EP0020253B1 - Insulated collector for an electronic power tube - Google Patents

Description

The subject of the invention is an insulated collector for an electronic power tube and a tube equipped with such a collector.

It is known that the collectors of electronic tubes must be brought to high potentials in absolute value, in order to receive at the end of their journey the electrons of the beam.

The problem therefore arises on the one hand to cool this collector, and on the other hand, for safety reasons, its electrical insulation.

However, electrical isolation can only be done by means of insulating parts, for example ceramic parts, while the heat radiating devices are generally metallic. We are therefore led to interpose between the collector itself and the radiator, pieces of ceramic or other insulators. The assembly is therefore composed of materials which do not have the same coefficients of thermal expansion, which poses problems of mechanical stresses during operation.

Such a collector is described in U.S. Patent 3,717,787. This collector comprises a live part, intended to receive the electrons having yielded part of their kinetic energy to a traveling wave, an insulating tube surrounding said part and an external envelope connected to a cold source. A heat conducting assembly, made up of elastic parts which can deform both along the axis of the collector and along its straight sections, connects the insulating tube to the envelope, the parts being respectively anchored on the external surface of the insulating tube and on the inner surface of the envelope. Between the live part and the insulating tube is interposed a flexible sleeve, also conductive of heat and fixed by two-component cex brazing, which is provided with stamped projections which establish contact with the internal surface of the insulating tube.

The present invention relates to an electron collector assembly and its cooling device, in which these stress problems are avoided.

The insulated collector for power tube according to the invention is of the type comprising two sets of heat-conducting elastic connecting means, the first connecting the under-tensioned part of the collector to an insulating part, the second connecting the insulating part to the radiator, the elastic connection means being constituted by elements or parts of elastic elements situated in planes of cross section and successive along the axis. They are characterized and that either the elements or parts of elements conforming so as to be able to deform axially comprise alternately and on each side, point protruding parts by which they are fixed on the parts between which they are placed so as also to allow their bending in a plane parallel to the axis or else the elements or parts of elements shaped so as to be able to deform axially have first protruding parts and on either side of the second parts respectively corresponding , the parts of one of the assemblies being punctual, parts by which they are fixed on the parts between which they are placed so as to also allow their bending in a plane parallel to the axis.

• - la figure 1 est une vue schématique en coupe longitudinale du dispositif selon l'invention;
• - les figures 2, 3, 4 représentent un premier exemple de réalisation des pièces élastiques;
• - la figure 5 représente vu de côté un deuxième exemple de réalisation;
• - les figures 6, 7 et 8 sont les vues partielles d'éléments composant l'ensemble de la figure 5;
• - les figures 9, 10 et 11 sont des vues de dessus des mêmes éléments;
• - la figure 12 est une vue en perspective et en arraché de l'ensemble de la figure 5.

The invention will be better understood by means of the description below with reference to the accompanying drawings, in which:

• - Figure 1 is a schematic view in longitudinal section of the device according to the invention;
• - Figures 2, 3, 4 show a first embodiment of the elastic parts;
• - Figure 5 shows a side view of a second embodiment;
• - Figures 6, 7 and 8 are partial views of elements making up the assembly of Figure 5;
• - Figures 9, 10 and 11 are top views of the same elements;
• FIG. 12 is a view in perspective and broken away of the assembly of FIG. 5.

In Figure 1, we see in 1, collector of a vacuum tube, for example a traveling wave tube. This collector comprises a copper enclosure in the form of a tube hollowed out in its central part, which has the shape of a cone of revolution around the axis of the tube, which is also the axis of the electron beam when the tube is in operation. .

A first elastic assembly 2 is brazed to the external surface of the tube, which will be described later. This assembly 2 is brazed on the internal part of a ceramic tube 3. The external face of this tube 3 is brazed to a second elastic assembly 4 which supports a piece of copper 5, which cools the collector. This device has as axis of revolution the axis of the collector.

It can therefore be seen that the radiator 5 is electrically disconnected from the collector 1 and can be grounded, whatever the potential of the collector.

This being so, we see that in operation, the collector 1 tends to heat up by absorption of the electrons. Its coefficient of thermal expansion is different from that of ceramic 3. It is the same for the radiator 5. The two assemblies 2 and 4, therefore have during operation to withstand the stresses which result therefrom.

The invention makes it possible to produce an assembly capable of withstanding these constraints.

Figure 2 and Figures 3 and 4 respectively represent a cross section, and partial views of a first embodiment of the first or second set.

In Figure 2, we see the assembly 2 seen in section. It is formed by two series of parts 10 and 11, which extend parallel to the axis of the collector.

All of the parts cover the internal face of the ceramic and the external face of the collector.

A part 10 is shown in FIG. 3. It comprises a backbone 12. This backbone carries bars 13 (thorn and bars can form a monobloc assembly or be assembled brazed). The backbone is brazed to the collector and the bars to the ceramic.

