the initial state has a preferential orientation of solid phase particles parallel to the surface of the base and protective coating.

[0172] The application of layers of a solid phase suspension in a liquid phase is preferably carried out by a method selected from screen printing, flexographic printing, pad printing, silk-screen printing.

[0173] The effects described above are applicable to device designs in which the microstructure of the heat-sensitive material is represented by an organic substance, the particles of which are predominantly in the form of scales, crystals or fibers, i.e. particles whose linear dimensions exceed their thickness. In this case, the formation of intergrowths (conglomerates) of individual particles (scales, crystals or fibers) of solid organic matter can be observed.

[0174] In the case of using a heat-sensitive material containing a solid phase, a binder and voids, a suspension of a finely dispersed solid phase in a binder solution in the liquid phase is used to prepare the heat-sensitive material. When the liquid phase evaporates, the binder settles on the particles of the solid phase, covering their surface with a thin, uniform layer. This results in “glazing” of both an individual particle of the solid phase and the resulting conglomerate of particles.

[0175] When applying a suspension of solid phase particles in a liquid phase, the area of ​​the front surface of the device base, which should not be exposed to heat-sensitive material, is sealed with polyethylene film. A layer of suspension of solid phase particles in a liquid phase is uniformly applied to the uncovered area of ​​the base using one of the above-described techniques or other methods that ensure the formation of the described microstructure.

[0176] In preferred embodiments, the thickness of the heat-sensitive material layer is no more than 800 μm, preferably no more than 450 μm, most preferably no more than 150 μm. The use of the specified thickness of the heat-sensitive material layer ensures its response at a speed of less than 5 seconds, preferably less than 2 seconds, when heated above the threshold temperature. This is due to the fact that such a thickness of the material layer in combination with the thickness of the base of the temperature indicator allows heating the heat-sensitive material when short-term overheating occurs during the peak load period and completely converting it into a melt with an "opaque-transparent" color transition in less than 5 seconds, and also ensures the necessary heat transfer during air cooling of the operating devices.

[0177] The area of ​​the front surface of the base is from 3 mm 2 , preferably not less than 10 mm 2, and the surface area of ​​the base covered with the heat-sensitive material is from 3 to 97% of the area of ​​the front surface of the base, preferably not less than 30% of the area of ​​the front surface of the base, which makes it possible to detect triggered devices from a long distance, and also makes it possible to detect point heating of a large surface of the installations.

[0178] In some embodiments of the technical solution, black paint or an inscription including, in particular, a numerical value of the threshold temperature or other graphic, numerical or textual information is first applied to the uncovered area of ​​the base using solvent dyes, and then a layer of heat-sensitive material is applied. In this case, in the preferred embodiments of the invention, at least 70% of the area of ​​the base is covered with black paint. In the case of painting at least part of the base black, the heat-sensitive material in the initial state is white, and when heated above the threshold temperature, a visual color transition of at least part of the surface of the device “white-black” occurs.

[0179] It should be noted that the claimed technical solution is not limited to the use of only one heat-sensitive material, and if necessary, the temperature indicator can be supplemented with various heat-sensitive materials to determine the excess of several threshold temperatures.

[0180] At the final stage of preparation, the temperature indicator was covered with a transparent protective layer. In some versions of the technical solution, a gap can be made between the protective layer and the base, or micro-holes can be made in the transparent protective layer, allowing the gas phase to go beyond the device after exceeding the registered temperature. Preferably, the transparent protective layer is selected from transparent elastic polymers. In another version of the technical solution, the device blank is maintained at a pressure below atmospheric pressure and then covered with a transparent protective layer, ensuring the tightness of the device and maintaining the pressure inside the voids with the gas phase below atmospheric pressure. For this purpose, in this version of the technical solution, transparent elastic polymer films are also used as a protective layer.

[0181] In certain cases, a recess can be made in the base material of the clip, which is filled with a heat-sensitive material using the methods indicated above.

[0182] In preferred embodiments, the heat-sensitive material is designed to register local overheating of the surface by changing the color of only that part of the heat-sensitive material that was heated above the threshold temperature and maintaining the original color of the heat-sensitive material that was not heated above the threshold temperature, during uneven heating.

[0183] After applying the heat-sensitive material, the device is covered with an elastic protective film that is transparent at least to part of the visible light, which protects the device from external environmental influences, humidity, UV radiation and mechanical damage, increases the service life of the device and does not allow the heat-sensitive material to flow during the phase transition. Thus, the device is designed with the ability to register the excess of the threshold temperature of the conductive elements in the open air.

