JPS59108258A - High pressure sodium vapor lamp - Google Patents

Abstract

PURPOSE:To enable the breakage of a luminous tube to be prevented when an excess current flows in the lamp by using a conductive wire having fusing function in special relation to the starting rare gas sealed in the luminous tube, as the lead wire to be connected to the cap metal led out from the external tube stem. CONSTITUTION:Wells 10, 11 are connected to the cap metal 4. That is, wells 10, 11 are connected to seal-in wires 20, 21 made of dumet wires etc. At least one of lead wires 22 and 23 has fusing function, not only this wire is built by a conducting wire of melting point less than 2,000 deg.C, but also is built to satisfy logP<=0.4(IL/S)+0.7 in case of sectional area of this conducting wire being Smm.<2>, lamp current being IL(Ampere) and sealed-in pressure of starting rare gas sealed in the luminous tube being P(Torr). Through the abovementioned process, the external lead wire is fused off and breakage of the luminous tube can be prevented in case of an excess current flowing in the lamp.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a technology for preventing bursting of arc tubes in high-pressure sodium lamps.

[Technical background of the invention and its problems]

In general, high-pressure metal vapor discharge lamps do not have the ability to limit current by themselves, so they are used in combination with a ballast as a current limiter. Stabilizers are often made up of a single choke coil, which is made by winding a metal wire coated with insulation in multiple layers around an iron core, and other devices that also use capacitors are also used.

By the way, the lifespan of a ballast is usually 8 to 10 years, and the main cause of the lifespan is a decline in current limiting function due to deterioration of the insulator. In particular, high-pressure sodium lamps have a high starting voltage, so the high-pressure starting voltage is supplied from a ballast or a pulse generator housed inside the lamp's outer bulb. Because of this high voltage and z, it tends to accelerate the deterioration of the ballast's insulation compared to high-pressure water plate lamps, metal halide lamps, etc. The IK'2 edge of the starting ballast may be forcibly destroyed by the high voltage pulse.

When the lamp regulator loses its current-limiting function at the end of its life or for other reasons, a large amount of current fx flows through the lamp. f) As a result, the lamp input applied to the arc tube rapidly increases, causing the arc tube to rupture as the pressure of the inclusions inside the arc tube increases rapidly, and further (even rupturing the tube, causing damage to the lamp itself or to debris). I'm worried about falling, etc.

In order to prevent such danger, Japanese Patent Application Laid-Open No. 51-9618
A method such as that shown in "Publication No. 6" has been developed. In other words, this device has a conductive wire with a fuse function recessed in a part of the lead wire from the steno terminal of the outer tube to the eyelet terminal of the base, and the above fuse ↑f' The conductive wire with 1 function instantly melts 1 to 1 to prevent the arc tube from being damaged.

[7 However, when selecting a fuse that does not have such a fuse function, it is not possible to make a judgment based solely on its fusing ability against overcurrent.] At high pressure sodium lamp 0, It is necessary to consider the relationship with the gas pressure of the starting rare gas inserted into the arc tube. That is, when an overcurrent is applied to the arc tube, the temperature inside the arc tube rises rapidly, and the gas pressure inside the tube also increases accordingly. As the gas pressure rises, the wall of the arc tube becomes unable to withstand it, resulting in cracks and rupture.

The degree to which the gas pressure rises depends on the relationship between the magnitude of the input lamp current and the sealed gas pressure. However, since the charging pressure of the noble gas for starting high-pressure sodium lamps is a factor that determines the rung efficiency, the charging pressure may be 0 depending on the rung rating value, or may differ even if the rating is the same. The function cannot be selected simply by the fusing ability based on the overcurrent value.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its object is to connect a lead wire led out from the stem of the outer tube and connected to the cap with a starting noble gas sealed in the arc tube and a predetermined amount. It is an object of the present invention to provide a high-pressure sodium lamp that uses a conductive wire having a related fuse function and can prevent the arc tube from bursting when an excessive current flows through the lamp.

[Summary of the invention]

In other words, the present invention provides that at least one of the lead wires led out from the stem of the outer tube and connected to the
It is composed of a conductive wire with a melting point below 0°C, and the cross-sectional area of the conductive wire is 5 (-), the Lang current is ■ (An 4 A), and the pressure of the starting rare gas in the arc tube is P. (Tor
r) It is characterized in that it satisfies (17) tog P≦0.4 (/S) + 0.7 in the case of L.

[Embodiments of the invention]

j:, j An embodiment of the sewage invention will be described based on the drawings.

In the figure, 1 is an outer tube, and the neck portion 2 is sealed with a steno tube 3. A cap 4, which will be described later, is attached to this stem portion. The arc tube 5 housed in the outer tube 1 is made of a translucent ceramic tube, and has main electrodes 5a and 6b inside both ends.
It is set up oppositely. The arc tube 5 is filled with predetermined amounts of mercury and sodium and a starting rare gas such as xenon gas at a predetermined pressure. The arc tube 5 is supported at both ends by boulders 7a and 7b. In this case, one holder 7a is electrically connected to the main electrode 6a, while the other holder 7b is supported via the insulator 8 with respect to the main electrode 6h. - The holder 7a97b is connected to a support 9 which also serves as a conductive wire, and this support 9 is welded to a well 10 sealed to the stem 3. Note that another well 1 is also sealed to the stem 3, and the other main electrode 6b is connected to this well 1 via an internal lead wire 12.

