Патент USA US2118887код для вставки
May 31, 1938. T, JURRlAANSE ’ MERCURY CATHODE TUBE Filed Feb. l5, 1937 di . 2,118,887 Parenteel May 31, 1938 2,118,887 > UNITED STATÉS EBATÈN’Í GFFICE 2,118,887 MERCURY CATHODE TUBE 'I‘om .lurriaansa Eindhoven, Netherlands, as signor to N. V. Philips’ Gloeilampenfabrieken, Eindhoven, Netherlands Application February 15, 1937, Serial No. 125,943 In Germany February 17, 1936 5 Claims. My invention relates to mercury-cathode tubes, such as mercury arc rectifiers and relays, and more particularly to the anchoring of the cathode spot of such tubes. To stabilize the operation of such tubes, an choring members are used to prevent the cathode spot from wandering over the surface of mercury and to prevent splashing of the mercury. If the portion of the envelope in the vicinity of the cathode is of metal, or of glass coated with a conductive deposit such as mercury, such mem bers prevent the cathode spot from passing over the surface of the mercury and reaching the conductive wall portion. This greatly reduces the possibility of damage to the envelope, and especially to the metal-glass seal of envelopes having a metal portion and a glass portion fused together. As the cathode spot .generally settles at the line of separation between the anchoring mem ber and the mercury, i. e. at the cathode line, the surface at this point must be of perfectly pure metal free from oxides to ensure proper an choring action. This condition can be satisfied in a simple manner by making the anchoring member of a metal capable o_f amalgamating with mercury, as this amalgamation removes the sur (Cl. Z50-27.5) amalgamates better than does iron or molyb denum. The term “dissolving speed in mercury” as used herein and in the claims, is to be understood to mean the loss in material of, the anchoring mem- " 5 ber due, inter alia, to amalgamation with the mercury and to disintegration by the discharge. per unit of time and per unit of. arc current during the operation of the tube. . Anchoring members of such materials have 10 suñ’iciently long life for all practical purposes, and the settling point of the cathode spot upon the anchoring member is formed with full se curity and without taking additional measures, so that the manufacture of the tube is not compli- 15 cated. Furthermore, the materials used are standard and can be obtained at a comparatively low cost. As the dissolving process and any corrosion phenomena at the settling point of the cathode y20 spot depend to a large extent upon the temper ature, it is essential to have a good dissipation of heat from this point. For this purpose I prefer to locate the anchoring member in the middle of the mercury cathode, and in good heat-trans- `25 -ierring relationship with the envelope. ?, In order that my invention may be clearly face layer and its impurities. However, metals which amalgamate sufficiently with mercury, for understood and readily carried into effect, I shall instance copper, dissolve so rapidly in mercury accompanying drawing, in which: especially at the physically highly-stressed point describe same more fully with reference to the ,3o Figure l is a sectional side-view of a mercury at which the cathode spot settles-that the life of the member is reduced to such extent that the vapor rectifier embodying the invention; tube is soon rendered unserviceable. If, to ensure a satisfactory life, the anchoring member is made of a material which is substan ber according to the invention. The rectifier shown in Figure 1 comprises an 35 envelope consisting of a cup-shaped metal mem ber l, for instance of chrome iron, and a glass member 2 hermetically fused together at I1. tially insoluble in mercury, the anchoring proper ties are either very poor, or can be developed only with great difficulty. Thus, a completely satisfactory solution of this problem in a simple manner was hitherto impossible, and a suiiicient life of such members and of the tubes could be ensured only by using extremely pure and expen sive metals such as platinum, or by resorting to extremely complicated purifying methods during the manufacture of the tube. The object of my invention is to overcome the above diiiiculties and to produce an anchoring member which has a long life and satisfactory anchoring properties. According to the invention, I form the anchor ing member from a metal or a metal-alloy whose “dissolving speed in mercury” during the passage of discharge current is less than about £5, prefer 55 ably about 1/40, of that of copper, and which Fig. 2 is a sectional View of an anchoring mem Disposed in the bottom of member l is a mercury cathode 3, whereas a main anode 8 is supported 40 from the lower' end of a conductor 6 Whose upper end is secured to a metal disc 4 hermetically sealed in glass portion 2 and carrying a terminal. Supported from conductor 6 and surrounding anode 8 is a cylindrical screen II serving to 45 protect the higher internal surfaces of portion I and seal Il from the detrimental effects of the