US2933633A - Electric discharge device - Google Patents

Description

April 19, 1960 H. c. SPICER EI'AL 2,933,633

ELECTRIC DISCHARGE DEVICE Filed Feb. 16, 1955 2 Sheets-Sheet 1 FIG! FIG.2 v

lNVENTORS RICHARD F. HAMMOND,

HUGH c. SPICER,

April 19, 1960 H. c. SPICER E 2,933,633

\ ELECTRIC DISCHARGE osvxcs Filed Feb. 16, 1955 2 Sheets-Sheet 2 FIG.3

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lNVENTORS RICHARD F. HAMMOND,

HUGH c. SPICER,

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'I'HEIR TOR Y.

United States, Patent Ofiice ELECTRIC DISCHARGE DEVICE Hugh C. Spicer and Richard F. Hammond, Tell City,

Ind., assignors to General Electric Company, a corporation of New York Application February 16, 1955, Serial No. 488,462

3 Claims. (Cl. 313-313) Our invention relates to electric discharge devices and pertains more particularly to a new and improved high voltage electric discharge device.

During the operation of some high voltage electric discharge devices including glass bulbs, such as high voltage regulator and rectifier tubes used in television receivers, the interior surfaces of the bulbs are bombarded with electrons and are alternately charged and discharged. This sometimes results in the generation of a signal with harmonics extending into the television spectrum and causing radio frequency noise'generally known in the art as diodehausen. The diodehausen manifests itself in some television receivers as undesirable black vertical lines at some particular portions of the raster. Additionally, the charging of the bulbs results in glass electrolysis which is also undesirable.

The primary object of our invention is to provide a new and improved high voltage electric discharge device including means for minimizing the effects of bulb chargmg.

Another object of our invention is to provide a new and improved high voltage tube adapted for use in television receivers and including means for minimizing radio frequency noise in the receivers.

Another object of our invention is to provide a new and improved high voltage electric discharge device including a vitreous envelope and means for minimizing electrolysis in the walls thereof.

Further objects and advantages of our invention will become apparent as the following description proceeds and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In carrying out the objects of our invention we provide an electric discharge device including a vitreous envelope provided with a metallic deposition on the interior surface thereof. The metallic deposition is preferably lead andmay be applied by providing in the envelope a material which will vaporize and flash onto a portion of the walls of the envelope with lead when heated to a predetermined degree. Vaporization of the material and flashing of the lead may be effected by depositing the material on an electrode in the device and electrically heating the electrode. The methods of producing the electric discharge device and electrodes are described and claimed in our co-pending divisional application Serial Number 817,429 filed May 12, 1959, and assigned to the same assignee as the present invention.

For a better understanding of our invention reference may be had to the accompanying drawing in which:

Fig. 1 is an elevational view of an electric discharge device incorporating our invention and partially broken away to illustrate the manner in which the metallic deposition is provided on the interior surface of the bulb;

Pig. 2 is a somewhat schematic illustration of one manner in which our invention may be practiced;

Fig. 3 is a fiow chart illustrating one manner of preparing electrodes for use in our invention; and

for preparing the electrodes.

Referring to Fig. 1, there is shown an electric dischargedevice in the form of a high voltage rectifier tube generally designated 1. The tube 1 includes a glass bulb or envelope 2 in which is housed a cylindrical anode 3 mounted in a suspended manner in the envelope by means of a top cap 4 which extends through and is suitably sealed in the top portion of the envelope.

The anode and top cap are often collectively referred to as an anode assembly. Mounted in the envelope by means of a pair of vertical support rods 5 and disposed in the anode 3 is a filament or cathode 6. Suitably sup ported beneath the anode 3 and in spaced relation thereto is a shield 7. Suitably secured to the lower end of the envelope 2 is a base 8 carrying a plurality of base pins and a bayonet plug 10 adapted for facilitating insertion of the pins in a tube socket. Leads 11 are electrically connected to the various pins 9 and extend in a sealed manner through the lower end of the envelope for making electrical connections to and supporting the filament support rods 5 and the shield 7 in the envelope. Also, as indicated above, the described methods of producing electric discharge devices and electrodes are claimed in our copending divisional application Serial Number 817,429.

