12T 8000KW medium frequency Induction Furnace

12T medium frequency steel shell induction melting furnace technical specification and complete set range

1）Technical program and specification

This program is recommended that whole set equipment of the furnace shall be equipped with two furnace bodies user can be readjusted by practical needs.

1.1 Technical program

The main equipment of this program is included 2SET of 4000KW(1set 8000KW) rectification transformer, 4 Low voltage control cabinet, 4 MF power supply cabinet, 2sets 12t MF induction furnace, 1 hydraulic station, 1 cooling water device, and other auxiliary device. The electric system diagram is as follows： 

 

 

 

 

 

 

 

 

 

 

 

 

The output of MF power supply is changed by manual operation, for the purpose of maintenance and alternative melting.

 

1.2 技术参数 （Technical parameter）

名    称		单位	参数	备注
额定容量Rated capacity		t	12
最大装载量Max load capacity		t	15
额定功率Rated power		kw	8000
工作频率Working frequency		Hz	250
熔化率Melting rate		t/h	10-12	1600℃
电耗Power consumption		kw.h/t	540-590	1600℃
感应炉感应器内径 Inductor inner diameter		mm	Φ1600
感应炉感应器高度 height of inductor		mm	2260
额定出钢水温度 Rated temperature of the melting steel		℃	1600
中频电源十二相进线电压 Incoming voltage of MF cabinet		v	950-1000
电源整流模式 electric rectificate mode			24脉
感应器电压Voltage of inductor		V	3200~3400	倍压Double voltage
炉 用 冷 却 水 Cooling water of the furnace	供水压力 pressure of incoming water	Mpa	0.25~0.3
	进水温度 temperature of incoming water	℃	≤5~35
	出水温度 temperature of the outlet water	℃	≤55
	流量（炉体） flow rate ( furnace body )	t/h	180	单台炉体 single furnace
	电源循环冷却水流量 flow rate (power source)	t/h	120
	电源循环冷却水温升 water temperature rise of power source	℃	10
电气冷却供水压力 cooling water pressure for power source		M pa	0.1~0.2
液 压 系 统Hydraulic system	工作压力 working pressure	M pa	12	双机双泵 Double motor, double pump
	流量 flow rate	L/min	160
	液压介质 hydraulic medium		抗磨液压油 Antiwear  hydraulic oil	夏季：N68 summer:N68 冬季：N46 winter:N46
	液压油缸缸径 diameter of the hydraulic cylinder	mm	Φ250
变 压 器 transformer	变压器容量 capacity of the transformer	KVA	5000×2台	（参考）
	变压器一次电压 incoming voltage	KV	10或35
	变压器二次电压 secondary voltage	V	950-1000
	接线方式Connection		网侧移相 Dy11d0 +7.5° Dy11d0 Net lateral phase +7.5	二侧Δ/Y双绕 2 Side Δ / Y pairs around the
			网侧移相 Dy1d2 -7.5° Dy1d2 Net lateral phase -7.5°	星型绕组中点引出 The mid-point star-shaped winding leads
	阻抗电压 Impedance voltage		8～9%
	调压方式Voltage mode		无励磁调压 No excitation voltage
	冷却方式Cooling		强油水冷却 Strong oil and water cooling

 

 

 

2）Products standard and operating conditions

2.1Products standard：

GB10067.3-88  ‘Basic specifications for electroheat installations—Induction electroheat installations’

GB10067.1-88  ‘Basic specifications for electroheat installations—General’

GB10066.3-88  ‘Test methods for electroheat installations—Induction crucible furnace’

GB5959.1-88  ‘Safety in electroheat installations—General requirement’

GB5959.3-88  ‘Safety in electroheat installations—Particular requirements for induction and conduction heating installations and induction melting installations’

GB／T4280-93  ‘Medium frequency coreless induction furnace’

GB／T8669-1997  ‘Semiconductor frequency conversion devices for medium frequency induction heating’

2.2 Operating conditions

2.2.1 Cooling water conditions

  PH：7－8.5

 Hardness：＜10degrees（Each degree that 1Lwater contains less than 10mg calcium oxide）

  Total solid content：＜250mg／L

 Water resistance：（Power）＞100KΩ－cm

               （Furnace）＞2KΩ－cm

2.2.2 Power supply conditions

a.       Three-phase voltage unbalanced  ＜5％

b.       Voltage fluctuations  ＜±5％

c.       Voltage waveform distortion factor  ＜10％

2.2.3 Geographical environment

a. Altitude above sea level  ＜1000m

b. Temperature 5~40℃

c. Relative humidity  ＜90％（20℃）

d.       No conductive dust, explosive gas and corrosive gas around the equipment.

e.       Avoid strong shake and concussion.

