Background technology
Ceramic gas discharge tube is that two electrode seal welds of in vacuum furnace, with silver-copper brazing alloy the Fe-Ni-Co alloy being processed are connected to two metallization ports of earthenware and the electric devices processed, before the sealing welding, in earthenware, is filled with the inert gas of mixing.The earthenware inner surface is decorated with four and the disjunct carbon line of metal layer with pencil; Electrode surface is coated with and is beneficial to electronic stability electrons emitted powder; Adjust the spacing of two electrodes and charge into the mixed inert gas gas pressure intensity in the pipe, can obtain the discharge tube of various technical performances.Ceramic gas discharge tube is widely used in being used for equipment and personnel are made overvoltage protection in all kinds of electronic apparatus circuits owing to have the good characteristic that discharge capacity is big, electric capacity is little, insulation resistance is high, especially anti-thunderbolt.
In practical application, the puncture voltage Vs that reduces ceramic gas discharge tube is an important research project to improve the fail safe of its object of protection.Influencing puncture voltage Vs size has various factors, comprises gaseous species, pressure values, electrode distance, cathode electronics material etc.Production practices have confirmed crust Xing Dinglv, and promptly under the situation that gaseous species, cathode material are all confirmed, puncture voltage Vs is the function of air pressure and pole span product in discharge space.Yet when having two kinds of gases to mix in the discharge tube, its punch-through is different with single gas of planting, and in discharge, Penning effect will occur.When for example in neon (Ne), sneaking into a spot of argon gas (Ar), can make the puncture voltage of gas be lower than the puncture voltage Vs of pure argon or pure neon.
According to above-mentioned physical phenomenon, current generally both at home and abroad earlier neon and argon gas are stored in the steel cylinder after by 3: 1 the molecular amounts mixed of fixing.The used aerating device of the method is as shown in Figure 1; Comprise heating and vacuum seal system 1, the precision pressure gauge 2 that is connected with said heating and vacuum seal system 1; The inflation inlet 4 of heating and vacuum seal system 1 is connected with a charging valve 3; Adopt the unlatching of hand-guided charging valve 3 or close the size of control inflation pressure.In the course of processing, processed product 5 piles up processing on the pedestal 6 that places heating and vacuum seal system 1 bottom, comprises vacuum degassing, filling with inert gas and sealing welding.Two utmost point discharge tubes by above-mentioned inflation method device is made are tested its Vs value generally about 70V by conventional method.This kind inflation method exists following not enough: the ratio of (1) two kind of mixed inert gas is generally fixed value, can not regulate on demand, can not realize accurate control to the technical parameter of discharge tube; (2) be stored in of the passing of the mist of the fixed mixing ratio in the steel cylinder along with service time; Gas ratio in the steel cylinder can change; The technical parameter of discharge tube changes thereupon in the production process thereby make, and especially the puncture voltage Vs of discharge tube changes greatly, and quality is restive; Generally about 70V, for many electronic apparatuss, this Vs value is too high, and still there is security threat in electronic apparatus for its Vs value of two utmost point discharge tubes of (3) making.
The content of invention
To the above-mentioned deficiency of existing inflation method, the applicant improves through research, and the inflation method of another kind of low pressure ceramic gas discharge tube is provided, and the ratio of two kinds of mixed inert gas can be regulated on demand, can realize accurate control to the technical parameter of discharge tube; The inventive method also provides the The Best Mixed ratio of two kinds of mixed inert gas, can reach lower dc breakdown voltage by the low pressure ceramic gas discharge tube of its making, and the applicant provides the aerating device of realizing this method simultaneously.
Technical scheme of the present invention is following:
A kind of inflation method of low pressure ceramic gas discharge tube; With two kinds of different electric ionization potentials single plant gas by molecular amounts than mixing in the burner hearth that charges into the vacuum seal brazier respectively; Mist gets into and places in the discharge tube of treating soldering and sealing of burner hearth, and electrode and the earthenware with discharge tube seals soldering and sealing at last.
Single kind gas of said two kinds of different electric ionization potentials is neon and argon gas, and wherein the shared molecular amounts of argon gas is 1.0~2.5%.
Concrete steps are following:
(1) be 1 * 10 with ceramic gas discharge tube to be processed in vacuum degree
-4P~5 * 10
-4Progressively be warming up to 720 ± 2 ℃ in the vacuum seal brazier of P, remove porcelain tube, metal parts and the adsorbed CO of electronics powder three
2, N
2, NH
3Deng waste gas and moisture content, constant temperature 20 minutes is closed the diffusion pump valve, stops the vacuum seal brazier is bled;
(2) open neon pipeline charging valve, let neon slowly charge in the vacuum seal brazier, when the precision pressure gauge indication reaches the median that calculates by setting, close neon pipeline charging valve;
(3) open argon gas pipeline charging valve, let argon gas slowly charge in the vacuum seal brazier, when the precision pressure gauge indication reaches setting, close argon gas pipeline charging valve;
(4) constant temperature heated up after 20 minutes, and the vacuum seal brazier is heated to 820~840 ℃, and constant temperature was cut off the electricity supply after 15 ± 2 minutes, took out ceramic gas discharge tube when naturally cooling to below 200 ℃, got into later process.
