RU223351U1 - Thermal indicator clip for several threshold temperatures - Google Patents

Abstract

The utility model relates to devices for recording exceeding threshold temperatures, namely to devices that are a clip that makes it possible to irreversibly register the fact that wires and other elements of electrical equipment exceed specified temperatures. A device for recording exceeding threshold temperatures includes a base, opaque to at least part of visible light, made in the form of a clip, partially coated on the front side with various heat-sensitive materials, each of which is designed to irreversibly change transparency relative to the initial state when heated to its corresponding threshold temperature. The utility model provides increased operational safety of electrical equipment due to the rapid, reliable and reliable detection of defects associated with excessive heating, by irreversibly recording the fact that an element of electrical equipment exceeds specified threshold temperatures, a device that is conveniently and reliably mounted on wires and other elements of electrical equipment. 20 z.p., 21 notes, 8 ill.

Description

Field of technology to which the claimed utility model relates

The utility model relates to devices for recording exceeding threshold temperatures, namely to devices that are a clip that makes it possible to irreversibly register the fact that wires and other elements of electrical equipment exceed specified temperatures.

State of the art

An increase in temperature is one of the first and most common signs of the development of defects in various equipment, such as an increase in transient contact resistance in the electric power industry, malfunctions of bearings in mechanics, interturn short circuits in the windings of electric motors, failure of chargers or batteries in household appliances. Timely detection of such overheating allows the malfunction to be eliminated in advance, to prevent equipment damage, emergency situations and associated 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 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.).

It is especially important to identify at an early stage overheating of wires in electrical panels 220-380 V of buildings and structures for residential, social or industrial purposes, 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.

To identify defects associated with exceeding the maximum permissible temperatures of electrical equipment and wires, various diagnostic methods are used. Means of continuous monitoring of overheating include chemical or mechanical temperature indicators, which can be of two types: reversible (changing appearance only when heated and returning it when cooled) and irreversible (changing appearance after exceeding a given temperature and maintaining it after cooling).

Structurally, most temperature indicators are stickers with a heat-sensitive layer applied to the front surface. An example of such devices for controlling overheating is the invention described in document US 7600912 B2 (publication date March 20, 2007) and which is a single-layer or two-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 lowering the temperature, the dye crystallizes and the color is restored. The peculiarity of this kind of inventions is that they make it possible to inform 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.

Unlike reversible indicators, irreversible indicators allow not only to identify, but also to record the fact that a threshold temperature has been exceeded. The use of irreversible thermal indicators makes it possible to assess the condition without creating a maximum load mode, both on operating equipment and on equipment taken out for repair.

Irreversible heating indicators can be classified according to their operating principle. Indicators are known that are based on the mechanical destruction of a temperature-sensitive element, on the chemical reaction of components of a thermal composition, or on the phase transition of a temperature-sensitive component.

An example of a temperature indicator based on mechanical destruction is described in the source [US 6176197 B1, publication date 02.11.1998], according to which the temperature indicator is a closed hollow transparent elongated tube with two compositions different in color, isolated from each other by a polymer partition having melting temperature close to the melting temperatures 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's contents changes. Features of the invention include the impossibility of controlling 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 the creation of a flexible device that fits tightly to the entire controlled surface, and also does not imply any fastening elements that allow the device to be securely fixed.

The chemical reaction of etching a metal substrate with an activator, which begins when a certain temperature is reached, is described in the patent [EP 2288879 B1, publication date 06/04/2008]. The indicator changes color from silver-white or mirror-like to colorless and can be used for temperature monitoring in food, medical, and 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 be attached to various surfaces. Among the commercially available indicators, the operating principle of which is based on a chemical reaction, we can highlight indicator stickers of the Retomark model, supplied by LLC Innovative Company YALOS (https://www.yalosindicator.com/product/termoindikatory-kontrol-temperatury).

The presented irreversible thermal indicators, the operating 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 threshold temperature values with an accuracy of at least 5°C, regardless of the time of exposure to temperature, which makes the described inventions unsuitable for recording 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 a threshold value, the chemical reaction may not be completed and a change in the color of the indicator either will not occur or will be insufficient for detection. In addition, due to the reversibility of color transition reactions, it is possible for the triggered indicator to return to its original color after a long exposure at low temperature.

A separate disadvantage of indicators based on mechanical or chemical principles is also that when the layer of the thermosensitive element is deformed, premature operation of the indicator may occur, and their initial design in the form of devices with a shape other than flat is not always possible.

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

Irreversible indicators based on the principle of phase transition of a temperature-sensitive component can be made in the form of thermal indicator paint. A thermochromic indicator containing a substrate and a coating with particles of solid crystalline material, air voids and a small amount, for example 5-40% by weight of the coating, of a binder, is described in the source US 2010247900 A1, publication date 09.30.2010. In this case, the particle size of the material must be such that the coating has high opacity at a temperature below the melting onset temperature due to scattering of visible light, which decreases when the melting onset temperature is reached with the formation of a transparent coating when the melting onset temperature is reached. A feature of this invention is the large temperature range at which a change in transparency occurs, as well as the long response time of the device.

Thermal indicator paints or varnishes can be applied to any surface shape. The use of temperature indicator paints and varnishes, the principle of operation of which is based on the melting of pigment, is described in a number of documents, including, for example, CN 112322134 A (publication date 09/23/2020), CN 111849346 A (publication date 07/11/2020), CN 108610694 A (date of publication 09.12.2016), SU 1765145 A1 (date of receipt 30.10.1989), SU 576334 A1 (date of publication 25.05.1976). Typically, such paints consist of synthetic resins, fillers and heat-sensitive components dispersed in water or a solvent. When heated above a given temperature, the heat-sensitive component melts, which leads to a change in 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 slightly, which makes it easy to record the fact of overheating during 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. To do this, you need to make special notes.

- drainage of indicator paint when the threshold temperature is exceeded. When exposed to temperature and melting of a heat-sensitive component, paint can drain from the surface and get onto open elements of the electrical installation or moving parts of mechanisms, which can 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, etc. accidents.

- impossibility of applying a uniform layer on complex surfaces. The consequence of this is that it is impossible to determine the exact temperature, since the thicker the layer, the higher the difference between the surface temperature and the phase transition (trigger) temperature.

- low adhesion and difficulty in applying paint to wires made of non-adhesive materials (silicone, polyethylene, fluoroplastic). A large amount of hot-melt pigment required for clear visualization of overheating, as a rule, 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 stress.

- dependence of the temperature of paint operation on the chemical composition of the surface on 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 paintwork of the engine housing, various substances, primarily flame retardants and plasticizers, can be extracted into the temperature indicator paint. Such substances may result in the formation of eutectic mixtures with the hot melt component or otherwise affect the response temperature.

Another option for thermal indicators based on the phase transition of a temperature-sensitive component is thermal indicator stickers.

Thermal indicator stickers can be made in single-temperature and multi-temperature versions; among the manufacturers of multi-temperature thermal indicators in the form of stickers we can highlight: TermoElectrika LLC (https://www.lesiv.pro/%D0%BA%D0%BE%D0%BF %D0%B8%D1%8F-l-mark-pro), LLC "Innovative Company "YALOS" (https://www.yalosindicator.com/product/termoindikatory-kontrol4emperatury) CJSC "NPF "Luminofor" (https:/ /luminophor.ru/catalog/termoindikatomye-materialy/termoindikatory-plavleniya-marki-tin/).

The advantage of multi-temperature indicators relative to single-temperature ones is that they make it possible to determine not only the fact that a given temperature has been exceeded, but also to track the dynamics of the development of a defect, record several threshold temperatures of the equipment surface during overheating, and provide the ability to compare overheating temperatures of identical elements (equipment units).

Thermal indicator stickers do not have a number of disadvantages inherent in indicator paints. So, the response temperatures may be indicated on the sticker. Heat-sensitive compounds and an adhesive layer are applied at the factory in a uniform thin layer onto a polymer base. This approach ensures specified response and adhesion characteristics regardless of operating conditions. The polymer base prevents contact of the heat-sensitive composition with the surface of the controlled element. In addition, most thermal indicator stickers are additionally covered with a polymer film, which protects the hot-melt composition from mechanical or chemical influence and does not allow it to drain when melted after activation.

As noted earlier, temperature indicators are used in a wide variety of areas. The highest technical requirements are placed on temperature indicators used in the electrical power industry.

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 flammability;

- have high electrical strength and dielectric properties;

- irreversibly register exceeding threshold temperatures;

- ensure the necessary accuracy of operation;

- have flexibility and strength;

- have good fixation on the controlled element for a tight fit to various surfaces.

Moreover, a device with such characteristics can be used in any other field.

For the most rapid and reliable detection of defects accompanied by overheating of electrical equipment elements, it is necessary to have close contact of the thermal indicator with the controlled surface, without air gaps that reduce the speed and efficiency of heating of the thermal indicator due to the low thermal conductivity of the air. In addition, temperature indicators must be conveniently and securely attached to the controlled elements, without peeling off from them during operation.

To use temperature indicators to record the excess temperature of the surface of electrical equipment elements or various mechanisms, it is necessary to take into account that often the surface of such elements has a complex geometry with a radius of curvature of 2 mm (for example, small-section electrical wire strands with or without insulation, steel-aluminum wires of overhead power lines, hardware clamps, surface of coils, blades of bolted contact connections, contact lamellas, jaws of contact connections of fuses, etc.). The surfaces of metal conductive elements can constantly expand/contract due to multiple heating/cooling cycles caused by changes in load current.

Installation of thermal indicator stickers on contact connections of wires and other elements of electrical equipment with a small radius of curvature leads to large deformation of both the material of the sticker itself and its adhesive layer, as well as the heat-sensitive layer. This can lead to the fact that after removing the pressure with which this sticker was glued to a curved surface, the elastic force will exceed adhesion (the force of adhesion 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 thing can happen when the linear dimensions of the controlled surface change, including due to thermal expansion of the surface material when it is heated.

Manufacturers of thermal indicator stickers in their documentation often indicate the need to install their products on flat surfaces, which is associated not only with their insufficient flexibility and elasticity, but also with the fact that deformation may cause loss of the functional properties of heat-sensitive materials. Such stickers cannot be used for temperature control of surfaces that have a small radius of curvature, surfaces of complex shape, as well as surfaces that can change their linear parameters, since the reliability of recording temperature increases will be significantly reduced.

