JPH073782B2 - High output sterilization lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a high-power sterilization lamp used for purification of various gases and liquids and various other sterilization.

(Prior Art) A sterilizing lamp is constructed by incorporating a pair of electrodes at both ends of a bulb and enclosing a rare gas and mercury in the bulb, and its lighting principle is exactly the same as that of a known fluorescent lamp. The difference from the fluorescent lamp is that no fluorescent substance coating is used and that glass or quartz glass having excellent far-ultraviolet transmittance is used as the glass tube constituting the bulb. Such a germicidal lamp emits far-ultraviolet rays of 254 nm, that is, germicidal rays due to the emission of mercury vapor, so that it can be used for sterilizing water in sewage purification plants.
It is also used in a wide range of fields such as sterilization of various gases or production, processing, and treatment of products.

However, the conventional sterilizing lamp has an input per cm distance between electrodes of 1 W (watt) or less, and the total input per lamp is about 100 W, which is a relatively low output.

Naturally, low-power sterilization lamps also have low sterilization ability, so if they are to be used in large equipment such as water purification facilities, many lamps must be used and many accessories are required.

For these reasons, the development of a high-power germicidal lamp has recently been requested.

As a high-power sterilization lamp, the one described in JP-A-56-160755 is known. In this publication, an arc tube made of ozone-less quartz glass with an inner diameter of 10 mm is used. Inside the arc tube, two sets of electrodes, one set for the cathode and one set for the anode, are installed at both ends. Rare gas and mercury are filled in the lamp, and the lamp current is 4A at an arc length of 300mm.
(Ampere), a lamp with a power consumption of about 200 W is described.

Further, the publication also states that "a small-sized, long-life low-pressure mercury lamp device that can be used at a current value of several + A can be easily obtained." The above specific description is not made.

(Problems to be Solved by the Invention) According to the experiments conducted by the present inventors, increasing the lamp current allows more electric input to the lamp, resulting in higher emission intensity of far-ultraviolet rays. On the other hand, it was found that the relative radiation efficiency decreased and this tendency became remarkable especially at 5 A or higher.

The present invention solves the above-mentioned drawbacks, and an object of the present invention is to provide a high-power sterilizing lamp capable of preventing a significant decrease in relative radiation efficiency even when the lamp current is increased to increase the radiation output of far-ultraviolet rays. To do.

[Structure of Invention]

(Means for Solving the Problems) In the present invention, the inner diameter of an arc tube having electrodes provided opposite to each other and having a rare gas and mercury vapor supply source enclosed therein is D, and the lamp current is I (A). At this time, it is configured to satisfy D ≦ 40 mm D−I ≧ 10 5 A ≦ I ≦ 30 A.

[Action]

According to such a configuration, the electric current input to the lamp can be increased due to the increase in the lamp current, the output of far ultraviolet rays can be increased accordingly, and the inner diameter D of the arc tube is increased. By regulating the relationship with the magnitude of the lamp current, it is possible to prevent a significant decrease in the relative emission efficiency of far-ultraviolet rays due to the mercury vapor pressure (tube wall temperature) becoming too high due to an increase in the lamp current. .

(Embodiment of the Invention) The present invention will be described below based on an embodiment shown in the drawings.

In FIG. 1, (1) is an arc tube made of ozone-less quartz, having an inner diameter of D25 mm and a tube length of 2300 mm. Both ends of the arc tube (1) are sealed with stems (2) and (2) made of hard glass or the like, and electrodes are supported by these stems (2) and (2). An intermediate glass (not shown) having a coefficient of thermal expansion between those of the ozoneless quartz of the arc tube (1) and the hard glass of the stems (2) and (2) is interposed. Is desirable.

The cathode (3) and the anode (4) are installed as one set at each end of the arc tube (1), and two sets are provided at both ends.

The cathode (3) is composed of a coil filament and both ends thereof are connected to the internal lead wires (5) and (6), respectively. The filament cathode (3) is composed of, for example, a triple coil so as to withstand a large current, and an oxide (not shown) made of at least one of barium, calcium and strontium is applied as an electron emitting substance.

