CN105910676A - Magnetic field detection method for detection of key parameters of submerged arc furnace smelting - Google Patents
Magnetic field detection method for detection of key parameters of submerged arc furnace smelting Download PDFInfo
- Publication number
- CN105910676A CN105910676A CN201610228510.3A CN201610228510A CN105910676A CN 105910676 A CN105910676 A CN 105910676A CN 201610228510 A CN201610228510 A CN 201610228510A CN 105910676 A CN105910676 A CN 105910676A
- Authority
- CN
- China
- Prior art keywords
- point
- electrode
- magnetic induction
- magnetic field
- detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/003—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring position, not involving coordinate determination
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
Abstract
The invention relates a method for detection of key parameters such as an electrode end position, an arc length and a molten pool liquid level position in a production technology course of submerged arc furnace smelting and specifically relates to a new method for detection of the key parameters of the submerged arc furnace smelting, namely the magnetic field detection method. The magnetic field detection method comprises the steps that firstly, an internal circuit model of a submerged arc furnace is established; secondly, a magnetic field radiation model of the submerged arc furnace is established according to electromagnetic field theories, and two measurement origin points including (i)P(/i)1 and (i)P(/i)2 in the furnace are selected; and thirdly, the measurement origin point (i)P(/i)1 is taken as the origin point (i)O(/i), multiple points on the origin point axis (i)z(/i) are extracted as detection points, a magnetic induction intensity curve is obtained according to magnetic induction intensities at each detection point, and the molten pool liquid level position, the electrode end position and the arc length parameter can be obtained according to the magnetic induction intensity curve. The invention discloses the non-contact magnetic field detection method based on an electromagnetism theory for the first time. The detection theory is characterized in that a corresponding electromagnetic field model is established, so that the electrode end position, the arc length and the molten pool liquid level position in the submerged arc furnace can be determined effectively.
Description
Technical field
The present invention relates to the key parameter detection methods such as electrode tip position in mine heat furnace smelting production process, arc length and bath surface position, the new method magnetic field detection method of a kind of mine heat furnace smelting key parameter detection.
Background technology
Mineral hot furnace is to utilize arc discharge melting Ore, and therefrom extracts a kind of industrial furnace of useful metal, produces electric arc, and electrode is the critical component by carrying out arc smelting in powerful electric current importing stove between the electrode tip of electric furnace and furnace charge.In smelting process, by lifting electrode regulating furnace heat distribution and the degree of balance of three-phase molten bath power.
During mine heat furnace smelting, electrode tip position, arc length and bath surface position these three parameter are the most crucial, and domestic currently mainly depend on simple instrument and personal experience judges above key parameter indirectly, this is just difficult to ensure that smelting process parameter optimization, impact smelt the economic parameters such as energy consumption and ore deposit consumption.Mensuration for these key parameters, although existing many discussion and method, but these have plenty of calculating indirectly and speculate, and have the most only can record roughly electrode tip position, and is difficult to learn arc length and bath surface position.Up to now, all detections to above-mentioned key parameter are all not directed to by the method in magnetic field.
Summary of the invention
During the present invention is to solve mine heat furnace smelting, the problem that electrode tip position, arc length and bath surface position these three key parameter can not effectively measure, it is provided that the new method magnetic field detection method of a kind of mine heat furnace smelting key parameter detection.
The present invention adopts the following technical scheme that realization: the new method magnetic field detection method of a kind of mine heat furnace smelting key parameter detection, comprises the following steps:
The first step: set up mineral hot furnace internal circuit model, flowing through the electric current of electrode in stove is electrode current, electrode current in arrival molten bath, arc region, formation molten bath current loop at bath surface;
Second step: according to Theory of Electromagnetic Field, set up mineral hot furnace magnetic field radiation model, set electrode tip and be positioned on the perpendicular bisector of this plane as perpendicular bisector, P1 measurement initial point in selected stove, P1 measurement initial point at the perpendicular bisector of the projection join line being arbitrarily parallel in bath surface plane;
3rd step: with P1Measuring initial point is initial point O, takes S in the three-dimensional coordinate z-axis at initial point O place1、S2、…、Sm、…、SiIf doing as test point, then test point SiMagnetic induction component B at x, y, z axlexi、Byi、BziIt is shown below:In formula, hiFor test point SiHeight, unit is m, a for measuring point of origin P1To the distance of electrode tip projection join line, I is molten bath electric current, and unit is m, μ0For the pcrmeability of vacuum, unit is H/m, the magnetic induction of each test point prepare magnetic induction curve, can draw bath surface position, electrode tip position and arc length parameter according to the distribution of magnetic induction on magnetic induction curve.
