CN201230208Y - Lightning prevention equipment - Google Patents
Lightning prevention equipment Download PDFInfo
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- CN201230208Y CN201230208Y CNU200820118780XU CN200820118780U CN201230208Y CN 201230208 Y CN201230208 Y CN 201230208Y CN U200820118780X U CNU200820118780X U CN U200820118780XU CN 200820118780 U CN200820118780 U CN 200820118780U CN 201230208 Y CN201230208 Y CN 201230208Y
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Abstract
The utility model aims to provide a lightning protection device for inhibiting, releasing and damping the thunderstorm static of an antenna feeder system and atmospheric discharge, which comprises a first capacitor, a second capacitor, a first plane inductance coil and a second plane inductance coil. The first plane inductance coil and the second plane inductance coil are in a plane spiral shape. Turns number is N and N is a natural number more than or equal to 1. The first coil and the second coil are supported by an insulating bracket made of crossed insulating material. Each retaining screw is provided with a corona discharge ring to prevent corona discharge. The first plane inductance coil and the second plane inductance coil are mounted in parallel oppositely with a distance. The first capacitor and the first plane inductance coil form a primary resonant tank; and the second capacitor and the second plane inductance coil form a secondary resonant tank.
Description
Technical field:
The utility model provides a kind of can be suppressed, release, damping is disturbed from the thunder and lightning of antenna transmission system and the thunder resisting equipment and the electronic installation of atmospheric discharge.
Background technology:
Thunder and lightning seals in transmitter, has a plurality of approach (power supply, signal transmission link, antenna transmission system or the like), but because the medium wave broadcast transmitting antenna, it is the principal element that causes transmitter to be struck by lightning that the thunder and lightning that antenna transmission system is introduced disturbs.
At present, it is the vertical antenna of effective value that the cross section is extensively adopted in medium wave broadcast, because the type antenna is non-ground connection head tower or steel mast structure, in as antenna radiator, is again that thunder and lightning disturbs, the good receptor of atmospheric discharge.Electrostatic induction between charged cloud layer and the earth forms the electric charge accumulation of transmitting antenna, and consequent high voltage conducts to transmitter through feeder line, causes mortality to threaten to transmitter, even bust.With the high-power MW Transmitting Station of Fujian China in 2004 was example, and once thunderbolt causes nearly more than 300 the RF Amplifier Module damage of 1.2MW high-power transmitter, not only causes the tremendous economic loss, and this transmitter is just recovered normal broadcast through a couple of days.Therefore, the lightning protection of medium wave broadcast antenna-feedback system since the beginning that the medium wave broadcast technology is used, is exactly the difficult point problem that this field must be faced.
The nearly more than ten years, the development of high power solid state amplifying circuit, power synthetic technique, maturation replace traditional high power valve circuit gradually with its high efficiency, long-life.Solid state transmitter has become the main flow of present transmitter product.On the other hand, there is fatal shortcoming again in the solid State Active device, and is very responsive to abnormal voltage, surge current, very easily causes the permanent inefficacy of device.Thereby the application of solid state transmitter has proposed requirements at the higher level to the lightning protection performance of transmitting chain.
Although several years ago the crossed field small size antenna was once fashionable for a time, because the restriction of aspects such as radiation efficiency, power capacity is not really applied.Use maximum still traditional non-ground connection vertical antennas.Even use the crossed field small size antenna, the radio frequency apparatus for preventing thunderbolt remains the preferred version that reduces the thunderbolt risk, saves maintenance cost.
In the prior art, the anti-thunder and lightning measure of antenna-feedback system is for adopting block capacitor in the matching network between transmitter and antenna.This method has following shortcoming:
The capacitance of block capacitor is chosen excessive, and lightning protection effect is poor; Choose too smallly, excessive to useful signal decay, the signal path bandwidth narrows down.
Select the air capacity plate antenna for use, satisfying under the condition of capacitance, the electric capacity volume is excessive; In a single day select pottery or vacuum capacitance for use, under the situation that satisfies power capacity and puncture voltage, cost is higher, and punctures, with permanent failure, can't recover voluntarily.
Choosing of capacitance brings unnecessary constraint for the design of matching network; Lightning protection effect depends on the specific design of matching network in the antenna-feedback system, lacks standard, can't form the standardized designs product.
