A two-phase flow nozzle, having limited dimensions of main parts relating to size of atomized particle and having correction means to assure the height of a gap of a gas exit, wherein said gap is formed between a lower surface of a gas nozzle and an upper surface of a liquid nozzle is provided. The nozzle is composed with the first liquid passage, the liquid nozzle with a liquid splaying exit, a concave located at an end of the liquid nozzle where said liquid exit is located lower than said end of liquid nozzle, a gas nozzle having a gap to supply compressed gas for atomizing from the outer periphery of said liquid nozzle to the liquid injected from said liquid exit, and having a gas exit, wherein said gap is formed by sticking the minute spherical extrusion composed integrally on said liquid nozzle with a lower surface of said gas nozzle. Further, the contact of said minute spherical extrusion with said upper surface of gas nozzle is automatically corrected by supporting a convex spherical supported surface, which is provided at an intermediate portion of said liquid nozzle, with a concave spherical supporting surface, which is provided at an upper inner peripheral edge of a liquid nozzle holder.

FIELD OF THE INVENTION

This invention relates to a two-phase flow nozzle, more particularly, an injection nozzle to atomize mixed flow of liquid and gas. In detail, it is suitable for the use of painting equipment, fuel burning equipment, humidifier, steam iron, cooling fan using latent heat of evaporation or lubrication device for machine tools, etc.

DESCRIPTION OF THE RELATED ART

JP Utility model 3202161 and U.S. patent Ser. No. 10/335,811 disclose a related art of two-phase flow nozzle as shown onFIG. 7. As shown inFIG. 7(a), a two-phase nozzle1has a liquid nozzle5, a gas nozzle13and an outer case20. Further, as shown inFIG. 7(a),FIG. 7(b)andFIG. 7(c), the liquid nozzle5is composed with an upper portion with a larger diameter5a, a lower portion with a smaller diameter5band a first liquid passage10which penetrates inside of it vertically. A liquid nozzle holder7is provided inside of the outer case20, where said liquid nozzle holder7is composed of a base part7aand an upper part with a smaller outer diameter7bextending upwardly from said base part7a, a cylindrical liquid nozzle containable space7clocated at the upper portion with the smaller outer diameter, a second liquid passage8extending from a base end of said base part7ato a bottom end of said liquid nozzle containable space7c, wherein the outer diameter of the upper portion with the larger diameter5aof said liquid nozzle5and the outer diameter of the upper part with the smaller outer diameter7bof said nozzle holder7are the same.

The lower portion with the smaller diameter5bof said liquid nozzle5is fitted with a slight clearance (loosely fitted) to said liquid nozzle containable space7cin said nozzle holder7, where a lower surface of the upper portion with the larger diameter5a, of said liquid nozzle5is stuck on an upper surface7dof the upper part with the smaller outer diameter7b, which is perpendicular to the second liquid passage8of the liquid nozzle holder7.

A liquid spraying exit10ais composed at a top end of said first liquid passage10. An upper surface22of the liquid nozzle5is perpendicular to said first liquid passage10, where a plurality of extrusions23having a minute height δ are provided.

Said gas nozzle13is composed with a circular disc portion13aand a hollow circular cylindrical portion13belongated from the outer periphery of said circular disc portion13ato the lower direction. At the center of said circular disc portion13a, a gas exit14is formed, where in an inner peripheral surface of said hollow circular cylindrical portion13b, a female screw13cis formed. The eccentricity of a center axis14aof said gas exit14with a center axis14bof said first liquid passage10is desirable to be parallel and equal or less than 10% of the diameter of said first liquid passage10. Especially, it is more preferable that both axes are coaxial.

At the outer periphery of the nozzle holder7in said outer case20, a pillar like containable space21for containing the liquid nozzle holder7is provided. The base part7awith a larger outer diameter of said nozzle holder7is installed in said liquid nozzle containable space21with a slight clearance. Further, on an upper periphery of said outer case20, a male screw20ato mate the female screw13con said gas nozzle13is formed.

