JPH06176701A - Magnetron - Google Patents

Abstract

PURPOSE: To provide a shield of high level for preventing the emission of the electromagnetic radiation by surrounding an output prove by a shield structure, and locating the same in a magnetic field of a Faraday cage having a vacuum vessel and a pair of polarities. CONSTITUTION: A cylindrical anode block having a resonance cavity, a coil 8 and the like of a vacuum vessel of a magnetron, is mounted in an internal cavity 2 of the vacuum vessel. A long pin 9 of an output prove is surrounded by a sleeve 23 forming a shield structure 15, and the first and second tubes 16, 17 which are separated from each other, to prevent the electromagnetic radiation from a pin 5. Further the vacuum vessel is installed between a pair of magnetic poles of a Faraday cage of a sealed metallic container, and the electromagnetic radiation is shielded through the vacuum vessel. Thereby the magnetron having the shield of high level, which can prevent the emission of the electromagnetic radiation, can be obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to magnetrons, and more particularly, in at least one aspect, to magnetrons having a high level of shielding that prevent the emission of electromagnetic radiation.

[0002]

SUMMARY OF THE INVENTION The invention, in one aspect, is an anode having a plurality of internal resonant cavities, a cathode located within the anode, and an output probe for a vacuum vessel extending outwardly from the anode. A magnetron having the above-mentioned vacuum container, wherein the vacuum container is located in a magnetic field formed between a pair of magnetic poles, the magnetic poles being attached to opposite wall surfaces of a metal housing, Output probe of the invention provides a magnetron extending through an opening in the housing that serves to provide both a yoke for the poles and a Faraday cage to prevent unwanted emission of electromagnetic radiation from the magnetron.

In one preferred aspect, the present invention provides an electromagnet in the housing by a coil surrounding each magnetic pole, each coil being surrounded by an enclosure, and the electrical conductors being in respective enclosures of the housing. Extending to and from each coil through the wall of the housing in which power is supplied to the coils, whereby electromagnetic radiation is induced in the coils and from the conductors. Prevents radiation.

The above housing is bent into a U-shape,
It may be constituted by two flat metal plates having vertical rims which are overlapped with each other to form the four wall surfaces of the housing, and the other two wall surfaces are constituted by grids each having an aperture. it can. The container is preferably removable from the metal housing to allow the vacuum container to be replaced without the expense of replacing the metal housing and the magnetic poles. High power magnetron,
That is, in a magnetron having a power output exceeding about 5 KW, this is a great advantage because the magnetic pole and the metal housing are relatively large, and the manufacturing cost is high, especially when the This is because the manufacturing cost is high when the high frequency shield is built in.

In another aspect, the invention provides a method of assembling a magnetron comprised of an anode having a plurality of internal resonant cavities, the method comprising inserting an elongated cathode in the center of the anode. An end cap is secured to one end of the cathode, the end cap having a first hole extending across the end cap and extending to the longitudinal axis of the cathode; The end away from the cathode
Having the above steps extending between the surface of the cap and the interior of the first hole, the method provides a long conductor operable in the assembled magnetron of the first hole. Providing support means for the cathode and means for supplying current to the cathode, welding, brazing, or similar tool positioned within the second hole, and The method further includes operating a tool to electrically and mechanically connect the elongated conductor to the end cap.

It has been found that the assembly method as described above is reliable and efficient. In a preferred aspect, the above steps are repeated to secure another elongated conductor to the other end of the cathode. The above cap has an insertion part,
The cathode may have a spiral coil, and the method includes the step of welding, brazing or otherwise electrically and mechanically connecting the insert to the open end of the coil. .

In yet another aspect, the present invention provides a magnetron comprised of an anode having a plurality of internal resonant cavities and a cathode supported within the anode by support means extending outwardly from the anode. The supporting means is composed of a long conductor insulated from the anode and supplying a current to the cathode, and the conductor prevents emission of electromagnetic radiation from the conductor. To this end, the shield is surrounded by a shield, and the shield is constituted by a first tube that surrounds the elongated portion of the conductor and that is radially spaced from the elongated portion, and the length of the first tube is Is substantially equal to 1/4 of the wavelength of the output signal of the magnetron, the first tube being electrically connected to the anode, Gunetoron the first tube and the length and diameter are substantially equal, it surrounds the other elongated portion of the conductor, the second with a spacing radially from the long arm member
A second tube, wherein the first tube and the second tube are axially separated from each other, and the second tube is electrically connected to the cathode,
And a larger diameter than the first and second tubes, radially spaced from the first and second tubes, and an axial separation between the first and second tubes. Constituted by a third tube extending across.