In the prior art, the electrostatic leakage means adopt inductance coil to release over the ground.This method has following shortcoming:
Adopt isolated electrostatic leakage inductance coil, coefficient of self-inductance is big (mH～100mH order of magnitude), and the turn-to-turn distributed capacitance is bigger, and self-resonant frequency is lower, easily operating frequency is had a negative impact, and shows as debug difficulties.
Inductance coil double as electrostatic leakage coil in the matching network, coefficient of self-inductance is chosen the specific design that depends on matching network, and lightning protection effect depends on the specific design of matching network in the antenna-feedback system, lacks standard, can't form the standardized designs product.
For overcoming variety of issue of the prior art, goal of the invention of the present utility model provides a kind of inhibition that is used for the medium wave broadcast transmitting chain, releases, the thunder and lightning of damping antenna transmission system disturbs and the apparatus for preventing thunderbolt of atmospheric discharge.
Provide a kind of thunder resisting equipment that is used for the broadcast transmission link according to the utility model, it comprises, first capacitor, second capacitor, first plane inductive coil, second plane inductive coil, wherein, described first and second plane inductive coils, be the snail shape, the number of turn is N, and wherein, N is greater than or equal to 1 natural number; Described first and second plane inductive coils are supported by the insulating support that the insulating material of right-angled intersection constitutes, and each fixed screw all is equipped with the corona discharge ring, prevents corona discharge; Parallel, the relative installation of first and second plane inductive coils, and keep certain distance; First capacitor and described first plane inductive coil are formed the primary resonant loop, and second capacitor and described second plane inductive coil are formed the secondary resonance loop.
The used conductor of described first and second plane inductive coils is selected from down a kind of in the row conductor: copper, aluminium, copper covered steel, copper is silver-plated or the material of other high surface conductivity; The used insulating material of described coil support frame is selected from a kind of in the following material: the insulating material of polyethylene, epoxy resin, expoxy glass, laminar film plastics high mechanical properties, high insulation degree.
Described planar spiral inductor coil shape is a kind of in rectangle, square, circular, the rhombus snail shape.
The snail shape that described first plane inductive coil and described second plane inductive coil are formed can be identical or different.
The coefficient of self-inductance of described first plane inductive coil and described second plane inductive coil can be identical or different.
The corona discharge ring that described each fixed screw is equipped with is 1 or 2.
The quality factor in described primary resonant loop and described secondary resonance loop can be identical or different.
The secondary load impedance can equate with elementary input impedance or be unequal.
The apparatus for preventing thunderbolt that is used for the medium wave broadcast radio frequency link that the utility model provides has following beneficial effect:
1) adopts the mutual inductance coupling between transmitter and the antenna, the thunder and lightning energy of lower frequency composition is realized DC-isolation.Eliminate all unfavorable factors of capacitance.
2) adopt the inductance coil (being lower than 24uH) of small inductor amount to carry out electrostatic leakage, improve the self-resonant frequency of inductance coil.
3) adopt twice electrostatic leakage, guarantee better to release effect.
4) quality factor in the coefficient of self-inductance of inductance coil, the coupling coefficient between the coil, primary/secondary loop, the three is interrelated, guarantee the interior coupling of band, the band attenuation index of apparatus for preventing thunderbolt, there is not dependence with apparatus for preventing thunderbolt external circuit component parameters, guarantees consistent lightning protection effect.
Inductance coil adopts the rectangle plane coil.Plane inductive coil has guaranteed the coupling coefficient of the maximum between the coil.Subsequent analysis shows, high coupling coefficient is the unique conditional that obtains rapid damping, and rapid damping is a standard of weighing all static leakage circuit lightning protection characteristics.Traditional three-dimensional helical coil, under the situation about coefficient of self-inductance 20uH, coupling coefficient generally can accomplish 0.05～0.08; The planar coil of identical coefficient of self-inductance, in safe distance (150mm), coupling coefficient can reach more than 0.25.Plane inductive coil adopts rectangle, has reduced installation volume.Each fixed screw between coil and insulation are supported is equipped with the corona discharge ring, reduces the corona discharge under the higher environment of relative humidity, avoids unnecessary signal energy loss, reduces band attenuation.The I/O impedance design of apparatus for preventing thunderbolt that the utility model provides is 50 Ω or 75 Ω of standard, also can customized 150 Ω or other I/O impedance, and to adapt to the antenna transmission system of all standards.Directly insert between antenna transmission system and the transmitter and can use, realized the standardization of product.