One end of a proximate conductor 13 is freely supported by the one holder 7a, and the other end of the proximal conductor 13 is supported by the support 9 via a bimetal piece 14. The proximate conductor is brought into contact with or close to the outer surface of the arc tube 5 before starting the lamp, and is separated from the arc tube 5 by thermal deformation of the bimetal piece 14 due to the heat generated by the arc tube 50 after the lamp is lit.

Filament 15s5・J is installed inside outer shell 1 as a starting device.
, and a bimetal switch 16 are housed therein. That is, reference numeral 17 denotes an insulating stand, on which the filament 15 is stretched and supported in a planar shape, and a bimetal switch 16 is disposed facing the filament 15. One end of the filament 15 is connected to the connecting wire 18
is connected to the aforementioned internal lead wire I2, and the other end is connected to one end of the bimetal switch 16. The other end of this bimetal switch 16 is connected to the first port 9 via another connection line 19. Therefore, the filament 15 and the bimetal switch 16 form a series circuit as shown in FIG. 3, and this series circuit is connected in parallel to the arc tube 5. Note that the bimetal switch 16 is a normally closed switch.

The well 10.11 is thus connected to the cap 4 as shown in FIG. Wells 10
．． 11 is a sealing wire 2t made of Dumet wire etc.), 21
These sealed wires 20 and 21 are connected to the external leads ili! j! ,? ,? , 23. One external lead wire 22 is connected to the main body 24 of the base 4, and the other lead wire 23 is connected to the eyelet terminal 25. At least one of these lead wires 22 and 23 has a heating function, and 20
The conductive wire has a cross-sectional area of S (F, 4), a lamp current of I (ampere), and a starting diode sealed in the arc tube 5. When the gas sealing pressure is P (Torr), tog P≦0.4 ('L/ ) + 0.7 ・(
1).

Note that 26 in FIG. 1 is a getter. Further, a high-pressure sodium rung having such a configuration is used by being connected to an AC power source 3 via a choke coil type ballast 30, as shown in No. 30, Z).

The conditions for the lead wire 22 or 23 having the above-mentioned locking function were determined through experiments by the inventors, and the experiments will be explained below.

[Experiment 1] A high-pressure thorium lamp with a rated lamp power WL of 360 watts has a lamp voltage VL of 130 volts and a lamp current I of 3.3 amperes. An experiment was conducted in which the ballast was short-circuited when the lamp was lit in combination with a ballast.In this case, the following three phenomena occurred.

(1) The arc tube ruptures from near the electrode tip to the center.

(2) The arc tube ruptures and the lead wires 22 and 23 melt simultaneously.

(3) The arc tube does not explode, but the lead wires do fuse.

If you connect the lamp directly to the power supply without using a ballast,
The lamp is started by the high voltage pulse of the starting device in the outer tube due to the inductance component of the power supply side, but the phenomena (1) to (3) above occur immediately after starting. These experimental results show that it is possible to melt down the leads ff1p2''2' and 23 sooner than the bursting of the arc tube, and that it is possible to prevent the bursting of the arc tube.

[Experiment 2] Lead wire? 2.The material of 2.9 is nickel (Nl)
Lamps with various cross-sectional areas 5(-) were made using single wires or twisted wires, and tests were conducted by short-circuiting the ballast during stable lighting to examine the extent to which the lead wires were fused and the arc tubes were ruptured. The results are shown in the table below. The lamps used were 180 watts, 360 watts, and 660 watts compatible with mercury lamp ballasts.
Both are filled with xenon gas at 250 Torr as a starting rare gas.

From the results in the table above, it can be seen that even if the cross-sectional area S of the lead wire is increased as the rated power becomes larger in watts, only the lead wire will be fused. This means that if an overcurrent flows, the arc tube may explode due to the speed at which the lead wire heats up and melts, the pressure rises at the charge in the arc tube, and the way thermal shock is applied to the arc tube. Indicates that it is decided whether or not to do so. Generally, large-wattage lamps are designed with a large arc tube shape, and even with the same overcurrent and the same filled gas pressure, it takes longer for a large arc tube to increase the internal pressure than a small one. kaυ
Since the thermal shock per unit area of the arc tube is small, it takes a long time for the arc tube to burst, so even if a lead wire with a large cross-sectional area is used, this +J- wire should be connected first. It is thought that this will lead to melting.

In order to evaluate the results in the table at the same level, when 17- is fused, when / = 4-2, lead wire fusion ■ and arc tube rupture coexist, and when 4<2, arc tube rupture occurs. Can be seen. From this, it can be said that it should be regulated within the range of 17≧4.

The same unusual experiment was carried out at 220 watts and 940 watts.
If 1/≧4, then -1+)-t" was confirmed to be only the melting point III.