discharge. Supported by screen Il, preferably of sheet molybdenum,'is an insulating tube 20 through 50 the bore of which extends a conductive rod I9 carrying on its lower end an auxiliary anode 9. The anode 9 is adapted to be moved in the direc tion of the double-headed arrow, and for this purpose the upper end of rod I9 carries a plunger 55 2 2,118,887 I8 of magnetic material electrically connected` through a compression spring 22 to a core 2| of a magnetic material. Core 2l is supported `from the lower end of a conductive rod 1 secured to a disc 5 hermetically sealed in glass portion 2. Outside the envelope and surrounding core 2I is coil III which serves to raise anode 9 from the surface of the mercury. Surrounding metal member I is a cooling jacket 10 I 2 having an inlet opening I3 and an outlet open ing I4, and through which a. circulating cooling medium, such as Water, is circulated in the direc tion of the arrows during operation of the recti ñer. Jacket I3 is secured to metal member I by 16 a copper bolt I5 secured, for instance, by Welding the appended claims to be construed as broadly as permissible in view of the prior art. What I claim is: 1. A mercury-cathode tube comprising an en velope having a wall portion of mercury-resistant metal forming part of the bottom thereof, elec trodes within said envelope including a mercury cathode Within the bottom part, and a massive cathode-spot anchoring member partly Within said mercury cathode and carried by said metal wall portion, said member consisting of a metal lic material substantially of nickel. 2. A mercury-cathode tube comprising an~ en velope having a wall portion of mercury-resistant metal forming part of the bottom thereof, elec to the bottom of member I and serving to supply ‘ trodes within said envelope including a mercury cathode within the bottom part, and a massive current to cathode 3. Centrally disposed in the mercury'cathode 3 is an anchoring member I6. According to the 20 invention, I form member I6 of a metal or metal `alloy Whose “dissolving speed in mercury” dur ing the discharge of the discharge current is at `the utmost T‘mfand preferably about 1/40, of that of copper, :and which'amalgamates better Vthan does iron or molybdenum. As a suitable material for this purpose I prefer to use nickel or an --alloy substantially constituted by this metal. To insure good dissipation of heat from mem berV I6, the entire lower surface thereof is in di rect _metallic contact with the bottom of the memberwl, and for instance, Welded thereto. The member I5, which is of large size and of a good .heat~.transmitting material, such as copper, is secured, for instance welded, to the lower surface of .member I land thus aids in the dissipation of .heat from the anchoring member I6. As shown in Figure 1, member I6 is shaped as a disc; -however it maybe given various other :40 shapes, for instance asa ring 23, as shown in Fig. .2. The cathode line inside a ringshaped member,».in contradistinction to that around a disc shaped member, will show a tendency to grow longer as a result of the gradual erosion of the `member so that its current carrying capacity 45 is not impaired with the increase of the age of .the tube. Furthermore, >member I6 may have aroundedor roughened upper surface, and it is sometimes >of advantage to use a porous struc "50 ture. While I have described my invention in con nection with speciñcexamples and applications, I doV .not Wish >to be limited ythereto but desire cathode-spot anchoring member of nickel partly within said mercury cathode and carried by said 20 metal wall portion. 3. Afmercury-cathode tube comprising an en~ veloperhaving a wall portion of mercury-resistant metal forming part of the bottom thereof, elec trodes within said envelope including a mercury cathode within the bottom part, and a massive 25 cathode-spot anchoring member partly within said mercury cathode and secured to said metal wall portion in good heat-transferring relation ship, said member consisting of a metallic ma terial substantially of nickel. 30 4. A mercury-cathode tube comprising an en velope having a wall portion of mercury-resistant metal forming part of the bottom thereof, means for artificially cooling said metal wall portion, electrodes ~within said envelope including a mer cury cathode Within the bottom part, and a mas 35 sive cathode-spot anchoring member partly Within said mercury cathode and secured to said wall portion in good heat-transferring relationship, said member consisting of a lmetallic material 40 substantially of nickel. .5. A mercury~cathode tube comprising an en velope having a wall portionof mercury-resistant metal forming part of the bottom thereof, elec trodes withinvsaid envelope including-a mercury 45 cathode within the bottom part, and a massive cathode-spot anchoring vmember partly within said mercury cathode andcarried by said metal ,Wall portion, said member having an annular shapeand consisting of a metallic material sub 50 stantially of nickel. rI'OM JURRIAANSE.