JPH10298614A - Method for measuring angle of inclination of conical water screen, and manufacturing equipment for metal powder using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and rapidly measure the angle of inclination of a conical water screen with respect to the axis while securing safety without requiring skill with respect to metal powder manufacturing equipment by a water atomization process and to facilitate the practice of the water atomization process capable of powder shape control by performing atomization at a small angle of inclination. SOLUTION: A laser-type distance measuring instrument 3 is disposed in the position at the rear of a circular water-atomizing nozzle 1 and on the cone axis, and laser beam irradiation is performed from inside of a conical water screen toward the top to measure the distance from the measuring instrument to the cone point. The distance from the measuring instrument to the plane including the nozzle is previously measured separately, and the distance from the plane including the nozzle to the cone point, that is, the height of the circular cone is determined. Subsequently, the angle of inclination is computed as a trigonometric function between the resultant value and a previously known nozzle radius.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conical water film formed by ejecting a water flow from a circular nozzle toward a center of a circle and inclined with respect to an axis passing through the center. The present invention relates to a method for measuring a size using a distance measurement by a laser beam. The present invention also provides an apparatus for producing metal powder by water spray, which makes it possible to obtain a metal powder having desired characteristics by controlling the inclination angle of a conical water film using this method. Also concerns.

[0002]

2. Description of the Related Art Metal powder is produced by a water spray method by spraying spray water at a high pressure from a nozzle having a circular slit in a direction inclined downward with respect to an axis toward the center of the circle to form a conical water. This is performed by forming a film, flowing the molten metal flow from the inside of the cone toward the apex, and finely pulverizing liquid metal droplets by collision with high-pressure water.

Conventionally, the inclination angle θ of the spray water stream with respect to the axis of the cone has been in the range of approximately 35 ° to 50 °. Generally speaking, when considering the energy efficiency of pulverization of a molten metal by a water flow, the efficiency is higher at an angle closer to 90 °, but at an angle of more than 50 °, an upward component force is generated at the collision point, and the molten metal flow is blown up and sprayed. There is an upper limit of 50 ° due to the problem of not being performed properly, and from the viewpoint of increasing energy efficiency within a range where this problem does not occur, 35 ° is generally adopted as the lower limit.

The inventor has broken such common sense and found that θ = 1
When spraying water at a small angle of 0 ° to 30 °,
While maintaining the advantage of the water spray method that a small-diameter powder can be obtained, it has been found that a powder having a shape close to a sphere and a ratio of 1.5 or less in terms of a long diameter and a short diameter can be overwhelming powder. Thus, a method for producing a metal powder by such water spraying was proposed (Japanese Patent Application No. 8-68766).

When water is sprayed with a conical water film having a small inclination angle as described above, in order to secure the effect of the invention and obtain a powder of a desired shape, the inclination angle is accurately controlled. There is a need. The control of the cone tilt angle measures the tilt angle and feeds back the result,
This is performed by adjusting the distance between the fixed member and the movable member that form the slit of the nozzle. Therefore, it is important to correctly measure the inclination angle of the conical water film in implementing the new water spray method.

[0006] The inclination angle of the conical water film is measured by measuring the height of the cone. In FIG. 2, when the radius of the circular nozzle is r and the distance from the plane including the nozzle outlet to the vertex of the cone, that is, the height of the cone is l ₀ , the inclination angle θ is θ
= It can be calculated as arctan r / l _0.

Heretofore, the following method has been used to find l ₀ . That is, from the back of the nozzle, go down the appropriate rod on the axis of the cone, and know that the tip of the rod touched the water film by the impact felt at that time, such as the rod being pulled in, and on the axis Using a vernier caliper, measure the length of the bar below the specific position, and use L =
Knowing the length of l ₀ + l ₁ and measuring l ₁ in advance
L ₀ is obtained according to the length of.

[0008] Such a measurement method is troublesome, requires skill and is dangerous. This is because a water stream jetted at a high pressure has a strong shearing force.

[0009]

SUMMARY OF THE INVENTION A general object of the present invention is to provide a method for producing a metal powder by the above-described water spray method, particularly when a new production method using a water film having a small inclination angle is carried out. It is an object of the present invention to provide a means for measuring the inclination angle of a conical water film simply and without any skill, in response to the need that arises in performing the work.

A specific object of the present invention is an apparatus for producing a metal powder by a water spray method utilizing the above-described measuring method, wherein a desired shape is formed by forming a water film having a controlled inclination angle. It is an object of the present invention to provide an apparatus which facilitates obtaining a metal powder of (1).

[0011]

SUMMARY OF THE INVENTION A method of measuring the inclination angle of a conical water film according to the present invention is to jet a water stream from a circular nozzle toward a center of a circle and in a direction inclined with respect to an axis passing through the center. A method of measuring the magnitude of the inclination angle of the conical water film formed by the above, with respect to the axis, fixing a laser type distance measuring device on the axis behind the nozzle, from the inside of the conical water film to the top Measure the distance from this measuring instrument to the vertex of the conical water film by irradiating the laser beam toward the top, the distance from the plane containing the circle of the nozzle given by the measured value to the vertex, and the nozzle known in advance And calculating the inclination angle based on the diameter.