The reasons for this are:

- in the case of using heat-sensitive materials based on the destruction of the membrane, premature operation 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, heat-sensitive materials may peel off from the base, as well as cracks may form on their surface. As a result, false alarms will occur or a decrease in the visibility of the triggered device will be observed, caused by insufficient heating of heat-sensitive materials when threshold temperatures are exceeded;

- in the area where the sticker peels off from the controlled surface, an air bubble may form, which will act as thermal insulation. The latter can lead to “non-operation” of the thermal indicator due to the temperature difference between the controlled surface and the heat-sensitive material or a decrease in the response speed;

- uneven heating of the surface of heat-sensitive materials in the area of sticker peeling, in which part of the layer of heat-sensitive material changes appearance (becomes transparent with the color of the base appearing), and part retains its original (opaque) state, which can lead to an unreliable conclusion about the localization of registered overheating.

The base of the thermal indicator device and the layer of heat-sensitive materials itself must have a minimum thickness to ensure 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 the passage of short circuit currents, excessive starting load of motors, cold running, switching or other processes. In addition, a minimum thickness of the thermal indicator sticker is necessary to ensure the necessary heat removal from the controlled surface. Otherwise, installing a temperature indicator will lead to an additional increase in the temperature of the controlled element and an increase in the rate of development of the defect.

Among the solutions known from the prior art, one can highlight devices for recording the maximum heating temperature of the equipment surface, made in the form of a sticker with a flexible base with a thickness of no more than 1 mm and a response speed of heat-sensitive compounds of less than 5 seconds when heated above the threshold temperature [RU 2022114366, filing date 27.05. 2022]. At the same time, the time for registering overheating when the devices quickly heat up to a temperature 5°C higher than the recorded one is less than 5 seconds, which provides indication of defective components even during short-term overheating under conditions of peak loads of the monitored components.

However, despite the advantages of thermal indicator stickers described above, their main disadvantage is the difficulty of installation on the wires of electrical panels. Existing regulatory requirements allow for 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 the mounted wire. Mechanical impact on the wires when installing the sticker can lead to deterioration in the quality of the contact due to loosening of the contact connection or partial removal of the wire from the terminal under the influence of the applied force. The consequence of this will be a decrease in reliability and an increase in the risk of fire. Separately, it should be noted that winding thermal indicator stickers onto a live wire (without disconnecting from the network) can pose a danger to the installer. When winding a thermal indicator sticker onto a wire, it is not always possible to predict in advance the final location of the thermally sensitive elements. Displacement of indicator points can lead to reduced visibility of the response during inspections, missed defects and reduced reliability. If the thermal indicator sticker is not properly attached to the surface of the wire, peeling or a decrease in the tightness of the sticker may occur. Peeling and loss of functional properties of thermal indicator stickers can also occur when the linear dimensions of the controlled surface change, including due to thermal expansion of the surface material when it is heated by electric current. This is especially true in distribution networks, the load of which varies significantly throughout the day.

Reliability of fastening and safety of operation of thermal indicator stickers is directly related to the strength of adhesion of the sticker 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 contaminants or special coatings on it. In some cases, the materials from which wires or other elements are made have special anti-adhesive coatings on which it is impossible to reliably attach thermal indicator stickers. Some difficulties may be associated with the adhesive layer. It may lose its properties over time, and adhesion may deteriorate significantly 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 if repair work is necessary.

These disadvantages 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 a threshold temperature, which is easily installed, in particular, on electrical wires. This device was selected as a prototype of the proposed utility model [https://iriss.com/safe-connect-thermochromic-solution/thermo-clihp-series/]. The clip material contains 5-10% thermochromic composition, which provides an irreversible color change, and 90-95% non-halogenated polypropylene, which has self-extinguishing ability and high dielectric strength. The clip is designed for installation on the outer insulation of an electrical cable by snapping into place with a little force. It can be safely mounted on controlled live electrical components. Depending on the size, the described devices can be installed on wires with a diameter of 2.3 to 31 mm. Since the fastening of the clip is ensured by the elasticity of the material from which it is made, such an indicator can be reliably used on wires operating with variable loads, that is, in a wide temperature range.

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 a threshold temperature is reached. After cooling, the pigment solution does not crystallize to its original state, which ensures that the appearance of the fired product is preserved. The initial temperature of the color change of the clip in question is 53°C, the accuracy of the beginning of the color change declared by the manufacturer is ±1°C, and the response range of the clip is 18°C, since, as indicated in the technical characteristics of the described device, a complete irreversible color change of the clip occurs at ( 71±1)°С. It should also be noted that the range of response temperatures shown in the prototype clips is narrow, which does not allow them to be used to assess the condition of contacts and contact connections of electrical equipment. The time it takes for the clip proposed in the prototype to operate (color transition) is up to 20 seconds, which does not allow detecting short-term overheating of the controlled elements and can lead to false alarms or failures 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 the use of additional reference books or technical documentation.

Based on the level of technology we have studied in detail, it follows that, despite the large selection of temperature indicators, different both in the mechanism of action and in design, there is a need for devices that are convenient and safe for installation and operation for recording the excess of threshold temperatures of electrical wires, having:

- high accuracy and speed of operation,

- irreversibility of operation,

- low flammability and flammability,

- high electrical strength and dielectric properties,

- having flexibility, strength and the ability to securely attach for a tight fit to various surfaces.

In this case, the principle of operation of such indicators should be based on the melting of heat-sensitive components, providing:

- preservation of the original state at a temperature slightly lower than the corresponding threshold,

- independence of the response temperature from the exposure time,

- no premature operation.

The utility model is aimed at creating a safe, convenient and easy-to-install and operate device for irreversibly recording the fact of exceeding threshold temperatures in electrical installations, made in the form of a clip.

Terms and definitions used in this utility model

By “clip” we mean an element made in the form of a three-dimensional figure with a through internal cavity, preferably round in cross-section, in which a cut is made that allows the clip to be installed on cylindrical or other objects with a round cross-section, without the use of additional fasteners. In relation to the present utility model, a clip is understood as 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.

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

The term "temperature-sensitive material" means a material that becomes more transparent to at least a portion of visible light relative to its original state when heated above a threshold temperature, and does not return to its original state upon subsequent cooling. The temperature-sensitive material may consist, for example, of an individual organic compound or a salt of an organic acid, which undergoes a phase transition when a threshold temperature is reached, or of a mixture of substances. In addition, the heat-sensitive material may additionally include a binder, such as organic resins, for better adhesion of the heat-sensitive material on a flexible base, and other additives.

In this utility model, the term “glazing” is used to denote the process of formation of a uniform layer of one thermodynamic phase around a particle of another thermodynamic phase.

The term "threshold temperature" or "threshold temperature" refers to the numerical value of temperature at which an irreversible change in the properties of a heat-sensitive material occurs. In the claimed utility model, the accuracy of recording exceeding the threshold temperature is 5°C.

The term “accuracy of recording of exceeding the threshold temperature” means the following:

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

2. At a temperature equal to or greater than the threshold temperature of the corresponding temperature sensitive material plus the stated accuracy value, the corresponding temperature sensitive material is transparent and the device takes on a different appearance from the original one.

3. The exact value of the phase transition temperature of the thermosensitive component is within the declared range and is not further established. The accuracy of recording exceeding the threshold temperature determined by this utility model is 5°C.

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

In this utility model, the term “actuation” is applied to a heat-sensitive material that has undergone a phase transition with an increase in transparency. A device in which the temperature-sensitive material has changed transparency is designated as “triggered.”

A “defect” is an object’s non-compliance with the requirements established by the documentation for at least one indicator.

“Fire resistance” refers to the ability of a material to resist combustion under the influence of an ignition source.

The term "electric strength" defines the ability of a given device to withstand electrical voltage applied to it. In other words, electrical strength is the minimum electric field strength at which breakdown of the device occurs.

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 breakdown of the device occurs exceeds the dielectric strength of air.

The term “elasticity” reveals 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 restores its original shape and size after the influence of this force ceases.

The term “fast heating” corresponds to heating the surface with the device installed on it at a rate of at least 1°C/s. The absolute value was selected expertly based on the heating rate of electrical conductors when emergency conditions, short circuit currents or inrush currents occur.

The term “transparent” refers to the property of a material to transmit more than 90% of the light incident on it. The term "opaque" describes a material that transmits no more than 50% of the light incident on it.

The term “elasticity” reveals the ability of a material, when bent around a cylindrical surface, to repeat its shape without loss of 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 removal of this force.

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

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

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

The term "radius of curvature" of curved and cylindrical surfaces refers to the maximum radius of the circular arc that best fits those surfaces. In relation to the present utility model, “small radius of curvature” means a radius of curvature of 2 mm or more.

The term “cylindrical surface” means a developable closed or open ruled surface formed by the parallel movement of a straight line along some curved guide.

By “elongation to break” is meant the numerical value of the elongation of a product or its parts during stretching, above which its physical integrity is violated and rupture 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.

"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 chemical structure or nanoparticles, 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 relation to this utility model, “irreversible change in microstructure” means an irreversible change in the physical, optical or mechanical properties of a material relative to the initial state, accompanied by a change in its microstructure, that is, the spatial arrangement of particles or individual phases of the material, their size or shape, up to the complete merging of particles and formation of a single phase.

By “surface profile of maximum temperatures” is meant an image showing the distribution of maximum values of temperature fields on a monitored surface and allowing one to determine areas of the surface that were heated above threshold temperatures over a given period of time.

The term "solid phase" reveals the structure of a material containing particles of a solid substance of arbitrary shape, each of which has at least one point, face or edge in contact with an adjacent particle and interconnected in such a way that each element of the solid phase can be connected to another its element is a single broken line, each point of which is located inside this phase. Depending on the shape and particle size of the solid, the continuous solid phase may have a cellular, granular, fibrous, crystalline or scaly structure.

The term “continuous gas phase” characterizes the relative position of the voids and means that the voids are predominantly “non-isolated” (“connected”) and communicate with each other through holes, pores or channels. In relation to the present application, a predominantly continuous gas phase is understood to mean an arrangement of voids within a temperature-sensitive material in which the volume of voids interconnected and forming a continuous gas phase exceeds the volume of isolated voids.

The term “substance that causes a change in the transparency of a thermosensitive material when heated above a threshold temperature” means an individual substance included in the composition of a thermosensitive material, having a phase transition temperature near the threshold temperature, the presence of which causes a change in the appearance of the thermal indicator when the threshold temperature is reached, and the removal of which from the thermosensitive material material leads to the loss of properties of an irreversible change in transparency when a threshold temperature is reached.

