JPS585429B2 - Method and device for preventing icing and snow accretion on the sign surface of traffic signs - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method and apparatus for preventing icing and snow from accumulating on sign surfaces of railways, roads, etc., such as speed signs, caution signs, curved mirrors, and delineators for guardrails in snowy regions and cold regions. Regarding.

For some time now, the signs installed on railroads and roads in snowy and cold regions have become unclear due to ice and snow buildup on the sign surfaces, and railway, road and other operators have been forced to take measures to prevent this. I was in a state of confusion.

Accordingly, the present invention uses geothermal heat pipes to pump up geothermal heat to melt the ice and snow on the sign surfaces, that is, heats the sign surfaces using the geothermal heat pipe temperature.

Suitable heat pipes in this case are iron-ammonia, iron-alcohol, iron-freon, and iron-water-alcohol types, but iron-ammonia heat pipes are subject to the restrictions of Class 2 pressure vessels. Therefore, ribs are provided on the outer circumferential surface of the pipe to double as reinforcement and to increase the heat transfer (heat receiving) area, thereby assisting the input of geothermal heat.

The length of the pipe (earth heat pipe) inserted underground requires an Iom of 3 m or more, and depending on the conditions of the cold region, a frozen layer is formed about 0.7 m below the ground surface. In that case, the underground part of the earth heat pipe needs to be inserted for a long time, and the part exposed above the ground, the enlarged condensing surface part at the end of the condensing part, and the part at least 0.0
．． Each surface up to a depth of about 3 to 0.7 m is coated with a heat insulating material to prevent heat radiation.

This enlarged and condensed surface portion is positioned on the back side of the sign surface.

As a result, it is possible to easily pump up geothermal heat of about 200 W at a depth of 5 m underground, depending on the size of the sign surface, and it is now possible to prevent ice and snow from accreting on the sign surface. .

Regarding the amount of heat dissipated from the sign surface, the results shown in Table 1 below were obtained.

However, the earth heat pipe is 20A, iron pipe for pressure piping (outer diameter 27.2rr, inner diameter 21.4mm, thickness 2.9mm).
mm), and the underground length is 5 m, and the actual effective length is 4 m.
Ribs with a width of 5 mm and a thickness of 2 m are attached to the outer periphery at 4 locations with an effective total length of 4 m, and the exposed length on the ground is 1.5 m, the diameter of the sign surface is 0.3 m, and the thickness and width of the hollow metal box container is 0.04 m. It is.

Snow that adheres due to snowfall will easily melt if the temperature of the marker is 3C or higher, but as shown in Figure 4, in the northern part of the Japanese archipelago, the ground temperature is about 10C below 3m underground.

Burying the heat pipe deeper means that the ground temperature is higher, which increases the temperature of the heat pipe and the temperature of the sign, but at the same time, heat is dissipated due to the weather conditions in the outside world, so it is difficult to overcome this. The temperature of the sign must be maintained.

In the table, convective heat loss is due to wind, radiant heat loss is the temperature difference between the sign and the outside air, evaporative heat loss is from frozen snow, ice melting heat loss is from frozen snow, and flowing water heat loss is from snow caused by water. This is the amount of heat lost from the marker as it flows down.

It is clear from Figure 4 that the ground temperature around the heat pipe is raised by the underground heat pipe.The basic structure and operating principle of the heat pipe is detailed in Japanese Patent No. 482141 (Japanese Patent Publication No. 7278/1978). As described above, an appropriate amount of working fluid is depressurized and sealed in a closed tube whose inner wall is equipped with a wick material having capillary force, and one end is used as a heating evaporation section and the other end is used as a cooling and condensation section for heat transfer. Aside from the case where this heat pipe is placed horizontally and used, it is also possible to use a bottom heat pipe placed vertically so that the lower part serves as the heating and evaporating part and the upper part serves as the cooling and condensing part. In some cases, the flow of condensate from the upper part to the lower evaporation part uses the action of gravity, making it unnecessary to use an expensive wick material, especially in the case of a long vertical wick material as in the present invention. A wickless so-called steam siphon type is suitable for this purpose.

However, rather than being completely wickless, if a wick is inserted into the inner wall of the pipe corresponding to the length of the rib provided on the outer circumferential surface of an underground earth heat pipe, the condensate flowing down will be re-evaporated on its way back to the bottom of the pipe. This also means that it can be more effective.

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a front view when the enlarged condensing surface portion located on the back side of the sign surface of the traffic sign according to the present invention is made into a tycoon shape, and Fig. 2 is a vertical side view of Fig. 1, in which pipes to be used as posts are shown. 2 is long, so it is shown in a shortened state by being cut halfway in the figure.

1 is a sign and a heat pipe 2 is a post next to traffic route R.
, and has a sign surface 3 on one side.

This sign is also installed above the traffic route through the gate frame.
A heat pipe may also be connected to this.