The new method magnetic field detection method of above-mentioned a kind of mine heat furnace smelting key parameter detection, further comprising the steps of:
The central point of figure setting the formation of electrode centers point line is referred to as electrode wires with the line of electrode centers point, selected P2For measuring initial point, P2Measure initial point be positioned at above bath surface and be positioned on electrode wires extended line;
With P2Measuring initial point is initial point O ', takes S in the three-dimensional coordinate z-axis at initial point O ' place1、 …、Sn…、SjIf ... do as test point, hjFor test point SjHeight, test point SjMagnetic induction component B at x, y, z axlexj、Byj、BzjIt is shown below,In formula, b is for measuring point of origin P2To the distance of electrode centers point, unit be m, I ' be electrode current, the magnetic induction of each test point prepare magnetic induction curve, bath surface position, electrode tip position and arc length parameter can be drawn according to magnetic induction curve.
Patent of the present invention proposes a kind of contactless magnetic field based on electromagnetic principle detection method first, and this Cleaning Principle is by setting up corresponding electromagnetic field model, effectively judges electrode tip position in mineral hot furnace, arc length and bath surface position.
Accompanying drawing explanation
Fig. 1 is mineral hot furnace internal circuit illustraton of model.
Fig. 2 is mineral hot furnace magnetic field radiation illustraton of model.
Fig. 3 is mineral hot furnace top view.
Fig. 4 is test point P1The Magnetic Induction Density Distribution figure at place.
Fig. 5 is test point P2The Magnetic Induction Density Distribution figure at place.
Fig. 6 is that on-the-spot test takes a schematic diagram.
Fig. 7 is fieldtesting results figure.
Detailed description of the invention
In conjunction with accompanying drawing, the present invention is described in more detail.
The new method magnetic field detection method of a kind of mine heat furnace smelting key parameter detection, comprises the following steps:
The first step: in the burner hearth of mineral hot furnace, powerful electric current, in electrode enters stove, forms current loop at weld pool surface, sets up stove internal circuit model, as it is shown in figure 1, the electric current of electrode is electrode current I in flowing through stove as a example by delta current loopA、IB、IC, electrode current IA、IB、ICIn arrival molten bath, arc region, it is formed about triangle molten bath current loop, I at bath surfaceAC、ICB、IBAIt is respectively molten bath electric current.
According to Biot Savart law, arbitrary current elements on any current loopThe point at place is referred to as source point, needs calculated magnetic induction intensityPoint be referred to as site, then current elementsProduced magnetic induction is represented byIn formula,For the position vector of source point,For the position vector of site, μ0For the pcrmeability of vacuum, unit is H/m, according to formula (1), it is known that shown in magnetic induction such as formula (2) produced by carrying flow direct conducting wire electric current I,
Can determine that the electrode of mineral hot furnace is connected with the electric current of up to 10 Wan An trainings according to above-mentioned theory, even if there being the metallic shield effect of furnace wall, outside stove, the most necessarily having size of current and the Magnetic Field in direction in reflection stove.Therefore, electrode tip position, arc length and bath surface position these three key parameter can just be learnt by obtaining the distribution of these Magnetic Field.This is equivalent to make one " CT " to measure for mineral hot furnace, and the detection being mine heat furnace smelting key parameter introduces a kind of brand-new solution.
Second step: according to Theory of Electromagnetic Field, can set up mineral hot furnace magnetic field radiation model, as in figure 2 it is shown, set P in Fig. 21、P2It is respectively two and measures initial point, P1Measure initial point to be positioned on perpendicular bisector, P2Measure initial point and be positioned at above bath surface, IACFor being parallel to P1Measure the molten bath electric current of initial point place three-dimensional coordinate x-axis, ICFor being parallel to P2Measure the electrode current of initial point place three-dimensional coordinate z-axis.
Convenient for measuring, " electrode wires " and the concept of " perpendicular bisector " is defined at this, as shown in Figure 3, it is parallel in the plane of liquid level at any one, line one equilateral triangle of composition of three electrode tips projections, the stove heart is the center of triangle, and the stove heart is referred to as " electrode wires " with the line of electrode, and the perpendicular bisector on each limit of triangle is referred to as " perpendicular bisector ".P1Measure initial point to be positioned on the perpendicular bisector in face, place, P2Measure initial point to be positioned in electrode wires.
