JB/T 5267-1991 Vacuum tube high frequency induction heating power supply device
Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB5267--91
Evacuum Tube High Frequency Induction Heating Power Supply Device 1991-06-28 Issued
The Ministry of Machinery and Electronics Industry of the People's Republic of China implemented on 1992-07-01
Mechanical Industry Standard of the People's Republic of China
Main Contents and Scope of Application of Vacuum Tube High Frequency Induction Heating Power Supply Device
JB5267-91
This standard specifies the requirements for vacuum tube high frequency induction heating power supply devices, including product classification, technical requirements, test methods, inspection rules, grade classification, marking, packaging, transportation, storage, ordering and supply, etc. This standard applies to vacuum tube high frequency induction heating power supply devices (hereinafter referred to as devices), which can be used as power supplies for high frequency induction heating equipment such as surface and local heating, heat penetration, melting and welding. 2 Reference standards
GB2900
GB10067.1
GB3797
GB3859
GB8702
GB10066.1
3 Terminology
Electrical terminology
Measurement method of output power of high-frequency induction heating power supply Basic technical conditions for electric heating equipment Part 1 General part Electric control equipment Part 2 Electric control equipment equipped with electronic devices Semiconductor power converter
Electromagnetic radiation protection regulations
Test methods for electric heating equipment
Part 1, General part
Except for the following supplementary provisions, the rest shall comply with the provisions of the corresponding chapters of GB2900 and the provisions of Chapter 3 of the national standard "Measurement method of output power of high-frequency induction heating power supply device".
3.1 Vacuum tube oscillator
A vacuum tube oscillator circuit that converts direct current into high-frequency current. 3.2 Total efficiency
The ratio of the device output power to the input power. 4 Product classification
4.1 Product use
The device can be divided into the following categories according to its use: surface and local heating floating fire (C), diathermy (T), melting (R), welding (H), vacuum heating (Z), plasma (D) and other products. 4.2 Working frequency
The device can be divided into four levels according to the working frequency range: 30~40kHz, 80~100kHz, 200~250kHz, 350450kHz. 4.3 Output power
The device is divided into 25 specifications according to the rated output power: 0.5, 1, 2, 3, 5, 7, 10, 15, 20, 25, 30, 40, 50, 60, 80, 100, 150.200, 250, 300, 400, 500, 600, 800, 1000kW. 4.4 Model
The model of the device consists of the following parts: GG-34--0
Approved by the Ministry of Machinery and Electronics Industry on June 28, 1991 and implemented on July 1, 1992
Among them; GG
JB5267-91
Series code of high-frequency induction heating power supply device: code for the purpose of the device;
Rated output power, in kW;
—operating frequency Code
0.3:30~40kHz
80~100kHz
200～250kHz
4; 350~450kHz
Dual frequency is represented by double code, and the codes are separated by "/\". The representation method of multi-frequency is similar. The national modification code is represented by letters AB, C...; the technical level code is represented by letters AB...; the enterprise code.
4. 5 Product model examples
Example 1 The rated output power of the device produced by the factory with the enterprise code WL is 60kW, the working frequency is 30~40kHz, 200~250kHz, the technical level is A, and the model of the device for surface and local heating quenching is: GGC60-0.3/2-A-WL
Example 2 The rated output power of the device produced by the factory with the enterprise code LPS is 200kW, the working frequency is 350~450kHz, it has been modified three times, the technical level is B, and the model of the device for welding is: GGH200-4C-B-LPS
4.6 Main parameters
The following items should be listed for each model of the device in the enterprise product standard: a.
Power supply voltage, V;
Power supply frequency, Hz;
Power supply phase number;
Rated input capacity, kVA
Rated output power, kW;
Working frequency, kHz;
Total efficiency, %;
Cooling water consumption, L/min;
Water pressure, Pa;
Weight, t
External dimensions, mm.