 

3）Electrical Technique Instruction

Electrical parts of the equipment include rectification transformer, low-voltage switch cabinet, medium frequency power cabinet, filter reactor, and compensation capacitor bank and water tank.

3.1 Rectifying transformer

This equipment uses special-purpose rectification transformer, which transforms 35KV or 10KV high voltage of the electrical network to 950V, which is suitable for the solid state power.

There is a no- load manual changer at the high voltage side of transformer, output voltage can be adjusted at －5%,0,＋5%. It is used to suit the deviation of grid. In order to ensure the safety of silicon-controlled rectifier and avoid to impact on the grid, this transformer request the big short circuit resistance value 10%, simultaneously adds the shielding layer between the primary and secondary-coils. There are a gas relay and the oil thermometer on the power transformer, its output is interlock with high-voltage switch cabinet, when there appears the gas alarm or higher oil temperature, it will automatically turn off the power.

Cooling of the Transformer uses the oil-filled self-cooling.

3.2 Low-voltage switch cabinet

   The low voltage switch-automatic air circuit breaker(DW15—1000V) is installed between the transformer output and the medium frequency power input, it is used in the make-and-break and isolates the overhaul of power source for maintenance.

   The air circuit breaker has fast broken for overload protection and the no voltage release protection.

  

3.3 Medium frequency power source

Controllable medium frequency power supply is AC—DC—AC equipment. It uses silicon-controlled rectifier to change there-phase DC to single-phase AC. The equipment is strongly adoptive to any load, and is widely used in metal melting, heat treatment, and crystal’s growth. The medium frequency source made by our company has some special feature list below:

1 、The cabinet uses GGD type cabinet structure, the arrangement of element is in one side, which is easy to install and maintain, the way of refrigeration is water-cooling or wind-cooling.

2 、Rectifying Bridge (KP tube), Inversion Bridge (KK tube), Silicon-controlled rectifier; those elements are all made by famous companies, the main components of control circuits are import, that guarantee its stability and reliability.

3、The device is started by frequency-sweep zero-voltage soft start mode for separately-excited to self-excited, in the whole startup process, at any moment the loads change is traked by the frequency adjustor system, circuit and voltage adjustment closed loop system, which leads to the perfect soft start-up. This way has less effect to controlled silicon and it extends its life. Also, it has characteristics advantage such as both light, and heavy load easily start up.

4、The electric circuit uses our patent constant-power controlled circuit. In the working process, it will watch the change of voltage and current by itself, and base on that to determine the change of load, automatically adjust the power output that let the equipment always has the largest power output. Especially for melting, this constant–power control can realize power output as larger as possible. It improves melting speed efficiently.

5、No need for special surveillance. The equipment only has one power switch and a power adjustment knob. It is easily to be operated. After start, you only need to turn the power to the largest position; others will work automatically. When increase large number of material, the equipment can adjust the power itself. It won’t stop suddenly as a result of over current and over voltage.

6、As the melting is fast and the thermal efficiency is high, once output is improved. It always works under the highest volts dc (rectifying α=0). The average output power can increase 12-20%. The melting cycle can decrease to 2/3 of primary one. Electric power can be saved over 10%.

7、The protective circuit is perfect, which let SCR parts always work under the safe range, and failure rate lower.

8、The device uses digital control circuit. It has high reliability. In the working process, three-phase current is balance. As the advantage in design, the sequence of three-phase power can be connected in any way, and the connection with capacitor cabinet or furnace body can’t distinguish phase angle, which made it the equipment can decide automatically and adaptive control. It is easy for installation and maintenance.

The line is used in AC—DC—AC parallel model; its system diagram is as follows：

Principle of main electric circuit

The 3-phase 50HZ AC is input to rectifying bridge through the fusible cut-out and breaker by its main circuit, which is changed to adjustable pulsating DC, after filtering by reactor it becomes smoothing A•C to be input to single phase inversion bridge, after inversion it becomes single phase alternating current (AC), and then the single phase AC source is input to load. The load circuit uses parallel connect oscillating circuit, this kind of inversion bridge is very adaptable for the load, and to be reliability and stability.

