RU187161U1 - Ultrasonic atomizer - Google Patents

Abstract

The proposed utility model relates to ultrasonic devices for aerosol spraying of liquids and can be used in various industries, in particular in spectral analysis, for supplying aerosol to an excitation source of spectra. The technical result is an increase in atomizer life and simplification of its operation. An ultrasonic atomizer containing an ultrasonic generator , with an acoustic waveguide, a unit for spraying liquid with channels for supplying a spray liquid and supplying a conveying gas, the node for spraying liquid is made in the form of a nozzle mounted on the end of the waveguide using a threaded connection, a solid steel tube is inserted into the channel for supplying the sprayed liquid, and the channel for supplying the transporting gas is located in the center of the waveguide perpendicular to the channel for supplying the spraying liquid, the steel pipe inserted into the spray fluid supply channel is divided into two nozzles for supplying fluid and a nozzle for spraying liquids, which are inserted into the tide with a hole in the lower part of the cages, whose diameter is enlarged to 9 mm.

Description

The proposed utility model relates to ultrasonic devices for aerosol spraying of liquids and can be used in various industries, in particular in spectral analysis, for supplying aerosol to the spectral excitation source.

A known ultrasonic atomizer (RF patent for PM No. 146359 B05B 17/06 2014) containing an ultrasonic generator with an acoustic waveguide, a node for spraying liquid with channels for supplying atomized liquid and supplying a transport gas, which is made as a nozzle mounted on the end of the waveguide using a threaded connections, and in the channel for supplying the sprayed liquid located in the center of the waveguide perpendicular to the channel, a solid steel tube is inserted, the spraying end of which is sharpened at an angle, the steel tube is attached on to the waveguide with the help of a shaped sleeve, tightened with a nut and tightened with a torque wrench.

Known atomizer (Application JP N 60-21780 B05B 06/17/1985), containing a node for spraying a liquid with an air stream moving at high speed and an ultrasonic vibrator oscillating node, in the spray there is a horn with a channel to which are connected channels for supplying liquid and air.

Known ultrasonic nebulizer (RF Patent No. 2119390, B05B 06/17/1998) containing an ultrasonic transducer, mechanically connected to a concentrator. At the end of the concentrator, a unit for spraying liquid is installed, made in the form of a mixing chamber with inlet nozzles for supplying liquid and transporting gas and an outlet nozzle for sampling the aerosol of the sprayed liquid, moreover, both the mixing chamber and the outlet nozzle made at the same time are activated by ultrasound.

A known ultrasonic nebulizer (RF patent for PM No. 157338 B05B 06/17/2015) containing an ultrasonic transducer mechanically connected to the concentrator, a node for spraying liquid is installed at the end of the concentrator with inlet nozzles for supplying liquid and transporting gas and an outlet nozzle for sampling aerosol of the sprayed liquid moreover, the node for spraying liquid is made detachable, consisting of two parts - the base with the screw fastening to the hub and the shaped washer, both parts have coordinated concentric the grooves forming the mixing chamber, the inlet and outlet nozzles are installed in the radial holes between the base and the shaped washer and pressed by the washer to the base when it is screwed into the end of the concentrator, while the nozzles are perpendicular to the propagation of ultrasonic vibrations, the free ends of the inlet nozzles are clamped into sliding contacts and the spraying end face of the outlet pipe is made beveled at a certain angle, and its length is chosen so that the beveled end is at the maximum of its own pipe oscillations

The closest analogue is an ultrasonic atomizer (RF Patent ПМ №128521, B05B 06/17/2013) containing an ultrasonic generator, with an acoustic waveguide, a unit for spraying liquid with channels for supplying sprayed liquid and supplying a conveying gas, the unit for spraying liquid is made in the form a nozzle mounted on the waveguide end with a threaded connection, a solid steel tube is inserted into the channel for supplying the sprayed liquid, the spraying end of which is sharpened at an angle, and the channel for supplying the conveying gas located in the center of the waveguide perpendicular to the channel for supplying atomized liquid.

A disadvantage of the known devices is that during operation of the sprayer there are large stresses in the place of attachment of the tubes to the spray nozzle, which lead to their breakage (tubes) after some time. In addition, when operating the atomizer, a compromise must be observed and a frequency close to the resonant one should be chosen, at which oil atomization will still occur, but there will be no destruction (tube breakage).

The objective of the proposed utility model is to create a device that allows, by changing the design of the sprayer, to reduce the voltage ratio at the attachment point of the spraying tube with the working fluid to the maximum voltage in the first antinode.

