JPH0668784A - Voltage bushing - Google Patents

Abstract

PURPOSE: To facilitate manufacture and reduce the cost of a voltage bushing which is high in stability and insulating resistance by providing an insulating joint part of the vacuum electrical voltage bushing with a support body, provided with an enamel coating or a glass coating. CONSTITUTION: Voltage bushings 15, 16 are formed by applying an enamel coating or a glass coating to support bodies made of ceramic or plastic and inserted in hole parts 13, 14 of a first conductive member 2 and a second conductive member 3. The support bodies can be manufactured easily into sizes and shapes at a low cost using ceramic, plastic, or the like, and the support body is provided with desired vacuum airtightness, heat resistance and strength by applying an enamel coating or a glass coating to the whole or part of the support body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum electrical voltage bushing from a first conductive member through an enamel or glass insulating joint to a second conductive member.

[0002]

2. Description of the Related Art From DE-A-3912607, relatively durable vacuum-tight glass-metal joints or glass-metal joints using glass brazing are known. This joint is suitable for use in assembling a glass laser tube.

From EP-A-0048510 is known a CRT provided with a voltage bushing for a conductive pin. Here, the pin is guided by a support plate via an insulating joint and is held by the support plate. Further, the insulating portion is composed of a glass sealing portion, and the glass sealing portion is filled in the slit of the support plate. Similarly, insulative hermetic glass seals are known to insulate the electrodes from each other and maintain spacing.

European Patent Application No. 9110578
5.9 relates to the x-ray image amplifier. This image intensifier is used, for example, to form a visible image from an x-ray shadow image. Such an x-ray image amplifier has a substantially cylindrical vacuum container having an entrance fluorescent screen on one end face and an exit fluorescent screen on the other end face. An electrode is provided inside the vacuum container, and the electrode is held in the vacuum container by a holding element. A voltage is applied to the electrodes to focus the electrons formed on the entrance fluorescent screen during the generation of the x-ray beam onto the exit fluorescent screen. The voltage can be supplied to the electrodes via contact connection pins. The contact connecting pin is guided in a vacuum-tight manner through a vacuum container. It is known that the electrodes are connected to one another via an insulating material, whereby a stable electrode configuration is obtained in the vacuum vessel.

In x-ray image intensifiers, a bushing through the vacuum vessel of the contact-connecting pin or holding pin--if the valve of the vacuum vessel is made of glass--for example, a welded metal pin made of Vacon or another material that can be joined by glass It is known to make However, if the vacuum vessel is made of metal, the components are brazed or welded to the slits in the metal envelope of the vacuum vessel. Known components of this kind consist of an insulator (for example aluminum oxide Al ₂ O ₃ ) on which metal pins are brazed. Alternatively, the component comprises a weld flange for joining the metal overcoat on the insulator. Such a joint is vulnerable to airtightness because there are brazing points and welding points.

In order to avoid this drawback of the known braze and weld joints, European Patent Application No. 91105
In 785.93, an adhesive portion made of glass or enamel is provided. According to this, at least one conductive member is coated with a layer of enamel or glass, and the bonding of the conductive member is performed by supplying heat. That is, the covering portion is sealed under a predetermined condition and finally cooled. According to this proposal, enamel or glass is used as an insulating layer in the adhesive part in order to form a vacuum-tight and stable bond or bushing. Retaining energized contact connection pins on conductive components by enamel or glass sealing provides an improvement in vacuum tightness and mechanical stability over known ceramic bushings, but this type of The enamel or glass-sealed bushings have limitations in the size of the members to be joined and in the insulation resistance. Attempts to enlarge the components to be bonded with glass or enamel in order to increase the insulation resistance lead to stability problems during enamel application or bonding with glass or glass wax.

[0007]

SUMMARY OF THE INVENTION The object of the invention is to construct a voltage bushing of the type mentioned at the outset in such a way that it is easy to manufacture, has a high stability and a high dielectric strength and is relatively low in cost. .

[0008]

The above object is achieved according to the invention by constructing an insulating joint with a support having an enamel coating or a glass coating.