Except that the control system has fine protection system, in other parts of main electrical circuit there also have some protective component , each SCR has a RC absorption circuit, in can absorb the over voltage which comes out when element phase changing. To avoid damage element from short circuit and overload, to link a fast fusible cut-out at the input side of rectifying bridge.

Ⅱ Introduction of control circuit

BSC14M—2 constant power SCR frequency changing source control triggering panel includes power supply、adjuster、phase changing control、protection circuit、phase-rotation adaptive circuit、startup calculation circuit、inversion frequency tracking、inversion impulse form, pulse blow-up and pulse transformer. This core part used special large ASIC—2 Microprocessor circuit, caused the control circuit to realize the digitization, which has good capability, high consistence and it is made in US. All the inside circuit are digital, except adjustor, rectifier trigger doesn’t need any adjustment; it has high reliability, good impulse symmetry, strong anti-interference ability and fast reaction, also because it has phase-rotation adaptive circuit, do not need synchronic transformer. So during the debugging, there is no need to adjust the phase-rotation and check the synchronization, only need is to connect KP SCR gate line to the control panel, then the rectifier can work.

   Inversion circuit, we use frequency-sweep zero voltage startup, its function is better than normal one’s circuit, and it has automatic restart circuit that can avoid frequency changing source fails to start accidentally, so the successful start up rate is 98%. Frequency tracking circuit uses sampling average value, it improves the ability of anti-interference and it only needs sampling signal of frequency changing voltage, no need for the signal of slot capacitor’s current, so that you don’t need for extra frequency changing current’s phase-rotation, so during debugging and use, it won’t fail to start up, even if phase-rotation of frequency changing output line or sampling current indictor is reversed.

  There’s an inversion angle adjustment circuit in inversion circuit, which can automatically adjust matching of load impedance to achieve constant power output, and can be made for “fast smelting” frequency changing source, to achieve time saving and electricity saving, aims to improve power factor of network side (this function can also be turned off). The main circuit of inversion is inside part of ASIC—2 integrate circuit, and also is digital.

A、BSC14M—2 control panel include 12 integrate circuit, 12 transistors, 7 trimmer potentiometers, 47 lead-in terminals, it is easy for installation.

B、Model description

   B SC 14 M－2

                  

 

 

                Design serial number

                   Pulse transformer

               14 –ways pulse output

           Digital trigger pulse circuit

                 Closed loop control

 

Ⅲ Main technical parameter of main control panel

⑴ Lead-in rated voltage:100V~950V（50HZ）（Notice:R3、R7、R11DE matching）.

⑵ Control power supply: Single-phase 17V/2A.

⑶ Feedback signal of frequency changing voltage: AC 12V/15mA.

⑷ Feedback signal of electrical current: AC 12V/15mA three-phase input.

⑸ Phase shift range of rectifying triggering pulse: α＝0~1300.

⑹ Symmetry degree of rectifying triggering pulse: ＜1°.

⑺ Signal width of rectifying triggering pulse: ＞600μs double narrow, interval 60°.

⑻ Characteristics of rectifying triggering pulse: peak value voltage of triggering pulse:≥15V.

   Peak value current of triggering pulse electrical: ≥1A

Fore steepness of triggering pulse: ≥0.5A/μs

⑼ Inversion frequency: 100HZ—10KHZ (Different specification: 100HZ、200HZ、500HZ、1KC、2.5KC、4KC、8KC.)

⑽ Signal width of inversion triggering pulse: 1/(16×inversion frequency)

⑾ Characteristics of inversion triggering pulse: peak value voltage of trigger pulse: ≥22V

Peak value current of triggering pulse:≥3A

 Fore steepness of triggering pulse:≥2A/μs

 (inversion triggering pulse transformer is extra connection)

⑿ The largest size:290×240×30mm

⒀ Failure signal output:

    When fail signal is received by control board, it will output a group of connecting points’ signal. The capacity: AC:5A/220V; DC:10A/28V。

Ⅳ Electrical circuit principle

The control circuit of power supply is made to a printing electric circuit board except the end trigger unit. Its function include power supply, rectifying trigger, adjustor, inversion, start up calculation, etc. All of them are digital circuit, except that adjuster’s is simulative circuit.

The core of the integrate circuit of the control panel is IC6 which is a large special integrate circuit. There are 3 ways of time clock input port, 31 ways input/output port. It’s inside function included: rectifying phase-shift trigger, phase-rotation adaptive, inversion trigger, inversion front-angle locking, inversion restart, over current and voltage protection, phase-failure protection, low water pressure protection, and under-voltage protection of control circuit, there are also three 0.2 second timers.