[0184] In a particular case, the elastic base 1 can be colored to perform additional marking of cable phases, installation wires, harnesses and other elements of electrical equipment, and the color of the base is selected in accordance with GOST 28763-90, which establishes, in particular, color marking in the field of electrical engineering. The color of the elastic base 1 does not affect the visual registration of exceeding the threshold temperatures of the equipment surface, but provides for the marking of the device, which is necessary to improve the overall safety of equipment operation.

[0185] Also, in a particular case, a dye, including black, can be applied to the flexible base, in the area of ​​the heat-sensitive material, before applying the heat-sensitive material. In one embodiment, at least 70% of the base area covered with the heat-sensitive material is painted black.

[0186] The principle of operation of the device.

[0187] A clip, including a base 1 and a heat-sensitive material 2 applied to it and a transparent protective layer 5, is installed on the surface of an electric wire, behind which temperature control must be ensured, with a tight fit of the device, using fastening elements 6 provided by the design of the clip. In another embodiment, the clip is attached to the surface of the electric wire without additional fastening elements due to the elastic properties of the base material. Regardless of the fastening of the clip, the operating principle does not change.

[0188] The clip for registering the excess of the threshold temperature with the applied heat-sensitive material operates as follows. The applied heat-sensitive material 2 in the initial state and until the moment of heating to the threshold temperature is opaque for at least part of the visible light and, in the preferred variants of the technical solution, is white. Until the moment of heating the entire surface of the clip or its individual sections located under the heat-sensitive material 2 to the threshold temperature value, the heat-sensitive material 2 remains opaque for at least part of the visible light, thereby preserving the original appearance of the clip.When the surface is heated above the threshold temperature of the heat-sensitive material 2, irreversible destruction of the microstructure of the heat-sensitive material 1 occurs on the entire surface of the heat-sensitive material 2 or predominantly on the heated section 12 of the heat-sensitive material 2, respectively, accompanied by the fusion of solid phase particles 7, a decrease in the proportion of voids 8 and, as a consequence, an increase in transparency. In this case, an increase in the apparent density of the material occurs. The heat-sensitive material 2 with a modified microstructure is transparent and reveals the color of the base 1 under this material or the color of the paint 3 applied to the base in the area of ​​the heat-sensitive material. Upon subsequent cooling of the controlled surface, the heat-sensitive material 2 or its part 12 remains transparent and the appearance of the temperature indicator does not return to its original state.This ensures the possibility of visually registering the temperature exceeding the threshold temperature value, both at the moment of overheating and after a long period of time.

[0189] When the controlled surface is heated locally, the transparent zone 12 is formed only in that area of ​​the heat-sensitive material that was subjected to heating above the threshold temperature, while maintaining an opaque area of ​​the given material in its remaining area that was not subjected to heating.

[0190] The numerical value of the threshold temperature 4 can be applied to the front side of the base 1, in particular cases the threshold temperature value can be applied in the zone free from the heat-sensitive material 2, but next to it, or to the base 1 under the heat-sensitive material 2, in the latter case, when the temperature exceeds the threshold value, after an irreversible change in the microstructure of the heat-sensitive material 2, the color of the base 1 and the numerical value of the threshold temperature 4 appear. In particular embodiments, the base can be black, and the heat-sensitive material in its original opaque state can be white. In this case, after the temperature exceeds the threshold value, a change in the appearance of the thermal indicator is observed with a maximum contrast of “white-black”, which additionally ensures the visibility of the triggered thermal indicator and facilitates its visual detection.A similar purpose is served by the implementation of a thermal indicator, in which the base has a color different from black, and in the area under the heat-sensitive material 2, which is white in its initial state, black paint is applied. In this case, when the thermal indicator is triggered, a “white-black” color transition is also observed.

[0191] In the case of a temperature indicator hermetically covered with an elastic transparent protective layer 5 at atmospheric pressure, at the moment of operation, as a result of the destruction of the microstructure of the heat-sensitive material 2 and the stratification of the gas and non-gas environments, a bubble will form on the surface of the protective layer 5, which decreases when the device cools. When using a temperature indicator with a hermetically sealed protective layer 5 and a pressure inside the voids 8 of the heat-sensitive material 2 below atmospheric, no bubble will be formed on the surface of the protective layer 5 when the threshold temperature is exceeded, due to the fact that the pressure of the gas phase inside the voids 8 below atmospheric in the initial state, created at the stage of obtaining the temperature indicator blank when applying the protective layer 5, compensates for the thermal expansion of the gas released when the microstructure of the heat-sensitive material 2 is destroyed.In other embodiments of the temperature indicator, in order to prevent the formation of a bubble when the threshold temperature is exceeded, a gap 11a can be made between the transparent protective layer and the base, or micro-holes 116 can be made in the protective layer, allowing the gas released during operation to escape.

