JPS6357199A - Abrasive jet nozzle - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an abrasive jet nozzle for cutting stone materials such as concrete and iron materials by discharging a pressurized fluid and an abrasive material from a nozzle opening.

[Conventional technology]

Conventionally, diamond blades have been used to cut concrete and other stones and iron materials in building demolition work, road construction, etc. However, these diamond blades suffer from severe blade wear and are uneconomical, as well as being noisy due to cutting. The problem was that this occurred.

Therefore, in recent years, a method of cutting using an ultra-high pressure water jet has been proposed and put into practical use as a more efficient cutting method. This involves discharging water at a high pressure of 1 to 3 tons from a tiny nozzle orifice, causing the water to travel straight at ultra-high speed, concentrating stress on one point, and using that energy to cut the object. It is an excellent method that does not apply any pressure, does not generate vibrations, does not cause cracks, etc., and can suppress noise. Recently, in order to further enhance the cutting ability of the ultra-high pressure water jet, an abrasive jet cutting method has been proposed in which an abrasive material such as fine garnet is mixed into the discharged water. A common type of abrasive jet nozzle used for this abrasive jet cutting is one shown in FIG. 5, for example. That is, in this nozzle, a high-pressure water flow path 1 is formed linearly in the direction of the center axis of the nozzle, and an abrasive material flow path 2 is formed concentrically outside this high-pressure water flow path 1. The abrasive is supplied from the abrasive supply port 3. A high-pressure water outlet 4 is opened at the tip side of the abrasive flow path 2, and the abrasive and water are mixed between the high-pressure water outlet 4 and the nozzle port 5, and the mixed water is discharged from the nozzle port 5. is discharged at high pressure. Note that 6 is an air inlet for blowing the abrasive material in the direction of the nozzle opening 5.

As shown in FIG. 6, which is an enlarged view of the vicinity of the nozzle opening 5 in FIG. The object is cut by colliding the abrasive material 7 against the object.

[Problem that the invention seeks to solve]

However, in the conventional abrasive jet nozzle, the abrasive material 7 is accelerated by the water discharged at high pressure in the internal space from the high-pressure water discharge port 4 to the nozzle port 5, and is rubbed against the inner wall surface of the flow path. Since it reaches the nozzle opening 5 while scraping off the inner wall surface, the inner wall surface in the area indicated by the dashed line A in FIG. 5 is considerably worn. Therefore, if this abrasive jet nozzle is used to continuously cut concrete materials, etc., the inner wall of the nozzle will wear out in a relatively short period of time, and wear debris will clog the nozzle opening 5, making the nozzle unusable. The nozzle had to be replaced, which was a big problem. Furthermore, accelerating the abrasive material 7 by mixing it with the water stream is a prerequisite for improving cutting performance, but normally the diameter of the water stream to be discharged is less than l u+ and the flow velocity is 500 m/sec. As above, the water flow is more like a solid than a liquid, so the abrasive material 7
The reality is that more of the water is thrown away than mixed into the water flow. Therefore, the flung abrasive material 7 hits the target object at a low speed and falls without contributing to cutting, and the problem is that the effect of improving cutting performance cannot be obtained unless a large amount of abrasive material 7 is supplied. Met. This is a major cost problem since the abrasive material 7 is relatively expensive. Furthermore, since the abrasive material 7 accelerated by the water flow is discharged from the outside of the water flow,
The abrasive material 7 inevitably spreads toward the outer periphery, and the diameter tends to become larger than the diameter of the nozzle opening 5 (see Fig. 6).
It was also said that there was room for improvement because the cutting point was larger than the nozzle opening 5 and the cut surface was not very sharp.

This invention was made in view of the above circumstances, and the nozzle inner wall is not worn by the abrasive material 7, the nozzle life is long, the cutting performance is excellent, and a small amount of the abrasive material 7 can be supplied.
The object of the present invention is to provide an excellent abrasive jet nozzle that can form a sharp cut surface.

[Means for solving problems]

To achieve the above object, the abrasive jet nozzle of the present invention includes a nozzle opening, a pressurized fluid outlet and an abrasive outlet positioned and formed within the nozzle opening, and a pressurized fluid outlet connected to the pressurized fluid outlet. and an abrasive flow path connected to the abrasive outlet, the pressurized fluid outlet being arranged to surround the abrasive outlet; Further, the pressurized fluid flow path and the abrasive material flow path are formed independently.