5 Technical requirements
5.1 General requirements
The device shall comply with the relevant provisions of Chapter 3 of GB3797 and Chapter 5 of GB10067.1. When there is a difference between the two standards, GB 3797 shall prevail. When there is a discrepancy between the provisions of the two standards and this standard, this standard shall prevail. 5.2 Supplementary requirements for design and manufacture
5.2.1 Overall design
5.2.1.1 The device is usually floor-standing. Devices with a rated output power of less than 5kW can also be desktop. 5.2.1.2: The device mainly consists of three parts: rectifier circuit, oscillator circuit and control circuit. 5.2.1.3 The components and devices installed in each part of the device shall comply with In accordance with the relevant provisions of Article 3.2 of Chapter 3 of GB3797. 2
JB.526791
For the electrical clearance and waist distance between various parts in the installation, for safety considerations, the design can refer to the requirements of Table 1
Peak voltage
≤250
>250~500
>500~1000
>1000~1500
>15 00~2000wwW.bzxz.Net
>2000~3000
>3000~6000
>600010000
>10000~15000
>15000~20000
>20000~30000
Electrical distance
Electrical distance
5.2.1.5 The device usually adopts three-phase 380V power supply. For the installation with rated output power less than 5kW, it is allowed to use single-phase 220V power supply. If there are different requirements, they can be put forward in Article 9.2. 5.2.1.6 The device should have undervoltage protection to prevent damage to the device due to undervoltage in any phase of the three-phase system. 5.2.1.7 Openings where operators can access components with working voltages above 50V (i.e., the second and third voltage bands) in the cabinet, as well as all cabinet doors and movable panels, shall be equipped with electrical interlock safety switches. Panels fastened with screws are an exception. Special requirements may be raised in Article 9.2.
All cabinets and chassis assemblies must have reliable grounding terminals. The device shall be provided with a grounding rod or an automatic grounding system. When a grounding rod is provided, the grounding point shall be marked: The installation location of the electrical components in the device shall avoid the influence of water leakage or "condensation" that may be caused by the water cooling system. 5.2.1.11\: In addition to complying with the requirements of Article 3.7 of GB3797., the insulation resistance and dielectric test of the device shall not be less than the product of 1ka/V: and the rated voltage of the line, between each conductor of the high-voltage line and the machine light, between the high-voltage line and the control line, and between the control line and the housing.
5.2.1.12 The noise generated by the device during normal operation shall comply with the provisions of Article 3.4 of GB3797. 5.2.1.13
When the device is working under the specified conditions, its parts and components shall not be overloaded. However, the instantaneous overload with protection is excluded. 5.2.1.14.: Class A devices should be equipped with multi-tap filament power transformers and anode high-voltage rectifier transformers, and Class B and C devices should be equipped with filament power regulators, anode high-voltage rectifier transformers and anode voltage regulating devices. 5.2.1.15 The device should adopt power supply filters and other appropriate measures to minimize the radio interference to the power grid and other equipment generated during the operation of the device.
5.2.2 Rectification circuit
The silicon rectifier power supply in the device should comply with the relevant provisions of GB3859. 5.2.2.1
5.2.2.2 Each phase of the high-voltage rectifier transformer should be connected in parallel with a surge suppressor to prevent surge voltage from damaging the device. 5.2.2:3 When the rectifier power supply uses capacitor filtering, a scavenger resistor must be added to its output circuit. 5.2.3 Oscillation circuit
5.2.3.1 It should be equipped with an adjustable slot circuit element with a large enough adjustment range to adapt to different loads and can quickly adjust to the required operating frequency and induction heating conditions within a large range of changes. 5.2.3.2 If necessary, it should also be equipped with a corresponding high-frequency output transformer with adjustable turns ratio so that the load can be matched to the optimal value. 3
5.2.4 Control and protection circuit
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5.2.4.1 The device should be equipped with main circuit breaker, anode power contactor, variable gate excitation control, anode overload reset control and high-frequency output power control.
5.2.4.2 The device should be equipped with a delay mechanism. Ensure that the oscillator tube has sufficient preheating time before the high-voltage rectifier voltage is applied to the anode of the oscillator tube. 5.2.4.3 The device should have a stepless power regulation controller. A and B grade products adopt manual control mode, and C grade products adopt automatic control mode, and should be able to accept standard DC input signals from temperature controllers, with values of 0~5 or 4~9mA, or 0~10V. 5.2.4.4 Unless otherwise required (see Article 9.2.), the rate exergy device should also be equipped with a timing controller with a scale of 1s per minute and a repeatability accuracy of ±0.25%.
