JPS6079663A - High output low pressure mercury lamp - Google Patents

Abstract

PURPOSE:To obtain a high output of ultraviolet rays stably by directly cooling with water a low pressure mercury lamp which radiates ultraviolet rays and is installed in a water cooling jacket and maintaining the temperature of the cooling water at a specific level. CONSTITUTION:A low-pressure mercury lamp 1 which radiates ultraviolet rays having an input of 2-8W per 1cm interelectrode distance is installed in a water- cooled jacket 2. The mercury lamp 1 is installed in a water cooling jacket 2 and the surface of the emission tube of the mercury lamp 1 is directly cooled with water. The average temperature of the cooling water is maintained within the range of 30-50 deg.C by either cooling a cooling water tank 3 by means of tap water or well water or circulating the cooling water by means of a pump 6 by using a radiator 4 or a cooler 5, thereby constituting a mercury lamp device used for sterilizing foods or the like. As a result, it is possible to achieve a high intensity of ultraviolet radiation depending on the ratio between the average temperature of the cooling water and the output of ultraviolet rays. Moreover, it is possible to stabilize starting characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a high-output low-pressure mercury lamp used for surface sterilization of foods or their packaging materials.

Low-pressure mercury lamps conventionally used as germicidal lamps are generally the same as fluorescent lamps with the phosphor removed, and have relatively low input and output. For example, the input power of GL-15 specified in JIS is approximately 0.4 W/ctn, and the ultraviolet radiation output is approximately 9' or 5 mW/cnI.

On the other hand, recently, there has been a demand for higher output low-pressure mercury lamps due to the need for high-kill, high-ability sterilization.

On the other hand, simply increasing the input power of the conventional low-pressure mercury lamp as described above will not only raise the tube wall temperature, but also increase the mercury vapor pressure inside the tube, resulting in a decrease in the ultraviolet output as shown in Figure 1A. There was a problem.

Therefore, in response to the demand for higher output, we
A U-shaped high-output low-pressure mercury lamp having a mercury pressure control device was developed as described in Japanese Patent Publication No. 86 and Japanese Patent Application Laid-Open No. 54-71887.

Such low-pressure mercury lamps have the advantage of being able to obtain a high ultraviolet output with an input of about 5 W/α, but on the other hand, they have the following drawbacks.

In other words, since the pressure of mercury in the tube is made to reach an equilibrium state when the lamp is turned on, the warm-up time t1 for starting the lamp is approximately 30 minutes long, as shown in Fig. 2, and the pressure remains constant after starting. At time 12 (approximately 30 minutes), the ultraviolet output is unstable as shown in the figure. In addition, since a structure is used to cool the area around the electrodes of the discharge lamp and the fishing gear that houses the discharge lamp, the structure is not only complicated and expensive, but also difficult to handle when the lamp is large. It was also inconvenient. For example, if we take a U-shaped discharge lamp with a total input of 800W, as shown in the third prisoner, the total length of the discharge lamp is 1120m, and the size of the lamp that houses this discharge lamp is 1300mm long, 120mm wide,
The height is 125.

The present invention has been made based on the above points, and has a high purple sunset.
It can give a 4-wire output, and the 1-wire output while the light is on is very stable and the starting time is known.The structure is simple and economical, and it is suitable for use with discharge lamps and fishing equipment. The purpose of the present invention is to provide a complete set of IM pressure mercury lamps that have numerous advantages such as being able to be used in various forms.

FIG. 4 schematically shows an output-type low-pressure mercury lamp according to the present invention and the entire apparatus for lighting it. In the figure, 1 is a low-pressure mercury lamp that emits ultraviolet rays. This low-pressure mercury lamp 1 has, for example, a quartz tube with cold cathodes hermetically sealed at both ends, and about 50 square meters of water inside the tube. The low-pressure mercury phantom 1 is housed in a water-cooling jacket 2, and the arc tube surface mj of the low-pressure mercury phantom 1 is directly cooled with water. in this case,
The average temperature of the cooling water is maintained at 30-50°C. Figure 5 shows the relationship between the average temperature of the cooling water and the relative value of the ultraviolet output.As is clear from this figure, when the average temperature of the cooling water is outside the above range, the relative value of the ultraviolet output decreases. If it is less than about 80, it becomes impractical. As a means of keeping the average yield of intoxicating water within the above range, for example, as shown in the dotted line in Figure 91, cooling water tack 3 is cooled with tap water or well water, and cooling water tack 3 is cooled with tap water or well water. It is better to use a cooler or cooler 5. In addition, 6 indicates a pop for pouring water.

