RU2620984C1 - Housing of protective board information storage - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relevant to means for protection of board storages of flight information (SFI) of such aircraft as airplanes and helicopters against exposure to such external destroying factors as: mechanical shocks, overloads, vibration, stationary pressures, as well as factors of fire and corrosive liquids. Housing of the protective board information storage is intended for protection against exposure to such external destroying factors as: mechanical shocks, overloads, vibration, stationary pressures, as well as factors of fire and corrosive liquids and consisting of external housing made of high-temperature alloy, which is provided with perforated drainage holes and on the outside coated with layer of heat-insulation bimorph heat-shielding inter-layer; and of internal shockproof container made of high-temperature corrosion-proof alloy, which from above is coated with layer of dry elastic porous-fibrous material of low thermal conductivity, which functions as thermal insulation and coated from above with metal foil, wherein that inner surface of external housing is coated with thermoplastic polymer film, internal airtight container is vacuumed, and protected object is held in the center of container with the aid of four and more conical springs, which tops are directed to container housing. Ice layer is placed between internal container and external housing of container. Intermediate mesh housing provided with porous steam-proof fabric that is covered with nap, for example, fur, is placed there. Position of external housing, intermediate mesh housing and internal container relative to each other is fixed with the aid of inserts made of dry porous elastic heat-insulating and incombustible material coated with water-proof heat-resistant film.

EFFECT: device for protection of aircraft board SFI against exposure to external destroying mechanical factors, which provides protection of 100 % against corrosive liquids and at least 2-fold increase of time of exposure to high temperatures.

5 cl, 3 dwg

Description

The invention relates to protection means for on-board flight information storage devices (NPI) of aircraft (aircraft) - aircraft and helicopters from the effects of external destructive factors: mechanical shocks, overloads, vibration, static pressures, as well as fire factors and corrosive liquids. The device can also be used to protect valuable information and materials on spacecraft descent vehicles, in automobile, railway and sea transport.

The device consists of an internal airtight container in which a vacuum is created, and the protected object is held in the center of the container by four or more conical springs; an outer casing of heat-resistant alloy perforated by drainage holes, externally coated with a layer of heat-insulating bimorph heat-shielding coating (known composite material), and with an inner thermoplastic polymer film. Between the inner container and the outer case of the container there is an ice layer, in which there is an intermediate mesh body with a porous fabric with a pile attached, such as fur, as well as a layer of elastic porous-fibrous material, hermetically separated from the ice layer by a metal foil with an external reflective surface.

The device provides NPI protection in accordance with the requirements of clause 6.2.11 of OST 1 01080-95 and international TSO requirements ("Technical Standart Order", TSO-C124a, Washington, DC; 8/1/96) for on-board protected flight information storage devices .

A device for protecting microelectronic equipment is known (patent RU 2042294, published on 06/20/1995), made in the form of a sealed container with circuit boards located in it with cooled semiconductors, into which a dielectric fluid is heated, heated to boiling, the vapor of which is cooled by a condenser, located at the top of the container, condense on the walls of the container and, flowing down on them, cool the semiconductors.

The disadvantage of this device is that it can only work in stationary conditions together with systems for supplying a dielectric fluid, its heating and cooling, which excludes its autonomous operation in case of accidents in transport.

A device is known for providing the thermal regime of cryogenic capacity during operation of a space object (patent RU 2413661, published March 10, 2011), which contains a sealed screen-vacuum thermal insulation of soft non-metallic material. Vacuum in the shell is formed by communicating the cavity with outer space through a system of valves.

The disadvantage of this device is the lack of a rigid body, which makes it inapplicable to atmospheric pressure.

Closest to the claimed invention is a family of devices for protecting objects from external destructive factors: mechanical shocks, overloads, vibration, static pressures, as well as fire factors (patents: RU 2269168, published January 27, 2006; RU 2269169, published January 27, 2006; RU 2269170, published January 27, 2006; RU 2273895, published April 10, 2006; RU 2281230, published August 10, 2006), consisting of protective layers sequentially located in the depths: outer, intermediate, and inner, as well as a bimorph heat-protective coating on the outer surface of a layer. The outer shock-resistant layer is perforated through the drainage holes, the diameter of each of which does not exceed half the thickness of the outer shock-resistant layer, through which water vapor is throttled during the thermal decomposition of crystalline hydrates, of which the inner layer consists, previously passing through the intermediate layer, intended for passive heat protection of the stored object acting as a heat insulator due to the low thermal conductivity of the refractory dry porous material. To increase the efficiency of thermal protection, the inner layer on both sides is covered with metal heat-reflecting gaskets.