5.2.4.5 Except for the main circuit breaker, all operating mechanisms should be installed in the front of the cabinet where they are easy to operate. 5.2.4.6 If the purchaser requires a foot-operated "on-off" switch to control the output power (see Article 9.2), it can be negotiated with the supplier. 5.2.5 Cabinet and structure
5.2.5.1' The design of the device cabinet should take into account the minimization of the high-frequency radiation leaked. The intensity of the stray electromagnetic field in the operator's workplace should comply with the provisions of GB8702.
5.2.5.2 The steel fasteners used in the device should have an anti-corrosion layer. 5.2.5.3. If the purchaser requires a fully enclosed self-cooling cabinet (see Article 9.2), it can be negotiated with the supplier. 5.2.6 Heating table (screen)
Each unit should generally be equipped with a heating table (screen), and the high-frequency output terminal should be located in front of the heating table (screen) so that the load coil can be easily loaded, unloaded, replaced and reliably connected. 5.2.7 Cooling system
The device should be equipped with a water cooling system or an air cooling system with a filter. 5.2.7.1 The water cooling system should meet the corresponding requirements of Article 5.1.3 of GB10067.1. 5.2.7.2 The conductivity of the cooling water should not be greater than 50μs/cm. 5.2:7.3' The design of the water cooling system should be able to avoid the phenomenon of "condensation". 5.2.7.4 When the maximum inlet water temperature is 35℃, the water flow rate shall be sufficient to ensure that the outlet water temperature of each branch of the open-circuit cooling system does not exceed 55℃, and the outlet water temperature of each branch of the closed-circuit cooling system does not exceed 65℃. 5.2.7.5 When the purchaser requires a closed water cooling system equipped with a heat exchanger (see Article 9.2), it can be agreed with the supplier when placing an order. 5.2.7.6 The device shall be equipped with a temperature relay so that it can give an advance alarm before the water temperature exceeds the specified safety upper limit, and can cut off the power supply of the oscillating tube anode in time when it exceeds the upper limit.
5.2.7.7 The device shall be equipped with a differential water pressure or water flow relay to ensure that the device stops working when the water flow is interrupted or the water supply to the relevant components of the device is insufficient.
5.2.7.8. The air cooling system shall maintain a positive pressure in the cabinet, except for the fully enclosed self-cooling system. 5.2.7.9 The device equipped with an air cooling system shall be equipped with an ambient temperature upper limit relay and an air flow relay. When the airflow intensity approaches or exceeds the upper limit of the allowable operating temperature, it should be able to give an early alarm and cut off the filament power supply and anode power supply of the oscillating tube in time. 5.2.8 Meter only
5.2.8.1 The installation should be equipped with indicating instruments for indicating the filament voltage, DC anode voltage, anode current, and grid current of the oscillating tube. The accuracy level of the DC instrument should not be lower than Class 1.5, and the accuracy level of the AC instrument should not be lower than Class 2.5. 5.2.8.2 All instruments should be set in the position on the cabinet that is easy for the operator to observe. 5.2.9 Electrical assembly
5.2.9.1 The electrical assembly of the device should comply with the requirements of the design drawings and relevant technical documents. All purchased electrical components and accessories must be retested and accepted by the inspection department before use.
5.2.9.2 The assembly of control units such as printed circuit boards, plug-ins, drawers and small boxes shall not have the phenomenon of desoldering, cold soldering and loose fasteners, and shall be able to withstand high temperature and high and low temperature cycle tests after assembly. 5.3 Performance requirements
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JB5267-91
5.3.1 Under normal working conditions, the device should be able to provide normal power supply for induction heating of conductive materials such as ferrous metals and non-ferrous metals within the specified frequency limit and output power.
5.3.2 The output power of the device should not be less than the rated value of the device. 5.3.3
The operating frequency of the device should comply with the frequency range specified in this standard. When the device is running at full load, its power factor should not be less than 0.86. 5.3.4
5.3.5 The total efficiency of the device should not be less than 45% for Class A products, 55% for Class B products, and 65% for Class C products. The filament voltage of the oscillator tube and its deviation should comply with the provisions of the enterprise product standards. When the grid voltage fluctuates by ±10%, the filament voltage 5.3.6
The fluctuation should not be greater than ±2%.