Description of drawings:
Fig. 1 is the circuit diagram according to apparatus for preventing thunderbolt of the present utility model;
Fig. 2 is according to rectangle plane spiral inductance coil schematic diagram of the present utility model;
Fig. 3 is according to rectangle plane spiral inductance coil of the present utility model;
Fig. 4 A is a Matlab simulation curve according to the input impedance of apparatus for preventing thunderbolt of the present utility model to Fig. 4 G;
Fig. 5 A is a Matlab simulation curve according to the input impedance of the transfer function of apparatus for preventing thunderbolt of the present utility model to Fig. 5 H;
Fig. 6 is the circuit connection diagram of test according to the damping characteristic of apparatus for preventing thunderbolt of the present utility model;
Fig. 7 is damping characteristic test curve figure.
Embodiment:
Antenna system meets with thunderbolt three kinds of principal modes:
1) direct lightning strike: the swift and violent electric discharge phenomena between the antenna on ground and charged cloud layer of towering.Huge discharging current or the high voltage that causes thus cause the damage of last stage of transmitter power device.
2) induction thunder or title secondary thunder:
In the direct lightning strike discharge process, powerful pulse current excites strong-electromagnetic field nearby, and antenna produces induced current as the good conductor in the strong-electromagnetic field on it, cause the damage of last stage of transmitter power device.
After direct lightning strike took place, the cloud layer electric charge disappeared, but because the inhomogeneities of discharge path resistance produces local high voltage, if antenna is positioned at local high-voltage region, caused the damage of last stage of transmitter power device equally.
3) spherical thunder: ball lightning directly drops on the antenna.Though the mechanism of production of spherical thunder it be not immediately clear that the factor that causes transmitter failure must be abnormal voltage or electric current.
In addition, atmospheric discharge also is a key factor that causes transmitter failure, does not cause enough attention at present as yet.Atmospheric discharge shows as the harm of transmitter; not seeing lightning, do not hearing under the situation of thunder, only is the little cloud layer of a slice antenna sky of sailing, and just transmitter has been produced harmful effect; gently then transmitter self-protecting, heavy then cause transmitter to damage.
Atmospheric discharge causes the principle of transmitter failure:
Charged cloud layer and antenna constitute the electric capacity of a distributed constant, and charged cloud layer, antenna as two electrodes of this electric capacity, owing to electrostatic induction, produce the electric charge with the cloud layer opposite polarity respectively on antenna.Because medium-wave antenna is non-ground connection shape antenna, unique discharge path can only be impedance matching network and transmitter between antenna and the earth.Unusual induced voltage and discharging current cause transmitter failure.
Apparatus for preventing thunderbolt lightning protection principle
No matter the thunderbolt of which kind of form, or atmospheric discharge, what transmitter was caused adverse effect all is three factors: charge inducing, abnormal voltage, surge current.
The lightning protection measures of antenna transmission system is nothing more than two kinds of measures: 1) isolate: the thunder and lightning forming process has determined the energy of lightning current or voltage mainly to concentrate on lower frequency ranges, and stopping direct current is an effective lightning protected measure.2) release:, prevent that abnormal voltage from forming or reducing the life period of abnormal voltage for electrostatic charge or voltage provide the good path of releasing.The apparatus for preventing thunderbolt that is used for the medium wave broadcast radio frequency that the utility model provides, integrated application above-mentioned two kinds of measures.
Fig. 1 is the circuit diagram according to apparatus for preventing thunderbolt 1 of the present utility model.Because this apparatus for preventing thunderbolt is used for the broadcast transmission link, present bandpass characteristics at frequency domain, called after radio frequency band filter again, it comprises, first capacitor 2, second capacitor, 3, the first plane inductive coils 4, second plane inductive coil 5, wherein, described first and second plane inductive coils 4 and 5, spiral-shaped for rectangle plane, the number of turn is N (N is greater than or equal to 1 natural number); First plane inductive coil 4 and second plane inductive coil 5 are supported by the insulating support that the insulating material of right-angled intersection constitutes, and fix with screw, and each fixed screw all is equipped with the corona discharge ring, and this discharge ring can also can prevent corona discharge for 2 for 1; Parallel, the relative installation of first and second plane inductive coils, and keep certain distance, this distance is greater than the arcing distance of operational environment (height above sea level, atmospheric pressure, relative humidity, maximum operating voltage).
