JPS6079664A - Low pressure mercury lamp - Google Patents

Abstract

PURPOSE:To obtain a low pressure mercury lamp of the medium or high output type by fusing electrodes used as cold cathodes and auxiliary anodes adjacent to the electrodes at the ends of the emission tube and charging the emission tube with a proper amount of mercury and an inactive gas at an inactive gas partial pressure of a specified level or below. CONSTITUTION:Electrodes 2a and 2b used as cold cathodes and auxiliary anodes 3a and 3b adjacent to the electrodes 2a and 2b are fused to the ends of an emission tube 1 made of a substance such as ultraviolet-ray-transmitting quartz glass. After that, the emission tube 1 is charged with a proper amount of mercury and an inactive gas at an inactive gas partial pressure of 5torr or below, thereby constituting a low pressure mercury lamp which is ignited with an input of 2- 8W per 1cm interelectrode distance. As a result, the output of ultraviolet rays is increased by charging the inactive gas at a decreased pressure. Furthermore, it is possible to realize a medium output and a high output by installing the auxiliary anodes 3a and 3b to reduce the temperature of the cold cathodes thereby causing a decreased amount of electron-discharging matter to be scattered from the electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in low-pressure water needles used for surface sterilization of foods and their packaging, sterilization of raw water for drugs and cosmetics, and the like.

Conventionally, a hot cathode has generally been used in low-pressure mercury lamps used for various sterilization purposes.

On the other hand, recently, there has been a growing demand for low-pressure mercury lamps with increased output, and medium-to-high-output low-pressure mercury lamps with an interelectrode distance of 1 and an input of 2 to 8 W have been developed and put into use.

However, when a hot cathode is used as an electrode in such a discharge lamp, problems arise in that the lamp input and lamp current are large, resulting in burnout of the electrodes and scattering of electron-emitting substances, which significantly shortens the life of the discharge lamp.

Therefore, in the medium- and high-output low-pressure mercury lamps mentioned above,
Up until now, the hot cathode was water-cooled to prevent burnout, and the pressure of inert gas inside the tube was increased to prevent electron-emitting material from scattering.

However, if the hot cathode part is water-cooled, the structure becomes complex? (Large size and cost in Ii) There is a drawback that it becomes A. There is also a drawback that increasing the inert gas filling pressure in the cylinder lowers the ultraviolet output and lowers the starting performance.

The present invention was made in view of the above points, and it is an object of the present invention to provide a medium-to-high output low-pressure mercury lamp that has a simple structure, is compact, economical, has a large P1 ultraviolet output, and has good starting performance. It is something to do.

FIG. 1 shows an external view of a low-pressure mercury lamp according to the present invention. In the figure, reference numeral 1 denotes an arc tube made of a heat-resistant and ultraviolet-transparent material such as quartz glass. Electrodes 2a and 2b are sealed at both ends of the arc tube 10, and an inert gas such as arcon gas is sealed inside the tube along with excess mercury. The input for the distance 16n between electrodes 2a and 2b is 2~
It is set to about 8w. Such a lamp input can be realized by, for example, directly cooling the arc tube 1 with water. However, with input like this,
The lamp current is approximately 1 to IOA, which is significantly larger than that of conventional discharge lamps. For this reason, it is no longer possible to use the entire thermal lB pole as an electrode.

Therefore, this method uses a cold cathode, such as that used in coracoidal discharge lamps, as the electrode. Furthermore, in order to further increase the UV output, the inert gas pressure inside the tube was increased to 5 torr.
Select r or less. Figure 2 shows the relationship between the inert gas filling pressure and the ultraviolet output.
The inert gas pressure was about 5 torr as described above.
It is clear that the output of ultraviolet rays can be increased by doing the following. However, when the inert gas pressure is lowered,
The scattering of the electron emitting material applied to the electrodes also becomes significant. This tendency is especially seen when the electrode temperature rises. Therefore, in the present invention, 1 auxiliary 1 mirror 4 is located close to the cold cathodes 2a and 2b.
;(・3a and 3b are provided to lower the temperature of the cold cathode.

As a result, the low-pressure mercury phantom according to the present invention can achieve a medium-to-leakage power ratio with the above-mentioned input, and -
It is possible to obtain a round ultraviolet output 'f with no polar burnout.

FIG. 3 shows the variation characteristics of the ultraviolet output of the low-pressure mercury lamp according to the invention and the conventional low-use water lamp.

In the figure, A shows the percentage of the low-pressure water pump according to the present invention, B shows the percentage using a cold cathode as the electrode, and C shows the percentage using the hot cathode as the electrode.

[Brief explanation of drawings]

Figure 1 is a side view of the low-pressure water button phantom according to the invention, Figure 2 is a cross-sectional diagram of inert gas personal pressure and ultraviolet output in a low-pressure mercury lamp, and Figure 3 is a side view of the low-pressure mercury phantom according to the invention and the conventional one. It is a comparison diagram of the lighting time of a low-pressure mercury lamp and the glaze quality of the ultraviolet light output. Procedural correction layer (5 pieces) 1986 2nd Patent Chief Kazuo Wakasugi 1. 41 Displays 1988 Keiku Sekoku No. 186354 2, Name of Hikari Low Pressure Water Iron Sword 3 Relationship with the person making the amendment Patent issue & i + residence H [〒105 No. 4, Shiba 3-chome, Minato-ku, Tokyo, January 11, 1982 (Shipping date = January 31, 1982) 5
, Details subject to formalities No. 6 Purification of details 1 to be amended (no change in content)

Claims (1)

[Claims] Cathodes (2a) and (2b) are placed at both ends of the arc tube (1), respectively.
and the auxiliary anodes (3a) and (3b) adjacent thereto are sealed, and the electrodes are inserted into the interior of the arc tube (1) together with an appropriate amount of mercury into an inert gas at a pressure of 5 torr or less. A low-pressure mercury phantom that uses a pipe to catch fish with an input of 92 to 8 W per meter distance.