JP2001164862A - Aerial cavitation jet generating nozzle, drilling machine with it, and drilling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aerial cavitation jet generating nozzle, a drilling device with it, and a drilling method increasing the destructing force per unit power and applicable to an execution section in a wide range by generating a stable aerial cavitation jet. SOLUTION: This drilling device is provided with a tapered high-pressure water jet nozzle injecting high-pressure water and a low-pressure water jet nozzle provided to surround the high-pressure water jet nozzle, formed with a water chamber in which the lower-pressure water from a low-pressure water inlet flows, and formed with a contraction section having a contracted passage area on the outlet side of the water chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airborne cavitation generating nozzle comprising a high-pressure water jet nozzle and a low-pressure water jet nozzle for generating a water jet containing cavitation in the air, and comprising the nozzle and The present invention relates to an aerial cavitation excavation machine and an excavation method for crushing objects to be destroyed such as rocks and concrete by the jetted water jet.

[0002]

2. Description of the Related Art Conventionally, in a drilling machine such as a tunnel drilling machine and various construction machines, a water jet (aerial water jet) is used for excavation, cutting, washing, etc., but such a water jet is a droplet. Collides with the material surface and utilizes the excavation effect of the impact pressure of the droplet collision.The excavation ability depends on the droplet volume and velocity, that is, the jet flow rate and the injection pressure. Increasing the droplet speed to obtain it has limitations on the apparatus, and increasing the flow rate leads to a large increase in the power used, and also consumes a large amount of water, so that there is a problem that the cost is high. I have.

In order to increase such a problem, that is, to increase the drilling capacity per unit of the water jet, a drilling method for crushing rocks or the like using a cavitation jet has been proposed and used in recent years.

[0004] In the invention of Japanese Patent Application Laid-Open No. 50-45366, a cylindrical resistor is installed in a nozzle, and cavitation is generated at a downstream end of the resistor in a low-pressure portion due to flow separation, and the cavitation bubbles are generated. Aerial water jets are included. In addition, Japanese Patent Publication No. 52-19363
In the invention of Japanese Patent Application Laid-Open No. 58-80036 and Japanese Patent Application Laid-Open No. 58-80036, cavitation is generated by simply jetting a water jet in water. Further, in Japanese Patent Application Laid-Open No. 2-30893, cavitation is generated by a magnetostrictive vibration method.

[0005]

However, the cavitation-generating excavating means in the prior art has the following problems. That is, JP-A-50-45
In No. 366, since cavitation bubbles are generated by the separation flow, the growth distance of the bubbles cannot be sufficiently large, and the bubbles collapse relatively quickly, and the object to be destroyed has an effect of destroying the object to be destroyed. The distance between the nozzle and the nozzle becomes short, and a large destructive force per unit power cannot be obtained.

In the inventions of Japanese Patent Publication No. 52-19363 and Japanese Patent Application Laid-Open No. 58-80036, when the invention is used for excavation of a tunnel, it is necessary to submerge a construction part. Is limited, and construction in a wide area is difficult. Furthermore, in the invention of Japanese Patent Application Laid-Open No. 2-30893, it is necessary that the cavitation bubble generation section always keeps a fixed position within several mm with the construction section such as a rock, and the accumulation density of the cavitation bubble group is increased. Is lower than the cavitation created by the

[0007] In view of the problems of the prior art, the present invention increases the destructive force per unit power by generating a cavitation jet in a stable atmosphere.
An object of the present invention is to provide an aerial cavitation jet generation nozzle applicable to a wide range of construction sections, an excavating machine having the same, and an excavating method.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a first aspect of the present invention, wherein a high-pressure water jet nozzle having a tapered shape for jetting high-pressure water is provided so as to surround the high-pressure water jet nozzle. A low-pressure water jet nozzle in which a water chamber through which low-pressure water flows from the low-pressure water inlet is formed, and a flow-reducing portion having a reduced passage area is formed on the outlet side of the water chamber; The present invention proposes an aerial cavitation jet generation nozzle characterized by having:

The invention according to claim 8 is an invention of a method in which the aerial cavitation jet generating nozzle according to the invention of claim 1 is applied to an excavation machine and used, and the excavation method for crushing a destructible object such as a rock. In, an aerial cavitation generation nozzle consisting of a high-pressure water jet nozzle that injects high-pressure water and a low-pressure water jet nozzle that ejects low-pressure water is attached to the end of the attachment for excavation, and the low-pressure water from the low-pressure water jet nozzle is Injecting simultaneously with the high-pressure water so as to surround the outside of the high-pressure water jet from the high-pressure water jet nozzle, generating cavitation in a shear layer formed between the high-pressure water jet and the low-pressure water jet, including the cavitation It is characterized by crushing objects to be destroyed by aerial cavitation jet.

The invention according to claim 7 is an invention of an excavating machine provided with the aerial cavitation generating nozzle according to the invention of claim 1, wherein the excavating machine for crushing an object to be destroyed such as a rock is provided with a high pressure water. A high-pressure water jet nozzle that jets
A flow reducing portion provided to surround the high-pressure water jet nozzle and having therein a water chamber through which low-pressure water flows from a low-pressure water inlet and having a reduced passage area on the outlet side of the water chamber; And a low-pressure water jet nozzle formed with an air cavitation generation nozzle.

According to this invention, the low-pressure water flowing from the low-pressure water inlet into the water chamber in the low-pressure water jet nozzle flows through the water chamber and reaches the contraction portion provided on the outlet side of the water chamber. The turbulence of the flow is suppressed in the contraction portion, and the high-pressure water is jetted into the air at the same time as the high-pressure water so as to enclose the high-pressure water jet jetted from the high-pressure water jet nozzle surrounded by the water chamber. At the time of the injection, since the high-pressure water jet nozzle is formed in a tapered shape, the flow of the low-pressure water jet flowing outside the nozzle is not disturbed. Injecting the high-pressure water jet into the low-pressure water jet injected into the jet, generating cavitation in a shear layer formed at a boundary where the high-pressure water jet and the low-pressure water jet come into contact with each other, the air including the cavitation A cavitation jet is generated.

When the aerial cavitation jet generated as described above is jetted onto a destructible object such as a rock, the stagnation pressure of the low-pressure water jet and the high-pressure water jet at the jet impingement surface on the destruction object. The cavitation bubbles collapse due to both the stagnation pressure and the surface of the object to be destroyed is excavated with a high impact pressure. Cracks are generated on the surface of the object to be destroyed by such high-pressure impact pressure, and the cracks are impacted and expanded by the impact pressure and the stagnation pressure of the low-pressure water jet and the high-pressure water jet that repeatedly act, This grows at a stretch and the object to be destroyed is crushed.

Therefore, according to the present invention, the high-pressure water jet is jetted into the rectified low-pressure water jet to generate cavitation in a shear layer formed between the high-pressure water jet and the low-pressure water jet. As it grows, a stable aerial cavitation jet can be generated. Further, since the object to be destroyed is crushed by the impact pressure of the aerial cavitation jet and the stagnation pressure of the low-pressure water jet and the high-pressure water jet, much larger breaking energy can be obtained as compared with the prior art.

According to a second aspect of the present invention, in the first aspect, a rectifying means for rectifying the low-pressure water introduced from the low-pressure water inlet is provided in the water chamber. According to this invention, the low-pressure water that has entered the water chamber of the low-pressure water jet nozzle has its turbulence rectified when flowing through the rectifying means, and is sent to the contraction section as low-pressure rectified water without turbulence, Here, it is further rectified and injected into the air. Therefore, according to this invention, by flowing the low-pressure water in series with the rectifying means and the contraction portion, a sufficiently rectified low-pressure water jet is obtained, and the action of forming the shear layer is promoted.

According to a third aspect of the present invention, in the first aspect, an ultrasonic vibrator is provided in the water chamber at a position upstream of a jet port of the high-pressure water jet nozzle. According to this invention, cavitation is generated by the shear layer formed at the boundary where the high-pressure water jet and the low-pressure water jet are in contact with each other. The bubble nuclei of the microbubbles increase, and the cavitation generating action is promoted.