The disadvantages of this family of devices are:

- a large mass of the outer shock-resistant layer, since it has the largest dimensions and perceives all mechanical stresses on itself;

- water vapor passing through the intermediate layer fills the pores of the porous-fibrous material of the layer and thereby increases its thermal conductivity;

- the protected object tolerates large overloads, since with a strong outer casing, the deformation of which is insignificant, the stopping distance is only the sum of the deformations of the device casing and the surface with which the device collides.

The claimed device solves the problem of protecting the NPI in accordance with the requirements of clause 6.2.11 of OST 1 01080-95 and the international requirements of TSO ("Technical Standart Order", TSO-C124a, Washington, DC; 8/1/96) for on-board protected NPI .

The implementation of the task is achieved by the following technical solutions:

1. The protected object - NPI - in a rigid case 1 (Fig. 1) by four or more conical springs 3 is held in the center of the shockproof sealed container case 2 made of a heat-resistant corrosion-resistant alloy, consisting of two halves interconnected. In the shockproof sealed housing 2 of the container is mounted a sealed connector 4 of fireproof dielectric strong material, to which the cable is sealed, and a fitting with a check valve 5 for pumping air. The vacuum level is set according to the tolerance limit for NPI. The casing of the NPI 1 has a reflective coating on top. The outer surface of the shockproof sealed container body is polished and coated with a thin layer of metal, such as silver, to form a mirror surface, its inner surface is rough black in order to absorb thermal radiation reflected from the housing 1, and significantly reduces the contact area of the conical spring with the housing. Conical springs are made with different frequencies of natural vibrations and their peaks rest against the housing 2. On top of the container body 2 is covered with a layer of dry elastic porous-fibrous material 6 (Fig. 1 and 3) of low thermal conductivity, which performs the function of thermal insulation, which is sealed from above with a metal foil 7 for example, aluminum foil.

2. The outer casing 8 consists of two halves (Fig. 1 and 2), is made of heat-resistant steel, perforated through the drainage holes with the distribution of one or more holes per square centimeter, the outside is covered with a layer of heat-insulating bimorph heat-resistant coating 9 (known composite material), and with an internal thermoplastic polymer film 10, which ensures the tightness of the outer casing 8 during normal operation.

3. Between the buildings 2 and 8, a mesh 11 is installed, consisting of two halves (Fig. 1 and 2), to which a fur 12 is attached on a porous vapor-permeable base with hollow porous hairs, impregnated with an anti-pyrolysis composition. The position of the grid 11 in the device is fixed using inserts 13 and 14 of a dry porous elastic heat-insulating non-combustible material coated with a waterproof heat-resistant film. The space between buildings 2 and 8, which is filled with water containing a combustion inhibitor, mesh 11 divides into two cavities a and b. The fur, located in cavity 6, significantly strengthens the ice with its hairs when water freezes. The pores of the fur base serve as chokes, creating resistance to the movement of steam, which ultimately increases heat removal.

The device is illustrated by the following drawings:

- in FIG. 1 fragment of the section of the device in the diametrical plane;

- in FIG. 2 - a cutaway section of the device in zone A (section of the outer casing and mesh with fur);

- in FIG. 3 - a cutaway section of the device in zone B (section of the container body with thermal insulation).

The device operates as follows.

Ice is frozen using an on-board freezer and / or outside air having a negative temperature. A layer of dry elastic porous-fibrous material 6 and inserts 13 and 14 compensate for thermal expansion during freezing of ice.

A) The NPI is protected by a sealed container body made of a heat-resistant corrosion-resistant alloy.

B) The container body is designed to withstand pressure corresponding to a depth of at least 6,000 m.

B) The reduction of the overload acting on the protected object (NPI) is due to the partial plastic deformation of the outer casing, cracking of ice and depreciation of the conical springs holding the protected object in the container. Different values of the natural vibration frequency of the springs give an additional effect of energy dissipation.

D) The danger of piercing is reduced by the multilayer design of the device. The presence of ice and the nature of its destruction causes an internal rebound effect, which significantly reduces the likelihood of an impact perpendicular to the surface of the inner container body.

E) When fire factors act on the outer heat-resistant casing, the layer of bimorph heat-protective coating applied to it foams at a temperature of no more than 260 ° C with a multiple increase in volume, thereby significantly reducing the transfer of heat from the external environment to the device.

Further heating of the device in cavity a leads sequentially to heating the ice, its melting, bringing the water to a boil. At the same time, the thermoplastic film is heated, which, when the temperature reaches 110-115 ° C under steam pressure, breaks through at the locations of the drainage holes of the outer casing, forms an acute diaphragm at the inlet of each drainage hole, which has a large resistance coefficient and prevents the free flow of steam, which also increases the heat capacity last one. Through the drainage holes, the vapor containing the combustion inhibitor extends beyond the heat-resistant outer casing. There is a fire extinguishing effect in close proximity to the device and, as a result, a decrease in the heat flux power acting on the bimorph heat-shielding coating, and after its destruction on the heat-resistant casing.