[0192] The clip design variants in which the heat-sensitive material 2 includes solid phase particles 7, voids 8 and a binder 10 have a similar operating principle. When the temperature exceeds the threshold value, the particles 7, “glazed” with a binder 10, fuse, releasing the gas phase and separating the gas and non-gaseous environments, which also results in irreversible destruction of the microstructure of the heat-sensitive material 2, accompanied by a decrease in the proportion of voids 8 and, as a consequence, an increase in the transparency of the material.

[0193] Thus, all versions of the temperature indicator have a principle of operation based on the irreversible destruction of the microstructure of the temperature-sensitive material 2, accompanied by the fusion of solid phase particles 7, a decrease in the proportion of voids 8 and, as a consequence, an increase in the transparency of the material and an irreversible change in the appearance of the temperature indicator. Moreover, when the temperature indicator is cooled, the appearance does not return to its original state, mainly a decrease in the transparency of the temperature-sensitive material to its original values ​​does not occur when cooling to 20 °C and maintaining at this temperature for at least one month, preferably one year or more.

[0194] Thus, during a visual inspection of the temperature indicator, the fact that the temperature of the entire surface or its local area has exceeded the threshold value can be reliably and with high accuracy (in the range of + / - 5 °C, preferably + / - 2 °C, relative to the threshold temperature indicated on the temperature indicator) and speed (no more than 5 seconds, preferably no more than 2 seconds).

[0195] Below are presented preferred embodiments of the claimed temperature indicator, which are illustrative and in no way limit the scope of the requested legal protection.

[0196] Examples

[0197] Example 1. General technology of manufacturing the device

[0198] Preparation of the heat-sensitive material: 100 g of an organic substance with a phase transition temperature corresponding to the threshold registration temperature in the range of 5 °C was ground to a size of 2-3 microns, 300 g of a 3-33% solution of a binder in water, methanol, ethanol, isopropanol, ethylene glycol, ethylene glycol monomethyl ether, acetonitrile or their mixtures were successively added and stirred until a homogeneous mass. The suspension was immediately used for applying the composition.

[0199] For the examples, as one of the possible design options for the device, halogen-containing polymer bases of various colors were chosen, which are resistant to combustion and have an electrical strength of at least 5 kV / mm, as well as elasticity, allowing them to be placed on electrical wires, preferably with a diameter of 1 to 10 mm without additional fastening elements.

[0200] An information element containing the threshold response temperature in degrees Celsius was applied to the base made in the form of a clip using solvent dyes. The heat-sensitive material was applied using silk-screen printing in 5-7 layers. Between applications, the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for at least one hour, or in a thermostat at a temperature no higher than the response temperature of the composition for at least three hours, or for 24 hours at room temperature. In its initial state, the heat-sensitive material is white. The device was covered with a transparent elastic protective film.

[0201] Example 2. Tetracosane with a phase transition temperature of 50 °C was used as the organic substance for preparing the heat-sensitive material according to Example 1, polycaprolactone was used as a binder, and methanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, having a thickness in the area of ​​the heat-sensitive material of 0.5 mm, according to the method described in Example 1, wherein the numerical value of the threshold temperature was applied in the zone free of the heat-sensitive material. The number of layers of the heat-sensitive material was 7, between applications the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for one hour. The thickness of the layer of heat-sensitive material was 0.6 mm, and its area was 30% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.05 mm thick.

[0202] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 50 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 2 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0203] Example 3.

[0204] Ytterbium caprylate with a phase transition temperature of 60 °C was used as the organic substance for preparing the heat-sensitive material according to Example 1, polyvinyl butyral was used as the binder, and a mixture of methanol with ethylene glycol methyl ether (50 / 50 vol.%) was used as the solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip with additional fastening elements made of red M-40 fluoroplastic, having a thickness in the area of ​​the heat-sensitive material of 0.7 mm, according to the method described in Example 1, wherein the numerical value of the threshold temperature was applied in the area of ​​the heat-sensitive material before its application, and information on the service life was applied in the area free of the heat-sensitive material. The number of layers of the heat-sensitive material was 7, between applications the composition was dried in a thermostat at a temperature of 40 °C for three hours.The thickness of the heat-sensitive material layer was 0.8 mm, and its area was 97% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.15 mm thick.

[0205] The clip was installed at room temperature on a cylindrical heating element with a diameter of 5 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 60 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 4 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0206] Example 4.

