As shown in the figure, the principle of the conductive electromagnetic pump is that when the conductor in the magnetic field passes through the current, the conductor will be pushed by the magnetic field. The three directions are perpendicular to each other, and the thrust is f = I× B.
The conductive electromagnetic pump has no rotating parts, which solves the wear problem of mechanical pump and forms a maintenance-free welding machine. However, in the process of conducting current from a large current electrode in contact with liquid metal, the peak value is unstable or even fluctuating due to the adhesion and shielding of oxide slag on the electrode, which makes it impossible to produce stably. Nearly 50 models imported from Switzerland by China were basically stopped.
2. Principle of induction electromagnetic pump
The principle it adopts is to use a single-phase C-shaped open-ended electromagnet to generate the phase difference of the inner and outer magnetic fields due to the magnetic circuit difference, and then form the forward magnetic field component, that is, the forward magnetic field component from the leading phase to the lagging phase. The liquid metal solder in the advancing magnetic field component cuts the magnetic field lines, so it is subjected to a positive induction force to achieve the purpose of pumping the liquid metal solder.
Because the phase difference is generated by the magnetic circuit difference, the forward magnetic field component is very limited, and most of them are pulsating magnetic fields that do not generate forward thrust, so it is very difficult to manufacture wide peaks (300 mm to 400 mm in width) and ultra-high peaks (40mm in height) as shown in the figure.
3. Principle of three-phase asynchronous induction pump
This is another patented technology of wave soldering machine in China. It not only solves the problem that the conductive current electrode of the conductive electromagnetic pump is unstable due to the shielding of oxide slag, but also has no rotating parts, no converter, no maintenance, no wear, high efficiency, large and strong peak value and wide peak value.
The principle of three-phase asynchronous induction pump is to use the phase difference of three-phase power supply 120 to form their own magnetic fields. Synthetic magnetic field is a positive magnetic field that cuts magnetic lines, induces current and forms positive electromagnetic force.
Because the inherent phase difference of the three-phase power supply is directly used, the synthetic magnetic field basically has no pulsating magnetic field component, and it is a synthetic magnetic field that generates positive force, which is exactly the same as the principle of the electromagnetic gun, so the efficiency can reach more than 70%. Wave soldering machine composed of three-phase asynchronous induction electric pump has all the advantages of induction electromagnetic pump, such as superposition of audio disturbance vibration waves, enhanced welding ability and climbing ability, no rotating parts, no wear, no maintenance and simple structure.