US1886795A

US1886795A - Electric discharge tube

Info

Publication number: US1886795A
Application number: US755274A
Authority: US
Inventors: Dijksterhuis Popko Reinder
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1924-01-15
Filing date: 1924-12-11
Publication date: 1932-11-08
Anticipated expiration: 1949-11-08

Description

Nov. 8, 1932.

P. R. DIJKSTERHUIS ELECTRIC DI SCHARGE TUBE Popko Remder Dkeerhus ttorneg Patented Nov. 8,1932

UNI'IEDV STATES PATENT OFFICE Torno BEINDEH DIJxsTEnHUIs, or EINDHOVEN, NETHERLANDS, AssIGNoa To N. v. ,PHILIrs eLoEILmrENEABaIEHEN, or EINDHOVEN, NETHERLANDS ELECTRIC DIscHAneE TUBE Application illed December 11, 1924, Serial No. 755,274, and in the Netherlands January 15, 1924. Renewed November 10, 1980.

The resent invention relates to the attachment o electrodes in electric discharge tubes, more particularly to the attachment of the incandescent cathode, the anode and one or more grid shaped electrodes in discharge tubes.

Usually, the cathode is made in the shape of an elongated V, the two sides of the V being connected to the leading-in wires, and the apex of the V being connected to a'metallic hook which is secured to and insulated from another electrode.

A spring made of tungsten or similar material, is frequently used to keep the filament rigidly stretcheds It has however been found that such a spring loses its tension in course of time and therefore in the construction according to the invention a spring is preferably omitted.

It has, moreover, been found that the insulating `material to which the hook is secured, ecomes more or less conductive owing to the high temperatures to which it is y exposed, and it also occurs frequently that the material which is disintegrated or which volatilizes from the filament, precipitates on the insulating material in such a degree'thatV conduction may occur along the surface of the said material.

An object of the invention is to protect the insulating material from excessive heat, because at high temperatures the insulating material may become conductive. Another' ob- ]ect of the invention is to shield the insulating material from the hot filament in order to prevent any volatilized matter from the filament from being precipitated on the insulating material. y p c According to the invention a screen is arranged for this purpose between the cathode and the material by means of which the supporting or suspending device of the cathode is attached so as to be insulated from the` members which carry the current.

Between the points of attachment the incandescent cathode is preferably suspended to or supported by one or more metal hooks which are secured to one or more supporting devices with the aid of insulating material.

or hooks may be secured to one or more supporting ieces made of quartz or similar material; t esepieces are supported by metal members which are connected to another electrode and the hook or hooks are led through one or 4more apertures provided in a plate which likewise is secured to the other electrode.

According to the invention, in a discharge tube like the one abovementioned, comprising an anode and a grid and in which the electrodes are arranged concentrically, the grid supports or their extensions may be provlded with transverse rods carrying little tubes made of quartz or similar material whilst .the hook or hooks for supportin the cathode is or are attached to the said tu es by means of a clamp or a resilient connection. The resilient connection serving for the attachment of ahook is preferablyan S-shaped plate.

In discharge tubes according to the invention it is of great importance that means are provided for keeping the other electrodes so rigid in their places that a displacement of the electrodes relative to each other during the operation of the discharge tube cannot occur. According to the invention the anode or another electrode which does not act as a cathode, is attached for this purpose to a re-entrant glass tube, by means of a number of supports, the ends of which are secured to a closed or open ring which is arranged around the glass tube at some distance from the end; the supports are `provided in this case with lateral arms the ends of which are sealed into the end of the glass tube.

If two grid-shaped electrodes have to be arranged in the discharge tube, they may be attached according to the invention on one side to a re-entrant glass tube, whereas their other ends are kept spaced at the required distance from each other by means of an insulating connection.

According to the invention the supports of 'each of the grid-shaped electrodes may fur- 'o 'According to the invention the metal hook the like.- According to the invention the ends 100 tween the filament of each pair of supports may be located in one line and may be connected to each other by means of a straight piece of a tube made of quartz or similar materiah The accompanying drawing illustrates by way of example a construction of a discharge tube comprising` an incandescent cathode according to the invention. In the said drawing: Figure 1 is an elevation of a discharge tube comprising an incandescent cathode, and anode and two grid-shaped electrodes.

Figure 2 is a detail View showing the attachment of the hook lof the filament to the tubes made of quartz.

Figure 3 is a detail view showing the attachment of the anode to a re-entrant glass tube.

Figure 4 is a plan of the plate located bcand the securing device ofthe hook which supports the filament.

The discharge tube shown in the drawing, is formed by a glass bulb 1 to which a twice bent glass tube 2 is hermetically sealed.

