First, the load should be matched. No matter what equipment are required to do as much as possible to match the output load of the magnetron, that is, its voltage standing wave ratio should be as small as possible. Standing wave is not only a large reflected power, so that the actual power of the material being processed to reduce, and will cause the magnetron mode jump and cathode overheating, serious damage to the tube. Mode jumping, the anode current suddenly appears to fall. Causes of mode jumping in addition to the tube itself mode separation degree is small, there are mainly the following aspects: (1) power supply internal resistance is too large, high no-load and provoke non-π mode. (2) Serious load mismatch, the reflection of unfavorable phase weakens the interaction between the high-frequency field and the electron flow, and can not maintain the normal π mode oscillation. (3) Insufficient heating of the filament, causing insufficient emission, or insufficient emission due to cathode poisoning caused by outgassing in the tube, which cannot provide the tube current required for π-mode oscillation. In order to avoid the occurrence of mode jumping, it is required that the internal resistance of the power supply should not be too large, the load should be matched, and the filament heating current should meet the requirements of the manual.
Second, cooling. Cooling is to ensure that the magnetron normal tube work, one of the conditions, high-power magnetron anode commonly used water-cooled, the cathode filament lead part and the output ceramic window at the same time forced air-cooled, some solenoids are also air-cooled or water-cooled. Poor cooling will make the tube overheating and can not work properly, and in serious cases will burn the tube. It should be strictly prohibited to work under conditions of insufficient cooling.
Third, reasonable adjustment of cathode heating power. Magnetron vibration, due to unfavorable electronic bombardment back to the cathode so that the cathode temperature rises and is in a state of overheating, cathode overheating will make the material evaporation intensified, shortened life, serious cathode will burn. The way to prevent cathode overheating is to reduce the cathode heating power according to the specified adjustment.
Fourth, installation and commissioning. Currently commonly used microwave heating equipment magnetron on the excitation cavity directly stimulate the transmission system. Excitation cavity that is the energy excitation device, but also part of the transmission system. Therefore, the performance of the excitation cavity on the magnetron work has a great impact. The excitation cavity should be able to effectively transmit the microwave energy generated in the tube to the load. In order to achieve this purpose, in addition to the design of the excitation cavity itself, the assembly of the tube on the excitation cavity has a great impact on the stability of the work. Normal operation of the tube's anode and excitation cavity contact part of a large high-frequency current through the two must have good contact, poor contact will cause high-frequency firing. The depth of the antenna inserted into the excitation cavity directly affects the transmission of energy and the working state of the tube, should be carefully assembled according to the instructions.
Industrial microwave equipment are multiple tubes working at the same time! Equipment is well designed, there is no interference.
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