RU2350048C2 - Device to melt snow and prevent frosting up in areas with extremely low temperatures - Google Patents

Abstract

FIELD: mechanics, heating.

SUBSTANCE: proposed device comprises the following components, i.e. multiple sheet heaters wherein electrically conducting material made up of graphite and black is dispersed and mixed with disperse medium of polyimide-based synthetic pitch, water-resistant insulating materials made up of polyimide-based pitch. Each of the aforesaid materials features high heat stability, mechanical properties, electrical characteristics and chemical inactivity in a wide temperature range from very low to high temperatures. The device comprises also a container made from synthetic pitch to house sheet heaters and insulating layered materials. Note here that the sheet heaters are arranged in layers between which insulating material is fitted. The second version of the device comprises a set of sheet heater units.

EFFECT: simple design and long life, low production costs.

12 cl, 8 dwg

Description

FIELD OF THE INVENTION

The present invention relates to devices for melting snow and preventing freezing, designed for extremely cold regions, suitable for melting snow, heating or preventing freezing due to the use of sheet heaters in areas of extremely low temperatures, for example -40 ° C.

State of the art

As far as it was known, in order to ensure the function of melting snow, an exothermal wire placed in a sheath was embedded in the casing for the passage of current, the heat of which melted snow, while the exothermic wire placed in the sheath included: a conductive exothermic core made of a wire formed by a circular heating wire made from a metal, for example, a chromium-nickel alloy or a copper-nickel alloy; an insulating layer made of cross-linked polyethylene to cover the wire core; and a layer of sheath material made of vinyl chloride with a far infrared element included to cover the insulating layer.

However, with regard to the aforementioned known device with a conductive exothermic wire enclosed in a sheath disclosed in Japanese Application No. 2002-246158, since the conductive exothermic core is formed by a circular heating wire made of metal, for example, chromium-nickel or copper-nickel alloy, thermal efficiency is low, which necessitates an increase in radiated heat. Therefore, if the transmitted current is periodically required to be increased for a long time to obtain more heat, the wire core is damaged due to oxidation and carbonization, which leads to the fact that the heat source (i.e. the wire core) needs to be replaced after a short time , i.e. his service time is shortened. To replace the heat source, it is necessary to open the concrete or asphalt layer of the road surface, remove the debris from the extracted soil, then close up a new device with a conductive exothermic wire encased in the shell and re-bridge the section of the road, which requires a lot of labor and money. In fact, since the heat source is damaged over time due to the load from passing vehicles or freezing of the roadway, it often turns out that an inoperative heat source remains under the roadway.

However, the aforementioned known method using a circular metal heating wire is not suitable for melting snow on the road or preventing freezing of the road by stably supplying the necessary amount of heat for a long time, because when using the known method, the wire wrapped in a sheath is embedded into the road surface in areas of extremely low temperatures, for example, with an external temperature of -40 ° C, thermal efficiency is low, regardless of the supplied the excess current, and the dissipation and heat loss due to snow, ice and cold air become significantly larger.

Disclosure of invention

The objective of the present invention is to solve the above problems and to provide a device for melting snow and preventing freezing of the road surface, suitable for use by sealing the road surface in areas of extremely low temperatures, for example, with an external temperature of -40 ° C, which has high thermal efficiency and is suitable for melting snow on the road surface and preventing freezing of the road surface due to the stable supply of the right amount of heat for a long belt while having a small size, a simple structure and long service life with low production costs.

To solve the above problem, the present invention provides a device for melting snow and preventing freezing, intended for areas of extremely low temperatures, which contains:

a variety of sheet heaters, in each of which an electrically conductive material consisting of graphite and soot is dispersed and mixed with a dispersed medium of synthetic resin;

moisture resistant electrical insulation materials consisting of polyimide-based resins having high heat resistance, mechanical characteristics, electrical characteristics and chemical inertness over a wide temperature range from very low to high temperatures; and

synthetic resin container for holding sheet heaters and electrical insulating materials in the form of layers,

while the sheet materials are placed in layers, with electrical insulation material between them.