The voltage bushing according to the invention makes it possible to use supports made of, for example, ceramics, plastics, which can be manufactured simply and inexpensively according to size and shape. Therefore, this insulating member can be made of a relatively inexpensive material and can be enamel-coated or glass-coated in whole or in part if desired. Thereby the desired vacuum tightness is achieved. Advantageously, this imposes only low requirements on the support or the substrate in terms of porosity, surface properties and vacuum tightness. The support can be simply enamel-coated or glass-coated and has sufficient heat resistance for enamel-coating (enamel baking) or glass-coating to serve as a voltage bushing. It only has to have the required strength.

The advantages and features of the present invention will be apparent from the following description of the embodiments and the drawings. The same reference numbers are used in the figures for the corresponding parts.

[0011]

1 shows the basic construction of an x-ray image amplifier. This amplifier is provided with the voltage bushing of the present invention.

FIG. 1 shows a cross section of the x-ray amplifier 1. Here, the left side of the entrance fluorescent screen and the right side of the exit fluorescent screen of the x-ray image amplifier 1 are connected. The casing of the x-ray image intensifier 1 is a stand 1 as shown.
And the conductive members 2 and 3 of the base 2. This conductive member is formed of a thin belt as a cylinder. In the region 4, the end 5 of the first casing member 2 is joined to the end 7 of the second casing member 3 via the voltage bushing 6 according to the invention.

The x-ray image amplifier 1 is provided with first and second cylindrical electrodes 8 and 9. These electrodes are joined in the area 10 via a voltage insulation.

Conductive pins 11 to 12 are guided through the bushings 13 to 14 into the casing parts 2, 3 for the electrical contact connection of the electrodes 8, 9. Here, the bushings 13 and 14 are provided with the voltage bushings 15 to 16 of the present invention. The pins 11, 12 are also used for holding the electrodes 8, 9 in the x-ray image amplifier 1.
For that purpose, further pins 17, 18 are also provided. These pins are connected to the electrodes 8, 9 and the casings 2, 3 via further voltage bushings 19, 20.

The x-ray image amplifier 1 further comprises another electrode 21 with a terminal 22 to the high voltage source and a ground terminal 23. Here, a voltage bushing 24 is provided between the ground terminal 23 and the electrode. The enamel or glass covered support 25 of the voltage bushing comprises a winding 26 of resistance wire or the like and has adapter means 27, 28 connected to the resistance wire. The adapter means is in contact with the electrode 21 on the one hand and in conductive connection with the ground terminal 23 on the other hand. The electrode terminals 22 and 23 are voltage bushings 29,
Is insulated through the cylindrical casing part 3 by 30,
It is guided to the outside in a vacuum-tight manner.

The voltage bushing 33 shown in cross section in FIG.
In, the support 34 is made of a ring-shaped insulating member made of, for example, ceramic or plastic. In order to increase the insulation resistance and optionally the stability of the voltage bushing, the support can be configured as an insulating component of the desired size or the required size and shape. A complete vacuum coating or optionally a partial coating 35 of enamel or glass achieves the desired vacuum tightness of the insulation. Adhesion according to European Patent Application No. 91105785.9 has a limitation in the enamel technology or glass coating for insulation resistance and stability of the joint, using an enamel tube or a glass tube as the joint-insulator of two conductive members. Would not be a solution to the problem. On the other hand, the support 3
The use of 4 in connection with an enamel or glass coating provides a means of completely solving the above-mentioned problems.

The voltage bushing 33 of FIG. 2 is, for example, a bushing (for example, a hole) 13 of the first conductive members 2 to 3,
14 and the pins 11, 12 can be guided as second conductive members through the ring openings 36.
The glass or enamel layer 35 allows the pins 11, 12 to melt into the ring opening 16 and after subsequent cooling a strong bond of the pins 11, 12 to the support 34 is obtained. The support 34 can also be firmly melted into the bushings 13, 14 of the support members 2 to 3 by means of an enamel or glass layer. Members 2, 3 to 11, 1
A glass or enamel layer 35 is likewise used for the insulating vacuum-tight construction between the two and the support 34.

Particularly in voltage bushings with high voltages, a certain permissible current through the voltage insulation is often assumed. Often 100% insulation is not desired, especially for vacuum-tight voltage bushings. Full insulation can cause charging and high voltage flashover.

Thus, in the embodiment of the invention according to FIG. 7, the carrier 34 has a semiconductor layer 37, for example made of chrome oxide, on its enamel or glass layer 35. This layer 3
The desired conductivity is obtained by means of 7 through the insulating portion between the members 2 and 3.