That is, the abrasive jet nozzle of this invention is
The pressurized fluid flow path and the abrasive material flow path are formed independently of each other, and the tips of both flow paths extend into the nozzle opening, so both fluids are in contact with each other until they are discharged from the nozzle opening. There's nothing to do. Therefore, the abrasive material is not accelerated by the pressurized fluid in the nozzle and rubbed against the inner wall surface of the nozzle, thereby preventing wear of the inner wall. Further, since the pressurized fluid discharge port is arranged to surround the abrasive material discharge port, the pressurized fluid surrounds the abrasive material and is discharged in a cylindrical shape. The pressurized fluid discharged at this time is extremely high-velocity, and forms a so-called cylindrical wall around the abrasive discharge port, bringing the cavity surrounded by the wall into a low-pressure state close to vacuum. Therefore, the abrasive material is sucked into the low-pressure cavity and moves while accelerating, and all of the abrasive material that is discharged is not diffused beyond the cylindrical wall formed by the pressurized fluid. It is efficiently used for cutting in a naturally accelerated state. As a result, it exhibits excellent cutting performance with a much smaller amount of abrasive supplied compared to the conventional method. This is a major feature of this invention.

Next, the present invention will be explained in detail based on examples.

〔Example〕

FIG. 1 shows a longitudinal section of an embodiment of the invention.

That is, this abrasive jet nozzle includes an inner cylindrical body 11 having an abrasive flow path 10 linear in the nozzle central axis direction, an outer cylindrical body 12 that is fitted onto the inner cylindrical body 11, and an outer cylindrical body 12 that is fitted onto the inner cylindrical body 11. A cap 13 that fits onto the cylindrical body 12 is provided.

At the fitting portion between the outer cylinder 12 and the inner cylinder 11, the inner diameter of the outer cylinder 12 is larger than the outer diameter of the inner cylinder 11, and the inner peripheral wall of the outer cylinder 12 is larger than the outer diameter of the inner cylinder 11. Above inner cylinder body 1
A gap between the outer circumferential wall of the pressurized fluid and the outer circumferential wall of the pressurized fluid is formed in a flow path 14 for the pressurized fluid. The cap 13 has a nozzle port 15 in its center, and the tip side of the flow path 10 for the abrasive material extends in a small diameter state within the nozzle port 15, and the flow path for the pressurized fluid is formed on the outer periphery of the nozzle port 15. 14 tip narrow diameter portions are formed in position. The tip of the abrasive channel 10 serves as an abrasive outlet 16, and the tip of the pressurized fluid channel 14 serves as a pressurized fluid outlet 17. That is, in the nozzle port 15, the pressurized fluid discharge ports 16 are arranged in a ring shape with the abrasive material discharge port 16 at the center and concentrically surrounding the abrasive material discharge port 16. In addition, on the inner peripheral surface of the nozzle opening 15,
A diamond layer 18 is formed to protect the inner wall and maintain the diameter accuracy of the nozzle opening 15.

The supply of abrasive to the abrasive jet nozzle is as follows:
Narrow diameter portion 11a of the inner cylinder 11 protruding from the outer cylinder 12
This is carried out by connecting an abrasive supply hose (not shown) that communicates with an abrasive tank (not shown) and feeding the abrasive material at low pressure using water or air flow. The type of abrasive to be supplied is not limited at all, but garnet, silica sand, etc. are common. The grain size of garnet is preferably about #36 to #60, and the grain size of silica sand is preferably about #4 to #6.

On the other hand, as shown in FIG. 2, which is a sectional view taken along the line AA' in FIG. A pressurized fluid supply hose (not shown) is connected to the provided supply hole 19, and the fluid is supplied from an ultra-high pressure pump (not shown) via the hose. Water is usually used as the fluid to be supplied.