The display 4 on this sign surface varies depending on the role played by the sign 1.
As shown in the figure, the display includes a numerical display of the speed limit, a slope display, a graphic display to notify dangerous areas such as falling rocks and curves, a reflective display (curve mirror) where the surface 3 itself serves as a display, and a display placed on the surface 3. This includes fluorescent reflection display (delinièque) through a lens.

An enlarged condensing surface portion 5 at the condensing side end of the heat pipe 2 is positioned on the back side of this surface 3.

In the illustrated example, the condensing surface section 5 is a circular thin hollow metal box container (Tyco type), and the sign 1 may be the one side plate of this container, and a separately prepared sign is attached to the outer side of the one side plate of this container. It may also be attached to.

A long pipe 2 whose bottom surface is sealed with a seal cap 6 is connected to the center of the lower part of the condensing surface section 5 so that the inside thereof is communicated with each other to form a closed container.

Then, after deaerating the inside of this Tyco-shaped sealed container 5, an appropriate amount of working fluid 7 is sealed to make the whole into a heat pipe, and furthermore, only one surface (the back side) of the Tyco-shaped container 5 is covered with heat insulating material 8.
is coated, and one side not covered with the heat insulating material is designated as the sign surface 3.

As a traffic sign post, the height of sign surface 3 is 1 from the ground level.
．． Depending on the pipe surface exposed above the ground and the conditions of the cold region, a frozen layer of about 0.7 m below the ground surface is formed, so the insulation material is used for a length that includes the thickness of this frozen layer. 8, and a plurality of ribs 9 are provided over the entire outer circumference of the lower earth heat pipe portion that is not covered with the heat insulating material 8 for the purpose of reinforcing it and increasing the heat receiving area.

In addition, a wick 10 made of all-mesh or the like may be inserted into the inner wall surface of the pipe 2 provided with the ribs 9, as shown in the enlarged cross section A--A of FIG. 1 in FIG.

Figure 4 is a map of actually measured soil temperature distribution in the northern Tohoku region, and it is clear from this map that there is a difference between the soil temperature distribution without heat pipes and the soil temperature distribution with buried heat pipes.

Therefore, it can be understood that the average soil temperature increases due to the action of the heat pipe.

Here, when ammonia is sealed as a working fluid in a Tyco type airtight container as a traffic sign post in the present invention,
The second type receives as an iron-ammonia type earth heat pipe.
A pressure vessel limitation occurs, which is calculated based on one example as follows.

1. Circular thin hollow metal box container dimensions: diameter 0.3m, thickness (width) 0.04m2, long pipe dimensions: 20A pressure piping outer diameter 27.2mm, inner diameter 2L4myn
, a wall thickness of 2.9 mm, a total length of 8 m, 5 m underground, and a maximum of 3 m above the ground surface.

The second type pressure vessel limit is -0.04 kg/CTL or less, which is determined by the ammonia pressure kg/CTL x container internal volume m3.

Therefore, the internal volume of the circular thin hollow metal box container is equivalent to the 8 m length of the 2OA pipe, so the total internal volume is 5.68 x 10 -3 m 3 .

And even if the ammonia pressure at 12℃ is 7kg/crl, 5.68X10-3X7kg/ff1=0.03981
y/ffl, which is below the limit, so it does not fall under the category of a second-class pressure vessel.

Furthermore, as for the heat input from the ground to the earth heat pipe, when the temperature of the ground is around 10°C, an experimental value of 0.037 W/cm2 per heat pipe surface area has been obtained.

Therefore, as shown in Fig. 3, a 2OA pipe 2 (outer diameter 27.
2mm, inner diameter 21.4mm, wall thickness 2.9mm) with four ribs 5 of 10mm width x 2mm thickness attached to the outer circumferential surface, and the total surface area at 1m length is calculated as (2.72cm square π ×10cm)+(1cmx4X2X
100cm)×0.8=1494ffl.

(Note) 0.8 in the above formula is the rib efficiency.

Therefore, per 1m of heat pipe, 0.037W/ff1X1494ffl=55.3W, and even if the effective length of a 5m underground earth heat pipe is 4m, it becomes 55.3W/mX4m=221W/total heat input0. As shown in the left road diagram in Figure 4, ice formation can be prevented by heat radiation from the sign surface using geothermal heat.

In other words, the working fluid 7 in the long earth heat pipe buried underground is evaporated from the bottom by geothermal heat and flows upward, as shown by the arrow in Figure 2, and flows upward into the circular shape at the top. It reaches the thin hollow metal box container 5 and condenses and liquefies on the inner surface facing away from the sign surface 3.

The latent heat generated at this time warms the entire sign surface 3, thereby melting the ice and snow adhering to the surface.

The liquefied working fluid then flows down the inner wall of the pipe 2 and returns to the evaporation section below.

Thereafter, the cycle of reevaporation and reflux is repeated in the same manner, so that the marking surface 3 always maintains its sharpness.

FIG. 5 is a schematic diagram showing the mounting arrangement of a guardrail and a delineator provided on a road side.