① Working principle of rectifying trigger

This circuit includes 3-phase synchronization circuit, phase-rotation adaptive circuit, voltage-control clock circuit, digital trigger circuit and end drive circuit, etc.

Signal of 3-phase synchronization is directly from 3-phase input line of main loop, through the gate lead-in K4,K6,K2 of transistors, and it is filtrated by R3,C2,R7,C2,R11,C3, than through 6 photo electric coupler, to get 6 rectangular wave synchronous signal, their phase-rotation difference between each other is 60°, and it is input to 5P-10P of IC6.

There’s an inside phase-rotation adaptive circuit in IC6, so no need to differentiate phase-rotation for 3-phase alternating input of frequency changing source.

IC1C and ambient circuit form voltage-control clock, its signal output cycle linearity changes with output voltage VK of adjustor, voltage-control clock signal is input to 11P of IC6 as digital trigger timers CLOCK.

Digital trigger’s characteristic: to achieve the phase shift by count (clock pulse), 6ways rectifying phase shift trigger pulse are caused by IC6, IC2C, IC2D and other circuit form the pulse wide output circuit. 6ways rectifying phase shift trigger pulse are amplified by IC5 transistor matrix, it drives rectifying pulse transformer to output, here the pulse transformer uses in the way of reverse excitation.

② Working principle of adjustor

There are 2 adjustors. Frequency changing voltage/current adjustor and inversion angle adjustor.

Voltage/current adjustor (IC3C) is a normal PI controller; it runs all the time during startup and run stage. Inversion angle adjustor (IC3B) is used to make the inversion bridge run stably at certain θ angle.

The working process of adjustor’s circuit can be divided into two situations, one is when voltage DC don’t reach the maximum, namely IC3D has no clipping, but IC3A works under clipping state, at this time θ is a smallest, and the system totally is a normal voltage/current closed loop system; another is which voltage DC has already reach the maximum, namely IC3D begin to clipping, rectifying bridge adjustor won’t work any more and IC3A stop clipping state and start to work, to adjust θ angle for a given value, that makes to increase the output of frequency changing, and to reach a new balance. At this time there voltage/current adjustor with inversion angle adjustor work for double-loop.

After signal of frequency changing voltage from frequency changing potential transformer is input by CON2—1 and CON2—2, it becomes two parts, one is sent to 30P of IC6 after level be converted by IC1A, another one after be rectified by D7—D10, is also divided into two parts, one is sent to voltage/current adjustor and another one is sent to over-voltage protection.

The current signal got by the alternating potential transformer of the main loop firstly transfors to voltage signal outside, then be input through CON2—3,CON2—4,CON2—5, after be rectified by diode D11—D16, it is divided into two parts, one becomes the signal of over-current protection, another one becomes feedback signal of voltage/current adjustor.

③ Working principal of inversion part

The inversion trigger of circuit uses frequency-sweep zero voltage softly startup system, it only needs one feedback signal of frequency changing voltage, and no need for the current signal of slot frequency changing capacitor, basically, it will match a separately excited transformation self excited circuit, and is an average value feedback circuit. Because the main loop circuit don’t require any extra startup circuit and prop magnetizing or charging before, the main loop is simple and it’s easy for debugging.

The start up process is that: before inversion circuit start, it uses signal of separately excited to trigger inversion SCR, the signal is higher than slot resonant frequency, when the circuit has detested there’s DC current in main loop, signal of separately excited begins to scan from high to low, at same time it increase DC current of main loop, until separately excited signal frequency goes down to be near slot resonant frequency, the frequency changing voltage is set and feedback to automatic frequency modulation circuit, when it once start to work, to stop that the frequency of separately excited signal is in favour of low range to be scanning, and turns into the automatic frequency modulation circuit to control inversion forward angular for the equipment runs stably.

If once the start up failed, namely automatic frequency modulation circuit doesn’t get the frequency inversion voltage feedback signal, here the signal of separately excited will scan until the lowest frequency, during restart circuit once detects separately excited signal it enters into lowest frequency domain, it will start again, and to drive the signal of separately excited to the highest frequency, and to drive the signal of separately excited to the highest frequency, then will scan again until it starts successfully. The cycle of restart is about 0.5sec.