Cutting of concrete, etc. using the abrasive jet nozzle is carried out in accordance with a normal method. However, in the abrasive jet nozzle, unlike conventional nozzles, the abrasive discharge port 16 discharges pressurized fluid. The abrasive material is surrounded by the outlet 17, and the abrasive material is entrained in the momentum of the fluid discharged from the pressurized fluid discharge port 17 at an extremely high speed, and is discharged while being surrounded by the fluid, so that the entire abrasive material is significantly damaged. It is accelerated and discharged. Therefore, it is possible to demonstrate a dramatic cutting ability compared to the conventional method. Specifically, when this abrasive jet nozzle was used to cut concrete under the same conditions as before, it exhibited cutting performance that was approximately twice that of the conventional product (see Figure 5). Moreover, at this time, the abrasive material is discharged while being surrounded by the cylindrical discharged pressurized fluid, so it is sucked into the cavity formed by the cylindrical wall of the discharged pressurized fluid and is discharged while accelerating. (FIG. 3), unlike the conventional case, the cutting point does not spread outward and the cutting point does not become larger than the nozzle opening 15. Therefore, a sharper cut surface than ever before can be obtained. Also,
Since the abrasive material 7 reaches the surface of the target object (concrete, etc.) while being surrounded by the pressurized fluid, there is no wasted abrasive material 7 that falls without contributing to cutting as in the conventional method, and the abrasive material 7 The discharge amount can be set much smaller than before, making it economical. Furthermore, in the abrasive jet nozzle, the flow path 14 for the pressurized fluid and the flow path 10 for the abrasive material 7 are formed independently of each other up to the nozzle opening 15, so that the abrasive jet nozzle cannot be used for polishing as in the conventional method. The material 7 does not collide with the inner wall of the nozzle port 15 while being accelerated by the pressurized fluid. Therefore, 1. The inner wall of the nozzle port 15 is not worn away by the abrasive material 7. As a result, the nozzle life is extremely long.

In the above embodiment, the abrasive jet nozzle is formed from the inner cylinder 11, the outer cylinder 12, and the cap 13, but the cap 13 does not need to be made separately from the outer cylinder 12. do not have. That is, in the above embodiment, nozzle port 1
Since it is necessary to form a diamond layer 18 to protect the inner wall of the peripheral portion of the outer cylinder 12, the cap 13 is made an independent component.
The cap 13 is not required if such a protective layer is not provided. Note that a ceramic layer or a cemented carbide layer may be used as the protective layer.

Further, in the above embodiment, the pressurized fluid outlet 17 is arranged in the nozzle opening 15 in a ring shape concentrically surrounding the abrasive outlet 16, but as shown in FIG. The pressurized fluid outlet 17 has a plurality of small holes,
The plurality of small holes may be arranged concentrically surrounding the abrasive discharge port 16.

〔Effect of the invention〕

As described above, in the abrasive jet nozzle of the present invention, the flow path for the pressurized fluid and the flow path for the abrasive material are formed independently of each other up to the nozzle opening, so that the abrasive jet nozzle is not discharged from the nozzle opening. The two fluids do not come into contact until Therefore, the abrasive material is not accelerated by the pressurized fluid in the nozzle and rubbed against the inner wall surface of the nozzle, thereby causing wear on the inner wall, and the life of the nozzle is dramatically extended compared to the conventional one. Further, pressurized fluid surrounds the abrasive material and is discharged in a cylindrical shape. The pressurized fluid discharged at this time is extremely high speed,
A so-called cylindrical wall is formed around the abrasive discharge port, and the cavity surrounded by the wall is brought into a low pressure state close to vacuum. Therefore, the abrasive material is sucked into the low-pressure cavity and moves while accelerating, and all of the abrasive material that is discharged is not diffused beyond the cylindrical wall formed by the pressurized fluid. It is used for efficient cutting in a naturally accelerated state.As a result, it exhibits excellent cutting performance with a smaller amount of abrasive supply compared to conventional methods.This results in a significant reduction in costs. It is.

Moreover, as mentioned above, since the abrasive material is discharged surrounded by the cylindrical wall of the pressurized fluid, the abrasive material does not spread, and the cutting point does not spread beyond the diameter of the nozzle opening, resulting in a sharp cut surface. This is also an advantage.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line A-A', and FIG. 3 is an explanation explaining the discharge state of the abrasive material and pressurized fluid of the above embodiment. 4 is a partial perspective view showing the vicinity of the nozzle opening of another embodiment of the present invention, FIG. 5 is a vertical sectional view showing the conventional example, and FIG. 6 is the abrasive and water of the conventional example. It is an explanatory view explaining a discharge state. 7... Abrasive material 10... Abrasive material flow path 14...
Pressurized fluid flow path 15... Nozzle port 16... Abrasive material discharge port 17... Pressurized fluid discharge port 1 Fig. 2 Fig. 4 Fig. 5 Fig. 6

Claims (1)

[Claims] (1) A nozzle port, a pressurized fluid discharge port and an abrasive material discharge port positioned and formed within the nozzle port, a pressurized fluid flow path connected to the pressurized fluid discharge port, and the abrasive material discharge port. an abrasive flow path connected to the abrasive material flow path, the pressurized fluid outlet is arranged to surround the abrasive material outlet, and the pressurized fluid flow path and the abrasive flow path are connected to the abrasive flow path. An abrasive jet nozzle characterized in that passages are formed independently of each other.