Magnetron tube core for microwave heating

Abstract

The invention belongs to the field of magnetron design and production, and discloses a magnetron tube core for microwave heating. The magnetron tube core comprises a heated cathode emitter, an upper shielding cap, a lower shielding cap, a bimetal center support and upper electrode supply connecting rod, a side support and lower electrode supply connecting rod, a lower magnetic pole, a tube core casing and high-tension ceramic, wherein the upper shielding cap and the lower shielding cap are arranged on the heated cathode emitter; the bimetal center support and upper electrode supply connecting rod is welded by molybdenum as well as iron, nickel and cobalt constant-expansion ceramic sealing alloy; the side support and lower electrode supply connecting rod adopts iron, nickel and cobalt constant-expansion ceramic sealing alloy; and the high-tension ceramic is provided with sealing connection holes. According to the magnetron tube core for microwave heating, the iron, nickel and cobalt constant-expansion ceramic sealing alloy is adopted as lower half sections of the side support and lower electrode supply connecting rod and the center support and upper electrode supply connecting rod, a coefficient of linear expansion of the iron, nickel and cobalt constant-expansion ceramic sealing alloy is very similar to that of the high-tension ceramic, and the specific resistance of the iron, nickel and cobalt constant-expansion ceramic sealing alloy is far lower than that of molybdenum, so that the magnetron tube core has the characteristics of simple sealing structure and welding technology, good sealing performance, high reliability during working, long service life, high yield of production, lower cost and the like, and electrical performance of the cathode is improved to some extent.

Description

technical field [0001] The invention belongs to the technical field of magnetron design and production, and more specifically relates to the design and production of a magnetron core structure for microwave heating. The use of the magnetron core can prolong its service life and at the same time The production process is simplified and the production cost is reduced; the magnetron adopting the tube core is especially suitable as a microwave heating magnetron for a microwave high-temperature industrial kiln. Background technique [0002] The hot cathode is used as the electron emission source in the conventional microwave heating magnetron tube core, and current needs to be supplied to the hot cathode during operation to raise the temperature of the cathode to 1200°C to 2500°C. Since the magnetron is an electric vacuum device, it must work in a good vacuum environment, so the good sealing performance of the magnetron core is the key factor to ensure the performance and service...

AI Technical Summary

Problems solved by technology

When the magnetron is in good working condition, the temperature of the high-voltage ceramics 1-8 is generally about 120°C. Due to the large difference in expansion coefficient between the high-voltage ceramics 1-8 and metal molybdenum, the high-voltage ceramics 1-8 will A certain amount of stress is generated, especially in the intermittent operation due to the repeated stress of uneven expansion and contraction. This stress will affect the sealing performance of the brazing part of the high-voltage ceramics and metal molybdenum, as well as the metallized end leads of the high-voltage ceramics. To adverse effects, affecting its sealing and service life

This situation is particularly prominent in microwave high-temperature furnaces heated by magnetrons (in this environment, the temperature of high-voltage ceramics 1-8 in the magnetron can sometimes be as high as about 300 ° C), and the magnetron is more likely to be damaged; in addition , fully use metal molybdenum rods as the central support and the upper electrode power supply connecting rod and side support and the lower electrode power connecting rod, there are also resistivity (the resistivity of industrial pure polycrystalline molybdenum is 570μΩ·m) and high cost, and high voltage The sealing structure and welding process between ceramics are complicated, the yield rate in production is low, and the electrical performance of the cathode is also poor.

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