JP2003317995A - Lightning rod member and lightning rod using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a member suitable for a lighting rod, having excellent arc resistance and corrosion resistance used as a structural member for the whole lightning rod or the tip of the lightning rod, and to provide the lightning rod using it. <P>SOLUTION: This lightning rod member is composed of one of a W-Mo alloy, a doped tungsten, a cerium oxide-added W, a Re-W alloy, a Ta-W alloy, a thorium oxide-added W and a cerium oxide-added Mo. By installing the member to the lightning rod tip or using the member as the structural member for the whole lightning rod, deformation and reduction of conductivity caused by a thunderbolt are extremely small, so that the member or the lightning rod can maintain a function as the lightning rod over a long period. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to excellent arc resistance used as a tip or the whole of a lightning rod,
A member suitable for a lightning rod having corrosion resistance and a lightning rod using the member.

[0002]

2. Description of the Related Art Copper, corrosion-resistant aluminum, steel materials and stainless alloys have been used for conventional lightning rods. However, the melting point of each of these materials is as low as 2000 ° C. or lower, and in an environment where repeated lightning strikes occur, melting occurs from the tip that becomes hot, the tip shape collapses, and it becomes difficult to collect the lightning strike on the lightning rod. Further, even if the plating is performed mainly with chromium or nickel to improve the corrosion resistance, repeated lightning strikes cause the plating to peel off due to its low melting point, making it impossible to maintain the corrosion resistance. Therefore, JP-A-11
No.
A lightning rod has been proposed in which a tip made of metal having a temperature of 00 ° C. or higher is attached to the tip. In this invention, tungsten,
Tungsten-silver alloy and tungsten-copper alloy are mentioned. However, when a tungsten tip is used as the tip of a lightning rod, the structure recrystallizes and becomes fragile once a lightning strike occurs and it is exposed to high temperatures. When a lightning strike is applied to the brittle tip, the tip easily breaks. Further, in order to use it at a place where it rotates at high speed (for example, the tip of a blade of wind power generation), it is necessary to increase the diameter in order to compensate for brittleness. Since tungsten and a tungsten alloy are expensive, they are disadvantageous in terms of cost, and the weight of the lightning rod is disadvantageous when used for a blade or the like. When a tungsten-silver alloy or a tungsten-copper alloy is used as the tip of the lightning rod, the lightning strike melts silver and copper, and some sublimation occurs. It flows out and sticks. Further, since the skeleton-shaped tungsten remaining at the tip is heated to the recrystallization temperature, it becomes brittle and cannot be used for a long time or in a place where it rotates at high speed.

A member used as the tip or body of the lightning rod is made of a material having excellent arc resistance and corrosion resistance, so that a long life can be obtained and the surrounding lightning strike can be efficiently directed to the lightning rod. We propose the material of the lightning rod member used for the tip of the lightning rod that is concentrated by the lightning.

[0003]

