JP3318500B2 - Ultrasonic cleaning equipment for underwater measuring instruments - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic cleaning apparatus, and more particularly, to a measuring instrument used while immersed in water, and a part of the measuring instrument located in a relatively narrow space. The present invention relates to an ultrasonic cleaning device for cleaning continuously or periodically.

[0002]

2. Description of the Related Art In a measuring instrument used in a state of being immersed in water, such as a fluorometer, a turbidity meter or a PH meter, an accurate measurement result is generally obtained when a sensitive part or the like becomes dirty. Can not be. In particular, in the case of a measuring instrument that outputs measurement results every moment when it is immersed in water for a long period of time, sensitive parts etc. gradually become dirty due to adhesion of suspended substances etc. in water, and the measurement output becomes less accurate There is a problem.

[0003] Therefore, in this type of measuring instrument, a wiper using a rubber blade has been conventionally provided for preventing contamination of a sensitive portion, etc. Measures have been taken such that ultrasonic cleaning is attached to a measuring instrument, and a required portion such as a sensitive part is ultrasonically cleaned continuously or periodically.

[0004]

Among the above-mentioned conventional countermeasures, the one using a wiper has the drawback that the rubber blade has a long service life, the structure is complicated, and only a relatively flat surface can be cleaned. In addition, for those that spray the water stream to the required area, it is necessary to take clean water for washing from a tap of the tap, etc.
There are problems that the device becomes large and the cost increases.

On the other hand, although there is no such problem when using an ultrasonic cleaning device, the ultrasonic cleaning device used for this kind of application is usually a disk-shaped ultrasonic vibrator made of a piezoelectric material. The ultrasonic cleaning device with such a structure is used to effectively clean required parts such as sensitive parts as shown below depending on the type and design of the measuring instrument. May not be possible.

That is, in ultrasonic cleaning, generally, dirt is removed from a portion to be cleaned by ultrasonic medium, that is, cavitation generated in water and vibration acceleration applied to water molecules. However, the cleaning effect is large. Is a position where the distance from the vibration surface (the interface between the diaphragm and the medium, hereinafter the same) is an odd multiple of 1/4 of the wavelength λ of the ultrasonic wave in the medium, and is attached to this type of measuring instrument. Unlike the ultrasonic cleaning equipment used together with a dedicated container for cleaning various parts, it is practically impossible to use the generated ultrasonic waves reflected from the water surface. Because ultrasonic waves transmitted into the water from the vibrating surface attenuate exponentially as the distance from the vibrating surface increases, the position of the vibrating surface should be as close as possible to the required cleaning part. Necessary distance between shielding is made to be an odd multiple of lambda / 4 is generated.

On the other hand, the cleaning effect differs depending on the frequency of the ultrasonic wave. For cleaning using cavitation, a frequency in the range of 15 to 50 kHz is generally used. It is known that an excellent cleaning effect can be obtained. In the case of an ultrasonic vibrator using a disc-shaped piezoelectric material, its diameter is naturally determined by the oscillation frequency.

For this reason, the part of the measuring instrument that needs cleaning is located inside a relatively narrow space,
In some cases, the ultrasonic transducer cannot be inserted into the space, but in such a case, it is necessary to adopt a structure in which the ultrasonic transducer and the diaphragm are arranged outside the space. As a result, there is a problem that the distance of the required vibrating portion from the vibrating surface becomes long, and an effective cleaning effect cannot be exhibited.

In order to solve such a problem, it is conceivable to increase the power supplied to the vibrator. In this case, however, it is necessary to increase the power of the oscillation circuit. There is a new problem such as an increase in the size of the device.

The present invention has been made in view of such circumstances, and increases the power input to a vibrator even when a required cleaning part in a measuring instrument used in water is located inside a narrow space. It is an object of the present invention to provide an ultrasonic cleaning device for an underwater measuring instrument that can obtain a large cleaning effect using ultrasonic waves of a desired frequency without using the ultrasonic waves.