Essence of a utility model

This utility model was created to improve the safety of operation of electrical equipment, using a simple, safe and easy-to-install device, made in the form of a clip, designed for mounting on wires or other elements of electrical equipment, which allows you to quickly, reliably and reliably identify defects associated with excessive heating, by irreversibly registering the fact that a controlled element of electrical equipment exceeds specified threshold temperatures.

The objective of this utility model is to create such a device in the form of a clip.

The technical result of the claimed utility model is to increase the fire safety of the operation of electrical equipment, in particular, wires and contact connections of electrical equipment when using a thermal indicator device, which makes it possible to detect the fact that several threshold temperatures have been exceeded and the dynamics of the development of a defect.

The technical result is achieved due to a device for recording the exceeding of threshold temperatures, including a base that is opaque to at least part of visible light, made in the form of a clip, partially coated on the front side with various heat-sensitive materials, each of which is designed to irreversibly change transparency relative to the initial state when heating to the corresponding threshold temperature.

The claimed device has the properties of irreversible multi-temperature heat-sensitive indicators, the principle of which is the melting of the corresponding heat-sensitive material, accompanied by a change in transparency relative to the initial state when heated above the corresponding threshold temperature. Using this overheating detection principle 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 of wires and other elements of electrical equipment, as well as tight fit of the temperature-sensitive layer to the controlled elements for reliable registration of the fact of exceeding at least one threshold temperature during the entire service life .

Electrical equipment elements, in particular, polymer-insulated electrical wires located inside electrical panels, were selected as the object of control for this utility model. This is due to several reasons. Firstly, the reliability and reliability of the functioning of electrical installations is an important and integral factor in ensuring the safety and reliability of the operation of almost all types of production, social facilities, transport, urban infrastructure, etc. Secondly, electrical installations are a source of increased fire danger. Fires due to violations of the operating rules of electrical equipment or poor-quality installation take first place after careless handling of fire. Thirdly, in most cases, traditional methods of thermal monitoring, for example, thermal imaging inspection in electrical panels, are ineffective due to the difficulty 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 provide reliable and reliable recording of overheating of electrical equipment elements, including in facilities with a high fire load.

The use of heat-sensitive materials based on melting, accompanied by a change in transparency relative to the initial state when heated to the appropriate threshold temperature, provides:

- irreversibility of the visual effect of the trigger;

- high speed of operation of the device;

- preservation of the original state at a temperature slightly lower than the threshold;

- the required accuracy of the response temperature, regardless of the time of exposure to temperature.

The use of a device with several heat-sensitive materials (multi-temperature thermal indicator) makes it possible to determine not only the fact that at least one set temperature has been exceeded, but also to track the dynamics of the development of a defect, record several threshold temperatures of the equipment surface during overheating, and provide the ability to compare the overheating temperatures of identical elements (equipment units) ).

Making the base of the temperature-sensitive indicator in the form of a clip also has a number of advantages:

- allows you to simply, reliably and safely install a temperature indicator without the use of adhesives, as well as replace it with electrical panel wires, including in hard-to-reach places of the electrical installation, with close proximity of controlled elements of electrical equipment;

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

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

The factors listed above ensure reliable, safe and reliable operation of the device and registration of exceeding specified threshold temperatures by controlled elements of electrical equipment throughout its entire service life.

An information element can be applied to the base, including information about the recorded temperatures, for prompt determination during inspections of the numerical value of the threshold temperatures that the claimed device registers.

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

Also, to prevent the flow of molten heat-sensitive materials during a phase transition, which can cause abnormal and emergency situations, recesses can be made in the material from which the base of the device is made for filling them with heat-sensitive materials.

Preferably, the device has dielectric properties, preferably having a dielectric strength of at least 5 kV/mm.

The material of the base and protective film is preferably selected to ensure that the following criteria are met simultaneously:

- elasticity, flexibility and elasticity necessary for a tight fit of the device to the surfaces of the controlled elements of electrical equipment, which often have complex geometry, while maintaining the ability to register overheating with the stated accuracy;

- ensuring the necessary pressing 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 stress, thermal expansion of the material of the controlled element of electrical equipment;

ensuring the necessary adhesion to the protective film and heat-sensitive material;

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

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

- low electrical conductivity, allowing the device to be installed not only on electrical equipment elements coated 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, motors or various electrical mechanisms. The lack of conductivity and the high value of the breakdown voltage makes it possible to prevent the failure of electrical circuits, the occurrence of a short circuit or the ignition of an electric arc when the clip comes into contact with open conductive elements;

- preservation of the original shape when heated, i.e. the materials of the base and protective film should not melt to their current state when heated to high temperatures, in order to avoid the clip separating from the wire, the softened material flowing down and getting on elements of electrical equipment.

- ensuring stable attachment to the controlled element in a wide temperature range (decomposition temperature, preferably above 150°C).

The most suitable materials for this purpose are halogen-containing polymers, mainly polyvinyl chloride. Polymer materials containing halogen atoms in their structure have some of the highest flexibility and elasticity among known polymers. The introduction of halogen atoms into monomers used as feedstock for polymerization breaks 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 non-halogen-containing monomers, leads to the formation of polymer chains with a large number of stereocenters. Regular polymers derived from non-halogenated monomers without chiral centers tend to form crystalline structures, which reduces their elasticity, while the large number of diastereomers resulting from halogenation of monomers imparts stereochemical disorder to halogenated polymers, which prevents crystallization. Thus, halogen-containing polymer materials have high elasticity and flexibility due to the peculiarities of their chemical structure due to the presence of halogen atoms in the structure of polymers. In addition, halogen-containing materials have good adhesion and low flammability, which further ensures the operational safety of the claimed device and the electrical equipment on which it is placed.

Based on this, in preferred embodiments, the base of the device, made in the form of a clip, is elastic and elastic and includes halogen-containing polymers, preferably containing a structural unit -CH ₂ CHCl-, preferably polyvinyl chloride, preferably cast polyvinyl chloride.

The elastic protective film, transparent to at least a portion of visible light, which may cover the front surface of the device, in particular at least one heat-sensitive material, is also preferably made of polyvinyl chloride, most preferably cast polyvinyl chloride.

The elastic protective film can be attached to the substrate by fusion (welding), adhesive or other methods.

In particular embodiments of the utility model, to ensure self-extinguishing properties of the base of the device when exposed to an open flame, the material of the base or 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 .

Preferably, the base of the device can be made in the form of a single structure with the ability to be fixed to 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. 10 mm, which ensures ease of installation and further increases the reliability of mounting the device on electrical equipment.

In preferred embodiments, the heat-sensitive materials irreversibly change transparency when heated within a range of no more than 5°C, preferably no more than 2°C, relative to the corresponding threshold temperature.

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

In particular cases, at least one heat-sensitive material in the initial state has a microstructure that includes a solid phase and voids, forming a continuous gas phase, the proportion of which is at least 50 vol.%, and is designed to irreversibly change its appearance upon reaching the corresponding threshold temperature due to the destruction of the microstructure, accompanied by the fusion of particles of solid organic matter, a decrease in the proportion of voids and an increase in the transparency of this heat-sensitive material with the appearance of the color of the base (see Fig. 6).

The use of at least one heat-sensitive material with voids allows you to increase the service life, further increase the reliability of determining overheating 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 activation due to an irreversible change in the microstructure, which also has a positive effect on safety of operation of both the clip and the equipment itself. When a thermosensitive material containing voids is melted, an irreversible change in the initial 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 interface due to the irreversible release of the gas contained in the voids to the surface and separation of gas and non-gas media. As a result, upon further cooling, the solid organic substance crystallizes without voids, thereby irreversibly changing the transparency (increases 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 exceedance registration temperature is higher than the set value. Preferably, the proportion of voids of the thermosensitive material after heating above the corresponding threshold temperature value decreases by at least 2 times relative to the initial state, which further increases the contrast of the color transition of the device when the corresponding threshold temperature value is exceeded.

The organic matter of the solid phase of at least one thermosensitive material can be selected from the group: aliphatic fatty acids containing structural fragments C _n H _(2n+1) with n ≥ 12; salts of fatty aliphatic acids containing structural fragments C _n H _(2n+1) with n ≥ 5; alkanes containing at least 20 carbon atoms; dialkylphosphinic acids containing structural fragments C _n H _(2n+1) with n ≥ 5; amides of fatty aliphatic acids containing structural fragments C _n H _(2n+1) with n ≥ 5; aliphatic fatty acid anhydrides containing structural fragments C _n H _(2n+1) with n ≥ 10; fatty aliphatic alcohols containing structural fragments C _n H _(2n+1) with n ≥ 14; fatty aliphatic amines containing structural fragments C _n H _(2n+1) with n ≥ 17; nitriles of aliphatic fatty acids containing structural fragments C _n H _(2n+1) with n ≥ 19.

The use of at least one thermosensitive material of organic compounds as a solid phase substance, which includes one or more aliphatic hydrocarbon chain C _n H _(2n+1) with n ≥ 5, promotes the formation of a crystalline package in which elongated structural fragments of linear hydrocarbons are oriented parallel to each other (A.I. Kitaigorodsky, Molecular Crystals, M.: Nauka, 1971). Due to the fact that the particles of the solid phase substance are formed in the form of fibers, flakes or flat or elongated crystals, that is, they have a two-dimensional structure, the thermosensitive material forms a special microstructure capable of bending and stretching without deformation and loss of functional properties.

Also, the use of solid organic compounds, which include non-polar aliphatic fragments, further increases the electrical strength of the device as a whole, since such fatty aliphatic derivatives have good dielectric properties.

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

In particular cases, the microstructure of at least one thermosensitive material additionally contains a polymer binder that is transparent to at least part of visible light, the phase transition temperature of which is higher than the phase transition temperature of the solid organic substance. In this case, at least one heat-sensitive material contains phase boundaries “solid-transparent solid-gas”; 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 to the surface of the material and separation of the gas and non-gas media occurs, as a result of which a decrease in the contact area of the solid phase and voids is observed, i.e. reducing the area of phase boundaries.