5.3.7B and C grade products should be equipped with a device to adjust the power supply voltage or the anode voltage of the oscillator tube. When the grid voltage fluctuates by ±10%, the fluctuation range of the anode DC high voltage should not exceed ±2% for B grade products and should not exceed ±1% for C grade products. 5.3.8 Devices above 3kW should be equipped with a positive current overcurrent protection link, and devices above 10kW should also be equipped with a grid current overcurrent protection link. When the output current exceeds the set current value, the overcurrent protection link should immediately operate, causing the device to automatically stop working and issue an overcurrent indication signal. 5.3.9
After the device runs continuously at rated output power until the temperature rise stabilizes, the maximum temperature rise of each component and part should comply with the provisions of Table 2. Table 2
Parts in the device
Busbars for connecting low-voltage electrical appliances
Busbars for connecting semiconductor devices
Busbars for high-voltage contacts
Circuit enclosure
Transformer core
Resistor elements
Material and working conditions of vacuum tubes, semiconductor devices and other components
Copper
Tin-plated or saw-plated copper
Silver-plated copper
Copper
Tin-plated or cadmium-plated copper
|Silver-plated purple steel
Purple copper
Circular surface of wire during natural cooling
Class A insulation
Class E insulation
Class B insulation
Air at a horizontal distance of not less than 30mm
Glazed surface
Outer surface
Limiting temperature rise K
Meet the respective standards of components
5.3.10 The device should be able to withstand three consecutive high-voltage on-off tests under rated power output without abnormal phenomena. 5.4 Reliability requirements
5.4.1 The average trouble-free working time of the device under normal use and maintenance conditions shall be not less than 1000, 2000, and 3000h for A, B, and C grade products, respectively, except for smelting equipment. 5.4.2 The industrial operation test of smelting equipment shall be carried out for at least 100 heats without abnormal banding. 5.4.3 The average service life of the device shall not be less than 10 years. 5.5 Requirements for complete sets
The scope of complete sets of devices specified by the supplier shall be listed in the enterprise product standards. Generally, the following items shall be included: 5.5.1
The high-frequency power supply device includes a vacuum tube oscillator, a high-voltage rectifier, a power supply control cabinet (set) and a power supply filter, etc.: connecting wires, cables, and output feeders between cabinets; 5
c. Spare parts;
JB5267-91
d, product manual, including necessary drawings. The specific contents of the above items shall be listed in the enterprise product standards, including models, specifications and quantities. If the purchaser does not need certain supply items specified by the supplier, it shall be proposed in accordance with Article 9.2. 5.5.2 When the following accessories or loading quantities are required, they can be proposed in accordance with Article 9.2. a.
Temperature controller, temperature recorder:
Voltage adjustment device;
Foot-operated "on-off" switch;
Program controller with microcomputer;
Heat exchange device of closed water cooling system:
Inductor or furnace and high-frequency output transformer. 6 Test method
The test method of loading shall be carried out in accordance with the relevant provisions in GB10066.1 and GB3797 and the following supplementary provisions. When there are differences in the provisions of the three standards, this standard shall prevail. 6.1 Test conditions
The test environment conditions, power supply voltage and measuring instruments of the device shall be in accordance with the provisions of GB10066.1.4.3, 4.4, 4.5. 6.2 Test methods
6.2.1 Appearance inspection
According to Article 4.2 of GB3797.
6.2.2 Safety inspection
According to Article 7.1.2 of GB10066.1.
6.2.3 Durability test of label writing
According to Article 7.1.3 of GB10066.1.
6.2.4 Insulation resistance inspection and dielectric test
According to Articles 4.3 and 4.4 of GB3797.
6.2.5 Overcurrent protection test
Set the overcurrent link setting value, change the output load of the device, make the positive current or gate current flow, and the protection link will be activated. At this time, the device should stop working and send out an overcurrent signal. This test should be repeated three times. 6.2.6 Water pressure underpressure or air flow underflow protection test Set the setting value of the water pressure or air flow relay, artificially reduce the water flow or air flow to a certain value to make the relay operate, at this time the device should stop working and send out an undervoltage or underflow signal. This test should be repeated three times. 6.2.7 Electromechanical interlocking test
Disrupt the start and stop operation sequence, perform three wrong operation actions, and there should be no phenomenon that endangers personal safety and damages parts and components.