It has been found that such a shield structure unexpectedly provides a very high degree of electromagnetic shielding. The third tube is preferably connected to the anode.
In one preferred aspect, the first tube is secured within a wall of an opening extending through the anode, the third tube is substantially equal in length to the first tube, and Is fixed in the wall surface of a stepped recess surrounding the opening provided in the anode.

A terminal is connected to the free end of the elongated conductor and a sleeve of insulating material extends between the terminal and the anode.

[0010]

For a better understanding of the present invention, one embodiment is illustrated by way of example with reference to the accompanying drawings. The vacuum vessel for a magnetron shown in FIGS. 1 and 2 has a generally cylindrical anode block 1 with an internal cavity 2 open at one end.
Composed by. A plurality of circumferentially spaced anode vanes 3 extend into the central region of the cavity 2 and form a plurality of resonant cavities 4. Police box vane 3
Are strapped together at each end by one of a pair of rings 5, 6 in a known manner.

Each of these vanes 3 stops without reaching the center of the cavity 2 to form a cylindrical space 7, and a cathode constituted by a thorium-tungsten coil 8 is arranged in this space. . A long conducting pin 9 is attached to each end of the coil 8 and supplies current to the cathode. Each conducting pin 9 extends out through an opening 10 in the anode block 1. Each conducting pin 9 has a coil 8 with a hat-shaped end cap 11 on the top.
Connected to the end cap 11 is an annular rim 1.
2 and insert 13, which is brazed or welded into the open end near the coil 8. The end cap 11 has a first hole 11a extending from one edge into the rim 12 of the end cap 11. The second hole 14 extends between the surface 12 a away from the cathode and the first hole, and penetrates the insertion portion 13. During assembly, the constant length portion 9a of the conductor is inserted into the first hole 11a and a welding, brazing or similar tool is introduced into the second hole at a predetermined position to bring the conductor 9 into the cap 11 and thus the coil. 8 electrically and mechanically. Such an assembly method has proven to be reliable and convenient.

The elongated conducting pin 9 is configured to both supply current to the cathode and to provide a means for supporting the cathode in spaced relation to the anode. The portion of pin 9 that extends outwardly from the anode block is surrounded by a choke or shield structure 15 and is configured to limit the emission of electromagnetic radiation coupled to this conductor from the resonant cavity of the magnetron. The shield structure 15 is constituted by a first tube 16 extending outward from the wall surface of the opening 10 in the anode block. The first tube 16 is
It surrounds the fixed length part of the pin 9 and at the same time has a space in the radial direction,
It has a length substantially equal to 4. A second tube 17 of substantially the same length and diameter as the first tube surrounds the other constant length portion of the conducting pin 9. A small axial gap 18 separates the two tubes 16 and 17 so that they are electrically isolated from each other. The end portion of the tube 17 on the side far from the axial gap 18 is fixed to an electric terminal 19 attached to the conduction pin 9. Although the first tube and the second tube have substantially the same length,
Another tube 20 of relatively large diameter is fixed in a stepped recess 21 in the side wall of the hole 10 in the anode block 1. The third tube 20 encloses most of the length of the first tube 16, which extends across the axial gap 18 and encloses a short longitudinal section of the second tube 17. The third tube 20 has a flange 22 extending outward. Sleeve 23 formed of an insulating material such as ceramic
Is the other three rings 24 made of insulating material.
Together, it extends between the terminal 19 and the anode block. It has been found that the shield structure 15 described above unexpectedly provides a very high degree of electromagnetic shielding.

