JPS5882453A - Metal vapor electric-discharge lamp - Google Patents

Abstract

PURPOSE:To prevent any heat-responsive switch from being overheated, and prevent any thermal deterioration of the switch by shielding radiation heat, which is discharged from an emission tube during lighting, by interposing a heat-shielding member between the emission tube and the switch. CONSTITUTION:Since radiation heat discharged from an emission tube 2 during lighting is shielded by a ceramic-coat current-limiting resistance 11, a bimetal switch 9 is not excessively heated, and the degree to which a bimetal piece 9c is softened due to its overheat fatigue is reduced. As a result, a movable contact 9d securely touches and separates from a fixed contact 9a, and there is no possibility that the function of the bimetal switch 9 is deteriorated during the whole life of the lamp.

Description

Detailed Description of the Invention (Technical Part of the Invention) The present invention relates to a metal vapor discharge lamp in which a starter device and a thermally responsive switch are incorporated together with an arc tube in an outer bulb. (Description of Prior Art) Generally, metal vapor discharge lamps are Although a starting device is required for starting, recently there is already known a rung in which the starting device is built into the outer bulb along with the arc tube.

A conventional metal vapor bronze electric lamp of this type with a built-in starting device is shown in FIGS. death,
The arc tube 2 is held within the outer tube 1 by means 4-)g and 7.

Inside the outer tube 1, on the base 8 side, there is a normally closed bimetal switch 9 as a thermally responsive switch, and a starting device! A lighting tube 10 and a current limiting resistor 11 are accommodated. Although not shown, the current limiting resistor 11 is formed into a plate shape by covering the outer surface of a resistor with a heat-resistant insulator such as ceramic. The bimetal switch 9 is mechanically supported by the ceramic-coated plate-like current limiting resistor 11.

As shown in FIG. Connected to electrode 3. Lighting tube 10 ha/-)
It is connected to the main electrode 4 via 6. and main electrode 3
and 4 are sealed to the stem 13 and connected to the base 8 and the terminal 16 via nine lead wires 14 and 16, and are connected to the power source 18 via the ballast 12 shown in FIG.

In such a discharge lamp, when voltage is applied through the ballast 11, the normally closed bimetal switch 9 is closed, so the lighting tube 10. No current flows through the bimetal switch 9 and the current limiting resistor 11, and the glow lamp 10 is activated. A medium pulse voltage generated from the ballast 1r (due to the switching current of the lighting tube 10) is applied to the main electrode 3.4, the main electrode 4, and the auxiliary electrode S. This starts the arc tube 2.
When the arc tube 4 starts, the heat generated by the arc tube 40 causes the outer tube 1 to
The temperature inside rises, and this heat opens the normally-closed inotal switch 9, preventing current from flowing to the lighting tube 10.Thus, while the arc tube 20 is lit, the lighting tube 10 The operation of the lamp is stopped to preserve the lighting tube 10 and to prevent unnecessary voltage from being applied to the arc tube 2.

As described above, the normally closed bimetal switch 9 is opened by the heat generated from the arc tube 2, so it is always heated while the arc tube 2 is lit. The bimetal switch 9 may become fatigue-softened due to the heating during the lifetime of the rung, which lasts for several thousand hours, and the bimetal contact may not be able to completely return and close.

For rated cuff rungs of 00 watts to 1 kilowatt or more, the neck of the outer tube 1 is long, so the normally closed bimetal switch 9 is housed in the neck and the luminous tube 2 is closed.
Although it is not impossible to avoid excessive heating during lighting by keeping it at a distance of at least som from
In medium-sized rungs of 00 watts and 400 watts, the distance between the arc tube 2 and the bimetallic switch 9 was small, so there was a drawback that thermal deterioration of the 9-metal was significant.

(Object of the Invention) The present invention was developed based on the above-mentioned circumstances, and its purpose is to melt and prevent deterioration of a thermally responsive switch due to heat dissipation from the arc tube.

The object is to provide a metal vapor discharge lamp that can operate reliably over its entire life.

(Summary of the Invention) That is, the present invention provides an early stage of the thermal response switch by interposing a fast heating element between the arc tube and the thermal switch to prevent the radiant heat from the arc tube from directly hitting the thermal switch. This prevents thermal deterioration.

(Example of the invention) An embodiment of the present invention is shown in FIGS. 3 and 4 below.

I will explain based on this.

This embodiment is the same as the conventional FIG. 2 in terms of circuit configuration, and most of the mechanical configuration is the same as that in FIG. 1, so it is the same as FIGS. The parts will be given the same numbers and their descriptions will be omitted.

This embodiment differs from FIG. 1 in that the normally closed/4-metal switch 9 as a thermally responsive switch and the ceramic plate-like current limiting resistor 11 are placed upside down. In other words, the normally closed metal switch 9 is mechanically attached to the ceramic-coated plate-like current-limiting resistor 11 as described above, and is knitted with these, but it is turned upside down. By attaching the support wire 31, j2 to /-)#), the normally closed bimetal switch 9 does not move away from the arc tube 2;
A ceramic Y-coated plate-like current limiting resistor 1 is interposed between the normally closed bimetal switch 9 and the arc tube 2.