After to be input frequency modulation voltage signal by CON2—1,CON2—2, which is changing into rectangular wave by IC1A to be sent to 30foot of IC6. The inversion trigger signal which output by 15P, 16P of IC6, it was isolated and amplified by IC 7A, then to drive inversion trigger MOS transistor Q5, Q6. IC4B and IC4C form the inversion voltage-controlled clock which is input to 33 end clock2 of IC6; At same time after converted between frequency and voltage by IC7B, which is used to drive the frequency meter. W6 trimming potentiometer is used to frequency meter. W6 trimming Potentiometer is used to set the highest frequency for voltage-controlled clock (namely, highest frequency for inversion separately excited signal). W5trimming potentiometer is used to turn the reading of frequency meter.

Others, during over voltage protection happens, its over voltage protection oscillator inside IC6 begins to work, it inputs triggering pulse which is two times of highest inversion frequency triggering pulse, it will make 4 transistor of inversion bridge to work.

IC4A is a start-up failing detector, its output will control the restart circuit inside IC6.

④ Start up calculation principle

After over current pertain signal is reversed phase by Q3, that is sent to 20P of IC6, and blocks rectifying pulse, to drive the “O.C” LED indicator lamp to light and drive alarm relay. When over current trigger works, it can run off the machine and then use “electrifying reset”. To adjust W1 trimming potentiometer can tune over current level.

When 3-plase AC input phase-failure, the control board can give protection and indication for power source. The principle is that: to get A、B、C 3-phase voltage signal by cathode(K) of 4#,6#,2#SCR (though gate lead-in), and the signal is isolated by photo-electric coupler and then it is sent to IC6 to detect and distinguish, once phase-failure happens, except that blacks rectifying triggering pulse, it will need to switch on “O.P” LED indicator lamp and drive alarm relay.

In order to control circuit works more reliable and true, it has start up timer and sets control source under-voltage detection protection. At the beginning of start up, the control circuit working doesn’t stable, to set a timer its time is about 3 sec, after timing that is allowed to output triggering pulse. IC2B etc form its circuit. If some problem caused volt D.C supply in control board is lower or voltage stabilizer doesn’t work, that will make the control process to appear a mistake, to have need to set a under-voltage detection circuit (be made up of IC2A, etc), during VCC voltage is lower than 12.5V, that needs to block rectifying triggering pulse avoid wrong triggering, at same time switch on “L.V” LED indicator light and drive alarm relay.

Automatic restart circuit is inside IC8, the trimming switch DIP-1 is used to turn off automatic restart circuit.

Q2 forms reversion frequency over voltage detection, and that is input to 29P of IC6, to block rectifying triggering pulse and switch on “O.V” LED indicator lamp and drive alarm relay, at same time make over voltage protected oscillator to work. After over voltage protection working, it also can run again only through reset signal, or try the way that first turn off the machine and then use “electrifying reset” to restart. To adjust W2 trimming potentiometer can turn over voltage level.

Water under-pressure time delay protected circuit is made up of IC4D and other circuit around, its delay time is about 3 sec, that is input to 27P of IC6, and block rectifying triggering pulse, switch on “W.P.L” LED indicator lamp and drive the alarm relay. After water pressure is natural, the circuit resumes normal working automatically.

Reset switch signal is input by CON2—6, CON2—7, its closed state is reset/pause.

The clock signal clock1 is input to 35P of IC6, its time cycle is 20ms.

Ⅴ Control system

A、The medium frequency power control system uses the digital control technology completely; all the control function concentrates on single printed wired assembly, the core part of motherboard is the large-scale controlled digital circuit module. Using the intellectualization and the adaptive control technology, cause rectifying triggering and inversion triggering do not need any adjustment, moreover it has high reliability, high pulse symmetry, and good anti-interference capability, fast reaction speed.

B、 The digital rectifying control section uses the single-phase synchronized signal, the synchronized signal is filtered by the digital filter, even if the electrical network voltage is seriously interfered, the digital filter still can locate the synchronized spot accurately, the synchronized signal carries on the digital phase decomposition inside the micro controller, decomposes for three-phase, the phase-decomposition error does not surpass 0.1 degree, the digital phase decomposition has track and locking function of the electrical network frequency, even if the electrical network frequency changes in the range of 45HZ~55HZ, the digital phase-decomposition still can track accurately, causes the angle of rectifying pulse maintain invariable, the digital rectifying control can guarantee the mutual phase error of 6 groups triggering pulse which is final sent to the rectifying silicon-controlled rectifier is not bigger than 0.15 degree, thus causes the unbalanced coefficient of input current of medium frequency power is smaller than 5%.