Preferably, the polymer binder is present in at least one temperature-sensitive material in an amount of 1-30 wt. %. In particular cases, a polymer binder coats each individual structural particle of solid organic matter, providing it with “glazing.” The binder is selected to ensure wettability, but not dissolution, of the solid organic matter particles in the polymer binder. Due to this, when “glazing” grains, crystals, fibers, flakes or conglomerates of these particles, additional capture of gas occurs, in the environment of which a thermosensitive material is formed, and its distribution between the “glazed” binder particles of solid organic matter.

In preferred embodiments, the heat-sensitive materials are configured to change transparency when heated to a temperature above a corresponding threshold temperature in no more than 5 seconds, preferably no more than 2 seconds. This is due to the fact that the thickness of the layer of each heat-sensitive material and its structure, together with the thickness of the base of the device, is selected in such a way as to allow the corresponding heat-sensitive material to be heated when short-term overheating occurs during peak load periods and completely transform it into a melt with an “opaque-transparent” color transition "for no more than 5 seconds, preferably no more than 2 seconds, and also provides the necessary heat transfer during air cooling of operating devices. In particular, the thickness of the base in areas of heat-sensitive materials is no more than 3 mm, preferably no more than 1 mm.

Threshold temperatures can be selected from the range 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 values selected for registration, the applied heat-sensitive materials are selected in such a way that the solid organic substance included in the corresponding heat-sensitive material has a melting point near the corresponding threshold temperature, preferably differing from the corresponding threshold temperature by no more than 5°C .

To facilitate visual registration of exceeding threshold temperatures, the surface area of the base coated with heat-sensitive materials is preferably at least 3 mm ² , preferably at least 10 mm ² .

In private embodiments of the device, information elements can be applied to the base, which include information for marking elements of electrical equipment or color marking of phases. In particular, information elements applied to the front surface of its base may contain an inscription containing color, letter, numeric or alphanumeric marking information. In one case, the information element on the base contains information about the end of life date of the device. Also, the base may have a color that corresponds to the established rules for marking elements of electrical equipment. The features listed above serve to give the device for recording the excess of threshold temperatures the properties of electrical equipment marking elements, which also additionally ensures the safety of operation of the equipment on which such devices are placed, due to the following. In the case of contact connections, wires or electrical components, we are talking about small surfaces that, on the one hand, require marking, and on the other hand, temperature control. However, the use of marking devices and devices for recording exceeding threshold temperatures separately is often not possible due to insufficient space on the controlled surface. Using only a temperature indication device without markings can lead to incorrect identification of the defective unit, as well as to an increase in detection time. Thus, a device that combines the properties of a marking device, as well as the properties of temperature indicators, will have a positive impact on the safety of operation of electrical equipment.

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 in the open air or due to inspection in bad weather conditions and in conditions of insufficient visibility, in the dark time of day using a flashlight, as well as for inspecting equipment without artificial lighting and windows, and, as a result, further increasing the safety of equipment operation, the base may have reflective properties or can be painted using a substance with luminescent properties. Ensuring the visibility, as well as the reliability of detecting local heating of electrical equipment elements, is achieved using a variant of the device with a base surface area covered with heat-sensitive materials, from 3 to 97% of the front surface area of the base, preferably, at least 30% of the base front surface area.

In particular cases, the base can be colored using a substance designed to irreversibly change color when heated.

The use of substances when painting the base that are capable of irreversibly changing color when heated to a temperature below the threshold temperature of the base heat-sensitive material, for example, by 10-30°C, makes it possible to inform personnel about the risk of an emergency defect occurring in the future, and thereby provides the opportunity its prevention, with proper response from the personnel responsible for this equipment. Thus, the activation of such a substance, in the absence of activation of the main heat-sensitive material, indicates the presence of overheating of the equipment, which 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 problems that could subsequently lead to development of an already 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, further increases the operational safety of both the claimed device and the equipment as a whole.

Also, the base or some part thereof may be colored using a substance capable of reversibly changing color when heated. For example, a layer of heat-sensitive paint having the above properties can be applied to the front surface.

The presence of a substance capable of reversibly changing color when heated makes it possible to inform personnel not only about exceeding the corresponding threshold temperature 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 can be a source of increased danger. Thus, the presence of a substance capable of reversibly changing color when heated further increases the safety of operation of both the claimed device and the equipment as a whole.

Brief description of drawings

The utility model will be more understandable from the description, which is not restrictive and is given with reference to the accompanying drawings, which show:

Fig. 1 - A device for recording exceeding threshold temperatures, made in the form of a clip with additional fastening elements, with recesses in the base material filled with heat-sensitive material, and with additional coloring in areas of heat-sensitive materials (a top view in section, b - side view in section) .

Fig. 2 - Frontal view of a device for recording exceeding threshold temperatures, made in the form of a clip, the base of which has luminescent properties, with additional coloring in the area of heat-sensitive materials and information elements, including numerical values of threshold temperatures and located under heat-sensitive materials: 2a - initial view of the device, 2b - partially activated device after exceeding the first threshold temperature, 2c - partially activated device after exceeding the second threshold temperature, 2d - partially activated device after exceeding the third threshold temperature, 2d - view of the device after further cooling to room temperature.

Fig. 3 Three-dimensional model of a device for recording exceeding threshold temperatures, made in the form of a clip with additional fastening elements and information elements, including numerical values of threshold temperatures and located next to heat-sensitive materials.

Fig. 4 - A device for recording exceeding threshold temperatures, made in the form of a clip with additional fastening elements, additional painting in areas of heat-sensitive materials and a protective film covering heat-sensitive materials (sectional top view).

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

Fig. 6 Microstructure of a thermosensitive material with particles of organic matter in the form of flakes and their conglomerates, a binder and voids before actuation (a) and after actuation (b).

Fig. 7 - Frontal view of a device for recording exceeding threshold temperatures, made in the form of a clip: (a) the initial view of the device, (b) a partially activated device after spot heating of the controlled surface above one of the threshold temperature values with a change in the transparency of only that area of the corresponding heat-sensitive material, which has been subjected to heating above the appropriate threshold temperature, while maintaining the opaque region of the material in its remaining zone that has not been subjected to heating, as well as maintaining the opacity of other heat-sensitive materials.

Fig. 8 - Layered structure of a device for recording exceeding threshold temperatures, made in the form of a clip, in areas of heat-sensitive materials: (a) - with a sealed transparent protective layer, (b) - with a transparent protective layer, in which a gap is made between the protective layer and the base, (c) - with a transparent protective layer in which micro-holes are made.

In fig. Figure 1 shows a device for recording exceeding threshold temperatures, which is an opaque base 1, made in the form of a clip, containing additional fastening elements 6: (a) top view of a cross-section of the device, (b) side view of a longitudinal section of the device. On the front side of the base material there are recesses filled with heat-sensitive materials 2. In FIG. 1 shows a particular version of a device with two heat-sensitive materials, in which the base 1 is yellow for marking the phases of electrical equipment and is painted black 3 in the zone of heat-sensitive materials.

In fig. Figure 2 shows the front side of the device for recording exceeding threshold temperatures, which is an opaque base 1, made in the form of a clip and having luminescent properties, and heat-sensitive materials 2 applied to its front side: in the initial state before heating (a), after heating to the first threshold temperature of the first heat-sensitive material (b), after heating to the second threshold temperature of the second heat-sensitive material (c), after heating to the third threshold temperature of the third heat-sensitive material (d) and after further cooling to room temperature (e). In fig. 2 shows a particular version of the device with three heat-sensitive materials and with information elements 4, including numerical values of threshold temperatures and located under the heat-sensitive materials, the base 1 is painted black in the area of the heat-sensitive material.

In fig. Figure 3 shows a three-dimensional model of a device for recording exceeding threshold temperatures, which is an opaque base 1, made in the form of a clip, containing additional fastening elements 6, and heat-sensitive materials 2 applied to its front side. FIG. 3 shows a particular version of the device with four heat-sensitive materials and inscriptions indicating the recorded threshold temperatures 4 located on the base next to the heat-sensitive materials, and the base 1 is yellow.

In fig. Figure 4 shows a cross-section of a device for recording exceeding threshold temperatures, which is an opaque base 1, made in the form of a clip, containing additional fastening elements 6, on the front surface of which heat-sensitive materials 2 are applied, covered with a transparent elastic protective layer 5. In FIG. 4 shows a particular version of the device, in which the base 1 is yellow and painted black 3 in the area of heat-sensitive materials.

In fig. Figure 5 shows a three-dimensional model of a device for recording exceeding threshold temperatures, which is an opaque base 1, made in the form of a clip, containing additional fastening elements 6, and heat-sensitive materials 2 applied to its front side. FIG. Figure 5 shows a particular version of the device with two heat-sensitive materials and a base 1 painted red, corresponding to the phase markings.

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

In fig. Figure 7 shows the front side of the device for recording exceeding threshold temperatures, which is an opaque base 1, made in the form of a clip, and thermosensitive materials 2 applied to its front side: before heating (a) and after spot heating (b) of the controlled surface, as a result of which the change in transparency occurred only in that area 12 of one of the heat-sensitive materials 2, which was subject to heating above the corresponding threshold temperature, while maintaining the original appearance of the rest of the area of the corresponding heat-sensitive material 2 and maintaining the opacity of other heat-sensitive materials.

In fig. Figure 8 shows the layered structure of a device for recording exceeding threshold temperatures, the base 1 of which is made in the form of a clip, onto which heat-sensitive materials 2 are applied, covered with a transparent protective layer 4, which: (a) fits tightly to the base and materials and ensures the tightness of the device and the ability to maintain pressure below atmospheric; (b) fits tightly to the base and materials and has a gap 11a between the protective layer and the base; (c) fits tightly to the base and materials and has micro-holes 116 on its front surface.

Implementation of a utility model

General technology for manufacturing the device.

As the basis 1 of the claimed device, halogen-containing polymeric materials can be used, containing, in particular, copolymers of vinyl chloride, namely: copolymer C-15 (copolymer of vinyl chloride and vinyl acetate), copolymer VVD-40 (copolymer of vinyl chloride and vinylidene chloride), polyvinyl chloride (PVC ), cast PVC, as well as polyvinylidene fluoride PVDF, fluoroplastic M-40, as well as polyesters with additives of 6.5% hexabromocyclododecane or polyesters modified with 15% trichloroisopropyl phosphate. These materials have the necessary strength and flexibility, give the device fire resistance and have an electrical 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 electrical 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. Next, 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.

