JPS61263690A - Method and device for sterilizing fluid by using ultravioletbeam - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for sterilizing water, and more particularly to a sterilization apparatus and method using ultraviolet light generated by a laser.

(Conventional technology) Ultraviolet light is known as a disinfectant for water.

In the past, it was common to provide a series of banks of ultraviolet light pulp and to flow the water to be treated over the surface of the pulp. This method has a number of drawbacks.

First, the intensity of ultraviolet light changes depending on the distance from the pulp surface. Therefore, in order to provide sufficient intensity of ultraviolet light to all of the water passing through the pulp,
Either the pulps had to be placed in close proximity or special pulp arrays had to be used. Even with such an approach, the flow of water through the pulp had to be relatively slow to ensure that the water received an adequate amount of ultraviolet light. Also, placing the pulps in close proximity created a significant water head. Second, pulp tends to film or become cloudy, which reduces the intensity of the ultraviolet light. One solution to this problem is to periodicize the pulp. The second solution to this problem is to minimize film losses by providing equipment that can be easily replaced and cleaned.
The solution was to increase the intensity of the ultraviolet light above that initially required so that even after the pulp was coated, a suitable intensity of ultraviolet light was still obtained.

Third, bacteria attached to suspended particles are
If the particles are shielded from the light source, there is a possibility that they will not be exposed to ultraviolet light.

There are various sources of ultraviolet light in addition to the pulp or lamps currently commonly used for sterilization. One of the light sources capable of emitting light in the ultraviolet region is a laser using an appropriately selected laser excitation gas. The use of a laser that generates ultraviolet light for sterilizing wastewater has not been previously proposed. The laser determines the flow rate, or turbidity,
It has been found to have operational advantages including the ability to control strength in relation to a number of operating conditions such as the properties of water or other fluids such as organic content. Lasers can generate high-intensity ultraviolet light, which can increase the water flow rate, reduce head loss, adapt to highly turbid water, and prevent bacteria from being exposed to ultraviolet light. reduce sex.

The inventors have discovered a method for efficiently and effectively using lasers in water sterilization. The germicidal ability of lasers emitting in the ultraviolet spectrum consists primarily in killing bacteria by direct contact rather than secondary photochemical effects. Although these side effects may have the effect of killing bacteria, they have only a negative effect in the sterilization process. It can also be used to sterilize liquids, both water-based and non-water-based, and common fluids containing gases such as air.

SUMMARY OF THE INVENTION In its broadest sense, the present invention includes a method and apparatus for sterilizing fluids comprising passing a stream of liquid through a laser beam emitting light in the ultraviolet region. sterilization, and is suitable for using a gas laser whose average intensity of light can be adjusted according to the pulsation rate. The pulsation rate can be varied from slow to very fast resulting in an essentially constant beam. The pulsation rate may be adjusted in response to changes in the flow rate of the fluid stream passing through the laser beam and in response to changes in the turbidity of the water being treated. As a result, the intensity of the ultraviolet light can be controlled to the intensity required by the operating conditions or characteristics of the fluid being treated.

Further in accordance with the present invention, there is provided a method and apparatus for varying the flow rate of a stream while maintaining a constant intensity of the ultraviolet beam.

The laser beam according to the invention has a substantial width and the flow passes through an essentially fixed beam.

The cross section of the flow can be chosen to correspond to the area of the beam and to obtain a light scattering effect when the beam impinges on the suspended particles.

Further in accordance with the present invention, there is provided a method and apparatus for reflecting a beam from the surface of a bath for flowing fluid. Reflection and scattering from the oak surface limits the spread of the beam by particles suspended in the fluid and reduces the cross-sectional area of the beam along the length of the region where the beam and fluid interact. Compensate for changes in the beam so that a nearly constant intensity can be maintained.

In one embodiment of the invention, the angle of incidence of the beam relative to the flow is adjusted in response to changes in fluid turbidity.

