RU2749203C1 - Infrared camouflage - Google Patents

Abstract

FIELD: information protection.SUBSTANCE: invention relates to information protection means, more specifically to shielding devices that absorb electromagnetic radiation in the spectrum of near infrared range of wavelengths. Infrared camouflage is made of stacked segments joined by a valve method, each of which consists of three sequential layers tied together: (1) fiberglass fabric of the “E” mark with a coating of metallized polyester resin of 25 mcm, facing towards the concealed object; (2) heat-insulating needle-punched mat based on 100% aluminum-borosilicate glass with a thickness of 4 to 25 mm; (3) fiberglass fabric of the “E” mark with a double-sided silicone coating.EFFECT: technical result is increased protection of the concealed object from detection in the infrared frequency range.3 cl, 7 dwg, 3 tbl

Description

Technology area

The present invention relates to information security means, more specifically, to shielding means that absorb electromagnetic radiation in the near-infrared wavelength range.

State of the art

To protect objects from means of detection in the prior art, a wide range of methods is used (see.Technical means and methods of information protection: Textbook for universities / A.P. Zaitsev, A.A. Shelupanov, R.V. Meshcheryakov, etc.; ed. A.P. Zaitsev and A.A.Shelupanov. - M .: Publishing House Mashinostroenie, 2009 - 508 p.).

Thus, it is known that unmasking features of objects in the infrared range of the electromagnetic spectrum include: intrinsic (natural) radiation of heated bodies and reflected (artificial) IR radiation by objects. Target detection is possible due to differences in the thermal emissivity of the object and the background. At the same time, natural sources of PC radiation create background radiation, which makes it difficult to recognize objects. Natural sources of infrared radiation are on earth (soil, forest, etc.), atmospheric (clouds, atmospheric gases) and space (sun, moon, stars).

Thus, minimizing the differences between the PC-radiation of the object and the background, in particular, ground-based natural sources, makes it possible to increase the level of protection of the covered object from infrared detection means.

A review of the prior art shows the prominence of means for shielding infrared radiation.

For example, a reflective material is known, consisting of several layers, bonded by a needle-punched method (RU 2692274 C1, 24.06.2019). The disadvantage of the known material is its low heat reflectance (about 40%). In addition, the known solution is intended to create thermal protection for a person and does not minimize the difference between the radiation of the object and the radiation of the background, i.e. cannot be used as a means of masking objects.

The solution known from (EA 201800485 A1, 08/30/2019), a heat-absorbing coating made of multilayer, can be referred to a solution that is closer to the essence of the proposed invention. In the known solution, the laminating shells are made of fiberglass in a layer. The disadvantages of the known solution include the complexity of the design. Despite its purpose, the solution provides a decrease in the contrast of the probed object in relation to the background only in the 8-12 GHz range, which does not correspond to the IR range.

The proposed invention is aimed at overcoming the disadvantages of the prior art and provides the achievement of the main technical result, which consists in increasing the protection of the sheltered object from detection in the infrared frequency range.

Disclosure of invention

To achieve the specified technical result, an infrared camouflage is proposed, made of type-setting segments, joined by a valve method, each of which consists of successive layers bonded to each other, the first of which is E-grade fiberglass coated with a metallized polyester resin of 25 microns, facing towards the sheltered object, a heat-insulating needle-punched mat based on 100% aluminoborosilicate glass with a thickness of 4 to 25 mm was used as the second layer, and E grade glass fabric with a double-sided silicone coating was used as the third outer layer.

In an additional embodiment of the invention, the layers are sewn with non-combustible metallized threads while the seams are treated with silicone glue.

In another additional embodiment of the invention, a color masking image in the form of a deformation mask is additionally applied to the outer camouflage layer.

The following section of the description presents information showing how it is possible to carry out the invention with the achievement of the specified, as well as other following technical results for a specialist.

Implementation of the invention

A preferred embodiment of the invention is presented below.

For a more complete disclosure of the essence of the invention is illustrated by the explanatory drawings, which show:

fig. 1 - complex design;

fig. 2 is a cross-sectional view of a heat-reflecting coating;

fig. 3-4 - temperature measurement;

fig. 5-7 - experimental results.

FIG. 1 shows an embodiment in which a vehicle is used as the object. The heat-reflecting coating is placed on a frame made of anodized aluminum structural section. The dimensions of the profile correspond to the dimensions of the vehicle with the formation of an air gap. At the same time, ensuring scalability and unification, the camouflage is made of type-setting (modular) segments that allow you to adapt (unify) the camouflage to the size of the covered object. Joining of the segments is performed by a tab (valve) method, which avoids the transfer of thermal energy. On the outer layer of camouflage, a color masking image is additionally applied in the form of a deformation mask (City, Forest / Field, Desert, etc.), which, due to the species distortion, ensures the complexity of masking.

Structurally, infrared camouflage is made of a heat-reflecting coating (TOC), consisting of heat-reflecting (insulating) materials with a mandatory air gap between the covered object and the camouflage material.

A general sectional view is shown in Figure 2, where under the corresponding positions are designated: 1 - reflective material; 2 - heat-insulating needle-punched mat; 3 - fiberglass with double-sided silicone coating.