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

In some embodiments, the substrate may have reflective properties or may be colored using a substance that has luminescent properties to increase the visibility of both the device itself and the fact of its operation, which further increases the safety of operation of the equipment. Also, in special cases, the base can be painted to allow the claimed clip to be used for color marking of phases of electrical equipment.

In particular cases, the base can be colored using a substance designed to irreversibly change color when heated. The presence of an additional substance capable of irreversibly changing color when heated to a temperature below the threshold temperatures of the main heat-sensitive materials, in particular by 10-30°C, makes it possible to detect overheating of equipment that has not reached the maximum permissible values, and, as a result, to ensure the prevention occurrence of an emergency defect.

Also, the base can be colored using a substance capable of reversibly changing color when heated. For example, a layer of heat-sensitive paint having the above properties can be applied to the front surface. The presence of a substance capable of reversibly changing color when heated makes it possible to inform personnel not only about exceeding a threshold temperature in the past, but also about overheating at the time of inspection.

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

Preparation of heat-sensitive material.

Preferably, the solid phase of the at least one temperature-sensitive material includes an organic substance containing a C _n H _(2n+1) structural moiety, where n ≥ 5: aliphatic fatty acids containing a C _n H _(2n+1) structural moieties with n ≥ 12 ; salts of fatty aliphatic acids containing structural fragments C _n H _(2n+1) with n ≥ 5; alkanes containing at least 20 carbon atoms; dialkylphosphinic acids containing structural fragments C _n H _(2n+1) with n ≥ 5; amides of fatty aliphatic acids containing structural fragments C _n H _(2n+1) with n ≥ 5; aliphatic fatty acid anhydrides containing structural fragments C _n H _(2n+1) with n ≥ 10; fatty aliphatic alcohols containing structural fragments C _n H _(2n+1) with n ≥ 14; fatty aliphatic amines containing structural fragments C _n H _(2n+1) with n ≥ 17; nitriles of fatty aliphatic acids containing structural fragments C _n H _(2n+1) with n ≥ 19, for example, palmitic acid, stearic acid, behenic acid, tetracosane, erucamide, stearic alcohol, cetyl alcohol, polyethylene, wax, paraffin, saturated salts 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 crushed to a size of 2-3 microns in a ball mill, successively added a diluent or a solution of a binder in a diluent and stirred until smooth. The diluent can be used, for example, water, methanol, ethanol, isopropanol, ethylene glycol, ethylene glycol monomethyl ether, acetonitrile, etc., or mixtures thereof. The suspension was used for application immediately after receipt.

In preferred embodiments, the content of the at least one temperature-sensitive material of the solid phase, including organic matter, is not more than 50 wt.%, most preferably, not more than 70 wt.%.

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

In various embodiments, the substance that causes a change in the transparency of the heat-sensitive material when heated above the corresponding threshold temperature and is part of this 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, temperature threshold selected from the group: 50°С, 55°С, 60°С, 70°С, 80°С, 90°С, 100°С, 110°С, 120°С, 130°С, 140°С, 150°C.

For example, for a device containing three different temperature-sensitive materials, the threshold temperatures could be 50°C, 55°C, 60°C, that is, the first temperature-sensitive material changes transparency when it reaches 50°C, the second temperature-sensitive material changes transparency when it reaches 55 °C, and the third when the temperature reaches 60°C, in the range of no more than 5°C. In other embodiments, the threshold temperatures may be 50°C, 60°C, 70°C, or 50°C, 70°C, 80°C, or 60°C, 70°C, 80°C, or 60°C , 80°С, 100°С, or 60°С, 90°С, 110°С, or 70°С, 80°С, 90°С, or 70°С, 90°С, 110°С, or 70 °С, 100°С, 120°С, or 70°С, 110°С, 130°С, or 80°С, 90°С, 100°С, or 80°С, 120°С, 140°С, or 80°С, 120°С, 150°С, or 90°С, 100°С, 110°С, or 90°С, 110°С, 130°С, or 100°С, 120°С, 140° WITH.

For a device containing four different temperature sensitive materials, the threshold temperatures may be 50°C, 55°C, 60°C, 70°C, or 50°C, 60°C, 70°C, 80°C, or 50°C , 70°С, 90°С, 110°С, or 60°С, 70°С, 80°С, 90°С, or 60°С, 70°С, 80°С, 100°С, or 60° С, 80°С, 90°С, 110°С, or 70°С, 80°С, 90°С, 100°С, or 70°С, 90°С, 100°С, 120°С, or 70 °С, 90°С, 110°С, 130°С, or 80°С, 90°С, 100°С, 110°С, or 80°С, 100°С, 120°С, 140°С, or 80°C, 100°C, 120°C, 150°C.

To produce at least one heat-sensitive material, a solid phase, including a substance that causes a change in the transparency of the heat-sensitive material when heated above the corresponding threshold temperature, is ground in a ball mill to a size of 2-3 μm, and a liquid phase, represented by water or an organic solvent with a boiling point, is sequentially added 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 in which the solubility of the solid phase of the thermosensitive material does not exceed 10 g/kg.

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

The difference in density between the liquid phase and the solid phase is preferably less than 0.2 g/cm ³ . For 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.

In this production method, the at least one thermosensitive material produced is preferably present in 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, at least one obtained thermosensitive material in the initial state is opaque to at least part of visible light and in the initial state includes a solid phase and voids filled with a gas phase, the share of which in the initial state is at least 50 vol.%, and when heated above the corresponding threshold temperature, an irreversible change in the microstructure of the corresponding thermosensitive material occurs, accompanied by the fusion of particles of solid organic matter, a decrease in the proportion of voids, preferably 2 or more times, and an increase in its transparency with the appearance of the color of the base, and upon subsequent cooling to 20°C and exposure 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.

Depending on the nature of the solid phase and the substance causing the change in transparency of the at least one heat-sensitive material when heated above an appropriate threshold temperature, the form of the resulting solid phase particles may be grains, crystals, fibers, flakes or conglomerates of these particles.

In particular cases, at least one heat-sensitive material additionally contains a polymer binder that is transparent to at least part of visible light, the phase transition temperature of which is higher than the corresponding phase transition temperature of the organic substance of the solid phase. In this case, the ground solid phase is suspended in a solution of a binder that is transparent to at least part of the visible light in the liquid phase. In preferred embodiments of the utility model, the binder is present in the resulting heat-sensitive material in an amount of 1-30 wt.%, to ensure the effect of glazing particles of solid organic matter.

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, polyethyl ene, polypropylene, polystyrene, polyvinylidene fluoride, polytetrafluoroethylene , polyethersulfone, polyisoprene, polypropylene, polybutadiene, polyisobutylene, polyvinyl acetate, polymethacrylate, ethylcellulose, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polycaprolactone, polyethylene terephthalate resin, polybutylene terephthalate resin, polyamide resin, polyvinylidene fluoride, polyester, poly ether resins, hydroxyethylcellulose, methylcellulose, ethylcellulose, nitrocellulose, carboxymethylcellulose, gelatin, agar-agar, casein, gum arabic, polyvinyl alcohol, polyethylene oxide or mixtures thereof.

In some cases, an inscription with information about threshold temperatures was placed on the front side of the device. In special cases, in addition to threshold temperatures, information about the expiration date was also included. In one embodiment, a drawing can be applied to the surface of the base, intended for marking phases or components of electrical equipment, containing graphic, numerical or text information.

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

To obtain a microstructure of at least one applied thermosensitive material, including a solid phase and voids filled with a gas phase, the share of which in the initial state is at least 50 vol.%, and providing an irreversible change in appearance when a threshold temperature is reached, which is accompanied by the melting of solid particles phase, reducing the proportion of voids and increasing its transparency with the appearance of the color of the base, you can use, in particular, the following techniques at the previously disclosed stages of the method:

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

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

Removal of the liquid phase from the deposited layers of the corresponding suspension of solid phase particles in the liquid phase or from each layer separately can be carried out both at sub-atmospheric pressure and at atmospheric pressure, depending on the chosen method of manufacturing the device.

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

Layer-by-layer application of a suspension of a solid phase in a liquid phase can also provide the claimed device. In this case, after applying the heat-sensitive material, the device is dried by selecting the mode for removing the liquid phase from the applied suspension layers, 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 particles of the solid phase and a large proportion of voids filled with the gas phase, occurs layer by layer. Layer-by-layer deposition with exposure, preferably at room temperature, between approaches ensures the ordering of the solid phase particles as they are located on the device and the formation of a large proportion of voids, which predominantly form a continuous gas phase. If the particles of the solid phase are flakes, in order to achieve coverage with a minimum layer thickness, it is preferable to have them longitudinally “overlapping” based on a thermal indicator. In this case, the scales will be arranged like closed blinds and there will be only a thin layer of scales 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 sedimentation of the flakes and their packing in a thermodynamically favorable state is ensured. When this technique is used in the preparation of a thermosensitive material, a predominant formation of a continuous solid phase is observed, and the voids filled with gas form a continuous gas phase. When carrying out forced removal of the liquid phase from the applied layers of suspension during heating or when blowing with air, the kinetic processes of solvent evaporation will prevail over the thermodynamic ordering of particles of the solid phase, as a result of which the flakes will form not longitudinal, but transverse structures (the “open blinds principle”), through which the base will be visible at the same layer thickness, for which, subject to the principle of closed blinds, coverage will be achieved.

Such ordering can also be achieved through the use of a diluted appropriate suspension of solid phase particles in the liquid phase (dilution of more than 50%), since in a large volume the flakes will be oriented in the desired manner and settle in an ordered form, in contrast to the use of more concentrated suspensions. In addition, large dilution guarantees a longer process of spontaneous evaporation of the liquid phase, during which the flakes will also be laid according to the principle of closed blinds. Another factor influencing the rate and nature of sedimentation of solid phase particles is the relative difference in the densities of the solvent and solid phase particles. If there is a large difference in density (more than 0.2 g/cm ³ ), solid phase particles will settle out of the suspension too quickly according to the principle of open shutters. At comparable densities or with a difference in densities of less than 0.2 g/cm ^3, a 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 shutters.

Thus, adherence to the principle of closed shutters when forming the microstructure of at least one heat-sensitive material makes it possible to obtain a material whose microstructure in the initial state has a predominant orientation of solid phase particles parallel to the surface of the base and protective coating.

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

The effects described above apply to embodiments of the device in which the microstructure of at least one heat-sensitive material is represented by an organic substance, the particles of which are predominantly in the form of flakes, crystals or fibers, i.e. such 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 may be observed.