The present invention also provides a device for melting snow and preventing freezing, designed for areas of extremely low temperatures, the device includes many blocks of sheet heating, and each block of sheet heaters includes:

a variety of sheet heaters, in each of which an electrically conductive material consisting of graphite and soot is dispersed and mixed with a dispersed medium of synthetic resin;

moisture resistant electrical insulation materials consisting of polyimide-based resins having high heat resistance, mechanical characteristics, electrical characteristics, chemical inertness over a wide temperature range from very low temperatures to high temperatures; and

synthetic resin container for holding sheet heaters and electrical insulating materials in the form of layers,

while sheet heaters are placed in layers, with electrical insulation material between them,

moreover, many blocks of sheet heaters are embedded in the body of asphalt or concrete, while blocks of sheet heaters are placed in the body next to each other in the desired order with the desired number of steps and at the desired depth.

Preferably, sheet heaters and electrical insulating materials are arranged concentrically, with a cylindrical cross section, in a cylindrical container of synthetic resin.

Preferably, in a heat heater, the weight ratio of graphite, carbon black and dispersed medium of synthetic resin is 2-5: 1-3: 7-9, respectively, and even more preferably, the weight ratio of 4: 2: 8, respectively.

Preferably, the synthetic resin dispersed medium is a fluorine-based resin or a polyethylene resin.

Preferably, the insulating material is made of a polymer of pyromelitic dianhydride and 4,4-diaminodiphenyl ether.

Preferably, the synthetic resin container is made of polyethylene resin.

The present invention provides a device for melting snow and preventing freezing of the road surface, suitable for use by sealing it on the road surface in areas of extremely low temperatures, for example, with a temperature of -40 ° C, having high thermal efficiency and capable of melting snow and preventing freezing of the road surfaces due to the stable release of the required amount of heat for a long time and having a simple design and low production costs Ata.

Brief Description of the Drawings

Figure 1 is a cross section of a block of sheet heaters in accordance with a preferred embodiment of a device for melting snow and preventing freezing, intended for areas of extremely low temperatures, in accordance with the present invention;

Figure 2 is a plan view of a block of sheet heaters;

Figure 3 is a longitudinal section of a block of sheet heaters;

Fig. 4 is a cross-sectional view of a body with sheet heater blocks embedded therein in accordance with a preferred embodiment of the invention;

Fig. 5 is a graph illustrating temperature characteristics when measuring temperature in a body, on a body surface, and on side surfaces of a body in a room when several blocks of sheet heaters are embedded in this body in accordance with a preferred embodiment of the invention;

6 is a graph of temperature characteristics when measuring temperature in the body, on the surface of the body and on the side surfaces of the body in a cold bath when several blocks of sheet heaters are embedded in this body in accordance with a preferred embodiment of the invention;

7 is a graph illustrating characteristics obtained by measuring voltage, electric power, integrated electric power and current when several blocks of sheet heaters of blocks are embedded in the body;

Fig. 8 is a graph illustrating thermal characteristics when measuring alternating voltage and electric power of one block of sheet heaters in accordance with a preferred embodiment in a cold bath.

The implementation of the invention

Next, preferred embodiments of the invention will be described with reference to the accompanying drawings.

Block 1 sheet heaters includes: many sheet heaters 3; waterproof electrical insulation material 2; and a container 4 made of synthetic resin for receiving sheet heaters 3 and electrical insulation material 2 in the form of layers, while sheet heaters 3 are placed in layers, and insulation material is placed between the layers of sheet heaters. The total length of the synthetic resin container 4 may be, for example, about 500 mm.

The insulating material 2 consists of a polyimide-based resin, which has high heat resistance, mechanical characteristics, electrical characteristics, chemical and radiation resistance in a wide temperature range, for example, from -269 ° C to high temperatures, for example, 400 ° C. The insulating material 2 may be, for example, a polymer of pyromellitic dianhydride and 4,4-diaminodiphenyl ether.