The reflective material of the first layer is “E” grade glass fabric coated with a metallized polyester resin of 25 microns, facing towards the covered (masked) object.

Requirements for E-grade fiberglass fibers are known, for example, from ASTM D578-98.

Coating of glass fabric with metallized polyester resin 25 microns allows to reflect up to 90% of the object's PC radiation, providing protection against prolonged exposure to high temperatures. On the reverse side of the material, a silicone impregnation is applied, which makes the material resistant to wear, gas and vapor impermeability.

The physical characteristics of the first layer of the material are presented in Table 1.

As a second layer (filler) in camouflage, a heat-insulating needle-punched mat based on 100% aluminoborosilicate glass is used.

Depending on the power of the radiation source, the design varies from 4 mm to 25 mm.

This insulating material is frost-resistant, temperature-resistant, has low thermal conductivity and high resistance to the influence of steam, oil, water, does not change its properties and qualities during transportation and operation.

The physical characteristics of the second layer of material are presented in Table 2.

As the third (outer) layer in camouflage, E-grade fiberglass is used, with a double-sided silicone coating, which provides mechanical strength and resistance to environmental influences, diluted acids, alkalis, sparks and metal splashes. In accordance with GOST 30244-94, glass cloth of the “E” grade belongs to the G1 group in terms of flammability, in accordance with GOST 30402-96 it belongs to the B1 flammability group, according to the fire and explosion hazard requirements, it corresponds to GOST 121.044-89.

The physical characteristics of double-sided silicone coated fiberglass are shown in Table 3.

Due to the identical thermal conductivity of the material to dry soil, the effect of averaging the thermogram with the surrounding infrared background of the terrain is achieved.

In order to preserve the integrity of the camouflage under external influences, including elevated temperature and exposure to an open flame, the manufacturing technology of the product construct is carried out by sewing layers with non-combustible metallized threads with simultaneous processing of the seams with silicone glue to give them a seal.

Considering that textile materials have high porosity, a relatively small contact area between individual fibers and differ little in thermal conductivity, their thermal conductivity is determined to a large extent by the thermal conductivity of air in closed pores and convection through open pores. With an increase in the porosity of the structure to a certain limit, the thermal conductivity of textile materials decreases, since the thermal conductivity of air is lower than the thermal conductivity of the fibers. However, with a further increase in porosity, when open through pores appear, the thermal conductivity of materials increases, since convection begins to play an important role.

Taking this into account, an important value for confirming the implementation of the task is to conduct a full-scale experiment confirming the reflective, heat-insulating non-combustible properties of the material.

During the experiment, a sample of a multilayer heat-reflecting (insulating) material with a size of 200 × 200 mm, made according to the above description, was taken as an experimental sample.

By applying heat to one side of the material using a hot air gun, the heat patch was monitored with a Testo 865 Thermal Imager (FIG. 3). The spot temperature on the surface of the thermal contact was 136 ° C.

Simultaneously with this, the temperature was measured from the reverse side of the product (Fig. 4). The temperature on the back surface is 31.6 ° C.

With the duration of the heat exposure, the thermogram clearly shows the heating of one layer of glass fiber, the temperature of which during the exposure time t = 10 min rose to 120 ° C. Convection was also observed at the pierced seam, the seam temperature on the thermogram was 56.4 ° C.

The temperature of the general background of TOC during prolonged thermal exposure at 136 ° С did not rise above 32 ° С. The background temperature was 23 ° C. The temperature difference between the background of the thermogram and the test object was 9 ° C.

This is sufficient for averaging the thermogram with the surrounding infrared background, i. E. providing masking of the covered object.

Additionally, a full-scale experiment was carried out with the vehicle sheltering on the ground (Figs. 5-7).

FIG. 5 positions indicate: a - the temperature on the surface of the camouflage PC is 3.5 ° С, b - the vehicle temperature is 47 ° С (the vehicle is located outside).

FIG. 6, the position indicates: c - surface temperature with the car inside 4.2 ° C.

FIG. 6 positions indicate: d - surface temperature inside the structure 29.8 ° C.

Thus, the experimental results confirm the effectiveness of the application of the proposed invention for hiding (distorting) the thermal signature of the covered object and providing an average thermogram with the surrounding infrared background of the terrain.

Claims (3)

1. Infrared camouflage made of type-setting segments joined by a valve method, each of which consists of successive layers bonded to each other, the first of which is E-grade glass fabric coated with a metallized polyester resin of 25 microns, facing towards the object to be covered , as the second layer, we used a heat-insulating needle-punched mat based on 100% aluminoborosilicate glass with a thickness of 4 to 25 mm, and as the third outer layer we used E grade fiberglass with a double-sided silicone coating. 2. Infrared camouflage according to claim 1, characterized in that the layers are sewn with non-combustible metallized threads with simultaneous treatment of the seams with silicone glue. 3. Infrared camouflage according to any one of paragraphs. 1 or 2, characterized in that a color masking image in the form of a deformation mask is additionally applied to the outer layer

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