In particular, according to the invention there is provided a method for sterilizing water, comprising the steps of providing a water stream to be treated, generating a gas laser beam emitting ultraviolet tilted light, and directing this beam into the water stream. Furthermore, the method of the present invention includes the step of increasing the pulsation rate in proportion to the increase in the flow rate of the water stream or in proportion to the turbidity of the water stream. The method of the present invention also preferably comprises the step of sensing the amount of visible light scattered by particles suspended in the water so as to be varied in relation to the change in the amount of visible light scattered by the particles suspended in the water. The method may include changing the dimensions, particularly the length, of the laser beam in response to changes in the properties.

The invention also provides an apparatus for sterilizing water by exposing it to ultraviolet light, the apparatus comprising:
A water tank equipped with an inlet pipe and an outlet pipe, means for controlling a cross section of water flowing between the inlet pipe and the outlet pipe, and a gas laser that generates a beam that fills the cross section of the water and emits light in the ultraviolet region. Be equipped. The device of the present invention also includes means for detecting visible light scattered by particles suspended in water and control means adapted to reduce the cross section of the water in accordance with the amount of detected visible light. It may include means for adjusting the operation. The device of the invention also includes means for controlling the pulsation rate of the laser and means responsive to the flow within the bath to adjust the control action, or detecting visible light reflected by particles suspended in the water. and means for adjusting the pulsation rate control operation in response to the amount of visible light. Furthermore, the apparatus of the invention may include means for varying the length of the laser beam (measured along the direction of fluid flow) in response to changing conditions of the sensed fluid.

The tank can be in the form of a channel or a weir. In either case, the laser beam is emitted in a direction transverse to the water stream. The water flow can be shaped by varying the width of the channel or by varying the height of the weir so that the cross section of the water flow matches the shape of the beam which is made to widen as it passes through the drainage. The stream may also be configured to narrow in its cross section to compensate for beam changes in turbid streams.

A primary object of the present invention is to provide a method and apparatus for sterilizing water and other fluids by using ultraviolet light without contact between the ultraviolet light source and the fluid.

It is further an object of the present invention to provide a method and apparatus for varying the ultraviolet light intensity of a light source in response to operating conditions such as flow rate and in response to water or fluid conditions such as turbidity. be.

It is yet another object of the present invention to provide a gas laser device for controlling the laser pulsation rate in response to the turbidity or flow rate of the fluid to be treated.

These objects and advantages will become clear from the description below.

(Example) Examples of the present invention will be described in detail below with reference to the drawings.

Referring to FIGS. 1-3, a variation of a pulsating gas laser of the type described in U.S. Pat.

The laser 10 comprises a pair of electrodes 11, 12 each forming one plate of a capacitor.

The electrodes 11.12 are respectively arranged on the inner surfaces of a pair of dielectric plates 13.14, which are mounted parallel to each other and on both sides of a single chamber assembly consisting of chamber halves 15.16. Fixed on top. The chamber halves 15,16 together define a cavity of an oval chamber 17 extending in the longitudinal direction of the chamber assembly. The electrodes 11 . 12 are bent towards each other inside the chamber 17 so that each end 18 . 19 of the electrode 11 . 12 faces spaced apart within the chamber 17 . The chamber 17 is connected to an evacuation pump 20 and is supplied with gas through a regulating pulp 22 from a gas source 21, which may be a pressure cylinder.

A pair of conductive plates 25 are provided on the outer surfaces of the dielectric plates 13 and 14.
．． 26 is formed. These conductor plates 25 and 26 are both grounded. The electrodes 11 , 12 are connected to each other through an induction coil 27 , and the electrodes 12 are connected to a high-voltage DC voltage source 28 through an induction coil 29 . High voltage DC voltage source 28 charges electrode 12 and then charges electrode 11 through coil 27 .

Spark gap switch 30 is connected to electrode 11 and periodically grounds electrode 11 when spark gap switch 30 is activated. When electrode 11 is suddenly grounded, a very high voltage is developed in the gap between the electrode ends 18.19 and electrons flow between the electrode ends 18.19. If chamber 17 is filled with a lasable gas such as nitrogen, the electron flow will cause lasing and a laser beam with a certain width will be produced. The laser beam is shown in phantom 31 in FIGS. 1 and 2. By selecting the appropriate gas, the laser 10
generates a beam 31 emitting light in the ultraviolet range. Nitrogen is one such gas. The beam is quite wide (W
) and D) to a considerable depth. The smallest dimension of the beam, called length L), can also be measured and has the advantage of being manipulated, as will be explained below. This ``length'' is so called because it measures the length of time that the liquid is exposed to the beam. The shape of the beam, which has a significant width, is quite wide in contrast to a typical laser beam, which has a small beam diameter of light.