3rd step: set the measurement point of origin P in Fig. 21For initial point O, do S if taking in z-axis1、S2、…、Sm、…、SiAs test point, wherein, SmPoint is positioned at electric current IAC、ICB、IBAConstitute geometrical plane on, be i.e. positioned on bath surface and with measure point of origin P1Overlap.If only considering electric current IACThe impact in produced magnetic field, then electric current IACAt perpendicular bisector P1The Magnetic Induction Density Distribution at place is as shown in Figure 4.
From Fig. 4 and formula (2), test point SiMagnetic induction component B at x, y, z axlexi、Byi、BziAs shown in formula (3):In formula, hiFor test point SiHeight [m], a for measure point of origin P1To the distance [m] in triangle sideline, ByiFor odd function, BziFor even function, ByiZero point corresponding to BziPeak point, BziPeak point near corresponding to the current channel in molten bath district.Obviously, from perpendicular bisector a little at along z-axis coordinate survey, ByiWith BziContaining information such as bath surface positions.
4th step: set the measurement point of origin P in Fig. 22For initial point O ', do S if taking in z-axis1、…、Sn…、Sj... as test point, hjFor test point SjHeight.Only consider electric current ICProduced magnetic field, then electric current ICP in electrode wires2The Magnetic Induction Density Distribution at place is as shown in Figure 5.From Fig. 5 and formula (2), test point SjMagnetic induction component B at x, y, z axlexj、Byj、BzjAs shown in formula (4):In formula, b: test point P2To electric current ICThe distance [m] of path, can occur cross directional variations at the following current direction of liquid level, from formula (4), Bxj=0, then there is B on liquid levelxj≠ 0, Byj=Bzj=0.It follows that at P2Place also can obtain the key parameter such as liquid level or even electrode tip.
When being embodied as, according to this method, the ferro-silico-manganese mineral hot furnace (6300KVA) of Yinchuan Usiminas is carried out field test.According to aforesaid theory analysis, magnetic induction component B on perpendicular bisectoryjWith BzjDistribution contain B in the information such as liquid level position, and electrode wiresxjDistribution also contain the key messages such as liquid level.Through considering and many experiments, test point is selected between perpendicular bisector and electrode wires, and be angle theta ≈ 20 ° with electrode wires, and initial point is located at below the furnace bottom in place of furnace wall about 6m, test scope along z-axis upwards, and contains electrode end, as shown in Figure 6, in Fig. 6 from the beginning of initial point, sampling 15 points along z-axis with the step-length of 10cm, every some collection takes its meansigma methods 6 times.
Fieldtesting results as it is shown in fig. 7, owing to taking a little, ByComponent shows without obvious quantity of information so that h~VyCurvilinear characteristic change is the most inconspicuous, therefore at this only to h~VxCurve and h~VzCurve is analyzed.As seen from Figure 7:
(1) h < in the range of 80cm, output voltage VxRelatively low, show that this section is under electrode tip;And at h > scope of 100cm, output voltage VxHigher, show that this section has been on electrode tip.Can be seen that h~VxCurve and formula (4) have bigger dependency.
(2) h~VzCurve is bell-like, and its peak point position exactly reflects itself and the transverse current I in molten bathACIt is in same level position.
(3) by above two curves, can speculate: be positioned at a certain section in the range of the electric arc under electrode tip may be present in the 20cm shown in Fig. 7.
Set forth herein the new method magnetic field detection method that a kind of mine heat furnace smelting key parameter based on electromagnetic principle detects, can be drawn a conclusion:
(1) AC magnetic field produced by the electrode current in theoretical proof mineral hot furnace, molten bath electric current is necessarily reflected in outside body of heater.
(2) key messages such as electrode end, liquid level and arc length are contained along the Distribution of Magnetic Field of longitudinal direction in electrode wires and perpendicular bisector some place.
(3) the Distribution of Magnetic Field situation of field measurement and theoretical derivation have preferable dependency, it was demonstrated that the effectiveness of method in this paper.
Claims (2)
1. the magnetic field detection method for the detection of mine heat furnace smelting key parameter, it is characterised in that comprise the following steps:
The first step: set up mineral hot furnace internal circuit model, flowing through the electric current of electrode in stove is electrode current, electrode current in arrival molten bath, arc region, formation molten bath current loop at bath surface;
Second step: according to Theory of Electromagnetic Field, sets up mineral hot furnace magnetic field radiation model, sets the electrode tip perpendicular bisector in the projection join line being arbitrarily parallel in bath surface plane as perpendicular bisector, P in selected stove1Measure initial point, P1Measure initial point to be positioned on the perpendicular bisector of this plane;
3rd step: with P1Measuring initial point is initial point O, takes S in the three-dimensional coordinate z-axis at initial point O place1、S2、…、Sm、…、SiIf doing as test point, then test point SiMagnetic induction component B at x, y, z axlexi、Byi、BziIt is shown below:In formula, hiFor test point SiHeight, unit is m, a for measuring point of origin P1To the distance of electrode tip projection join line, I is molten bath electric current, and unit is m, μ0For the pcrmeability of vacuum, unit is H/m, the magnetic induction of each test point prepare magnetic induction curve, can draw bath surface position, electrode tip position and arc length parameter according to the distribution of magnetic induction on magnetic induction curve.
