JPH04118071A - Ultrasonic atomizer - Google Patents

Abstract

PURPOSE:To facilitate fabrication and assembly and to prevent the accumulation of bubbles due to cavitation by fixing a vibrator phone by both ends of a cylinder through a rubber member and further forming a throttling part in a nozzle formed between the sleeve member and the tip of the cylinder. CONSTITUTION:An annular liq. supply passage 7 is formed between a cylinder 2 and a sleeve 6, and a liq. is supplied to the passage 7 from a liq. supply pipe 8. An atomization part 3a is formed at the tip of a vibrator phone 3, an annular nozzle 7a is formed between the cylinder 2 and the sleeve 6, and a liq. is supplied therefrom to the atomization part 3a and atomized by ultrasonic vibration. The phone 3 is positioned so that the relative position between the atomization part 3a and the nozzle 7a is optimized for atomization and fixed and supported by both ends of the cylinder 2 through oil-resistant rubber members 12 and 13. Since a throttling part 15 is formed in the nozzle 7a, the flow velocity is increased in the nozzle 7a, the bubbles generated are immediately discharged to the outside even at a low flow rate, and dripping and discontinuous atomization are obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention generally relates to liquid substances such as liquid fuels (in this specification, liquid substances are not only liquids such as liquid fuels) but also liquid substances such as liquid fuels that are supplied. (Used to include liquid substances such as cloudy solutions.) Using ultrasonic vibration, it is used to atomize ultrasonic atomizers, particularly (a) automobiles, outboard motors, portable power devices, Ultrasonic atomizers applied to internal combustion engines used in the drive devices of consumer heat pump devices, etc.; (b) fuel injection nozzles for gas turbines; (c) boilers and heating furnaces for industrial, commercial and domestic use; Heating burners, (d) Industrial liquid sprayers, such as drying sprayers for drying liquid materials such as food, pharmaceuticals, agricultural chemicals, fertilizers, etc., temperature and humidity control sprays, baked powder sprayers (ceramic granulation) , a spray coating device, a reaction accelerator, and (e) an ultrasonic atomizer suitable for use in non-industrial liquid sprayers, such as pesticide sprayers, disinfectant sprayers, etc.

[Prior Art] Conventionally, as an ultrasonic atomization device that uses ultrasonic waves to atomize a liquid substance into extremely small droplet size, for example, Japanese Patent Laid-Open No. 1982-
As shown in Publication No. 13B2E12, a vibrator horn is disposed inside a cylinder, a sleeve member is disposed around the outer periphery of the cylinder, and the vibrator horn is inserted from an annular liquid supply path formed between the cylinder and the sleeve member. A method is known in which the liquid is uniformly atomized by supplying liquid to the entire circumference of the atomizing surface at the tip.

Conventionally, in the above method, a fixing flange is formed integrally with the node portion of the vibrator horn, and the flange is fixed and supported on the cylinder.

[Problems to be Solved by the Invention] Theoretically, there is a point in the node portion of the vibration system of the vibrator horn that no power loss occurs even if it is fixed. However, in reality, because the fixing flantz has a width rather than a point, and because the speed of sound differs even with the same material, even if the vibrator horn is manufactured with the same dimensions, each 7-domain part The location will be different. As a result, there is a problem in that vibration occurs in the flange portion, resulting in a corresponding power loss in the vibration system.

Further, there are problems in that the cutting process of the flange requires high precision, which increases the cost, and that the flange needs to be tightened uniformly, resulting in poor assembly performance.

Furthermore, in an atomizer, the relative position of the liquid supply nozzle and the atomizing part at the tip of the vibrator horn is an important factor in atomizing characteristics, but in the case of fixation with a flange, the relative position is fixed. Therefore, there is a problem in that the degree of freedom in adjusting the π conversion characteristic is restricted.

In order to solve these problems, the applicant has
No. 22694 discloses a cylinder, a vibrator horn fixed in the cylinder, an electric/acoustic transducer that imparts ultrasonic vibration to the vibrator horn, and an atomization formed at the tip of the vibrator horn. The present invention has proposed an ultrasonic atomizing device comprising a cylinder section and a sleeve member for supplying liquid to the atomizing section, and the vibrator horn is fixed by rubber members at both ends of the cylinder.

