JPH06238198A - Water jet nozzle - Google Patents

Abstract

PURPOSE:To realize a property to concentrate cutting to an object, the uniformity of the cutting diameter on a cutting surface and the smoothness on the cutting surface and to enable high-performance cutting by hermetically closing the rear part of the Coanda slit of the Coanda spiral nozzle having a slope connecting the Coanda slit and an ejection port. CONSTITUTION:The rear part 9 of the Coanda slit 4 of the Coanda spiral nozzle 1 having the slope 5 connecting the annular Coanda slit 4 for high-pressure water supply forming Coanda slit spiral flow 10 and the ejection port 2 is hermetically closed. The peeling of the flow does not, therefore, arise and the destruction of the Coanda spiral flow 10 does not arise either even if the high- pressure water is supplied from a distributing chamber 6 via the Coanda slit along the slope of the Coanda spiral nozzle 1. Therefor, the decrease of the pressure inside the nozzle is prevented and the back flow is prevented. The ultra-high-velocity jet ejected therefrom has an excellent converging property and stability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water jet nozzle. More specifically, the present invention relates to a high performance water jet nozzle capable of forming a cutting surface having excellent cutting concentration and uniformity and low roughness.

[0002]

[Prior art and its problems] Traditionally, mining industry, construction industry,
BACKGROUND ART In medical treatment and the like, cutting, cutting and excavation using a water jet are carried out, and improvement and ingenuity of a nozzle device therefor are being advanced. However, in the case of this conventional water jet nozzle,
There are drawbacks that the concentration of the cutting portion is poor, the cutting hole is enlarged, and the cutting surface is rough. For this reason, when it is desired to make the cut portion have a uniform diameter and to make the cut surface smooth, a step of scraping off with a file or the like is required after cutting with a water jet, which is extremely inefficient.

These drawbacks have been caused by the divergence and instability of the water jet jet. Therefore, as a method for solving these drawbacks, a cutting method using high-pressure water containing a polymer has been proposed in place of the conventional high-pressure water. This method is derived from the physical consideration that the concentration and stability of the jet flow depend on the viscosity of the jet flow, and the higher the viscosity, the better the convergence and stability.

However, such a water jet containing a polymer has problems that it is troublesome to handle, the cost is very high, and it can be used only for a very limited purpose. Thus, in the past, the focus has been on improving the physical properties of jets in order to generate jets with high convergence and stability. Therefore, there was no idea to control the fluid from the structure of the water jet nozzle.

In view of such a situation, the inventor of the present invention has developed and proposed a new nozzle means itself. This means uses the Coanda spiral flow, which has been actively studied by the inventor for application to various application fields, as a principle method for water jet cutting.

That is, this Coanda spiral flow exhibits a so-called steeper velocity distribution in which the velocity difference between the axial direction of the fluid and its surroundings and the density difference are large, the axial flow is fast and the external flow is slow, and Has a characteristic that the turbulence shows a value of 0.09, which is half the value of 0.2 of the normal turbulence or less, and forms a stable state different from the normal turbulence. Moreover, there is a feature that a unique spiral flow is formed by combining the axial method vector and the radial direction vector.

Utilizing the fact that this Coanda spiral flow swirls while converging on the shaft and is a stable flow with little turbulence, it is possible to perform cutting, excavation, and cutting efficiently and with good performance. A water jet nozzle has been realized. FIG. 1 is a cross-sectional view of a water jet nozzle that the present inventor has already proposed.

For example, as shown in FIG. 1, for the Coanda spiral nozzle (1), the ejection port (2)
-Shaped Coanda slit (4) between the suction port and suction port (3)
A structure having an inclined surface (5) in the vicinity thereof and a high pressure water distribution chamber (6) can be shown as a typical example. In the Coanda spiral nozzle (1), water having a pressure higher than that of the pump (7) toward the jet outlet (2) through the annular Coanda slit (4) and the suction port (3) are also provided.
More water stream (8) is supplied.

The angle of the inclined surface (5) is, for example, 5 to 70 °.
By setting the degree to a certain degree, a spiral flow (10) is formed, and a strong negative pressure suction force is generated in the suction port (3), and as a result, water is guided and jetted by this negative pressure suction force. The water jet of the spiral flow (10) ejected from the Coanda spiral nozzle (1) has very little turbulence and collides with an object while converging on the shaft to cut it. In other words, the water jet ejected from the Coanda spiral nozzle (1) has excellent convergence and stability.

For this reason, the water jet nozzle for forming the Coanda spiral flow realizes high-concentration cutting by realizing the cutting concentration of the object, the uniformity of the cutting diameter on the cutting surface, and the smoothness on the cutting surface. It was possible and showed extremely excellent effectiveness over conventional methods. However, subsequent studies by the inventors have revealed that there is a point to be further improved in the case of this water jet nozzle using the Coanda spiral flow.

Generally, when the object is hard such as concrete or metal, the jet flow for cutting or cutting needs to be ultra-high speed. Therefore, the supply pressure of the water jet flow is 500 to 2000 kg / It must be a high pressure of about cm ² . In such a case, in the conventional Coanda spiral nozzle (1), the flow ejected from the annular Coanda slit (4) shown in FIG. 1 becomes super-high speed, and the flow separation occurs on the inclined surface (5), which causes suction. There is a problem in that a negative pressure suction force is not generated in the mouth (3), a backflow is generated from the suction opening (3), and the jet velocity ejected from the jet outlet (2) is rapidly reduced.