The anode (4) is made of a coil or a solid material, is arranged so as to project toward the discharge space side from the filament cathode (3), and is connected to another internal lead-in wire (7).

The distance between the pair of anodes (4) facing each other, that is, the distance between the electrodes, is set to 2000 mm.

Each of the internal introduction lines (5), (6) and (7) is hermetically penetrated through the stem (2) and guided to the outside.

The internal lead-in wires (5), (6) connected to the filament cathodes (3) of the pair facing each other are connected to the secondary windings (9), (9) of the transformer (8) outside the lamp. The other internal lead-in wires (7) connected to the respective anodes (4) of the pair facing each other are connected to the other two of the transformers (8) via the ballast (10) outside the lamp.
It is connected to the next winding (11).

Further, the internal lead-in wires (6) and (7) are connected to each other outside the lamp, so that the lamp current is also applied to the cathode (3).

The primary winding (12) of the transformer (8) is connected to a commercial power source, for example, a 100V or 200V AC power source.

In the arc tube (1), 1 Torr of argon gas was filled as a rare gas for starting, and the mercury vapor supply source (1
5) is housed.

As shown in FIG. 2, the mercury vapor supply source (15) is configured by accommodating an amalgas (17) in a metal capsule (16).

In the present example, as the amalgam (17), Bi-In-Hg (Hg
4% by weight, 240 mg was used, and metal capsules (1
In 6), a nickel (Ni) pipe with an inner diameter of 3 mm is used with both ends closed.

The metal capsule (16) is provided with a small hole (18) of a size that prevents the amalgam (17) from flowing out even when it is in a molten state, and also has a fixing leg (19). Is provided.

Such a metal capsule (16) includes the fixing leg (1
9) is housed in the arc tube (1) by being joined to any of the internal lead-in wires (5), (6) or (7). In this case, the amalgam (17) housed in the metal capsule (16). )
However, the inner temperature of the end of the arc tube (1) is 100 to 100 ° C. so that it is closer to the end of the arc tube (1) than the cathode (3) and the anode (4). It is installed in a position that is an area of about 130 ° C.

In addition, (20) is a molybdenum foil in which indium is plated, and the indium on the surface forms a part alloy with mercury during lighting and plays a role of limiting the mercury vapor pressure.

Also, (21) is a getter for adsorbing hydrogen, which is often used in discharge lamps.

In the lamp with the above configuration, the primary winding (1
2) is connected to a commercial power source, such as a 100V or 200V AC power source, and a potential difference is generated between both ends of the secondary winding (11) of this transformer (8), and this potential difference is applied between the electrodes to turn on the lamp. Let When the lamp current I is turned on at 7 A, a lamp power of 1000 W is obtained in the natural cooling state.

A lamp having such a structure has a lamp current I of 7 A when it is turned on.
However, since the inner diameter D of the arc tube is increased to 25 mm, it is possible to sufficiently alleviate the decrease in the relative radiation efficiency of far ultraviolet rays.

Furthermore, when the lamp current is increased, both the current density and the lamp power density per unit length significantly increase as compared with the conventional low-power sterilization lamp, so that the wall temperature of the arc tube during lighting is 150%. The temperature reaches up to 300 ° C, and the temperature of the tube wall becomes uneven, which causes non-uniform distribution of the density of mercury vapor in the arc tube, which easily causes uneven light emission in the longitudinal direction of the lamp. Especially, this phenomenon is more likely to occur in a long lamp having an arc length of, for example, more than 1000 mm and a large output lamp having a large input density (W / cm). One of the countermeasures is to reduce the pressure of the rare gas enclosed in the arc tube. If the pressure of the rare gas is too low, the voltage required for lighting will be too high, and the electrode constituent materials will be scattered during lighting. This results in a short life. However, if the inner diameter D of the arc tube is made larger than that of the conventional lamp as in the lamps of the above-described embodiments, it becomes possible to prevent uneven light emission without lowering the rare gas pressure so much.