In the laser 10 used in the present invention, the excitation voltage generated by the high voltage DC voltage source 28 can be as high as 30,000 volts at a chamber 17 pressure of 100 torr. This makes the width approximately 1 inch (2.54 cm),
A laser beam 31 having a length of 2 feet (61 cm) is generated.

The spark gap switch 30 periodically generates an arc by using an oscillator 35 in a well-known manner. In the present invention, the arc generation rate of the spark gap switch 30, that is, the pulsation rate of the laser 10 is controlled by the operating speed. adjusted to the conditions and conditions of the fluid being processed.

This modification is effected by an oscillator 35 controlled by a photocell 36 which senses the turbidity of the fluid being treated, as will be described in detail below. Another arrangement for controlling laser pulsation is shown in FIG.

In FIG. 3, the high voltage DC rectifier 28' is connected to the AC power source through a potentiometer 37 which is adjusted by an analog controller 37 which is responsive to the amount of light detected by a photocell 36.

A change in the amount of light detected will change the amperage to the high voltage DC rectifier 28', thereby adjusting the rate at which electrodes 11, 12 are charged. If the charging speed changes, the laser pulsation speed changes.

FIG. 3 also shows a mechanism for adjusting the spark gap as the spark gap switch electrodes wear. Spark gap switch 30'
One contact 39 is provided at one end of a screw punch 40 which is screwed into a screw block 41 and has a pinion gear 42 attached thereto. Pinion gear 42 meshes with gear 43 mounted on the output shaft of motor 44, which is controlled by motor controller 45 responsive to the output voltage of high voltage DC rectifier 28'. Sparks due to electrode wear
As the gap increases, the charging voltage that arcs across the spark gap also increases. This increase in voltage is detected by motor controller 45, so that motor 44
The gap is reduced by moving the contact 39 to the fixed contact side. Therefore, a predetermined charging voltage for the laser is maintained, thereby ensuring constant laser pulses due to discharge.

Referring to FIGS. 4 and 5, laser 10 is shown mounted in conjunction with a flume configuration designated 50. Referring to FIGS. The water channel 50 includes a basin having a pair of upright side walls 51.52, the side walls 51.52 widening at both ends and having an inlet 53 in communication with an inlet tube 55 and an outlet tube 56, respectively.
and a lead-out portion 54 is formed. The middle of the widened portions of the side walls 51,52 define regions parallel to each other and of constant cross-sectional area. The baffle plate 57 is the introduction pipe 55
and is provided facing the outlet pipe 56. Waterway 50
One dam plate 60 is provided over the entire cross section of the
This dam plate 60 has side walls 51 .
52 is attached to a shaft 61 supported by bearings 62 disposed at the opposing tops of the shafts 52. A counterweight 63 projects above the shaft 61. The dam plate 60 controls the water flow in the water channel 50, and is pivoted when there is a significant change in the flow velocity. The dam plate 60 maintains the water depth within the waterway 50 and minimizes the distance that the laser beam travels through the air. In the drawing, the distance between the laser 10 and the surface of the water is exaggerated. The laser 10 is attached to the top of the waterway 50, and the laser beam passes through the waterway 50 and is emitted downward into the water. A mirror surface 65 that reflects the laser beam is provided along the bottom surface of the water channel 50.

The laser beam is emitted over a constant cross-sectional area of the water channel 50 so that the water flowing through the water channel 50 passes through the beam and all water is exposed to the beam. Exposure to ultraviolet light kills bacteria in the water and sterilizes the water. Since the total amount of UV radiation is important, the intensity of the laser beam is preferably adjusted to reflect changes in the flow rate of water passing through the beam; the intensity of the laser beam adjusts the pulsation rate of the laser. It can be controlled by

This adjustment can be achieved by adjusting oscillator 35 or potentiometer 37.

