阅读说明：本技术 一种2450MHz大功率微波烧结熔炼用真空密封窗 (Vacuum sealing window for 2450MHz high-power microwave sintering and smelting ) 是由 郑强林 闫二艳 杨浩 陈世韬 鲍向阳 于 2021-06-21 设计创作，主要内容包括：本发明公开了一种2450MHz大功率微波烧结熔炼用真空密封窗,包括位于真空端的第一波导和位于馈入端的第二波导,以及位于第一波导和第二波导之间的介质窗；微波在介质窗中传播形成的波峰处于介质窗外。采用本发明的一种2450MHz大功率微波烧结熔炼用真空密封窗,在微波熔炼金属材料时,保证微波能量馈入至真空熔炼炉中,不会在密封窗处打火烧蚀。(The invention discloses a 2450MHz high-power microwave sintering and smelting vacuum sealing window, which comprises a first waveguide positioned at a vacuum end, a second waveguide positioned at a feed-in end and a dielectric window positioned between the first waveguide and the second waveguide; the wave crest formed by the microwave propagating in the dielectric window is positioned outside the dielectric window. By adopting the 2450MHz high-power vacuum sealing window for microwave sintering and smelting, when metal materials are smelted by microwave, microwave energy is fed into a vacuum smelting furnace, and the sealing window is prevented from being ignited and ablated.)

1. A2450 MHz high-power microwave sintering and smelting vacuum seal window is characterized in that: the waveguide comprises a first waveguide positioned at a vacuum end, a second waveguide positioned at a feed end and a dielectric window positioned between the first waveguide and the second waveguide;

the thickness of the dielectric window is half wavelength or integral multiple of half wavelength of microwave propagating in the dielectric window.

2. The 2450MHz high-power microwave sintering and smelting vacuum seal window of claim 1, wherein: the first waveguide and the second waveguide are provided with flange plates and fixedly connected through bolts.

3. The 2450MHz high-power microwave sintering and smelting vacuum seal window of claim 1, wherein: the first waveguide and the second waveguide are BY22 circular waveguides.

4. The 2450MHz high-power microwave sintering and smelting vacuum seal window of claim 1, wherein: the first waveguide is provided with a sealing groove, and a sealing ring is arranged in the sealing groove.

5. The 2450MHz high-power microwave sintering and smelting vacuum seal window of claim 1, wherein: and simulating and calculating the wave crest and the wave trough formed by the propagation of the microwave in the dielectric window through electromagnetic simulation software, so that the dielectric window is positioned outside a strong field region of the microwave.

6. The 2450MHz high-power microwave sintering and smelting vacuum seal window of claim 4, wherein: the thickness of the dielectric window is half wavelength of microwave propagating in the dielectric window.

7. The 2450MHz high-power microwave sintering and smelting vacuum seal window of claim 1, wherein: the dielectric window is a ceramic dielectric window, and the dielectric constant is 9.9.

8. The 2450MHz high-power microwave sintering and smelting vacuum seal window of claim 7, wherein: the thickness of the dielectric window is 19.8 mm.

9. The 2450MHz high-power microwave sintering and smelting vacuum seal window of claim 1, wherein: the dielectric window is a Teflon dielectric window, and the dielectric constant is 2.1.

10. The 2450MHz high-power microwave sintering and smelting vacuum seal window of claim 9, wherein: the thickness of the dielectric window is 59 mm.

Technical Field

The invention relates to a 2450MHz high-power vacuum sealing window for microwave sintering and smelting, belonging to the technical field of microwave smelting.

Background

The traditional heating method is a method of transferring heat energy to an object to be heated by a heating body in a convection, conduction or radiation mode to enable the object to reach a certain temperature. Microwave sintering utilizes the special wave band of microwave to couple with the basic fine structure of material to generate heat, and the dielectric loss of material makes the whole material be heated to sintering temperature to implement densification method. Compared with conventional sintering, microwave sintering has the advantages of high temperature rise speed, high energy utilization rate, high heating efficiency, safety, sanitation and no pollution, and can improve the uniformity and yield of products. Because of the advantages of cleanness, high efficiency and convenient operation, the method is widely applied to the research fields of ceramic materials and metal materials.

In the microwave melting and sintering of metal materials, in order to avoid the oxidation of the metal materials caused by the contact of the metal materials and air, the metal materials are mostly finished under the vacuum condition, and a vacuum sealing window is an indispensable component.

A microwave melting apparatus such as that of chinese patent application 2021105687509 requires the use of a vacuum sealed window.