Therefore, in the conventional nozzle (1),
It was possible to form a jet with excellent convergence and stability, but it was not possible to obtain an ultrahigh-speed jet, and it was impossible to cut a hard object. The present invention has been made in order to eliminate the drawbacks as described above, and even if the supply pressure of the water jet is high, it forms an ultra-high-speed jet having excellent convergence and stability, It is an object of the present invention to provide a water jet nozzle that achieves high-performance cutting by achieving cutting concentration of an object, uniformity of cutting diameter on the cutting surface, and smoothness on the cutting surface.

[0013]

The present invention is to solve the above-mentioned problems by providing an annular Coanda slit for supplying high-pressure water that produces a Coanda spiral flow, and an inclined surface connecting the Coanda slit and the ejection port. In a Coanda spiral nozzle having the above, there is provided a water jet nozzle characterized in that a rear part of the Coanda slit is hermetically sealed. Furthermore, the present invention also provides a water jet nozzle provided with a check valve that is openable and closable for introducing cutting particles in the rear part of the Coanda slit.

[0014]

FIG. 2 is a sectional view illustrating the water jet nozzle of the present invention. For example, as illustrated in FIG. 2, the rear portion (9) of the Coanda slit (4) corresponding to the suction port (3) of the conventional nozzle is sealed. For this reason,
Even if high-pressure water is supplied from the distribution chamber (6) through the annular Coanda slit (4) along the inclined surface (5) of the Coanda spiral nozzle (1), flow separation does not occur. Even if the Coanda spiral flow is not destroyed, it is possible to prevent the pressure inside the nozzle from decreasing and prevent backflow.

Further, in the present invention, as illustrated in FIG. 3, a check valve (11) which can be opened and closed may be provided in the rear portion (9). When the check valve (11) is opened, a liquid mixed with cutting particles such as an abrasive (abrasive) is supplied at high pressure to prevent backflow and improve cutting efficiency. Examples will be shown below to describe the water jet nozzle of the present invention in more detail.

[0016]

EXAMPLES Examples Actually, using the Coanda spiral nozzle (1) having a diameter of 8 mm of the ejection port (2) shown in FIG.
At 0 cm, concrete with a thickness of 20 cm was cut. At this time, high-pressure water having a pressure of 2000 kg / cm ² and a flow rate of 4 l / min was supplied from the annular Coanda slit (4).

Further, a normal turbulent flow is generated for comparison.
Water jet cutting was attempted by mixing cutting particles with a conventional water jet nozzle. The water supply pressure and the outlet diameter were the same as in the case of the Coanda spiral nozzle. The result of this cutting was as shown in FIG. That is, when the Coanda spiral nozzle of the present invention is used (A), the concrete (12)
The cutting diameter of 5 mmφ is almost constant and is uniformly concentrated. On the other hand, when the conventional water jet nozzle is used (B), the cutting diameter of concrete is about 12 mm on the upper surface and then 4 cm. Up to the neighborhood, there was a tendency for shrinkage, with a minimum of about 5 mmφ, but after that there was a tendency for expansion, and under the concrete, it was about 20 mmφ
It had spread to.

Furthermore, comparing cutting surfaces, when the Coanda spiral nozzle of the present invention is used, the cutting surface is very smooth, but when using the conventional water jet nozzle, the cutting surface is Was very coarse. And the cutting time, in the case of this invention,
It was about 2/3 of the case of the turbulent flow nozzle. It can be seen that the ultra-high-speed jet flow ejected from the Coanda spiral nozzle of the present invention is converging and has little turbulence and is stable. On the other hand, it can be seen that the jet flow ejected from the conventional turbulent water jet nozzle diverges and the turbulence is extremely large and unstable.

For comparison, a similar attempt was made using the conventional Coanda spiral nozzle shown in FIG. 1, but backflow to the suction port (3) occurred, and the cutting had to be interrupted. However, when cutting and interruption were repeated to perform all cutting, the time was almost the same as that of the conventional turbulent flow nozzle. The concentration and uniformity of cutting were obtained as in the present invention. Cutting durability, stability, and efficiency were excellent with this invention.

[0020]

As is apparent from the above, the ultra-high-speed jet ejected from the Coanda spiral nozzle of the present invention has excellent convergence and stability, and as a result, the object is a hard body such as concrete or metal. Even if it is, the cutting concentration is excellent, the cutting diameter on the cutting surface does not spread, it is uniform, and the roughness of the cutting surface is low, and high-performance cutting is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional Coanda spiral water jet nozzle.

FIG. 2 is a sectional view of the water jet nozzle according to the present invention.

FIG. 3 is a sectional view of a water jet nozzle according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a cutting situation as an example.

[Explanation of symbols]

 1 Coanda spiral nozzle 2 Jet port 3 Suction port 4 Coanda slit 5 Sloping surface 6 Distribution chamber 7 Pump 8 Water flow 9 Rear part 10 Coanda spiral flow 11 Check valve 12 Concrete

Claims (2)

[Claims] 1. A Coanda spiral nozzle having an annular Coanda slit for supplying high-pressure water for generating a Coanda spiral flow and an inclined surface connecting the Coanda slit and the jet outlet, wherein a rear part of the Coanda slit is hermetically sealed. Water jet nozzle characterized by. 2. A Coanda spiral nozzle having an annular Coanda slit for supplying high-pressure water for generating a Coanda spiral flow and an inclined surface connecting the Coanda slit and the ejection port, for introducing cutting particles to the rear part of the Coanda slit. A water jet nozzle with a check valve that can be opened and closed.