US 2200940 A
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May-l4, 1940- w. UYTERHOEVEN ETAL GASEOUS ELECTRIC DISCHARGE DEVICE Filed April 18, 19:55
' INV ENTbRS ATTORNEY Patented May 14, 1940 UNITED STATES PATENT OFFICE GASEOUS ELECTRIC DISCHARGE DEvIcE Application April 18, 1935, Serial No. 17,082 In the Netherlands April 19, 1934 3 Claims.
The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to such devices the container of which has two or more parallel parts and which is at an elevated temperature, such as 200 C. or more, during the operation of the device. Such lamps usually contain the vapor of a diflicultly vaporized metal, that is a metal the vapor pressure of which at a temperature of 200 C. is less than 1 mm., such as sodium,-
cadmium, magnesium, or zinc.
In the United States Patent Number 2,001,511, granted May 14, 1935, a lamp unit is disclosed which comprises a gaseous electric discharge lamp device the. elongated container of which is bent into four parallel, adjacent parts. The advantage in the structure is that it is more easily mounted in lamp units comprising the lamp and a heat conservator thereof. we have observed that when the ends of such folded lamp containers are rigidly fastened in a common base the container is apt to break due to the expansion and contraction thereof under the service condi tions of the lamp.
The object of the present invention is to provide a lamp unit comprising a heat conservator and a gaseous electric discharge device having a folded container in which there is no possibility of the lamp container breaking due to the expansion and contraction thereof under service conditions of the lamp. Another object of the invention is to provide a lamp unit of the above type which is easily assembled and taken apart. Another object of the invention is to facilitate the starting of the gaseous electric discharge lamps in such lamp units. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description.
The invention attains its objects by fastening the supporting base for the container of the gaseous electric discharge lamp at a part of said container between the ends thereof, leaving the ends of the container free to move when the container expands and contracts under the service conditions of the lamp, and by utilizing an element of the base as an auxiliary electrode to facilitate the starting of the lamp.
In the drawing accompanying and forming part of this specification an embodiment of the invention is shown in which.
Fig. 1 is a front elevational partly sectional view of a lamp embodying the invention,
Fig. 2 is a sectional view along the line 2-2 of Fig. 1, and
Fig. 3 is a side elevational, partly sectional view of the lamp shown in Fig. 1.
Like numbers denote like parts in all the figures.
Referring to the drawing the new and novel lamp comprises an elongated container bent into four parallel parts and having an electrode 3, l sealed into'each end thereof. Each of said electrodes 3, l consist of an element 3 which is electron emittingwhen heated and which consists of a coiled tungsten filament having another filament, such asa tungsten or a nickel filament, wrapped around it. Said element 3 is coated or impregnated with an electron emitting material, such as barium oxide. Said element 3 is surrounded by anopen ended, sheet metal cylinder 4 which is electrically connected thereto. Said container I has a gaseous atmosphere therein consisting of a mixture of a starting gas, such as a mixture of neon to which is added a small percentage of argon, and a metal vapor, such as sodium vapor. A small quantity of sodium is introduced into said container I during the manufacture of the lamp which is the source of the sodium vapor during the operation of the lamp. The container I must be at an elevated temperature during the operation of the lamp in order to obtain an effective metal vapor pressure therein and a heat conservator, such as a double walled jacket having the space between the walls thereof evacuated, which conservator surrounds the lamp container and reduces the heat losses therefrom, is useful for this purpose. During the operation of the lamp the light emitted thereby is rich in rays characteristic of the sodium vapor.
A base 5 of heat resisting, insulating material, such as porcelain, is fastened to a curved part of the container I at approximately the curved mid-part of said container I. The base 5 is fastened to said container I by the clamping element 6, I, I. The part 6 of said clamping element 6, I, 8 is a rigid body of conducting material,' nickel, for example, which fits the curvature of the container I on one side thereof. The other side of said part 6 fits into an indentation in the base 5. The part 1 of the clamping element 6, I, 8 is flexible and is attached at one end thereof to the part 8. The other end of said flexible part I is removably attached to the other end of the part 6 by the screw bolt 8. Said part 1 passes around the container I and clamps said container I against said part 6. A thin layer of heat resisting, insulating material, such as asbestos, is interposed between the container I and said part I. Said part 6 has fastenedthereto a metal pinIO which passes through an opening in the base and which is threaded. Said clamping element 6, I, 8 is fastened to said base 5 by the nut II which pulls up and holds the pin I0 in position on the base 5.