In a sheet heater 3, an electrically conductive material consisting of graphite and soot is dispersed and mixed with a dispersed medium of synthetic resin. The sheet heater 3 contains graphite, carbon black and a dispersed medium of synthetic resin in a weight ratio of 2-5: 1-3: 7-9, respectively, and more preferably in a weight ratio of 4: 2: 8, respectively. After mixing, for example, the mixture is extruded to form a sheet heater 3, so as to obtain a cylindrical cross-section. In addition to the electrically conductive material consisting of graphite and soot, as substances added to a dispersed medium of synthetic resin, for example, ashes from industrial wastes, metal oxides such as molybdenum dioxide, aluminum titanate and lead oxide, carbide, for example carbide can be introduced silicon and calcium carbide, to obtain radiation in the far infrared region of the spectrum so that activation, by propagating electromagnetic waves of far infrared radiation, occurs in resonance with vibrations of molecules ha and ice, without loss of thermal energy generated by the sheet heater 3, and thus snow can melt and prevents freezing due to the thermal energy released when returning the ice molecules from the excited to the ground state.

As a dispersion medium of a synthetic resin, a fluorine-based resin can be used. Fluorine-based resin has good characteristics, for example, resistance to low temperatures, heat resistance, chemical inertness, wear resistance, impact resistance, stable electrical characteristics and good adhesion to electrical insulation material 2. If the weight ratio of graphite, carbon black and dispersed medium of synthetic resin is maintained, as indicated above, strong adhesion of the dispersed carbon black to the dispersed medium of synthetic resin is obtained, and the carbon black is evenly distributed in the dispersed synthetic medium resin, thereby reducing electrical resistance. A synthetic resin dispersion medium can be obtained from a polyethylene resin.

The sheet heater 3 and the electrical insulating material 2 are placed centrically and have a cylindrical cross section. As can be seen in FIG. 1, a plurality of sheet heaters 3 and electrical insulating materials 2 are arranged in layers (three layers of sheet heaters 3 and electrical insulating materials 2 respectively are shown in FIG. 1 as an example) and are placed in a rigid cylinder-shaped synthetic resin container 4 . Although FIG. 1 shows as an example three laminated layers, the number of laminated layers may be any and the thickness of the layers may vary depending on the need. For this reason, the sheet heater 3 and the electrically conductive material 2 are given a concentric shape with a cylindrical cross section so that, along with the compactness of one sheet heater 3, a large heat-emitting region is obtained, and the combination of these regions in the laminated sheet heater 3 can be so large that stably provide the necessary amount of heat for a long time.

In a preferred embodiment, the synthetic resin container 4 is made of polyethylene resin and has a cylindrical shape. However, the material for the synthetic resin container 4 is not limited only to polyethylene resin. It can be a polyacrylic resin, polymethacrylate resin or polypropylene resin.

2 and 3, 5 and 5 ′ indicate electrodes mounted on the front or rear end of the synthetic resin container 4. Each electrode 5, 5 'is made, for example, of copper foil. However, the material is not limited only to copper foil and may be different provided that it has good electrical conductivity, is suitable for machining, and is easily accessible. Positions 6 and 6 'marked conductive parts connected to the electrodes 5 and 5'.

In Fig. 4, reference numeral 7 denotes a body of concrete or asphalt, into which blocks 1 of sheet heaters are embedded. In this case, several blocks 1 of sheet heaters are sealed to a depth of H, located next to each other in the desired order and forming the desired number of steps.

In a preferred embodiment of the invention, when the sheet heater blocks 1 are embedded under the surface of the road to melt the snow layer on the road in low temperature areas or to prevent freezing of the road, the following experiment was carried out to confirm the effect obtained under laboratory conditions. As shown in Fig. 4, heat-insulating material 9 with a thickness of 25 mm was laid on a concrete base with a thickness of 70 mm, then two blocks 1 of sheet heaters 1 were placed next to each other, on both sides of these two blocks 1 of sheet heaters a heat-insulating material 10 of thickness 12.5 mm, and all this was poured with concrete as a material for paving so that the depth H from the base to the road surface was about 50 mm, thus, two adjacent blocks of 1 sheet heaters were sealed next to each other corner in the body 7 of concrete to a depth of H about 50 mm from the road surface.