The present invention according to claim 1 provides a W-Mo alloy and doped tungsten (K, Al, S).
i, tungsten containing 0.1 to several hundreds of ppm of a doping agent such as Ca), cerium oxide-added W, Re-W alloy, Ta-W alloy, thorium oxide-added W, or cerium oxide-added Mo. A characteristic lightning rod member. All of these materials are resistant to corrosion and have high melting points. Even when exposed to a lightning strike, the shape can be maintained even if repeated lightning strikes occur without melting and sublimation as compared with low melting point metals and alloys such as iron materials and stainless steel. Further, the temperature rises to a temperature higher than the recrystallization temperature during a lightning strike, but the material used for the lightning rod member of the present invention can maintain strength and impact resistance even after recrystallization, so the tip shape against repeated lightning strikes The function of collecting lightning can be maintained for a long period of time without changing. The present invention according to claim 2 provides at least a W-Mo alloy, doped tungsten, cerium oxide-added W, Re-W alloy, Ta.
-W alloy, W containing thorium oxide, Mo containing cerium oxide
The lightning rod is characterized in that it has a lightning rod member of any one of the above at its tip or is configured as a whole.
Each of the lightning rods of the present invention is resistant to corrosion and has a high melting point. Therefore, even when exposed to a lightning strike, the shape can be maintained even after repeated lightning strikes without melting and sublimation as compared with low melting point metals and alloys such as iron materials and stainless steel. Further, when lightning strikes, the temperature rises to the recrystallization temperature or higher, but since the material used for the tip of the lightning rod of the present invention can maintain strength and impact resistance even after recrystallization, the tip is resistant to repeated lightning strikes. The function of collecting lightning strikes can be maintained for a long time without changing the shape.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION The lightning rod member of the present invention can be obtained by the following procedure. W, Mo, Ce, Re, T
Powders of a, a doping agent (K, Al, Si, Ca, etc.) are mixed in a desired composition by a dry or wet mixer, and mixed powder is prepared by a method such as rubber pressing or CIP (cold isostatic pressing). It is pressed into a rod shape. Next, electrodes are attached to both ends of the molded body, and a current of 2000 to 10000 (A) is applied to
By heating up to a temperature range of 500 ° C to 3150 ° C, electric current sintering is performed to obtain an ingot having a relative density of 60 to 99%. Next, the sintered body ingot is cut according to the length of the lightning rod member to obtain a cylindrical sintered body. As another method, a method of press-molding the mixed powder into a final shape and sintering at 1800 to 3000 ° C. in a non-oxidizing atmosphere,
There is a method of sintering by a hot press method. The sintered body obtained by the above method can be machined by a cylindrical grinder, a universal grinder or the like to obtain a lightning rod member. In the lightning rod of the present invention, the lightning rod member obtained by the above method is joined to the metal conductive shaft or the like by means such as welding, brazing, friction welding, diffusion welding, or screwing. Is obtained by Further, when the entire lightning rod is manufactured, it can be manufactured by the same method.

[0005]