During normal operation of a high voltage rectifier tube such as that described to this point and not incorporating our invention, the interior surface of the bulb 2 is bombarded by electrons and tends alternately to charge and discharge. This charging and discharging is frequent and abrupt and often results in radiation of energy and generation of a signal with harmonics extending into the television spectrum. As a'result, if the tube is used in a television receiver, it causes radio frequency noise generally referred to in the art as diodehausen. Diodehausen sometimes manifests itself in a television receiver as a black vertical line appearing at some particular portion of the raster, such as the left hand edge. Additionally, the referred-to electron bombardment of the glass causes undesirable glass electrolysis.

The bulb charging described above is ordinarily most.

prevalent or concentrative in the annular area extending between the bottom of the anode 3 and the top of the shield 7 and defined by the spaced dash lines 12 in Fig. 2. In order to minimize the bulb charging and thereby avoid diodehausen in television receivers utilizing tubes such as 1 and to minimize glass electrolysis, we vaporize a material in the tube in the vicinity of the area defined by the lines 12, whereby a thin lead deposition indicated by stippling designated 15 in Fig. 1 is provided on the interior surface of the bulb. The deposition 15 extends over and beyond the area ordinarily bombarded by electrons during tube operation but is not so extensive as to effect a conductive path between the top cap 4 and the leads 11.

The lead deposition 15 is effective for distributing the charge or conducting the electrons bombarding the walls of the bulb in 'this area in such a manner that large charges are prevented from building up or accumulating in any particular spots or areas. This reduces the abovereferred'to energy radiation or signal generation to the extent that when a tube such as that described is employed in a television receiver diodehausen is not en-" countered. Additionally, due to the reduction of the concentrated charging by the metallic deposition 15 glass electrolysis is minimized. As a result, in some tube struc-' tures Where lead glass was formerly used because .of its relatively high resistance to current flow, with our inven-J tion a relatively less expensive glass such as lime glass may be employed. In some other tube structures where it is desired to use much higher voltages and where elec trolysis effects would be encountered even where lead Patented Apr. '19, 1960;

, anode through the oven. 7

V 3 l glass is employed'our invention may be advantageously utilized in conjunction with the lead glass.

The lead deposition 15 is preferably applied by substantially uniformlydistributing in the rim or rolled lip 16 of the anode 3a deposit 17 of material which when sufilciently heated will volatilize and flash lead on the interior of the bulb. 7

As seen in Fig. 2, the heating may be done inductively by an induction coil 13. Additionally, the flashing of the material 17 may be carried out before the tube 1 is tipped-oil and while it is being processed on the usual tube processing equipment.

Specifically, the lead may be flashed on the bulb while the tube 1 is held by its exhaust tubulation 19 in an exhaust head 2% of the mentioned usual processing e uipment and while the anode 3 is being inductively heated by means of the coil 13 for elfecting out-gassing thereof.

The flashing of the lead onto the bulb occurs at approximately 390 to 900 C. Thus, it will be seen that by uniformly distributing the material 17 in the anode rim l6 and by taking advantage of the step of heating the anode for outgassing we accomplish the provision of a lead deposition or coating 15 on the interior surface of the bulb which is substantially uniformly distributed around the tube and covers and extends beyond the area in which bulb charging is most prevalent in an ordinary rectifier tube.

The material 17 which is adapted for vaporizing and flashing the load deposition 15 on the wall of the bulb is preferably lead or any suitable compound of lead, such as basic lead carbonate, which will break down to uncombined lead when heated sufficiently under. exhaust conditions or when heated sufficiently in a vacuum.

In Fig. 3 is illustrated a method of providing a substantially uniform deposit of basic-lead carbonate in the rim 16 of an anode 3. In this method the anode is dipped with the rimmed edge downward into a receptacleZl' containing'a suspension of basic lead carbonate designated 22.