4) Body parts
Magnetic steel used hydraulic transmission Conjugate structure, by the shell, sensors, magnetic conjugate, refractories, dumping furnace, water-cooled cable component.
4.1, Shell: The ring made of thick steel tube frame Park, sufficient to ensure the sensors and lining the rigid, tendons furnace at the bottom bearing plate with a radial, for cooling.
4.2, sensors: 5 mm thick-walled rectangular brass, from top to bottom around the two-story parallel system, set up at both ends of the water-short circuit, Central Circle, the maximum to avoid heating furnace shell.
4.3, magnetic conjugate: Profiling create a cross-section, and pressure sensors affixed by some to create a certain arc, for working closely with the pressure sensors affixed to reduce air gap, to improve the magnetic field shield have more benefits, so that sensors installed more Solid and difficult to vibration and greatly improve the lining life. Magnetic yoke and the top coil flat bottom to the furnace at the bottom shell. Magnetic yoke with 0.3 mm thick layer of quality from Xi Gangpian, sensors and the outer surface coverage> 60%.
4.4, the dumping furnace Drive: hydraulic, fuel tanks bore Φ200. Body leaning forward the maximum angle of 93 °.

1) sensors
Sensors is the heart of the furnace, it is not only a direct impact on the absorption power furnace, the reasonableness of its design and manufacturing quality of life directly affects the lining. Sensors aloof from welding in the series bolt circle and insulation hold fixed. Coil in the upper and lower water-cooling system are equipped with stainless steel ring, with the aim of the lining material in the axial heat evenly, extending the life of lining.
My company's sensor has the following characteristics:
a) sensor parameters set by the computer to complete, according to the requirements of user productivity and capacity of the furnace size, design staff Congyou elected power, power factor, coil turns, coil height, power efficiency, thermal efficiency, and so the best combination of parameters.
b) in structural design used in a leading position in domestic short-circuit ring design, the complete elimination of the intermediate frequency heating furnace component of the phenomenon.
c) the traditional sensors - burden generated by the system design of the weak and electromagnetic stirring lining at the bottom of the serious erosion, is lengthened by a coil structure, not only increased the electromagnetic force and reduce the mixing of the liquid steel at the bottom of the erosion of the lining . Greatly improve the life of the lining. Figure its electromagnetic theory.

 

I produced a thick wall sensors are used for high-quality T2 Zi Tongguan in the winding-made devices around the technology and equipment to ensure the manufacturing quality and the formation of the coil wall to further improve the life of the lining. Selection by the thick wall of the Zitong Guan, improve efficiency.
2) Magnetic conjugate
Use of high-quality cold-rolled silicon steel sheet, to minimize magnetic loss, increased electromagnetic coupling efficiency. Silicon steel sheet for the thickness of 0.3 mm. Conjugate by copying magnetic structure, its Globoidal within the arc and induction coil of the same cylindrical arc so that the magnetic induction coil conjugate can keep abreast of the lateral, the maximum restraint divergence of the magnetic field coil, reducing the magnetic circuit reluctance.
Magnetic yoke from the side of the stainless steel plate and stainless steel clip of gripping, welding fixed. In the side of the stainless steel plate welding a cooling water pipes, used for cooling magnetic yoke. Cooling water pipes can withstand 0.45 Mpa pressure without leakage.

3) leaking furnace and the water temperature alarm devices, water pressure alarm device
Throughout the induction coil vertical electrodes evenly distributed, and accurately detect the induction coil changes in the lining erosion, these signals will be transferred to the resistance values on the display so as to achieve the objective of the police.
Water temperature, water pressure alarm, before the use of hydraulic pressure and temperature settings, when more than set below the set temperature and water pressure alarm.
4) fixator
By steel welded together, on the plane by a large planer from processing to ensure that the rotary housings for the Care and assembly accuracy.
5) the introduction of water and electricity systems
Body of water between the two parallel systems, using general softened water, use of natural cooling water cooling towers or cooling, power supply cooling the best use of the cooling towers closed cooling system with a water softener.
    The introduction of the hydropower system features:
    a. furnace cooling water into a unique single-out single, and out of the water pipe used flange ports, user-friendly installation, to solve the use of Multi-rubber tube connected and do not have a smooth flow, and plug the rupture, increase utilization of the stove.
b. the introduction of water and electricity are used side Chuxian form, reducing the line losses, improve the water-cooled cable life.
c. water system in every branch on the water each have a temperature sensor, the temperature is higher than when the alarm settings. In-roads into the water pipes with water pressure regulator, when the water pressure below the set value of alarm.
d. water-cooled cables: Cold pressed Process and copper stranding Press. This link fastening, the contact resistance of small, non-injury and rapid replacement of copper wire, can withstand the pressure of 0.5 Mpa not leak or rupture.

