JPH0582441B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a spray device for producing powder from molten metal, and in particular to a spray nozzle. [Prior art] When molten metal is sprayed using a ring nozzle, the most important thing is the water film formed by the water jet ejected from the nozzle, and the characteristics of the resulting metal powder are influenced by the characteristics of this water film. be done.
Particularly when trying to obtain powder with a low apparent density, a water film that is as uniform as possible is required in the entire circumferential direction of the ring nozzle. Various spray nozzles for manufacturing metal powder have been proposed in the past, but among them, a spray device equipped with a dynamic pressure control ring and an adjustment guide has been proposed to obtain a uniform water film (Japanese Patent Publication No. 43 −6389). In addition to this spray device,
It has been proposed (Japanese Patent Publication No. 52-19540) that converts the jet liquid emitted from a plurality of pencil-type spray nozzles into an inverted cone-shaped water film using a creeping guide.
However, in the case of a spray device equipped with a dynamic pressure control ring and an adjustment guide, when high-pressure water is introduced from one or two high-pressure pipes, this high-pressure water is decelerated once by the dynamic pressure control ring. After the pressure has been made uniform, the water is ejected from the spout, but in this case, uniformity of water flow in the chamber on the spout side cannot be obtained. This non-uniformity remains even in the high-speed jet ejected from the jet nozzle. In other words, if the width of the gap between the dynamic pressure control ring and the ring nozzle body is 0.2 mm or more, the flow of high-pressure water introduced from one or two directions will be strong only in the direction of introduction, and the resulting water film will be The focal point is not a point, but a long figure 8-like shape perpendicular to the direction of introduction. In the method using a dynamic pressure control ring, the width of the gap needs to be 0.2 mm or less to ensure uniformity of water flow, and if it is less than 0.2 mm, the resistance due to the dynamic pressure control ring will increase, resulting in a large pressure loss. The loss is approximately 60 kg/cm ² or more compared to the case without a dynamic pressure control ring. Furthermore, the dynamic pressure control ring may be deformed not only by the pressure loss but also by the pressure difference before and after the dynamic pressure control ring, causing the inside of the ring to become clogged and damaging the nozzle or pump. Such non-uniformity of water flow coming from the high-pressure water introduction direction can be improved by increasing the ratio of the cross-sectional area of the high-pressure water inlet to the cross-sectional area of the jet nozzle, but if the cross-sectional area of the jet nozzle is constant In this case, there is a limit to the cross-sectional area of the inlet port due to the size of the nozzle, which poses many practical problems. On the other hand, in a spray nozzle that does not straighten the flow inside the spray nozzle, but instead transforms the injected impulse into an inverted cone-shaped water film using a creeping guide,
Since the direction of the high-speed jet is changed by a creeping guide, there are problems such as a large energy loss and a decrease in the ability to powder the molten metal. [Problems to be Solved by the Invention] In order to solve the technical problems with the conventional ring nozzles, the present inventors have investigated various spray nozzles that are as uniform as possible and have less energy loss, and have found that the ring nozzle The present invention was completed based on the discovery that the objective can be achieved by installing a flow equalizing ring and a rectifying ring inside the nozzle. [Means for Solving the Problem] The present invention has four or more dividing holes and a flow direction of the spraying medium flowing out from the dividing holes, from when the spray medium is introduced into the spray nozzle until it reaches the spout. This is a ring nozzle for manufacturing metal powder, characterized in that a flow equalizing ring and a flow straightening ring are provided in which the number of flow straightening holes is twice or more the number of dividing holes in the direction of change. [Operation] The present invention will be described in more detail as follows with reference to FIG. The inside of the nozzle has a flow equalizing ring and a rectifying ring, which characterize the present invention, and the inside of the nozzle is divided into four chambers by these rings. For purposes of explanation, the order in which high-pressure water flows through this chamber is the high-pressure water inlet, high-pressure water guide chamber, division chamber, rectification chamber,
It is called the pre-ejection chamber. First, high-pressure water led into the nozzle from the high-pressure water inlet enters the high-pressure water introduction chamber and is led around the entire circumference. Then, it passes through the dividing hole provided in the flow equalizing ring and is guided to the dividing chamber. In this case, it is desirable to provide 4 to 12 dividing holes at equal intervals within the same plane at positions different from the high-pressure water introduction direction and the perpendicular direction thereof.By selecting the optimal position and number in this way, The high-pressure water is introduced into the divided chambers, with the strong directionality in the initial introduction direction being canceled. Although the flow velocity of the high-pressure water introduced into the division chamber is reduced, the uniformity of the flow is improved. Further, the high-pressure water exits the dividing chamber and is finely divided and rectified by the rectifying holes that have the same role as the dividing holes. In this case, it is desirable that the rectifying holes be located in a direction perpendicular to the dividing holes and at a different position from being on the same axis, and that the number of the rectifying holes be at least twice the number of dividing holes. It is necessary to design a ring nozzle with a structure in which the sum of the step areas of the high-pressure water inlet, the dividing hole, and the rectifying hole is approximately equal. can get. Next, the high-pressure water finely divided by the rectifying holes is guided to the rectifying chamber, the speed is reduced again, and the water is guided from the rectifying zone in the gap between the rectifying ring and the nozzle body to the pre-jet chamber. In order to reduce pressure loss and improve the rectification effect, the cross-sectional area of this rectifying zone is preferably approximately equal to the high-pressure water inlet, and the width of the gap is preferably 0.5 to 1 mm. As mentioned above, the high-pressure water introduced into the high-pressure water introduction chamber from the high-pressure water introduction port and guided to the pre-jet chamber through the flow equalization ring and the rectification ring has a strong initial directionality in the high-pressure water introduction chamber 6. canceled out,
The water flow is uniform in the entire circumference direction. The water flow that has been made uniform before the jet nozzle is ejected from the jet nozzle, forming an inverted conical water film water jet that is highly uniform around the entire circumference. This stabilizes the water film, increases the concentration of the water jet, and increases the energy efficiency of the nozzle. That is, the energy of the water jet is effectively used to deform and cool the molten metal, and the powder obtained using this water film is made into fine particles. [Example, Comparative Example] To confirm uniformity using the ring nozzle of the present invention shown in Fig. 1, the cross-sectional area of the spray port was made equal to the cross-sectional area of the high-pressure water inlet, and the rectification band gap was set to 0.5.
High pressure water was introduced from the high pressure water inlet.
At this time, since the cross-sectional area of the jet port and the high-pressure water inlet are made equal, the pressure appearing on the pressure gauge connected to the high-pressure water inlet is mostly due to the resistance of the piping and the resistance inside the nozzle, that is, the rectifier ring and the rectifier ring. This can be considered to be due to the resistance caused by As a result of the test, this pressure was 21 Kgf/cm ² . Furthermore, the water flow jetted out from the spout of the ring nozzle was uniform and stable. On the other hand, as a comparative example, a ring nozzle of the same type as in Japanese Patent Publication No. 43-6389 was used, and the dynamic pressure control ring clearance, which corresponds to the rectifying band clearance of the present invention, was set to 0.5 to 0.3 mm, and the same pressure as that of the present invention was set. The uniformity and stability of the ejected water stream were observed. The results are shown in Table 1 for comparison.