The unit structure of the normally closed bimetallic switch 9 and the ceramic-covered plate-like current limiting resistor 1 is shown in FIG. Tsume υ, 11 & Hiro meandering arrangement with resistivity element,
llb is a plate-shaped ceramic body that covers the resistor 11m.

9a is a fixed contact implanted in the ceramic body 11b;
9b is a conductive support wire which is also implanted in the ceramic body 11b and electrically connected to the resistor 21m, 9C is a bimetal piece, and 9d is a movable contact.

In such an embodiment, the radiant heat from the arc tube 2 that dies during lighting is shielded by the ceramic-coated current limiting resistor 11, so the bimetal switch 9 is not overheated, and heating fatigue is prevented. This reduces the rate at which the bimetal piece 9c softens. Therefore, the movable contact 9d reliably contacts and separates from the fixed contact 9a, and Run! The functionality of the bimetal switch 9 will not be lost during the entire life of the bimetal switch 9.
Particularly in the case of 200 watt and 400 watt class rungs, the distance between the arc tube 2 and the bimetal switch 9 is shortened.
The effect becomes remarkable due to the a-thermal action of the above embodiment.

Note that K between the arc tube 2 and the normally closed bimetal switch 9
When the ceramic coated current limiting resistor 11 that also serves as a heat plate is interposed, the radiant heat from the arc tube I is blocked, but convection heat exists in the outer tube 1 and the start-up is delayed. Later, when the lighting tube 2 shifts to stable lighting, the normally closed metal match 9 is heated by the convection heat and opens. The lighting tube 1tlt is protected by not passing any current through the rounded lighting tube 10. In this case, the opening timing of the normally-closed bimetal switch 9 may be slightly delayed compared to the conventional switch shown in FIG. 1, but this delay in opening timing does not pose a major problem in practice.

(Other Embodiments) In the embodiments shown in Figures 3 and 4, the current limiting resistor 11 is formed into a ceramic coated plate shape, and the current limiting resistor 1 also serves as a heat shield, so the number of parts is reduced. Although the inside of the outer tube 1 has a simple configuration, the present invention is not limited to this, and the current limiting resistor II is simply formed of a plate-shaped resistor, which is then coated with mica or the like and formed into a plate shape. The plate-shaped resistor may also serve as a heat shield.

The basic technical idea of the present invention is as shown in FIG.
The intended purpose can be achieved by interposing a heat shield 50 between the two. Note that the heat shield 5o is attached to the support 6 via support wires 51 and 52.

Further, the present invention is not limited to the glow lamp 10 as a starting device, but may be a bimetallic switch.

(Effects of the invention) As detailed below, in the present invention, a heat shield is interposed between the gas tube and the heat-responsive switch, so that the radiant heat from the gas tube during lighting is transferred to the heat shield. This prevents the thermally responsive switch from becoming excessively heated. Therefore, thermal deterioration of the thermally responsive switch is prevented, and there is an advantage that reliable opening/closing operation can be maintained over the entire life of the switch.

[Brief explanation of drawings]

Figures 1 and 2 show a conventional example; Figure 1 is a configuration diagram;
Fig. 2 is a circuit diagram, and Fig. 1m3 and Fig. 4 show an embodiment of the present invention, and Fig. 3 is a configuration diagram. Figure 4 shows a normally closed bimetal switch and a ceramic cover! FIG. 5 is a unit configuration diagram of a plate-shaped current limiting resistor, and FIG. 5 is a configuration diagram showing another embodiment.゛ 1... Outer tube, 2... Arc tube, 3.4... Main electrode, 5... Auxiliary electrode for starting, 9... Normally closed bimetal switch (thermal response switch), IO... Gro1 lighting tube (starting device), 11...ceramic coated plate current limiting resistor,
50... Heat shield. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 L--'' Figure 3m 132 09 514 ＼ '13 +1 Figure 4 1b' 〆Go Figure 5

Claims (3)

[Claims] (1) An arc tube having at least one pair of main electrodes, a starter device for starting the arc tube, and a thermally responsive switch for stopping energization to the starter device after starting the arc tube, in the outer tube. A built-in good metal vapor discharge lamp, characterized in that a heat shield for shielding heat from the arc tube is interposed between the arc tube and the thermally responsive switch. (2) In a device that uses a Glo-1 lighting tube and a current-limiting resistor for lighting tubes as a starting device, the current-limiting resistor is formed into a plate shape, and this plate-shaped current-limiting resistor is connected to the arc tube and the IkE moving switch 7'. The metal vapor discharge lamp according to claim 1, wherein the metal vapor discharge lamp is disposed between the metal vapor discharge lamp and the metal vapor discharge lamp and serves also as a heat transmitting body. (3) The plate-like current limiting resistor has its outer surface covered with a heat-resistant insulator,
The metal vapor discharge lamp according to claim 2, wherein the thermally responsive switch is supported by the heat-resistant insulator.