6.2.8 Temperature rise test
Make the device run continuously at rated output power until the temperature rise is stable (cabinet temperature change is less than 1℃/h), use a surface thermoelectric thermometer or other temperature measuring instrument with an accuracy of not less than 2.5 to directly measure the temperature of the outer surface of the cabinet, the temperature of the cooling water inlet and outlet, and the temperature rise of the rest of the device should be measured immediately after the cabinet door is opened after the power is turned off. 6.2.9 High and low temperature cycle test
According to Article 4.11 of GB3797.
6.2.10 High temperature storage test
According to Article 4.12 of GB3797.
6:2.11 Load test and measurement of main technical parameters JB5267-91
According to the national standard "Measurement method of output power of high-frequency induction heating power supply", select appropriate measurement methods and corresponding equivalent loads to make the device work at the rated output power. For type inspection, it should run continuously for 8 hours. For factory inspection, the first unit of each batch should run continuously for 4 hours, and the remaining units should run continuously for at least 2 hours. After the temperature rise is stable, record the following data: oscillating tube filament voltage U., V;
anode DC voltage E,, kV,
anode DC current I., A;
gate DC current I. , A;
Trough circuit high frequency voltage U, kV;
Oscillating tube anode cooling water flow Q,, L/min; Oscillating tube anode cooling water outlet temperature T,, ℃ before high pressure; Oscillating tube anode cooling water outlet temperature T,, ℃ during heating; Equivalent load calorimeter water flow Q,, L/min; Equivalent load calorimeter water inlet temperature T., C; Equivalent load calorimeter water outlet temperature T., ℃; Power supply input current I~, A:
Power supply input voltage U_, V
Power supply power factor cosg1
Thus, the power and efficiency of the device are obtained according to the following calculation formula. 0.
Power input power
P,=3.U_.1~cosP10~*
Oscillator tube anode DC input power
Po-E..I..
Oscillator tube anode loss power
P=0.07QT-T）
Oscillator power
s.High frequency output power
PHe=0.07Q
·（TT）
t.Vacuum tube oscillation efficiency
u.Total efficiency of the load
6.2.12Measurement of the output working frequency of the device PHE
Measured with an electronic counting frequency meter under load. 6.2.13Power supply interference test
According to Article 4.14.1 of GB3797.
6.2.14 Measurement of electromagnetic field strength of high-frequency stray radiation. 100%
Measured with an electromagnetic field strength tester at a distance of 1m from the device panel or high-frequency radiation source and 1.5m from the ground. 6.2.15 Noise measurement
According to Article 4.16 of GB3797.
6.2.16 Electric shock test
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The device is subjected to three cyclic electric shock tests at rated output power with an interval of 1min, in which the anode power supply of the oscillation circuit is suddenly shut down and opened. At this time, the oscillator and high-voltage rectifier should work stably without spark discharge and other abnormal band phenomena. 6.2.17 Transportation test
When necessary, according to Article 4.18 of GB3797. 6.2.18 Industrial operation inspection
The industrial operation of smelting equipment and the mean trouble-free working time and mean service life test of other purpose equipment shall be carried out under normal working conditions of the equipment, with the method of recording and providing data by the purchaser. If it is necessary to conduct the inspection in other ways, it can be proposed in Article 9.2. 7 Inspection rules and classification
The inspection rules and classification of the equipment shall be carried out in accordance with Chapter 7 of GB10067.1 and the following supplementary provisions. During the inspection, the equipment shall work stably, and no abnormal phenomena such as sparking and discharge are allowed (overload tripping caused by non-fault reasons such as sudden change of power supply voltage shall be able to be immediately re-closed to restore normal operation).
7.1 The factory inspection items of the device are as follows: a.
Appearance inspection;
Safety inspection;
Durability test of label writing;
Insulation resistance test;
Inspection of accessories, including inspection of model, specification and factory acceptance certificate; dielectric test;
Overcurrent protection test;
Water pressure undervoltage or air flow undercurrent protection test; electromechanical interlocking test;
'Temperature rise test;
High and low temperature cycle test;
High temperature storage test;
Load test and measurement of main technical parameters; measurement of device output operating frequency;
Electric shock test;
Scope of supply, including inspection of completeness of factory technical documents; Packing inspection.
7.2: The type inspection items of the device are as follows: a.
All factory inspection items (under type test conditions); power supply interference test;
Measurement of high-frequency stray radiation electromagnetic field strength; noise measurement.