The present invention also provides a kind of aerating device of low pressure ceramic gas discharge tube; Comprise heating and vacuum seal system, the precision pressure gauge that is connected with said heating and vacuum seal system; Also comprise two charging valves that are arranged in parallel, the gas outlet of said two charging valves is connected with the inflation inlet of said heating and vacuum seal system respectively.
Said charging valve is a needle valve.The sealed vacuum number of degrees magnitude of said needle valve is 10
-6P.
The precision of said precision pressure gauge is 0.4 grade, and show value is-0.1~0MPa.
Useful technique effect of the present invention is:
The present invention charges into separately in the discharge tube of treating soldering and sealing in the vacuum seal body of heater by setting respectively with single gas of planting of two kinds of different electric ionization potentials, lets them autogamy mix.In the instrument indication range, the ratio of Ar in mist can fix or change forever with the need, in production and scientific research, has flexibility, the very high ceramic gas discharge tube of all kinds of specification qualification rates of more convenient manufacturing, and the expansion of its range of application has more prospect.Can find the fixed gas proportioning, the minimum disruptive voltage Vs value during different pressure P value; Minimum disruptive voltage Vs value in the time of also finding identical pressure P value, gas with various proportioning.Thereby find best low breakdown voltage Vs value, formed the complete process of spreading over a whole area from one point, adapt to the production requirement of all kinds of puncture voltage Vs.
Embodiment
Below in conjunction with accompanying drawing, the present invention is specified through embodiment.
Inflation method of the present invention be with two kinds of different electric ionization potentials single plant gas by molecular amounts than mixing in the burner hearth that charges into the vacuum seal brazier respectively; Mist gets into and places in the discharge tube of treating soldering and sealing of burner hearth, and electrode and the earthenware with discharge tube seals soldering and sealing at last.Preferably, single kind gas of these two kinds of different electric ionization potentials is neon and argon gas, and wherein the shared molecular amounts of argon gas is 1.0~2.5%, and surplus is a neon.
The concrete steps of above-mentioned inflation method are following: (1) is 1 * 10 with ceramic gas discharge tube to be processed in vacuum degree before inflation
-4P~5 * 10
-4Progressively be warming up to 720 ± 2 ℃ in the vacuum seal brazier of P, remove porcelain tube, metal parts and the adsorbed CO of electronics powder three
2, N
2, NH
3Deng waste gas and moisture content, constant temperature 20 minutes is closed the valve of the diffusion pump that is connected with the vacuum seal brazier, stops the vacuum seal brazier is bled; (2) open neon pipeline charging valve, let neon slowly charge in the vacuum seal brazier, when the precision pressure gauge indication reaches the median that calculates by setting, close neon pipeline charging valve; (3) open argon gas pipeline charging valve, let argon gas slowly charge in the vacuum seal brazier, when the precision pressure gauge indication reaches setting, close argon gas pipeline charging valve; (4) constant temperature heated up after 20 minutes, and the vacuum seal brazier is heated to 820~840 ℃, and constant temperature was cut off the electricity supply after 15 ± 2 minutes, took out ceramic gas discharge tube when naturally cooling to below 200 ℃, got into later process.
As shown in Figure 2; The present invention also provides the aerating device of the low pressure ceramic gas discharge tube of realizing said method; Comprise heating and vacuum seal system 1, the precision pressure gauge 2 that is connected with heating and vacuum seal system 1; Also comprise two charging valves that are arranged in parallel 3 and charging valve 3 ', charging valve 3 and charging valve 3 ' gas outlet be connected with the inflation inlet 4 of heating and vacuum seal system 1 respectively.In the course of processing, processed product 5 is stacked in processing on the heating and the pedestal 6 of vacuum seal system 1 bottom.In the present embodiment, charging valve 3 and charging valve 3 ' be commercially available high accuracy needle valve, its sealed vacuum number of degrees magnitude reaches 10
-6P; Said precision pressure gauge 2 is the commercial goods, and its precision is 0.4 grade, and show value is-0.1~0MPa; Heating and vacuum seal system 1 are the commercial goods, and the connected mode of above-mentioned each equipment is identical with working method and prior art.
The applicant's development test and production practices confirm that the molecular amounts of Ar gas accounts for the gas discharge tube that can obtain minimum Vs value at 1.0~2.5% o'clock in the Ar-Ne mist.Describe through embodiment below:
Embodiment 1:
The manufacturing of low pressure ceramic two utmost point gas discharge tubes (model is 2R55 Φ 5.5 * 6).Material is prepared as follows:
Fe-Ni-Co alloy electrode: D outer diameter=Φ 5.5, neck root diameter d=Φ 3.9, height overall H=2.8, the high H of neck
1=2.3;
Porcelain tube: D outer diameter=Φ 5.5, inner diameter d=Φ 4.0, and high H=4.95 draws 4 of carbon lines; Electronics powder model: K203.5, two interelectrode distances 0.35 (above-mentioned alloy electrode and porcelain tube are the commercial goods, and unit is millimeter).