The snail shape that first plane inductive coil 4 is formed can be identical or different with the snail shape of second plane inductive coil, 5 compositions, except that being the rectangle, can also be a kind of in square, circular, the rhombus snail shape.Their coefficient of self-inductance can be identical, also can be different.
Resistance R L among Fig. 1 is the load impedance in the secondary resonance loop of apparatus for preventing thunderbolt, i.e. the input impedance of antenna transmission system can be 50 Ω, 75 Ω, 150 Ω ..., it can equate with the input impedance in primary resonant loop, also can be unequal.Do not have direct connection between two inductance coils, signal energy is coupled by mutual inductance, and the thunder and lightning of lower frequency composition is realized effectively isolating.Two coils constitute electrostatic leakage path elementary, the secondary loop again respectively, further reduce the thunder and lightning energy that seals in transmitter.
This circuit can be applied to actual medium wave broadcast transmitting chain, and precondition is: alap band attenuation; Smooth as far as possible band attenuation characteristic; Matching properties in the good band.
Fig. 2 is according to rectangle plane spiral inductance coil schematic diagram of the present utility model.Fig. 3 is the planar spiral inductor coil of the utility model after installing.This planar spiral inductor coil is to make like this:
1) according to the plant capacity grade, choose suitable fine copper tubing and quarter bend, need to consider following factor usually:
A. copper pipe cross section external diameter, wall thickness, copper purity
B. quarter bend cross sectional inner diameter, wall thickness, copper purity.
2) according to the design size of plane inductive coil, block copper pipe.
3) copper pipe, the quarter bend after will blocking is fixed in particular manufacturing craft.
4) welding.Use brazing technology, weld the quarter bend of four jiaos of the every circles of plane inductive coil one by one, make it closely to weld together to form planar spiral winding with copper pipe.
5) with planar spiral winding polishing, polishing.
6) to the planar spiral winding punching, be used for fixing screw.
7) insulating material is blocked, digs and mill according to design shape and size.
8) to the insulating material punching, be used for fixing screw.
9) assembling.Helical coil, insulation bracing frame, corona discharge ring are assembled together with screw.
Plane inductive coil in the described apparatus for preventing thunderbolt is the path of releasing of lightening pulse, is again the carrier of radio frequency loop current, thereby is main power consumption, heater members in the equipment, has directly determined effectiveness, temperature in chassis.Therefore the conductivity of manufactured materials is had relatively high expectations.Usually the above power grade of 100KW adopts the manufacturing of copper silver plating process; 10KW～100KW power grade adopts the fine copper manufacturing; 3KW～10KW power grade can adopt the manufacturing of copper covered steel technology; The following power grade of 3KW can adopt the aluminium manufacturing.
The insulation bracing frame that is used for fixing plane inductive coil has two aspects and requires:
The requirement of electric insulation degree.
Because the plane inductive coil number of turn is less, carry stronger radio-frequency current and thunder and lightning leakage current again, other application scenario of turn-to-turn voltage ratio will exceed 1～2 order of magnitude, thereby requires insulating support to have good electrical insulative property.
Requirement of mechanical strength.
Thunder and lightning, atmospheric discharge act on plane inductive coil, and inductance coil has strong entad tendencies toward shrinkage, and insulating support bears big stress, must have enough big rigidity to resist the deformation of inductance coil.In a single day deformation take place in inductance coil, and the coefficient of self-inductance of self, the coupled systemes number average between the coil will change thereupon, and the circuit constraint equation is no longer set up, and transmitter constituted mortality threaten.
Given this, the insulation bracing frame of plane inductive coil is looked power grade and is selected polyethylene, epoxy resin, expoxy glass, laminar film plastics for use.
The corona discharge ring is to be made by electric conducting material.Outer surface is an oblate spheroid, offers groove in the one side that diameter is less, and opens a through hole less than groove diameter by groove, is used for fixing screw.When being fixed to plane inductive coil on the insulating support, the screw top is positioned at the groove of corona discharge ring, shielded by the corona discharge ring, not can with other conductive discharge in the surrounding environment.The corona discharge ring outer surface guarantees to present maximum outer surface curvature radius through computer simulation, emulation under certain volume.