6) Hydraulic devices
Including hydraulic station and the dumping furnace Caozong Tai. See the principle of hydraulic schematics.
Body Pump Station for dumping stoves and other campaign momentum. Pumping Station rated pressure for 12 Mpa, working media for wear-resistant hydraulic oil.
The traditional dumping furnace Cao Zongtai to manually dump valve furnace, its shortcomings: the life of electrical components not protected, in particular, the system must be unloading of specialized operations, the actual use of the system vulnerable when the adverse consequences of high oil temperature .
I used exclusively in the domestic multi-valve after the complete elimination of the above shortcomings. Cancellation of the electromagnetic valve, switch, load button, and other electrical components, the dumping furnace operation through manipulation of multi-valve on the handle to achieve.
Dumping the fuel tank of a furnace cylinder plus guards. Reduce the flying of hot metal and other foreign bodies fall on the surface of the plunger possibility of raising the fuel tank of life.
5) technical information and drawings
     Factory equipment to provide the following technical information.
1, mechanical parts
Including infrastructure plans, layout plans, civil engineering requirements, platforms and cooling system, power Manual, the use of electric furnace maintenance manuals and operational procedures IF power notes.
Hydraulic schematics, hydraulic station and dumping the furnace console plans and hydraulic parts list. Hydraulic System Manual.
2, electrical parts
Including the main circuit electrical schematics, external wiring diagram, IF Power Maintenance Manual, the control system failure ruled out inspection guidance manuals.
All drawings and technical information on a duplicate. In the contract after the commencement of advances to two weeks after the delivery, drawings and other technical information with the equipment delivered.

6) The pre-inspection equipment and training
In all the equipment manufacturers has been completed, the buyer the invitation of the technical staff to the equipment manufacturing plants, to participate in the pre-inspection equipment and training.
6.1 Pre-acceptance content
1) general inspection
2) security check
3) Body size detection assembly
4) induction loop insulation manufacturing quality inspection and pressure test
5) induction coil and the electric space heaters shell measuring
6) and the furnace shell coil insulation resistance measurement
7) and the furnace coil magnetic yoke of insulation resistance measurement
8) IF furnace insulation pressure test
9) the hydraulic test coil
10) matching pieces of inspection, including models, specifications, pre-certification inspection
11) Availability of pre-check the integrity of the technical documents
6.2 Training
The seller to the buyer to do the following technical training:
1) the installation of training equipment
2) electrical control design principle of the training (including: electrical design of the protection, monitoring, fault display, etc.)
3) equipment repair and maintenance work of the day-to-day training
4) Common equipment failures and the failure to exclude special training
More than content to be in training for the location.
6.3 Acceptance of all the projects and pre-test data, the two sides should have the presence and participation in the signing, at the same time supply the buyer archive.
Only 6.4 completion of pre-inspection work and the two sides agreed after the signing, the seller can packaging equipment will be shipped.

7) the installation and commissioning final acceptance
7.1 After the installation of equipment, equipment installation and accuracy checks, and then cooling equipment, heat debugging. Each normal smelting furnace, 10, (auxiliary materials, including sea water pipe system connected to the equipment out of the water equipment port, quartz sand, clay sensors, hydraulic oil from the users own);
7.2 seller experts at the scene, the buyer equipment operation and maintenance staff in the operation and maintenance of equipment training.
7.3 Acceptance of the equipment should be in the final buyer users at the scene, acceptance of the project include:
1) to counter the electrical insulation testing;
2) Body sensors on the check;
3) electrical cabinets and the relative phase of the inspection;
4) Check the cooling water, electrical parts, water pressure ≥ 0.1 Mpa, furnace parts water pressure ≥ 0.25 Mpa, the water temperature is greater than 5 ℃ less than 35 ℃;
5) Check the hydraulic system, hydraulic pressure for 12 ~ 15 MPa;
     6) induction furnace Power Measurement (Scrap yield ≥ 97%, lightweight materials must be packaged into Press);
     7) induction furnace and the melting rate of power consumption measurements (Scrap yield ≥ 97%, lightweight materials must be packaged into briquettes, except for insulation);
8) the alarm system reliability and sensitivity of the inspection;
9) equipment to be run by IF Power notes the implementation of operational procedures;
  All projects after the completion of inspection tests, write a final inspection report, the two sides signed authorized the entry into force.
8) product quality control measures
The quality control of raw materials and accessories, including inspection of the production process control and testing manufactured products.
Raw materials and accessories in the selection, I selected domestic brand-name companies adhere to Sino-foreign joint ventures of enterprises and products, give priority to the ISO9001 standard certification enterprises. Raw materials and accessories, specifically into the plant after the inspectors carry out their inspection, including material certificates, certification and internal quality checks.
In the production process, each of the quality of parts and components have responsibility for tracking cards, each describing the responsibility of processing steps and a final inspection personnel. For key components such as sensors, magnetic conjugate technology, and so have special codes.
Products factory to conduct pre-test. Includes appearance inspection, mechanical inspection size, the induction coil insulation inspection, testing and hydraulic pressure test. After all inspections by qualified inspectors complete the product certificate.

