[Technical Field]
5 [0001]
The present invention relates to an ultrasonic treatment method and an ultrasonic
treatment apparatus.
[Background Art]
[0002]
10 Generally, in a manufacturing process of various types of metal objects such as
steel plates and steel pipes, a cleaning treatment method is widely used to remove dirt,
scales, and the like on a surface of the metal object by immersing the metal object in a
cleaning tank that contains chemicals (for example, alkaline degreasing agents, surfaceactive agents, sulfuric acid solutions, or other chemicals), rinses, and so on. Examples of
15 cleaning treatment apparatuses performing such cleaning treatment methods include, for
example, a treatment apparatus using high-pressure airflow injection nozzles and an
ultrasonic treatment apparatus using ultrasonic waves.
[0003]
To improve propagativity and uniformity of ultrasonic waves in various surface
20 treatments, including cleaning treatments for large materials such as steel plates and steel
pipes, ultrasonic waves are applied while moving a transducer as disclosed in Patent
Document 1 below, or an ultrasonic wave reflection member is installed for a treatment
tank as disclosed in Patent Document 2 below.
[Prior Art Document]
25 [Patent Document]
[0004]
Page 1 of 44
Patent Document 1: Japanese Laid-open Patent Publication No. H9-143767
Patent Document 2: International Publication Pamphlet No. WO 2018/169050
[Disclosure of the Invention]
[Problems to Be Solved by the Invention]
5 [0005]
It is considered that a plurality of treatment objects are grouped to form an
aggregate, and treatment is applied to this aggregate to further improve efficiency of
surface treatment. In this case, a degree of application of ultrasonic waves to the
treatment object located inside the aggregate is considered to be lower than that to the
10 treatment object located on an outer edge portion of the aggregate. Therefore, even if the
technologies disclosed in Patent Documents 1 and 2 above are used, the degrees of surface
treatment may differ between the treatment object located inside the aggregate and the
treatment object located on the outer edge portion of the aggregate.
[0006]
15 The present invention was made in view of the above problems, and an object
thereof is to provide an ultrasonic treatment apparatus and an ultrasonic treatment method,
which, when applying surface treatment to an aggregate made up of a plurality of treatment
objects, can more reliably propagate ultrasonic waves to the plurality of treatment objects
to achieve greater uniformity in the surface treatment.
20 [Means for Solving the Problems]
[0007]
To solve the above problems, the inventors have made a careful study and have
come up with the idea of providing a reflection member that reflects ultrasonic waves
inside the aggregate made up of the plurality of treatment objects and bringing the
25 reflection member and some treatment objects into contact while maintaining an
appropriate gap therebetween. Based on this conception, the inventors further
Page 2 of 44
investigated conditions for bringing the reflection member into contact with the treatment
objects while maintaining the appropriate gap therebetween.
The summary of the present invention completed based on such findings is as
follows.
5 [0008]
(1) An ultrasonic treatment method including: performing a surface treatment while
applying ultrasonic waves to a plurality of treatment objects under a state where a
treatment liquid is filled in a treatment tank, which has a long axis with almost identical
cross-sectional shapes and is provided with an ultrasonic application mechanism, and the
10 plurality of treatment objects extending in a longitudinal direction are immersed in the
treatment liquid, wherein each of the treatment objects is arranged to be in contact each
other with one or more other treatment objects at least at two points, one or a plurality of
hollow reflection vibrators extending in the longitudinal direction are arranged inside an
aggregate of the treatment objects in the treatment tank in a state immersed in the treatment
15 liquid to be away from an inner wall of the treatment tank, each of the reflection vibrators
is arranged to be in contact with other treatment objects at least at two points, when a
maximum value of an outer diameter of the treatment object in a cross-section
perpendicular to the longitudinal direction is set as Ds, and a maximum value of an outer
diameter of the reflection vibrator in a cross-section perpendicular to the longitudinal
20 direction is set as Dr, an outer diameter ratio Dr/Ds is 0.2 to 6.0, a specific acoustic
impedance Zr of the reflection vibrator is 1 × 107
to 2 × 108
kg‧m-2‧sec-1, and a hollow
portion of the reflection vibrator is filled with a liquid or gas having a specific acoustic
impedance Zi different from the specific acoustic impedance Zr.
(2) The ultrasonic treatment method according to (1), wherein the hollow portion of
25 the reflection vibrator is filled with gas having the specific acoustic impedance ratio Zi/Zr
of 1 × 10-3 or less.
Page 3 of 44
(3) The ultrasonic treatment method according to (2), wherein a thickness tr of the
Page 4 of 44
reflection vibrator is 0.2 to 3.0 mm.