The part 11 comprises two identical side rails 15 5 and 16. Each of these beams is connected to the other by a set of spacers 17 separated from each other by so-called "flexibility" slots 18 which extend into the beams.

The assembly is elastic and can deform in length in the direction of the generator, or in compression in the plane of the cross section.

The parts 10 and 11 fit together as shown in Figure 2, the backbones and the side members 15 and 16 being brazed to the manifold.

The set 4 is similar to the set 2.

In Figure 4 is shown seen from the side another embodiment of the assembly 2. As in the previous case, the assembly 4 is similar to the assembly 2. But while one works in compression, the other works and extension and vice versa.

The assembly 2 is composed of flexible mechanical elements 20 extending essentially in the cross-sectional planes of the cylinder which forms the external surface of the manifold 1. Each element comprises a succession of fasteners brazed alternately at points 21 on the manifold 1 and at points 22 on ceramic 3, the whole forming a broken line. These elements are arched as shown in FIG. 5 in a first direction for the elements 30, and in the opposite direction for the elements 31. The plane 100 is substantially the median plane of the collector. This arrangement halves the longitudinal deformations of the elements.

FIG. 7 likewise represents an element of the assembly 4, the fasteners of which bear on the ceramic sleeve 3 and the radiator 5 and are brazed at 41 and 40 respectively on the ceramic 3 and the radiator 5.

Figure 8 shows a portion of the assembly 2 seen from the side.

FIG. 9 represents an element of assembly 2 or assembly 4 seen from the front. Before brazing, this element is circular and we can clearly see the anchor points 21 and 22.

At the time of brazing, and in operation, the cylinder 1 expands more than the part 3 of the ceramic.

As shown in Figure 10, the anchor points 21 then move away from the circumference on which they are inscribed in the absence of soldering or operation.

As shown in Figure 11, the same phenomenon, for all 4 Figure 1, takes place but in reverse. It is the points 41 which anchored on the ceramic 3 remain fixed, the points 40 anchored on the copper 5 which tend to move away.

We can clearly see in Figure 12, in perspective and cut away the assembly, manifold 1, insulator 3, radiator 5 and parts 2 and 4.

The whole is surrounded by fins 6.

Of course, the invention can be applied to all electronic power tubes where the collector is not grounded.

Claims (5)

1. An insulated collector for electronic power tubes, consisting of two coaxial metal pieces, one of which is the real collector which is under voltage during operation, whereas the other consists of an outer sleeve (5) which surrounds the latter, and of a third, insulating piece (3) which is located in the interspace between the two metallic pieces, the collector further comprising resilient link means (2, 4) between each of the metal pieces and the insulating piece, which means are made of parts of resilient elements located in orthogonal section planes and stacked along the axis and along the entire collector height, characterized in that the elements (30, 31) which are shaped such that they can be axially deformed comprise in alternate manner and on both sides punctual projecting parts (21, 22) through which they are locked to the adjacent pieces in such a way that the resilient parts can be bent in a plane which is parallel to the axis.

2. An insulated collector according to claim 1, characterized in that the resilient elements consist of flat bent metal washers (20), the bending of one axial plane being performed on half of the height of the collector in one direction and on the other half in opposite direction.

3. An insulated collector for electronic power tubes made of two coaxial metal pieces, one of which is the real collector (1) which is under voltage during operation, whereas the other consists of an outer sleeve (5) which surrounds the latter, and of a third, insulating piece (3) which is located in the interspace between the two metal pieces, the collector further comprising resilient link means (2, 4) between each of the metal pieces and the insulating piece, which means are made of elements (10, 11) presenting resilient parts (13, 17), these parts being located in orthogonal section planes and stacked along the axis and along the entire collector height, characterized in that the elements (10, 11) which are shaped such that they can be axially deformed and the resilient parts (13, 17) comprise respectively first projecting parts (12, 15, 16) and second punctual projecting parts on both sides of the first parts or inserted there-between, by which parts they are locked to the pieces between which they are placed in such a way that the bending of the resilient parts (13, 17) in a plane which is parallel to the axis is also possible.

4. An insulated collector according to claim 3, characterized in that the parts of the resilient elements which are stacked parallelly to the axis of the collector belong to two types of elements, each comprising, along generating lines of cylinders which are coaxial to the collector, side beams (15, 16), a backbone (12) and resilience slots, these slots separating frustums of side beams for the first type and frustums of backbone for the other type.

5. An insulated collector according to claim 4, characterized in that the two types of elements (10, 11) are formed of rectilinear and parallel bars, the bars (13) of one type being mutually connected on one side by a central backbone (12) at right angles, and being grooved in their center on the other side along the greatest part of its length, whereas the bars (17) of the other type are mutually connected at their end by two side beams (15, 16) at right angles on one side and bear central projections on the other side, these types being disposed alternately around the axis and the side beams and backbones being directed parallelly to the axis and alternately turned to the inside and to the outside.

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