In the above example, the depth H was about 50 mm, however, the depth H can be selected by anyone depending on the need.

For the above-mentioned body 7, concrete with shrinkage of 8-12 was used during laying.

Then, to confirm the effectiveness of the blocks 1 of sheet heaters under laboratory conditions, a metal pipe 11 was inserted into the concrete body 7 with a temperature sensor S installed in it, with which the temperature in the body 7 was measured. For example, glass wool, polyurethane foam can be used as thermal insulation material or asbestos.

The body 7, in which blocks 1 of sheet heaters were embedded, can be not only concrete. For example, asphalt may be used as the material for the body 7. When using asphalt, the sheet heater block 1 can also prevent the thermal destruction of the sheet heaters by using an insulating material 2 made of polyamide resistant to high temperatures, for example 400 ° C.

A preferred embodiment of a device for melting snow and preventing freezing, for use in areas with extremely low temperatures in accordance with the present invention has the structure as described above. In the apparatus, a plurality of sheet heaters 3, consisting of graphite, carbon black and a dispersion medium of a fluorine-based synthetic resin, are arranged in layers, alternating with layers of a waterproof electrical insulating material 2, consisting of a polyimide-based resin, wherein the polyimide-based resin, such as a polymer pyromelitic dianhydride and 4,4-diaminodephenyl ether is particularly suitable since it has excellent heat resistance, mechanical characteristics, electrical characteristics, and resistance to chemical reagents and radiation in a wide temperature range from very low, for example -269 ° С, to high, for example 400 ° С. As shown in FIG. 1, three sheet heaters 3 are arranged concentrically in layers, with a cylindrical cross section, and are arranged in a cylindrical container 4 of synthetic resin, forming a block 1 of sheet heaters.

The surface temperature of the sheet heater block, made as described above, was measured over time at room temperature. The measurement results are shown in table 1.

Table 1 Surface temperature in ° C of a sheet heating block with three-layer lamination Time (in minutes) one 43 2 58 3 67 four 72 5 79 6 85 7 86 8 87 9 88 10 94 twenty 95 thirty 93 60 94 120 94

The conditions under which the measurements were made are as follows: room temperature 26 ° C, voltage 100 V, electric power 32 W and electric resistance of the sheet heater 3-313 Ohms. Under these conditions, the surface temperature of the synthetic resin container 4 with the sheet heater 3 placed in it was measured, depending on the transmission time of the electric current (namely, through the conduction time intervals) in 1, 2, 3, 4, 5, 6, 7, 8 , 9, 10, 20, 30, 60 and 120 minutes. The measured surface temperature is summarized in Table 1. The results shown in Table 1 show that after a time of 10 minutes the surface temperature of the sheet heater unit 1 (i.e., the surface temperature of the synthetic resin container 4) became almost constant and was between 93 and 95 ° C.

In the second case, two blocks 1 of sheet heaters made as described above were sealed next to each other in a concrete body 7 to a depth of H 50 mm from the road surface, in which, as shown in FIG. 4, on a concrete base 8 with a thickness of 70 Heat insulation material 9 was laid with a thickness of 25 mm, after which two blocks 1 of sheet heaters were placed next to each other. Then, electric current was passed through two blocks 1 of sheet heaters in accordance with the experiment at an alternating voltage of 100 V, power of 30 W, and room temperature A of about 25 ° C; then, temperature B was measured in body 7, surface temperature C of body 7, and side temperature D body surface 7 depending on time. The results are shown in FIG.

As can be seen from Figure 5, after 4 hours (240 minutes), the temperature B of the body 7 was about 88 ° C, the surface temperature C of the body 7 was about 78 ° C and the temperature D of the side of the body 7 was about 53 ° C, i.e. temperatures were significantly high.