As shown inFIGS. 8(a)and (8b), when said gas nozzle13is fastened to the upper periphery of the outer case20by the female screw13cand the male screw20a, the lower surface of the circular disc portion13ais stuck on a extrusion23which is composed on a part of the upper surface22of said liquid nozzle5having a minute height δ, wherein a gas exiting gap17is formed, in a space without said extrusion23, between the upper surface22of said liquid nozzle5and the lower surface of the circular disc portion of the gas nozzle13.

As shown inFIG. 7, a gas passage16to communicate with said gas exiting gap17is formed between an inner wall of said containable space21of said outer case20and the upper portion with the large diameter part5aand between the inner wall of said liquid nozzle containable space21of said outer case20and the outer wall of the upper part with a smaller outer diameter7bof said nozzle holder7. On the outer periphery of said outer case20, a gas feeding tube15is composed to direct gas to said gas exit14inclining to the center axis of the gas exit14, where said gas feeding tube15is communicate with said gas passage16.

On a lower portion of said outer case20, a liquid feeding passage9is composed integrally with said outer case20. On the center of said liquid feeding passage9, a third liquid passage25is formed and communicates to said second liquid passage8.

As shown inFIG. 8, a circular liquid nozzle recess12is composed in the top of the liquid nozzle5around the center axis of the liquid spraying exit10a, where the liquid spraying exit10ais located slightly lower than the top end of the liquid nozzle5. The compressed gas injected through said gas exiting gap17shears the compressed liquid injected from the liquid spraying exit10aand atomizes the liquid, where the pressure of the gas in the liquid nozzle recess12becomes negative, so that a part of the gas to atomize which injects from the gas exit14of the gas nozzle13, produces a turbulent flow around the liquid spraying exit10a. As this turbulent flow crosses the main liquid flow injected from the liquid spraying exit10aand produces turbulent in the liquid, a mist of fine particles can be obtained by using gas with low pressure and low rate of discharge.

For instance shown inFIG. 7, in case of that the liquid is water and the gas is air, the diameter of first liquid passage10(liquid spraying exit10a): A=0.6 mm, the water pressure is 100 kPa, gas pressure is 90 kPa, the diameter of the liquid nozzle recess12: .B=1.2 mm, the depth of the liquid nozzle recess12: D=0.6 mm, the diameter of the gas nozzle13: .C=0.9 mm, .δ.=0.06 mm, rate of discharge of air is 4.9 l/min, rate of water flow is 7.5 ml/min, fine atomized particles sized 10˜30μ are obtained.

Further, it is found that by experiments, it is desirable that C/A=1.25˜1.55, B/C=1.25˜2, and D/A=0.2˜1.0.

The most important dimension is the height .δ. of the fine extrusion23to form said gas exiting gap17. It is desirable that δ/A=0.08˜0.15, but it may be determined in accordance with the object of application. In the best illustrated case, δ is 0.06 mm. Further, because the gas nozzle13is fastened by a screw to the outer case20so as the lower surface of the circular disc portion13ais stuck to the extrusion23of the liquid nozzle5, the height δ of the gas exiting gap17, which is the minimum clearance, depends only on accuracy of the height δ of the extrusion23. The extrusion23formed on the liquid nozzle5is made by molding process of plastics or machinery process of metals integrated with the liquid nozzle5, accuracy of the height δ. can be easily secured.

Further, when the gas nozzle13is fastened so as the inner surface of the gas nozzle is stuck to the extrusion23, a slight clearance27is made between the upper surface of the outer case20and the lower surface of the circular disc portion13aof the gas nozzle13. Said slight clearance prevents said lower surface of the circular disc portion13afrom interference with the outer case20to keep the important minute clearance .δ.

Additionally, an annular recess26is composed on the upper surface of the outer case20around said containable space21, wherein an annular elastic sealing member24such as O-ring is installed in said annular recess26and has contact with said lower surface of the gas nozzle13so that compressed gas in the gas passage16is sealed.