[0207] Eicosanoic acid with a phase transition temperature of 70 °C was used as an organic substance for preparing the heat-sensitive material according to Example 1, melamine-formaldehyde resin was used as a binder, and a mixture of methanol and isobutanol (90 / 10 vol.%) was used as a solvent. The suspension was applied by silk-screen printing onto a base made in the form of a clip without additional fastening elements made of a red vinyl chloride and vinyl acetate copolymer, having a thickness in the area of ​​the heat-sensitive material of 0.2 mm, according to the method described in Example 1, wherein a numerical value of the threshold temperature, as well as black paint, were applied in the area of ​​the heat-sensitive material before its application. The number of layers of the heat-sensitive material was 5, between applications the composition was dried for 24 hours at room temperature. The thickness of the layer of the heat-sensitive material was 0.2 mm, and its area was 70% of the area of ​​the front surface of the device.The device was covered with a transparent protective film made of polyurethane modified with 15% trichloroisopropyl phosphate, 0.15 mm thick. The device was glued at room temperature to a cylindrical heating element with a diameter of 10 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 70 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition and the change in the transparency of the heat-sensitive material occurred was 1 second. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0208] Example 5.

[0209] Dioctylphosphinic acid with a phase transition temperature of 80 °C was used as an organic substance for preparing the heat-sensitive material according to Example 1, polyvinyl butyral was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of a copolymer of vinyl chloride and vinylidene chloride, green in color with light-reflecting properties, having a thickness in the area of ​​the heat-sensitive material of 0.35 mm, according to the method described in Example 1, wherein a numerical value of the threshold temperature, as well as black paint, were applied in the area of ​​the heat-sensitive material before its application. The number of layers of the heat-sensitive material was 5, between applications the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for one hour. The thickness of the layer of the heat-sensitive material was 0.4 mm, and its area was 3% of the area of ​​the front surface of the device.The device was covered with a transparent protective film made of PVC, 0.15 mm thick.

[0210] The clip was installed at room temperature on a cylindrical heating element with a diameter of 12 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 80 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 2 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0211] Example 6.

[0212] Yttrium behenate with a phase transition temperature of 90 °C was used as an organic substance for preparing the heat-sensitive material according to Example 1, polybutyl methacrylate was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing onto a base made in the form of a clip without additional fastening elements made of polyvinylidene fluoride, painted with orange paint with luminescent properties, having a thickness in the area of ​​the heat-sensitive material of 0.15 mm, according to the method described in Example 1, wherein a numerical value of the threshold temperature, as well as black paint, were applied in the area of ​​the heat-sensitive material before its application. The number of layers of the heat-sensitive material was 5, between applications the composition was dried in a thermostat at a temperature of 70 °C for three hours. The thickness of the layer of the heat-sensitive material was 0.2 mm, and its area was 30% of the area of ​​the front surface of the device.The device was covered with a transparent protective film made of PVC, 0.05 mm thick.

[0213] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 90 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 4 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0214] Example 7.

[0215] Lanthanum palmitate with a phase transition temperature of 100 °C was used as an organic substance for preparing the heat-sensitive material according to Example 1, gelatin was used as a binder, and isopropanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of polyester modified with 6.5% hexabromocyclododecane, yellow in color, having a thickness in the area of ​​the heat-sensitive material of 0.3 mm, according to the method described in Example 1, wherein a numerical value of the threshold temperature, as well as black paint, were applied in the area of ​​the heat-sensitive material before its application. The number of layers of the heat-sensitive material was 6, between applications the composition was dried for 24 hours at room temperature. The thickness of the layer of the heat-sensitive material was 0.5 mm, and its area was 30% of the area of ​​the front surface of the device.The device was covered with a transparent protective film made of PVC, 0.05 mm thick.

[0216] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 100 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 2 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0217] Example 8.

[0218] Lanthanum nonadecynate with a phase transition temperature of 10 °C was used as the organic substance for preparing the heat-sensitive material according to Example 1, phenoxy resin was used as a binder, and ethylene glycol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, having a thickness in the area of ​​the heat-sensitive material of 0.5 mm, according to the method described in Example 1, and in the zone free of the heat-sensitive material, a numerical value of the threshold temperature was applied. The number of layers of the heat-sensitive material was 6, between applications the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for one hour. The thickness of the layer of heat-sensitive material was 0.5 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.1 mm thick.

[0219] The device was glued at room temperature to a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 110 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 2 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0220] Example 9.

