SU405140A1 - NONALUNDED HEATER - Google Patents

Description

one

The invention relates to the field of design of vacuum devices, in particular, cylindrical cathode heaters of high-power electronic tubes.

For modulators and generator lamps of average power with heated cylindrical cathodes, so-called non-alundant heaters have become widespread. Such a heater contains a cylindrical insulator and a filament body located on its surface; The insulator is made in the form of a metal frame with holders of an alundum kerama. In the form of combs with grooves attached to the frame along the cylindrical surface forming it, and the grooves of the body are fixed in the slots of the combs. The need for such heaters, until recently, was limited to the application in lamps with a heating current of up to 10 and (heating power up to 250 W).

In connection with the need to use non-huddled heaters for ivromic lamps (the power of heating is from several hundred watts to values exceeding 1000 from), it is necessary to tantalize the number of parallel-connected turns of wire and its diameter. However, when performing the bends required for parallelly bringing the lamp shears to the electrode, mechanical stresses increase in thick wires. If, for some reduction of mechanical stresses in the wires, the filament body is made in the form of a multi-way spiral, then due to the increase in the winding pitch, which increases with the number of its approaches, the teeth of relatively thin alundum combs are subjected to large stresses, and the hardening of these combs requires an increase their thickness, which is not advantageous because of the large specific heat capacity of keraglik, and, consequently, an increase in the heating time of the cathode. In addition, the contact of the filament body with the leg electrode when welding to the last beam {3 of thick refractory wires is not reliable.

All of this makes it difficult to manufacture foot-mounted heaters of known design for high-power lamps; this makes heaters not reliable enough, as during operation wire stranding, breaking of combing elements with emergency closing turns, as well as breaking of contacts in the place of welding a wire beam to an electrode can occur. .

The purpose of the invention is to improve the reliability of a non-tuned preheater with a high heating current, i.e., in high-power electronic tubes.

The goal is achieved by the fact that the proposed non-alundane heater contains a bus terminal located between the nilindrical surfaces of the metal frame and the wire turns of the body of the heat in parallel with the core, connected to the metal frame with at least one insulator, on the outside of which is located at least at least one alundum groove comb, similar in groove pitch to combs attached to the metal frame, is made with a smaller height. In this case, the filament body is made of parallel-connected (one-turn spirals with fixed pin on the pin and pin of the pin.

The isolator for connecting the tire output to the metal frame can be made in the form of a short four-channel tube of oval section, through which channels pass wire segments, of which two extreme ones are welded to the metal frame, and the other two to the tire output.

The isolator for connecting the bus terminal to the metal frame can also be made in the form of a figured alundum washer with two holes and two grooves in a plane perpendicular to the axes of the holes; With the help of these grooves, the washer is fastened in the frame slot, and a loop from a wire section passes through the holes, the ends of which are welded to the bus terminal.

The bus terminal can be made in the form of a metal strip, the material and the cross section of which are chosen with regard to the current load of the heater with width and thickness, providing gaps between the metal tape and the cylindrical surfaces of the metal frame and the filament body not less

1 mm.

FIG. 1 is given an axopometric projection of the proposed non-aluminized heater; pas figs. 2 and 3 - two variants of the heater heater design, top view; in fig. 4 and 5 show the connection of the bus terminal with a metal frame, two options; in fig. 6 is a section along LL in FIG. four; in fig. 7 - section bb pa of fig. five; in fig. 8 is a section, but BB, in FIG. five.

The proposed heater (Fig. 1) contains a metal frame / made of niobium tin 0.2 mm thick; five holders 2 of alundum ceramics in the form of combs welded to the metal frame with niobium bushes 3 passing through slots in the combs; the filament body in the form of four parallel-connected single-wire wire spirals 4 made from a tungsten alloy with a rhenium of 0.4 mm in diameter, each of which has two turns and is welded to the metal frame with one end; bus terminal 5, 7 mm wide, 0.2 mm thick, made of pyobium tin, to which the other ends of each coil of the heat body are welded; insulators 6, with the help of which pin 10 is attached to frame 1; an alundum comb 7 pa to the outer side of the pin 5 is smaller than the combs 2

2.5 mm, attached to the bus terminal 5 by means of 8 from niobium passing through the free slots of the comb.