7.3 Industrial operation inspection
When required (see Article 9.2), the device should be subject to industrial operation inspection. 7.4 If the purchaser has special requirements for inspection (see Article 9.2), it can be negotiated with the supplier when placing an order. 7.5 The technical classification of the device shall be as specified in Table 3. Devices of each technical level shall fully meet the requirements listed in the table and other provisions of this standard.
Technical level
Filament voltage and anode voltage regulating device
Stepless power regulation mode
Total efficiency
Anode voltage fluctuation range
Reliability
Completeness
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Can provide complete equipment according to the requirements of Article 5.5.1.
According to the requirements of Article 5.2.1.14
According to the requirements of Article 5.2.4.3
According to the requirements of Article 5.3.5
According to the requirements of Article 5.3.7
According to the requirements of Article 5.4.1
Can provide complete equipment according to the requirements of a, b, c in Articles 5.5.1 and 5.
2.2.
National-grade superior products of the device shall technically meet the requirements of the above C-level. 7.6
Marking, packaging, transportation and storage
Can meet all the requirements of 5.5.1 and 5.5.2
The marking, packaging, transportation and storage of the complete set of
devices shall comply with the provisions of Chapter 8 of GB10067.1 and the following supplementary provisions. 8.1
Unless otherwise required (see Article 9.2), the nameplate of the device shall indicate the following items: a.
Product model and name;
Input power parameters (number of phases, frequency, Hz and voltage, V); operating frequency, kHz;
Rated output power, kW;
Weight, kg
Product number:
Date of manufacture;
Name of manufacturer (country name shall be indicated for export products). h.
8.2 For the matching parts made by the manufacturer, the main parts, components and whole parts should have their own nameplates, and the content can refer to the provisions of Article 8.1. For small parts, it is allowed to design a simplified small nameplate, which should contain the registered trademark, product code and product number. 8.3 Large vacuum tubes, vacuum capacitors and other valuable and fragile components should use the original packaging boxes. 8.4 During transportation, the device should be protected from rain and snow, and should be placed gently without severe impact and vibration. The speed of the car on the intermediate road of the third-level highway should not exceed 25km/h. 8.5 Vacuum tubes, vacuum capacitors and other valuable and vulnerable components and instruments must be stored in a warehouse with a temperature below 1040℃ and above -30℃, with no drastic temperature changes, good ventilation, no corrosive gas and no obvious vibration. Ordering and Supply
9.1 The ordering and supply of the device shall be in accordance with the provisions of Chapter 9 of GB10067.1. 9.2 The purchaser may make the following requirements to the supplier. Different requirements for unit system, power supply voltage, power supply frequency, etc. (see Article 5.1.1.1 of GB10067.1 and Article 5.2.1.5a.
of this standard);
Different requirements for the use environment (see Article 5.1.2 of GB10067.1 and Article -3.1 of GB3797); e.
Additional requirements for safety and environmental protection (see Article 5.1.5.1 of GB10067.1 and Article 5.2.1.7 of this standard); Different requirements for painting (see Article 5.2.7 of GB10067.1); Special requirements for timing controllers (see Article 5.2.4.4); Requirement to provide control output power Foot-operated "on-off" switch (see Article 5.2.4.6); requiring the provision of a fully enclosed self-cooling cabinet (see Article 5.2.5.3); h.
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requiring the provision of a closed water cooling system equipped with a heat exchanger (see Article 5.2.7.5); different requirements for complete set supply items (see Article 5.5); different requirements for industrial operation inspection (see Article 6.2.18); requiring industrial operation inspection (see Article 7.3); special requirements for inspection (see Article 7.4); different requirements for nameplates (see Article 8.1): special requirements for packaging (see Article 8.2.5 of GB10067.1). The supplier should try its best to meet the special requirements of the demander, but the special requirements that can actually be selected by the demander shall be determined by the supplier according to their own conditions with reference to this standard. Some of them can be listed in the enterprise product standards, and the rest shall be agreed upon by both parties. Additional Notes:
This standard was proposed and managed by the National Technical Committee for Standardization of Industrial Electric Heating Equipment. This standard was drafted by Liaoning Electronic Equipment Factory and Xi'an Electric Furnace Research Institute. The main drafters of this standard are Zhong Ruizhang, Liu Xizang and Li Jingfang. 10
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