However, when the present inventor conducted various experiments,
It was found that cavitation caused bubbles to accumulate in the nozzle facing the vibrator horn, causing dripping and discontinuous spraying.

The present invention solves the above problems, and is an ultrasonic atomizer that reduces power loss in the vibration system, is easy to manufacture and assemble, and can prevent air bubbles from accumulating due to cavitation. The purpose is to provide

[Means for solving the problem] For this purpose, the ultrasonic atomization device of the present invention includes a cylinder 2,
A vibrator horn 3 fixed in the cylinder 2, an electro-acoustic transducer 4 for imparting ultrasonic vibration to the vibrator horn 3, and an atomizing portion 3a formed at the tip of the vibrator horn 3. , the atomizing section 3 is screwed onto the outer periphery of the cylinder 2.
a sleeve member 6 for supplying liquid, and the vibrator horn 3 is connected to rubber members 12 and 13 at both ends of the cylinder 2.
The nozzle portion 7a formed between the sleeve member 6 and the tip of the cylinder 2 is further provided with a constriction portion 5.

Note that the numbers added to the above configurations are for comparison with the drawings, and the configurations of the present invention are not limited thereby.

[Operation] In the present invention, since the vibrator horn is fixed and supported by rubber members at two locations on the cylinder, the vibrator horn is fixed to the cylinder with flexibility at a position that optimizes the atomization characteristics. It can be supported. In addition, since a constriction part is formed in the nozzle part formed between the sleeve member and the tip of the cylinder, the flow velocity increases in the nozzle part, and even at low flow rates, bubbles generated are immediately discharged to the outside, preventing liquid dripping. Spray discontinuity can be prevented.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial cross-sectional view showing one embodiment of the ultrasonic atomization device of the present invention, and FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG.

As shown in FIGS. 1 and 2, the ultrasonic atomizer 1 includes a cylinder 2, a vibrator horn 3 fixed and supported within the cylinder 2, and an ultrasonic vibration applied to the vibrator horn 3. It is composed of an electric/acoustic transducer element 4 and a sleeve member 6 that is screwed onto the outer periphery of the cylinder 2 at a threaded portion 5 . An annular liquid supply path 7 is provided between the cylinder 2 and the sleeve member 6.
A liquid supply pipe 8 is formed and fixed to the sleeve member 6 by welding.
A liquid is supplied from the liquid supply path 7 to the liquid supply path 7 .

An atomizing section 3a is formed at the tip of the vibrator horn 3. The shape of this atomizing portion 3a is such that a radius of curvature is formed at the tip of a rod shape. Further, an annular nozzle part 7a is formed between the cylinder 2 and the sleeve member 6, and liquid is supplied from the nozzle part 7a to the atomizing part 3a and atomized into fine droplets by ultrasonic vibration.

The vibrator horn 3 is fixed and supported at both ends of the cylinder 2 by oil-resistant rubber members 12 and 13.

When fixing, first place the vibrator horn 3 inside the cylinder 2.
is inserted and positioned using a jig or the like so that their concentricity is adjusted and the relative position of the atomizing part 3a and nozzle part 7a is in the optimum atomizing state, and then liquid rubber is injected into both ends. It is to be fixed in place.

Therefore, machining of the O-ring and the O-ring groove is not required, and dimensional accuracy can be improved and costs can be reduced.

In addition, since the concentricity between the vibrator horn 3 and the cylinder 2 is ensured, the sleeve member 6 is fixed to the cylinder 2 only by the short threaded part 5, and unlike the conventional case, the sleeve member 6 is fixed to the cylinder 2 by the short threaded part 5. There is no need for a fitting part to ensure concentricity between the two, making it possible to shorten the overall length and increase rigidity.

Furthermore, thermal strain caused by welding when fixing the liquid supply pipe 8 to the sleeve member 6 can be reduced.

FIG. 3 shows a method of fixing between the atomizing section side end of the vibrator horn 3 and the cylinder 2 using a rubber member 12. (a) shows a method in which the tip of the cylinder 2 is thickened, and the inner periphery of the tip of the cylinder 2 and the cylinder 2 are thickened. The rubber member 12 is arranged in the thick part, and (b) shows an example in which the tip of the cylinder 2 has a sharp edge.

