JPS5845299B2 - liquid atomization device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for atomizing a liquid using compressed gas.

Atomization of liquids is used in many ways, such as spraying paint, heavy oil combustors, vaporizers, and various types of atomizers.

As a sprayer that crushes and atomizes such liquid,
Conventionally, liquid pressurized sprayers have been widely used.

This is done by swirling the liquid and injecting it through small holes.
Liquid is split into fine particles by centrifugal force.

However, although this liquid pressurization type sprayer has no problem when used at a constant flow rate, it causes various damage when used with varying liquid volume.

For example, when the liquid flow rate is reduced, the required pressurizing force decreases in proportion to the square root of the flow rate, but due to the decrease in centrifugal force, the diameter of the spray droplets increases, and the spread of the spray narrows, maintaining the original spray state. You won't get any more.

When it is desired to obtain the same particle size even if the liquid flow rate is changed in this way, or when it is desired to obtain fine droplets using a low-pressure liquid, it is effective to use a two-fluid atomizer.

This two-fluid atomizer uses a high-speed air fluid to blow away a liquid column or large droplets into fine particles.The larger the volume ratio of gas and liquid and the relative velocity between air and liquid flows, the more effective the atomization becomes. big.

However, in conventionally known m=fluid sprayers, the liquid discharge port is almost a single circular hole. As a result, the ejected liquid column becomes thick or the droplet diameter becomes large, and a very large amount of high-pressure gas is required to crush this into fine particles.

The present invention solves the problems in conventionally known two-fluid atomizers, and changes the state of large flow rate and large particles to small flow rate and fine particles by simply changing the liquid volume at low liquid pressure, small gas volume, and low gas pressure. It can be easily produced by controlling only one person.

The present invention achieves these objects by inserting a core into the liquid discharge port at the tip of a liquid nozzle, and providing a projection with a smaller diameter at the lower part of the core than the upper part to form a gap between the inner wall of the liquid discharge port and the projection. The nozzle body is characterized in that an annular slit is formed in the nozzle body, the cross-sectional area of the nozzle body is gradually narrowed toward the bottom, and a spray port is provided at the bottom end of the nozzle body.

Embodiments of the present invention shown in the drawings will be described below.

FIG. 1 is a sectional view of an embodiment of the liquid atomization device of the present invention;
FIG. 2 is a bottom view thereof.

In the drawings, 1 is a nozzle member having a circular cross-sectional shape, and a lid 3 is attached to the lower side of the nozzle member 1, the cross-sectional area gradually narrowing toward the bottom, and having a spray nozzle 2 at the lower end. Both constitute a nozzle main body 4, and an air chamber 5 is formed inside the nozzle main body 4.

In this case, the outlet of the spray nozzle 2 is chamfered into a conical shape to serve as a guide for diffusing the liquid spray.

Reference numeral 6 denotes a compressed gas supply port for supplying compressed gas, which is attached tangentially to the upper part of the side surface of the nozzle body 4 like a cyclone, so that the gas flowing through the supply port 6 flows inside the air chamber 5. Turn at high speed.

7 is a liquid nozzle attached to the center of the upper part of the nozzle body 4 with a nut 8; this liquid nozzle 7 is inserted into the air chamber 5 from the upper part of the nozzle body 4; I want it.

Reference numeral 9 denotes a core inserted and fixed into the discharge port portion of the liquid nozzle 7, and one or more grooves 10 are formed on the outer periphery of the core 9.
is provided in a spiral shape, and the liquid that has descended from the top inside the liquid nozzle 7 is given a swirling force by passing through this groove 10.

11 is a narrow annular slit which forms the main part of the present invention, and this slit 11 is connected to the inner wall of the tip of the liquid nozzle 7,
It is formed by a cylindrical projection 9a provided at the lower part of the core 9.

Therefore, the liquid that has been given a swirling force by the spiral groove 10 swirls through the slit 11 and is discharged as a liquid film of uniform thickness.

Note that the compressed gas supply port 6 and liquid nozzle 7 include
The gas supply pipe and the liquid supply pipe are respectively connected by a screw method.

Next, spraying by the liquid atomization device having the above configuration will be explained.

The pressurized liquid supplied from the upper part of the liquid nozzle 7 is
A swirling force is obtained by passing through a spiral groove 10 provided on the outer periphery of the liquid nozzle 7, and the liquid is discharged as a cylindrical liquid film flow through a ring-shaped slit 11 at the tip of the liquid nozzle 7.

In this case, since the liquid film is discharged while swirling, centrifugal force is acting on itself, and the liquid film is about to break up and become droplets.

On the other hand, the compressed gas enters the air chamber 5 through the compressed gas supply port 6 tangentially attached to the nozzle body 4 and descends while rotating at high speed.

In this case, since the liquid nozzle 7 is located in the air chamber 5 and the cross-sectional area of the air flow passage is gradually narrowed toward the bottom of the air chamber 5, the swirling speed of the air flow gradually becomes faster.

Then, this accelerated and horizontally swirling airflow comes into contact with a cylindrical liquid film discharged vertically downward from the liquid nozzle 7 in the primary crushing chamber 5a at the lower part of the air chamber 5, and converts the liquid film into a small liquid. Split into drops.

Compared to the conventional method in which the liquid is discharged in the form of a column with a diameter larger than a single hole, this primary fragmentation of the liquid stream is easier to break up because the liquid is discharged in a thin film, and the droplets themselves become minute. .

Furthermore, in this case, the cylindrical liquid film itself is about to break up into small droplets due to centrifugal force, and the relative velocity between the liquid film and the high-speed swirling airflow is large, so the above splitting is more effective. It will be held in

Next, the droplets and airflow generated by the splitting pass through the spray nozzle 2 while swirling.

