CN1265610A - Ultrasonic atomization device with liquid circulation pipeline - Google Patents

Abstract

The present invention relates to an ultrasonic device for atomizing a liquid. The device is composed of at least one atomizing unit (1), wherein an ultrasonic transducer (2) oriented approximately upwards is arranged at the bottom of each unit (1), the top of each unit (1) being open (covered by gas), the device being characterized by a liquid bath (3) connected to all units, means for maintaining the liquid in each unit at a minimum liquid level during atomization, a high-frequency power supply connected to each transducer (2), and circulating means (6) for causing the liquid to be atomized to flow through the liquid bath (3), each transducer (2) and then back into the liquid bath (3).

Description

Ultrasonic atomization device with liquid circulation pipeline

field of invention

The present invention relates generally to ultrasonic devices for nebulizing liquids. In particular, the invention relates to an ultrasonic device for atomizing liquids having at least one atomizing unit, characterized in that it has: a liquid reservoir connected to all units; means for maintaining the liquid level in each unit; connected The high-frequency power supply for each transducer; the circulation (acceleration) device that makes the liquid return to the liquid pool from the liquid pool through each transducer.

Background of the invention

Standard ultrasonic devices for nebulizing liquids usually consist of a single nebulizing cell with an upwardly oriented liquid-covered ultrasonic transducer configured at the bottom of the cell and the top of the cell is open (covered by gas). These known devices suffer from a number of operating disadvantages which prevent their use in many ways. These disadvantages arise from the specific operational limitations of the individual components of standard known devices.

First, if an ultrasonic transducer is exposed to air (or gas) during operation, the transducer overheats almost instantaneously. Moving the standard may tilt the liquid level above the transducer, thereby exposing the transducer to air or gas. Creating a sufficiently high liquid column above the transducer helps to solve the device movement problem, but this adversely affects the operating efficiency of the transducer.

Second, the accumulated sediment and impurity coating caused by the environment of the liquid will have an adverse effect on the vibrating surface of the ultrasonic transducer. These coatings generally reduce transducer efficiency and create an insulating layer that eventually causes the transducer to overheat.

Impurities in liquids come from many sources. Usually there are impurities in the liquid from the beginning, and impurities can enter the liquid through the contact of the liquid with air (or gas). Impurities are sometimes the result of interactions between the liquid and device components such as pumps, gaskets, etc. In addition, the interaction process with the transducer (such as ultrasonic action, chemical action or electrolytic action) may also generate impurities. These impurities often clump together, causing a coating (deposit) to build up on the transducer.

Third, the use of multiple transducers in the same atomization unit (to increase atomization speed and output) will result in liquid turbulence acting on the transducers (including destructive galvanic erosion).

The device of the present invention can overcome the above-mentioned disadvantages, so that the equipment can be moved (without the risk of exposing the transducer) and the accumulation of impurities can be prevented.

Additionally, most known nebulizers produce aerosol particle sizes that have a broad statistical distribution curve. This is a disadvantage in applications requiring ultra-accurate delivery systems (eg, drugs, disinfectants, bactericides, etc.). One embodiment of the device of the present invention can in particular produce a very narrow statistical distribution curve with aerosol particle diameters between about 0.5 and 5.0 microns. Summary of the invention

The present invention relates to ultrasonic devices for nebulizing liquids. This device is made up of at least one atomizing unit (wherein, the supersonic transducer that orientation is approximately facing up is arranged at the bottom of each unit, and the top of each unit is open (covered by gas), is characterized in that having: be connected to all units the liquid reservoir; the means for maintaining a minimum liquid level in each unit during operation; the high frequency power supply connected to each transducer; and the reflow of liquid (to be atomized) from the liquid reservoir through each transducer Circulation device back to liquid pool. Detailed description of the invention

Within the scope of this invention, "transducer" means any transducer, mechanical, electrical or electronic component immersed in a liquid, through which vibrations above 800KHz can be induced to generate mist particles, or Atomize immersion liquid, or produce aerosol. Furthermore, within the scope of the present invention, an "upwardly oriented" ultrasonic transducer is related to the main trajectory direction of the generated mist, spray or aerosol. Within the scope of the present invention, "approximately upwards" relates to small angular deviations from the true upwards direction, where the small angles are never zero.

