JPH07105911A - Low-pressure mercury vapor discharge lamp, lighting method of the discharge lamp, lighting circuit, and ultraviolet irradiation device using the discharge lamp - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent blackening due to mercury oxide and to prevent the reduction of UV maintenance rate. In a low-pressure mercury vapor discharge lamp in which electrodes 12 are sealed at both ends of an arc tube 11 and mercury and a rare gas are sealed in the arc tube 11, an oxygen absorbing material is provided on at least a part of the inner surface of the arc tube 11. 14 is attached.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the purification of various liquids and gases,
Or low pressure mercury vapor discharge lamp used for decomposition of organic matter,
The present invention relates to a lighting method of a discharge lamp, a lighting circuit, and an ultraviolet irradiation device using the discharge lamp.

[0002]

2. Description of the Related Art An ultraviolet lamp as a low-pressure mercury vapor discharge lamp is constructed by sealing a pair of electrodes at both ends of a bulb (light emitting tube) and enclosing mercury and a rare gas in the bulb. The lighting principle is the same as that of a known fluorescent lamp. On the other hand, what is different from the fluorescent lamp of the ultraviolet lamp is that the phosphor coating is not used and that the glass tube forming the bulb is made of quartz glass having an excellent far ultraviolet transmittance.

Since such an ultraviolet lamp emits deep ultraviolet rays by the emission of mercury vapor, it is used in a wide range of fields such as sterilization of water in a water purification plant for sewage and sewage, or production, processing and treatment of products.

By the way, in the conventional ultraviolet lamp, the lamp current is 0.5 A or less, the input per electrode distance 1 cm is 1 W or less, and the input per lamp is 100 at most.
It was W or less.

In recent years, there has been an increasing demand for a strong ultraviolet light source capable of decomposing organic substances and improving the sterilizing power of water, and in order to meet the demand, a lamp having a high lamp current and a high output has been developed. There is. As a result, it is now possible to realize an ultraviolet lamp with a lamp current of 5 to 10 A and an input distance between unit electrodes of 5 W / cm or more.

[0006]

However, on the other hand, although the high output can be achieved as described above, there is a new problem that the ultraviolet ray maintenance rate is lowered as the lamp current is increased.
That is, the lamp is blackened in a lighting time of several hundred hours, ultraviolet rays are not transmitted through the blackened lamp, and particularly when the lamp current is 1.0 A or more, the blackening generation rate is increased.

In order to solve this, the present inventor investigated the cause of blackening of the lamp. First, the black matter was analyzed and found to be mercury oxide, which is a compound of mercury and oxygen. In this case, mercury is the enclosure of the lamp, but oxygen is not the intentional enclosure.

Next, the reason why oxygen was produced was investigated.
The reason for the presence of oxygen in the lamp is presumed to be that it was generated from either the glass (SiO ₂ ) or the emitter (BaO) that is the bulb material. When the generation rate of black oxide was examined, it was found to be correlated with the lamp current.

That is, as the lamp current increases,
The rate of black matter formation is increasing. Therefore, the present inventor considered that the reason for generating oxygen was decomposition of the emitter. But,
If electrons are emitted from the emitter, it is unavoidable that BaO decomposes and emits. At the present time, the emitter applicable to the low-pressure mercury lamp and capable of emitting a large current is B
Only aO exists.

Therefore, as a result of various studies on the means for adsorbing oxygen from the emitter, the inventor has found that Zr, Al and the like are available as getter substances for adsorbing oxygen. However, when such a getter was provided around the electrode, in the discharge space, and on a part of the wall of the electrode tube, the effect was confirmed, and it was found that the oxygen adsorbing substance (getter) was arranged only on a specific part. , It turned out that the effect was not so great.

It is considered that the reason is that oxygen generated from the emitter immediately moves to the discharge space having a low partial pressure, is combined with mercury in the plasma, and adheres to the tube wall as mercury oxide. The mercury oxide once attached does not evaporate again, so that oxygen is not adsorbed by the getter.

Therefore, the present inventor has devised means for widely distributing getters on the tube wall and adsorbing oxygen alone or oxygen in mercury oxide on the tube wall. The getter powder was mixed with nitrocellulose or butyl acetate and applied to the inner wall of the tube and dried. However, it is impossible to form a getter film even by taking such a means.

The present invention has been made in consideration of the above-mentioned circumstances, and it is a low-pressure mercury vapor discharge lamp that prevents blackening due to mercury oxide and has a high UV maintenance rate, a method for lighting the discharge lamp, a lighting circuit, and the lighting circuit. An object is to provide an ultraviolet irradiation device using an electric lamp.

[0014]

In order to solve the above-mentioned problems, the low-pressure mercury vapor discharge lamp according to claim 1 of the present invention has electrodes sealed at both ends of the arc tube and the inside of the arc tube. In a low-pressure mercury vapor discharge lamp in which mercury and a rare gas are enclosed, at least a part of the inner surface of the arc tube is coated with an oxygen absorbing material.