[0221] Lanthanum capronate with a phase transition temperature of 120 °C was used as the organic substance for preparing the heat-sensitive material according to Example 1, polyethylene was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black PVC Oramask 831, having a thickness in the area of ​​the heat-sensitive material of 0.5 mm, according to the method described in Example 1, and in the zone free of the heat-sensitive material, the numerical value of the threshold temperature was applied. The number of layers of the heat-sensitive material was 5, between applications the composition was dried in a thermostat at a temperature of 60 °C for three hours. The thickness of the layer of heat-sensitive material was 0.35 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.15 mm thick.

[0222] The clip was installed at room temperature on a cylindrical heating element with a diameter of 7 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 120 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 3 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0223] Example 10.

[0224] Zinc nonadecanoate with a phase transition temperature of 130 °C was used as an organic substance for preparing the heat-sensitive material according to Example 1, polycarbonate was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, having a thickness in the area of ​​the heat-sensitive material of 0.45 mm, according to the method described in Example 1, and in the zone free of the heat-sensitive material, a numerical value of the threshold temperature was applied. The number of layers of the heat-sensitive material was 5, between applications the composition was dried for 24 hours at room temperature. The thickness of the layer of heat-sensitive material was 0.4 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.02 mm thick.

[0225] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 130 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 2 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0226] Example 11.

[0227] Zinc palmitate with a phase transition temperature of 140 °C was used as the organic substance for preparing the heat-sensitive material according to Example 1, nitrocellulose was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, having a thickness in the area of ​​the heat-sensitive material of 0.4 mm, according to the method described in Example 1, with the numerical value of the threshold temperature being applied in the area free of the heat-sensitive material. The number of layers of the heat-sensitive material was 6, between applications the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for one hour. The thickness of the layer of heat-sensitive material was 0.45 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.03 mm thick.

[0228] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 140 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 1 second. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0229] Example 12.

[0230] Zinc capronate with a phase transition temperature of 150°C was used as an organic substance for preparing the heat-sensitive material according to Example 1, polyvinylidene fluoride was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, having a thickness in the area of ​​the heat-sensitive material of 0.2 mm, according to the method described in Example 1, and in the zone free of the heat-sensitive material, a numerical value of the threshold temperature was applied. The number of layers of the heat-sensitive material was 5, between applications the composition was dried in a thermostat at a temperature of 60 °C for three hours. The thickness of the layer of heat-sensitive material was 0.3 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.15 mm thick.The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 150 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 1 second. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0231] Example 13.

[0232] Lithium stearate with a phase transition temperature of 210 °C was used as the organic substance for preparing the heat-sensitive material according to Example 1, polybutyl acrylate was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, having a thickness in the area of ​​the heat-sensitive material of 0.15 mm, according to the method described in Example 1, and in the zone free of the heat-sensitive material, a numerical value of the threshold temperature was applied. The number of layers of the heat-sensitive material was 5, between applications the composition was dried for 24 hours at room temperature. The thickness of the layer of heat-sensitive material was 0.4 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.1 mm thick.

[0233] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 210 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 1 second. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0234] Example 14.

[0235] Yttrium caproate with a phase transition temperature of 55 °C was used as an organic substance for preparing the heat-sensitive material according to Example 1, polyethersulfone was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, having a thickness in the area of ​​the heat-sensitive material of 0.25 mm, according to the method described in Example 1, with the numerical value of the threshold temperature being applied in the area free of the heat-sensitive material. The number of layers of the heat-sensitive material was 5, between applications the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for one hour. The thickness of the layer of heat-sensitive material was 0.25 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of 0.15 mm thick PVC.

[0236] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 55 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 3 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0237] Example 15.

[0238] The organic substance used to prepare the heat-sensitive material according to Example 1 was n-hexadecyl-n-pentylhydrogenphosphate with a phase transition temperature of 40 °C, ethylcellulose was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, having a thickness in the area of ​​the heat-sensitive material of 0.15 mm, according to the method described in Example 1, with the numerical value of the threshold temperature being applied in the area free of the heat-sensitive material. The number of layers of the heat-sensitive material was 5, and between applications the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for one hour. The thickness of the layer of the heat-sensitive material was 0.3 mm, and its area was 70% of the area of ​​the front surface of the device.The device was covered with a transparent protective film made of PVC, 0.15 mm thick.

[0239] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 40 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was less than 1 second. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0240] Example 16.