This invention relates to ultrasonic devices for atomizing liquids which are particularly effective for producing very narrow statistical distribution curves, with particle diameters of about 0.5 to 5.0 microns. The device comprises at least one atomizing unit, wherein ultrasonic transducers oriented approximately upward are arranged at the bottom of each unit, and the top of each unit is open (covered by gas).

There may be some benefit in having the transducer configured in an approximately upward orientation rather than in an exact upward orientation. The main benefit relates to the return trajectory of escaping heavy mist particles that do not have enough momentum to remain in the upward (airborne) direction for long, which will return to the liquid surface of the cell. When the transducer is oriented exactly upwards, the return trajectory of the heavy mist particles will return many of the mist particles directly to the liquid surface area where the mist particles were emitted from the transducer. This fallback temporarily affects the emission of new mist particles and thus adversely affects the efficiency of aerosol particle generation (atomization).

When the transducer is in an approximately upward orientation (slightly inclined), the fallback trajectory of heavy fog particles is different from the emission trajectory of these same particles. The efficiency of the transducer thus suffers only a very small loss in relation to the approximately upward tilt angle.

Embodiments of the device of the present invention have from one atomizing unit to about 100 atomizing units. A preferred embodiment of the device of the present invention has about 12 to 36 atomizing units.

Within the scope of the present invention, "pipe" means a pipe, tube, conduit, tunnel, channel, etc.

The feature of the device of the present invention is to have: the liquid pool that is connected with all units with pipe; During atomization, keep the device of minimum liquid level height in each unit; Be connected to the high-frequency power supply of each transducer; A device that circulates liquid through the sump, tubes, and individual transducers.

According to a preferred embodiment of the device according to the invention, the operating frequency range of the power supplied to the transducer is above 800 kHz. This frequency range has been found to be more effective for generating ultra-fine aerosol atomized particles (0.5-5.0 μm in diameter).

The working life of the transducer depends on the degree of reducing the accumulation of impurities and deposits on its vibrating surface. Operational interactions between the transducer and the liquid also cause these impurities and deposits. The main mechanism by which the present invention prevents the formation of a built-up coating (deposition layer) on the transducer surface is to circulate the liquid through the individual transducers (preventing impurities from settling on the transducers).

In a preferred embodiment of the device according to the invention, floating, settled, precipitated or filterable impurities in the liquid are removed in the liquid bath. The choice of which impurities or how many impurities (or precipitates) to remove (and their removal methods) should be operationally determined by the characteristics of the liquid to be atomized.

The physisorption and adhesion properties of liquid-borne impurities (residues) and precipitates strongly depend on the liquid flow rate. In stationary pools (no lateral liquid flow), the methods of reducing solubility, settling and flotation are optimal.

In a preferred embodiment of the device according to the invention, the liquid reservoir is operatively divided into two parts, so that any liquid (flowing through the liquid reservoir from the atomizing unit) flows through both parts, and the flow rate of liquid entering each part is different. The use of two different liquid flow rates improves the impurity removal process and the precipitate removal process because each process can be performed in the most suitable liquid pool section.

To maintain a minimum liquid level in each unit during operation, there are a number of methods available. These methods include the use of liquid level sensors (eg floats, electrodes, etc.) and controllable flow valves that apply make-up liquid to each unit.

According to a preferred embodiment of the device of the present invention, the means for maintaining the minimum liquid level in each cell during atomization consists of a number of cells having a height corrected by the liquid pool (thus the liquid level maintained in the liquid pool forms the predetermined level in the pool) and maintain the level in the sump with an inlet valve controlled by a level sensor (so that a drop in the level of liquid in the sump activates the sensor, which in turn causes the valve to open, thus allowing additional liquid to be added to the pool until the pool level is restored).

