US2056641A

US2056641A - Electric discharge tube

Info

Publication number: US2056641A
Application number: US333666A
Authority: US
Inventors: Zecher Gustav
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1928-03-24
Filing date: 1929-01-19
Publication date: 1936-10-06
Anticipated expiration: 1953-10-06
Also published as: FR669314A

Description

Oct 1936. G. ZECHER 2,056,641

ELECTRIC DISCHARGE TUBE Filed Jan. 19, 1929 Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE 2,056,641 ELECTRIC msomm'cu TUBE Application January 19, 1929, Serial No. 333,666 In the Netherlands March 24, 1928 '1 Claims.

This invention relates to an electric discharge tube and particularly to an incandescent cathode electric discharge tube adapted to emit rays, preferably ultra-violet rays.

It is known to assist the ignition of such discharge tubes by providing one or more auxiliary electrodes.

During the operation of such discharge tubes the disadvantage may accrue that a part of the tube wall which is intended for the transmission of the rays, is covered by disintegrated cathode material. Thus the transparency of the said part of the tube wall to rays is decreased and the efliciency of the discharge tube is materially reduced.

According to the invention, in an incandescent cathode electric discharge tube for the emission of rays, preferably of ultra-violet rays, the incandescent cathode and the part of the tube wall which is intended for the transmission of rays have arranged between them one or more screens which serve at the same time as auxiliary electrodes.

Such a discharge tube may be so constructed as to have extending within the discharge space a tube which may contain the substance to be irradiated one or more screens being arranged between the end of the said tube and the incandescent cathode.

Preferably the incandescent cathode is surrounded by a cylindrical screen.

The invention will be more clearly understood by reference to the accompanying drawing, showing some electric discharge tubes adapted to irradiate substances with ultra-violet rays.

In Figure 1 the part of the tube wall which is intended for the transmission of ultra-violet rays and which may be, for example, of quartz, is designated by I. This quartz part i has sealed to it glass parts 2 and 3. The stem 3 has mounted on it an incandescent cathode 4 and a screen 5 which are connected to the leading-out wires 6 and l or 8 respectively. The screen 5 prevents the quartz wall I from being struck by particles disintegrated from the cathode and serve at the same time as an auxiliary electrode. The anodes 9 and ID are arranged in the part 3 of the tube.

Referring to Figure 2, the wall ll of the discharge tube which may be of glass for example, has sealed to it a tube l2 which extends within the discharge tube H and which is made of a material that is transparent to ultra-violet rays, for example, of quartz. The tube l2 has sealed to it a side tube I3 and also a tube I I which is The discharge tube II has two lateral arms 15 which have arranged in them the anodes l8 that are taken through the tube at i'l.

- The stem i8 01 the discharge tube has mounted on it an incandescent cathode l9 to which leading-out wires 20 and 2i are connected and has moreover fixed to it a cylindrical screen 22 which protects the end of the quartz tube i2 from material particles disintegrated from the incandescent cathode l9. The screen 22 is connected to the leading-out wire 23 and is thus enabled to serve at the same time as an auxiliary electrode.

The substance to be irradiated is admitted through the tube It, ascends through the tube l2 and is discharged through the side tube l3. During this circulation the substance may be irradiated with ultra-violet light generated in the discharge space of the tube I.

The discharge tubes are filled with a suitable gaseous filling, for example, with a mixture of argonand mercury vapour which during the discharge gives ofl light rich in ultra-violet rays.

What I claim is:

. 1. An electric discharge device for the emission of ultra-violet light rays, comprising an envelope providing a discharge space and containing a cathode adapted to be heated to incandescence, an anode, an auxiliary, starting electrode, and a gaseous filling, said auxiliary electrode forming a screen located in the discharge path between said anode and cathode and being arranged between said cathode and the part of the envelope wall through which the ultra-violet light rays are emitted.

2. An electric discharge device for the emission of light rays, comprising an envelope providing an enclosed discharge space, and containing a cathode adapted to be heated to incandescence, an anode, an auxiliary electrode and a gaseous filling, said envelope comprising a re-entrant tube adapted to contain a substance to be irradiated, said auxiliary electrode forming a screen and being arranged between said cathode and-the end of said tube extending within the envelope.

3. A gas filled electricdischarge device for the emission of ultra-violet light rays wherein the cathode material is normally vaporized by positive ion impact thereon and deposited as an opaque coating on the envelope wall, comprising an envelope providing a discharge space and containing a cathode adapted to be heated to incandescence, an anode, an auxiliary, starting electrode, and a gaseous filling, the said auxiliary electrode forming a screen for intercepting particles from said cathode and being located in the discharge path between said anode and cathode and being between said cathode and the part of the envelope wall through which the ultra-violet rays are emitted.

4. An electric discharge device for the emission of light rays comprising an envelope, a

filamentary cathode adapted to be heated to in-' candescence, an anode, and an auxiliary electrode and a gaseous filling, said envelope having a reentrant part adapted to contain a substance to be irradiated extending therein, said auxiliary electrode forming a screen and being arranged I between the said filamentary cathode and the end of said re-entrant part extending within the envelope.

5. As a unitary structure, an envelope having a re-entrant tubular part for the passage of matexial to be irradiated, and containing a cathode tubular part of smaller diameter or said envelope thereby deilning a reverse path for material to be irradiated, the said tubular part or smaller diameter being formed of material permeable to ultra violet rays, said envelope providing a discharge space and containing a cathode adapted to be heated to incandescence, an anode, an auxiliary electrode and a gaseous filling, the said anode being mounted in a tubular portion of!- set with respect to and communicating with that end 01' the discharge space remote from the said cathode, the said auxiliary electrode forming a screen and being arranged between said cathode and the part of the wall of the tubular part of and the re-entrant part of said envelope.

GUSTAV ZECHER.