[0241] Palmitic acid anhydride with a phase transition temperature of 60 °C was used as an organic substance for preparing the heat-sensitive material according to Example 1, polymethacrylate was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, having a thickness in the area of ​​the heat-sensitive material of 0.35 mm, according to the method described in Example 1, and in the zone free of the heat-sensitive material, a numerical value of the threshold temperature was applied. The number of layers of the heat-sensitive material was 6, between applications the composition was dried in a thermostat at a temperature of 40 °C for three hours. The thickness of the layer of heat-sensitive material was 0.55 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.02 mm thick.

[0242] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 60 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 2 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0243] Example 17.

[0244] Erucamide with a phase transition temperature of 80°C was used as an organic substance for preparing the heat-sensitive material according to Example 1, polycarbonate was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black PVC Oramask 831, having a thickness in the area of ​​the heat-sensitive material of 0.65 mm, according to the method described in Example 1, and in the zone free of the heat-sensitive material, a numerical value of the threshold temperature was applied. The number of layers of the heat-sensitive material was 7, between applications the composition was dried for 24 hours at room temperature. The thickness of the layer of heat-sensitive material was 0.75 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.03 mm thick.

[0245] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 80 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 4 seconds. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed. Example 17.

[0246] The organic substance used to prepare the heat-sensitive material according to Example 1 was 1-tetradecanol with a phase transition temperature of 40 °C, polybutyl acrylate was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of chloroprene rubber on a siliconized black base with a thickness in the area of ​​the heat-sensitive material of 0.1 mm, according to the method described in Example 1, with the numerical value of the threshold temperature being applied in the area free of the heat-sensitive material. The number of layers of the heat-sensitive material was 5, and between applications the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for one hour. The thickness of the layer of the heat-sensitive material was 0.15 mm, and its area was 70% of the area of ​​the front surface of the device.The device was covered with a transparent protective film made of PVC, 0.05 mm thick.

[0247] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 40 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was less than 1 second. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0248] Example 18.

[0249] The organic substance used to prepare the heat-sensitive material according to Example 1 was docosanitrile with a phase transition temperature of 55 °C, polybutyl methacrylate was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black PVC Oramask 831, having a thickness in the area of ​​the heat-sensitive material of 0.15 mm, according to the method described in Example 1, with the numerical value of the threshold temperature being applied in the area free of the heat-sensitive material. The number of layers of the heat-sensitive material was 5, and between applications the composition was dried for 24 hours at room temperature. The thickness of the layer of the heat-sensitive material was 0.25 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent protective film made of PVC, 0.15 mm thick.

[0250] The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 55 °C with a given accuracy, and the fact of the device's operation was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the base color. The time during which the phase transition occurred and the change in the transparency of the heat-sensitive material was 1 second. After cooling the device to room temperature, the preservation of the transparency of the heat-sensitive material was visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0251] Example 19.

[0252] The organic substance used to prepare the heat-sensitive material according to Example 1 was n-docosylamine with a phase transition temperature of 65 °C, polyvinyl butyral was used as a binder, and ethanol was used as a solvent. The suspension was applied by silk-screen printing to a base made in the form of a clip without additional fastening elements made of black OraJet 3106SG PVC with a recess in the area of ​​the heat-sensitive material, having a thickness in the area of ​​the heat-sensitive material of 0.55 mm, according to the method described in Example 1, with the numerical value of the threshold temperature being applied in the zone free of the heat-sensitive material. The number of layers of the heat-sensitive material was 7, between applications the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for one hour. The thickness of the layer of the heat-sensitive material was 0.75 mm. The size of the front surface of the device is 12 * 12 mm (area - 144 mm 2), the size of the layer of heat-sensitive material is 10*10 mm (area - 100 mm 2). The device was covered with a transparent protective film made of PVC, 0.05 mm thick. The device was installed at room temperature on a cylindrical heating element with a diameter of 15 mm. Part of the heating element was controlled to heat up at a rate of 5 °C / min to a temperature of 65 °C with a specified accuracy, while the rest of the heating element was not heated. The fact of operation of the part of the device that was heated was recorded by visually recording an increase in the transparency of the corresponding section of the heat-sensitive material with the appearance of the color of the base. After cooling the device to room temperature, the preservation of the transparency of the corresponding section of the heat-sensitive material was visually recorded. Then the heating element was completely heated at a rate of 5 °C / min to a temperature of 65 °C with a specified accuracy.The fact of the complete operation of the device was recorded by visually recording the increase in transparency of the entire layer of heat-sensitive material with the manifestation of the base color. The time during which the phase transition occurred and the change in transparency of the heat-sensitive material was 2 seconds. During the heating and cooling cycles, the tight fixation of the device on the surface of the heating element was observed.

[0253] Example 20.