Hereinafter elaborate the index of weighing this circuit lightning protection characteristic, this index damping coefficient that is as the criterion.
For guaranteeing minimum band attenuation, elementary, secondary two loops are under the condition of isolated circuit, and promptly two loops do not exist under the condition of coupling each other, debug two isolated circuits respectively, make the equal resonance in two loops in operating frequency.In the actual debug process, make the inductive secondary open circuit, then primary coil is isolated circuit; Make the inductive primary open circuit, then the secondary loop is isolated circuit.
For satisfying matching properties in the most smooth band attenuation characteristic and the good band, the coupling coefficient K between loop quality factor (be Q value, for ease of debugging, the employing symmetrical network, equal Q value is got in elementary, secondary loop) and two inductance coils must satisfy:
Under given I/O impedance conditions, can obtain suitable Q value by the tap position of adjusting inductance coil.When satisfying following condition at the same time:
Isolated primary return, the isolated equal resonance in secondary loop are in operating frequency; Coupling coefficient K between loop Q value, the inductance coil satisfies (1) formula.
Entire circuit has following characteristic so: entire circuit, see into that from input still resonance is in operating frequency.Entire circuit is seen into from input, and the input impedance of corresponding operating frequency equals load impedance, i.e. Z
i=R
i=R
L
Input impedance to the functional relation of frequency is:
(2) ξ is normalized frequency (ξ=f/f with respect to operating frequency in the formula
0), by (2) formula, can weigh the coupling bandwidth (such as being defined as maximum standing-wave ratio 1.2 bandwidth) of apparatus for preventing thunderbolt circuit.
With respect to the functional relation of normalized apparatus for preventing thunderbolt power output of transmitter available power and frequency (be in the scattering parameter | S
21|):
(3) Ri in the formula is the real part (being the input resistance part) of input impedance Zi.Can weigh the transmission bandwidth of apparatus for preventing thunderbolt by (2), (3) formula.
Based on (2), (3) formula input impedance the Matlab simulation curve as Fig. 4 A to shown in Fig. 4 G.
The Matlab simulation curve of transfer function (mould value) as Fig. 5 A to shown in the 5H.
The lightning protection characteristic is according to a large amount of practical experiences, with approximate measurement of the rate of decay of impulse response voltage waveform.The decay of impulse response voltage waveform is fast more, and the electrostatic leakage effect is good more.
The impulse response method of testing as shown in Figure 6.Among Fig. 6, oscilloscope 6 is received apparatus for preventing thunderbolt 1 of the present utility model, i.e. the input 8 of measured device, and pulse generator 7 is received apparatus for preventing thunderbolt 1, i.e. the output 9 of measured device.
At tested filter (promptly, apparatus for preventing thunderbolt) the rectangle burst pulse of output feed-in repetition rate 10KHz, occupation efficiency 0.5%, because the resonance characteristic of tested filter, to obtain the sine pulse string of amplitude at input according to approximate index law decay, pure oscillation frequency theory value should equal the centre frequency of tested filter, and the pulse train existing frequency that goes out to appear again is the repetition rate of the burst pulse of pulse generator output.The timing definition of each pulse train from peak atenuation to 37% peak value is the damping time of impulse response.
Fig. 7 is damping characteristic test curve figure.The resistance of input, output is build-out resistor, is used to ensure the impedance matching of measured device.
From above-mentioned no matter be frequency bandwidth based on (2), (3) formula simulation curve Fig. 5 A as can be known by the matching properties definition to 5H,, all be the subtraction function of Q value, the increasing function of coupling coefficient still by the frequency bandwidth of transmission characteristic definition.According to the corresponding relation of circuit time domain specification and frequency domain characteristic, the frequency bandwidth of broad in the frequency domain, the rate of decay (less time constant) faster in the inevitable corresponding time domain.
Hence one can see that, and the unique channel that obtains good electrostatic leakage performance is the coupling coefficient K (reducing loop Q value simultaneously) that increases between the inductance coil, the basic reason of Here it is employing planar spiral winding.