According to a fourth aspect of the present invention, in the first aspect, the low-pressure water inlet is open in a direction in which a circumferential swirling flow is formed in the water chamber. And According to this invention, the low-pressure water is injected into the water chamber from the low-pressure water inlet, preferably in a tangential direction, so that the low-pressure water becomes a swirling flow having a swirling component in the water chamber. By causing high-pressure water to spout at the center of the water jet, the shear layer is formed,
Cavitation is generated. Therefore, according to the invention, since the swirling flow is formed by injecting the low-pressure water into the water chamber, preferably in a tangential direction, the formation of the shear layer and the generation of the cavitation are promoted, and the scattering of the low-pressure water is prevented. Thus, the cavitation jet reaches a longer distance.

According to a fifth aspect of the present invention, in the first aspect, a spiral guide mechanism (guide fin) for generating a swirling flow in the low-pressure water in the water chamber is provided in the water chamber. . According to this invention, since a spiral flow is formed in the low-pressure water in the water chamber by the spiral guide mechanism (guide fin), the formation of the shear layer and the generation of cavitation are promoted as in the invention of the fourth aspect. At the same time, scattering of low-pressure water is prevented, and the reach of the cavitation jet is extended.

According to a sixth aspect of the present invention, there is provided an aerial cavitation excavator having a nozzle for generating a water jet including cavitation in the air, and crushing a destructible object such as rock by the water jet ejected from the nozzle. A high-pressure water jet nozzle having a tapered shape for injecting high-pressure water, wherein the high-pressure water jet nozzle has a large-diameter flow passage formed with a large diameter, and a flow passage cross-section formed from the large-diameter flow passage. And a small-diameter flow path having a reduced diameter.

This invention relates to the structure of the high-pressure water jet nozzle. The high-pressure water jet nozzle has a large-diameter flow passage and a small-diameter flow passage whose cross-section is reduced stepwise from the large-diameter flow passage. With the combination of the flow path structure and the above, a separation flow occurs on the upstream side of the jet outlet of the high-pressure water jet nozzle, and the generation of bubble nuclei is promoted.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. It's just

FIG. 1 is a longitudinal sectional view showing a first embodiment of an air cavitation jet generating nozzle according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a second embodiment of the nozzle, and FIG.
Shows a third embodiment of the nozzle, (A) is a longitudinal sectional view,
(B) is a view on arrow Z of (A). FIG. 4 shows the fourth nozzle.
Examples are shown, (A) is a longitudinal sectional view, (B) is A of (A)
It is -A sectional drawing. FIG. 5 is a longitudinal sectional view showing an example of a high-pressure water jet nozzle, and FIG. 6 is a longitudinal sectional view of a high-pressure water jet nozzle according to another embodiment in which cavitation is further promoted. FIG. 7 is a configuration diagram of an experimental device for an air cavitation jet generation nozzle according to the present invention, and FIG. 8 is an example of a drilling device incorporating the air cavitation jet generation nozzle according to the present invention. FIG. 9 is a performance diagram of the aerial cavitation jet generation nozzle, and FIG. 10 is a comparison diagram of the performance of the high-pressure water jet nozzle shown in FIGS.

FIG. 1 shows a first embodiment of an aerial cavitation jet generating nozzle (hereinafter referred to as a nozzle) of the present invention.
In the figure, reference numeral 10 denotes a nozzle, which is configured as follows. 4 is a low-pressure water jet nozzle, 5 is a water chamber formed in the nozzle body 7, 1 is a low-pressure water inlet for introducing low-pressure water into the water chamber 5, and the low-pressure water inlet 1 is provided with the water A plurality (or one) may be provided in the circumferential direction on the upstream side of the chamber. Reference numeral 41 denotes a contraction portion formed at the outlet of the water chamber 5 of the low-pressure water jet nozzle 4, and the outlet of the water chamber 5 is a flow path narrowed smoothly by the contraction portion 41.