As shown in FIG. 1, the apparatus for producing metal powder of the present invention utilizing the above-mentioned method is formed of a fixed member and a movable member, which are known per se, and adjusts the distance between both members. Spray water nozzle (1) having a circumferential slit capable of changing the ejection angle by performing the above operation, and having a passage in the center for the molten metal to fall, below the spray water nozzle Spray chamber (2) provided,
A laser type distance measuring device (3) removably disposed above the nozzle and formed on the axis of a cone formed by a water flow ejected from the nozzle, and a conical water film which is disposed alternately with the distance measuring device. Means for supplying spray water to the spray water nozzle, consisting essentially of a metal melt vessel (not shown) with a valve at the bottom for flowing the stream of metal melt towards the apex, and Means (not shown) for carrying away the mixture of the metal powder and water are added below.

[0013]

The distance measurement using laser light is widely performed today because it can be easily performed and has high accuracy.
However, when the target is such that a laser beam reflects at a low rate and is almost transmitted, such as a water film,
Laser type distance measuring devices are practically unusable.

The inventor of the present invention concluded that at the apex of the conical water film used for the production of metal powder, water and air were finely mixed due to the violent turbulence caused by high-pressure water collision. Focusing on the fact that, when irradiating a laser beam in such a state, the experiment was performed with the expectation that the laser beam would be reflected at a higher rate, unlike a normal water surface. This expectation is correct when measuring the laser distance in an arrangement as shown in FIG.
It was confirmed that the distance L from to the top (4) of the conical water film could be measured.

Using this principle, the inclination angle θ of the water film with respect to the axis of the cone is calculated by the above equation.
By feeding back the data and adjusting the slit gap, the tilt angle of the conical water film can be controlled to produce a metal powder having a desired shape.

[0016]

[Example] For a device practically used for the production of metal powder by water spraying, a distance measuring device using a laser "..."
(...) were attached as shown in FIG. A microcomputer designed to take the measured value and perform the above-described calculation was prepared, and combined with a distance measuring device, the apparatus was configured so that the inclination angle could be directly read simultaneously with the measurement.

Water with a pressure of 500 kg / cm ² is jetted from the water spray nozzle, and the slit is adjusted so that the angle of inclination of the water film with respect to the axis varies within a range of 15 ° to 50 ° by design. did. The distance L in FIG. 2 was measured by this method, and the inclination angle of the water film was calculated based on the result.
At the same time, the conventional distance measurement using a bar and a caliper was also performed.

With respect to the inclination angle, the relationship between the design angle of the water spray nozzle and the actually measured angle by the above-mentioned new and old methods was plotted, and the graph of FIG. 3 was obtained. Inclination angle 15 ° to 50 °
Sufficient agreement was found between the two in the range of, and it was confirmed that the inclination angle of the conical water film could be accurately measured by distance measurement using laser light.

[0019]

According to the method of the present invention, the inclination angle of the conical water film with respect to the axis can be measured simply, quickly and safely without skill. By using the metal powder manufacturing apparatus of the present invention utilizing this method, not only water spraying conventionally performed in general, but also a shape controlled by using a water film having a smaller inclination angle proposed earlier by the inventor. A new water spray to obtain a powder of is also easily implemented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a metal powder production apparatus according to the present invention.

FIG. 2 is a view for explaining the principle of the measurement method of the present invention performed using the apparatus of FIG.

FIG. 3 is a graph showing data of an example of the present invention, in which a relationship between a design angle of a water spray nozzle and an actually measured angle is plotted.

[Explanation of symbols]

Reference Signs List 1 spray water nozzle 2 spray chamber 3 laser type distance measuring device θ tilt angle of water film r radius of nozzle circle L distance from distance measuring device to apex of cone l ₀ distance from plane including nozzle to apex of cone ( distance height of the cone) from l ₁ distance measuring instrument to the plane containing the nozzle

Claims (2)

[Claims] 1. A method for measuring the angle of inclination of a conical water film formed by ejecting a water flow from a circular nozzle in a direction inclined toward an axis passing through the center toward a center of the circle and with respect to the axis. A laser type distance measuring device is fixed on the axis behind the nozzle, and a laser beam is irradiated from the inside of the conical water film toward the apex to a distance from the measuring device to the apex of the conical water film. And calculating a tilt angle based on a distance from a plane including a circle of the nozzle given by the measured value to a vertex and a nozzle diameter known in advance. 2. A metal slit is formed by a fixed member and a movable member, and has a circular slit capable of changing an ejection angle by adjusting a distance between the two members. Spray water nozzle with a passage for performing, a spray chamber provided below this spray water nozzle,
A laser light distance measuring device removably disposed on the axis of a cone formed by a water stream ejected from the nozzle above the nozzle, and alternately disposed with the distance measuring device toward a vertex of the conical water film; Means for supplying spray water to a spray water nozzle, and a mixture of metal powder and water below the spray chamber, consisting essentially of a metal melt vessel with a valve at the bottom for flowing down the metal melt flow For producing metal powder by water spraying, which is provided with a means for carrying away water.