[Example] Example 70 original Mo powders with a purity of 99.95% and an average particle size of 3 μm
%, W powder with a purity of 99.9% and an average particle size of 2 μm
Atomic% and Henschel mixer for 30 minutes to obtain
The powder obtained by a rubber press machine at 800 Kgf / mm^Two
Shaped by applying pressure of φ15 (mm), length 60
A pressed body of 0 (mm) was obtained. Both ends of the obtained pressed body
Attach the electrode to the
Electrical sintering was performed at a high temperature of 2500 ° C. Obtained by electrical sintering
With a diameter of φ12 (mm) and a length of 500 (mm)
Cut with a wheel containing silicon carbide abrasive grains, and then
Grinding with a universal grinding machine using a diamond wheel
The bottom diameter is 10 (mm) and the length is 30
(Mm) conical Mo-W alloy chips were obtained. this
Mount the conical Mo-W alloy tip 1 on the stainless steel
A lightning rod was manufactured by joining the wire portion 3 and the silver brazing 2 together.
3 of wind power generator which installed lightning rod which we made in paddy field area
Attach to the tip of the blade part 5 of the book and attach the tip of the shaft 3
Connect the grounding conductor to the opposite side (ground side) from the attached end.
It was connected and the end of the conductor was buried in the ground. Electricity during a lightning strike
Is grounded at the buried part 5 through the conductor 4 from the lightning rod.
It Due to the nature of lightning, there is nothing tall around it,
It is easy to fall on conductive materials. Wind power generation in paddy fields
The electrical equipment fits well in these conditions and is extremely
Many. Experiments were conducted around tall buildings and trees such as steel towers and power poles.
It was conducted on a wind power generator installed in a paddy field where there is no equality.
The lightning rod with the tip has three blades as shown in FIG.
Attached to the tip 7 of the blade of the wind power generator with
For three lightning rods during that period.
The total was 423 times. When observing the chip after use
Around the surface, the entire surface was oxidized and discolored by precipitation.
However, there was no deformation, and when I measured the diameter with a caliper, it was before operation
It didn't change. In addition, the tissue is re-exposed due to the high temperature of lightning strike.
Crystallization occurred, but this alloy had brittle fracture even after recrystallization.
Is hard to cause and there is no problem in strength and impact resistance
It was Also, the tip had an average of 130 lightning strikes.
Despite that, the cone shape is maintained and the tip shape does not change.
won. In addition to the wind turbine generator itself, its vicinity
There is no lightning during the operation period (within a radius of 100 m) and lightning protection
The performance as a needle was maintained. Also, change the material of the chip
Tungsten and oxide oxide doped with Al, Si, Ca, etc.
W-added W, Re-W alloy, W-added thorium oxide and
And Mo with cerium oxide added, the same effect was obtained.
The result was shown. In addition, the above-mentioned experiment is so-called Franklin Ro
It is a rod type lightning rod, but it has a wider effect
Even when used in a so-called pre-vectron type lightning rod
It showed the same excellent characteristics. Comparative Example 1 (Tungsten) W powder with a purity of 99.95% and an average particle size of 3 μm was
-800 Kgf / mm with press machine²Apply pressure to adjust
Shaped, diameter 15 mm (mm), length 600 (mm)
I got a body. Attach electrodes to both ends of the obtained pressed body
K, 4000 (A) voltage (current) is added and the maximum is 2500
Electric current sintering was performed at ℃. The diameter obtained by electric current sintering is φ
Carbonize 12 (mm), 500 (mm) long ingot
Cut with a wheel that has silicon abrasive grains, and then use a diamond
Use a universal wheel to grind with a hand wheel.
A circle with a bottom diameter of 10 (mm) and a length of 30 (mm)
A conical tungsten lightning rod member was obtained. This cone
Shaped tungsten tip 1 with stainless steel shaft
A lightning rod was manufactured by joining the part 3 and the silver brazing 2 together. Production
Of the wind power generator installed in the paddy field
Attach to the tip of the blade part 5 and remove the tip of the shaft 3.
Connect the grounding wire 4 to the side opposite to the attached end (ground side).
Then, the end 5 of the conductor was buried in the ground. Electricity during a lightning strike
Is grounded at the buried part 5 through the conductor 4 from the lightning rod.
It Due to the nature of lightning, there is nothing tall around it,
It is easy to fall on conductive materials. Wind power generation in paddy fields
The electrical equipment fits well in these conditions and is extremely
Many. Experiments were conducted around tall buildings and trees such as steel towers and power poles.
It was conducted on a wind power generator installed in a paddy field where there is no equality.
The lightning rod with the tip has three blades as shown in FIG.
Attached to the tip portion 7 of the blade of the wind power generator. This
Of the lightning rod was operated for one year, and three lightning rods were in the meantime.
The total number of lightning strikes was 407. Material for lightning rod
Upon observation, the entire surface was oxidized and changed due to precipitation.
It is colored, and it is affected by lightning shock and wind pressure, and blade acceleration and deceleration.
6 mm from the tip was missing. The remaining tissue
Observation revealed that recrystallization had occurred and it was a very brittle group.
It was woven. In addition, oxidation progresses to the melted part at the tip.
However, when 10 months have passed, wind power is not emitted from the lightning rod.
There are three lightning strikes on the upper end 6 of the electronic device body
The ability to focus on the needle was clearly diminished. As a result
Therefore, the tungsten tip is a lightning rod for a long time
Is difficult to use as a lightning rod member
Do you get it. Comparative Example 2 (copper-tungsten) 80% W powder with a purity of 99.95% and an average particle size of 3 μm
% With a die press machine at 1000 kgf / mm^TwoThe pressure of
In addition, it was shaped to have a bottom diameter of 10 (mm) and a length of 30 (m
A conical press body of m) was obtained. Press the body at 1500 ℃
Necking of adjacent particles in a hydrogen gas atmosphere
The so-called pre-sintered state is caused. Relative at this time
The density was 65%. This temporary sintered body is called a skeleton
In a hydrogen gas atmosphere at 1100 ° C. to infiltrate copper
Scraped copper on the surface without dipping with sandpaper
After removing, the end face is ground with a grinder to obtain a lightning rod member.
It was Next, use a brazing agent to attach the tip to the stainless steel
A lightning rod is manufactured by joining the shaft part 3 and the silver brazing 2 together.
It was The experiment was carried out around tall buildings such as steel towers and electric poles, trees, etc.
It was conducted on the wind power generator installed in the paddy field. Product
A wind turbine with three lightning rods, as shown in Fig. 2.
Attached to the tips of the three blades 5 of the power generator, the shaft
The side opposite to the end where the lightning rod member 3 is attached (ground side)
Connect the grounding conductor 4 to the and connect the end 5 of the conductor to the ground.
I set it up. The electricity at the time of lightning strike is buried through the conductor 4 from the lightning rod.
Grounded at installation 5. Wind the lightning rod with the tip
Attached to the tip of the blade of the power generator and earned for a year
The total number of lightning strikes on the three lightning rods during that time is 42
It was 9 times. In addition, oxidation progresses to the melted part at the tip.
And wind power generation that is not lightning rod after 10 months
There are four lightning strikes on the upper end 6 of the device body.
His ability to concentrate on his eyes was clearly diminished. Lightning rod
When observing the material, shock and wind pressure at the time of lightning strike,
Acceleration / deceleration caused a loss of about 10 mm from the tip.
The molten copper was deposited around the remaining tip. The rest
Observation of the microstructure of the damaged part revealed that recrystallization had occurred.
And had a very brittle structure. Also, Cu-W is A
When g-W was used, similar results were obtained. Is this the result
Have been using Cu-W and Ag-W lightning rod members for a long time.
It is difficult to use it as the tip of a lightning rod.
I understood. Comparative Example 3 (stainless steel) Of SUS304 stainless steel shaft with a diameter of 10 mm
Similar to the first embodiment, the tip is processed by a lathe to make the tip sharp.
The cone shape was 10 mm in diameter and 30 mm in length. The experiment is
For paddy fields that do not have tall buildings such as steel towers and power poles or trees around
It carried out on the wind power generator provided. Fabricated lightning rod
2 of the wind power generator with three blades as shown in FIG.
Attach it to the tip of the blade 5 of the book and
Connect the grounding wire 4 to the other side (ground side), and connect the end of the wire.
Part 5 was buried in the ground. Electricity at the time of lightning strike is led from the lightning rod.
It is transmitted through the wire 4 and grounded at the buried portion 5. The lightning rod
The wind power generator with the
Installed in a paddy field where there is no
During that time, the total number of lightning strikes on the three lightning rods was 383 times.
Met. When observing the tip after operation,
The outer surface was not oxidized or discolored, but the tip shape was
Because the temperature was raised by the energy of the arc from lightning
Melted and melted about 100 mm from the tip
After that, the shape was broken. In addition, the part where the shape collapsed
When the electric resistance of was checked, it was 7.2 × 10 before the operation. ^-5
The electrical resistance, which was Ω · cm, was 3.5 × 10.⁷Ω · cm
It had risen in and was a material close to an insulator. this
Also from the point, deterioration as a lightning rod was observed. Also the tip
Oxidation has progressed to the melted part, and 10 months have passed
Twice on the upper end 6 of the wind turbine generator that is not the lightning rod
There is a lightning strike, and the ability to concentrate lightning on the lightning rod is clear
Was falling to. From this result, stainless steel lightning rod
Is said to be difficult to use for a long time in a lightning stricken environment
I found out.

