RU1780125C - High pressure sodium lamp - Google Patents

Abstract

Usage: in the electrical industry, in sodium gas-discharge high-pressure lamps. The purpose of the invention is to reduce the ignition voltage, increase the reliability of ignition of high pressure sodium lamps during the service life and the manufacturability of their manufacture. The inventive high pressure sodium lamp contains an arc discharge tube made of alumina with ceramic plugs, hermetically sealed to the ends of the tube, the main electrodes, the inputs of which pass in the Central part of the ceramic plugs, an auxiliary trigger electrode passing through the ceramic plug, trigger a conductor located along the outer surface of the discharge tube, while the auxiliary starting electrode is electrically connected through a resistor to the opposite main electro y, a conductor although the starting point would be to lamp ignition are electrically connected to the main electrode. The starting auxiliary electrode and the starting conductor are made by applying a conductive metallized coating, consisting, for example, of 70-95% metal tungsten and 5-20% yttrium oxide, on the inner and outer part of the discharge tube. The coating is applied in the form of a cylinder, the height of which reaches the height of the proximal main electrode, and the application height on the outer part of the discharge tube reaches the height of the opposite main electrode. In order to ensure reliable electrical contact of the supply metal conductors with the auxiliary starting electrode and the conductor and to control the electrical parameters of the burner, an annular conductive coating is applied on the outer surface of the discharge tube in the area of the main electrode, the height of which is 0.3-1.0 diameters discharge tube. 2 s.p. piano, 4 ill. • h * 'ёV4 00 OUsl > &

Description

The invention relates to the electrical industry and can be used in the manufacture of high pressure sodium discharge lamps.

The ignition voltage of high-pressure sodium lamps is much higher than the mains voltage, therefore, for

The ignition of such lamps uses non-continuous pulse ignition devices generating a voltage pulse of the order of 2.5-4.5 kV.

The purpose of the invention is to increase the nfiAexibility of ignition of sodium amp.

pressure over the life cycle and manufacturability of their manufacture.

In a high-pressure sodium lamp containing an arc discharge tube made of alumina and having ceramic plugs that are hermetically soldered to the ends of the tube, the main electrodes, the inputs of which pass in the central part of the ceramic plugs, have an auxiliary electrode and a starting conductor, made as integrated by applying a conductive strip to the inner and outer surfaces of the discharge tube and along the shortest path. The application height on the inside of the discharge tube reaches the height of the proximal main electrode, and the application height on the outside of the discharge tube reaches the height of the distant main electrode.

Thus, the proposed design of the starting auxiliary electrode simultaneously functions as an internal starting auxiliary electrode, which allows ionizing the atmosphere inside the arc discharge tube and contributing to the appearance of the arc discharge and the function of the starting auxiliary conductor, which facilitates the propagation of the discharge along the discharge tube to another main electrode . The auxiliary trigger electrode is applied to the inside of the discharge tube in the form of a cylinder, the height of which reaches the height of the proximal main electrode, which ensures the necessary gap between the main and auxiliary trigger electrodes during the burner manufacturing process.

The starting auxiliary electrode is made, in particular, in the form of a metallized coating based on tungsten-yttrium paste with a tungsten content of 70-95% and yttrium oxide 5-30% by weight. The very small thickness of the metallized coating (3-5 microns) makes it possible to obtain a vacuum-tight weld of metal into ceramics, which reliably works at high temperatures. The presence of yttrium VaO3 oxide in the metallized coating allows one to obtain good emission characteristics necessary for ionizing the atmosphere and causing a glow discharge inside the burner between the main and auxiliary starting electrodes. To facilitate reliable electrical contact of the supply metal conductors with the auxiliary start electrode on the outer surface of the discharge tube in the area of the main electrode

an annular conductive coating may be applied.

A feature of its use in a sodium bath is that in order to reduce the energy loss at the end of the discharge tube and thereby control the voltage on the lamp, the height of the annular conductive coating is 0.3-1.0 times the diameter of the discharge tube.

Fig. 1 schematically shows a high pressure sodium lamp, general view; Figures 2 and 3 show a discharge tube of a high pressure sodium lamp; figure 4 is a graph of the voltage on the lamp on the ratio of the height of the annular conductive coating on the outer surface of the discharge tube to the diameter of the discharge

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The high-pressure sodium lamp (Fig. 1) contains a cap 1, a flask 2, an arc discharge tube 3 made of alumina, consisting of an elongated hollow body 4 having ceramic plugs 5 sealed to the ends of the hollow body 4 enclosing discharge-supporting filling consisting of sodium or sodium vapor and mercury vapor, as well as an inert ionizable ignition gas such as xeno.n under a pressure of from 20 to 350 mmHg, art. Inside the arc discharge tube 3, near its ends, are the main electrodes 6 and 7, connected to the bushings 8, which pass through the ceramic plugs 5 in their central part being hermetically sealed to them. Inside and outside the tube 3 is a continuous coating 9.

The light-transmitting and protective outer bulb 2 covers the arc discharge tube 3, while inside the outer bulb 2 there is a frame 10 that holds the arc discharge tube 3 in a predetermined position and serves as a current supply to the inlet 8. A threaded base 1 is connected to the outer bulb, intended for connection to an energy source.