LIST OF PRIOR ART DOCUMENTS

Patent Documents

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

Although the known arts above describes that the gap between the gas nozzle and the liquid nozzle which mostly influences to the size of the injected particles is easily kept to the desired value by the way that the dimension of the gap depends only on the manufacturing tolerances of a single part5or13, there are other factors to influence the value of the gap δ besides that.

As the values are shown in the practical example, the dimensions of parts to compose the nozzle and that of the gap δ are small, the contact state of the top surface of the extrusions with the lower surface of the circular disc portion is important, and it is necessary to take careful attention, in production and assembling. However, influence by manufacturing error is not avoided.

As shown inFIG. 9in detail, geometrical elements to define a top surface of the extrusions of said liquid nozzle5are eight points (points1˜8) and four lines (line1˜4), so that the location of the liquid nozzle in the assembly state is defined by which of these geometrical elements contacts the lower surface of the circular disc of the gas nozzle.

As a plane is defined by a set of two parallel straight lines by a geometric law, when, inFIG. 10afor instance, the line1and the line2are parallel and the height of them are higher than any other geometric elements, a plane including line1and line2is definitely defined and said plane is stuck to the lower surface of the gas nozzle. However, if there is a difference of heights due to manufacturing error between the point1on the line1and the point3on the line2, the liquid nozzle5is installed inclined and the gas exiting gap becomes asymmetric about the center axis14aof said gas exit14. As the result, a mist is sprayed eccentrically to the center axis14aof said gas exit14.

In another embodiment shown inFIG. 10b, when the line1and the line2are parallel and the height of them are higher than any geometrical element and the height of points1˜4are equal, the liquid nozzle5is installed without inclination. However, although the extrusion formed by points5˜8in the right hand is stuck to the circular upper disc portion13aof the gas nozzle13closely, the extrusion in the right hand have a clearance to the upper disc portion13a. As the result, inflow of the gas flow becomes asymmetrical to the center axis of the gas nozzle and the mist is sprayed eccentrically to the center axis14aof said gas exit14. As shown inFIG. 7, there are many geometrical elements to define a plane, so that the geometrical law is not limited to parallel two straight lines. Since including 3 points (for example, point1and point5and point3) or including a line and a point (for example straight line2and point6) can also define a plane, so that fluctuation in the location of the liquid nozzle by manufacturing error is various.

Accordingly, it is an object of the present invention to provide a two-phase flow nozzle with compensation of variety of location of the liquid nozzle as explained above and make sure to spray correctly.

Solution to the Problems

The above-mentioned problems solved by a two phase flow nozzle of the composition which adds improvement of the following (1)˜(3) to the structure of the patent document 1.

(1) On the upper surface of said liquid nozzle, a plurality of extrusions are provided to form said gas exiting gap between the upper surface of said liquid nozzle and the circular disc portion of said gas nozzle, where said extrusions are formed as an evolution curved surface having outer diameters expanded gradually from a top portion to a bottom portion,

(2) Said liquid nozzle is composed of an upper portion with a larger outer diameter and a lower portion with a smaller outer diameter and an intermediate portion having outer diameters reduced gradually from the upper portion to the lower portion, where a side wall of said lower portion is a tapered surface curved from upper to lower.

(3) An intermediate portion of said liquid nozzle is comprised of an annular offset portion extending inwardly from an outer periphery of the upper portion with a larger diameter with a predetermined length, and a supported portion with a convex spherical surface extending from an inner periphery of said annular offset portion to said lower portion, where, on the other hand, on an upper portion of the liquid nozzle holder, a cylindrical part of said liquid nozzle holder is provided, wherein an upper inner peripheral edge of said cylindrical part constitutes a supporting part of a concave spherical surface which faces and supports said supported portion with the convex spherical surface.