The guardrail 11 is fixed to the guardrail mounting pipe 12 as before, but a pre-eater 1' connected to a small diameter heat pipe 21 is inserted into this guardrail mounting pipe, and this heat pipe 2' is connected to the ground. It was buried inside.

This delineator 1' has a small diameter fluorescent marking surface 3',
It is also structurally similar to that shown in FIGS. 1 and 2.

FIG. 6 is a perspective view of a general road, which schematically shows a state consisting of a median strip 13, a road surface 14, and a guardrail 11. Inside the guardrail 11 is a fluorescent light with a heat pipe according to the present invention.

Traffic signs 1 are arranged at appropriate intervals along a pre-eater 1' having a sign surface 3' and a guardrail 11, and are also arranged in the same manner on the median strip.

FIG. 7 is a longitudinal sectional side view showing the structure of the curved mirror according to the present invention, and similarly, the working fluid vapor from the long ground pipe 2 is caused by geothermal heat to back up against the marking surface 3' of the curved mirror 1''. This shows that freezing of the marking surface g' of the mirror can be prevented by condensing and dissipating heat on the facing surface.

In addition, 15 in the figure is an anti-glare sleeve.

FIG. 8 shows the skeleton of the enlarged condensing surface portion of the heat pipe corresponding to FIG. 1.

In this case, a multiple round ring type, FIG. 9 shows a square ring type, and FIG. 10 shows a multi-branched type.

The branching pipe used at this time may be a square cross-section pipe, a flat pipe, or a round pipe.

Even in the case of a collapse, geothermal heat is radiated through the pipe 2 at the enlarged condensing surface section, heating the sign surface that should be located in front.

As described above, according to the present invention, it is possible to warm the sign surface using geothermal heat pipe temperature and remove ice and snow accretion on the surface.

Therefore, this is a method and device that can easily prevent signs from becoming unclear in the winter, and since the heat source uses geothermal heat using heat pipes, the heat source is not fake, and there are no mechanical moving parts, so maintenance is easy. This can help prevent traffic accidents by measuring the reduction in the burden on car drivers.
This is an excellent invention that can have great effects.

[Brief explanation of drawings]

Figure 1 is a front view of the traffic sign post according to the present invention, Figure 2 is a front view of the traffic sign post according to the present invention;
The figure is a vertical side view of Fig. 1, and Fig. 3 is A--A in Fig. 1.
A enlarged cross-sectional view, Figure 4 is a soil temperature distribution map, Figure 5 is a schematic diagram of the installation of guardrails and delineators installed on the side of the road, Figure 6 is a perspective view of a general road, and Figure 7 is a curved view as another application example. A longitudinal side view showing the structure of the mirror, Figure 8 is the first
This shows the skeleton of the heat pipe condensing section corresponding to the figure.
The round ring type, Figure 9 also shows the square ring type, and Figure 10 also shows the school regulations. 1.1', f... sign, 2... long pipe, 3゜3', 3''... sign surface, 5...
... Enlarged condensing surface section, 7... Working fluid, 8...
...Insulation material, 9...Rib, 10...Wick, GL...Ground surface.

Claims (1)

[Claims] 1. After positioning the enlarged condensing surface portion of the condensing end of the heat pipe on the back side of the sign surface of a sign installed regarding a traffic route, and deaerating the inside of this pipe and filling it with a working fluid. , the evaporation side of the pipe is inserted deep underground, the evaporation side pumps up geothermal heat, and the expanded condensation surface section radiates the heat, thereby heating the sign surface of a traffic sign. How to prevent ice and snow from accumulating. 2. A sign is installed regarding the traffic route, and the enlarged condensing surface of the condensing side end of the heat pipe is located behind the sign surface, and the evaporation side of this pipe is inserted and buried underground, and the inside of this pipe is removed. It is characterized by the fact that the externally exposed part of the pipe and the part underground to an appropriate depth are covered with a heat insulating material. Snow prevention device. 3. The sign surface of the traffic sign according to claim 2, wherein the enlarged and condensed surface portion is formed in a circular or square thin hollow metal box (Tyco-shaped) made of a plate, and one outer surface of which is provided as the sign surface. Ice and snow prevention device. 4. Concentric arrangement of pipe-shaped rings of the same type and different diameters in the shape of a circle, square, or rhombus, etc., in which the enlarged condensing surface portion is connected to the end of the heat pipe on the same or parallel plane to the plane containing the end of the heat pipe and the pipe axis, or Claim 2 consisting of a branch-like arrangement, etc.
A device to prevent ice and snow from accumulating on the sign surface of the traffic sign mentioned in Section 1. 5. Icing on the sign surface of the traffic sign set forth in claim 2, in which a plurality of ribs are provided over the entire outer circumference of the portion of the pipe inserted and buried underground that is not covered with the heat insulating material; Snow accretion prevention device. 6. The device for preventing icing and snow from accumulating on the sign surface of a traffic sign according to claim 5, wherein a wick is provided only on the inner wall surface of the pipe portion provided with ribs.