In the case of using at least one heat-sensitive material containing a solid phase, a binder and voids, a suspension of a finely dispersed solid phase in a solution of a binder in a 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. In this case, “glazing” occurs both of an individual particle of the solid phase and of the resulting conglomerate of particles.

When applying suspensions of solid phase particles in the liquid phase, the area of the front surface of the device base, which should not be touched by the first heat-sensitive material, is sealed with plastic film. A layer of the first suspension of solid phase particles in the liquid phase is uniformly applied to the uncovered area of the base using one of the techniques described above or other methods that ensure the formation of the described microstructure. After the layer has completely dried using one of the methods described above, the protective film is removed and the procedure for applying the second and subsequent suspensions of solid phase particles in the liquid phase is sequentially repeated to obtain several sections of heat-sensitive materials.

In advantageous embodiments, the thickness of the layer of at least one heat-sensitive material is no more than 800 microns, preferably no more than 450 microns, most preferably no more than 150 microns. The use of a specified layer thickness of at least one heat-sensitive material ensures that it responds at a rate of less than 5 seconds, preferably less than 2 seconds, when heated above a corresponding threshold temperature. This is due to the fact that this thickness of the material layer, in combination with the thickness of the base of the thermal indicator, allows the corresponding heat-sensitive material to be heated when short-term overheating occurs during peak load periods and completely transforms it into a melt with an “opaque-transparent” color transition in less than 5 seconds, and also provides the necessary heat transfer during air cooling of operating devices.

The front surface area of the base is from 3 mm ² , preferably at least 10 mm ² , and the surface area of the base covered with areas of heat-sensitive materials is from 3 to 97% of the front surface area of the base, preferably at least 30% of the front surface area of the base, which makes it possible to identify triggered devices from a long distance, and also allows you to identify spot heating of a large surface of installations.

In some variants of the utility model, black paint or an inscription is first applied to the unclosed area of the base using solvent dyes, including, in particular, the numerical value of the threshold temperature or other graphic, numerical or text information, and only then layers of heat-sensitive materials are applied. Moreover, in advantageous embodiments of the invention, at least 70% of the base area is covered with black paint. In the case of painting at least part of the base black, at least one heat-sensitive material in the initial state is white, and when heated above a threshold temperature, a visual color transition of at least part of the surface of the device "white-black" occurs.

It should be noted that the claimed utility model can use either one heat-sensitive material or several heat-sensitive materials with different threshold temperatures. The number of heat-sensitive materials is not limited by an upper limit, and depends on the practical task implemented when using the declared device (type of equipment, required step of the determined overheating temperature, area of the surface being tested for heating, etc.).

At the final stage of preparation, the temperature indicator was covered with a transparent protective layer. In some variants of the utility model, 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 leave the device after exceeding the recorded temperature. Preferably, the transparent protective layer is selected from transparent elastic polymers. In another variant of the utility model, the device blank is kept 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 a gas phase below atmospheric pressure. For this purpose, in this embodiment of the utility model, transparent elastic polymer films are also used as a protective layer.

In particular embodiments, at least one recess can be made in the base material of the clip, which is filled with at least one heat-sensitive material according to the above methods.

In preferred embodiments, the at least one heat-sensitive material is configured to detect local overheating of the surface by changing the color of only that part of the heat-sensitive material that was heated above the corresponding threshold temperature and maintaining the original color of the heat-sensitive material that was not heated above the threshold temperature, with uneven heating, as well as other heat-sensitive materials, the threshold temperature of which is higher than the threshold temperature of the first material.

After applying the heat-sensitive materials, the device is covered with an elastic protective film that is transparent to at least part of visible light, which protects the device from external environmental influences, humidity, UV irradiation and mechanical damage, increases the service life of the device and prevents heat-sensitive materials from draining during a phase transition . Thus, the device is configured to register the excess of several threshold temperatures of conductive elements in the open air.

In a particular case, the base 1, made in the form of a clip, 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 markings in field of electrical engineering. The color of the base 1 does not affect the visual registration of exceeding threshold temperatures of the surface of the equipment, but provides the marking of the device necessary to increase the overall safety of the operation of the equipment.

Also, in a particular case, a dye, including black, can be applied to the base, made in the form of a clip, in the area of at least one heat-sensitive material, before applying this heat-sensitive material. In one embodiment, at least 70% of the base area covered with heat-sensitive materials is painted black.

The principle of operation of the device.

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

A clip for recording exceeding threshold temperatures with applied heat-sensitive materials works as follows. Thermally sensitive materials 2 in the initial state and until heated to the appropriate threshold temperature are opaque to at least part of visible light and, in advantageous embodiments of the utility model, have a white color.

Until the entire surface of the clip or its individual sections located under the heat-sensitive materials 2 are heated to the threshold temperature of the first heat-sensitive material with a minimum threshold temperature Ti with a given accuracy, all heat-sensitive materials 2 remain opaque, thereby preserving the original appearance of the device. When the threshold temperature Ti is reached with the stated accuracy on the entire surface of the first thermosensitive material 2, or predominantly on the surface of the heated section 12 of the thermosensitive material 2, respectively, having a threshold temperature Ti, irreversible destruction of the microstructure of the thermosensitive material 2 occurs, accompanied by the fusion of particles of the solid phase 7, a decrease the proportion of voids 8 and, as a result, an increase in transparency. In this case, the apparent density of the material increases. A heat-sensitive material having a threshold temperature T ₁ 2 with a modified microstructure is transparent and displays the color of the base 1 under the material or the color of the paint 3 applied to the base in the area of the heat-sensitive material.

At the same time, other heat-sensitive materials that have threshold temperatures T _2…n > T ₁ do not undergo a change in transparency and retain their original appearance. A further increase in the temperature of the surface on which the clip is placed to temperature T _2...n will lead to sequential activation of all areas with heat-sensitive materials with threshold temperatures T _2...n . Moreover, if the maximum heating temperature of the clip is lower than at least one of the threshold temperatures of heat-sensitive materials _Tn , then the corresponding areas of heat-sensitive materials _Tn will remain opaque. Upon subsequent cooling of the controlled surface, the triggered 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 irreversible visual registration of temperature exceeding the threshold temperature value, both at the moment of overheating and after a long time.

When repeated overheating of the controlled surface occurs to the threshold temperatures of previously unworked areas with heat-sensitive materials T _n with a given accuracy, irreversible destruction of the microstructure of the corresponding heat-sensitive materials 2 occurs, accompanied by the fusion of particles of the solid phase 7, a decrease in the proportion of voids 8, an increase in the apparent density of the material and, as a consequence , increasing transparency.

When spot heating a controlled surface, a transparent zone 12 is formed only in that area of the corresponding heat-sensitive material that was subjected to heating above the corresponding threshold temperature, while maintaining an opaque region of the material in its remaining zone that was not subject to heating.

At least one numerical value of the threshold temperatures 4 can be applied to the front side of the base 1; in particular cases, the value of the threshold temperatures can be applied in an area free from the corresponding heat-sensitive material 2, but next to it, or on the base 1 under the corresponding heat-sensitive material 2. In the latter case, when the temperature exceeds a threshold value corresponding to at least one heat-sensitive material, after an irreversible change in the microstructure of this heat-sensitive material 2, the color of the base 1 and the corresponding numerical value of the threshold temperature 4 appear. In particular embodiments, the base can be black and the at least one heat-sensitive material may be white in its initial opaque state. In this case, after the temperature exceeds the threshold value, a change in the appearance of the thermal indicator is observed with a maximum “white-black” contrast, which additionally ensures the visibility of the triggered thermal indicator and facilitates its visual identification. A similar purpose is achieved by the implementation of a thermal indicator, in which the base has a color other than black, and in the area under at least one heat-sensitive material 2, which is white in the initial state, black paint is applied. In this case, also when the thermal indicator a is triggered, a “white-black” color transition is observed in at least part of the device.

In the case of a thermal indicator hermetically coated 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 at least one heat-sensitive material 2 and the delamination of gas and non-gas environments, a bubble will form on the surface of the protective layer 5, which decreases as the device cools. When using a thermal indicator with a sealed protective layer 5 and a pressure inside the voids 8 of the thermosensitive material 2 below atmospheric pressure, the formation of a bubble on the surface of the protective layer 5 will not be observed when at least one threshold temperature is exceeded, due to the fact that the pressure of the gas phase inside the voids 8 created at stage of obtaining a thermal indicator blank when applying a protective layer 5, in the initial state below atmospheric and compensates for the thermal expansion of the gas released when the microstructure of the thermally sensitive material 2 is destroyed. In other embodiments of the thermal indicator, to prevent the occurrence of a bubble when the threshold temperature is exceeded between the transparent protective layer and the base, it can be a gap 11a is made or micro-holes 116 can be made in the protective layer, allowing the gas released during activation to escape.

Versions of the clip, in which the composition of at least one heat-sensitive material 2 includes particles of the solid phase 7, voids 8 and a binder 10, have a similar operating principle. When the temperature exceeds at least one threshold value, the fusion of particles 7, “glazed” with the binder 10, occurs with the release of the gas phase and the separation of gas and non-gas environments, which also results in irreversible destruction of the microstructure of the thermosensitive material 2, accompanied by a decrease in the proportion of voids 8 and , as a consequence, increasing the transparency of the corresponding material.

Thus, all versions of the thermal indicator have an operating principle based on the irreversible destruction of the microstructure of at least one heat-sensitive material 2, accompanied by the fusion of particles of the solid phase 7, a decrease in the proportion of voids 8 and, as a consequence, an increase in the transparency of the corresponding material and an irreversible change in the appearance of the thermal indicator . Moreover, when cooled, the thermal indicator a does not return to its original state; preferably, the transparency of at least one activated heat-sensitive material does not decrease to its original values when cooled to 20°C and held at this temperature for at least one month, preferably one year and more.

Thus, during a visual inspection of the temperature indicator, it can reliably and with high accuracy (in the range of +/-5°C, mainly +1-2°C, relative to the threshold temperature indicated on the temperature indicator) and speed (no more than 5 seconds, mainly no more than 2 seconds) to register the fact that the temperature of the entire surface or its local area exceeds at least one threshold value.

Below are preferred embodiments of the claimed thermal indicator, which are illustrative and do not in any way limit the scope of the requested legal protection.

