20t smelting electric furnace

20t MELTING INDUCTION FURNACE

TECHNICAL CONTRACT

1、概述 GENERAL

感应熔化炉采用电磁感应原理，将电能转化为被加热金属中的感应电流，使金属发热直至熔化，适用于金属材料的熔化浇铸工艺。小容量的感应炉采用铝壳结构，大容量的感应炉体采用钢结构外壳。根据用户的投资和生产要求，选择最适合的炉体结构，确保最佳效益。

感应熔化炉的成套设备，主体设备为整流变压器、中频电源柜、中频补偿电容器柜,电抗器,水冷电缆和感应熔炼炉。为确保主体设备正常工作，必须配套使用的辅助设备有循环水冷系统、倾炉液压系统。

The melting induction furnace comes from electromagnetic induction theory, it changes electrical energy to magnetic energy, which induces current flowing in metal material. The metal then is heated up to melting point by the inductive current. Usually small volume induction furnaces adopt aluminum alloy frame, and the great volume furnaces all use steel frame combined with silicon-steel to shield the flux leakage. Users can choose suitable furnace type according to the requirements of manufacture and scale of investment, so as to obtain the optimum benefit.

The essential equipments of induction furnace include power transformer, medium frequency power supply, compensative capacitors,reactor, furnace body, hydraulic station, and cooling water system. Of course, the connection cable and conductive copper bar is necessary.

2、 整流变压器 Rectifier transformer 

2.1功能及结构  Function and structure 

包括变压器本体、膨胀油枕及变压器本体所带全部附件。变压器的冷却方式为强油水冷方式，因此要求变压器的冷却水为城市软化水。

This equipment includes main body of transformer, force oil water cooler, oil-expansion vessel and all accessories of transformer. It is cooled by oil-water cooler,so cooling water should be city water +softener .

变压器配有重瓦斯、轻瓦斯、释压器等保护功能，并配有油温检测元件，可实现高温报警和超温跳闸保护。

The transformer has such protection function as double float buchholz relay, pressure relief device. The transformer also has oil temperature testing device to give alarm and protection.

另一个特点是整流器用的变压器，其短路阻抗应比普通变压器略高，通常在8~10%（普通变压器在4~6%），以利于降低整流器的换流电压尖峰。

Another specification of power transformer for rectifier’s requirement, is the short-circuit impedance. It should be a little greater than that of common transformer, usually the impedance should be 8~10%（for common transformers ,the value is 4~6% or so）, it is helpful to suppress the voltage surge caused by rectifier commutation.

2.2技术参数 Parameter 

3、 中频电源 Medium frequency power supply 

3.1功能及结构  Function and structure 

电源柜采用GGD型标准柜结构，三节分柜固定在一个槽纲底座上，相互之间也通过固定件连接，组合成一个整体。内部安装的电器元件主要包括低压空气断路器、快速熔断器、整流器、逆变器以及各种控制变压器和驱动元件。电柜门上安装有各种显示仪表和操作按钮。作为控制系统核心的主控制板也安装在电柜门上。

由于总功率达到12000千瓦，必须采用两台上述的组合电柜，每台输出6000千瓦。同时两台共四套整流器共同实现24脉整流模式。

中频电源具有多种基本的保护功能，如输入过电流、输入欠电压、输出过电压、冷却水压低、冷却水温高等。其他各种保护功能如炉体的保护也输入到主控制板中。

The power supply cabinet adopts GGD type standard cabinets, 3 small cabinets are fixed on the whole channel steel base and combined through screws with each other to form a whole. the main electrical devices installed inside include air circulation breakers, quick fuses, rectifiers, inverters, all kinds of control transformers and drivers. Also all instruments and operation buttons are installed in the doors. The main control circuit board, as the heart of the whole control system, is also installed in the doors.

Because of the great power of 12000KW, 2 combined cabinets are used, each supplying 6000KW. Also 4 rectifiers of the 2 cabinets carry out the 24-pulse rectifying mode together to reduce the harmonics content.

The power supply has several essential protection functions, such as input-overcurrent, input-voltage-lower, output-overvoltage, inlet-cooling-water-pressure-lower, outlet-cooling-water-temperature-higher and etc. Other protection signals from outside such as furnace protections can also be inputted into the board through spare terminals.

