JP5517107B2 - Amalgam type low-pressure mercury lamp and its lamp lighting power supply - Google Patents

Description

The present invention relates to a low-pressure mercury lamp mainly used for running water sterilization and the like, and a lamp lighting power supply device thereof. In particular, it relates to a low-pressure mercury lamp for sterilization used in water supply and sewerage.

Recently, a method of irradiating ultraviolet rays has been adopted as a sterilization method for water and sewerage, beverage products, food processing water and washing water. In particular, ultraviolet irradiation is widely used in waterworks for the purpose of reducing chlorine and removing cryptosporidium. It has become to. As a typical light source for ultraviolet irradiation, a low-pressure mercury lamp is known. Low-pressure mercury lamps for ultraviolet irradiation usually use quartz glass with excellent ultraviolet transmittance for the arc tube, and a pair of electrodes equipped with tungsten filaments as cathodes at both ends, and this quartz sealed glass The arc tube has a configuration in which a rare gas such as argon and mercury are enclosed. Other than the arc tube material, it is the same as a general fluorescent lamp for illumination including the lighting principle.

Next, the principle and operation of such a low-pressure mercury lamp will be described. As a first step, a preheating voltage is applied to the filaments installed at both ends of the arc tube by a dedicated lighting power supply device called a ballast, and the filament is red hot as a resistance. At this time, the electron emitting substance (hereinafter referred to as an emitter) made of a ternary oxide of BaO, SrO, and CaO applied to the filament reaches 750 ° C. or more, so that thermoelectrons are emitted from the emitter.

As a second step, by applying an alternating electric field between the two electrodes, the emitted thermoelectrons are accelerated, and an elastic collision occurs between the enclosed rare gas and a small amount of mercury vapor, and the mercury atoms are ionized. Then, the plasma state in the arc tube is amplified in an avalanche manner, and discharge is started. This phenomenon is called the Penning effect. In addition, the kinetic energy of the accelerated thermoelectrons collides with the mercury atom, the mercury atom transitions from the ground state to the excited state, and ultraviolet rays having effective wavelengths such as 254 nm and 185 nm which are mercury resonance lines are the wall of the arc tube. And is emitted to the outside of the lamp, and finally the mercury atoms return to the original ground state again. In particular, ultraviolet light in the wavelength range of 200 nm to 280 nm has the effect of erasing the replication function for DNA such as Escherichia coli by irradiation, resulting in bactericidal action. The mercury resonance line, 254 nm, is at the center of the wavelength region where this bactericidal action exists, and is therefore a well-known wavelength called a bactericidal line.

The light of 254 nm wavelength emitted from a general low-pressure mercury lamp is greatly influenced by the mercury vapor pressure, has a peak output at about 0.8 Pa, and the highest luminous efficiency is obtained. At this time, the temperature of mercury located at the coldest part of the arc tube is about 40 ° C. A general lighting fluorescent lamp is designed so that the coldest temperature of the arc tube is 40 ° C. when the temperature is 25 ° C. In addition, ozone cleaning lamps used in flat panel and semiconductor manufacturing processes have been developed to increase lamp current and increase wattage in order to increase the output of ultraviolet rays. Specifically, as a result of combining the lamp emission length with the flat panel size at a lamp current of 4 A or more, the emission length is increased to nearly 2 m, and lamp power exceeding 2 kW has been developed. In such a high-load lamp, the temperature inside the arc tube becomes higher than 40 ° C. Therefore, a part of the lamp arc tube is forcedly cooled by contacting with water-cooled metal, and the temperature of the coldest part Is controlled to 40 ° C.

The configuration of the above-mentioned running water sterilizer is usually a lamp installed in an ultraviolet transmissive quartz tube called a jacket or an outer sleeve, and receives the ultraviolet rays from the lamp by flowing the water to be treated on the outside, thereby effecting sterilization and the like. Is made. Therefore, the lamp installed in the quartz tube is affected by the temperature of the water flowing outside the quartz tube, and the mercury vapor pressure in the lamp fluctuates accordingly, and the ultraviolet irradiation output is determined. The fluctuation range of the temperature of water flowing into clean water and sewage varies greatly depending on the region and seasonal variation. In the case of the target water temperature of general tap water, this temperature range is 10 to 30 ° C. For this reason, the conventional low-pressure mercury lamp has a drawback that the output of 254 nm is 60 to 80% of the peak due to a change in the water temperature in this temperature range, which greatly fluctuates.