Within the scope of the present invention, "correcting the height" involves equalizing the hydrostatic pressure between the sump and the unit. The way to achieve this equality is either to physically adjust the liquid level to the same height, or to use a pump to compensate for the height difference.

According to a preferred embodiment of the device according to the invention, a power source connected to each transducer has a sensor connected to the power source. Only when the sensor detects that the liquid level in the liquid pool is lower than a predetermined height, the sensor will automatically cut off the power supply.

In addition, the power source connected to each transducer also has a sensor connected to the power source. As long as the sensor detects that the angle of the liquid level of the liquid pool exceeds a predetermined range, the sensor will automatically cut off the power supply.

Another component of the preferred embodiment of the apparatus of the present invention is an inert separation cyclone (used to remove aerosol particles having a diameter greater than about 5.0 microns from the generated atomized mist). The cyclone (component) consists of a common mist chamber, an air pump, and an open vertical cylinder or cone at the top. The mist chamber is connected to the top of all atomization units. The air pump is connected to the mist chamber (for continuous High-velocity air (or gas) is sent into and through the mist chamber), and the vertical cylinder or cone is connected to the mist chamber (so that air (or gas) and mist can enter the cylinder or cone tangentially bottom).

The mist particles in the produced mist are operatively carried away from the top of the mist unit by high velocity air (gas). When these mist particles enter the helical path in the cylinder (or cone), the heavier (larger) mist particles collide with the cylinder (or cone) and flow back along the wall of the cyclone (so that the final return to the pool).

The present invention will be described further below with reference to FIGS. 1 to 3 . The drawings are provided merely to illustrate and detail selected embodiments of the invention and are not intended to limit the scope of the invention in any way.

Fig. 1 is the profile cross-sectional view of the liquid circulation path that passes through the partial device of basic type embodiment;

Figure 2 is an outline cross-sectional view of the liquid circulation path through the partial device of the preferred embodiment;

Figure 3 is an outline cross-sectional view of the fluid circulation path through another preferred embodiment portion of the device.

Figure 1 shows an outline cross-sectional view of the liquid circulation path through a part of the device of the basic embodiment. Parts of an ultrasonic device for atomizing liquid are shown, including many atomizing units (1), wherein ultrasonic transducers (2) oriented approximately upward are arranged at the bottom of each unit, and the top of each unit is open (provided by gas covered), the ultrasonic device is characterized by a liquid pool (3) connected to all units by pipes (4) (5) and a pump (6), which is used to circulate the liquid to be atomized through the liquid pool, Tubes and individual transducers.

In operation, liquid is pumped into the liquid distribution pipe (4) from the central region of the pool (where there is a minimum of either floating or settled impurities). The pumped fluid flows to each cell, across the face of each transducer. The kinetic energy of the pumped liquid minimizes sedimentation-type impurities staying in the transducer. These sedimentation-type impurities can be carried away by the flowing liquid stream. The planktonic impurities rise to the liquid surface at the same time.

Determining the liquid level (in each unit) is the outlet of the fluid overflow pipe (5). The overflow fluid carries away both planktonic impurities and those sedimentary impurities that have been carried into the flowing fluid stream. This spilled liquid is returned to the sump to complete the cycle. These impurities tend to collect in the liquid pool rather than in the cell or on the transducer.

Figure 2 shows an outline cross-sectional view of the fluid circulation path through a portion of the apparatus of the preferred embodiment. The figure shows an ultrasonic device for atomizing liquid, which includes many atomizing units (1), wherein the ultrasonic transducers (2) facing upwards are arranged at the bottom of each unit, and the top of each unit is open ( Covered by gas, the device is characterized by a liquid pool (3)(7) and a pump (6), the former connected to all units by pipes (4)(5), and the latter used to circulate the liquid to be atomized, making it Flow through the sump, tubing, and across individual transducers.

Each unit includes a liquid inlet (to prevent backflow) port (8), a surface overflow outlet (9), which directs the pumped fluid against the transducer face, and a bottom outlet (10), which is used for The floating type impurities are discharged, while the bottom outlet is used to discharge the sedimentation type impurities. The diameter of the inlet port (8) is larger than the diameter of the bottom outlet port (10).