1.                      9) quality assurance
The furnace is used new equipment, technical specifications and equipment corresponding to that of high-quality materials, equipment and all the substantive aspects of technical specifications in line with the requirements.
The main equipment, accessories are the factory certificate of competency issued by the product.
9.1 EAF equipment since the end of qualified acceptance from the date of six months for the warranty period. In the warranty period, the manufacturing equipment due to bad or poor quality of parts caused by failure, the buyer for the free repair or replacement of the corresponding parts.
9.2 rated tonnage and equipment to power, during the commissioning of the components responsible for the total.
9.3 pairs of the following components repair kits Baohuan six months (to wear furnace, water and electricity, except for wearing parts, such as the rapid melting, SCR, etc.): 1) open space, 2) electric capacitor 3) Hydraulic devices; ) Reactor line package; 5) furnace, 6) the main control panel.
10) Technical Services
10.1 According to the buyer production workshop status quo, provide a full range of the electric furnace equipment and basic layout design. Design Institute and the buyer and related technical Jiaodi.
10.2 provide the buyer with all equipment related to external parameters, including water, electricity, gas and other requirements. To assist the buyer of the external equipment or material selection.
10.3 pairs of the buyer's operation and maintenance personnel to free technical training. Skilled operators to ensure that the equipment operators, maintenance personnel can carry out routine inspection of the equipment, determine the point of failure and replacement of equipment damaged components.
10.4 in the durability period of free maintenance of equipment.
10.5 Upon receipt of the buyer maintenance requirements after four hours to respond within, the durability period of maintenance personnel arrived within 48 hours of the buyer at the scene. To ensure the stability of parts and components production, the discount long-term (less than the same period the market price) to the buyer to provide spare parts.
10.6 Free debugging (at home), all the costs of seller’s experts go and work at abroad for return air tickets, accommodation and meals, will be borne by the buyer. The buyer shall compensate the experts at USD 150 per day for debugging period. After normal operation the seller should be responsible to guarantee repair or change of the faulty components in 6 months, such as master control board, reactor, compensate capacitor, hydraulic device, breaker, and furnace shell (except for lining break through, stoppage or shortage of cooling water supply for components).

10.7 send technicians Mill commissioning services after the end of 10 days.

 

11）一套15T功率8000KW中频炉设备清单及供货范围

 

1 set of Medium Frequency Furnaces, Equipment list and supply range

序号 No.	设备名称 Description		单位 Unit	数量 QTY	单重 Single Wt (t)	总重 Total Wt (t)
1	12T中频感应炉体	12T Medium-frequency Induction furnace	台/set	2
2	低压配电柜	Low voltage power cabinet	台/set	4
3	中频电源柜	Medium-frequency Power cabinet	台/set	4
4	电热电容器柜	Compensate capacitor banks	台/set	1
5	液压系统	Hydraulic system	套/set	1
6	倾炉操作台	Furnace tilting operation desk	套/set	1
7	水冷电缆	Cooling water cable	条/set	20
8	中频电源至电容柜连接电缆	from Medium-frequency power bin to capacitor bank	条/set	8
9	坩埚模	Crucible mould	只/set	1
10
11	电缆托架	Cable bracket	付/set	2
12
13	水温水压报警器	Temperature /pressure alarm system	台/set	1

 

12) 12T/8000KW induction melting furnace steel hydraulic random parts:
1) SCR KP, KK each one
2) a control board

 

13) Team of payment: Buyer pay 40% of full value in advance, when the goods deliver the buyer pay 60% of full value.  

14) Price: Whole set (not including transformer and cost of freight, package, installation and adjustment)

15) Delivery time: 90 days