RU196433U1 - Thermal protection device for heat-generating electro-radio products - Google Patents

Abstract

The proposed utility model relates to thermal protection devices that use the latent heat of the phase transition of a heat-accumulating substance, which is used to ensure the temperature regime of operation of heat-generating electric radio products (ERI) during cyclic operation and protection against short-term external thermal influences. A thermal protection device for heat-generating radio electronic devices is claimed, which comprises a body with a cover made of metal, the internal surfaces of the body forming a cavity, the internal volume of the cavity being filled with phase-transfer heat-accumulating material and sheet pyrolytic graphite material. In turn, the casing is equipped with at least one hole for mounting on a printed circuit board, and the side walls or the base of the casing are installation surfaces for heat-generating electrical and radio products. A shielding flat metal part of a l-shaped form is installed on the housing in the area of placement of electrical and radio products. The sheets of pyrolytic material contain areas in contact with the housing of the heat storage device. Sheet pyrolytic graphite materials have bends, which are formed according to the schemes shown in figure 4. The technical result is an increase in the efficiency of ERI protection against temporary external heat fluxes. 3 s.p. f-ly, 6 ill.

Description

The proposed utility model relates to thermal protection devices that use the latent heat of the phase transition of a heat-accumulating substance used to ensure the temperature regime of operation of heat-generating electric radio products (ERI) during cyclic operation and protection against short-term external thermal influences.

Thermal protection devices are widely used heat engineering means, and their development is actively continuing with the development of technology and materials used.

The known heat accumulator RU 2436020 (published 10.12.2011) in which the accumulation of thermal energy is carried out in cassettes filled with a metal heat-conducting structure and heat-accumulating substance. It is also known heat storage device presented in patent RU 2306494 (published on September 20, 2007), used for thermal stabilization of electronic equipment due to the form-stable substance in contact with the environment.

Various thermal protection devices for electronic modules in emergency conditions are also known. For example, RU 2324258 (published May 10, 2008), which is a metal case with layers of thermal insulation and heat-accumulating substance located inside it.

The prototype of the proposed utility model is the thermal protection device of the memory module RU 2473982 (published on 01/27/2013) containing a housing with a cover made of metal, while the inner surfaces of the housing form a cavity for placement in its center of an electronic memory module with a connecting cable, passive heat-insulating a gasket adjacent to the inner surface of the housing and made in the form of a glass with a lid, an active heat-shielding shell made of a composite mixture in the form of a detachable part, characterized in that the active heat-shielding shell consists of a housing with an internal electronic memory module and a cover interconnected by surfaces having the shape of a truncated cone, while the housing and the cover of the active heat-shielding shell are enclosed in sealed packages made of polyethylene to protect the inner surface and made of aluminum foil-coated polyethylene to protect the outer surface of the active heat shield.

The presented device is a closed case mounted on a printed circuit board. In the internal volume 3 cavities are formed - one serves to accommodate the protected microcircuit, the second is filled with a heat-accumulating substance, and the third is a heat-insulating substance. A protected electronic component is placed in the internal space, and the external cavities are filled with heat-insulating materials, while part of the thermal insulation material is ablative and is destroyed by external influences.

The disadvantages of the prototype include:

the presented device of thermal protection does not allow the operation of fuel electronic components due to the subsequent own overheating of the system;

the multilayer system in the case of semiconductor radio and electronic products (transistors, diodes, etc.) is redundant, because the external influence will lead to the destruction of the printed circuit board before the failure of the ERI;

low efficiency of heat removal from the internal volume of the device.

To eliminate the disadvantages presented, the described utility model is proposed. The main technical solutions to eliminate the disadvantages of the prototype are as follows:

in the design of the device, a single cavity is formed, filled with a heat-accumulating substance (hereinafter referred to as TAB);

in volume with heat-accumulating substance heat-conducting pyrolytic sheet materials are placed;

the casing is made of heat-conducting material and thermostatic ERI is placed on the outside of the casing;

the installation area is additionally protected by an external part with a possible direct impact, shielding the EIS.

The technical result is the protection of ERI from temporary external heat fluxes.

The technical result is achieved by the fact that the thermal protection device for heat-generating electrical and radio products contains a housing with a cover made of metal, while the inner surfaces of the housing form a cavity, the internal volume of the cavity being filled with phase-transfer heat-accumulating substance and sheet pyrolytic graphite material. In turn, the casing is equipped with at least one hole for mounting on a printed circuit board, and the side walls or the base of the casing are installation surfaces for heat-generating electrical and radio products. A shielding flat metal part of a l-shaped form is installed on the housing in the area of placement of electrical and radio products. The sheets of pyrolytic material contain areas in contact with the housing of the heat storage device. Sheet pyrolytic graphite materials have bends, which are formed according to the schemes shown in figure 4.

The implementation of the proposed device is illustrated by drawings.