Therefore, since mercury vapor pressure fluctuates greatly depending on the external temperature from the standpoint of mercury, adding mercury as an alloy (amalgam) with other metals keeps fluctuations in mercury vapor pressure small. Amalgam-type low-pressure mercury lamps have been developed. As the lighting posture of this type of low-pressure mercury lamp, a horizontal posture is usually adopted. The amalgam in this case is composed of mercury and at least one metal such as bismuth, indium, tin, lead, etc., and is fixed at an appropriate temperature position in the coldest part of the lamp arc tube and during lamp operation. Mercury vapor pressure can be controlled to be constant (see Patent Document 1). In the field of water sterilization, a lamp having a high output and a constant ultraviolet output in the range of the external water temperature of 10 to 30 ° C. is required. Therefore, a low pressure mercury lamp to which this amalgam is added, that is, an amalgam type low pressure mercury lamp is used. It will be mainstream in the future.

JP 2009-266759 A

However, the amalgam type low-pressure mercury lamp has the advantage that the mercury vapor pressure is lower than that of mercury alone due to the alloying of mercury as described above. When the lamp is started when the ambient temperature is low, the temperature of the amalgam in the lamp is similarly lowered, and particularly when the temperature is 10 ° C. or lower, the mercury vapor pressure is remarkably lowered. There was a problem that it was difficult to obtain the effect and it was difficult to start.

The amalgam is composed of mercury and at least one metal such as bismuth, indium, tin, lead, etc., has a granular shape, and is added and fixed in the arc tube during the lamp manufacturing process. Granular amalgam has a viscosity that increases when the mercury weight ratio exceeds 10%, making it difficult to form a granular shape. Therefore, the mercury weight ratio is generally 10% or less. . Therefore, in the case of a lamp to which a grain-shaped amalgam is added, the mercury weight ratio of the amalgam is 10% or less, and there has been a concern about a decrease in starting performance due to a significant decrease in mercury vapor pressure at low temperatures.

The present invention solves the above-mentioned problems, and is amalgam-type low-pressure mercury that is lighted by being mounted in a horizontal position along the quartz tube at the bottom inside the ultraviolet ray-transmissive quartz tube through which water flows outside, and that does not deteriorate the starting performance in a low-temperature environment. An object is to provide a lamp and a lighting power supply device for the lamp.
In order to ensure proper starting performance, the present inventor specifies the mercury weight ratio in the amalgam rather than arranging the amalgam in the coldest part in the arc tube as in the technique described in Patent Document 1. And it came to create this invention paying attention that it is important to arrange | position to the position where the distance of a filament and amalgam exists in an appropriate range.

In order to achieve the above object, the amalgam type low-pressure mercury lamp according to claim 1 of the present invention is mounted and lit in a horizontal posture along the quartz tube at the bottom inside the ultraviolet ray transmissive quartz tube through which water flows. A low-pressure mercury lamp to which an electrode equipped with a filament as a cathode is sealed at both ends of an arc tube made of quartz glass, and a rare gas for starting, and an additive for controlling the mercury vapor pressure together with this. As described above, an amalgam composed of at least one metal such as mercury and bismuth, indium, tin, and lead is enclosed in the arc tube, and a mercury weight ratio A (%) in the amalgam is expressed by the formula (1). The distance B (mm) between the amalgam disposed on the inner surface of the arc tube end portion behind the filament and the filament is in the range represented by the formula (2).
2 ≦ A ≦ 10 (1)
8 ≦ B ≦ 20 (2)

A lamp lighting power supply device according to a second aspect of the present invention is a power supply device that uses the lamp according to the first aspect as a light source. ) Is satisfied.
5 ≦ C ≦ 60 (3)

According to a third aspect of the present invention, there is provided a lamp lighting power supply apparatus according to the present invention, wherein the ratio of the preheating voltage before lighting and during lighting is D, It is characterized by satisfying.
1.2 ≦ D ≦ 2.0 (4)
D = Dp / Dn Dp: preheating voltage before lighting, Dn: preheating voltage during lighting

According to a fourth aspect of the present invention, there is provided a lamp lighting power supply apparatus that uses the lamp according to the first aspect as a light source. ) And when the ratio of the preheating voltage before lighting and during lighting is D, Expression (4) is satisfied.
5 ≦ C ≦ 60 (3)
1.2 ≦ D ≦ 2.0 (4)
D = Dp / Dn Dp: preheating voltage before lighting, Dn: preheating voltage during lighting

The amalgam-type low-pressure mercury lamp of the present invention according to claim 1 is mounted and lit in a horizontal position along the quartz tube at the bottom inside the ultraviolet transmissive quartz tube through which water flows. By setting the weight ratio to 2 to 10% and positioning the amalgam on the arc tube wall within a distance of 8 to 20 mm from the filament, it receives the radiation of the filament preheating, increases the mercury vapor pressure in the lamp, and acts as a penning effect. The starting performance can be improved.