The conventional 2450MHz microwave source is low in power and about 1kW in output power, a medium window is not adopted if the system does not have a vacuum requirement, and if the medium window is required to be adopted by the system according to the vacuum requirement, the microwave can be ensured to pass through according to theoretical calculation by adopting materials such as ceramic and beryllium oxide, but only a small amount of heat can be generated at the medium window due to the low power (the generated heat is limited and is treated by adopting a thermal design means) without ignition and ablation.

The high-power 2450MHz microwave source for smelting has high output power (average power is more than 10kW), so that more heat is generated at a dielectric window, a strong field region appears in the waveguide feeder line transmission process, and the higher the output power is, the stronger the field strength is. If the design is not proper, heat can be rapidly generated due to dielectric loss of the dielectric material, and the window slice is ablated and ignited due to temperature rise, so that the sealing window is damaged.

Disclosure of Invention

The invention aims to: aiming at the problems, the invention provides the 2450MHz high-power vacuum sealing window for microwave sintering and smelting, which ensures that microwave energy is fed into a vacuum smelting furnace and the sealing window is not ignited and ablated when a metal material is smelted by microwave.

The technical scheme adopted by the invention is as follows:

a2450 MHz high-power microwave sintering vacuum sealing window for smelting comprises a first waveguide at a vacuum end, a second waveguide at a feed-in end, and a dielectric window between the first waveguide and the second waveguide;

the thickness of the dielectric window is half wavelength or integral multiple of half wavelength of microwave propagating in the dielectric window.

When the microwave smelting device is used, the first waveguide is connected with the vacuum smelting device, the second waveguide is communicated with the microwave source, 2450MHz high-power (more than 10kW) microwaves enter the vacuum smelting device from the second waveguide through the dielectric window for microwave smelting, the microwaves are propagated in the dielectric window and can periodically form wave crests and wave troughs, wherein the maximum field intensity of wave crest energy is maximum, and a strong field region is formed near the wave crests. By setting the thickness of the dielectric window to be half wavelength or integral multiple of half wavelength of microwave transmitted in the dielectric window, wave peaks formed by the transmission of the microwave in the dielectric window can be positioned outside the dielectric window, and the dielectric window is positioned outside a strong field region, so that the microwave can not generate a large amount of heat on the dielectric window to cause ablation and ignition to damage the dielectric window.

It should be noted that the thickness of the dielectric window is very critical, and a too low thickness of the dielectric window will cause the dielectric window to fall within the strong field region, while a too high thickness of the dielectric window will also cause the dielectric window to fall within the strong field region. Through simulation calculation, when the thickness of the dielectric window is half wavelength or integral multiple of half wavelength of microwave transmitted in the dielectric window, wave crests formed by the microwave transmitted in the dielectric window are positioned outside the dielectric window, and the dielectric window is positioned outside a strong field area of the microwave, so that the sealing window cannot be ignited and ablated.

Preferably, the first waveguide and the second waveguide are provided with flanges, and the first waveguide and the second waveguide are fixedly connected through bolts.

In the scheme, the first waveguide and the second waveguide are fixed through the flange simply and conveniently.

Preferably, the first waveguide and the second waveguide are BY22 circular waveguides.

In the scheme, the larger the size of the waveguide is, the larger the power capacity is, and the BY22b is the largest standard circular waveguide capable of transmitting a 2450MHz microwave single mode, so that the power capacity is maximized.

Preferably, the first waveguide is provided with a sealing groove, and a sealing ring is arranged in the sealing groove.

Preferably, the sealing ring protrudes 2mm from the sealing window.

In the above scheme, the sealing effect is increased by arranging the sealing ring and the sealing groove, and the vacuum degree of the vacuum smelting device is ensured.

Preferably, the wave crest and the wave trough formed by the propagation of the microwave in the dielectric window are simulated and calculated through electromagnetic simulation software, so that the dielectric window is positioned outside a strong field region of the microwave, and the position of the maximum field intensity of the microwave is monitored at any time.

In the above scheme, the dielectric constant, the dimensional structure and the microwave frequency of the dielectric window have a corresponding relationship, a professional simulation software is required to be used for simulation design, Ansoft, HFSS or CST electromagnetic simulation software is used for simulation calculation through the microwave frequency and the dielectric constant of the dielectric window, the thickness of the dielectric window is designed, the dielectric window is located outside a strong field region of microwaves, the optimal thickness of the dielectric window is obtained by setting an initial value and continuously optimizing calculation during simulation design, the thickness of the dielectric window is obtained and is an integral multiple of half-wavelength or half-wavelength of the microwaves transmitted in the dielectric window, wave peaks formed by the microwaves transmitted in the dielectric window can be located outside the dielectric window, and the dielectric window is located outside the strong field region, so that the microwaves cannot generate a large amount of heat in the dielectric window to cause ablation and ignition to damage the dielectric window.

Preferably, the thickness of the dielectric window is half the wavelength of the microwave propagating in the dielectric window.