As also shown schematically in FIG. 2, adapter means 38, such as adapter pins, adapter flanges, adapter tongues, etc., are inserted into support 34 and embedded, brazed paper, sintered, enamel. It can be coated or melted in with a glass wax.

In the voltage bushing 32 of FIG.
Inside, a winding made of a conductive material, a spring 39, etc. forms an electrical resistance, to which an adapter means 38, for example an adapter flange, provided on the end side of the support can be connected. In the exemplary embodiment, the adapter flange formed into the desired shape is interconnected with a spring 39 of resistance wire. The resistance wire is wrapped with a slight slope to avoid the individual turns from abutting each other.
The spring thus manufactured is in contact with the adapter flange. Further, an enamel or glass coating 35 is applied to the support body 34 formed of a spring by a coating method, a dipping method, a spray method, or a deposition method. The spring fitted in the support makes it possible on the one hand to obtain an insulating member with a relatively high strength and, on the other hand, to produce an insulator with a predetermined current value or electrical resistance value. The resistance value is determined by the spring material used, the wire thickness, the spring diameter, and the number of turns used. The voltage difference generated between the individual turns of the spring 39 can be kept relatively small. Therefore, a slight enamel or glass coating 35 provides good insulation. Considering the coefficient of expansion of the coating material and the desired conductivity of the voltage bushing, it is easy to harmonize between the selected coating material (enamel, glass), the resistance wire, the flange material and the structural size of the support. can get.
For the voltage bushing the support 34 is an adapter means 38
Together with this, a hollow cylinder can be formed in which, for example, contact connection pins can be accommodated.

FIG. 4 shows an embodiment of the voltage bushing 31 in which the support 34 of the spiral spring 40, which is wound at a slight interval of turns, consists of a resistance wire. The spiral spring has an enamel or glass coating 35, and the end of the spiral spring 40 is in contact with an adapter means, for example an adapter flange 38. This embodiment is suitable if the diameter of the voltage bushing is to be increased, if the electrical resistance of the voltage bushing is to be increased by means of a helical spring and / or if the strength or stability of the voltage bushing or the support 34 is to be improved.

In the embodiment of FIGS. 3 and 4, the turns of the resistance wire of the spring 39 or the spiral spring 40 are wound apart from one another at least at small intervals to avoid electrical bridging. The end of the resistor formed by spring 39 or spiral spring 40 may be welded or otherwise contacted in a suitable manner with the adapter means. The insulation or electrical resistance of the voltage bushings 31-33 is substantially determined by the structure of the support. That is, the material of the support, the material of the support spring or the support windings 39, 40, the length and thickness of the spring wire and the glass or enamel layer 3
It is defined by a thickness of 5. From there, the advantages of the voltage bushing are that the required stability can be met and the total resistance of the voltage bushing or the fine adjustment of the permissible current between the voltage bushing and the component to be joined.

FIG. 5 shows an embodiment of the voltage bushing 15. Here, in the hole 13 of the first conductive member 2,
A ceramic or plastic support 34 is fitted. In the embodiment, the pin 11 is configured as a second conductive member that is formed in a ring shape and passes through the support body provided with the flange 41. In the region of the hole 13, the conductive member 2 is covered with a glass or enamel coating 35. On the one hand, this covering is provided on the support 34
On the one hand, and on the other hand for the insulation and fixing to the conductive member 2 of the support. As shown in FIG. 5, the enamel or glass layer 35
Is likewise provided between the members 11 and 34 or between the members 2 and 34, 41. If the voltage bushing 15 should have the desired conductivity, the glass or enamel layer 35 between the conductive members 2 and 11 may be provided with a semiconductor coating 37, for example of chromium oxide.

In the embodiment of FIG. 8, the member 2 is provided with a stepped lower portion. A support 34 in the form of a tube embedded in enamel or glass is fitted in this lower part. The illustrated voltage bushing further has contact connection pins 11 as in FIG.

The voltage bushing 24 shown in detail in FIG.
Then, for example, it is possible to configure the adapter means 27 of the support 25 as the direct electrode 21 or to make direct contact with the electrode. Further, for example, the second adapter means 2
8 can be directly connected to an electrical component, for example a conductive line or a contact connection pin, as a voltage terminal or ground terminal.