. Following clipping of the anode 3 in the suspension 22 in the manner illustrated in Fig. 3, the anode 3 is set to drain on a drainboard 23 or the like. Thus, the rim 16 is filled with a quantity of the suspension 22.. Following draining, the anode is placed in a suitable drying oven 2 In the oven the anode is heated for evaporating the liquid constituent of thesuspension in the anode rim. Thus, a substantially uniformly distributed deposit or residue of basic lead carbonate 17 is left in the anode rim. It will be seen that a plurality of anodes may be held in a rack or the like and dipped, drained and dried together to increase production.

' After preparation of an anode in the just-described 'manner it may be mounted or suspended in the bulb by" means. of a. suitable glass-to-metal seal between the bulb and the top cap 4-, and the bulb may be sealed to the tube stern including the tubulation 19 thereby to arrive at the structure shown in Fig. 2. Thereafter, the tube may be processed in the usual manner and, as described In Fig. 4 is illustrated "an automatic method of pre paring the anodes. In this method the anodes are placed on conveying means generally designated 25- adapted a supply of the suspension 22 and then through a suitable .oven2-7. The oven 27 is similar in construction and purpose to that referred to above and designated 24 in Fig.

. 3, but is relatively and preferably longer in order to enable complete evaporation of the liquid constituent of the suspension in the anode rim during transit of the By means of a tube 28 including a control valve 39 and automatic means generally designated 31 adapted conveying means 25 is thereafter effective for directly carrying the anode into and through the elongated oven 27 wherein the liquid portion of the suspension is evaporated leaving in the rim a deposit 17 of basic lead carbonate to be flashed. Thereafter the anode is automatically removed from the conveying means and at this stage it is prepared for mounting in the bulb 2 and flashj ing of the basic lead carbonate for providing the lead deposition 15 in themanner described above with regard to Fig. 2. Y

While we have shown conveying means including what is illustrated as a conveying belt, the conveying means may take any form. For instance, a chain drive or the like including clamping means or magnetic holding means for holding the anode assemblies by the top caps 4 thereof and thus carrying them to and positioning them at a reservoir such as 26 and through an elongated oven such as 27 may be employed. V

The lead suspension utilized in both of the above-described methods'of preparing the anodes 3 may be a leadmethanol corrosion product. In an'operative arrangement we have found that the product may be prepared by taking a sheet of lead of approximately twelve square feet, rolling it to form a cylinder and immersing it in ap proximately twenty-eight gallons of commercially available methanol for approximately twenty-four hours. A suspension obtained in this manner is particularly satisfactory in that it requires no agitation to prevent settling and assures substantial uniformity in the amounts of lead carbonate received in the rims of successively processed anodes. It will, of course, be understood that the'foregoing is exemplary only and is not intended to be limiting in any manner.

' positioning each anode first at a reservoir 26 containing also generally commercially available.

The suspension 22 may also be prepared from powdered basic lead carbonate popularly known as white lead and generally commercially obtainable. First, a stock or paste may be prepared by mixing approximately 450 grams of white lead and approximately 300 cubic centimeters of generally commercially available amyl acetate.

This mixture is then milled, asby ball milling, for ap-' proximately ninety-two hours to minimize settling during use. The stock or paste obtained in'the first described manner is used in proportions of approximately one and one-half cubic centimeters to a gallon of acetone which is A suspension obtained in the just-described manner is particularly adaptable for use with the automatic or machine filling method shown in Fig. 4 because of its drying and low odor qualities. Additionally, for most satsifactory results and, specifically, in order to avoid settling and thereby insure substantially uniform amounts of lead carbonate in the rims of successively filled anodes, it is advisable to agitate the suspension obtained by using the powdered basic lead carbonate;

It will be understood that the suspension 22 may be one of uncombined or metallic lead; Additionally, while the use of the suspension for depositing the basic lead carbonate in the anodes 3 has been found expedientfrom a manufacturing standpoint, if desired the lead or lead compound may be directly placed or deposited in the rim.