Advantageous Effect of the Invention

It is believed that the two-phase flow nozzle in accordance with present invention will have the advantage to completely eliminate the clearance produced between the gas nozzle and the top portion of the extrusions of the liquid nozzle by a compensation function of the liquid nozzle as described in detail later, and to maintain parallelism with the center axis of gas exit of the gas nozzle and the center axis of liquid spraying exit of the liquid nozzle, whereby the mist injected from the gas nozzle directs correctly to the center axis of the gas exit.

DESCRIPTION OF THE EMBODIMENT

A two-phase flow nozzle of the present invention will be explained referring attached drawings as followings, where names and symbols for the parts or the materials which have same function as the prior art shown inFIG. 7˜FIG. 10are put as same as them in the prior art.1

FIG. 1is a cross sectional side elevation view of the two-phase flow nozzle in this invention, andFIG. 5is an enlarged view of the main parts of it.FIG. 2is a drawing of a liquid nozzle used for the two-phase flow nozzle shown inFIG. 1, where (a) is an oblique drawing of it and (b) is a cross sectional side elevation view of it and (C) is a top view of it.

A two-phase flow nozzle1shown inFIG. 1is composed with a liquid nozzle5and an outer case20. The liquid nozzle5is formed as an evolution curved surface, which is composed with an upper portion with the larger diameter5aand a lower portion with the smaller diameter5band an intermediate portion51having outer diameters reduced gradually from the upper portion to the lower portion, where a side wall of said lower portion is a tapered surface curved from upper to lower. A first liquid passage10is formed by penetrating in the liquid nozzle vertically. In said outer case20. a pillar like containable space21extending vertically from a predetermined position to a upper surface direction to contain the liquid nozzle holder is provided. In this containable space21for the liquid nozzle holder, a nozzle holder7is contained, where the liquid nozzle holder7is provided integrally with or independently from said outer case, and, as shown inFIG. 3, is formed with an evolution body having an evolution axis y, wherein, at the lower portion of the nozzle holder, a bottom part7ahaving an outer diameter to be able to fit adequately to said pillar like containable space21is installed, where an upper portion with a smaller diameter7bwhich is elongated from said bottom part to an intermediate portion of the containable space for the liquid nozzle holder is provided, where an upward portion of said smaller diameter is cylindrical part of said nozzle holder7ewith an open upward end, wherein a liquid nozzle containable space7cin which said bottom part of an outer periphery with a smaller outer diameter is slidably fitted, where a second liquid passage8which is communicated from the bottom of said bottom part7ato the bottom of said containable space7cof the liquid nozzle is provided, wherein a diametrical size of said upper larger part5ais the same as that of said lower small diameter part7b.

Said small diameter part5bof said liquid nozzle5is installed with a slight clearance into the containable space of the liquid nozzle7c.

Said intermediate portion51, as shown inFIG. 2(b)clearly, is comprised of an annular offset portion51aextending inwardly from an outer periphery of the upper portion with a larger diameter with a predetermined length, and a supported portion51bwith a convex spherical surface extending from an inner periphery of said annular offset portion to said lower portion, where, on the other hand, an upper inner peripheral edge7fof the cylindrical part7eof said liquid nozzle holder, as shown inFIG. 3, constitutes a supporting part7fof a concave spherical surface which faces and supports said supported portion with the convex spherical surface, whereby, when said liquid nozzle5is installed into the containable space of the liquid nozzle7c, the convex spherical surface of the supported portion51bcontacts with the concave spherical surface of the supporting part7fof the liquid nozzle holder7, the liquid nozzle5is installed inclination-freely to the center axis of the cylindrical liquid nozzle containable space7c, because both contacting surfaces are spherical.

The convex spherical surface of said supported portion51bis formed as a part of a spherical surface having a central point P on the axis x of the liquid nozzle5located upper than said supported portion51band having a radius Ra, wherein, on the other hand, the concave spherical surface of the supporting part7fis formed as a part of a spherical surface having a central point Q on the axis y of the liquid nozzle holder7located upper than said supporting portion7flocated upper than the supporting portion7fand having a radius Rb, wherein it is desirable that Ra=(0.96˜0.99) Rb.