This spray nozzle 2 is made to have the smallest area through which the gas passes, so the gas velocity is maximum at that part, and the minute droplets formed by the -order fragmentation are secondary when passing through the nozzle 2. It is crushed and further atomized.

In this way, the gas exiting the spray nozzle 2 expands under reduced pressure, and due to the residual swirling force of the gas and droplets, the droplets are widely scattered.

In addition, in order to perform the secondary crushing most efficiently, it is necessary to
It is important to discharge the liquid film toward the periphery of the area.

FIG. 3 shows an embodiment in which this secondary crushing can be carried out more efficiently. In this example, the small-diameter protrusion 9a at the lower end of the core 9 is shaped like a cone that widens at the end, and the cylindrical liquid from the slit 11 is Considering that the diameter of the membrane is reduced by the swirling airflow, the extension line of the conical protrusion 9a is directed slightly outward from the periphery of the spray nozzle 2.

In this case, the bottom surface 9b of the small-diameter protrusion 9a of the core 9 is conically depressed to prevent liquid from dripping from other than the outer periphery of the small-diameter protrusion 9a of the core 9, that is, from the slit 11. Consideration has been taken to ensure that the liquid discharge forms a cylindrical liquid film.

Furthermore, in the example shown in FIG. 3, since the small-diameter protrusion 9a of the core 9 is formed into a conical shape that widens at the end, the small-diameter protrusion 9a can be adjusted by vertically adjusting the position of the core 9 itself.
It is also possible to adjust the width of the slit 11 formed by the tip of the liquid nozzle 7 and the tip of the liquid nozzle 7.

Adjusting the width of this slit 11 is important in adjusting the spray droplet diameter.

Note that when the amount of liquid is large, the slit can be formed into a double ring shape to increase the amount of liquid without increasing the slit width.

These adjustments are not possible with conventional single-hole liquid discharging methods, and are one of the advantages of the present invention.

Furthermore, it is desirable that the twisting direction of the spiral groove 10 on the outer periphery of the core 9 be opposite to the swirling direction of the airflow, in which case the relative velocity between the gas flow and the liquid flow will be greater than when the direction is set in the same direction. The droplet diameter can be made smaller.

As described above, according to the present invention, since the spiral groove 10 is provided in the core 9 inserted into the liquid discharge port of the liquid nozzle 7, the liquid to be atomized becomes a swirling flow, and this swirling flow The annular slit 11 formed between the cylindrical protrusion 9a provided at the lower part of the liquid slit 7 and the inner wall of the tip of the liquid slit 7 causes the liquid to be discharged as a cylindrical liquid film flow due to centrifugal force.

On the other hand, a compressed air supply port 6 is provided in the direction of the side surface of the nozzle body 4.
is provided, so the compressed air swirls at high speed inside the nozzle body 4, and since the cross-sectional area of the nozzle body 4 gradually narrows toward the bottom, the compressed air flow descends while swirling. The speed is gradually increased.

This accelerated airflow then comes into contact with the cylindrical liquid film flow, causing primary fragmentation in which the liquid film is broken into small droplets.

In addition, since the cylindrical liquid film flow is about to turn into droplets due to centrifugal force, and the relative velocity between the liquid film flow and the compressed air flow is large, and the swirling directions are opposite, the liquid film easily turns into minute droplets. crushed into pieces.

Furthermore, since the nozzle body 4 is narrowed toward the bottom and the spray nozzle 2 is provided at its lower end, the swirling airflow containing the droplets generated by the secondary crushing passes through the spray nozzle 2 with the smallest area. The flow velocity of the swirling air current reaches its maximum at the spray nozzle 2, and the droplets are further crushed secondary due to expansion when passing through the spray nozzle 2, becoming more fine.

In this way, the present invention combines the primary fragmentation of the liquid film flow and the secondary fragmentation of the formed droplets, and as a result, it is possible to reduce the flow rate from large particles to small particles by simply controlling the liquid volume. At a high flow rate, a spray liquid in the form of fine particles can be obtained.

Further, when the cross-sectional shape of the nozzle body 4 is made circular to correspond to the ring-shaped slit 11, the gas flow also becomes a swirling flow, so that the relative velocity between the gas flow and the liquid flow becomes larger, and the liquid can be atomized more efficiently.

Further, according to the present invention, by adjusting the width of the slit 11, the diameter of the spray droplets can be adjusted, which is a unique effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the device of the present invention, FIG. 2 is a bottom view thereof, and FIG. 3 is a sectional view showing another embodiment of the device of the present invention. 1... Nozzle member, 2... Spray port, 3... Lid, 4
... Nozzle body, 5... Air chamber, 6... Compressed gas supply port, 7... Liquid nozzle, 9... Core, 10...
Spiral groove, 11... annular slit.

Claims (1)

[Claims] 1 Consisting of a nozzle body having a spray port at the lower end, and a liquid nozzle inserted into the nozzle body from above toward the spray port, the nozzle body has a compressed gas supply port in the linear direction of the side surface, and The cross-sectional shape of the liquid nozzle is circular, and its cross-sectional area gradually narrows toward the bottom to reach the spray port, and a core is inserted into the liquid discharge port at the tip of the liquid nozzle, and the core is a spiral groove having a spiral direction opposite to that of the compressed gas flow supplied from the compressed gas supply port on the upper outer periphery;
A liquid atomization device characterized in that a lower part is provided with a protruding part having a smaller diameter than the upper part, and an annular slit is formed between the inner wall of the liquid discharge port and the protruding part.