In the embodiments of FIGS. 4 and 5, the dam plate 60
responds to the water flow flowing through the water channel 50, and its angle with respect to the vertical direction changes in response to changes in flow velocity.

That is, as the flow velocity increases, the dam plate 60 is moved more from the vertical direction. The displacement of this dam@60 is determined by the resolver 66 connected to the shaft 61 of the dam plate.
detected by. Resolver 66 sends a signal to oscillator 35 or potentiometer 37, which changes the pulsation rate of the laser. The higher the flow rate, the faster the laser must be pulsed because the exposure time to the laser beam is reduced.

Instead of the dam plate 60 and the resolver 66, the flow velocity can be detected by measuring the depth of the waterway using a known sonic depth meter. Water depth is proportional to flow rate and a depth gauge can be used to send a signal to oscillator 35 or potentiometer 37.

The inventors have determined that it is possible to sterilize fluids, particularly water, by using lasers that generate ultraviolet radiation, which is particularly sensitive to suspended solids, which are particularly susceptible to fluid turbidity. is believed to reflect and diffuse the laser beam. Because the laser beam must penetrate significant depths of water, if the water is significantly turbid, parts of the water stream relatively far from the laser beam's point of entry into the water stream will receive only low levels of UV radiation. You will not be able to do so. This is because the laser beam is significantly dispersed and diffused until it reaches a part far from the incident point. Therefore, it is highly desirable to increase the intensity of the laser beam when the turbidity increases, as shown in FIG. This can be detected by using a photocell sensor that responds to the amount of light reflected by the sensor. The smaller the amount of light, the greater the turbidity. Alternatively, a similar photocell that responds to the amount of visible light reflected and scattered by suspended particles in the water may be simply placed toward the surface of the water, in which case:
The more solids are suspended, the more light is detected; in either case, a photocell is used to control an oscillator 35 or a potentiometer 37, which controls the pulsation rate of the laser 10.

Instead of adjusting the pulsation rate according to the detected change in turbidity, the angle of incidence of the laser beam incident into the water stream can also be adjusted according to the change in turbidity. Fifth
The illustrated laser 10 has a sidewall 51.5 at one end thereof.
2 is mounted on a pivot shaft 68 supported by a bearing block mounted on the top of 2. A sector gear 69 having a gear cutting pitch circle centered on this pivot shaft 68 is a laser 10.
installed on top. Pinion 70 is sector gear 69
The pinion 70 is driven by a motor reducer 71 responsive to signals from the photocell. When turbidity is high, rotation of pinion 70 in response to the detected amount of light displaces laser 10 to a position where the beam becomes more vertical. In that position,
The beam reflected from the bottom surface is transmitted upward for a certain distance, so that the area of minimum beam intensity is exposed to the beam passing through the same path twice.

In the embodiment shown in FIGS. 4 and 5, an independent flow meter consisting of a dam plate 60 and a resolver 66 is used, and an independent turbidity sensor consisting of a photocell 67 is used.

If the laser sterilizer is installed as part of a larger wastewater treatment facility, as is normally the case, this treatment facility will be equipped with flow meters and turbidity meters to control other parts of the treatment process. , in which case existing flow meters and turbidity meters can be used to control the operation of the laser in the present invention.

There are other conditions of the treated fluid that can be sensed and used to control the intensity of the laser beam.

For example, armpit carbon meters are known to provide an immediate indication of the organic content of water or other fluids. The amount of organic matter is related to turbidity or bacterial content.

The residual carbon meter reading may be converted to a signal that controls the laser pulsation rate in a manner similar to a photocell 67 or resolver 66 or other sensor for sensing fluid conditions or properties.

In the configuration of FIGS. 4 and 5, the side walls 51, 52 of the channel
are upright and parallel to each other in the narrow central part of the channel. In practice, the laser beam tends to spread out as it passes through the water to be treated. If the intensity of the ultraviolet light is high enough and the turbidity of the water or other fluid is low enough, the tendency of the beam to spread as it passes through the fluid can be used to advantage. As shown in FIG. 6, the central portion of the channel may be configured such that its side walls 72,73 are wider at the bottom than at the top of the channel.

