RU207898U1 - Anti-satellite auto nozzle - Google Patents

Abstract

The utility model relates to the field of powder metallurgy, in particular, to the production of powders by spraying the melt with gas. The atomizer nozzle includes a body with openings for gas supply, an annular collector located in the said body, an insert that forms a circular channel for gas supply to the atomization region. In the lower part of the body there is an annular channel of variable thickness from 0.1 to 0.3 mm along the gas flow with swirlers, which are ribs with a width of 0.9 mm, located at an angle of 19 ° to the central axis of the nozzle. The useful model provides a decrease in the number of satellites in the powder mass and an increase in the yield of a suitable product due to the leveling of the throw of small particles into the region of atomization of the melt. 3 C.p. f-ly, 3 dwg.

Description

The utility model relates to the field of powder metallurgy, in particular to devices for the production of powders by spraying liquid metal (melt) with a gas (atomization).

In powder metallurgy, installations are used to obtain powder by spraying the melt with gas (atomizers). Such installations have different design features, but they all have certain identical structural elements, in particular, they always use a nozzle to supply gas to the atomization area. The designs of the nozzles may vary, but they are always divided into two types, depending on the effect of the gas flow on the melt jet: with a free-falling melt jet and with a limited melt jet. In the first case, the nozzle creates a gas flow that converges at a certain point of convergence and breaks the melt jet into droplets. In the second case, the gas flow does not break directly, but flows around the melt jet, creating disturbances in it and, thereby, breaking it into drops. Gas flow rates can be up to Mach 2. The most effective and widely used are the nozzles of the second type.

The process of gas spraying using the second type of nozzles can be described as follows. The melt enters the atomization area from the central hole in the nozzle. The melt atomization region consists of three zones. The first recirculation zone, where, under the action of the gas jet, it is partially recirculated before it enters the second zone. The second zone is the zone of the primary splitting of the melt, where the jet is broken due to the flow around the gas flow coming out of the nozzle, and the gas can come out both from the nozzles isolated from each other and from the annular channel. In the third zone, the zone of secondary melt splitting, an additional secondary splitting of melt droplets occurs. In this case, the droplets of the melt fly off after breaking, forming a spray cone bounded by an external containment layer, that is, by an external gas flow. When the melt jet breaks up, vortices are formed at the edges of the atomization region, partially restrained by the outer layer. The vortexes throw the fine powder back into the atomization area, where it adheres to the larger powder particles that form there, increasing the number of satellites in the powder mass.

Known nozzle design, described in US patent 4880162, publ. 11/14/1989 В05В 7/06. The design of the nozzle is as follows. The cylindrical body contains inside the device in order to tangentially direct the gas coming from the outside into the cavity in the inner wall of the cylinder with tangential gas channels equipped with special devices for adjusting the total volumetric gas flow rate through the nozzle. The flow guide insert and the flow guide plate are located on the inner side of the cylindrical body, located near the cavity and combined with it, while the flow guide insert can be positioned differently relative to the flow guide plate to control the width of the spray zone. The angle of convergence (convergence) of the gas at the outlet of the nozzle to the stream of molten metal passing through the central hole can be varied by changing the shape guiding the flow of the insert and / or guiding the flow of the plate. Distinctive features of the nozzle are that the design allows you to vary the angle of convergence of the gas to the stream of molten metal and the total volumetric flow rate of the gas through the nozzle, while controlling it with high accuracy.

The main disadvantage of this nozzle is the complexity of the design of the product, in which it is difficult to ensure a high yield of a suitable powder of the required fraction, and the lack of control of additional eddies that appear during the splitting of the melt jet, which throw small powder particles into the atomization region, which leads to the formation of satellites and reduces yield of good powder.

From the prior art, the design of an atomization device is known, presented in patent EP 0440706, publ. 08/02/1995, В05В 7/08; В05В 7/16; B22D 23/00; B22F 3/115; B22F 9/08. The main element of the device is a rotor that supplies gas to the atomization zone, and the peculiarity of this supply is the possibility of varying the gas flow relative to the melt flow, realized by changing the position of the rotor. To ensure control of the shape of the resulting flow in the modification of the presented device, an additional installation of the second rotor in the design is proposed.

From the prior art, the design of an atomization unit is known, presented in US patent 6667246 B2, publ. 10.08.2004, B22F9 / 08. The main distinguishing feature of the plant is the presence of primary nozzles for dispersing the melt flow and secondary nozzles for controlling the shape of the flow during dispersion.

The disadvantages of both designs are the complexity of their execution and control of their functioning, which leads to instability of the atomization process.

The closest analogue of the claimed utility model is a nozzle including a body with holes for gas supply, an annular gas vortex cavity located in the body, an insert that forms a circular channel for gas supply to the atomization region. The metal melt is fed through the central hole in the nozzle and through it into the atomization area. The gas is delivered to the atomization area under high pressure in a jet. Gas for atomization is directed towards the lower end of the tube, deviates from it and then comes into contact with the flowing down gas stream (US 4619597, publ. 28.10.1986, B05B 7/06).

The main disadvantage of this nozzle is the absence of an obstacle for additional eddies that appear in the process of splitting the melt jet, which throw small powder particles into the atomization region, which leads to the formation of defective powder particles and reduces the yield of suitable ones.