[0011]

An arrangement for achieving the above object will be described with reference to FIGS. 1 and 2 showing an embodiment. An ultrasonic cleaning apparatus for an underwater measuring instrument according to the present invention comprises:
An apparatus having a disk-shaped ultrasonic vibrator 11 and a vibrating plate 12 fixed to the vibrator, which is mounted on a measuring instrument 20 used in a state of being immersed in water.
An ultrasonic cleaning device for cleaning a portion W located in a space S having a width smaller than the diameter of the vibrator 11 therein,
On the surface of the vibration plate 12 opposite to the surface fixed to the vibrator 11, there is provided a cylindrical resonance portion 13 having a smaller diameter than the vibrator 11 and having an outer diameter that can be inserted into the space S. It is characterized by having.

Here, the cylindrical resonance part 1 according to the present invention is used.
3 may be formed integrally with the diaphragm 12 or may be formed separately and fixed to each other. According to the above-described apparatus of the present invention, the vibration of the ultrasonic vibrator 11 is transmitted to the medium via the diaphragm 12 via the diaphragm 12 and then to the medium. That is, the distal end surface of the cylindrical resonating portion 13 becomes the vibration surface. Therefore, the ultrasonic vibrator 11 cannot be inserted into the space S where the required cleaning part W is located, and the vibrator 11 and the vibration plate 12 have to be arranged outside the space S. By inserting the cylindrical resonating portion 13 into the hole, the distance between the tip end surface and the required cleaning portion W can be made as small as possible, and can be set to an odd multiple of λ / 4.

[0013]

FIG. 1 is a longitudinal sectional view of an embodiment in which the present invention is applied to a fluorometer, and FIG. 2 is a diagram illustrating only an ultrasonic cleaning apparatus extracted therefrom, which is indicated by an arrow A shown in FIG. FIG.

In this example, a fluorometer 20 includes an LED inside a casing 21 having a watertight structure immersed in water.
Light-emitting device 22 composed of a light-emitting element such as a lens and a lens, and light-receiving device 2 composed of a light-receiving element such as a photodiode and a lens
3 is accommodated in a state where they face each other, and a groove-shaped space S having a width T communicating with the outside of the casing 21 is formed between the light emitting device 22 and the light receiving device 23. In addition, transparent glass 22a, 23a forming a light-emitting window and a light-receiving window on the walls on both sides of the space S on the casing 21 in a watertight manner via a sealing member such as an O-ring. The light from the light emitting device 22 is incident on the light receiving device 23 through the transparent glasses 22a and 23a.

With the above configuration, when the casing 21 is immersed in water, light from the light emitter 22 enters the light receiver 23 via the transparent glass 22a, the water in the space S, and the transparent glass 23a. The amount of light incident on the light receiver 23 depends on the degree of transparency of water in the space S, and the output signal from the light receiver 23 is a value representing the degree of transparency of water at the position where the casing 21 is immersed. This output signal is transmitted to the outside via a cable (not shown) drawn from the casing 21.

In this case, the surfaces of the transparent glasses 22a and 23a are always in contact with the water to be measured in use, but when a suspended substance or the like in water adheres to the surfaces of the transparent glasses 22a and 23a, As a result, the amount of light incident on the light receiver 23 is attenuated, and the output signal thereof does not show an accurate transparency. Therefore, each of the transparent glasses 22a, 23a
The surface of the transparent glass 22a, 23a needs to be continuously or periodically cleaned in a use state, and the surface of each of the transparent glasses 22a, 23a becomes a required cleaning portion W by the ultrasonic cleaning device 10 described below.

Above the space S, a support member 24 having a tapered through hole formed at the center is provided with a casing 2.
The ultrasonic cleaning device 10 is attached to the support member 24.

The ultrasonic cleaning apparatus 10 includes a disk-shaped ultrasonic vibrator 11 made of a piezoelectric material, and a disk-shaped vibrator 12 fixed to the vibrator 11. Has a cylindrical resonance portion 13 integrally formed so as to protrude from a surface opposite to a fixing surface of the vibrator 11. Here, the diameter D of the ultrasonic vibrator 11 is larger than the width T of the space S, and the outer diameter dimension d of the cylindrical resonance part 13 is smaller than the width T of the space S.

As shown in FIG. 1, the ultrasonic cleaning apparatus 10 has a plurality of through-holes formed in the vicinity of the outer periphery of the diaphragm 12 in a state where the cylindrical resonating portion 13 faces the space S and is inserted therein. It is screwed to the support member 24 via the hole 12a. It should be noted that an O-
A seal member such as a ring is interposed, thereby closing the through hole formed in the support member 24 in a watertight manner.

