Two-phase flow nozzle

Abstract

A two-phase flow nozzle, having limited dimensions of main parts relating to size of atomized particle and having practical means to assure the important dimension 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 a gas nozzle having a gas exit, wherein said gap is formed by sticking the minute extrusion composed integrally on said liquid nozzle with said gas nozzle or sticking the minute extrusion composed integrally on said gas nozzle with said liquid nozzle.

Claims

1. A two-phase fluid spraying nozzle comprising; a liquid nozzle having a first liquid passage and a liquid spraying exit having a diameter of A and injecting liquid from the first liquid passage, a circular recess having a diameter of B and which is provided at a top end of said liquid nozzle so that the liquid spraying exit comes to be lower than a top surface of said liquid nozzle, and a gas nozzle having a plurality of gas exiting gaps at a gas exit feeding compressed gas for atomizing the compressed gas from the gas exit; wherein A is smaller than B; wherein a plurality of extrusions, which are composed integrally on an upper surface at an end of said liquid nozzle and each of the plurality of extrusions having a pair of sidewalls, contact the lower surface of said gas nozzle, and are circumferentially spaced from each other so that said gas exiting gaps of the gas exit are formed by the upper surface of the liquid nozzle, the lower surface of the gas nozzle, and respective sidewalls of the plurality of extrusions; wherein the compressed gas exiting from said gas exiting gaps flows into the circular recess and becomes turbulent flow which thereby impinges on a liquid flow from the liquid spraying exit so as to make a mist therefrom; wherein the top surface of the liquid nozzle and the plurality of extrusions are perpendicular with the first liquid passage.

2. The two-phase nozzle as set forth in claim 1, further comprising; a nozzle holder provided with a containable space having a cylindrical inner hole to contain the liquid nozzle at a lower portion of the liquid nozzle having a cylindrical outer periphery, the nozzle holder having a bottom part having a cylindrical outer periphery, and an upper part extending upwardly from said bottom part with a cylindrical outer periphery with smaller outer diameter than the outer diameter of the bottom part, an outer case provided with a cylindrical inner hole for an assembled body of said liquid nozzle and said nozzle holder to install the assembled body, a gas passage composed between the cylindrical inner hole of said outer case and the cylindrical outer periphery of said upper part of said nozzle holder and communicated with said gas exiting gaps, a gas feeding tube communicated with said gas passage, a second liquid passage composed in said nozzle holder and communicated with said first liquid passage, and a liquid feeding passage having a third liquid passage which communicates with said second liquid passage; wherein said gas nozzle is fastened to said outer case making a space between the outer case, and the compressed gas is sealed to prevent from leakage to the outside by filling an elastic material in said space.

3. The two-phase nozzle as set forth in claim 2, wherein the cylindrical outer periphery of said lower portion of said liquid nozzle is slideably fitted to the inner hole of said containable space of said nozzle holder and the cylindrical outer periphery of said bottom part of said nozzle holder is slideably fitted to the inner hole of the outer case.

4. The two-phase nozzle as set forth in claim 3, wherein said gas exit is shaped to be a cylinder or a truncated cone having an exit diameter larger than an inlet diameter, said first liquid passage is shaped to be a cylinder, wherein said gas exit is provided with eccentricity of the center axis of the gas exit to the center axis of said first liquid passage to be equal to or less than 10% of the diameter of said first liquid passage, and wherein said gas feeding tube is inclined to the center axis of said liquid nozzle toward the direction of liquid injection.

5. The two-phase nozzle as set forth in claim 2, wherein said gas exit is shaped to be a cylinder or a truncated cone having an exit diameter larger than an inlet diameter, said first liquid passage is shaped to be a cylinder, wherein said gas exit is provided with eccentricity of the center axis of the gas exit to the center axis of said first liquid passage to be equal to or less than 10% of the diameter of said first liquid passage, and wherein said gas feeding tube is inclined to the center axis of said liquid nozzle toward the direction of liquid injection.

6. The two-phase nozzle as set forth in claim 2, wherein said elastic material is an O-ring, which is installed between the lower surface of the gas nozzle and the surface of the outer case opposite to it.

7. The two-phase nozzle as set forth in claim 1, wherein said gas exit is shaped to be a cylinder or a truncated cone having an exit diameter larger than an inlet diameter, said first liquid passage is shaped to be a cylinder, wherein said gas exit is provided with eccentricity of the center axis of the gas exit to the center axis of said first liquid passage to be equal to or less than 10% of the diameter of said first liquid passage, and wherein said gas feeding tube is inclined to the center axis of said liquid nozzle toward the direction of liquid injection.