After the evaporation of water from cavity a , the process of evaporation of water from cavity b occurs. in this case, the steam passes through two stages of throttling: through the fur base and throttle openings of the outer casing.

The effectiveness of the use of the inventive protective housing NPI is determined by the following circumstances. The presence of an ice shell between buildings 2 and 8, formed by freezing the water there, either in a ground-based refrigeration unit, or when cooling with low-temperature air flows during the flight of an aircraft in the upper atmosphere or when it is on the ground in winter conditions, allows:

1. To increase the impact resistance of NPI due to the effect of "nutshell". Upon impact on the ground, on another object in the air or upon the action of a shock wave and fragments, part of the kinetic energy will be absorbed by the work of destroying (cracking) the ice shell.

2. To increase the heat resistance of NPI, because, unlike the known devices with water in the liquid phase or in crystalline hydrates, part of the thermal energy will be spent on heating the ice shell to the melting temperature (0 ° C under normal conditions) and the actual melting of ice at this temperature . This effect "E" can be estimated from the ratio:

where E ₁ and E ₂ - heat absorption of the claimed housing NPI and the body of the prototype.

The values of E ₁ and E ₂ can be determined from the expressions, respectively:

where m is the mass of water / ice, C _l = 2.11 kJ / kg is the heat capacity of ice, T ₀ is the initial temperature of the ice shell, T _t = 0 ° C is the ice melting temperature, r = 330 kJ / kg is the specific heat of melting ice, С _в = 4.19 kJ / kg / deg - average heat capacity of water, q = 2256 kJ / kg - specific heat of water evaporation.

For example, at T ₀ = -40 ° C (temperature at the flight altitude of the aircraft) and, having reduced m, from (1) we get:

E = (40 * 2.11 + 330 + 100 * 4.19 + 2256) / (100 * 4.19 + 2256) = 1.155 = 115.5%.

Thus, the ice shell, in addition to increased impact resistance, also provides an increase in the heat resistance of NPI by 15.5%.

The vacuum in the container 2 reduces thermal conductivity by more than 10 times and, accordingly, increases the time of protection of NPI at high temperatures.

Thus, the claimed device for protecting onboard NPI aircraft from the effects of external destructive factors using all the above essential features provides 100% protection against aggressive fluids, at least a 2-fold increase in the residence time at high temperatures under all other equal prototype conditions, as well as allows to expand the scope of application: in space landers, in automobile, railway and sea transport.

The spherical shape of the device is the most compact and protected, but the manufacturer can give it a different geometric shape corresponding to the installation location of the device.

Claims (5)

1. The case of a protected on-board storage device designed to protect against external destructive factors: mechanical shocks, overloads, vibration, static pressures, as well as fire factors and corrosive liquids, consisting of: an outer casing of a heat-resistant alloy perforated with drainage holes, coated outside a layer of heat-insulating bimorph heat-shielding coating, an intermediate layer, and an internal shock-resistant container made of heat-resistant corrosion-resistant alloy which is covered on top with a layer of dry elastic porous-fibrous material of low thermal conductivity, which performs the function of thermal insulation, which is covered with a metal foil on top, characterized in that the outer case is coated with a thermoplastic polymer film on the inner surface, a vacuum is created in the inner sealed container, and the protected object is held in the center of the container with four or more conical springs facing their tops to the container body, between the inner container and the outer case the container is an ice layer in which there is an intermediate mesh body with a porous vapor-permeable fabric attached to it with a pile, for example fur, the position of the outer housing, the intermediate mesh housing and the inner container relative to each other is fixed using inserts of dry porous elastic heat-insulating non-combustible material coated waterproof heat-resistant film. 2. The device according to p. 1, characterized in that the outer surface of the shockproof sealed enclosure of the inner container is polished and coated with a thin layer of metal, such as silver, to form a mirror surface, its inner surface is rough black. 3. The device according to claim 1, characterized in that the layer of elastic porous-fibrous material with which the casing of the inner container is externally covered is hermetically separated from the ice layer by a metal foil with an external reflective surface. 4. The device according to p. 1, characterized in that the ice contains a combustion inhibitor. 5. The device according to claim 1, characterized in that the thermoplastic polymer film is capable of breaking through at a temperature of 110-115 ° C under steam pressure and the formation of an acute diaphragm having a large resistance coefficient at the inlet of each drainage hole of the outer casing prevents the free flow of steam , which also helps to increase the heat capacity of the latter.

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