The larger cross-sectional area provided by this configuration allows more water or other fluid to be processed per unit time.

In highly turbid wastewater, scattering from suspended particles reduces the intensity of UV light, so that when it reaches the bottom of the stream, its ability to kill bacteria is significantly reduced. A bath having the cross-section shown in FIG. 7 can be used to uniformly increase the intensity of the ultraviolet radiation throughout the depth of the water stream. In FIG. 7, the side walls 74, 75 of the central portion of the channel are arranged so that they are narrower at the bottom than at the top of the channel, forming a Williamson cone.
Scattering effects caused by suspended particles tend to concentrate the beam towards the bottom. This tendency is significantly enhanced by making the entire inner surface of the tank a mirror surface. Thus, in the implementation of FIG. 7, the inner surfaces 74', 75 of the sidewalls
' together with the inner surface 76' of the bottom wall may be formed of a reflective material, such as an aluminum sheet, so that the laser beam is reflected from the inner surface of the side wall and is scattered by the suspended particles, thereby trapping bacteria. Ultraviolet light strong enough to kill reaches the narrowed bottom of the waterway.

Advantageously, all internal surfaces of all vessels in embodiments of the invention are reflective surfaces that reflect the beam, allowing advantageous scattering effects necessarily resulting from suspended particles.

Referring to FIGS. 8 and 9, an embodiment of the invention is shown with a weir structure including a box-shaped tank 80 with an inlet pipe 81, an outlet pipe 82, and an intermediate weir 83. The laser 10 is mounted on one side wall of the tank 80, and the laser beam is emitted downward so as to be concentrated on an inclined mirror 85.

This mirror 85 reflects the beam along the upper edge of the weir 83. In the embodiment shown in FIGS. 8 and 9, the upper edge of weir 83 is horizontal and the beam is reflected by mirror 85 into weir 83.
pass through a passage parallel to the horizontal top of. On the opposite bank of weir 83 is the second
A mirror 86 is arranged to direct this laser beam to the photocell 8.
The pulsation speed is controlled in relation to the amount of light detected by this photocell 87 .

As seen in the embodiments of FIGS. 8 and 9, weir 83
A laser beam 8 whose cross section of the water flow exceeding
4, all the water passing between the inlet pipe 81 and the outlet pipe 82 is exposed to ultraviolet light.

FIG. 10 shows a modification of the embodiment of FIGS. 8 and 9 in which the upper edge 88 of the weir 83' is lowered away from the mirror 85.

As a result, the water crosses the weir 83' with a wedge-shaped cross section. The wedge-shaped cross-section of this water stream is chosen to match the changes that laser beam 84 undergoes as it passes through the water. That is, the laser beam tends to spread out as it passes through the water. The embodiment of FIG. 10 also has the advantage that when the laser beam reaches the surface of the water, if the angle of incidence on the mechanism exceeds the critical angle, the laser beam will be reflected back into the water. This effect is illustrated in FIG. 10 by arrow 89, where the laser beam is confined within the water flow flowing over weir 83'. A further variation of the shape of the weir is such that the upper edge of the weir rises away from the mirror, so that the cross-section of the water narrows away from the mirror. In this case, the same effect as the embodiment shown in FIG. 7 can be obtained. The embodiment of FIG. 10 also uses a photocell 90 to sense the turbidity of the water and adjust the pulsation rate of the laser beam accordingly. However, unlike photocell B7 in FIG. 8, which is adapted to detect the laser beam after passing through water, photocell 90 detects the amount of scattered visible light reflected from particles suspended in the fluid. It has been made to look like a stone.

In the embodiments of Figures 4-7 and 8 and 9, the oak is open to the outside world. This tank, whether it is a waterway or a weir, should be covered to exclude ambient light. Ambient light has the power to revive the bacteria, so that they are not killed but grow again. I end up.