FIG. 4 shows a method of fixing the end of the vibrator horn 3 opposite to the atomizing part and the cylinder 2 with a rubber member 13.
(a) is an example in which the rear end of the cylinder 2 is at a right angle; (b) is an example in which a step is formed on the inner circumferential side of the rear end of the cylinder 2; (C) is an example in which an inclined surface is formed on the inner circumferential side of the rear end of the cylinder 2. An example is shown below.

Next, features of the present invention will be explained with reference to FIGS. 5 to 7. FIG. 5 is an enlarged cross-sectional view of the nozzle portion to explain the occurrence of cavitation, FIG. 6 is an enlarged cross-sectional view of the nozzle portion showing one embodiment of the present invention, and FIG. 7 is another embodiment of the present invention. An enlarged sectional view of the nozzle part showing the.

As shown in FIG. 5, in a structure in which the tip of the sleeve member 6 is located forward of the tip of the cylinder 2 and the nozzle portion 7a contacts the vibrator horn 3, the nozzle portion 7a contacts the vibrator horn 3. Bubbles due to cavitation accumulate in the area.

In particular, when the liquid flow rate decreases, the flow rate slows down, and the flow rate becomes unstable when the accumulated bubbles exit to the outside.

For this reason, in the present invention, as shown in FIG. 6, a constricted portion 15 is provided integrally or separately on the inner peripheral side of the tip of the sleeve member 6. Further, as shown in FIG. 7, a converging portion 15 is provided at the tip of the cylinder 2, either integrally or separately.

Therefore, since the constriction part 15 is formed in the nozzle part 7a formed between the sleeve member 6 and the tip of the cylinder 2, the flow velocity increases in the nozzle part 7a, and the bubbles generated are immediately discharged to the outside even when the flow rate is low. Therefore, dripping and discontinuous spraying can be prevented.

[Effects of the Invention] As described above, according to the present invention, since the vibrator horn is fixed and supported by the rubber member at the 2w position of the cylinder, the vibrator horn is fixed to the cylinder at a position that optimizes the atomization characteristics.
Compared to the conventional case of rigidly fixing with a flange, the power loss of the vibration system can be reduced to about half, and the cutting and assembly of the vibrator horn can be easily performed.

In addition, since a constriction part is formed in the nozzle part formed between the sleeve member and the tip of the cylinder, the flow velocity increases in the nozzle part, and even at low flow rates, bubbles generated are immediately discharged to the outside, preventing liquid dripping. Spray discontinuity can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing one embodiment of the ultrasonic atomization device of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG.
The figure is an enlarged sectional view showing a method of fixing between the atomizing part side end of the vibrator horn and the cylinder with a rubber member, and Fig. 4 is a rubber member fixed between the end of the vibrator horn on the side opposite to the cherry-shaped part and the cylinder. FIG. 5 is an enlarged sectional view of the nozzle part to explain the occurrence of cavity scene, FIG. 6 is an enlarged sectional view of the nozzle part showing one embodiment of the present invention, FIG. 7 is an enlarged sectional view of a nozzle section showing another embodiment of the present invention. 1... Ultrasonic atomization device, 2... Cylinder, 3...
Vibrator horn, 3a... Atomization section, 4... Electric/acoustic conversion element, 8... Sleeve member, 7... Liquid supply path,
7a... Nozzle part, 12.13... Rubber member, 15
...Aperture section. Applicant: Tonen Corporation Sub-Representative Patent Attorney Hiroki Shirai (7 others) Figure 2 Figure 3 (a) (b) (a) (b) (C)

Claims (1)

[Claims] (1) A cylinder, a vibrator horn fixed in the cylinder, an electric/acoustic transducer that applies ultrasonic vibration to the vibrator horn, and an atomizer formed at the tip of the vibrator horn. , a sleeve member screwed onto the outer periphery of the cylinder to supply liquid to the atomizing section, the vibrator horn being fixed at both ends of the cylinder by rubber members, further comprising a sleeve member and a cylinder An ultrasonic atomization device characterized in that a constriction part is formed in a nozzle part formed between the tips of the ultrasonic atomizer.