The reasons why the supported surface of said supported portion51bis a convex spherical surface and the supporting surface of the supporting portion7fis a concave spherical surface are as the followings. The two-phase flow nozzle of the present invention is usually made by plastic molding. In plastic molding, there are problems called “sink mark” and “void”. “Sink mark” is a phenomenon by which a surface of a plastic molding becomes hollow a little by a shrinkage, and on the other hand, the phenomenon an air bubble (hollow) generates inside the molding is called void. There is a case which quality of molding having outward appearance surfaces becomes defective. There is a case which a sink mark is not shown on the surface of the molding article, but an air bubble (hollow) sometimes occurs inside the mold. This is void. Both sink mark and void are a phenomenon which an abnormal shrinkage occurs in cooling and solidification of a plastic molding article. Said sink mark occurs when a thick part and a thin part connect and a difference of thickness is large so that cooling and solidification speed changes each other. When the supported portion is made a concave shape, a thickness change becomes big and it is disadvantageous by a point of a sink mark. Further, because a stress is easy to concentrate at the part where a thick part and a thin part connect, if the connected part is a concave to support a convex, it is easy to receive a pressure and cause a sink mark or breakage even though it is only a assembling state. The two-phase flow nozzle of the present invention is often made with plastics, and this tendency becomes big, particularly when a sink mark or a void is occurred in a product.

A liquid spraying exit10ais composed at a top end of the first liquid passage10of the liquid nozzle5, where three arms22awhich extends to an outside of the radius direction from the upper end part are provided with an equal interval each other in a circumferential direction, where an upper surface22of the upper portion with the larger outer diameter including said arms22ais a plane which crosses perpendicular to said first liquid passage10, wherein on said upper surface of three arms22a, which is a part of said upper surface22, a plurality of extrusions230are provided to form said gas exiting gap between the upper surface of said liquid nozzle and the circular disc portion of said gas nozzle, where said extrusions are formed as an evolution curved surface having outer diameters expanded gradually from a top portion to a bottom portion, especially a semi-spherical surface, and it is desirable that three extrusions are provided together with said arms. To make a rotating moment related to the automatic corrective action most substantial for proper location of liquid nozzle5mentioned later, it is desirable to separate the location of said extrusions from the center axis. To achieve this, it is a way to make the diameter of liquid nozzle5big, but the diameter of outside case20has to be big to maintain the cross-sectional area of the gas passage around the liquid nozzle5, and then, the size of the whole nozzle becomes big. On the contrary, to maintain the location of said extrusions away from the center axis as much as possible, said arms are installed, wherein the diameter of the upper portion with the larger diameter5aof the nozzle5is not changed or rather changed to be smaller.

At an upper portion of said outer case20, a gas nozzle13is provided, where said gas nozzle is composed with a circular disc portion13aand a cylindrical body13belongated from the periphery of said disc portion13ato the lower direction. At the center of said circular disc portion13a, a gas exit14is formed with a center axis which is coaxial with said center axis14a. At the inner wall of said cylindrical body13b, a female screw13cis formed. Further, on the other hand, on the upper outer periphery wall of said outer case20, a male screw20ato mate the female screw13con said gas nozzle13is formed. The center axis14aof said gas exit14is parallel to a center axis10bof said first liquid passage10and the eccentricity of the center axis of said gas exit14with the center axis of said first liquid passage10is desirable to be equal or less than 10% of the diameter of said first liquid passage10. Especially, it is more preferable that both axes are coaxial.

As shown inFIGS. 1, 2 and 5, when said gas nozzle13is fastened to the upper portion of the outer case20by the female screw13cand the male screw20a, the lower surface of the circular disc portion13aof the gas nozzle13is stuck on a extrusion230which is composed on a part of the upper surface22of said liquid nozzle5having a minute height δ, wherein a gas exiting gap17is formed, in a space without said extrusion230, between the upper surface22of said liquid nozzle5and the lower surface of gas nozzle13.