A kind of magnetic field detection method for the detection of mine heat furnace smelting key parameter, it is characterised in that further comprising the steps of:
The central point of figure setting the formation of electrode centers point line is referred to as electrode wires with the line of electrode centers point, selected P2Measure initial point, P2Measure initial point be positioned at above bath surface and be positioned on electrode wires extended line;
With P2Measuring initial point is initial point O ', takes S in the three-dimensional coordinate z-axis at initial point O ' place1、…、Sn…、SjIf ... do as test point, hjFor test point SjHeight, test point SjMagnetic induction component B at x, y, z axlexj、Byj、BzjIt is shown below,In formula, b is for measuring point of origin P2To the distance of electrode centers point, unit be m, I ' be electrode current, the magnetic induction of each test point prepare magnetic induction curve, bath surface position, electrode tip position and arc length parameter can be drawn according to magnetic induction curve.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201610228510.3A CN105910676B (en) | 2016-04-13 | 2016-04-13 | A kind of magnetic field detection method for the detection of mine heat furnace smelting key parameter |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201610228510.3A CN105910676B (en) | 2016-04-13 | 2016-04-13 | A kind of magnetic field detection method for the detection of mine heat furnace smelting key parameter |
Publications (2)
Publication Number | Publication Date |
---|---|
CN105910676A true CN105910676A (en) | 2016-08-31 |
CN105910676B CN105910676B (en) | 2019-04-05 |
Family
ID=56746780
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201610228510.3A Expired - Fee Related CN105910676B (en) | 2016-04-13 | 2016-04-13 | A kind of magnetic field detection method for the detection of mine heat furnace smelting key parameter |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN105910676B (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106679555A (en) * | 2017-02-09 | 2017-05-17 | 内蒙古鄂尔多斯电力冶金集团股份有限公司 | Device and method for measuring electrode position of ore heating furnace |
CN109489535A (en) * | 2018-12-28 | 2019-03-19 | 焦振宇 | Welding tip position monitoring apparatus and system |
CN112880537A (en) * | 2021-01-14 | 2021-06-01 | 东北大学 | Device and method for measuring arc space distribution in vacuum arc remelting process |
CN116358562A (en) * | 2023-05-31 | 2023-06-30 | 氧乐互动(天津)科技有限公司 | Disinfection operation track detection method, device, equipment and storage medium |
CN117213356A (en) * | 2023-11-09 | 2023-12-12 | 北京朗信智能科技有限公司 | Submerged arc furnace electrode position detection system and detection method |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102680856A (en) * | 2012-05-16 | 2012-09-19 | 上海电力学院 | Method for measuring zero sequence current of power transmission line based on magnetic sensor array |
CN103969497A (en) * | 2014-05-22 | 2014-08-06 | 营口东吉科技(集团)有限公司 | Method for measuring arc current of alternating-current electric-arc furnace |
US8884614B2 (en) * | 2011-10-31 | 2014-11-11 | General Electric Company | Eddy current array probe |
CN104390579A (en) * | 2014-11-18 | 2015-03-04 | 西安交通大学 | Magnetic sensor array-based welding spatial position detection system and method |
CN104486859A (en) * | 2014-12-19 | 2015-04-01 | 成都高威节能科技有限公司 | Method for automatically tracking liquid level track of melting bath at electrode working points of submerged arc furnace |
-
2016
- 2016-04-13 CN CN201610228510.3A patent/CN105910676B/en not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8884614B2 (en) * | 2011-10-31 | 2014-11-11 | General Electric Company | Eddy current array probe |
CN102680856A (en) * | 2012-05-16 | 2012-09-19 | 上海电力学院 | Method for measuring zero sequence current of power transmission line based on magnetic sensor array |
CN103969497A (en) * | 2014-05-22 | 2014-08-06 | 营口东吉科技(集团)有限公司 | Method for measuring arc current of alternating-current electric-arc furnace |
CN104390579A (en) * | 2014-11-18 | 2015-03-04 | 西安交通大学 | Magnetic sensor array-based welding spatial position detection system and method |
CN104486859A (en) * | 2014-12-19 | 2015-04-01 | 成都高威节能科技有限公司 | Method for automatically tracking liquid level track of melting bath at electrode working points of submerged arc furnace |