This object is achieved in that in an ultrasonic atomizer containing an ultrasonic generator with an acoustic waveguide, a node for spraying liquid with channels for supplying sprayed liquid and supplying a transporting gas, the node for spraying liquid is made in the form of a nozzle mounted on the end of the waveguide using a threaded connection , a solid steel tube is inserted into the channel for feeding the sprayed liquid, and the channel for supplying the conveying gas is located in the center of the waveguide perpendicular to the channel for feeding and spraying liquid steel tube inserted into the sprayed liquid supply passage is divided into two branch pipes for supplying the liquid and the nozzle for spraying liquids which are inserted tightly in tide with a hole in the bottom of the nozzle, the diameter of which is increased to 9 mm. A further increase in the size of the tide affects the weight of the spray nozzle and requires an increase in the power of the ultrasonic generator.

The essence of the proposed device is illustrated in the drawing (Fig. 1). A geometric model of the modified mixer and its partition into finite elements are shown in Figure 2.

The developed device is an ultrasonic oscillatory system of Figure 1, made on 4 piezoceramic rings 1 with a thickness of 2 mm, an outer and inner diameter of 10 mm and 5 mm, respectively. On the acoustic waveguide 2 using a threaded connection, a nozzle 3 made of VT3-1 titanium is attached. The steel tube inserted into the spray fluid supply channel is divided into two tubes - supply oil 4 and spray 5, which are pressed into the tide with a hole 6 in the lower part of the nozzle. Along the axis of the ultrasonic vibrating system and the spray nozzle, there is a channel 7 for supplying transporting gas to the spray nozzle 3. The transporting gas (air) is supplied through the nozzle 8. The diameter of the tide with the hole 6 is increased to 9 mm.

The use of two tubes instead of one solid tube makes it easier to operate the sprayer, since it is not necessary to replace the entire tube, but only the sprayer part.

The device operates as follows:

Through pipes 4 and 8, a liquid and a transporting gas (air) are supplied to the mixing nozzle - 3. In the chamber 3, under the influence of ultrasonic vibrations, the liquid turns into a finely dispersed sol and mixes with the flow of conveying air, forming an air-droplet mixture, which is removed from the atomizer with the conveying gas through the nozzle 5. The conveying gas serves to create a directed aerosol flow.

Evaluation of the reliability of the ultrasonic atomizer was carried out in the direction of calculating the ultimate stresses arising from the propagation of ultrasonic vibrations in the nozzles through which the analyzed oil and transporting gas are supplied.

The stresses and strains arising in the design of the mixer were calculated under the harmonic effect on its upper face. The calculations were carried out by the method of superposition of all the found modes to the harmonic response of the structure (Mode Superposition).

The stress distribution in the mixer design was calculated using the Ansys program at a resonance frequency of 19,200 kHz. As expected, the maximum stresses are at the antinodes of the standing wave and at the junction of the spray nozzle with the working fluid of the spray gun.

At the first antinode point, the equivalent Mesis stress (Equivalent (von-Mises) Stress) is ~ 2.1e9Pa, in the second antinode ~ 1.7e9Pa, and at the junction of the spray nozzle with the working fluid ~ 1.6e9Pa. Table 1 shows the data on the maximum number of compression-tension cycles for steel depending on the stress, which are entered into the material properties database in the Ansys program.

Compared with the prototype, in a modified design, the ratio of the voltage at the attachment point of the spray nozzle with the working fluid to the maximum voltage in the first antinode decreases by 10 times.

The resulting data comparing the ultimate stresses are given in table 1.

Table 1. Comparison of ultimate stresses arising in the original design of a mixer with a modified design.

Frequency Hz First voltage antinode Pa Second voltage antinode Pa Mounting point for the nozzle with the working fluid of the voltage mixer Pa Limit the number of cycles to the attachment point Gain Prototype resonance 19 200Hz 19,200 2,1e9 1,7e9 1,6e9 50-100 350 20,000 4,9e7 3,7e7 3,4e7 > 1e6 8 Modified resonance design 22 320Hz 22,320 2,0e10 1,4e10 1,1e9 50-100 2565 22,000 2,7e8 1,8e8 1,8e7 > 1e6 35

Thus, the results obtained allow us to draw the following conclusions:

The stress calculations showed that in this case, the maximum stresses occurring at the attachment point are reduced by 10, therefore, the uptime of the spray gun increases and the resource increases at least 10 times.

  The technical result is an increase in the life of the atomizer and the simplification of its operation.

Claims (1)

An ultrasonic atomizer containing an ultrasonic generator with an acoustic waveguide, a unit for spraying liquid with channels for supplying a spray liquid and supplying a transporting gas, a unit for spraying liquid is made in the form of a nozzle mounted on the end of the waveguide using a threaded connection, inserted into the channel for supplying a spray liquid one-piece steel tube, and the channel for supplying a conveying gas is located in the center of the waveguide perpendicular to the channel for supplying atomized liquid, characterized in that then the steel tube inserted into the spray fluid supply channel is divided into two nozzles for supplying fluid and a nozzle for spraying liquids, which are tightly inserted into the tide with a hole in the lower part of the nozzle, the diameter of which is increased to 9 mm.

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