Examples

Example 1. General technology for manufacturing the device

Preparation of thermosensitive material: 100 g of an organic substance with a phase transition temperature corresponding to the threshold registration temperature in the range of 5 ° C, crushed to a size of 2-3 microns, 300 g of a 3-33% binder solution in water, methanol, ethanol, isopropanol, ethylene glycol, ethylene glycol monomethyl ether, acetonitrile or mixtures thereof and stirred until smooth. The suspension was immediately used to apply the composition.

For examples, as one of the possible embodiments of the device, halogen-containing polymer bases of various colors were selected, with fire resistance and an electrical strength of at least 5 kV/mm, as well as elasticity that allows them to be placed on electrical wires, preferably with a diameter of 1 to 10 mm without additional fastening elements.

In particular cases, an information element containing the values of threshold operating temperatures in degrees Celsius was applied to a base made in the form of a clip using solvent dyes. Then the area where the first heat-sensitive material should not fall was sealed with a protective polyethylene film and the first 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 not higher than the operating temperature of the composition for at least three hours, or for 24 hours at room temperature. After the layer had completely dried, the protective film was removed and the procedure for applying the second and subsequent heat-sensitive materials was sequentially repeated. In the initial state, all heat-sensitive materials are white. The device was covered with a transparent elastic protective film.

Example 2.

Yttrium behenate with a phase transition temperature of 90°C, lanthanum palmitate with a phase transition temperature of 100°C, and lanthanum nonadecynate with a phase transition temperature of 110°C were used as organic substances for the preparation of thermosensitive materials in Example 1. The suspensions were applied by silk-screen printing onto a base made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, with a thickness in the area of heat-sensitive materials of 0.5 mm, according to the method described in example 1, and the numerical values of threshold temperatures were applied in the zones free from heat sensitive materials. After the layer had completely dried, the protective film was removed and the procedure for applying the second and subsequent heat-sensitive materials was sequentially repeated. The number of layers of heat-sensitive materials was 7; between applications, the compositions were dried in a vacuum chamber at 100 mmHg and 20°C for one hour. The thickness of the layers of all heat-sensitive materials was 0.6 mm, their total 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.

The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then controlledly heated at a speed of 5°C/min to a temperature of 90°C with a given accuracy and the fact of activation of the corresponding zone of the device was recorded by visually recording the increase in the transparency of the heat-sensitive material with the appearance of the color of the base . Next, the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 100°C with a given accuracy, the fact that another corresponding zone of the device was activated in a similar way was recorded, then the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 110°C with a given accuracy and recorded the fact of activation of the third corresponding zone of the device. The time during which the phase transition occurred and the change in transparency of the first heat-sensitive material was 1 second, the second heat-sensitive material was 2 seconds, and the third heat-sensitive material was 1 second. After cooling the device to room temperature, the preservation of transparency of all zones with temperature-sensitive materials was visually recorded. During heating and after cooling, it was revealed that the device remained tightly fixed to the surface of the heating element.

Example 3.

Tetracosane with a phase transition temperature of 50°C, ytterbium caprylate with a phase transition temperature of 60°C, eicosanoic acid with a phase transition temperature of 70°C and dioctylphosphinic acid with a phase transition temperature of 80°C were used as organic substances for the preparation of thermosensitive materials according to example 1 . The suspensions were applied by silk-screen printing onto 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 heat-sensitive materials of 0.7 mm, according to the method described in example 1, and numerical values of threshold temperatures were applied in the zones heat-sensitive materials before their application, and in areas free of heat-sensitive materials, information about the service life is printed. After the layer had completely dried, the protective film was removed and the procedure for applying the second and subsequent heat-sensitive materials was sequentially repeated. The number of layers of heat-sensitive materials was 7; between applications, the compositions were dried in a thermostat at a temperature of 40°C for three hours. The thickness of the layers of all heat-sensitive materials was 0.8 mm, their total area was 97% of the area of the front surface of the sticker. The device was covered with a transparent protective film made of polyvinyl chloride, 0.1 mm thick.

The clip was installed at room temperature on a cylindrical heating element with a diameter of 5 mm, which was then controlledly heated at a speed of 5°C/min to a temperature of 50°C with a given accuracy and the fact of activation of the corresponding zone of the device was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the color of the base . Next, the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 60°C with a given accuracy, the fact that another corresponding zone of the device was activated in a similar way was recorded, then the heating element was immediately heated in a controlled manner at a speed of 5°C/min to a temperature of 70°C with a given accuracy, the fact of activation of the third corresponding zone of the device was recorded, then the heating element was immediately heated in a controlled manner at a speed of 5°C/min to a temperature of 80°C with a given accuracy, and the fact of activation of the fourth corresponding zone of the device was recorded. The time during which the phase transition occurred and the change in transparency of the first heat-sensitive material was 3 seconds, the second heat-sensitive material was 4 seconds, the third heat-sensitive material was 4 seconds, and the fourth heat-sensitive material was 3 seconds. After cooling the device to room temperature, the preservation of transparency of all zones with temperature-sensitive materials was visually recorded. During heating and after cooling, it was revealed that the device remained tightly fixed to the surface of the cylindrical heating element.

Example 4.

Lanthanum capronate with a phase transition temperature of 120°C, zinc nonadecanoate with a phase transition temperature of 130°C, and zinc palmitate with a phase transition temperature of 140°C were used as organic substances for the preparation of thermosensitive materials in Example 1. The suspensions were applied by silk-screen printing onto a base made in the form of a clip without additional fastening elements made of a copolymer of vinyl chloride and vinyl acetate of red color, with a thickness in the area of heat-sensitive materials of 0.2 mm, according to the method described in example 1, and in areas of heat-sensitive materials before their application numerical values of threshold temperatures were applied, as well as black paint. After the layer had completely dried, the protective film was removed and the procedure for applying the second and subsequent heat-sensitive materials was sequentially repeated. The number of layers of heat-sensitive materials was 5; between applications, the composition was dried for 24 hours at room temperature. The thickness of the layers of all heat-sensitive materials was 0.2 mm, their total area was 70% of the area of the front surface of the sticker. The device was covered with a transparent protective film made of polyurethane modified with 15% trichloroisopropyl phosphate, 0.5 mm thick.

The clip was installed at room temperature on a cylindrical heating element with a diameter of 10 mm, which was then heated in a controlled manner at a speed of 5°C/min to a temperature of 120°C with a given accuracy, the heating was stopped and the fact of activation of the corresponding zone of the device was recorded by visually recording the increase in the transparency of the heat-sensitive material with manifestation of the color of the base underneath. The time during which the phase transition occurred and the transparency of the first temperature-sensitive material changed was 1 second. After subsequent cooling of the device to room temperature, it was visually recorded that the device retained its appearance and the transparency of the heat-sensitive material did not return to its original state. Cycles of heating to temperatures of 130°C and 140°C and subsequent cooling to room temperature were repeated. After each cycle, the change in transparency of the corresponding zone of the thermosensitive material was recorded. The time during which the phase transition occurred and the transparency of the second and third heat-sensitive materials changed was 1 second. After the final cooling of the device to room temperature, the preservation of transparency of all zones with temperature-sensitive materials was visually recorded. During heating and after cooling, it was revealed that the device remained tightly fixed to the surface of the cylindrical heating element.

Example 5.

Yttrium capronate with a phase transition temperature of 55°C, zinc capronate with a phase transition temperature of 150°C, and lithium stearate with a phase transition temperature of 210°C were used as organic substances for the preparation of thermosensitive materials according to example 1. The suspensions were applied by silk-screen printing onto 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 reflective properties, having a thickness in the area of heat-sensitive materials of 0.35 mm, according to the method described in example 1, and in areas of heat-sensitive materials Before applying the materials, numerical values of threshold temperatures were applied, as well as black paint. After the layer had completely dried, the protective film was removed and the procedure for applying the second and subsequent heat-sensitive materials was sequentially repeated. The number of layers of heat-sensitive materials was 5; between applications, the compositions were dried in a vacuum chamber at 100 mmHg and 20°C for one hour. The thickness of the layers of all heat-sensitive materials was 0.4 mm, their total area was 3% of the area of the front surface of the sticker. The device was covered with a transparent protective film made of PVC, 0.25 mm thick.

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 speed of 5°C/min to a temperature of 55°C with a given accuracy and the fact of activation of the corresponding zone of the device was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the color of the base . Next, the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 150°C with a given accuracy, the fact that another corresponding zone of the device was activated in a similar way was recorded, then the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 210°C with a given accuracy and recorded the fact of activation of the third corresponding zone of the device. After cooling the device to room temperature, the preservation of transparency of all zones with temperature-sensitive materials was visually recorded. During heating and after cooling, it was revealed that the device remained tightly fixed to the surface of the cylindrical heating element.

Example 6.

n-hexadecyl-n-pentylhydrogen phosphate with a phase transition temperature of 40°C, palmitic acid anhydride with a phase transition temperature of 60°C, and erucamide with a phase transition temperature of 80°C were used as organic substances for the preparation of thermosensitive materials in example 1. The suspensions were 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 of 0.15 mm in the area of heat-sensitive materials, according to the method described in example 1, and in areas of heat-sensitive materials Before applying them, numerical values of threshold temperatures were applied, as well as black paint. After the layer had completely dried, the protective film was removed and the procedure for applying the second and subsequent heat-sensitive materials was sequentially repeated. The number of layers of heat-sensitive materials was 5; between applications, the compositions were dried in a thermostat at a temperature of 70°C for three hours. The thickness of the layers of all heat-sensitive materials was 0.2 mm, their total area was 30% of the area of the front surface of the sticker. 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 speed of 5°C/min to a temperature of 40°C with a given accuracy and the fact of activation of the corresponding zone of the device was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the color of the base . Next, the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 60°C with a given accuracy, the fact that another corresponding zone of the device was activated in a similar way was recorded, then the heating element was immediately heated in a controlled manner at a speed of 5°C/min to a temperature of 80°C with a given accuracy and recorded the fact of activation of the third corresponding zone of the device. After cooling the device to room temperature, the preservation of transparency of all zones with temperature-sensitive materials was visually recorded. During heating and after cooling, it was revealed that the device remained tightly fixed to the surface of the cylindrical heating element.

Example 7.