Non-Patent Citations (2)
Title |
---|
ARTHUR BLÜSCHKE: "一种用于检测金属物体轮廓和材料性能的新型传感器—涡流阵列", 《无损检测》 * |
吴俭民 等: "矿热炉电极工作长度监测系统的研究与实现", 《化工自动化及仪表》 * |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106679555A (en) * | 2017-02-09 | 2017-05-17 | 内蒙古鄂尔多斯电力冶金集团股份有限公司 | Device and method for measuring electrode position of ore heating furnace |
CN109489535A (en) * | 2018-12-28 | 2019-03-19 | 焦振宇 | Welding tip position monitoring apparatus and system |
CN112880537A (en) * | 2021-01-14 | 2021-06-01 | 东北大学 | Device and method for measuring arc space distribution in vacuum arc remelting process |
CN112880537B (en) * | 2021-01-14 | 2021-12-03 | 东北大学 | Device and method for measuring arc space distribution in vacuum arc remelting process |
CN116358562A (en) * | 2023-05-31 | 2023-06-30 | 氧乐互动(天津)科技有限公司 | Disinfection operation track detection method, device, equipment and storage medium |
CN117213356A (en) * | 2023-11-09 | 2023-12-12 | 北京朗信智能科技有限公司 | Submerged arc furnace electrode position detection system and detection method |
CN117213356B (en) * | 2023-11-09 | 2024-03-26 | 北京朗信智能科技有限公司 | Submerged arc furnace electrode position detection system and detection method |
Also Published As
Publication number | Publication date |
---|---|
CN105910676B (en) | 2019-04-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN105910676A (en) | Magnetic field detection method for detection of key parameters of submerged arc furnace smelting | |
US11096251B2 (en) | Calculation method for operating resistance in dual-electrode dc electric-smelting furnace for magnesium | |
CN105149738B (en) | Bidirectional magnetic control arc type welding seam tracking sensor | |
AU2020100496A4 (en) | A Very-Short Offset Transient Electromagnetic Method with a Grounded-wire Source | |
Wang et al. | 3D numerical simulation of electrical arc furnaces for the MgO production | |
CN106123756B (en) | A kind of contactless magnetic field array sensing detecting system and probe distance setting method | |
CN106679555A (en) | Device and method for measuring electrode position of ore heating furnace | |
CN205537769U (en) | Parameter detecting device is smelted to hot stove in ore deposit based on electromagnetism principle | |
CN106123768A (en) | A kind of electrodes in mine hot stove depth-measuring system | |
CN103969497A (en) | Method for measuring arc current of alternating-current electric-arc furnace | |
CN105698875A (en) | Apparatus for detecting smelting parameters of submerged-arc furnace based on electromagnetic principle | |
CN206523125U (en) | A kind of electrodes in mine hot stove position-measurement device | |
CN203980611U (en) | A kind of liquid heater | |
Zhang et al. | Technical Parameter Analysis of High-Frequency Induction Heating Applied to Steel Plate Bending. | |
Liu et al. | A non-contact detection method for smelting in submerged arc furnace based on magnetic field radiation | |
CN104486859B (en) | Electrodes in mine hot stove acting point is from the method for motion tracking bath surface track | |
Makarov et al. | Increasing the arc efficiency by the removal of arc electromagnetic blowing in electric arc furnaces: I. Effect of electromagnetic blowing and the slag height on the arc efficiency in an electric arc furnace | |
Kazem et al. | Design of Induction Coil for Oxygen Free Copper Production | |
Reynolds | The dual-electrode DC arc furnace-modelling brush arc conditions | |
WO2020003230A1 (en) | A detection system for detecting the level of metal in a melting furnace | |
CN201577215U (en) | Open submerged arc furnace electrode control system | |
Li et al. | Temperature field analysis and adaptive neuro-fuzzy inference system for mgo single crystal production | |
CN203324210U (en) | Gasoline oxidation stability measuring device | |
GB600034A (en) | Electrolytic production of aluminium | |
CN103510127B (en) | The device at molten aluminum liquid interface in real-time monitoring aluminium cell |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C06 | Publication | ||
PB01 | Publication | ||
C10 | Entry into substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20190405 Termination date: 20200413 |
|
CF01 | Termination of patent right due to non-payment of annual fee |