Pa figs. 2 shows the location of the tire

pin 5 with respect to the metal frame 1 and the filament body 4 and the connection of this tire lead to the metal frame / using insulator 6, where the segments 9 and / O wire are used to attach the insulator 6 to the tire lead and to the metal frame; in fig. 3 shows the connection using an insulator // of another design; loop 12 from the wire section, used to fix the bus terminal 5 to the isolator //.

In the first variant of connecting the bus terminal 5 with the metal frame Y (Fig. 4), through the two extreme channels of the insulator 6, which is a short four-channel tube of oval section, cut the wires 9, the ends of which are welded to the metal frame. The ends of the wire segments 10 run along two middle channels of the insulator 6 and are welded to the bus terminal 5 (Fig. 6).

In the second variant of connecting the bus terminal 5 with an insulator // through its two central holes, a loop 12 passes from the wire section. For such a connection, there are two holes in the bus terminal 5, the positon of which is matched with the holes of insulator 11. Insulator 11 is fixed in the metal frame 1 by means of grooves (Fig. 7); The insulator 11 is located in the slot of the metal frame /, the edges of which, connected by a cr.1arka, do not allow it to fall out of the framework (Fig. 8).

The metal frame and the filament body have a cylindrical shape of surfaces, the curvature of which and the distance between them limit the width and thickness of the tire output 5. In order to avoid emergency short circuits of the IININ output with the metal frame and the filament body, the gaps between the tire output 5 and the metal frame 7,

as well as between the body and the body must be at least 1 mm. At the same time, the minimum dimensions of the cross section of tire output 5 and its material must correspond to the current load of the heater. The proposed heater has a filament body, which is connected to the incandescent circuit via bus terminal 5 and metal frame I, which are connected for this purpose with the incandescent and electrodes of the electron tube. The metal frame of the paralyzed preheater is attached to the cathode.

If it is necessary to completely isolate the filament body from the metal frame, a second tire output can be inserted into the structure with welded to it (instead of the metal frame) ends of the body filaments, similar to that described.

The proposed non-alundane heaters are tested with a satisfactory result in two modulator lamps, and the heat intensity is 420 and

1000 watts respectively.

The subject matter of the invention

Claims (3)

1. A non-alundumized heater for cylindrical cathodes containing a body. A filament located on a surface-insulator made in the form of a metal cylindrical frame with holders of alundum ceramics in the form of combs with grooves attached to the frame along its cylindrical surface, and in the slots the comb is secured by the turns of the incandescent body, characterized in that, in order to increase the reliability of the preheater at a high incandescent current, it contains a terminal terminal located between the cylindrical surfaces mi metal frame and wire turns of the filament body, embodied as a parallel-connected single-loop coils with attached schinnom output ends in a parallel manner and connected to the metal frame via at least one insulator, on the outer side of which there is at least one additional alundum comb with grooves, similar to the slot of the grooves to the combs attached to the metal frame, but having a smaller height. 2. The heater according to claim 1, characterized in that the insulator for connecting the tire output to the metal frame is made in the form of a short four-channel tube of oval section, through the channels of which wire segments are passed, of which two extreme ones are connected to a metal frame, and the other two are connected to a bus terminal. 3. The heater according to claim 1, characterized in that the insulator for connecting the female output to the metal frame is made in the form of an alundum washer with two openings and two grooves in a plane perpendicular to to the holes, with the help of grooves the washer is fixed in the slot of the metal skeleton, and the loop through the hole in it passes a loop from a piece of wire, the ends of which are connected to the busbar output. FIG. one . h Fig.Z xf- / five YU / tfusl 12