[Table] Furthermore, using the ring nozzle of the present invention and the ring nozzle of the comparative example, the ejection pressure was 150 Kgf/cm ² for both.
A molten Cu-10%Sn alloy was atomized with a diameter of 8 mm. Table 2 shows a comparison of the characteristics of the powder obtained by this atomization.

【table】

〔Effect of the invention〕

As described in detail above, the ring nozzle incorporating the flow equalizing ring and rectifying ring of the present invention is an industrially useful invention as it can provide a uniform water film and perform stable atomization with little energy loss.

[Brief explanation of the drawing]

FIG. 1 is a cross-section of a ring nozzle incorporating the flow equalizing ring and rectifying ring of the present invention. FIG. 2 is a plan view of the flow equalizing ring. ...divided hole, ...straightening hole, ...balance ring, ...straightening ring, ...high pressure water inlet,
……High water pressure introduction chamber, ……Divided chamber, ……Rectification chamber, ……Pre-spray chamber, ……Adjustment guide, ……
Rectification zone, ... high pressure water introduction direction, ... spout.

Claims (1)

[Scope of Claims] 1. Split into four or more dividing holes from the time the spray medium is introduced into the spray nozzle until it reaches the spout, and in a direction that changes the flow direction of the spray medium flowing out from the dividing hole. A ring nozzle for producing metal powder, characterized in that it is provided with a flow equalizing ring and a rectifying ring provided with a number of rectifying holes that is twice or more the number of holes. 2. The ring nozzle for producing metal powder as set forth in claim 1, wherein the flow equalizing ring and the rectifying ring are integrally constructed.