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Intermediate frequency induction heating copper tube annealing equipment

Intermediate frequency induction heating copper tube annealing equipment


1 , Overview:

Intermediate frequency induction heating copper tube (copper tube ) annealing equipment is suitable for on- line annealing of copper tubes (brass alloy outer sheath). The penetration depth and hardness are according to the specific requirements of customers to achieve stress removal and softening of brass alloys. The purpose of the outer sheath.

Equipment introduction The complete set of equipment is designed and manufactured according to the mechatronics structure. Among them, the intermediate frequency power supply is a set of 6- pulse thyristor KGPS200KW/8KHZ intermediate frequency power supply, the load is a set of GTR series induction heating furnace, and the equipment is equipped with a set of reactive power compensation capacitor bank. The device is designed with manual and automatic power adjustment knobs, among which automatic is the temperature closed-loop control mode. The external control console adopts PLC (Siemens) and touch screen control. The heating parameters can be easily input on the touch screen, such as copper tube specifications, heating speed, annealing temperature, etc. After the parameters are input, the closed loop control system of the intermediate frequency power supply temperature will automatically adjust the output power, thereby Meet production needs. When a certain part of the production fails, the intermediate frequency power supply can be insulated according to the set temperature to avoid over-burning the copper tube . The equipment is placed according to user requirements, facing the equipment from left to right, the operating table is placed toward the main equipment, which is conducive to the operator to observe the production situation and facilitate the adjustment of parameters.

Safety protection The equipment has complete safety protection measures, such as water shortage protection, phase lack protection, over current protection, over voltage protection, under voltage protection, high water temperature protection, etc., and there is an audible and visual alarm device for faults. The equipment is configured according to 200KW , leaving enough power margin to ensure continuous and stable production of the equipment for 24 hours. All exposed conductors are installed in the electric control box with a lock, and there are eye-catching safety reminders, so no electrical safety accidents will occur. Each interlocking device can avoid damage to the equipment or copper pipe due to manual misoperation .

Equipment structure The complete set of equipment covers an area of ​​about 2000*1500mm , with a center height of 1000mm . The power supply is integrated with the heating furnace body, and the expansion bolts are used to fix it. The equipment is designed with an external console, which can be arranged at will according to the site conditions, which is convenient for operation. The installation of the equipment is simple and quick. Users only need to connect the water inlet and outlet pipes with the water inlet and outlet pipes of the equipment (one nozzle for each water inlet and outlet), and connect the three-phase four-wire to the upper end of the equipment.

2 , induction heating copper tube annealing apparatus

technical parameter

2 .1 material technology parameters

Workpiece material: through ground wire (the inside is a copper stranded core conductor, and the outside is tightly covered with a brass alloy outer sheath)

Annealing method: online continuous induction heating

Material specifications: φ 6- φ 13mm , wall thickness 1mm

2 .2 heating main technical requirements

Initial temperature: 20 ℃;

Annealing temperature: controllable and adjustable within the range of 600 ℃; the temperature testing accuracy of the brass alloy layer is ± 5 ℃, and the temperature control accuracy of the induction heating is ± 20 ℃.

Heating depth: 2mm ;

Process line speed: within 30m/min (maximum line speed is not higher than 30m/min );

Center height of production line: 1m ;

2.3 Technology selection of complete equipment

The complete set of equipment includes intermediate frequency power supply control system, far-infrared optical fiber temperature measurement system, temperature closed-loop control system, reactive power compensation capacitor bank, induction heating annealing furnace body, etc.

Intermediate frequency power control system:

2.3.1 The  intermediate frequency power supply is a thyristor variable frequency device, the input voltage is 380V , 50Hz , and the output power is 200KW . The power can be adjusted manually or automatically according to the set temperature. The output frequency is 8KHz (automatic frequency tracking). The color of the cabinet is determined according to the user’s requirements, the outline size is 2000 × 1500 × 1300mm , and the center height is 1000mm .

2.3.2 Cartridge type combined silicon rack

The rectifier and inverter part of the thyristor adopts the latest modular combined silicon frame with patent application. This installation method makes the disassembly and assembly of the thyristor more convenient and scientific. When replacing the thyristor, just loosen it A tightening bolt can replace any thyristor element in the assembly. Moreover, this installation method fully reduces the volume of the SCR component, which not only increases the operating space in the electrical cabinet, but also greatly reduces the line loss.

2.3.3 Large-capacity DC smoothing reactor

Smoothing reactor is very important for solid power supply, it has two functions. First, make the output current of the rectifier smooth and stable. Second, when the inverter thyristor is short-circuited, the growth rate of the short-circuit current and the size of the maximum short-circuit current are limited. If the parameter design of the filter reactor is unreasonable, the core material is not good or the manufacturing process is not good enough, it will have a great impact on the working reliability of the intermediate frequency power supply.

2.3.4 Large-capacity SCR

In order to ensure the reliability of equipment operation, both rectifier and inverter thyristors use Xiangfan station-based large-capacity KP and KK silicon to ensure the stable operation of the equipment.

2.3.5 Use series and parallel compensation lines to reduce the loss of transmission lines

In order to reduce the loss on the intermediate frequency transmission line, the compensation capacitor of the inverter is connected in series and parallel voltage doubling form

2.3.6 Main circuit parameters and component selection basis

The rated parameters of the main circuit of the intermediate frequency power supply are shown in the following table :

Term project KGPS200/8
Input voltage ( V ) 38 0
DC current ( A ) 400
DC voltage ( V ) 500
Induction coil working voltage ( V ) 750
Working frequency ( H z ) 800 0

2.3. 6 induction heating copper tube annealing apparatus

The inductor is composed of a furnace shell, an induction coil, a stainless steel water collector and a furnace lining. The induction coil is combined with the parameters of the annealed copper alloy tube to optimize the design with special computer software and make it in combination with actual experience. It can ensure the best electromagnetic coupling efficiency under the same capacity. Induction coils with 99.99% of T2 rectangular brass winding made, the induction coil outer insulating electrostatic spray process the epoxy resin insulating layer of high strength, pressure-resistant insulating layer is greater than 5000V .

The inner layer of the induction coil is made of white corundum lining, and the outside of the lining and between the coils are fixed with refractory cement (American Union Mine), which can play a role in insulation and heat preservation. At the same time, the strength of the white corundum lining is further increased, effectively avoiding copper pipes from damaging the lining.

All the water in and out of the sensor is collected into two stainless steel water traps, which are connected to the main water inlet and outlet pipes. The stainless steel water collector is beautiful and practical, which can effectively avoid the influence of the heat dissipation of the induction coil due to the corrosion of the water pipe and the blockage of the waterway.