Leading-in wires 4 and 5 for a cathode 6 are hermetically sealed into the clamped portion of the innermost glass tube 3. The cathode 6 has the shape of an elongated V and is suspended at its apex to a metal hook 7 which is attached to an S-shaped plate 8 (see Figure 2) which clamps itself elastically on to tubes 9 and 10 which are made of quartz and through which pass little rods 11 and 12.

The hook 7 passes through an aperture provided in a metal plate 16 which is carried by a grid-shaped electrode 15. Thls plate protects the quartz tubes 9 and 10 from being heated too high by theilament whilst at the same time it intercepts the material volatilized from the ilament.

The rods 11"-and 12 are secured to lengthening pieces or extension rods of

supports

13 and 14 of the grid-shaped electrode 15 which consists of a metal Wire helically wound on four supports, only two being shown in the drawing. The other ends of these supports are connected to a resilient clamp 19 which may be of any known construction and which is slid on the end of the glass tube 2. A leading-in wire 17 for the electrode 15 is secured to the metal c1amp119 and is hermetically sealed into a little tube 181.

A second grid-shaped electrode 20 is concentrieally arranged around the cylindrical electrode 15. The electrode 2O also consists of a metal ports, only ing shown. Encircling said supports and secured thereto are

metal rings

28 and 29. These supports are connected at one end to a flexible metal plate 23 which is clamped on to the tube 2 by means of a spring plate 24. A wire 25, the end of which is connected Vto a clamp 24 and which is hermet-ically sealed into a glass tube 41, serves for carrywire helically wound on four sup-v two such supports 21 and 22 beh ing the current to the electrode 20. The

other ends of the electrode supports 21 and y 22 .are provided with extension rods which of, a hook so that the lengthening-pieces 0r are bent in the shape ends are brought into alignment with the extension rods of the

supports

13 and 14 of the auxiliary electrode similar to that shown and described for

supports

13, 14 and 21, 22.

A cylindrical anode 30 is arranged around the electrode 20 and is carried by four

supports

31, 32, 33 and 34, the lengtheningpieces or extension rods of which are secured to a metal ring 35 which is arranged loosely around the re-entrant glass tube 36. The four supports are further secured to

lateral arms

37, 38, 39 and 40 which are sealed into a clamped portion or press, commonly socallcd, at the end of the tube 36. f Although it is not necessary to lead all these four arms through the glass and it would be satisfactory to lead only one wholly through the glass it is advisable to make use of the construction shown in the drawing because in this case a very rigid attachment of the electrode is obtained.

It must be observed, in addition, that the discharge tube according to the invention is preferably so arranged during its operation that the top of the filament hangs down as is shown in the drawing. If during the operation the incandescent cathode becomes hot and expands, the apex of the cathode in the hook 7 is free to move downwards so that the cathode wire is prevented from being distorted.

lVhat I claim is rl. A -discharge tube having a plurality of electrodes including a cathode and at least one grid with its supports, said grid supports having transverse rods of insulating material, and. hooks to support the cathode, said hooks being attached to the transverse rods by means of a resilient S shaped plate.

2. A discharge tube having a plurality of electrodes including a cathode and at least one grid with its supports, said grid supports aving transverse rods of quartz, and hooks to support the cathode, said hooks being attached to the transverse lrods by means of a resilient S shaped plate.

3.v A discharge tube having a cathode and at least one other electrode, said other electrode being fastened to supports, the ends of the supports being secured to a ring arranged around a reentrant glass tube, said ring being llt) assumes positioned at a distance from the end 0f the tube, and lateral arms extending from said supports, the ends of these arms being sealed into the end of the reentrant tube.

4. In a discharge tube having a cathode, plate and double grid, a plurality of rod supports secured at one end upon which one grid is supported, and a plurality of rod supports 'secured at one end upon which the other grid is supported, the free ends of the two sets` of grid supports being connected by means of insulators.

5. In a discharge tube having a cathode, plate and double grid, a plurality of'rod supports secured at one end upon which one grid is supported, a plurality of rod supports se- ,cured at one endvupon which the other grid is supported, the free end of each supporting rod of one set of supports being bent so that the end is in alignment with one of the supports of the other grid, and an insulator securing the two ends together.

6. In a discharge tube having a cathode,

`plate and double grid, a plurality of rod supports secured at one end upon which one grid is supported, a plurality of rod sup orts secured at one end upon which the ot er grid is supported, the free end of each supporting rod of one set of supports being bent so that the end is in alignment with one of the supports of the other grid, and quartz tubes securmg the two ends together.

A discharge tube comprising an anode, cathode, and grid, a tensioning member for the cathode, an S-shaped plate, the tensioning v