3.2技术参数 Parameter 

3.3 参考图Reference drawings

电源柜的外观示意如下，它由3节组合而成。整流柜的顶部进线输入端口采用铜排与变压器的二次侧对应连接，逆变柜的底部是中频输出端口，采用水冷电缆与电容器器柜的输入铜排相连。

The appearance of power supply cabinet is as follows, it consists of 3 small cabinets. The top input terminals are connected with the secondary windings of the transformer by copper bar, and the base output terminals are connected with the input copper bar of capacitor cabinet by water cooling cables.

电柜尺寸Cabinet Size：L3600×W1000×H2500

4、 滤波电抗器 FILTER REACTOR 

4.1功能及结构  Function and structure 

电抗器也称电感，由铁心和水冷线圈组成，通过水冷电缆连接在整流器的输出直流母线和逆变器的输入直流母线之间，以稳定输出电压并减小中频电压对电网电压的干扰。

The reactor is also called inductor, it consists of silicon steel core and water cooling coil, and is connected by water cooling cables between the DC-bus of rectifiers and inverters, to keep the MF voltage stable and prevent the MF output from interference with the input voltage.

4.2技术参数 Parameter 

4.3 参考图Reference drawings

5、 电容器柜 CAPACITOR CABINET 

5.1功能及结构  Function and structure 

电容器柜与感应线圈并联连接，用以补偿感应线圈的感性无功功率，同时与线圈构成一个谐振回路，达到适合的频率和等效阻抗。经过补偿后，中频电源只需提供负载所需的有功功率和少量的无功功率，中频电源的容量可大幅度减小。

The medium frequency capacitor cabinet is paralleling connected with the induction coil, compensating the reactive power of the coil, and constructing a suitable network with proper frequency and impedance. Therefore, the inverter only needs to provide the active power and a little reactive power that are necessary for loading; the inverter capacity can be reduced greatly.

大功率感应炉需要大量的补偿电容器，为减小占地空间，减小电磁泄漏，我公司的电容器柜采用独特的双层安装模式。大电流的水冷母排采用特殊模具订制，水冷腔与铜板一次成型，无需焊接，因此无氧化，水冷和导电效率高。

For high-power induction furnace, a large number of compensation capacitors are necessary. We adopt the unique mode of double-layered layout, which engrosses just a little area and has a little electromagnetic leakage. The water-cooling bus bar of the capacitors is specially manufactured; copper bar and water channel are wholly drawn to be molding without welding oxidation and are highly effective and shapely.

电容器的布局采用了抽屉式结构，只要松开单个电容器的固定螺丝，就可象拉动抽屉一样取出电容器，更换电容十分方便。

The mode of drawer installation is adopted for capacitor layer-out. As long as loosing the screw connected with any capacitor, the capacitor can be pulled out as a drawer, which is convenient for replacement.

5.2技术参数 Parameter 

6、 换炉开关 FURNACE ALTERNATION SWITCH 

6.1功能及结构  Function and structure 

换炉开关用于将电容器柜与两只炉体中的某一中相连接。一只炉体处于工作阶段时，另一只与电容器脱开，便于打结炉衬和维护保养。

The switch connects the capacitors with one of the two furnaces alternatively. When onqe furnace is in use, the other is disconnected from capacitors so as to .

6.2技术参数 Parameter 

7、 感应炉INDUCTION FURNACE 

7.1功能及结构  Function and structure 

由炉体固定架、炉体框架、感应线圈、磁轭、倾炉液压缸组成。炉体固定架采用型钢和钢板焊接而成，现场安装时将固定架焊接在炉体基础预埋钢板上。炉体框架由H钢复合加强筋板构成。框架式结构便于维修保养。正常工作时，通风排气，散热良好。

The equipment consists of holding base, furnace body, silicon steel yokes, hydraulic cylinders, etc. The furnace body is made up of section steel and reinforced by steel plate. We adopt frame structure, the skeleton is welded together by H steel and plate steel. Such structure is helpful for air circulation, maintenance and inspection.