Reference numeral 2 denotes a tapered high-pressure water jet nozzle for jetting high-pressure water. The outer periphery of the nozzle is tapered, penetrates the center of the low-pressure water jet nozzle 4 in the vertical direction, and is surrounded by the water chamber 5. It is provided. Reference numeral 3 denotes a flow straightening plate provided in the water chamber 5, which has a large number of through holes and is installed so that the plate surface is in a direction perpendicular to the water flow.

In the example shown in FIG. 5, the high-pressure water jet nozzle 2 connects a large-diameter flow channel 2d formed in the main body 2a and a jet flow channel 2h with a conical flow channel 2c. On the other hand, in another embodiment in which this is further improved, as shown in FIG. 6, a large-diameter flow path 2e is provided upstream of a main body 2a having a tapered outer periphery, and a large-diameter flow passage 2e is provided at an outlet side. Each of the small-diameter ejection passages 2f is formed, and the large-diameter passage 2e and the ejection passage 2f are connected to each other by a step 2g constituting a cavitator.

In the nozzle 10 having such a configuration,
The low-pressure water (for example, a pressure of 4.5 kg / cm ² ) which flows into the water chamber 5 from the low-pressure water inlet 1 of the low-pressure water jet nozzle 4 when flowing through the straightening plate 3 provided in the water chamber 5 The turbulence is rectified, and the turbulence is sent to the contraction part 41 as a low-pressure water jet without turbulence, where the turbulence is further rectified and injected into the air. In this case, by flowing the low-pressure water through the straightening plate 3 and the contraction portion 41 in series, a sufficiently-rectified low-pressure water jet can be obtained.

On the other hand, from the high-pressure water jet nozzle 2 surrounded by the water chamber 5, high-pressure water (for example, a pressure of 700 to 1200 k
g / cm ² ) is injected into the air simultaneously with the low-pressure water jet so as to be wrapped in the low-pressure water jet. At the time of such injection, since the high-pressure water jet nozzle 2 is formed in a tapered shape, the flow of the low-pressure water jet flowing outside the nozzle is not disturbed. The high-pressure water jet nozzle 2 has a large-diameter flow passage 2e and a small-diameter jet flow passage whose flow path cross section is reduced stepwise from the large-diameter flow passage 2e by a step 2g. By adopting a flow path structure combining 2f and
Separation flow occurs on the upstream side of the jet outlet of the high-pressure water jet nozzle 2, and the generation of bubble nuclei in the high-pressure water jet is promoted.
FIG. 10 shows a comparison of the amount of erosion between the conical nozzle shown in the example of FIG. 5 and the further improved cylindrical nozzle shown in FIG. 6 when a cavitation jet is jetted on a metal material.

Thus, the flow is sufficiently rectified and the contraction portion 4
As described above, the high-pressure water jet 51 in which the generation of bubble nuclei is promoted is jetted into the low-pressure water jet injected from the air into the air, and the boundary where the high-pressure water jet 51 comes into contact with the low-pressure water jet. Cavitation is generated by the shear layer formed in the cavitation, and the air cavitation jet 5 including the cavitation is formed.
0 is generated. Therefore, the high-pressure water jet 51 is injected into the rectified low-pressure water jet, and cavitation is generated and grown in a shear layer formed between the high-pressure water jet 51 and the low-pressure water jet. A cavitation jet 50 can be generated.

Then, the aerial cavitation jet 50 generated as described above is converted into a destructible object 70 such as a rock.
(FIG. 8), the cavitation bubbles collapse at both the stagnation pressure of the low-pressure water jet and the stagnation pressure of the high-pressure water jet at the jet impingement surface at the destructible object 70, Is excavated with high impact pressure. Cracks are generated on the surface of the object to be destroyed by such high-pressure impact pressure, and the cracks are impacted and expanded by the impact pressure and the stagnation pressure of the low-pressure water jet and the high-pressure water jet that repeatedly act, This grows at a stretch, and the object 70 is crushed. Therefore, the object 70 is crushed by the impact pressure of the aerial cavitation jet 50 and the stagnation pressure of the low-pressure water jet and the high-pressure water jet, so that a larger destruction energy can be obtained as compared with the related art.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, the high-pressure water jet nozzle 2 is provided in the water chamber 5 between the straightening plate 3 and the contraction portion 41 and the high-pressure water jet nozzle 2. The ultrasonic vibrator 21 is provided at an upstream portion of the nozzle. According to this embodiment, the cavitation generated by the shear layer formed at the boundary where the high-pressure water jet 51 and the low-pressure water jet come into contact with each other is vibrated by the ultrasonic vibrator 21 so that the cavitation is generated. The bubble nuclei of the microbubbles increase, and the cavitation generation action is promoted.
Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