A low-pressure mercury vapor discharge lamp according to a second aspect of the invention is characterized in that the oxygen absorbing material according to the first aspect is applied to almost the entire inner surface of the arc tube.

Further, in the low pressure mercury vapor discharge lamp according to claim 3, the oxygen absorbing material according to claim 1 or 2 is Zr,
It is characterized by comprising at least one of Al.

According to a fourth aspect of the present invention, there is provided a method for lighting a low-pressure mercury vapor discharge lamp, wherein a low-pressure mercury vapor discharge lamp having an oxygen absorbing material coated on at least a part of an inner surface of the arc tube is lit with a lamp current of 1.0 A or more. It is characterized by

A lighting circuit for a low-pressure mercury vapor discharge lamp according to a fifth aspect of the present invention comprises an AC power supply and an inverter section for converting the AC power supply into a rectangular wave or a high frequency, and at least part of the inner surface of the arc tube absorbs oxygen. It is characterized in that a low-pressure mercury vapor discharge lamp coated with a material is turned on.

According to a sixth aspect of the present invention, there is provided an ultraviolet irradiation device in which a low pressure mercury vapor discharge lamp according to any one of the first, second and third aspects is housed in a housing.

[0020]

In the low-pressure mercury vapor discharge lamp according to the present invention having the above structure, the oxygen absorbing material is deposited on at least a part of the inner surface of the arc tube so that the oxygen absorbing material is generated in the arc tube. Adsorbs oxygen. As a result, it is possible to prevent blackening of the discharge lamp and maintain a high ultraviolet ray maintenance rate. In this case, it is preferable to apply the oxygen absorbing material to almost the entire inner surface of the arc tube. The oxygen absorber is Zr,
It is preferable to use a material selected from at least one of Al.

Further, in the method of lighting a low-pressure mercury vapor discharge lamp, a high output can be achieved by lighting with a lamp current of 1.0 A or more.

Further, the lighting circuit of the low-pressure mercury vapor discharge lamp complicates the circuit configuration by lighting the low-pressure mercury vapor discharge lamp with an AC power source and an inverter section for converting this AC power source into a rectangular wave or a high frequency. There is nothing to do.

When the low-pressure mercury vapor discharge lamp according to the present invention is applied to an ultraviolet irradiation device, a high ultraviolet maintenance rate can be maintained for a long period of time, so that the service life can be extended and the reliability can be improved.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an ultraviolet irradiation device to which an embodiment of a low pressure mercury vapor discharge lamp according to the present invention is applied. In FIG. 1, the ultraviolet irradiation device is electrically connected to an AC power supply 1 and includes an ultraviolet lamp 10 as a low-pressure mercury vapor discharge lamp housed in a housing 2 and an inverter unit 20 for converting the AC power supply 1 into a high frequency. I have it.

In the ultraviolet lamp 10, a pair of electrodes 12 and 12 are sealed by stems 13 and 13 at both ends of a quartz glass bulb (light emitting tube) 11 which is bent in a U-shape. It is configured by enclosing mercury and a rare gas therein. The valve 11 is uniformly coated with an oxygen absorbing material 14 made of Zr or Al on the entire inner surface except the stem 13.

As shown in FIG. 2, each electrode 12 is composed of an anode 15 and a filament 16, and is cooled by a heat pipe 17 attached to the stem 13.
The heat pipe 17 has a radiation fin 17a, and a fan 18 is installed in the vicinity of the radiation fin 17a. By rotating the fan 18, the radiation fin 17a is cooled and radiates heat. The anode 15 and the filament 16 are each provided with a lead wire.

The inverter section 20 has a transformer section 21 and an inverter circuit 22, and the transformer section 21 is provided with a main winding 23, diodes 24 and 24 for preventing backflow, and filament preheating windings 25 and 25. ing.

Next, the operation of this embodiment will be described.

A method of uniformly depositing the oxygen absorbing material 14 made of Zr or Al on the entire inner surface of the valve 11 excluding the stem 13 will be described. That is, Zr or Al powder is replaced with Al ₂ O ₃ , MgO, TiO ₂ , Si.
If mixed with oxides such as O ₂ , ScO ₃ , M ₂ O ₃ (M is a rare earth element), mixed with nitrocellulose or butyl acetate to make a solvent, and coated on the inner surface of the valve 11 and dried, a wide range of oxygen adsorbing substances can be obtained. (Getter) can be distributed.

By the way, if Zr or Al is left as it is, it is immediately oxidized even at room temperature, and the effect as a getter is lost. Further, it is very difficult to reduce Zr and Al that have been once oxidized. Therefore, the powder of Zr and Al is wrapped with a film that does not decompose at 800 ° C. or lower and does not allow oxygen to pass through, and this powder is dissolved in a solvent, for example, a mixed liquid of nitrocellulose and the above oxide, and applied on the inner surface of the valve 11. To do.