In addition, the lead wire must not melt under normal usage conditions, so we performed an overload flashing life test on the lamp in a device with high ambient temperature, and examined the lead bond temperature and oxidation progress. /(20S) It has been confirmed that there are no practical problems.

[Experiment 3] In a 360 Watt high-pressure sodium lamp similar to [Experiment 1], the xenon gas pressure was increased from 50 to 500 (T
A short-circuit test similar to [Experiment 1] was conducted by changing the voltage in the range of (orr). As a result, it has been found that the higher the gas pressure, the smaller the wire diameter must be in order to prevent the lead wire from fusing. The reason for this is that the higher the gas pressure, the faster the gas pressure rises in the arc tube when an overcurrent flows, and therefore it is necessary to melt down the lead wire in a shorter time. So another 180 watts.

Using a 660 watt lamp, we varied the gas pressure to examine how the lead wires fused out, and as in [Experiment 2], we found that the larger the wattage, the larger the wire diameter that remained when the lead wires fused out.

Therefore, using a current density of 4, the relationship with the xenon gas pressure P (Torr) in the case where the arc tube does not burst or crack and only the lead wire is fused is summarized as shown in Figure 4. Is it in Figure 4? The line between tog P = 0.4
(/s) + 0.7, and the region below this silk produces favorable results.

Therefore, it was found that in order to melt only the lead wire, the ampere (/, 4) relationship should be restricted to tag P≦0.4 (/s) + 0.7.

Note that the above formula is based on xenon gas pressure of 50 to 500Tnyr.
However, when the xenon gas pressure is low, the extinguishing pressure becomes effective and the lamp efficiency decreases, and conversely, when the xenon gas pressure is high, the nox voltage required to start the lamp increases. It has been found that the starting performance is deteriorated due to this, so it is practically desirable to set the xenon gas pressure in the range of 100 to 350 Torr.

9 Neon is a mixed gas of xenon and krypton instead of xenon gas as the starting rare gas sealed in the arc tube.
It was confirmed that even if a mixed gas of argon was used, if it was within the range of the above formula, only the lead wire would be blown out.

Furthermore, the material of the lead wire is not only nickel, but also iron, copper, aluminum, or materials with additives added to these materials.
Alternatively, it may be an alloy of these materials, and all of these materials have a melting point of 2000°C or less. Melting point is 20
Temperatures exceeding 00°C are undesirable because of their large electrical resistivity.

The machine lead wires 22 and 23 may be any one of which has the fuse function described above.

〔Effect of the invention〕

As described above, according to the present invention, when an excessive current flows through the lamp, the external lead wire is fused and the arc tube is prevented from bursting. In particular, the lead wire does not even cause cracks in the arc tube because the fuse flE is regulated in relation to the charging pressure of the starting rare gas in the arc tube.

The lead wire that still has a fuse function in the present invention is
Since the entire wire from the stem to the cap is used by replacing the conventional lead wire, it can be assembled by the same connection work as the conventional +7- wire, compared to the case where only a part is replaced with a heat wire. The number of work hours is reduced, and the reliability of connections at connection points is also improved.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; Fig. 1 is a block diagram showing the entire high-pressure sodium lamp, Fig. 2 is a block diagram showing a part of the main part in section, and Fig. 3 is a circuit diagram in use. Figure, 4th
The figure is a characteristic diagram. 1... Outer tube, 3... Stem, 4... Cap, 5...
・Earth tube, 6a96°b...Main electrode, 22, 2.9
···Lead. Applicant's agent Patent attorney Suzue Takehikohiko 1 figure: + 2 do 1 25 31st medical doctor 1 'jIP4 figure I/) (chonbe 1/mrn') Procedural amendment Showa I, 48. G, -% Director of the Japan Patent Office Kazuo Wakasugi 1. Indication of the case Patent Application No. 1987-218555 2. Name of the invention High-pressure sodium lamp 3. Relationship with the Nagisa case to be amended Patent applicant (307) Tokyo Shibaura Electric Co., Ltd. Co., Ltd. 11, Agent (5, Amendment No. 1 Specification 7, Contents of Amendment (1) Page 11 of the specification attached to the application is attached to Attachment 11)
Correct as per page. (2) Also in the specification, page 12, line 18.
Shellfish on the J'lO line), ``Any land is I/S ≥ 4
If only the lead wire is fused, and 1/S = 4 to 2," was replaced with "If all lamps have I/Ei≧4#.
In case of 3, only the lead wire is fused and 1/S = 4.2
``In the case of ~2''. (3) Also in the specification, page 13, line 2 [,
The third and fifth lines each say "1/8≧4", which should be corrected to "I/8≧4.3".

Claims (1)

[Claims] A high-pressure sodium lamp in which mercury, sodium, and a starting rare gas are sealed in an arc tube made of translucent ceramic, and the tube is housed in an outer tube with a cap attached to one end. At least one of the lead wires led out from the stem and connected to the base is heated to 2000°C.
It is composed of a conductive wire with the following melting point, the cross-sectional area of this conductive wire is S (m4), the lamp current is I (ampere), and the pressure of the starting rare gas sealed in the arc tube is P. (Torr), tag P≦0.4
(/S) A high-pressure sodium lamp characterized by satisfying +0.7.