As shown inFIG. 1, a gas passage16to communicate with said gas exiting gap17is formed between the inner wall of said containable space21of said outer case20and the outer wall of upper portion with the larger diameter5aof said liquid nozzle5and between the inner wall of said containable space21of said outer case20and the outer wall of the upper portion with a smaller diameter7bof said nozzle holder7. On the outer periphery of said outer case20, a gas feeding tube15is composed to direct gas to said liquid spraying exit10awith inclination to the center axis of said liquid spraying exit10aand communicates to said gas passage16.

On a lower portion of said outer case20, a liquid feeding passage9is composed integrally with said outer case20. On the center of said liquid feeding passage9, a third liquid passage25is formed and

As shown inFIG. 2, a circular liquid nozzle recess12is composed in the top of the liquid nozzle5around the center axis of the liquid spraying exit10a, where the liquid spraying exit10ais located slightly lower than the top end of the liquid nozzle5. The compressed gas injected through said gas exiting gap17shears the compressed liquid injected from the liquid spraying exit10aand atomizes the liquid, wherein the pressure of the gas in the liquid nozzle recess12becomes negative, so that a part of the gas to atomize, which injects from the gas exit14of the gas nozzle13, produces a turbulent flow around the liquid spraying exit10a. As this turbulent flow crosses the main liquid flow injected from the liquid spraying exit10aand produces turbulent in the liquid, a mist of fine particles can be obtained using gas with low pressure and low rate of discharge.

As shown inFIG. 4, at the beginning of fastening of gas nozzle13, a part or all of three extrusions230with spherical surface is stuck on the lower surface of the circular disc portion13a. As the gas nozzle13is tightened up, a fastening force P is caused at a contact point of the lower surface of the circular disc portion13aand the extrusions. Assuming the distance between the contact point and the center axis of the liquid nozzle containable space7cto be a, a rotating moment Pxa is added to the liquid nozzle5and the nozzle rotates to the direction N. Because the extrusions have three spherical surfaces, the three spherical surfaces contact with the lower surface of the circular disc portion13aand rotation of the liquid nozzle stops due to a geometrical law that three points define a plane. Thus, when the liquid nozzle5is installed, it is fixed at a right position due to the corrective action as previously described and the minute gap δ is assured.

Further, as shown inFIG. 5, when the gas nozzle13is fastened so as the lower surface of the gas nozzle is stuck to the extrusion230, a slight clearance27is made between the upper surface of the outer case20and the lower surface of the circular disc portion13aof the gas nozzle13. Said slight clearance prevents said lower surface of the circular disc portion13afrom interference with the outer case20to keep the important minute clearance δ.

Additionally, an annular recess26is composed on the upper surface of the outer case20around said containable space21, wherein an annular elastic sealing member24such as O-ring is installed in said annular recess26and has contact with said lower surface of the gas nozzle13so that compressed gas in the gas passage16is sealed with elasticity restoring force of the O-ring. It's desirable that this O-ring24is formed out of a rubber resilient material or a resin type resilient material or those compound materials. For example, nitrile rubber, silicone rubber, fluoric rubber, polyurethane rubber and BUCHIRUGOMU, etc. are used as rubber resilient materials.

EXPLANATION OF SYMBOLS

5; Liquid nozzle7; Liquid nozzle holder8; The second liquid passage9; Liquid feeding passage10; The first liquid passage10a; Liquid spraying exit12: Liquid nozzle recess13: Gas nozzle14; Gas exit15; Gas feeding tube16; Gas passage17; Gas exiting gap20; Outer case22; Upper surface of liquid nozzle230; Extrusions with semi-spherical surface24; O-Ring25; The third liquid passage26; ANNULAR recess27; Slight clearance.51: Intermediate portion71: Upper inner peripheral edge