In the above-described embodiment of the present invention, the axial length of the cylindrical resonating portion 13 is determined by the tip surface of the cylindrical resonating portion 13 which is a vibration surface and the transparent glass 22a which is the required washing portion W. , 23a as close as possible, and the wavelength λ of the ultrasonic wave determined by the oscillation frequency of the ultrasonic transducer 11 and the speed of sound in water as a medium.
Is set to be an odd multiple of 1/4.

More specifically, the setting of this example is as follows. If the oscillation frequency of the ultrasonic vibrator 11 is 42 kHz and the sound speed in water is 1500 m / s, the wavelength λ is

[0022]

(Equation 1)

## EQU1 ## Therefore, λ / 4 is 0.893 cm, and L1 = 0.8 in order to obtain the most effective cleaning effect.
What is necessary is just to set the axial length of the cylindrical resonance part 13 to be 93 cm. In such a case, in this example, the radius of the transparent glass 22a, 23a is 1.75c.
m, and the optical path formed between them is
, L1 is larger than its diameter, is an odd multiple of λ / 4, and is as small as possible. As a result, L1 = 3λ / 4 = 2.
68 cm.

By the way, when an ultrasonic cleaning device having a structure in which only the disk-shaped diaphragm 12 having no cylindrical resonance portion 13 is fixed to the vibrator 11 is mounted on the fluorometer 20, the width T
Ultrasonic transducer 1 having an oscillation frequency of 42 kHz in the space S
1 is a distance of 5λ / 4 between the surface of the vibrating plate 12 which is a vibrating surface and the center of the required cleaning portion W because it cannot be physically inserted.
The cleaning effect cannot be made shorter than this, and the cleaning effect is greatly reduced with respect to the above-described embodiment.

In the above embodiment, an example is shown in which the diaphragm and the cylindrical resonator are integrally formed. However, the cylindrical resonator separately formed on the diaphragm is welded, adhered, screwed, or the like. May be fixed by the above-mentioned means.

Further, in the above-described embodiment, an example in which the present invention is applied to a fluorometer is shown. However, in the present invention, a required cleaning portion is located inside a relatively narrow space, and a desired frequency is required. It is applied to an underwater measuring instrument having a structure in which a transducer for generating ultrasonic waves cannot be inserted into the space, and exerts its effect. A PH meter and the like can be cited, and the present invention can be equally applied to them.

[0027]

As described above, according to the present invention, there is provided an ultrasonic cleaning apparatus which is used in water and which is mounted on a measuring instrument having a required cleaning portion inside a relatively narrow space.
The diaphragm is fixed to the disc-shaped ultrasonic vibrator, and the surface of the vibrating plate opposite to the fixing surface of the ultrasonic vibrator is smaller than the diameter of the ultrasonic vibrator, and the required cleaning part is A cylindrical vibrating part with an outer diameter that can be inserted into the space to be faced is provided, so that the tip surface of the cylindrical vibrating part, which is the vibration surface, can be as close as possible to the required cleaning part Thus, it has become possible to improve the cleaning effect by using ultrasonic waves of a desired frequency without increasing input power, as compared with a conventional cleaning apparatus of this type.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment in which the present invention is applied to a fluorometer.

FIG. 2 is a diagram illustrating only the ultrasonic cleaning device 10 in FIG. 1 extracted and viewed from a direction indicated by an arrow A in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ultrasonic cleaning apparatus 11 Ultrasonic vibrator 12 Vibration plate 13 Cylindrical resonance part 20 Permeability meter 21 Casing 22 Light emitting device 23 Light receiving device 22a, 23a Transparent glass 24 Support member S Groove space W Required washing part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B08B 3/12 G01D 21/00 G01N 1/00 101 G01N 27/38 361 G01N 33/18 106

Claims (1)

(57) [Claims] An apparatus having a disk-shaped ultrasonic vibrator and a vibrating plate fixed to the vibrator, which is mounted on a measuring instrument used in a state of being immersed in water, An ultrasonic cleaning device for cleaning a portion located in a space narrower than the diameter of the vibrator in the above, wherein the surface of the vibrator on the side opposite to the surface fixed to the vibrator, An ultrasonic cleaning device, comprising: a cylindrical resonance portion having a diameter smaller than a diameter and having an outer diameter capable of being inserted into the space.