DE656438C

DE656438C - Electric discharge tubes with steam that are difficult to evaporate metals used for light emission

Info

Publication number: DE656438C
Application number: DEN35660D
Authority: DE
Inventors: Mari Johan Druyvesteyn; Pieter Schouwstra
Original assignee: Philips Patentverwaltung GmbH
Current assignee: Philips Intellectual Property and Standards GmbH
Priority date: 1933-08-29
Filing date: 1933-08-29
Publication date: 1938-02-04
Also published as: BE404539A; FR776840A; NL40363C

Description

Das Patent 652752 betrifft eine mit einem entlüfteten Raum umgebene, insbesondere für Lichtausstrahlung dienende elektrische Entladungsröhre, die den Dampf eines schwerflüchtigen Metalls, wie Natrium, Cadmium, Thallium, d. h. eines Metalls enthält, dessen Dampfdruck bei 200⁰ C nur einen Bruchteil eines Millimeters beträgt, und bei der dieser Raum zwischen den Wänden einer doppelwandigen Hülle ausgebildet ist, die die Röhre mit einem Luft enthaltenden Zwischenraum umschließt. Es ist nicht immer erforderlich, die Entlüftung so weit durchzuführen, daß ein absolutes Vakuum erreicht wird. Unter Umständen ist es möglich, eine kleine Gasmenge, z. B. Luft, im Raum zurückbleiben zu lassen. Dieser entlüftete Raum hat' eine wärmeisolierende Wirkung, durch welche die Wärmeabgabe der Entladungsröhre herabgesetzt wird und das Erreichen eines höheren Dampfdruckes in der Röhre erleichtert, während die zwischen der Röhre und der Hülle vorhandene Luft einen Temperaturausgleich der Röhrenwand bewirkt.Patent 652752 relates to an electric discharge tube surrounded by a ventilated space, in particular used for light emission, which contains the vapor of a non-volatile metal such as sodium, cadmium, thallium, ie a metal whose vapor pressure at 200 ⁰ C is only a fraction of a millimeter, and in which this space is formed between the walls of a double-walled envelope which encloses the tube with a space containing air. It is not always necessary to ventilate far enough to achieve an absolute vacuum. It may be possible to use a small amount of gas, e.g. B. to leave air in the room. This ventilated space has a heat-insulating effect, by means of which the heat output of the discharge tube is reduced and makes it easier to achieve a higher vapor pressure in the tube, while the air present between the tube and the envelope effects a temperature equalization of the tube wall.

Es hat sich nunmehr gezeigt, daß die Temperatur der Entladungsröhre und infolgedessen der Druck des Metalldampfes stark von Veränderungen in der Umgebung, in der die Entladungsröhre mit der Hülle angeordnet ist, abhängig sein kann. Ein Fallen der Umgebungstemperatur verursach? ein Fallen der Temperatur der Außenwand der Hülle, was z. B. auch . durch Regen oder Wind herbeigeführt werden kann. Ein Fallen der Temperatur der Außenwand der Hülle verursacht weiterhin ein Fallen der Temperatur der Innenwand und der Entladungsröhre und infolgedessen auch ein Fallen des Metalldampfdruckes. Ebenso hat eine z. B. durch eine allgemeine Temperatursteigerung verursachte Steigerung der Temperatur der Außenwand der Hülle eine Zunahme der Röhrentemperatur und des Dampfdruckes zur Folge. Diese Temperatur- und Druckschwankungen haben im allgemeinen einen ungünstigen Einfluß auf die Eigenschaften der Entladungsröhre, z. B. auf die Intensität des durch die Röhre ausgestrahlten Lichtes.It has now been found that the temperature of the discharge tube and, consequently, the pressure of the metal vapor depends greatly on changes in the environment in which the discharge tube is arranged with the envelope, may be dependent. Get an idea caused by the ambient temperature? a drop in the temperature of the outer wall of the Shell, what z. Belly . can be caused by rain or wind. Get an idea the temperature of the outer wall of the envelope also causes the temperature to drop of the inner wall and the discharge tube and, as a result, a drop in metal vapor pressure. Likewise, a z. B. caused by a general increase in temperature increase in the temperature of Outer wall of the shell leads to an increase in the tube temperature and the vapor pressure. These temperature and pressure fluctuations generally have an unfavorable influence on the properties of the discharge tube, z. B. on the intensity of the light emitted through the tube.

"') Von dem Patentsucher sind als die Erfinder angegeben worden:"') The patent seeker indicated the following as the inventors:

Mari Johan Druyvesteyn und Pieter Schoiiwstra in Eindhoven, Holland.Mari Johan Druyvesteyn and Pieter Schoiiwstra in Eindhoven, Holland.

Claims

The invention aims to eliminate these drawbacks and the discharge tube less so to make dependent on the state of the environment.

According to the invention, the ge * called tubes for this purpose in dciij vent surrounding the discharge tube; ^ th room one or more permeable to light, e.g. B. arranged glass screens. It has been found that the discharge tube is less affected by temperature fluctuations the outer wall of the shell becomes dependent.

In the drawing, an embodiment of the invention is shown as an example.
The discharge tube 1, which is used for emitting light and which is illustrated in the figure, has a helically wound hot cathode, which is illustrated in a side view, and two ring-shaped anodes 3; it contains a lot of noble gas, e.g. B. Neon, under low pressure and a lot of sodium. The sodium vapor participates effectively in the emission of light when it has reached a sufficiently high pressure.

The heat output of the discharge tube is through the one surrounding the discharge tube double-walled glass envelope 4 reduced, in which the between the outer wall 5 and the inner wall 6 formed space is vented. The discharge tube and the envelope can be equipped with bases with which they are attached to a fitting can. By this base or by other means, the space between the Tube and sheath, completed at the end. Between the walls 5 and 6 is a glass ■ arranged screen 7, which by means of the glass rod 8 on the inner wall of the shell is attached. The screen 7 is thus located in the area surrounding the discharge tube ventilated space. It has been shown that the temperature of the discharge tube 1 and consequently the pressure of the sodium vapor is less affected by the temperature fluctuations the outer wall 5 is dependent. Instead of an umbrella, if desired several screens can also be accommodated in the ventilated space, through which the Independence from the vapor pressure of the outside environment is increased.

PA T E N T Λ N S P R U C H ".PA T E N T Λ N S P R U C H ".

. Surrounded by a ventilated room, especially one used to emit light electric discharge tube with vapor of a non-volatile metal, such as sodium, in which this space between the walls of a double-walled envelope is formed, which the tube with an air-containing space encloses, according to patent 652 752, characterized in that in which the Tube enclosing ventilated space one or more translucent, approximately glass screens are arranged.

1 sheet of drawings