When obtaining good electrostatic leakage characteristic, must be accompanied by the broadening of apparatus for preventing thunderbolt frequency bandwidth.The broadening of coupling bandwidth helps the coupling between the transmitting chain each several part; The broadening of transmission bandwidth, favourable to guaranteeing transmitter audio frequency corresponding index.
Using planar spiral inductance coil, about operating frequency 1MHz, apparatus for preventing thunderbolt can be accomplished more than the 120KHz by the 2dB bandwidth of characteristic.Use traditional three-dimensional helical coil, the bandwidth under the similarity condition accomplishes that 25KHz is very difficult.
Apparatus for preventing thunderbolt in the medium wave broadcast transmitting chain provided by the utility model is not born filtering, frequency-selecting effectiveness, so the filtering degree is not done any requirement.
The used conductor of the utility model plane inductive coil except that be selected from copper, aluminium, copper covered steel, copper silver-plated, can also select the material of other high surface conductivity; Inductance coil insulating support material is except that selecting: polyethylene, epoxy resin, expoxy glass, the laminar film plastics (SMC), and other insulating material of also optional high mechanical properties, high insulation degree.
Many electronic installations as transmitter etc., can be installed apparatus for preventing thunderbolt of the present utility model, with suppress, release, damping disturbs and atmospheric discharge from the thunder and lightning of antenna transmission system, electronic installation is played a very good protection.
Though the utility model is to make an explanation by the embodiment shown in the above-mentioned accompanying drawing.But it should be appreciated by those skilled in the art that the utility model is not limited to these embodiment, but covered various variations or the modification that does not break away from spirit of the present utility model.Thereby scope of the present utility model is limited by appended claims and equivalent thereof.
Claims (8)
1, a kind of thunder resisting equipment that is used for the broadcast transmission link, it comprises, first capacitor, second capacitor, first plane inductive coil, second plane inductive coil, wherein,
Described first and second plane inductive coils are the snail shape, and the number of turn is N, and wherein, N is greater than or equal to 1 natural number;
Described first and second plane inductive coils are supported by the insulating support that the insulating material of right-angled intersection constitutes, and each fixed screw all is equipped with the corona discharge ring, prevents corona discharge;
Parallel, the relative installation of first and second plane inductive coils, and keep certain distance;
First capacitor and described first plane inductive coil are formed the primary resonant loop, and second capacitor and described second plane inductive coil are formed the secondary resonance loop.
2, according to the thunder resisting equipment of claim 1, it is characterized in that: the used conductor of described first and second plane inductive coils is selected from down a kind of in the row conductor: copper, aluminium, copper covered steel, copper are silver-plated; The used insulating material of described coil insulation support is selected from a kind of in the following material: polyethylene, epoxy resin, expoxy glass, laminar film plastics.
According to the thunder resisting equipment of claim 1, it is characterized in that 3, described planar spiral inductor coil shape is a kind of in rectangle, square, circular, the rhombus snail shape.
According to the arbitrary thunder resisting equipment in the claim 1-3, it is characterized in that 4, the snail shape that described first plane inductive coil and described second plane inductive coil are formed can be identical or different.
According to the arbitrary thunder resisting equipment in the claim 1-3, it is characterized in that 5, the coefficient of self-inductance of described first plane inductive coil and described second plane inductive coil can be identical or different.
According to the arbitrary apparatus for preventing thunderbolt in the claim 1-3, it is characterized in that 6, the corona discharge ring that described each fixed screw is equipped with is 1 or 2.
According to the arbitrary thunder resisting equipment in the claim 1-3, it is characterized in that 7, the quality factor in described primary resonant loop and described secondary resonance loop can be identical or different.
According to the arbitrary thunder resisting equipment in the claim 1-3, it is characterized in that 8, the secondary load impedance can equate with elementary input impedance or be unequal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200820118780XU CN201230208Y (en) | 2008-06-05 | 2008-06-05 | Lightning prevention equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200820118780XU CN201230208Y (en) | 2008-06-05 | 2008-06-05 | Lightning prevention equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201230208Y true CN201230208Y (en) | 2009-04-29 |
Family
ID=40635151
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU200820118780XU Expired - Fee Related CN201230208Y (en) | 2008-06-05 | 2008-06-05 | Lightning prevention equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201230208Y (en) |
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2008
- 2008-06-05 CN CNU200820118780XU patent/CN201230208Y/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090429 Termination date: 20140605 |