[0006]

The lightning rod member made of any one of W-Mo alloy, doped tungsten, cerium oxide-added W, Re-W alloy, Ta-W alloy, thorium oxide-added W, and cerium oxide-added Mo is attached to the tip of the lightning rod. , Or as a component of the entire structure, it was possible to obtain a lightning rod that is extremely resistant to deformation and deterioration in conductivity due to a lightning strike and that can continue to function as a lightning rod for a long period of time.

[Brief description of drawings]

FIG. 1 shows shapes of a lightning rod member and a lightning rod of the present invention.

FIG. 2 shows a wind turbine generator with three blades

[Explanation of symbols]

1 Lightning rod member (chip) of the material of the present invention 2 Brazing part 3 Stainless steel shaft 4 conductors 5 Conductor embedded section 6 Lightning strikes to the generator unit 7 Lightning rod of the present invention

Claims (2)

[Claims] 1. A lightning rod member comprising any one of W-Mo alloy, doped tungsten, cerium oxide-added W, Re-W alloy, Ta-W alloy, thorium oxide-added W, and cerium oxide-added Mo. . 2. A lightning rod member made of at least one of W-Mo alloy, doped tungsten, cerium oxide-added W, Re-W alloy, Ta-W alloy, thorium oxide-added W, and cerium oxide-added Mo is provided at the tip. A lightning rod, characterized by having or constituting the whole.