The vacuum vessel has an output probe 25 extending from one of the vanes. A pair of ring-shaped channels 26, 27 extend centered around the anode block 1 in coaxial relationship with its main axis. The two channels 26, 27 are spaced by a partition 28. A cylindrical sleeve 30 surrounds the anode block 1 and has suitable openings for receiving the shield structure 15 and the output probe 25. Wall 2 dividing these two channels 26, 27
8 is a connecting passage 30 that stops in the immediate vicinity of the cylindrical sleeve 30 and has a greatly reduced cross-sectional area with respect to the channels 26, 27.
To provide. A coolant inlet 31 and an outlet 32 extend into one corresponding to these two channels 26, 27 respectively. When used, the coolant flows around one channel, through the communication passage 30 around the other channel and then to the outlet. Such a configuration is relatively easy to provide on the anode block and provides efficient cooling. A pair of end plates 34 are provided at each end of the anode block to seal each end of the cavity 2,
As a result, the inside can be evacuated. As explained below, the output probe 25 has a peripheral flange 35 for removably mounting the vacuum vessel within its housing.

FIGS. 3 and 4 show the container just described with reference to FIGS. 1 and 2, which is located in a box-shaped housing 40, which serves as a Faraday cage and which is removed from the magnetron. Prevent the emission of electromagnetic radiation. The housing 40 is composed of two flat metal plates 41 and 42, and these metal plates are bent to have a U-shape when viewed in cross section. Next, these two metal plates are configured so that the rims extending above the two housing members 41, 42 overlap each other. On the other two sides of this housing, an apertured grid 44
To provide. An electrical cable 58 is connected to the magnetron terminal 16 via a cylindrical insulating sleeve 59 to supply current to the cathode coil 8.

A magnetic field is applied to the magnetron by the pair of magnetic poles 45 and 46, and the magnetic poles are made of a ferromagnetic material and fixed to the opposite wall surfaces of the housing. In this way, the yoke for the magnetic circuit is provided by the housing 40. Lines 48, 49
Coil surrounds each magnetic pole 45, 46. Coil 4
8, 49 operate as a Helmholtz coil pair and generate other magnetic fields for controlling the power output of the magnetron in a generally known manner. Cylindrical enclosure 5
0 and 51 surround each coil 48 and 49, respectively.
Each enclosure 50, 51 is configured to prevent electromagnetic energy from the magnetron from being induced in each of the respective coils 48, 49. There are openings 52 and 53 in each enclosure and each magnetic pole 4
Accept one of 5,46. Terminal block 54, 55
Are provided on the outside of the housing adjacent one of the respective coils 48, 49. The terminal blocks 54 and 55 are
Each has an electrical conductor 56 which extends through the wall of the housing where it is connected to their respective coil. A bolt 56 extends through the wall 42 of the housing and the flange 35 of the vacuum vessel to removably mount the vessel within the housing.

[0016]

Since these conductors extend into the coil within the enclosure, little electromagnetic energy is induced in the coil from the magnetron and the conductor 56 or any lead 56 connected thereto (see FIG. Almost no emission from (not shown). Further, the container can be easily removed from the housing, so that maintenance costs in the event of failure of the container are reduced compared to when constructed integrally with the poles. This means that if the magnetron has a high power output, that is, if the power output exceeds about 5 kW, and the need for size and high level shielding, the high frequency enclosure provided by the housing, combined with the magnetic poles and coils, will be manufactured. It is particularly advantageous when it means that the item is an overpriced item.

[Brief description of drawings]

FIG. 1 is a side view of one side of a vacuum container for a magnetron, with an end plate removed to show the inside of the container.

FIG. 2 is a sectional view taken along line AA shown in FIG.

FIG. 3 is a cross-sectional view of the housing and magnet assembly,
Located therein is the vacuum vessel of FIGS. 1 and 2, which is not shown in cross section in this figure.

FIG. 4 is a view seen from a direction of an arrow B shown in FIG.