FIG. 3 compares the conventional lamp (D = 10 mm) and the lamp of this embodiment with D = 25 mm, and compares how the relative radiation efficiency of far ultraviolet rays decreases as the lamp current I increases. Is shown. The relative radiation efficiency of the far-ultraviolet light is a value obtained by dividing the far-ultraviolet light output reading near 254 nm by the discharge input (W), and a sensor of 254 nm output of the measuring instrument manufactured by Tokyo Optical Co., Ltd. UV intensity meter "UV
R-254 ”was used.

The values of the curves in the figure are the typical values of the lamp current at which the relative radiation efficiency at 254 nm becomes maximum when various factors such as mercury vapor pressure and rare gas pressure are changed.

As can be seen from the figure, the absolute far ultraviolet relative radiative efficiency of the lamp of this embodiment is extremely high as compared with the conventional lamp even when the lamp current is increased.

Here, in general, it is necessary to increase the lamp current in order to set the same lamp power when the inner diameter of the arc tube is increased without changing the arc length.

Therefore, the lamp of this embodiment requires about twice the lamp current as compared with the conventional one to obtain the same lamp power, but the lamp of this embodiment can be lit at a high current. , Sufficient relative radiation efficiency is obtained.

By the way, the lamp current of the conventional lamp is 5A, and 10A in this embodiment.
Comparing each of the above cases, the relative radiation efficiency of the conventional one is about 7, while that of the present embodiment is
It will be about 11.

Next, with the inner diameter D of the arc tube in the range of 10 to 50 mm and the lamp current I in the range of 5 to 35 A, the results of examining the relationship between the relative radiation efficiency and the uneven light emission of various lamps in which D and I are combined are shown. Shown in the table below. In the table, the relative radiation efficiency is indicated by ◯, which is satisfactory at 7.5 or higher at the level shown in FIG. 3, Δ is not so bad that it is 6 to less than 7.5 but not satisfactory, and × is unsatisfactory.
Is satisfactory, Δ is somewhat unsatisfactory, and × is unsatisfactory. Further, in the comprehensive judgment, the relative radiation efficiency and the emission unevenness are both ○, and the others are ×.

From the table, it can be seen that if (D−I) ≧ 10, satisfactory results can be obtained for both the relative radiation efficiency and the emission unevenness. However, when I is 30 A or more, uneven light emission due to non-uniformity of mercury vapor density occurs, and when D is 45 mm or more, the mercury vapor layer in the atomic state becomes thicker, which is so-called self-absorption that absorbs deep ultraviolet rays. Is caused, and the relative radiation efficiency decreases, which is not possible.

Therefore, when the above results are summed up, it is understood that it is sufficient to satisfy 5A ≦ I ≦ 30A D−I ≧ 10 D ≦ 40 mm.

In the above embodiment, the cathode and the anode were installed as one set at each end of the arc tube, and a total of two sets were provided at both ends.
It may be of a type in which a pair of electrodes are simply provided in pairs, and the shape of the arc tube is not limited to a straight tube, but may be a bent shape such as a U-shaped tube. Further, the mercury vapor supply source is not limited to the amalgam but may be a mercury single substance enclosed.

〔The invention's effect〕

As described above, according to the configuration of the present invention, even if the lamp current is increased to increase the radiation output of far-ultraviolet rays (sterilization rays), a large decrease in relative radiation efficiency and a large output that can prevent uneven emission can be prevented. A germicidal lamp can be provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a high-power sterilization lamp and a lighting device according to the present invention, FIG. 2 is a configuration diagram of a mercury vapor supply source enclosed in the lamp, and FIG. 3 is a relative lamp current and far ultraviolet rays. 5 is a graph showing the relationship with the radiation efficiency as a result of a comparative test between a conventional arc tube having a small inner diameter and a thick tube of the present invention. (1) …… Arc tube, (3) …… Cathode, (4) …… Anode,
(15) …… Mercury vapor supply source, (D) …… Arc tube inner diameter.

Claims (1)

[Claims] 1. An inner diameter of an arc tube in which electrodes are provided opposite to each other and a rare gas and mercury vapor supply source is enclosed inside is D (mm),
A high-power germicidal lamp characterized by satisfying the following conditions: D ≦ 40 mm D−I ≧ 10 5 A ≦ I ≦ 30 A, where I (A) is the lamp current.