Then, baking is performed in the atmosphere at about 500 ° C. to decompose and remove the nitrocellulose. Then, after sealing the electrode 12 and the like in the valve 11, the gas is exhausted.
During this evacuation process, the inside of the valve 11 is evacuated to 800-9
Heat at 00 ° C. In this process, the film encapsulating Zr and Al is disassembled and removed, and Zr is formed on the inner surface of the valve 11.
Alternatively, Al is deposited.

The ultraviolet lamp thus manufactured was lit at a lamp current of 1.0 A or more and the life was evaluated. As a result, it was confirmed that mercury oxide was hardly generated even after lit for 8500 hours or more. This is because Zr or Al as an oxygen absorbing material adsorbs oxygen of mercury oxide generated in the bulb 11. As described above, according to the present embodiment, it is possible to prevent the bulb 11 from blackening and prevent the deterioration of the ultraviolet ray maintenance rate even when the lamp current is turned on at 1.0 A or more.

In the lighting method of this embodiment,
Higher output can be achieved by lighting with a lamp current of 1.0 A or more.

Further, the lighting circuit of this embodiment can simplify the circuit structure by lighting the bulb 11 by the AC power supply 1 and the inverter section 20 for converting the AC power supply 1 into a high frequency.

When the low-pressure mercury vapor discharge lamp of this embodiment is applied to an ultraviolet irradiation device, a high ultraviolet maintenance rate can be maintained for a long period of time, so that the life can be extended and the reliability can be improved.

In the above embodiment, the oxygen absorber 14 made of Zr or Al is uniformly applied to the entire inner surface of the valve 11 excluding the stem 13 portion. However, the present invention is not limited to this, and at least a part of the inner surface of the valve 11 is not limited to this. The oxygen absorber 14 may be applied to the above.

[0038]

As described above, according to the low-pressure mercury vapor discharge lamp of the present invention, the oxygen absorbing material is deposited on at least a part of the inner surface of the arc tube, so that the oxygen absorbing material is kept inside the arc tube. Since the generated mercury oxide is adsorbed with oxygen, it is possible to prevent blackening of the discharge lamp and maintain a high UV maintenance rate.

According to the lighting method of the low-pressure mercury vapor discharge lamp, a high output can be achieved by lighting with a lamp current of 1.0 A or more.

Furthermore, the lighting circuit of the low-pressure mercury vapor discharge lamp complicates the circuit structure by lighting the low-pressure mercury vapor discharge lamp with an AC power source and an inverter section for converting this AC power source into a rectangular wave or a high frequency. There is nothing to do.

Further, according to the ultraviolet irradiation device using the low-pressure mercury vapor discharge lamp according to the present invention, since a high ultraviolet maintenance rate can be maintained for a long period of time, the life can be extended and the reliability can be improved. .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an ultraviolet irradiation device to which an embodiment of a low-pressure mercury vapor discharge lamp according to the present invention is applied.

FIG. 2 is an enlarged view showing an electrode portion of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 Housing 10 Ultraviolet lamp (low-pressure mercury vapor discharge lamp) 11 Bulb (light emitting tube) 12 Electrode 13 Stem 14 Oxygen absorbing material 15 Anode 16 Filament 17 Heat pipe 18 Fan 20 Inverter section 21 Transformer section 22 Inverter circuit

Claims (6)

[Claims] 1. A low pressure mercury vapor discharge lamp in which electrodes are sealed at both ends of an arc tube and mercury and a rare gas are sealed in the arc tube, and an oxygen absorbing material is provided on at least a part of an inner surface of the arc tube. A low-pressure mercury vapor discharge lamp characterized by being deposited. 2. The low-pressure mercury vapor discharge lamp according to claim 1, wherein the oxygen absorbing material is deposited on substantially the entire inner surface of the arc tube. 3. The low-pressure mercury vapor discharge lamp according to claim 1, wherein the oxygen absorbing material is made of at least one of Zr and Al. 4. A low-pressure mercury vapor discharge lamp characterized in that a low-pressure mercury vapor discharge lamp in which at least a part of the inner surface of an arc tube is uniformly coated with an oxygen absorbing material is lit with a lamp current of 1.0 A or more. Lighting method. 5. A low-pressure mercury vapor discharge lamp in which at least a part of the inner surface of an arc tube is coated with an oxygen absorbing material by an AC power supply and an inverter unit that converts this AC power supply into a rectangular wave or a high frequency. Lighting circuit for low-pressure mercury vapor discharge lamp characterized by. 6. An ultraviolet irradiation device, characterized in that a low-pressure mercury vapor discharge lamp according to claim 1 is housed in a housing.