Referring to FIG. 11 and FIG. 12, the introduction tube 9 at both ends
6 and an embodiment using a helical tube 95 having an outlet tube 97 is shown. Water flowing in from the inlet pipe 96 flows into the outlet pipe 9.
It flows in a spiral while reaching 7. A fixed laser 10 with a beam focused along the long axis of tube 95 is mounted near the output end. The output end is provided with a transparent end wall 98 through which the beam can pass. A mirror surface 99 is formed on the inner surface of the introduction end of the tube 95 to reflect the beam, and a photocell 100 is placed near the laser 10 to detect the amount of visible light. The embodiments of Figures 11 and 12 use a fixed laser beam through which the flow of water or other fluid is forced. However, in this embodiment, the flow encounters the beam at multiple points along the length of the beam, thereby increasing the time that the water is exposed to ultraviolet radiation.

All the embodiments described above include means for adjusting the intensity of the laser beam by adjusting the pulsation rate. It is also possible to adjust the dimensions of the beam to accommodate changes in fluid conditions or properties. Figure 13 shows how to change the beam geometry, especially the smallest dimension, L.
) is shown. In the configuration of FIG. 13, laser 10 is mounted on a pivot shaft 68 like the embodiment of FIGS. 4 and 5. The angle of laser 10 is varied by pinion 70 meshing with sector gear 69. A laser beam 105 generated from laser 10 is directed to lens 106, which is a double concave diverging lens. lens 1
The effect of 06 is to expand the length of the beam 105 and make the beam 10
5' has an increased length. The water to be treated passes through this increased length beam 105'.

The length of beam 105' is the length of beam 10 that impinges on lens 106.
5' angle. This angle is laser 10
is adjusted by adjusting the relative angle of.

A sensor 107, such as a total organic carbon meter, is placed in the water being treated. Sensor 107 controls the operation of motor 71 to generate a signal that is used to change the angle of laser IO in response to changes in the detected organic content of the water. Beam 105 as the organic content increases
The length of ' is also increased, which increases the residence time of water passing through beam 105' within beam 105' and increases the opportunity for bacteria to be exposed to ultraviolet light.

Similar adjustments can be made for changes in turbidity.

Even if the total photon quantity is the same, the probability of contacting bacteria increases if the water passing through the length of beam 105' is a turbid stream.

Above, a gas pulsating laser was exemplified as a preferred ultraviolet light source. The term is meant to also include lasers, commonly known as continuous lasers, which have short pulse intervals and therefore appear continuous due to such high pulsation rates.

So-called continuous lasers do not have intensity adjustment like gas lasers, which have lower pulsation rates.

However, such lasers can be advantageously used, for example in the embodiment of FIG. 13, in which the intensity of the laser beam is kept constant and the beam geometry is varied in relation to the operating conditions or the properties of the fluid. It can be done.

EFFECTS OF THE INVENTION It should be noted that in each of the above-described embodiments, the source of the laser beam is not in contact with the water or other fluid being treated; this is because the ultraviolet radiation that water typically flows over There are significant advantages compared to using pulp. Because there is no contact between the laser beam source and the water, the laser beam source is not clouded or coated by impurities in the waste water, and there is no need to continually clean the device.

Although nitrogen can generate light in the ultraviolet region when excited by a laser, nitrogen is not a preferred gas when used in the laser of the present invention.The results of measuring the amount of laser light per unit input power through numerous exciser tests. It was determined that the most efficient gas was obtained by using fluorine-krypton efcimer. This F-cimer generates light with a wavelength of 249 nanometers, and
Experiments have shown that approximately 90% of E. coli bacteria are destroyed at a radiation dose of 0.1 joule per square centimeter, and 99% or more is destroyed at a radiation dose of 0.3 joule per square centimeter.

Using lasers provides an excellent source of intense ultraviolet light. As mentioned above, the ultraviolet light source is controlled, regulated and varied to provide limited sterilization by killing bacteria. This is in contrast to the conventional use of ultraviolet light, which was simply used with the crude hope that the water or other fluid being treated would be exposed to sufficient ultraviolet light to kill germs.

The flow rate of water through the device of the present invention can be significantly higher than in configurations using conventional ultraviolet bulbs.

As a result, the head loss is considerably reduced and the high flow rate tends to self-clean the surface of the tank through which the fluid flows. This high flow rate also results in the inversion of suspended particles.