According to a second aspect of the present invention, there is provided a lighting power supply device according to the first aspect of the present invention, in which the mercury in the amalgam is evaporated in the lamp of the first aspect and the lamp can be started within 5 to 60 seconds.

Further, the lighting power supply device of the present invention according to claim 3 has a ratio D (D = Dp / Dn Dp: preheating voltage before lighting, Dn: preheating voltage during lighting) of the preheating voltage before lighting and during lighting. By setting the pressure within the range of 2 to 2.0, the mercury vapor pressure is increased more reliably and quickly, and the lamp starting performance can be improved at low temperatures. Further, it becomes possible to suppress the sputtering of the emitter applied to the filament during this operation.

Moreover, the lighting power supply device of the present invention according to claim 4 which is a combination of claims 2 and 3 can obtain the effect of improving the lamp starting performance at low temperature and suppressing the sputtering of the emitter.

It is the schematic of the sterilizer which mounts the amalgam type low pressure mercury lamp which concerns on the Example of this invention. It is the schematic of the amalgam type low pressure mercury lamp which concerns on the Example of this invention. 1 is a schematic circuit diagram of a lighting power supply device for an amalgam type low-pressure mercury lamp according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Example>
An amalgam type low-pressure mercury lamp according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic front view of a sterilization apparatus equipped with a low-pressure mercury lamp of the present invention in a horizontal posture. 1 is an amalgam type low-pressure mercury lamp (sterilization lamp) according to an embodiment of the present invention, and 2 is a cylindrical water tank ( 3 is a quartz glass sleeve. The sleeve 3 is disposed along the axial direction in the water tank 2, and the lamp 1 is installed in a horizontal posture at the bottom inside the sleeve 3. The water to be treated flowing in the water tank is sterilized by receiving ultraviolet irradiation on the outer periphery of the sleeve 3.

FIG. 2 schematically shows an amalgam type low-pressure mercury lamp according to an embodiment of the present invention. FIG. 2-1 is a plan view and FIG. 2-2 is a front view. 4 is a quartz glass arc tube, 5 is a filament, 6 is an amalgam, 7 is a circumscribed lead wire, and 8 is a ceramic base (base). The arc tube 4 is filled with a rare gas such as argon.

FIG. 3 is a schematic circuit diagram of a lighting power supply apparatus according to an embodiment of the present invention called a ballast for lighting an amalgam type low-pressure mercury lamp, and shows a ballast capable of preheating a filament.

Next, a lighting method of the lamp having such a configuration will be described. In the low-pressure mercury lamp 1, a preheating voltage is applied from the ballast 9 to the filament 5 through the lead wire 7. When the filament current flows, it glows red, and thermionic electrons are emitted from the main emitter containing barium oxide. Further, at the time of lighting, a high voltage exceeding 400 V for starting is applied to the electrodes at both ends from the ballast 9 through the lead wire 7 in the same manner, causing breakdown and discharging, and an alternating lamp current is supplied. The low-pressure mercury lamp of the present invention is lit at a rated power of 240W.

In the conventional low-pressure mercury lamp, the filament preheating time is about 1 second for a fluorescent lamp for general illumination, and about 1 to 3 seconds for other ultraviolet lamps. In general, the operation of starting lighting at the same time when the battery is sufficiently discharged is common.

In the low-pressure mercury lamp 1 according to the embodiment of the present invention, the amalgam 6 is composed of mercury and at least one metal such as bismuth, indium, tin, lead, etc. In this embodiment, the weight ratio A of mercury is 4%. An arc tube having an outer diameter of 15 mm, a total length of 1560 mm, and a distance between electrodes of 1450 mm was used, and a base was fitted into the quartz seal portions at both ends of the arc tube and fixed with an adhesive. The amalgam was placed on the inner surface of the arc tube end behind the filament, and the amalgam was installed at a position where the distance B between the amalgam and the filament was 10 mm.

The mercury weight ratio A in the amalgam is desirably in the range of 2 ≦ A ≦ 10 in order to obtain a desired emission intensity of ultraviolet light in the wavelength range of 200 nm to 280 nm. On the other hand, the appropriate range of the distance B between the filament and the amalgam was confirmed by experiments. If the distance is within the range of 8 ≦ B ≦ 20, the temperature of the amalgam during lighting is from 85 to 120 ° C. which is an appropriate range, and stable UV output And the mercury vapor pressure can be increased by receiving heat radiation from preheating of the filament. Here, the position of the amalgam is not necessarily the position corresponding to the coldest part in the arc tube. When the thickness is less than 8 mm, the amalgam temperature becomes higher than the above level, exceeds the appropriate temperature, and the output of ultraviolet rays is reduced. On the other hand, if it exceeds 20 mm, the effect of heat radiation from the preheated filament to the amalgam is reduced, and it takes time until the temperature of the amalgam falls and the mercury vapor pressure necessary for starting the lamp is obtained. As a design above, setting over 20 mm is difficult.