[0254] The area of ​​the base, made in the form of a clip without additional fastening elements made of black PVC OraJet 3951, onto which the heat-sensitive material will be applied, was sealed with a protective polyethylene film, the free area was covered with pigmented yellow Tempilaq heat-sensitive paint with a reversible color change temperature of 113 °C. After the paint dried, the protective polyethylene film was removed and a numerical value of the threshold temperature was applied to the surface of the base containing the heat-sensitive paint using solvent dyes. The thickness of the base containing the heat-sensitive paint was 0.45 mm. Then the protective polyethylene film was glued to the area onto which the heat-sensitive material should not get, the heat-sensitive compound was applied using the silk-screen method in 7 layers. After the layer completely dried, the protective film was removed.Lanthanum nonadecinate with a phase transition temperature of 110 °C was used as an organic substance for preparing the heat-sensitive material according to example 1, butyl methacrylic resin was used as a binder, and ethanol was used as a solvent. The number of layers of the heat-sensitive material was 6, between applications the composition was dried in a thermostat at a temperature of 60 °C for three hours. The thickness of the layer of the heat-sensitive material was 0.6 mm, and its area was 70% of the area of ​​the front surface of the device. The device was covered with a transparent elastic protective film made of PVC, 0.05 mm thick.

[0255] The device was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 115 °C with a given accuracy and the fact of the device's heat-sensitive material zone triggering with the base color manifestation, as well as the fact of the heat-sensitive paint triggering with a color change, were recorded. The time during which the phase transition and the change in the transparency of the heat-sensitive material occurred was 1 second. After the device was cooled to room temperature, the preservation of the heat-sensitive material zone transparency and the return of the heat-sensitive paint color to its original color were visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed to be preserved.

[0256] Example 21.

[0257] The area of ​​the base, made in the form of a clip without additional fastening elements made of red PVC Oramask 831, onto which the heat-sensitive material will be applied, was sealed with a protective polyethylene film, the free area was covered with pigmented yellow Hallcrest SC thermal paint with an irreversible color change temperature of 80 °C. After the paint dried, the protective polyethylene film was removed and a numerical value of the threshold temperature was applied to the surface of the base containing the thermal paint using solvent dyes. The thickness of the base containing the thermal paint was 0.55 mm. Then the protective polyethylene film was glued to the area that should not be exposed to the heat-sensitive material, this area was covered with solvent black dye and the thermal composition was applied using silk-screen printing in 6 layers. After the layer completely dried, the protective film was removed.Zinc capronate with a phase transition temperature of 150 °C was used as an organic substance for preparing the heat-sensitive material according to example 1, phenol-formaldehyde resin was used as a binder, and ethanol was used as a solvent. The number of layers of the heat-sensitive material was 6, between applications the composition was dried in a vacuum chamber at 100 mm Hg and 20 °C for one hour. The thickness of the layer of heat-sensitive material was 0.45 mm, and its area was 30% of the area of ​​the front surface of the device. The device was covered with a transparent elastic protective film made of PVC, 0.15 mm thick.

[0258] The device was glued at room temperature to a cylindrical heating element with a diameter of 1 mm, which was then heated in a controlled manner at a rate of 5 °C / min to a temperature of 80 °C with a given accuracy, and the fact of the thermal paint triggering with a color change was recorded. Then heating was continued to a temperature of 150 °C, and the fact of the device's thermally sensitive material zone triggering with the base color manifestation was recorded. The time during which the phase transition occurred and the change in the transparency of the thermally sensitive material was 2 seconds. After cooling the device to room temperature, the preservation of the transparency of the thermally sensitive material zone, as well as the preservation of the changed color of the thermal paint, were visually recorded. During heating and after cooling, the tight fixation of the device on the surface of the heating element was revealed.

[0259] The examples given do not limit the declared technical solution, however, they clearly reveal particular cases of the implementation of the declared technical solution, and also confirm the achievement of the technical result associated with ensuring increased safety of operation of electrical equipment due to the rapid, reliable and accurate detection of defects associated with excessive heating, by irreversible registration of the fact that an element of electrical equipment exceeds a specified threshold temperature, a device that is convenient and reliable to mount on wires and other elements of electrical equipment.

[0260] The technical solution has been disclosed above with reference to a specific embodiment of its implementation. Other embodiments of the technical solution may be obvious to specialists, which do not change its essence as disclosed in this description. Accordingly, the technical solution should be considered not limited in scope by the description and examples provided.

Claims

Formula 1. A device for registering the excess of a threshold temperature, comprising a base that is opaque to at least part of the visible light, made in the form of a clip, partially covered on the front side with a heat-sensitive material that irreversibly changes transparency relative to the original state when heated above the threshold temperature.