8. The two-phase nozzle as set forth in claim 1, where C is diameter of inlet of said gas exit, where D is the depth of said recess, and where is the height of the plurality of extrusions which is composed integrally on the upper surface of said liquid nozzle or composed integrally on the surface of said gas nozzle, wherein C/A=1.251.55, wherein B/C=1.252 and/or D/A=0.21.0, and wherein /A=0.080.15.

9. The two-phase nozzle as set forth in claim 1, wherein said liquid nozzle is made of plastics or sintered alloy or metals and said plurality of extrusions are made with molding process of plastics or sintering process of powder metals or machining process of metals.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cross sectional side elevation view of the two-phase flow nozzle.

(2) FIG. 2 is a cross sectional side elevation view of the two-phase flow nozzle shown in FIG. 1 showing the main parts enlarged.

(3) FIG. 3(a) is an oblique drawing of the two-phase flow nozzle shown in FIG. 1 and FIG. 3(b) is a cross sectional side elevation view of it.

(4) FIG. 4 is a cross sectional side elevation view of another embodiment of two-phase fluid nozzle in this invention.

(5) FIG. 5 is a cross sectional side elevation view of a conventional two-phase flow nozzle.

DESCRIPTION OF THE EMBODIMENT

(6) FIG. 1 is a cross sectional side elevation view of the two-phase flow nozzle of the present invention. FIG. 2 is a partial enlarged view of FIG. 1. A two-phase flow nozzle 1 is composed with a liquid nozzle 5, a nozzle holder 7, a gas nozzle 13 and outer case 20. FIG. 3 is an enlarged view of said liquid nozzle 5. As shown in FIG. 3, said liquid nozzle 5 is composed with an upper large diameter part 5a, a lower small diameter part 5b and a first liquid passage 10 formed by penetrating the liquid nozzle vertically.

(7) Said nozzle holder 7 is composed with a bottom part 7a, small diameter part 7b which is elongated from said bottom part 7a, a containable space for the liquid nozzle 7c having a cylindrical hole which is located at said small diameter part 7b, a second liquid passage 8 which is communicated from the bottom of said bottom part 7a to the bottom of said containable space 7c of the liquid nozzle. It is desirable that a diametrical size of said upper larger part 5a is the same as that of said lower small diameter part 7b. Said small diameter part 5b of said liquid nozzle 5 is installed with a slight clearance into the containable space for the liquid nozzle 7c. At an upper end of said first liquid passage 10, a liquid splaying exit 10a is composed. As illustrated in FIGS. 2 and 3, an upper surface 22 of the liquid nozzle 5 is a plane which is perpendicular to said first liquid passage 10. On some parts of said upper surface 22, extrusions 23, having a minute height with an object described later, are composed.

(8) Said gas nozzle 13 is composed with a circular upper plate 13a and a cylindrical body 13b elongated from the periphery of said upper plate 13a to the lower direction. At the center of said upper plate 13a, a gas exit 14 is formed. At the inner wall of said cylindrical body 13b, a female screw 13c is formed. The eccentricity of the center axis of said gas exit 14 with the center axis of said first liquid passage 10 is desirable to be equal or less than 10% of the diameter of said first liquid passage 10. Especially, it is more preferable that both axes are coaxial.

(9) A storage space of assembled body 21 having a cylindrical hole is composed in said outer case 20 to contain an assembled body of said nozzle holder 7 and said liquid nozzle 5. The bottom part 7a, having larger diameter, of said nozzle holder 7 is installed into said storage space of assembled body 21 with a slight clearance. Further, on the upper outer periphery wall of said outer case 20, a male screw 20a to mate the female screw 13c on said gas nozzle 13 is formed.

(10) When said gas nozzle 13 is fastened to the upper portion of the outer case 20 by the female screw 13a and the male screw 20a, the lower surface of the circular upper plate 13a is stuck on a extrusion 23 which is composed on a part of the upper surface 22 of said liquid nozzle 5 having a minute height 6, wherein a gap of the gas exit 17 is formed, in a space without said extrusion 23, between the upper surface 22 of said liquid nozzle 5 and the lower surface of gas nozzle 13.