The conductive members 2 and 3 shown only schematically in FIG.
The voltage bushing 6 between the electrodes 8 and 9 can, for example, consist of a ceramic or plastic carrier ring, at least on the inner surface of the ring and on the ring jacket (to the members 2, 3 to 8, 9 in the regions 4 to 10). Contact and joining surfaces) with an enamel or glass layer.

Voltage bushings according to claims 1 to 14 (with their connecting insulation by means of a support) because of their simple stability, simple and inexpensive manufacture and the good suitability of the voltage bushings to the desired insulation or resistance values. And enamel or glass coating) are particularly preferably applied to vacuum tubes or x-ray image intensifiers.

[0029]

According to the present invention, a voltage bushing which is easy to manufacture, has high stability and insulation resistance, and is relatively low in cost can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an x-ray amplifier provided with a voltage bushing of the present invention.

FIG. 2 is a schematic diagram of a first embodiment of the voltage bushing of the present invention.

FIG. 3 is a schematic diagram of a second embodiment of the voltage bushing of the present invention.

FIG. 4 is a schematic diagram of a third embodiment of the voltage bushing of the present invention.

FIG. 5 is a schematic diagram of a fourth embodiment of the voltage bushing of the present invention.

FIG. 6 is a schematic view of an example of an insulating portion of the present invention.

FIG. 7 is a schematic view of a waiting history example of the voltage insulating unit 33 of the present invention.

FIG. 8 is a schematic view of another embodiment of the voltage bushing of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 x-ray image amplifier, 2 1st conductive member, 3 2nd conductive member, 4 area | region, 5 End part of 1st member, 6
Voltage bushing, 7 end of second member, 8 first electrode, 9 second electrode, 10 region, 11 pin, 12 pin, 13 bushing, 14 bushing, 15, 16 voltage bushing, 17, 18
Pin, 19, 20 Voltage bushing, 21 Electrode

Claims (16)

[Claims] 1. A first conductive member (2, 8, 11, 17,
21, 22) to the second conductive member (3, 9, 12, 18, 23) via an insulating joint made of enamel or glass.
Vacuum electrical voltage bushings to (6, 15, 16, 1
9, 20, 24, 29, 30-33), wherein the insulating joint is provided with a support (34) with an enamel coating or a glass coating (35). 2. The voltage bushing according to claim 1, wherein the support (34) is completely covered by an enamel layer or a glass layer (35). 3. The support (34) can be enamel coated, enamelled or glass coated (3).
5) made of a material having heat resistance to the conductive material (2, 3, 8, 9, 11, 12, 17, 18, 2).
The voltage bushing according to claim 1, which has sufficient mechanical strength to bond 1 to 23). 4. The voltage bushing according to claim 3, wherein the support (34) is made of ceramic. 5. The voltage bushing according to claim 3, wherein the support (34) is made of plastic. 6. The support (34) comprises adapter means (38) such as adapter pins, adapter flanges, adapter tongues and the like.
The voltage bushing according to claim 1, further comprising: 7. Adapter means (38) for a support (34)
7. The voltage bushing according to claim 6, which is welded by insertion, fitting, brazing, sintering, enamel coating or glass brazing. 8. The voltage bushing according to claim 1, wherein the support (34) has a semiconductor coating (37) on the enamel or glass layer (35). 9. The voltage bushing according to claim 8, wherein the semiconductor coating (37) consists of chromium oxide. 10. The voltage bushing according to claim 1, wherein a winding, a spring or the like made of a conductive material forms an electric resistance in the support body (34) and is connectable to the adapter means (38). 11. The support (34) is a winding (3) of conductive material.
9, 40), said winding having an enamel or glass layer (35) for stabilization and vacuum tightness, with adapter means (38) provided on the end side of the winding. The voltage bushing according to claim 10. 12. A voltage bushing according to claim 10, wherein the windings (39, 40) consist of resistive wires. 13. At least one adapter means (2
Voltage bushing according to claim 10, wherein 7) is configured as an electrode (21). 14. At least one adapter means (2
8. The device according to claim 1, wherein 8) is embodied as a conductive pin (23).
0 voltage bushing. 15. The insulating joint having a support and an enamel layer or a glass layer is used for a vacuum tube.
The voltage bushing according to any one of 4 to 4. 16. The voltage bushing according to claim 1, wherein the insulating junction having a support and an enamel layer or a glass layer is used in an x-ray image amplifier.