In the third case, two leaf heater blocks 1 were made in the same way as described above (as shown in FIG. 4), then electric current was supplied to two leaf heater blocks 1 (i.e., leaf heaters 3) in accordance with the experiment at an alternating voltage of 100 V and an electric power of 30 W at a temperature A 'in a cold bath of about -40 ° C, and the temperature B' was measured in the body 7, the surface temperature C of the body 7 and the temperature D 'of the side surface of the body 7 as a function of time. The results are shown in Fig.6.

As can be seen from FIG. 6, after two hours (120 minutes), the temperature B 'in the body 7 reached and then remained at about 40 ° C, the surface temperature C' of the body 7 reached and remained at about 10 ° C, and the temperature D 'of the side surface of the body 7 reached and remained around - 25 ° C. Thus, all temperatures were significantly high.

Therefore, in accordance with the results described above, it was found that when sheet heater units 1 are used in accordance with a preferred embodiment of the invention for melting the snow covering the road, or for preventing freezing of the road in extremely low temperature regions where the outdoor temperature drops to - 40 ° C, embedded in a concrete body 7 under the road surface, as described above, and electric current is passed through them, these blocks of sheet heaters can melt snow, cover driving the road, or prevent freezing of the road.

In the fourth case, voltage (V), electric power (W) and integrated electric power (W; watt-hour) were measured as a function of time under conditions when the resistance value of the sheet heater block was 332 Ohms. The results are shown in Fig.7.

As can be seen from Fig. 7, when applying an AC voltage of 100 V and a power of 80 A to sheet heaters 1 after two hours (120 minutes), the consumed electric power was 30 W, and the integral electric power was about 0.2 W-hour, from which shows that low electrical power is consumed, and energy efficiency is high.

In the fifth case, the surface temperature of one block 1 of sheet heaters, measured as described above, in a cold bath at an alternating voltage of 100 V, electric power of 30 W, and a resistance of 310 Ohms, was measured as a function of time. The results are shown in Fig. 8.

In accordance with these results, after 5400 seconds and at a temperature A "in a cold bath of -36 ° C, the surface temperature C" of body 7 reached and remained from -16 to -17 ° C.

Therefore, when comparing the case when one block 1 of sheet heaters was embedded in body 7, with the case when many adjacent sheet metal blocks 1 were embedded in body 7, it was found that it is possible to stably provide the necessary heating for a long period of time so that snow lying on the road could be melted, and freezing of the road surface could be prevented.

Since many blocks 1 of sheet heaters, sealed next to each other in the body 7, are closed from below and on both left and right sides by heat-insulating materials 9, 10, these materials protect the blocks 1 of sheet heaters from the cold coming from outside the body 7, for example, from snow , ice or external air, and the heat radiated by the blocks 1 of sheet heaters is transferred to the environment of the body 7 without loss.

The number of blocks 1 of sheet heaters, the method of their placement and the depth of embedding in the body 7 are not limited to the examples described above and can be freely selected depending on the needs.

Since in each sheet heater 3 of the block 1 of sheet heaters, the electrically conductive material of graphite and soot is dispersed in a dispersion medium of a synthetic resin based on fluorine, graphite and soot are distributed evenly, so that the electrical resistance can be reduced, thereby ensuring a stable electrical characteristic. The adhesion of the sheet heater 3 and the insulating material 2 becomes high. Therefore, the sheet heater 3 according to the present invention has good thermal efficiency and can stably provide the desired amount of heat for a long time. Moreover, the possibility of damage to the sheet heater 3 due to oxidation or carbonization is reduced, and the destruction of the cable becomes hardly possible. Therefore, the heat source does not require replacement for a long time, from which it follows that the snow on the road will melt and its freezing will also be prevented for a long time.

Since the sheet heaters 3 according to the present invention are placed in a synthetic resin container 4 in layers, as described in detail above, they are well protected by this container 4, i.e. a load such as the weight of vehicles on top or pressure on the right and left can be reduced. Moreover, the layers of cylindrical sheet heaters 3 are arranged concentrically in cross section, each sheet heater 3 evenly radiates heat in the radial direction from the center to the periphery, which provides a large amount of heat.