In the above scheme, the thicker the dielectric window is, the greater the microwave loss is, so that the thickness of the dielectric window is half the wavelength of the microwave propagating in the dielectric window, which can simultaneously achieve both loss and ablation avoidance.

Preferably, the dielectric window is a ceramic dielectric window, and the dielectric constant is 9.9.

In the scheme, the ceramic dielectric window can enable microwaves to pass through the dielectric window with low loss.

Preferably, the dielectric window has a thickness of 19.8mm and a diameter of 129.5 mm.

In the above scheme, through simulation design of simulation software and parameter setting, the dielectric window is far away from the microwave high field range after the microwave passes through the dielectric window, and the dielectric window is prevented from falling into the high field range to cause fire and ablation of the dielectric window.

Preferably, the dielectric window is a teflon dielectric window, and the dielectric constant is 2.1.

In the scheme, the Teflon dielectric window can enable microwaves to pass through the dielectric window with low loss.

Preferably, the dielectric window has a thickness of 59mm and a diameter of 129.5 mm.

In the above scheme, through simulation design of simulation software and parameter setting, the dielectric window is far away from the microwave high field range after the microwave passes through the dielectric window, and the dielectric window is prevented from falling into the high field range to cause fire and ablation of the dielectric window.

According to the 2450MHz high-power vacuum sealing window for microwave sintering and smelting, the dielectric window is made to be outside the high-field range of microwave by selecting a proper dielectric window material and designing a proper dielectric window thickness through simulation software, so that ignition and ablation at the sealing window are avoided.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that: low loss of microwave energy through the dielectric window; and strong fields cannot be formed at the dielectric window to cause the dielectric window to be ignited and ablated.

Drawings

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

fig. 1 is a schematic view of the structure of a vacuum sealing window.

The labels in the figure are: 1-first waveguide, 2-second waveguide, 3-dielectric window, 4-flange, 5-sealing groove and 6-sealing ring

Detailed Description

All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.

Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

Example 1

As shown in fig. 1, the 2450MHz high-power microwave sintering melting vacuum sealing window of the present embodiment includes a first waveguide at a vacuum end, a second waveguide at a feed end, and a dielectric window between the first waveguide and the second waveguide;

the first waveguide and the second waveguide are BY22 circular waveguides with flanges and fixedly connected with each other through bolts;

the first waveguide is provided with a sealing groove, a sealing ring is arranged in the sealing groove, and the sealing ring protrudes out of the sealing window by2 mm;

wherein the dielectric window is a ceramic dielectric window, the dielectric constant is 9.9, the thickness is 19.8mm, and the diameter is 129.5 mm.

Example 2

As shown in fig. 1, the 2450MHz high-power microwave sintering melting vacuum sealing window of the present embodiment includes a first waveguide at a vacuum end, a second waveguide at a feed end, and a dielectric window between the first waveguide and the second waveguide;

the first waveguide and the second waveguide are BY22 circular waveguides with flanges and fixedly connected with each other through bolts;

the first waveguide is provided with a sealing groove, a sealing ring is arranged in the sealing groove, and the sealing ring protrudes out of the sealing window by2 mm;

wherein the dielectric window is a Teflon dielectric window, the dielectric constant is 2.1, the thickness is 59mm, and the diameter is 129.5 mm.

As other alternatives to the above embodiment, in other embodiments, the thickness of the dielectric window may be increased by an integral multiple.

In the embodiment, when the microwave smelting device is used, the first waveguide is connected with the vacuum smelting device, the second waveguide is communicated with the microwave source, and 2450MHz high-power (more than 10kW) microwaves enter the vacuum smelting device from the second waveguide through the dielectric window to carry out microwave smelting. The proper thickness of the dielectric window is obtained through simulation design, microwaves can pass through the sealing window in low loss, and a strong field area formed after 2450MHz microwaves pass through the dielectric window is positioned outside the dielectric window, so that the situation that the microwaves rapidly generate heat through the dielectric window due to improper design and a window piece is ignited and ablated due to temperature rise is avoided.

The microwave smelting device of the similar patent application 2021105687509 is applied to the embodiment 1 or the embodiment 2, the power of a microwave source of 2450MHz is 10kW, and the field intensity simulation at a dielectric window is about 2.5V/cm; placing a recrystallized silicon carbide crucible in a smelting furnace, filling copper scraps in the crucible, monitoring the temperature of silicon carbide by an armored temperature sensor, monitoring the surface temperature of a microwave Teflon sealing window by an infrared thermal imager, keeping the air pressure in the vacuum smelting furnace at 10-3pa, and effectively preventing the medium window from being ignited and ablated when the temperature of the silicon carbide is increased to 1200 ℃.

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.