1 and FIG. 2 presents the structure of UTZ in the context of:

1 - cover of the UTZ case;

2 - cavities filled with a heat-accumulating substance with placed pyrolytic sheet graphite (PGS) materials;

3 - metal heat-conductive housing of the UZT;

4 - printed circuit board of electronic equipment;

5 - fuel protected by ERI.

Figure 3 presents the appearance of the UTZ.

In FIG. 4 shows the cross-sectional views of a sheet of PGS material and possible options for filling the volume of TAB. A - direct addition with sharp angles and possible damage to the PGS structure in the bending areas; B - addition of PGS by formation of the contact area for better heat transfer from the ERI to the TAB and compensation of longitudinal compression due to bends in the base; C - equivalent to B, with the difference that rounding is carried out instead of sharp corners; G - perpendicular folding of the PGS with the formation of contact pads; D and E - similar to D, except for changing the geometry of the angles in the bending area or applying fillet material PGS, G - periodic bends are added to the geometry to increase the filling of the internal volume of the surfactant.

In FIG. 5. The dynamics of temperature is presented according to the results of mathematical modeling of a closed volume UTZ with and without PGS-based structure. Modeling was carried out with a heat source of a thermal power source of 1 W and a volume of TAV 1 cm3. The simulation result demonstrated a large area of the melting front of TAB with similar indicators of stored thermal energy.

Figure 6 presents a view of the UTZ with placed screening flat metal part of the l-shaped.

The principle of operation and some of the proposed features of the manufacture of the proposed utility model UTZ.

The cooled heat-generating ERI 5 is placed on the heat-conducting body 3 by means of fixing holes (not shown in Fig.).

In the hollow volume 2 of the housing 3 is placed TAB, made in the form of a folded structure of a pyrolytic sheet material (according to one of the addition forms presented in Figure 4). The geometric parameters of the TAB area are selected in such a way as to ensure an interference fit. The creation of compensating cavities is not required due to the sequential manufacture of the area with the surfactant and the corresponding hysteresis of the volume of the heat-accumulating substance.

For substances with a decrease in density in the solid phase (the volume of the solid is greater than the volume of the liquid): Fill the structure with liquid TAB, fill the internal volume, cool, remove excess material in the solid phase.

For substances with a decrease in density in the solid phase (the volume of the solid is less than the volume of the liquid): Filling the structure with liquid TAB, filling the internal volume, cooling.

In both cases, a cavity is formed without a surfactant, the volume of which depends on a change in the density of the substance during the phase transition. The type of TAB is selected based on the required temperature of the phase transition, chemical activity and compatibility with the materials of the housing. An example of a used TAB is water (as a substance with maximum heat capacity), paraffins, composition RU2190656, etc.

The prepared PGS structure with TAB is installed in the housing (or filled in the installed state), and then the internal volume is sealed with external elements of the housing.

TAB execution option: instead of pyrolytic graphite materials in the format of folded sheets, a porous open-cell structure is used.

In the case of the presence of direct external thermal influences that will affect the performance of the protected ERI, a shielding flat metal part of a l-shaped shape is installed on the UTZ in the area of the ERI location.

The proposed thermal protection device (UTZ) provides a temperature regime for the operation of radio products in the printed units of electronic equipment. To maintain the temperature regime of operation, they use their own heat capacity of structural materials and the latent heat of the phase transition of the heat-accumulating substance (TAB).

The overall dimensions and shape of the UTZ are determined by the design of thermostatically controlled ERI, the duration of their operating mode and the intensity of the expected external thermal effects. Upon reaching the TAV of its own melting temperature, a phase transition occurs, which significantly increases the potential heat capacity of the UTZ. The folded structure made of sheet pyrolytic carbon material (PGS) located in the bulk of the surfactant allows one to increase the thermal conductivity of the system and provide thermal contact between the liquid phase of the surfactant and the UTZ body due to capillary forces and direct physical contact.

Upon completion of the operation stages and termination of external thermal influences, the cooling of the electronic equipment occurs due to heat exchange with the environment. The time required to restore the initial parameters of the system is directly determined by the intensity of heat exchange with the environment and thermophysical parameters of thermal protection.

Claims (4)

1. A thermal protection device for heat-generating electrical and radio products, comprising a housing with a cover made of metal, the inner surfaces of the housing forming a cavity, characterized in that the internal volume of the cavity is filled with phase-transfer heat-accumulating material and sheet pyrolytic graphite material, in turn, the housing is equipped with at least than one hole for mounting on a printed circuit board, and the side walls or the base of the case are installation surfaces for heat-generating electro-radio Eliya. 2. The thermal protection device according to claim 1, characterized in that a shielding flat metal part of a l-shaped form is installed on the housing in the area of placement of radio and electronic products. 3. The thermal protection device according to claim 1, characterized in that the sheets of pyrolytic material contain areas in contact with the housing of the heat storage device. 4. The thermal protection device according to claim 1, characterized in that the sheet pyrolytic graphite materials have bends, which are formed according to the schemes shown in figure 4.

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