(11) A gas passage 16 to communicate with said gap of the gas exit 17 is formed between the inner wall of said storage space of assembled body 21 of said outer case 20 and the outer wall of the upper large diameter part 5a and between the inner wall of said storage space of assembled body 21 of said outer case 20 and the outer wall of the small diameter part 7b of said nozzle holder 7.

(12) On the outer periphery of said outer case 20, a gas feeding tube 15 is composed to direct gas to said liquid exit 10a with inclination to the center axis of said liquid exit 10a and communicates to said gas passage 16.

(13) On the lower portion of said outer case 20, a liquid feeding passage 9 is composed integrally with said outer case 20. On the center of said liquid feeding passage 9, a third liquid passage 25 is formed and communicates to said second liquid passage 8.

(14) As best illustrated in FIG. 2, a circular liquid nozzle recess 12 is composed at a top end of said liquid nozzle 5 coaxially with said liquid exit 10a where said liquid exit 10a is located to be slightly lower than the top end of the liquid nozzle 5.

(15) The compressed gas injected through said gap of the gas exit 17 shears the compressed liquid injected from the liquid exit 10a and atomizes the liquid. As described by said known art in detail, the pressure of the gas in the liquid nozzle recess 12 becomes negative, so that a part of the gas to atomize, which injects from the gas exit 14 of the gas nozzle 13, produces a turbulent flow around the liquid exit 10a. As this turbulent flow crosses the main liquid flow injected from the liquid exit 10a and produces turbulent in the liquid, a mist of fine particles can be obtained using gas with low pressure and low rate of discharge.

(16) For instance, in case of that the liquid is water and the gas is air, the diameter of first liquid passage 10 (liquid exit 10a): A=0.6 mm, the water pressure is 100 kPa, gas pressure is 90 kPa, the diameter of the liquid nozzle recess 12: B=1.2 mm, the depth of the liquid nozzle recess 12: D=0.6 mm, the diameter of the gas nozzle 13: C=0.9 mm, =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 1030 are obtained.

(17) According to various experiments, the size of atomized particle depends on compressing pressure of liquid and gas, and geometrical figures of passages of liquid and gas, so that the dimensions of main parts composing the nozzle should have relationship each other in order to obtain a desired particle size.

(18) It is found that by experiments, it is desirable that C/A is 1.251.55, B/C is 1.252 and D/A is 0.21.0.

(19) The most important dimension is the height of the fine extrusion 23 to form said gap of the gas exit 17. It is desirable that /A is 0.080.15 but it may be determined in accordance with the object of application. In the best illustrated case, is 0.06 mm.

(20) To assure the dimension of is difficult but is absolutely necessary. In the present invention, it is easy to assure by specifying shape and arrangement of parts to compose the nozzle without complicated manufacturing method. That is, as described before, because the gas nozzle 13 is fastened by a screw to the outer case 20 so as the lower surface of the circular upper plate 13a is stuck to the extrusion 23 of the liquid nozzle 5, the height of the gap of the gas exit 17, which is the minimum clearance, depends only on accuracy of the height 6 of the extrusion 23. Because the extrusion 23 formed on the liquid nozzle 5 is made by molding process of plastics or machinery process of metals integrated with the liquid nozzle 5, accuracy of the height can be easily secured. It is desirable that said extrusion 23 is composed on the liquid nozzle 5 but it is also preferable to compose the extrusion 23 on the lower surface of the circular upper plate 13a.

(21) Further, when the gas nozzle 13 is fastened so as the inner surface of the gas nozzle is stuck to the extrusion 23, a slight clearance 27 is made between the upper surface of the outer case 20 and the lower surface of the circular upper plate 13a of the gas nozzle 13. Said slight clearance prevents said lower surface of the circular upper plate 13a from interference with the outer case 20 to keep the important minute clearance .

(22) Additionally, a circular recess 26 is composed on the upper surface of the outer case 20 around the storage space of assembled body 21, wherein an elastic material 24 such as O-ring is installed in said cavity 26 and has contact with said lower surface of the gas nozzle 13 so that compressed gas in the gas passage 16 is sealed.

(23) FIG. 4 shows another embodiment of two-phase flow nozzle by this invention, wherein composition of two-phase flow nozzle is the same as shown in FIGS. 1-3 except that the nozzle holder 7 is composed integrally with the outer case 20 by plastic molding process, etc.