In the third embodiment shown in FIG. 3, the low-pressure water inlet 1 (two in this example) in the first embodiment of FIG.
Are opened in the water chamber 5 in a tangential direction. Therefore,
According to this embodiment, by injecting low-pressure water tangentially from the low-pressure water inlets 1 and 1 into the water chamber 5, the low-pressure water becomes a swirl flow 32 having a swirl component in the water chamber 5,
By jetting the high-pressure water jet at the center of the low-pressure water jet that has become the swirling flow 32, a shear layer similar to that described above is formed, and cavitation is generated.

In this case, since a swirling flow is formed by injecting low-pressure water into the water chamber 5 in a tangential direction, formation of a shear layer and generation of cavitation are promoted. Also,
Spraying of low pressure water is prevented and cavitation jet 5
The reach of 0 is extended. The low-pressure water inlet 1 is
The direction is not limited to the tangential direction, but may be any direction in which the low-pressure water can form the swirl flow 32 having the swirl component in the water chamber 5. Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

In the fourth embodiment shown in FIG. 4, a guide fin 42 wound along the inner wall surface of the water chamber 5 is provided in the water chamber 5 of the low-pressure water jet nozzle 4. Thus, a swirling flow is generated in the low-pressure water. Therefore, in this embodiment, since a spiral flow is formed in the low-pressure water in the water chamber 5 by the spiral guide fins 42, the formation of a shear layer and the generation of cavitation are promoted as in the fourth embodiment. At the same time, scattering of low-pressure water is prevented, and the reach of the cavitation jet is extended. Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

In the third and fourth embodiments, the first
A rectifying plate 3 as in the second to second embodiments may be provided.

FIG. 7 shows a nozzle 1 according to the first to fourth embodiments.
It is a block diagram of the excavation experiment apparatus using 0. In FIG. 7, 11 is a water tank, 12 is an inner tank installed in the water tank 11, and the cavitation jet 50 is provided in the inner tank 12.
The nozzle 10 is attached so as to inject water. 13 is a low pressure pump, 16 is a high pressure pump, 17 is an underground pit, and 18 is a drain port.

In this excavation experiment apparatus, an excavation experiment is performed by using the low-pressure pump 13
While sending low-pressure water through 4, high-pressure water is sent from a high-pressure pump 16 through a high-pressure pipe 15, and the cavitation jet 50 is blown from the nozzle 10 to a destruction target 70 placed at the bottom of the inner tank 12, This was done by crushing. FIG. 9 shows a measurement result of the excavation speed when using granite and hard sandstone as the object 70 to be destroyed by such an excavation experiment apparatus.

FIG. 8 shows an example of a tunnel excavator 200 to which the nozzle 10 is attached as an attachment. In FIG. 8, the tunnel excavator 200 is mounted on a crawler type traveling device 111 via a turning device 112. , Upper revolving unit 113, high pressure pump 119 and low pressure pump 12
0 is installed in the pump chamber 121 and the plurality of movable booms 11
4, a boom cylinder 115 for driving the movable boom 114, the nozzle 10 according to the present invention attached to the tip of the movable boom 114, an attachment cylinder 116 for driving the nozzle 10, a high pressure water, a low pressure It comprises a hose 118 for supplying water to the nozzle 10 and the like.

129 is a water tank, 125 is the water tank 1
A hose connecting the high pressure pump 119 and the low pressure pump 120 to the hose 29, and a filter 128 are provided. 130 is a hose for recovering the jet water and the waste, which is connected to a jet water and waste collecting device (not shown).