It is to be understood further that while we have shown and. described the material to be flashed as deposited in the anode rim, this, material could alternatively be held in any desired manner adjacent the region or area to be circuit completed through appropriate ones of the pins 11, thereby to raise the temperature of the material to the flashing point.

While we have shown and described specific forms of our invention we do not desire our invention to be limited to the particular forms shown and described, and we intend by the appended claims to cover all modifications within the spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An electric discharge device comprising; a plurality of electrodes, a cylindrical vitreous envelope containing said electrodes and having said electrodes cooperating in the central region thereof, conductive elements extending through and sealed in both ends of said envelope and connected tosaid electrodes, said envelope having an internal annular surface area subject to concentrative electrical charging during normal operation of said device, said area being confined to the central region of said envelope immediately adjacent said electrodes and substantially longitudinally spaced inwardly from both ends of said envelope and said seals, and a continuous annular elemental lead flash on only said internal surface area and efiective for distributing electrical charges thereon, said flash being substantially longitudinally spaced and electrically insulated from all conductive elements in the walls of said envelope.

2. A high voltage electric discharge device comprising; a plurality of electrodes including a tubular anode, an elongated glass envelope containing said electrodes, conductive elements extending through the opposite end walls of said envelope and connected to said electrodes, said conductive elements including an element mounting said anode from one end of said envelope and supporting said anode in said envelope in spaced relation to the side walls thereof, said envelope having an intermediate annular internal surface area immediately adjacent the inner end of said anode subject to concentrative electrical charging during normal operation of said device, whereby undesired energy radiation and glass electrolysis are effected, and an annularly continuous elemental lead flash on only said annular internal surface area of said envelope being effective for distributing electrical charges thereon, thereby to minimize said undesired energy radiation and glass electrolysis, said flash terminating at points substantially longitudinally spaced inwardly from said opposite end walls of said envelope and said conductive elements sealed in said end walls, said flash being electrically insulated from all electrodes in said envelope and from all conductive elements in the walls of said envelope, and said lead flash relying on the thinness thereof to afford highresistivity conduction for said electrical charges.

3. A high voltage rectifier device comprising; an elongated cylindrical glass envelope, said envelope containing a filamentary cathode and a cylindrical anode surrounding said cathode, said anode being mounted in said envelope in spaced relation to the walls thercofby a conductive member extending through one end of said en velope, said cathode being mounted in said envelope by leads extending through the opposite ends of said envelope, a shield member in said envelope between said anode and the opposite end of said envelope and surrounding said leads, said envelope having an annular internal surface area which is substantially coextensive with the space intermediate the inner-most end of said anode and said shield member and subjected to concentrated electric charging during normal operation of said device, and an annularly continuous lead deposition on and confined to only said annular intermediate surface area of said envelope, said deposition terminating at points substantially longitudinally spaced inwardly from both ends of said envelope and said conductive members and leads extending therethrough, and said deposition comprising an extremely thin flashing diminishing in thickness toward the marginal regions thereof and being electrically insulated from all elements in said envelope and from all conductive elements in the walls of said envelope.

References Cited in the file of this patent UNITED STATES PATENTS 1,128,817 Pickard Feb. 16, 1915 1,273,628 Langmuir July 23, 1918 1,583,414 Gill et al May 4, 1926 1,626,693 Rentschler May 3, 1927 1,832,607 Zworykin Nov. 17, 1931 1,917,044 Loewe July 4, 1933 1,958,953 Parker May 15, 1934 2,129,314 Boumeester Sept. 6, 1938 2,275,864 Record Mar. 10, 1942 2,325,110 Colborne July 27, 1943 2,487,437 Goldstein et a1. Nov. 8, 1949 2,588,920 Green Mar. 11, 1952 2,597,562 Blodgett May 20, 1952 2,617,741 Lytle NOV. 11, 1952

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