2. The device according to claim 1, wherein the base is elastic and includes halogen-containing polymers, predominantly containing the structural unit -CH2CHCI-, predominantly polyvinyl chloride, predominantly cast polyvinyl chloride.

3. The device according to item 1, characterized in that the base is made in the form of a single structure with the possibility of fixing onto electrical wires, preferably with a diameter of 1 to 10 mm, without additional elements.

4. The device according to claim 1, characterized in that the base is provided with elements for snapping the device onto electrical wires, preferably with a diameter of 1 to 10 mm.

5. The device according to item 1, characterized in that the area of ​​the front surface of the base is from 3 mm 2 , preferably not less than 10 mm 2 .

6. The device according to item 1, characterized in that the heat-sensitive material is located in a recess made in the material from which the base of the clip is made.

7. The device according to I.1, in which the heat-sensitive material is covered with an elastic protective film that is transparent to at least part of the visible light, preferably made of polyvinyl chloride, most preferably cast polyvinyl chloride.

8. The device according to claim 1, in which the heat-sensitive material in its initial state is colored white, and when the transparency of the heat-sensitive material changes, a visual color transition from white to black occurs.

9. The device according to claim 1, characterized in that the heat-sensitive material irreversibly changes transparency when heated in a range not exceeding 5 °C, preferably not exceeding 2 °C relative to the threshold temperature indicated on the device.

10. The device according to claim 1, in which the heat-sensitive material in its initial state has a microstructure including a solid phase and voids forming a continuous gas phase, the proportion of which is at least 50 vol.%, and is designed with the ability to irreversibly change its appearance upon reaching the specified threshold temperature due to the destruction of the microstructure of the heat-sensitive material, accompanied by the fusion of particles of the solid phase, a decrease in the proportion of voids and an increase in its transparency with the manifestation of the color of the base.

11. The device according to item 10, in which the solid phase of the heat-sensitive material includes an organic substance containing a structural fragment C n H(2n+i), where n > 5.

12. The device according to item 10, in which the solid phase of the heat-sensitive material includes an organic substance that is selected from the group: fatty aliphatic acids containing structural fragments C n H(2n+i) with n > 12; salts of fatty aliphatic acids containing structural fragments C n H(2n+i) with n > 5; alkanes containing at least 20 carbon atoms; dialkylphosphinic acids containing structural fragments C n H(2n+i) with n>5; amides of fatty aliphatic acids containing structural fragments C n H(2n+i) with n > 5; fatty acid anhydrides containing structural fragments C n H(2n+i) with n > 10; fatty aliphatic alcohols containing structural fragments C n H(2n+i) with n > 14; fatty aliphatic amines containing structural fragments C n H(2n+i) with n > 17; nitriles of fatty aliphatic acids containing structural fragments C nH(2n+i) with n>19 is preferably selected from the group: palmitic acid, stearic acid, behenic acid, tetracosane, erucamide, stearyl alcohol, cetyl alcohol, polyethylene, wax, paraffin, salts of saturated fatty carboxylic acids of rare earth metals, in particular lanthanum, yttrium, ytterbium, scandium.

13. The device according to item 11, in which the mass content of the solid phase in the heat-sensitive material is not less than 50 mass%, and the heat-sensitive material contains a polymer binder that is transparent to at least part of the visible light in an amount of 1-30 mass%.

14. The device according to claim 1, characterized in that it has dielectric properties, preferably has an electrical strength of at least 5 kV / mm.

15. The device according to claim 1, wherein the heat-sensitive material is designed to change transparency when heated to a temperature exceeding the threshold, within no more than 5 seconds, preferably no more than 2 seconds.

16. A device according to any of paragraph 1, characterized in that it can be used for color marking of electrical equipment phases due to the color of the base paint.

17. The device according to claim 1, wherein the area of ​​the surface of the base coated with the heat-sensitive material is from 3 to 97% of the area of ​​the front surface of the base, preferably not less than 30% of the area of ​​the front surface of the base.

18. The device according to claim 1, wherein the base has light-reflecting properties or is colored using a substance having luminescent properties.

19. The device of claim 1, wherein the base is at least partially colored using a substance that is capable of reversibly or irreversibly changing color upon heating.

20. The device according to claim 1, wherein the thickness of the base in the area of ​​the heat-sensitive material is no more than 3 mm, preferably no more than 1 mm.

21. The device according to claim 1, characterized in that, with uneven heating, a change in transparency occurs only in that area of ​​the heat-sensitive material of the clip that was heated above the threshold temperature.

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