The tunnel excavator 200 having the above configuration
Therefore, when excavating the pit which is the destructible object 70,
By moving the traveling device 111, the boom cylinder 115
Then, the attachment cylinder 116 is driven to position the nozzle 10 at the excavation position. Then, the high pressure pump 1
The cavitation jet 50 is ejected from the tip of the nozzle 10 by driving the 19 and the low-pressure pump 120 to excavate the object 70 to be destroyed. The excavated rocks and the like are scraped together with the jet water, and are recovered by the recovery device by a recovery hose 130.

Therefore, according to this embodiment, in the tunnel excavator 200, the nozzle 10 according to the first to fourth embodiments is used, and the cavitation jet 50 from the nozzle 10 is applied to the pit which is the object 70 to be destroyed. Since it is blown and crushed, it is possible to excavate the excavation surface in the predetermined area reliably and without large vibration without damaging other portions of the pit wall. In addition, the excavation reaction force is smaller than that of a mechanical cutter or the like, and wear is not generated due to mechanical friction.

Further, according to this embodiment, by providing a recovery device for recovering the jet water and the waste, the waste generated by the excavation can be efficiently and automatically discharged to the ground or to the outside. The performance is improved.

[0041]

As described above, according to the present invention, a tapered high-pressure water jet nozzle for jetting high-pressure water, and a high-pressure water jet nozzle are provided so as to surround the high-pressure water jet nozzle. A water chamber through which water flows is formed, and an aerial cavitation jet generation nozzle including a low-pressure water jet nozzle formed with a contraction portion having a reduced passage area on the outlet side of the water chamber is provided. Therefore, by injecting the high-pressure water jet into the rectified low-pressure water jet and generating and growing cavitation in a shear layer formed between the high-pressure water jet and the low-pressure water jet, a stable air flow is obtained. A cavitation jet can be generated. Further, since the high-pressure water jet nozzle is formed in a tapered shape, the flow of the low-pressure water jet flowing outside the nozzle is not disturbed.

The object to be destroyed is crushed by the impact pressure of the aerial cavitation jet and the stagnation pressure of the low-pressure water jet and the high-pressure water jet. The destructive power of is increased. Furthermore, since a stable aerial cavitation jet can be generated, it can be applied to a wide range of pits without damaging a portion other than the target portion to be destroyed.

According to a second aspect of the present invention, the low-pressure water is caused to flow in series between the rectifying means and the contraction section,
A well-rectified low-pressure water jet is obtained, and the action of forming a shear layer is promoted.

According to the third aspect of the present invention, by vibrating the water chamber with the ultrasonic vibrator, the number of bubble nuclei of microbubbles serving as a basis for cavitation increases, and the cavitation generating action is promoted. You.

According to the present invention, the swirling flow is formed by injecting low-pressure water into the water chamber, preferably in a tangential direction, so that the formation of a shear layer and the generation of cavitation are promoted. In addition, scattering of low-pressure water is prevented, and the reach of the cavitation jet is extended.

According to the fifth aspect of the present invention, a swirling flow is formed in the low-pressure water in the water chamber by the spiral guide mechanism, so that the shear layer is formed and the cavitation is formed in the same manner as in the fourth aspect of the invention. Is promoted, scattering of low-pressure water is prevented, and the cavitation jet can be extended.

According to a sixth aspect of the present invention, the flow path in the high-pressure water jet nozzle has a flow path structure in which a large diameter flow path and a small diameter flow path whose flow path cross section is reduced stepwise are combined. As a result, a separation flow occurs on the upstream side of the jet outlet of the high-pressure water jet nozzle, and the generation of cavitation bubble nuclei is promoted.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first example of an air cavitation jet generation nozzle according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the nozzle.

3A and 3B show a third embodiment of a nozzle, in which FIG. 3A is a longitudinal sectional view, and FIG.

4A and 4B show a fourth embodiment of a nozzle, wherein FIG. 4A is a longitudinal sectional view, and FIG. 4B is a sectional view taken along line AA of FIG.