Further, since sheet heaters 3, each of which has a cylindrical shape, are arranged concentrically and in layers with electrical insulation material 2 inside the container 4, for each sheet heater 3, the region radiating heat can be wide, despite its compact size, as a result of which melting is ensured snow covering the road and prevents frosting of the road for a long time.

The magnitude of the electrical resistance of each of the many sheet heaters 3 can be selected different to obtain a larger amount of total radiated heat, if necessary.

In the example described above, the device in accordance with the present invention is used in areas of extremely low temperatures on the roads by sealing it under the surface of the roads. However, the devices of the present invention can be used on highways, parking lots, stairs, driveways, road bumps, airfields, railways, in garages to prevent freezing of any particular place.

The device according to the present invention is suitable for embedding in concrete or asphalt in areas of extremely low temperatures. The sheet heater block according to the present invention has excellent thermal efficiency and, despite its compact size, can stably produce the required amount of heat for a long time, thereby melting the snow covering the road and preventing it from freezing for a long time without frequent replacement of the sheet heater block .

The above preferred embodiments of the invention are described in order to help understand its essence, and any specialist can make variations of the invention within the claimed scope.

Claims (12)

1. Device for melting snow and preventing freezing, intended for use in areas of extremely low temperatures, containing
many sheet heaters, in each of which an electrically conductive material consisting of graphite and soot is dispersed and mixed with a dispersed medium of synthetic resin; moisture resistant electrical insulation materials consisting of polyimide-based resins having high heat resistance, mechanical characteristics, electrical characteristics and chemical inertness over a wide temperature range from very low to high temperatures; and
synthetic resin container for holding sheet heaters and electrical insulating materials in the form of layers,
while the sheet materials are placed in layers, with electrical insulation material between them. 2. The device according to claim 1, characterized in that a plurality of sheet heaters and insulating materials are arranged concentrically with a cylindrical section in a cylindrical container of synthetic resin. 3. The device according to claim 1, characterized in that the sheet heaters contain graphite, soot and a dispersed medium of synthetic resin in a weight ratio of 2-5: 1-3: 7-9, respectively, and preferably in a weight ratio of 4: 2: 8 respectively. 4. The device according to claim 1, characterized in that the dispersion medium of a synthetic resin is a fluorine-based resin or a polyethylene resin. 5. The device according to claim 1, characterized in that the insulating materials are made of a polymer of pyromelitic dianhydride and 4,4-diaminodiphenyl ether. 6. The device according to claim 1, characterized in that the container of synthetic resin is made of polyethylene resin. 7. A device for melting snow and preventing freezing, designed for areas of extremely low temperatures, including many blocks of sheet heaters, each block of sheet heaters contains:
many sheet heaters, in each of which an electrically conductive material consisting of graphite and soot is dispersed and mixed with a dispersed medium of synthetic resin;
moisture resistant electrical insulation materials consisting of polyimide-based resins having high heat resistance, mechanical characteristics, electrical characteristics, chemical inertness over a wide temperature range from very low temperatures to high temperatures; and
synthetic resin container for holding sheet heaters and electrical insulating materials in the form of layers,
while sheet heaters are placed in layers, with electrical insulation material between them,
moreover, many blocks of sheet heating blocks are embedded in the body of asphalt or concrete, while blocks of sheet heaters are placed in the body next to each other in the desired order with the desired number of steps and at the desired depth. 8. The device according to claim 7, characterized in that a plurality of sheet heaters and insulating materials are arranged concentrically with a cylindrical section in a cylindrical container of synthetic resin. 9. The device according to claim 7, characterized in that the sheet heaters contain graphite, carbon black and a dispersed medium of synthetic resin in a weight ratio of 2-5: 1-3: 7-9, respectively, and preferably in a weight ratio of 4: 2: 8 respectively. 10. The device according to claim 7, characterized in that the dispersion medium of a synthetic resin is a fluorine-based resin or a polyethylene resin. 11. The device according to claim 7, characterized in that the insulating materials are made of a polymer of pyromelitic dianhydride and 4,4-diaminodiphenyl ether. 12. The device according to claim 7, characterized in that the container of synthetic resin is made of polyethylene resin.

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