(4) The ultrasonic treatment method according to (1), wherein the treatment liquid has
a dissolved gas content of 80% or more of a saturated dissolved gas content, and the
hollow portion of the reflection vibrator is filled with a liquid having the dissolved gas
5 content of less than 50% of the saturated dissolved gas content.
(5) The ultrasonic treatment method according to (1), wherein the hollow portion of
the reflection vibrator is filled with the treatment liquid.
(6) The ultrasonic treatment method according to (4) or (5), wherein the thickness tr
of the reflection vibrator is 3.0 to 20.0 mm.
10 (7) The ultrasonic treatment method according to any one of (1) to (6), wherein when
a length of the treatment object in the longitudinal direction is set as Ls and a length of the
reflection vibrator in the longitudinal direction is set as Lr, a length ratio Lr/Ls satisfies a
relationship of 0.7 ≤ Lr/ Ls ≤ 3.0.
(8) The ultrasonic treatment method according to any one of (1) to (7), wherein an
15 outer surface of the reflection vibrator is provided with a flange portion.
(9) The ultrasonic treatment method according to (8), wherein when a cross-sectional
size of the reflection vibrator at a portion provided with the flange portion is set as Df, a
ratio Df/Dr of the cross-sectional sizes satisfies a relationship of 1.1 ≤ Df/Dr ≤ 3.0.
(10) The ultrasonic treatment method according to (8) or (9), wherein the flange
20 portion has a modulus of rigidity G of 15 to 250 GPa.
(11) The ultrasonic treatment method according to any one of (8) to (10), wherein a
thickness tf of the flange portion is 2.0 to 10.0 times the thickness tr of the reflection
vibrator.
(12) The ultrasonic treatment method according to any one of (8) to (11), wherein the
25 flange portion is provided to be in contact with the treatment object at least at one point
within a range of 5 m in length of the treatment object along the longitudinal direction of
Page 5 of 44
the treatment object.
(13) An ultrasonic treatment apparatus including: a treatment tank that has a long axis
with identical cross-sectional shapes and contains a plurality of treatment objects extending
in a longitudinal direction and a treatment liquid immersing the treatment objects; and an
5 ultrasonic application mechanism that applies ultrasonic waves to the treatment liquid,
wherein each of the treatment objects is arranged to be in contact each other with one or
more other treatment objects at least at two points, one or a plurality of hollow reflection
vibrators extending in the longitudinal direction are arranged inside an aggregate of the
treatment objects in the treatment tank in a state immersed in the treatment liquid to be
10 away from an inner wall of the treatment tank, each of the reflection vibrators is arranged
to be in contact with other treatment objects at least at two points, when a maximum value
of an outer diameter of the treatment object in a cross-section perpendicular to the
longitudinal direction is set as Ds, and a maximum value of an outer diameter of the
reflection vibrator in a cross-section perpendicular to the longitudinal direction is set as Dr,
15 an outer diameter ratio Dr/Ds is 0.2 to 6.0, a specific acoustic impedance Zi of the
reflection vibrator is 1 × 107
to 2 × 108
kg‧m-2‧sec-1, and a hollow portion of the reflection
vibrator is filled with a liquid or gas having a specific acoustic impedance Zr different from
the specific acoustic impedance Zi.
[Effect of the Invention]
20 [0009]
As explained above, the present invention makes it possible to propagate
ultrasonic waves more reliably to a plurality of treatment objects and to achieve more
uniform surface treatment when applying surface treatment to an aggregate made up of the
plurality of treatment objects.
25 [Brief Description of the Drawings]
[0010]
Page 6 of 44
[FIG. 1A] FIG. 1A is an explanatory diagram schematically illustrating an
Page 7 of 44
example of an overall configuration of an ultrasonic treatment apparatus according to an
embodiment of the present invention.
[FIG. 1B] FIG. 1B is an explanatory diagram schematically illustrating an
example of the overall configuration of the ultrasonic treatment apparatus according to the
5 embodiment.
[FIG. 2A] FIG. 2A is an explanatory diagram to explain an ultrasonic application
mechanism in the ultrasonic treatment apparatus according to the embodiment.
[FIG. 2B] FIG. 2B is an explanatory diagram to explain the ultrasonic application
mechanism in the ultrasonic treatment apparatus according to the embodiment.
10 [FIG. 3] FIG. 3 is a schematic diagram to explain a reflection vibrator according
to the embodiment.
[FIG. 4] FIG. 4 is a schematic diagram to explain the reflection vibrator according
to the embodiment.
[FIG. 5] FIG. 5 is a schematic diagram to explain the reflection vibrator according
15 to the embodiment.
[FIG. 6] FIG. 6 is a schematic diagram to explain the reflection vibrator according
to the embodiment.
[FIG. 7] FIG. 7 is a schematic diagram to explain the reflection vibrator according
to the embodiment.