FIG. 5 is a longitudinal sectional view showing an example of a high-pressure water jet nozzle according to the present invention.

FIG. 6 is a longitudinal sectional view showing another embodiment of the high-pressure water jet nozzle according to the present invention.

FIG. 7 is a configuration diagram of an experimental device of the air cavitation jet generation nozzle according to the present invention.

FIG. 8 is a side view of a tunnel excavator incorporating the aerial cavitation jet generation nozzle according to the present invention.

FIG. 9 is a performance diagram of the tunnel excavator.

FIG. 10 is a comparative diagram of the performance of the high-pressure water jet nozzle shown in FIGS. 5 and 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low-pressure water inlet 2 High-pressure water jet nozzle 2g Step part 3 Rectifier plate 4 Low-pressure water jet nozzle 5 Water chamber 7 Nozzle body 10 Nozzle 21 Ultrasonic vibrator 32 Swirling flow 41 Contraction part 42 Guide fin 50 Cavitation jet 200 Tunnel excavator

Continued on the front page. (72) Inventor Takayoshi Yamauchi 1-1-1, Wadazakicho, Hyogo-ku, Kobe-shi Inside the Kobe Shipyard, Mitsubishi Heavy Industries Co., Ltd. (72) Inventor Hideyuki Sakata 2-1-1, Araimachi, Takarai City, Hyogo Prefecture No. 1 F term in Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (Reference) 2D029 DB03 2D054 AC20 BA28 BB08 DA12

Claims (8)

[Claims] 1. A high-pressure water jet nozzle having a tapered shape for jetting high-pressure water, and provided so as to surround the high-pressure water jet nozzle.
A water chamber through which low-pressure water flows from the low-pressure water inlet is formed, and a low-pressure water jet nozzle having a flow-reducing portion with a reduced passage area is formed on the outlet side of the water chamber. An aerial cavitation jet generation nozzle characterized by the following. 2. The aerial cavitation jet generation nozzle according to claim 1, wherein a rectifying means for rectifying the low-pressure water introduced from the low-pressure water inlet is provided in the water chamber. 3. The aerial cavitation jet generation nozzle according to claim 1, wherein an ultrasonic vibrator is provided in the water chamber at a position upstream of a jet port of the high-pressure water jet nozzle. 4. The air cavitation jet generation nozzle according to claim 1, wherein the low-pressure water inlet is opened in a direction in which a circumferential swirling flow is formed in the water chamber. 5. The air cavitation jet generation nozzle according to claim 1, wherein a spiral guide mechanism for generating a swirling flow in the low-pressure water in the water chamber is provided in the water chamber. 6. The high pressure water jet nozzle, wherein a flow path thereof is
6. The aerial system according to claim 1, wherein the large-diameter flow path has a large diameter, and the small-diameter flow path has a cross section reduced in a stepped manner from the large-diameter flow path. Cavitation jet generation nozzle. 7. An excavating machine for crushing an object to be destroyed such as a rock, a high-pressure water jet nozzle for jetting high-pressure water, and a low-pressure water jet nozzle provided to surround the high-pressure water jet nozzle. A water chamber through which water flows is formed, and an aerial cavitation jet generation nozzle having a low-pressure water jet nozzle formed with a contraction portion having a reduced passage area on the outlet side of the water chamber is provided. A drilling machine characterized by the following. 8. An excavation method for crushing an object to be destroyed such as a rock, wherein an aerial cavitation generating nozzle including a high-pressure water jet nozzle for jetting high-pressure water and a low-pressure water jet nozzle for jetting low-pressure water is provided with an excavation attachment. At the end, the low-pressure water jet from the low-pressure water jet nozzle is jetted simultaneously with the high-pressure water so as to surround the outside of the high-pressure water jet from the high-pressure water jet nozzle, and between the high-pressure water jet and the low-pressure water jet. A method for excavating an aerial cavitation jet, wherein cavitation is generated by a shear layer formed in the cavitation, and an object to be destroyed is crushed by an aerial cavitation jet including the cavitation.