The element 6 also serves as an auxiliary electrode having a capacitive action for facilitating the starting or the gaseous electric discharge device. The pin I 0 is a contact element for the auxiliary electrode 6. i In order to avoid the presence of air bubbles between the auxiliary electrode 6 and the wall of the container I the part 0! the wall covered by said electrode 6 is coated, by methods well known in the art, as by the Schoop method. for example, with a thin layer I3 of metal (Fig. 1). This avoids the creation of an electric field in the space between the layer l3 and the electrode 6 and prevents ionization of the air in this space.
The electrodes 3, 4 of the lamp are connected by flexible leads I4 to the contact pins 12 of the base 5. Said leads H are removably connected to said contact pins I2. The flexible leads I permit the ends 2 of the container I to move when the container I expands and contracts under the service conditions or the lamp.
A suitable heat conservator (omitted from the drawing for simplicity of illustration) is a double walled jacket surrounding the container I and having the space between the walls thereof evacuated. Said conservator is provided with a supporting ring of heat resisting material, such as porcelain, cemented thereto and which ring makes a tight mechanical joint with the shoulder of the base 5.
The lamp unit is easily assembled by inserting the container l in the clamp 6, I, 8, tightening the bolt 8, attaching leads I 4 to the pins I2 and slipping the supporting ring of the heat conservator onto the base 5. The lamp unit is just as easily taken apart. The ends 2 of the lamp device are free to move when the container I expands or contracts so that the danger of the container walls breaking is obviated. The lamp is quickly started into operation by the auxiliary electrode 6 mounted along the discharge path between the electrodes 3, 4.
While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details'of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention.
What we claim as new and desire to secure by Letters Patent of the United States is:
1. A lamp unit comprising in combination a gaseous electric discharge lamp device, a base therefore, and a clamp of electrically conducting material, said lamp comprising an elongated, curved container, said base being removably fastened to said container between the ends of said container by said clamp, the ends of said container being free to move with respect to the other elements of said lamp unit.
2. A lamp unit comprising in combination a gaseous electric discharge lamp device, a base therefor, and a clamp of electrically conducting material, said lamp comprising an elongated, curved container, said base being removably fastened to said container between the ends of said container by said clamp, said clamp being an auxiliary electrode to facilitate the starting or said lamp, and a body of heat insulating material interposed between the movable part 01 said clamp and said container, the ends of said container being free to move with respect to the other elements of said lamp unit.
3. A lamp unit comprising in combination a gaseous electric discharge lamp device and a base therefor, and a clamp of electrically conducting material, said lamp comprising an elongated, curved container, said base being removably fastened to said'container between the ends of said container by said clamp, said clamp being an auxiliary electrode to facilitate the starting of said lamp, said container having a metal coating on the outer surface thereof in contact with the immovable part of said clamp, the ends of said container being free to move with respect to the other element of said lamp unit.
JOHANNES P. M. MUTSAERS. WILLEM UYTE'RHOEVEN. CORNELIS VERBURG. PIE'I'ER SCHOUWS'I'RA.
CERTIFlCATE OF CORRECTION.-
,Patent No. 2,200,9LLQ. u may 1h, 19h0.
WILLEM UYTERHOEVEN, ET AL.
It is hereby certified that errorappears in the printed specification of the above numbered patent requiring correction as follows: Page 1 first column, line 8, for the'vilord "vaporized" read --vaporiz'gble--; page 2, second column, line 15, claim 5, for "element" read -elementS- and may the saiid Letters Patent shculd be read with. this correction,therein that the same may conform to the record-of the case in the Patent Office.
Signed and sealed this 14.1:11 day of March, A, D. 19141.
Henry Van Arsdale, (86211)" Acting Commissioner cf Patents.