The Structure and Working Principle of ERW Carbon Steel Pipe Equipment

Understand the principle of erw carbon steel pipe, but also have the necessary technical means to achieve it. High-frequency welding equipment for erw carbon steel pipe is used to achieve high-frequency welding of electrical - mechanical systems, high-frequency welding equipment is made of high-frequency welding machine and pipe forming machine. One high-frequency welding machine is generally composed of high-frequency generator and two parts of the feeder device, its role is to produce high-frequency current and control it; forming machine by the squeeze roller frame, its role is to be high-frequency current The molten part is squeezed to remove the oxide layer and impurities on the surface of the steel plate, so that the steel plate is completely melted into one body. High-frequency generator used in the past, the use of high-frequency generator on the high-frequency generator is three circuits: high-frequency generator; solid-state inverter; electronic high-frequency oscillator, and later basically improved to a single circuit. There are many ways to adjust the output power of the high-frequency oscillator, such as autotransformer, reactance method, thyristor method and so on.
  
Feeder is used to transfer high frequency current to the tube, including the electrode contacts, induction loops and resistors. Contact welding is generally used wear-resistant copper tungsten alloy electrode contacts, induction welding is used in the copper induction coil. The main component of the resistor is the core, its role is to increase the resistance of the surface of the tube to reduce the invalid current, improve the welding speed. The core of the resistor uses ferrite, asking its curie temperature is not less than 310 °, Curie point temperature is an important indicator of the core, curie point temperature is higher, you can rely on the closer from the weld, The closer the welding efficiency is higher.

Each inverter module constitutes a full-bridge IGBT transistor inverter. The drive circuit of the transistor is on a printed circuit board in the inverter module. DC from the inverter into high-frequency alternating current. Depending on the load, the frequency of the alternating current is in the range of 100-150KH. In order to adjust the inverter according to the load, all the inverters are connected in parallel with the matching transformer. The transformer has several parallel windings, and a secondary winding. The turns ratio of the transformer is fixed.

The output capacitor consists of several parallel capacitor modules. The capacitor is connected in series with the induction coil, so the output circuit is also compensated in series. The role of the capacitor is based on the induction coil reactive power requirements to compensate, and through this compensation to make the resonant frequency of the output circuit to the required value.

This frequency is then used as the time base signal for the transistor. The transistor drive card sends a signal to each transistor on each inverter module to control when the transistor is turned on and when it turns off. The output power control of the induction heating system is controlled by controlling the output current of the inverter. The above control is done by a power control card used to control the transistor driver.