[Explanation of symbols]

 1 Cylindrical Anode Block 2 Internal Cavity 3 Anode Vane 4 Resonant Cavity 8, 48, 49 Coil 11 Cap 11a First Hole 13 Insertion Part 14 Second Hole 15 Shield Structure 16 First Tube 17 Second Tube 18 Axial Direction Gap 20 Third tube 25 Output probe 26, 27 Channel 30 Connection passage 35 Flange 40 Faraday box 45, 56 Magnetic pole

[Procedure amendment]

[Submission date] November 29, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (12)

[Claims] 1. A magnetron having a vacuum vessel constituted by an anode having a plurality of internal resonant cavities, a cathode located within the anode, and an output probe of the vacuum vessel extending outwardly from the anode: The vacuum vessel is located in a magnetic field formed between a pair of magnetic poles; the magnetic poles are attached to opposite wall surfaces of a metal housing; the output probe is a yoke of the magnetic poles and the magnetic poles. A magnetron extending through the opening in the housing which serves to provide both of the Faraday cages which prevent the emission of undesired electromagnetic radiation from the magnetron; 2. A coil surrounds each magnetic pole to provide an electromagnet within the housing, each coil being surrounded by an enclosure, and a conductor defining a wall of the housing within each enclosure of the housing. To extend to and from each coil to supply power to the coils, thereby preventing electromagnetic radiation from being induced in the coils and radiated from the conductors. Claim 1 characterized by
The described magnetron. 3. The magnetron according to claim 1, wherein the vacuum container is removable from the metal housing and the magnetic pole. 4. The housing is composed of two flat metal plates bent into a U shape and having vertical rims that overlap each other to form the four walls of the housing. 4. The magnetron according to claim 1, wherein the other wall surface of the magnetron is constituted by a lattice having apertures. 5. A method of assembling a magnetron constituted by an anode having a plurality of internal resonant cavities: the method comprising: inserting an elongated cathode in the center of the anode, the end cap Fixed to one end of the cathode, the end cap having a first hole extending across the end cap and longitudinally of the cathode, the second hole being spaced apart from the cathode. The step of extending between the surface of the end cap of the first end and the interior of the first hole, the method including a long conductor operable in the assembled magnetron. Inserting into one hole a support means for said cathode and means for supplying a current to said cathode, inserting said conductor into said first hole From,
Positioning a welding, brazing, or similar tool in the second hole, and operating the tool to electrically and mechanically connect the elongated conductor to the end cap. The method further comprising the step of: 6. The method according to claim 5, wherein the above steps are repeated to fix another elongated conductor to the other end of the cathode. 7. The end cap has a bayonet and the cathode has a helical coil, the method comprising welding the bayonet into the open end of the coil. 7. A method as claimed in claim 5 or 6, characterized in that it is constituted by the step of electrically and mechanically connecting in another way. 8. A method of assembling a magnetron substantially as described with reference to either FIG. 1 or FIG. 9. A magnetron comprising an anode having a plurality of internal resonant cavities and a cathode supported within said anode by support means extending outwardly from said anode: said support means comprising: Of an elongated conductor that is insulated from the anode and supplies current to the cathode; the conductor is surrounded by a shield to prevent electromagnetic radiation from being emitted from the conductor; The shield above is
It is constituted by a first tube that surrounds the elongated portion of the conductor and is spaced from the elongated portion in the radial direction, and the length of the first tube is substantially equal to the wavelength of the output signal of the magnetron. Equal to 1/4, the first tube being electrically connected to the anode; the magnetron being: the first tube being substantially equal in length and diameter to the first tube;
A second tube surrounding another elongated portion of the conductor and having a radial spacing from the elongated portion, wherein the first tube and the second tube are axially separated from each other,
The second tube has a larger diameter than the second tube electrically connected to the cathode; and the first and second tubes, and the second tube is radially connected to the first tube and the second tube. A third tube having a spacing and extending across the axial separation between the first tube and the second tube; 10. The magnetron according to claim 9, wherein the third tube is connected to the anode. 11. The first tube is secured within a wall of an opening extending through the anode block,
The third tube has a length substantially equal to that of the first tube, and is fixed in a wall surface of a stepped recess surrounding an opening provided in the anode block. Item 9. The magnetron according to Item 9 or 10. 12. A terminal is connected to the free end of said elongated conductor and a sleeve formed of an insulating material extends between said terminal and said anode block. The magnetron according to either 10 or 11.