As shown in Fig. 2, a conductive metallized coating 9 is applied to the inner and outer part of the discharge tube 3, which, together with the discharge tube 3 and the ceramic plug 5, forms a vacuum, but a tight seal. The metallized coating 9 is applied by one of the methods, for example, by applying tungsten-yttrium paste to a pre-sintered discharge tube 4 of aluminum oxide and then sintering it in a hydrogen medium at 1750-1900 ° C, while the coating thickness is 3-5 microns. The coating composition (70-95% metallic tungsten and 5-30% yttrium oxide) is selected from the condition of obtaining the necessary density, conductivity and emission properties. The inner part of the conductive metallized coating 9 is applied to the height of the electrode 6 in the form of a cylinder, and the outer part of the coating is applied up to the height of the electrode 7, which allows to have the lowest ignition voltage.

In order to ensure reliable electrical contact of the supply metal conductor 11 (connected through a resistor 12 to the frame 10), a metallic conductive coating 9 is provided on the outer surface of the discharge tube 3 in the area of the main electrode 6, an annular conductive coating 13 is applied (Fig. 3).

Experiments were carried out regarding the variation in voltage on the lamp depending on the height of the annular conductive coating 15.

In FIG. a graph illustrating the dependence of the voltage on the lamp on the ratio of the height of the annular conductive coating 13 to the diameter of the discharge tube 3 (l / d). As shown in figure 4, in the absence of an annular coating 13, the voltage on the lamp is 60 V, and with a coating height of 1.0 diameter of the tube 3 is 110 V.

The annular conductive coating 13 is electrically connected through the conductive metal conductor 11 and the resistor 12 to the input 8 of the main electrode 7. The resistance of the resistor 12 is 20 kΩ, which prevents a significant current from passing through the conductive metallized coating 9.

High Pressure Sodium Lamp Features:

Lamp power250 W

The voltage on the lamp is 115V. The main parameters of the burner are: the outer diameter of the ceramic tube is 8.8 mm; the wall thickness of the tube is 0.8 mm; the outer diameter of the spiral of the main electrode4;

mercury - 20 kg xenon - 20 mmHg Main parameters of the starting auxiliary electrode:

metal configuration, 1izirovanny coating in the form of a cylinder on the inner surface of ceramic

T2 mm high tubes 4 microns thick

coating composition 75% W + 25% U20z Basic parameters0 meters of the starting conductor:

the configuration is a metallized coating in the form of a strip on the outer surface of a ceramic.

tube

thickness 4 microns

width0.5mm

coating composition 75% W + 25% 0 Y203 0 Resistance

limiting resistor 20 kOhm

The main parameters of the annular 5 conductive coating:

ring configuration on the outer surface of the ceramic tube in the 0 zone of the main

electrode

thickness 10 μm

height 7 mm

Lamp voltage 5 V 190 V

The proposed sodium lamp operates as follows.

The mains voltage through the cap 1 and the supply conductors is applied to the 0 main electrodes. In this case, the potential from the electrode 7 is supplied through the resistor 12 to the starting auxiliary electrode. Between the main electrode 6 and the inner part of the starting auxiliary 5 electrode, a glow discharge arises which ionizes the filling of the burner. Resistor 12 limits the discharge current and protects the burner from destruction. The presence of yttrium oxide in the coating constituting the starting auxiliary electrode makes it possible to ensure the occurrence of a glow discharge throughout the entire service life. The execution of the internal part of the starting auxiliary electrode in the form of a cylinder 5, which reaches the height of the main electrode, automatically ensures the optimal gap between the auxiliary and main electrodes when assembling the burner. The outer part of the starting auxiliary electrode, which is under the potential of the main electrode 7, helps to spread the main discharge along the burner. As the conductive plasma propagates from the main electrode 6 to the main electrode 7 between the latter, the main arc is ignited, the parameters of which are determined by ballast. The presence of an annular conductive coating with a height of 7 mm on the outer surface of the burner in the area of the main electrode makes it possible to ensure reliable electrical contact of the starting auxiliary electrode with the supply conductors and to insulate the end of the burner in order to bring the electrical parameters to nominal values, since the coating acts as a thermal screen.

The use of a high-pressure sodium lamp of the proposed design improves the reliability of its ignition without the use of external pulsed ignition devices.

Claims (2)

SUMMARY OF THE INVENTION 1. A high-pressure sodium lamp containing an aluminum oxide discharge tube having ceramic plugs tightly attached to the ends of the tube, main electrodes, the inlets of which pass in the central part of the ceramic plugs, an auxiliary starting electrode, passing at least through one ceramic plug and made of a material inert to the discharge-supporting filling of alkali metals or alkali metals, mercury and inert gas, a starting conductor located lengthwise outer surface of the discharge tube, wherein an auxiliary starting electrode is electrically connected via a resistor to opposite to the main electrode, and the starting conductor, at least at the time of ignition of the lamps, is provided with means for electrically connecting to the main electrode, characterized in that, with In order to increase the reliability of ignition during the service life and manufacturability, the auxiliary starting electrode and starting conductor are made in the form of a continuous coating of refractory metals with the addition of heat-resistant emitting materials on the inner and outer surfaces of the discharge tube along the shortest path, and the deposition height on the inner part the discharge tube reaches the height of the near main electrode, and the height of application on the outer part of the discharge tube reaches a height opposite main electrode. 2. The lamp according to 1, characterized in that which, in order to obtain the necessary density, conductivity, and emission properties, the conductive metallized coating consists of 70-95% metallic tungsten and 5-30% yttrium oxide, 3, The lamp according to claims 1 and 2, with the exception that, in order to control the electrical parameters of the discharge tube, an annular coating is made on the outer surface of the discharge tube in the area of the main electrode, the height of which was It is 0.3-1.0 times the diameter of the discharge tube. /ABOUT Fig. /  AT Fie.g U., 5 120 t sh 5070 so fifty / 1,5 w .5 W Qa2.