Next, the relationship between the water temperature and the preheating time and the lamp startability was investigated for the lamp having the above configuration. Table 1 shows the results of the lamp start test. In this case, the water temperature was 3, 5, 10, 15, and 20 ° C. From Table 1, when the preheating time C is 4 seconds or less, there is a probability that the lamp will not start, but when it is 5 seconds or more, the water temperature is 3 ° C. or more and the probability of starting is 100%. The upper limit of the preheating time is not preferably over 60 seconds in consideration of practical aspects. Therefore, it is desirable that the preheating time C is 5 seconds or more and 60 seconds or less.

In addition, using a ballast (lighting power supply device) that can switch between the preheating voltage of the filament and the lighting voltage, the filament preheating voltage ratio D, preheating time, and lamp start before lighting and lighting under the condition of a water temperature of 3 ° C. The relationship with sex was investigated. The results are shown in Table 2. As shown in Table 2, it was confirmed that the preheating time can be shortened to 3 seconds. However, when D exceeds twice, blackening of the electrode is recognized and the filament temperature becomes high for a long time, so that the emitter is scattered and the lamp life may be shortened. Thus, it was confirmed that the filament preheating voltage ratio D is preferably in the range of 1.2 to 2.0.

As explained above, according to the present invention, it is possible to add an apparatus for heating amalgam from the outside to an amalgam type low-pressure mercury lamp to which an amalgam having a mercury weight ratio of 10% or less is added. With a simple configuration of a lamp and ballast (lighting power supply), it is possible to significantly improve the starting performance at low temperatures by adjusting the amalgam position, preheating time, and preheating voltage within the specified range. Become.

In addition, when the technology of the present invention is used, it is possible to expand the application to UV-applied products using an amalgam type low-pressure mercury lamp that can be used not only in sterilization but also in cold regions.

The present invention is mainly used in running water sterilizers using ultraviolet lamps, ultraviolet oxidation apparatuses, and the like.

DESCRIPTION OF SYMBOLS 1 ... Lamp 2 ... Water tank 3 ... Quartz glass sleeve 4 ... Quartz glass arc tube 5 ... Filament 6 ... Amalgam 7 ... Lead wire 8 ... Ceramic base 9 ···stabilizer

Claims (4)

A low-pressure mercury lamp that is mounted and lit in a horizontal position along the quartz tube at the inner bottom of an ultraviolet ray transmissive quartz tube through which water flows outside, with filaments serving as cathodes at both ends of the arc tube made of quartz glass The equipped electrode is sealed, and is composed of a rare gas for starting, and at the same time, mercury and at least one metal such as bismuth, indium, tin and lead as an additive for controlling the mercury vapor pressure. The amalgam is enclosed in the arc tube, the mercury weight ratio A (%) in the amalgam is in the range represented by the formula (1), and the amalgam and the filament are arranged on the inner surface of the end of the arc tube behind the filament The amalgam type low-pressure mercury lamp is characterized in that the distance B (mm) is in the range represented by the formula (2).
2 ≦ A ≦ 10 (1)
8 ≦ B ≦ 20 (2) The lamp power supply device for lighting a lamp according to claim 1, wherein the filament preheating time C (seconds) from the time of turning on the power to the lamp lighting satisfies the formula (3).
5 ≦ C ≦ 60 (3) The lamp power supply device for lighting a lamp according to claim 1, wherein the ratio of the preheating voltage before lighting and the preheating voltage during lighting is D, and the formula (4) is satisfied.
1.2 ≦ D ≦ 2.0 (4)
D = Dp / Dn Dp: preheating voltage before lighting, Dn: preheating voltage during lighting In the lighting power supply device for lighting the lamp according to claim 1, the filament preheating time C (second) from the time of turning on the power to the lamp lighting satisfies the formula (3), and the ratio of the preheating voltage before lighting and during lighting. A lamp lighting power supply device satisfying the expression (4) where D is D.
5 ≦ C ≦ 60 (3)
1.2 ≦ D ≦ 2.0 (4)
D = Dp / Dn Dp: preheating voltage before lighting, Dn: preheating voltage during lighting

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