JPH0724736A - Nozzle assembly for sound deadening water jet - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a nozzle assembly for an abrasive water jet that suppresses noise and prevents scattering of abrasives. [Structure] Water for forming a water curtain on the outer periphery of the nozzle of the polishing fluid jet stream in which the abrasive is mixed and accelerated in the high-pressure high-speed jet stream, from the base end to the tip of the high-pressure jet water stream ejected from the nozzle. A curtain forming device was provided. By forming a water curtain on the entire outer circumference of the high-pressure jet water stream, noise is absorbed and cut off, and the kinetic energy of the abrasive colliding with the workpiece and being scattered is attenuated by the kinetic energy of the water curtain.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called "abrasive water jet", in which an abrasive is added to a jet stream of a high-speed fluid to enhance the cutting / grinding ability to cut metal, stone, glass, ceramics and the like. Relates to a sound deadening mechanism in a nozzle assembly of a processing apparatus.

[0002]

2. Description of the Related Art In processing by an abrasive water jet, a method of adding an abrasive to a high-pressure fluid jet stream is generally used as disclosed in Japanese Patent Publication No. 4,648,215. Further, Japanese Patent Laid-Open No. 63-501489 discloses that the conveyance for adding the abrasive to the high-pressure jet water stream is carried out by direct pressurization. It became possible to add it to the jet water stream, and it became possible to greatly improve its processing ability.

In such a processing method using a high-pressure jet water flow, the velocity of the jet flow ejected from the nozzle is several times as high as the speed of sound, and noise is large. Further, there is a drawback that the abrasive scatters in the vicinity and is dangerous, and it becomes difficult to collect the abrasive, and the utilization efficiency of the abrasive is lowered.

As a measure for preventing the scattering of the abrasive material to the periphery, a cup-shaped cover is provided at the lower end portion of the jet nozzle, or, as described in Japanese Patent Laid-Open No. 4-105900, It has been proposed to form a water curtain around the jet nozzle that surrounds the point on the work surface where the high-pressure jet water stream strikes.

However, even if the scattering of the abrasive can be prevented to some extent by these measures, the cover structure is largely damaged by the rebound, and even if it is called the water curtain disclosed in the above publication, It only suppresses the bounce of the high-pressure jet water stream at the reaching point, and has no function as a shield for sound deadening, so a sound deadening effect cannot be expected.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an effective means for blocking generated noise and preventing scattering of abrasives in a processing method using an abrasive water jet. .

[0007]

The present invention has achieved its object by forming a water curtain over the entire outer circumference of a high-pressure jet water stream ejected from an abrasive water jet nozzle.

In order to form a water curtain on the entire outer circumference of the jetted high-pressure jet water stream, a nozzle device is used in which a water curtain forming nozzle member having a slit-shaped opening is provided on the lower surface of the outer circumference of the mixing acceleration conduit portion at the tip of the nozzle. To do.

It is more preferable to further provide a hood for covering the outer peripheral portion of the nozzle having the water curtain with a predetermined gap.

[0010]

By forming a water curtain on the entire outer circumference of the high-pressure jet water stream, noise is absorbed and cut off and the surrounding noise is attenuated. Further, the kinetic energy of the abrasive colliding with the work piece and being scattered is attenuated by the kinetic energy of the water curtain.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example in which a water curtain forming nozzle member is provided on the outer periphery of a high pressure jet ejection nozzle in order to carry out the present invention.

In FIG. 1, a high-pressure jet water jet nozzle 10 has a conduit 2 and a nozzle opening 3 which are provided above the nozzle body 1 and which introduces a high-pressure fluid. 4 is provided with an abrasive mixing chamber 5 having an open end surface, in which the high-pressure jet water stream WJ to which the abrasive is added and mixed passes through a mixing acceleration conduit section 6,
It is ejected from the nozzle opening 7 at the lower end. Reference numeral 8 denotes a water curtain forming nozzle attached to the outer peripheral surface of the nozzle body 1 below the mixing acceleration conduit section 6.

FIG. 2 is a view showing a cross section taken along line AA shown in FIG. 1. As shown in FIG. 2, a water curtain forming nozzle 9 has a slit 9 for forming the water curtain all around the circumference. The water curtain WC formed and shown in FIG. 1 jets the high-pressure jet water stream JW jetted from the nozzle tip immediately after jetting in a form completely covering the entire circumference from the base end.

Using the apparatus shown in FIGS. 1 and 2, the surface of the SUS steel plate W was ground under the following conditions.

The water nozzle diameter is 0.33 mm,
The standoff distance is 2 mm, the projection angle is 45 °, the traverse speed is 2000 mm / min, and the water pressure is 3
The noise level and the amount of scattering of the abrasive when sprayed with # 120 cast iron grit as abrasive grains at 000 kg / cm ² .

When the relationship between the amount of pressurized water and the noise level was compared between the case where the water curtain was formed and the case where the water curtain was not formed, the noise amount was reduced to about half and the scattering amount of the abrasive was reduced to about 1/4.

[0017]

The present invention has the following effects.

(1) The generated noise can be effectively cut off without deteriorating the processability of the abrasive water jet.

(2) The amount of the abrasive scattered on the surface of the workpiece can be reduced, and the rate of recovery and reuse can be increased.

(3) Since the ground surface can be cleaned, it is easy to reinspect the flaw. Further, it is possible to send the material to the subsequent process without manually cleaning the surface of the workpiece.

(4) Minimize wear of the nozzle unit, nozzle driving device, auxiliary equipment and the like due to scattering and reflection of the abrasive, improve durability and contribute to reduction of processing cost.

[Brief description of drawings]

FIG. 1 shows an embodiment of a nozzle for an abrasive water jet of the present invention.

FIG. 2 shows a cross section of a mixing acceleration conduit section of the nozzle shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle body 2 High-pressure fluid introduction conduit 3 Nozzle opening 4 Abrasive pressurizing transfer pipe 5 Abrasive mixing chamber 6 Mixing acceleration conduit 7 Nozzle opening 8 Water curtain forming nozzle 9 Water curtain forming slit 10 High pressure jet water jet nozzle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inuma Osamu Inaoka 1-1 Tobahata-cho, Tobata-ku, Kitakyushu City, Fukuoka Prefecture Inside Nippon Steel Co., Ltd. Yawata Works (72) Inventor Tomoji Shimoda Tobata-ku, Kitakyushu City, Fukuoka Prefecture No. 1-1, Hibatacho, Nippon Steel Co., Ltd., Yawata Works (72) Inventor, Fujiya Nogami, No. 1, No. 1-1, Hibatamachi, Tobata-ku, Kitakyushu, Kitakyushu, Fukuoka, Japan (72) Inventor Hiroyuki Matsumura 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe City Kawasaki Heavy Industries Ltd. Kobe factory (72) Inventor Yoshikazu Ikemoto 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe City Kawasaki Seki Heavy Industries Kobe Inside the factory (72) Inventor Kyoji Tsujita 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe City Kawasaki Heavy Industries, Ltd. Kobe factory (72) Inventor Hidehisa Tanaka Higashikawa, Chuo-ku, Kobe 3-1, 1-1 Sakimachi Kawasaki Heavy Industries Ltd. Kobe factory

Claims (1)

[Claims] 1. A water curtain is formed on the outer circumference of a nozzle of a polishing fluid jet stream in which an abrasive is mixed and accelerated in a high-pressure high-speed jet stream, over the entire outer circumference from the base end to the tip of a high-pressure jet water stream ejected from the nozzle. Nozzle assembly for sound deadening water jets equipped with the water curtain forming device.