1-tetradecanol with a phase transition temperature of 40°C, docosannitrile with a phase transition temperature of 55°C, and n-docosylamine with a phase transition temperature of 65°C were used as organic substances for the preparation of thermosensitive materials according to Example 1. The suspensions were applied by silk-screen printing onto 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, and in the areas of heat-sensitive materials, numerical values of threshold temperatures, as well as black paint, were applied before their application. After the layer had completely dried, the protective film was removed and the procedure for applying the second and subsequent heat-sensitive materials was sequentially repeated. The number of layers of heat-sensitive materials was 6; between applications, the compositions were dried for 24 hours at room temperature. The thickness of the layers of all heat-sensitive materials was 0.5 mm, their total area was 30% of the area of the front surface of the sticker. The device was covered with a transparent protective film made of PVC, 0.35 mm thick.

The clip was installed at room temperature on a cylindrical heating element with a diameter of 1 mm, which was then controlledly heated at a speed of 5°C/min to a temperature of 40°C with a given accuracy and the fact of activation of the corresponding zone of the device was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the color of the base . Next, the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 55°C with a given accuracy, the fact that another corresponding zone of the device was activated in a similar way was recorded, then the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 65°C with a given accuracy and recorded the fact of activation of the third corresponding zone of the device. After cooling the device to room temperature, the preservation of transparency of all zones with temperature-sensitive materials was visually recorded. During heating and after cooling, it was revealed that the device remained tightly fixed to the surface of the cylindrical heating element.

Example 8.

The area of the base, made in the form of a clip without additional fastening elements made of black Oramask 831 PVC, on which heat-sensitive materials will be applied, was sealed with a protective polyethylene film, the free area was covered with pigmented yellow Tempilaq reversible thermal paint with a color change temperature of 113°C. After the paint had dried, the protective polyethylene film was removed and numerical values of threshold temperatures were applied to the surface of the base containing thermal paint using solvent dyes. Then a protective polyethylene film was glued to the area that should not be touched by the first heat-sensitive material, and a suspension with the first heat-sensitive material was applied using silk-screen printing. After the layer had completely dried, the protective film was removed and the procedure for applying the second and subsequent heat-sensitive materials was sequentially repeated. The number of layers of heat-sensitive materials was 5; between applications, the compositions were dried in a thermostat at a temperature of 60°C for three hours. The thickness of the base containing thermal paint was 0.45 mm. Yttrium behenate with a phase transition temperature of 90°C, lanthanum palmitate with a phase transition temperature of 100°C, and lanthanum nonadecynate with a phase transition temperature of 110°C were used as organic substances for the preparation of thermosensitive materials in Example 1. The thickness of the layers of all heat-sensitive materials was 0.6 mm, their total area was 30% of the area of the front surface of the device. In the initial state, the zones of heat-sensitive materials are white. The device was covered with a transparent elastic 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 1 mm, which was then heated in a controlled manner at a speed of 5°C/min to a temperature of 90°C with a given accuracy and the fact of activation of the corresponding zone of the device was recorded by visually recording an increase in the transparency of the heat-sensitive material with the appearance of the color of the base . Next, the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 100°C with a given accuracy, the fact that another corresponding zone of the device was activated in a similar way was recorded, then the heating element was immediately heated in a controlled manner at a rate of 5°C/min to a temperature of 115°C with a given accuracy and recorded the fact of activation of the third corresponding zone of the device, as well as the fact of operation of thermal paint with the appearance of the color of the base. The time during which the phase transition occurred and the change in transparency of the first heat-sensitive material was 1 second, the second heat-sensitive material was 2 seconds, and the third heat-sensitive material was 1 second. After cooling the device to room temperature, the preservation of the transparency of all zones with heat-sensitive materials and the return of the thermal paint to its original color were visually recorded. During heating and after cooling, it was revealed that the device remained tightly fixed on the surface of the cylindrical heating element and did not come off.

Example 9.

The area of the base, made in the form of a clip without additional fastening elements made of Oramask 831 black PVC, on which heat-sensitive materials will be applied, was sealed with a protective polyethylene film, the free area was covered with pigmented yellow thermal paint Hallcrest SC with a temperature of irreversible color change of 80°C. After the paint had dried, the protective polyethylene film was removed and numerical values of threshold temperatures were applied to the surface of the base containing thermal paint using solvent dyes. Then a protective polyethylene film was glued to the area that should not be touched by the first heat-sensitive material, and a suspension with the first heat-sensitive material was applied using silk-screen printing. After the layer had completely dried, the protective film was removed and the procedure for applying the second heat-sensitive material was sequentially repeated. The number of layers of heat-sensitive materials was 5; between applications, the compositions were dried in a thermostat at a temperature of 60°C for three hours. The thickness of the base containing thermal paint was 0.45 mm. Zinc nonadecanoate with a phase transition temperature of 130°C and zinc capronate with a phase transition temperature of 150°C were used as organic substances for the preparation of thermosensitive materials according to example 1. The thickness of the layers of all heat-sensitive materials was 0.6 mm, their total area was 30% of the area of the front surface of the device. In the initial state, the zones of heat-sensitive materials are white. The device was covered with a transparent elastic protective film made of PVC, 0.05 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 speed of 5°C/min to a temperature of 80°C with a given accuracy, and the fact that the thermal paint was activated with a color change was recorded. Then heating was continued to a temperature of 150°C and the facts of activation of zones of heat-sensitive materials of the device with the appearance of the color of the base were successively recorded. The time during which the phase transition occurred and the change in transparency of the first heat-sensitive material was 2 seconds, and the second heat-sensitive material was 1 second. After cooling the device to room temperature, the preservation of the transparency of the zones of heat-sensitive materials, as well as the preservation of the changed color of the thermal paint, was visually recorded. During heating and after cooling, it was revealed that the device remained tightly fixed to the surface of the heating element.

These examples do not limit the claimed utility model, however, they clearly reveal special cases of the implementation of the claimed utility model, and also confirm the achievement of a technical result related to ensuring increased safety of operation of electrical equipment due to the rapid, reliable and reliable detection of defects associated with excessive heating through irreversible registration of the fact that an element of electrical equipment exceeds specified threshold temperatures, a device that is conveniently and reliably mounted on wires and other elements of electrical equipment.

The utility model has been disclosed above with reference to a specific embodiment thereof. For specialists, other embodiments of the utility model may be obvious, without changing its essence, as it is disclosed in the present description. Accordingly, the utility model should be considered not limited in scope by the given description and examples.

Claims (21)

1. A device for recording exceeding threshold temperatures, including a base that is opaque to at least part of visible light, made in the form of a clip made of elastic material, designed to be installed on wires and contact connections of electrical equipment, partially coated on the front side with various heat-sensitive materials, each of which are designed with the ability to irreversibly change transparency relative to the initial state when heated to the corresponding threshold temperature. 2. The device according to claim 1, in which the base is elastic and includes halogen-containing polymers, preferably containing a structural unit -CH ₂ CHCl-, preferably polyvinyl chloride, preferably cast polyvinyl chloride. 3. The device according to claim 1, characterized in that the base is made in the form of a single structure with the ability to be fixed to 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 contains elements for snapping the device onto electrical wires, preferably with a diameter of 1 to 10 mm. 5. The device according to claim 1, characterized in that the area of the front surface of the base is from 3 mm ² , preferably at least 10 mm ² . 6. The device according to claim 1, characterized in that the heat-sensitive materials are located in recesses made in the material from which the base of the clip is made. 7. The device of claim 1, wherein the heat-sensitive materials are covered with an elastic protective film, transparent to at least part of visible light, preferably made of polyvinyl chloride, most preferably cast polyvinyl chloride. 8. The device according to claim 1, in which the heat-sensitive materials in the initial state are painted white, and when the transparency of the heat-sensitive materials changes, a visual color transition from white to black occurs. 9. The device according to claim 1, characterized in that the heat-sensitive materials irreversibly change their transparency when heated in a range not exceeding 5°C, preferably not exceeding 2°C relative to the corresponding threshold temperatures. 10. The device according to claim 1, in which at least one heat-sensitive material in the initial state has a microstructure that includes a solid phase and voids forming a continuous gas phase, the proportion of which is at least 50 vol.%, and is designed to irreversibly change its appearance upon reaching the corresponding threshold temperature due to the destruction of the microstructure of the thermosensitive material, accompanied by the fusion of solid phase particles, a decrease in the proportion of voids and an increase in its transparency with the appearance of the color of the base. 11. The device according to claim 10, in which the solid phase of at least one heat-sensitive material includes an organic substance containing a structural fragment C _n H _(2n+1) , where n≥5. 12. The device according to claim 10, in which the solid phase of at least one heat-sensitive material includes an organic substance that is selected from the group: aliphatic fatty acids containing structural fragments C _n H _(2n+1) with n≥12; salts of fatty aliphatic acids containing structural fragments C _n H _(2n+1) with n≥5; alkanes containing at least 20 carbon atoms; dialkylphosphinic acids containing structural fragments C _n H _(2n+1) with n≥5; amides of aliphatic fatty acids containing structural fragments C _n H _(2n+1) with n≥5; aliphatic fatty acid anhydrides containing structural fragments C _n H _(2n+1) with n≥10; fatty aliphatic alcohols containing structural fragments C _n H _(2n+1) with n≥14; fatty aliphatic amines containing structural fragments C _n H _(2n+1) with n≥17; nitriles of fatty aliphatic acids containing structural fragments C _n H _(2n+1) with n≥19, preferably selected from the group: palmitic acid, stearic acid, behenic acid, tetracosane, erucamide, stearic 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 claim 11, in which the mass content of the solid phase in at least one heat-sensitive material is at least 50 wt.%, and at least one heat-sensitive material contains a polymer binder transparent to at least part of the visible light in an amount 1-30 wt.%. 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, in which the heat-sensitive materials are configured to change transparency when heated to a temperature above their corresponding threshold within no more than 5 seconds, preferably no more than 2 seconds. 16. The device according to claim 1, characterized in that it can be used for color marking of phases of electrical equipment due to the color of the base. 17. The device according to claim 1, in which the surface area of the base covered with areas of heat-sensitive materials is from 3 to 97% of the front surface area of the base, preferably at least 30% of the front surface area of the base. 18. The device according to claim 1, in which the base has reflective properties or is colored using a substance having luminescent properties. 19. The device of claim 1, wherein the substrate is at least partially colored using a substance capable of changing color reversibly or irreversibly when heated. 20. The device according to claim 1, in which the thickness of the base in areas of heat-sensitive materials 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.