Venting condition is: charge into the Ne-Ar gaseous mixture, wherein the shared molecular amounts of Ar is 1.9%, and precision pressure gauge indication pressure values is-0.078MPa.
Because the initial value of precision pressure gauge be-0.1MPa, therefore be calculated as follows out when only charging into Ne, the Ne force value that on precision pressure gauge 2, shows is :-0.078+ [0.1-(0.078)] * 1.9%, the force value that obtains is-0.0784MPa.
Gas replenishment process is following: above-mentioned alloy electrode and porcelain tube are carried out general assembly by prior art.The ceramic gas discharge tube that assembles 5 being stacked on the pedestal 6 of heating and vacuum seal system 1 bottom, is 5 * 10 at the sealed vacuum degree
-4Progressively be warming up to 720 ℃ in the vacuum seal brazier 1 of P, remove porcelain tube, metal electrode and the adsorbed CO of electronics powder
2, N
2, NH
3Deng waste gas and moisture content, constant temperature 20 minutes is closed diffusion pump valve (not shown), stops vacuum seal brazier 1 is bled.Open neon pipeline charging valve 3 ', let neon slowly charge in the vacuum seal brazier 1 through inflation inlet 4, when precision pressure gauge 2 indication reach-during 0.0784MPa, close neon pipeline charging valve 3 '.Open argon gas pipeline charging valve 3, let argon gas slowly charge in the vacuum seal brazier 1 through inflation inlet 4, when precision pressure gauge 2 indication reach-during 0.078MPa, close argon gas pipeline charging valve 3.Constant temperature heated up after 20 minutes, and the vacuum seal brazier is heated to 840 ℃, and constant temperature was cut off the electricity supply after 15 minutes, took out ceramic gas discharge tube when naturally cooling to below 200 ℃.The electronics powder that product is carried out the 1.5 second time of 1.2A alternating current activates ageing.Test then.
Produce 100 two utmost point discharge tube products by above-mentioned process,, do not find gas leakage and substandard product through conventional method leak detection; Appoint and to take out 14 conventional methods tests of warp and to write down its Vs value, the test data 1-1 that sees the following form: (V of unit)
Contrast test: adopt aerating device shown in Figure 1, be stored in the mixed inert gas in the steel cylinder after employing neon and the argon gas molecular amounts mixed by fixing 90:10 during inflation, inflation pressure is same as described above; For-0.078MPa; Sealing welding technique for extra is same as described above, and is promptly identical with processing step (1), (4) of aforementioned techniques scheme, produces 100 two utmost point discharge tube products by this process; Through conventional method leak detection, do not find gas leakage and substandard product; Appoint and to take out 14 conventional methods tests of warp and to write down its Vs value, the test data 1-2 that sees the following form: (V of unit)
Can know that from table 1-1 and table 1-2 contrast under the above embodiment of the present invention 1 inflation method, when the Ar molecular amounts was 1.9% in the control mist, the dc breakdown voltage Vs mean value of two utmost point discharge tubes obviously reduced, and has belonged to the ultralow pressure discharge tube.
Embodiment 2:
On the basis of embodiment 1, only changing the shared molecular amounts of Ar is 2.4%, and other process conditions are constant, produce.Appoint and take out 14 product tests and write down its Vs value, test data sees the following form: (V of unit)
Can know from last table, under the venting condition of embodiment 2, when the Ar molecular amounts accounts for 2.4% in the mist, can produce two very low utmost point discharge tubes of dc breakdown voltage Vs.
Embodiment 3:
On the basis of embodiment 2, only change the electronics powder and be numbered D18K, other conditions are constant, produce.Appoint and take out 14 product tests and write down its Vs value, test data sees the following form: (V of unit)
Can know from last table, change electronics powder kind, under same venting condition, still can produce two very low utmost point discharge tubes of dc breakdown voltage Vs though compare with embodiment 2.Therefore inflation method of the present invention does not receive the influence of electronics powder kind.
Embodiment 4:
On the basis of embodiment 1, only changing the shared molecular amounts of Ar is 1.0%, and other process conditions are constant, produce.Appoint and take out 14 product tests and write down its Vs value, test data sees the following form: (V of unit)
Can know from last table, under the venting condition of embodiment 4, when the Ar molecular amounts accounts for 1.0% in the mist, can produce two very low utmost point discharge tubes of dc breakdown voltage Vs.
The present invention is equally applicable to make low pressure ceramic three utmost point gas discharge tubes, also can effectively reduce puncture voltage Vs value.
Above-described only is preferred implementation of the present invention, the invention is not restricted to above embodiment.Be appreciated that those skilled in the art under the prerequisite that does not break away from spirit of the present invention and design, can make other improvement and variation.