感应线圈是感应炉的核心部件，它由坚实耐用高导电的冷拔铜管制成。线圈表面刷涂一层高温绝缘漆。线圈匝数适当，能获得最大的电、磁效率。磁轭采用低损耗优质硅钢片、不锈钢夹板水冷，硅钢片冲孔用不锈钢螺杆套绝缘套管对穿锁紧，整体强度高，接触紧密，散热性能好。

The induction coil is the key part of the whole furnace, it is made up of cold-pressure copper tube, with high density and good conductivity. The surface of copper pipe is brushed with insulation paint which can bear high temperature and voltage. The coil turns come form accurate design, ensuring the optimum electromagnetic efficiency. The yokes are made up of qualified silicon steel with lower energy loss, and are screwed by stainless steel bolts, which ensure good strength and heat conduction.

7.2技术参数 Parameter 

7.3 参考图Reference drawings

（a） outlook sketch

Characters in the chart：

出钢口: Tapping Hole，电缆连接排: Cable connection copper bar，

线圈水咀: Coil water nozzle，倾炉液压缸: Hydraulic cylinders for tilting furnace，

用于炼钢的感应炉，我们建议不必要采用保温炉盖，因为炼钢的原料多种多样，每炉的加料次数频繁，炉盖频繁开启和关闭，影响生产，也导致炉盖机构寿命不长。炉盖比较适合铸造类的用户。

For melting induction furnaces used with continuous casting machine , we think that the holding cover is unnecessary. because the charges is various, and put into the furnace continuously, cover should be opened and closed frequently. Thus the frequent operation of cover installation will affect work efficiency, and the life-time of cover will be shortened. The holding cover only suits such users as molding cast, etc.

8、 水冷电缆 WATER-COOLING CABLE 

8.1功能及结构  Function and structure 

水冷电缆有铜绞线和铜棒制作而成，外套高压橡胶软管。其中铜绞线和铜棒之间是通过100吨液压模具冷压成型，没有焊接存在的诸多弊病，如氧化，温度偏低导致的虚焊，温度过高导致的熔断等。

The water cooling cables are made up of copper strand and copper rod. The joint between the strand and rod is carried out by cold-pressing with 100-ton hydraulic mold. Compared with the traditional oxygen welded joint, this method has no the disadvantages such as oxygenizing, poor contact due to lower welding temperature, welded breakage due to overheated, etc.

8.2技术参数 Parameter 

9、 液压泵站 HYDRAULIC PUMP STATION 

9.1功能及结构  Function and structure 

泵站由电机、液压泵、油箱和数种电磁阀组成，用于倾动炉体。泵站具有油位指示，回油过滤器，及过滤器压力报警。系统设置了两套电机和油泵，一套使用，另一套备用。

The pumping station consists of motor, hydraulic pump, oil tank and several kinds of electro-hydraulic valves. It drives the motor and pump to tilt the furnace. It has oil level indicator, oil filter, and oil filter pressure testing device. Two sets of pumps and motors are used, one in running, and the other in ready.

9.2操作方式 OPERATION MOED 

液压操作方式采用电控方式，只需要一根电缆连接的控制盒，3只按钮，分别控制上升、下降和紧急停机。泵站的电控箱安装在炉台的墙壁上，需要倾炉时，按动电控箱上的启动按钮，即可启动电机和油泵，然后手持控制盒即可控制炉体的动作，无需在炉体平台上设置操作台。

The hydraulic tilting system adopts electric valve control mode, only one control box connected a cable is used. 3 buttons are on the box, respectively for tilting up, tilting down and emergency stop. The power switch case for pump station should be installed on the platform wall, when tilting the furnace, pushing the start button to run the pump and motor, then operators only are needed to catch and operate the control box to tilt the furnace to any position. The hydraulic operation desk is no needed to be installed on the furnace platform.

9.3技术参数 Parameter 

10、 成套范围 :每套20吨中频炉的供货范围如下表 

Supply range of 1 complete set of 20-ton induction furnace shown in the below table.

13、技术参数 Technical data for 20-ton IF

备注：以上表中参数是指连续热炉、块料、满炉加料及废钢收得率≧97%的工作指标。

NOTE: the above data is due to continuous running with hot lining, mass scrap, full charge, and scrap yielding rate ≧ 97%.