This inversion of the particles, combined with the increased intensity of the ultraviolet light and the reflection of the laser beam from the side walls or surfaces of the bath, reduces the possibility that bacteria attached to the suspended particles will not be exposed to the ultraviolet light.

On the contrary, the entire surface of the suspended particles will be exposed to ultraviolet light.

By using a laser that emits light in the ultraviolet region, it is possible to sterilize more turbid fluids than with bulbs in conventional methods. It is better for the fluid to be somewhat turbid; in conventional devices, turbidity is always detrimental to successful operation.
Adjustments are made to the pulsation rate, intensity or angle of the beam in relation to changes in turbidity.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view of a gas laser used to carry out the present invention, Fig. 2 is a plan view of the laser shown in Fig. 1, and Fig. 3 shows a modification of the laser shown in Fig. 2 with a spark gap switch. a partial plan view shown with controlling circuitry and power supply;
FIG. 4 is a perspective view showing the configuration of a water channel for sterilizing fluid using the laser shown in FIGS. 1 to 3, FIG. 5 is a vertical cross-sectional view of the water channel shown in FIG. FIG. 7 is a sectional view of the deformation of the waterway shown in FIG. 5, and FIG. 8 is a perspective view showing the configuration of a weir for sterilizing wastewater using the laser shown in FIGS. 1 to 3.
Figure 9 is a longitudinal cross-sectional view of the weir shown in Figure 8, Figure 10 is a partial cross-sectional view showing the deformation of the weir, and Figure 11 is a treatment of wastewater flow using the laser shown in Figures 1 to 3. Cross-sectional view of a helical tank for,
12 is a plan view of the helical vessel of FIG. 11, and FIG. 13 is a partial view showing a modification of the apparatus of FIGS. 4 and 5 used to adjust the geometry of the laser beam. In the drawing, 10 is a laser, 35 is an oscillator, 36.6
7.87.90, 100 is a photocell, 37 is a potentiometer, 50 is a water channel, 55.8196 is an introduction pipe, 56
．． 82.97 is an outlet pipe, 60 is a dam plate, 66 is a resolver, 80 is a tank, 83 is a weir, 84 is a laser beam, 85
．． 86 is a mirror, 95 is a spiral tube, and 106 is a lens.

Claims (1)

[Claims] 1. A method for producing ultraviolet light characterized by preparing a flow of fluid to be treated, generating a laser beam emitting light in the ultraviolet region, and guiding this beam into the flow of said fluid. Fluid sterilization method used. 2. The beam is generated as a pulsed gas laser beam, and the property of the fluid is sensed and the pulsation rate of the laser beam is adjusted in proportion to changes in this property. The method described in paragraph 1. 3. The method according to claim 2, wherein the characteristic of the fluid is the flow rate of the fluid, and the pulsation rate is increased in proportion to an increase in the flow rate of the fluid. 4. The method of claim 2, wherein the characteristic of the fluid is turbidity, and the pulsation rate is increased in proportion to an increase in the turbidity. 5. The method according to claim 1, characterized in that the angle of incidence of the beam with respect to the flow is changed in response to changes in turbidity of the fluid to be treated. 6. means for providing a flow of fluid to be treated and means for generating a laser beam emitting light in the ultraviolet region;
and means for guiding the beam into the fluid flow. 7. A fluid tank (50, 80) having an inlet pipe (55, 81) and an outlet pipe (56, 82), and means for controlling the cross section of the fluid flowing between the inlet pipe and the outlet pipe ( 60
, 83) and a beam (
A pulsated gas laser (10) generating
7. The apparatus according to claim 6, wherein the beam is disposed between the inlet tube and the outlet tube and emits light in the ultraviolet region. 8. Device according to claim 7, characterized in that the bath (50) is provided with a reflective surface (65) for reflecting light from the beam. 9. The laser is connected to a flow rate response means (60, 6) in the tank.
8. Device according to claim 7, characterized in that it comprises pulsation rate control means (35, 37) with 6). 10. The laser has a pulsation rate control with means for detecting visible light reflected by particles suspended in the water and adjusting the pulsation rate control operation in response to the amount of visible light. 8. Device according to claim 7, characterized in that it comprises means (35, 37).