The technical task of the claimed utility model is to create an atomizer nozzle with an anti-satellite system that reduces the number of satellites in the powder mass due to the formation of a secondary vortex in the atomization region around the main gas flow.

The technical result of the claimed utility model consists in the formation of a configuration of gas flows after the proposed atomizer nozzle in such a way that the secondary vortex creates a barrier impermeable to fine powder particles, thereby reducing the number of satellites in the powder mass and thereby increasing the yield of a suitable product.

The atomizer nozzle includes a body with openings for gas supply, an annular collector located in said body, an insert that forms a circular channel for gas supply to the atomization region. The set technical result is achieved by the fact that in the lower part of the body there is an annular channel with a thickness of 0.1 to 0.3 mm with swirlers representing ribs with a width of 0.8 to 1 mm, located at an angle of 18 ° to 20 ° to the central axis of the nozzle.

In an embodiment, the insert, which forms a circular gas supply channel to the atomization region, is located coaxially inside the housing.

Preferably, one edge of the inner side of the housing extends into an annular manifold. The swirlers can be arranged radially symmetrically to the gas supply holes.

The declared utility model is illustrated by drawings:

fig. 1 is a side view of the nozzle, in section (view A-A);

fig. 2 - top view of the nozzle, in section (view B-B);

fig. 3 is a diagram of the atomization process (configuration of gas flows), using the declared nozzle.

The proposed atomizer nozzle includes a nozzle body 1 with holes 2 for gas supply located in a circle. Gas through the holes 2 enters the annular collector 3 of the gas swirl. An opening 5 is located in the lower part 4 of the housing, from which the melt stream flows out. The diameter of the hole 5 is preferably 6 to 14 mm. The inner side 6 of the housing 1 has the shape of a truncated cone, one edge smoothly extending into the annular collector 3. The other edge of the inner side 6 goes into the hole 5. The insert 7, guiding the gas flow, is placed inside the specified housing 1 coaxially, forming a circular channel 8 for gas supply to area of atomization. The circular channel 8 is formed by the inner part 9 of the insert 7, made in the form of a truncated cone, having a deviation from the inner side 6 of the specified housing 1 of 2-3 °. In the lower part 4 of the housing 1 there is an annular channel 10 with swirlers 11. The number of swirlers can be from 12 to 16. The annular channel 10 with one end goes into the annular collector 3, and the other into the atomization region through the inner side of the lower part 4 of the housing 1, made in the form of a truncated cone. The annular channel 10 has a variable thickness from 0.1 to 0.3 mm along the gas flow. Swirlers 11 are ribs with a width of 0.8 to 1 mm, located at an angle (item 12 in Fig. 1) from 18 ° to 20 ° to the central axis of the nozzle. The geometry of the annular channel 10 with swirlers 11 makes it possible to regulate the rate of gas outflow from it, providing the creation of additional gas flows that form a secondary vortex around the main area of atomization. A certain part of the gas leaves the annular collector 3 into the annular channel 10, reducing the gas pressure in the annular collector 3 and, thereby, reducing the gas velocity at the outlet of the circular channel 8.

The principle of operation of the declared injector is as follows. The melt is fed through a central hole in the nozzle and through it into the atomization area. Gas enters the gas swirl collector 3 through the gas supply holes 2, due to the geometry of the device, it is distributed in this circular cavity, and the counter flows formed after the collision of the gas flows with the wall of the annular collector 3 from adjacent branches 2 lead to the gas flow swirl. Then, through the circular channel 8, the gas enters the atomization region, while the convergence angle is 45-65 °. Part of the gas enters the annular channel 10, and, thanks to the swirlers 11, forms a secondary vortex in the atomization region around the main gas flow. This vortex creates a barrier that is impervious to fine powder particles. Thus, the throwing of small particles into the region of atomization of the melt is leveled and, thereby, the number of satellites is reduced and the yield of suitable powder increases.

As an example of the implementation and achievement of the technical result, FIG. 3 shows the result of a numerical experiment of the proposed nozzle design for an atomizer for organizing gas flows. Numerical experiments were carried out for the above-mentioned variable thickness of the annular channel 10, the interval of the width of the ribs of the swirlers 11 and the interval of their angle to the central axis of the nozzle. The results of numerical experiments in the indicated ranges of values of the design features of the proposed atomizer are visually similar. Analysis of the experimental results showed that the atomization process with the proposed nozzle design shown in Fig. 3, which shows the area of melt atomization and a secondary vortex, leveling the ingress of small powder particles into it to achieve a technical result.

The proposed nozzle can be manufactured using additive technologies, namely, synthesis on a substrate (selective laser fusion).

Claims (4)

1. Nozzle for an atomizer, including a body with holes for gas supply, an annular collector located in the said body, an insert forming a circular channel for gas supply to the atomization region, characterized in that an annular channel of variable thickness from 0.1 is made in the lower part of the body. up to 0.3 mm along the gas flow with swirlers, which are 0.9 mm wide ribs located at an angle of 19 ° to the central axis of the nozzle. 2. A nozzle according to claim 1, characterized in that the insert, which forms a circular channel for supplying gas to the atomization region, is located coaxially inside the housing. 3. The nozzle of claim. 1, characterized in that one edge of the inner side of the housing extends into the annular manifold. 4. The nozzle according to claim. 1, characterized in that the swirlers are located radially symmetrically to the holes for the gas supply.

Images