In this way, by storing the low-pressure mercury lamp 1 in the water-cooling jacket 2, cooling the tube surface with water contact, and controlling the average temperature of the cooling water within an appropriate range, the oil discharge and lamp input can be greatly reduced. Can you sell the UV output? FIG. 1B shows the relationship between the phantom input and the ultraviolet output for the radiation source 1 constructed as described above. As is clear from this figure, according to the present invention, by setting the input power of the five discharge lamps to 2 to 8 W/cm, it is possible to obtain a higher ultraviolet radiation intensity than that of the conventional low-pressure mercury lamp. If a water-cooled structure as in the present invention is not adopted under the above-mentioned input range, the temperature of the arc tube and the mercury vapor pressure inside the tube will be extremely high, and the ultraviolet output and life performance will be significantly reduced. On the other hand, if a water-cooled structure is adopted, the transmittance of ultraviolet rays will decrease slightly, but the increase in efficiency will more than compensate for this and high output can be obtained. Further, according to the present invention, it is possible to obtain a discharge lamp in which the ultraviolet output during lighting is extremely stable, since the time required for stabilization after starting is known. FIG. 6 shows the relationship between the lamp lighting time and the relative value of the ultraviolet output. As is clear from this figure, the discharge lamp according to the present invention reaches its maximum output in about 10 minutes after starting, and the ultraviolet output hardly changes during lighting. Furthermore, according to the present invention, it is possible to make a discharge lamp or a lamp 't/J1 type. For example, if we take a discharge lamp with a total input of 800W (2 400W lamps stored), the total length of the discharge lamp is 870ffl+, as shown in Figure 7.
The size of the lamp that houses two lamps is 1150mm long, 120mm wide, and about 50cm wide, making it smaller than the one shown in Figure 3.

Specific examples of the present invention are as follows.

A low-pressure mercury lamp is a quartz tube with a diameter of 20 m++, with cold cathodes placed at both ends of the tube and sealed with a distance of 750 m between the electrodes.
A device filled with mV of mercury and 1 torr of argon gas was used. The total input was 350W, and the input per electrode distance was 5W/sub. This was housed in a water cooling jacket with an inner diameter of 24 tmn, and the average temperature of the cooling water was set at 42°C and maintained at this temperature. The ultraviolet radiation intensity of this lamp was 4F3W/d.

As described above, according to the present invention, it is possible to obtain a high-output low-pressure mercury lamp* that can achieve the intended purpose.

[Brief explanation of the drawing]

Figure 1 is a comparison diagram of the input and ultraviolet output characteristics of the low-pressure mercury lamp according to the present invention and the conventional low-pressure mercury lamp. Fig. 4 is a diagram of the lighting device of the low-pressure mercury lamp according to the present invention, Fig. 5 is a diagram of the relationship between cooling water temperature and ultraviolet output of the low-pressure mercury lamp, and Fig. 6 is a diagram showing the relationship between the lighting time and the ultraviolet output. Figure 7 is a diagram showing the relationship between ultraviolet output and the external dimensions of the low-pressure water button and lamp according to the present invention. 1" Jl (hr,) Fang 7 figure procedure sleeves (in 1982, 2//day also Director General of the Permanent Office Kazuo Wakasugi Stable 1, Indication of the case 1989 Percent liver application No. 186352 2 Name of the invention: High-output type low-pressure water trowel lamp 3, and its relationship with the intelligence of the person making the correction Japanese patent applicant: 7 Jr. Address: 3-12-4 Shiba, Minato-ku, Tokyo 105 January 11, 1980 (Delivery date = January 3, 1981)
5. Subject of correction: 11゜

Claims (1)

[Scope of Claims] fil A low-pressure mercury lamp that emits ultraviolet rays is housed in a water-cooling jacket that is transparent to ultraviolet rays, and the surface of the arc tube of the low-pressure mercury lamp is directly cooled with water, and the average temperature of the cooling water is maintained at 30 to 30°C.
A high-output low-pressure mercury lamp characterized by being configured to maintain a temperature of 50°C. (2) The high-power low-pressure mercury lamp according to claim 1, wherein the input power per 1 crn distance between the electrodes of the low-pressure mercury lamp is 2 to 8 W.