The sump is functionally divided into two parts so that any liquid (flowing from the unit through the sump) flows through both parts and so that the velocity of liquid entering each part is different. The pool here is divided into a common pool part (3) and a unit-specific pool part (7).

The unit-specific sump section comprises two inlets which are extensions of the outlets (9)(10) in the unit and an outlet (11) leading to the common sump section. The cell-specific liquid reservoirs function functionally as a means of maintaining the liquid level in each cell at a minimum height during atomization, as can be seen together with the cell inlets (8). For the unit, this minimum liquid level is at the level of the outlet (11). In addition, when new liquid does not enter the unit through the inlet (8), it will cause liquid to flow back into the unit (1) from the pool part (7) through the inlet (10).

Figure 3 shows an outline cross-sectional view of the fluid circulation path through another preferred embodiment portion of the device. The figure shows an ultrasonic device for atomizing a liquid, comprising one of many atomizing cells (1), where the ultrasonic transducer oriented approximately upwards is arranged at the bottom of the cell, and the top of the cell is open (covered by gas) , the device is characterized by a liquid pool (3) (7) and a pump (6), the former connected to all units by pipes (4) (5), while the latter circulates the liquid to be atomized through the liquid pool, pipes and across each transducer.

The unit consists of a liquid inlet (prevention of backflow) (8), a surface overflow outlet (9) and a bottom outlet (10), the inlet (8) directing the pumped liquid against the face of the transducer, the outlet (9) It is used to discharge floating impurities, while the outlet (10) is used to discharge sedimented impurities. The diameter of the inlet (8) is much larger than the diameter of the outlet (10).

The sump is functionally divided into two sections such that any liquid (flowing from the unit through the sump) flows through both sections and so that the velocity of liquid entering each section is different. The liquid pool here is divided into a common liquid pool part (3) and a unit-specific liquid pool part (7).

The unit-specific liquid pool part includes two inlets and two outlets (11) (12), the former is an extension of the outlet (9) (10) in the unit, and the latter leads to the common liquid pool part. Outlet (12) diameter is very little, and this outlet (12) just affects the liquid level height of liquid pool part (7) when the device of the present invention is cut off for a long time, discharges to In the common liquid pool (3).

The upper outlet (11) functions functionally as a means for maintaining the liquid in each unit at a minimum liquid level during nebulization, with similar upper portions of other units (not shown) Together with the outlets, this effect can be seen more, and these similar upper outlets share a common upper overflow wall (13). For the unit, this minimum liquid level is at the level of the outlet (11). The common upper overflow wall surrounds all atomizing units or a part of many atomizing units. All atomizing units sharing a common upper overflow wall can thus be efficiently operated on a common liquid sump whenever an overflow condition occurs in some of these units. No introduction of new liquid in the cell will result in the liquid in the sump section (7) flowing back into the cell via the outlet (10).

Claims (10)

1. An ultrasonic device for atomizing liquid, comprising at least one atomizing unit, wherein the ultrasonic transducers facing upwards are arranged at the bottom of each unit, and the top of each unit is open, the device is characterized in that having: a liquid reservoir connected to all units; means for maintaining the liquid in each unit at a minimum level during atomization; power supplies connected to each transducer; and circulation means for moving the liquid from the liquid to the The outflow from the pool flows across the individual transducers before flowing back into the pool. 2. The device of claim 1, wherein the operating frequency range of the power supply to the transducer is above 800 kHz. 3. The device of claim 1, wherein floating, settled, precipitated or filterable impurities can be removed from the liquid in the liquid bath. 4. The apparatus of claim 1, wherein the liquid pool is divided into two sections such that any liquid flowing through the pool from the unit flows through the two sections and such that said liquid entering each section The flow rate is different. 5. Apparatus as claimed in claim 1, characterized in that the means for maintaining a minimum liquid level in each unit during atomization consists of a number of units having a height corrected by the pool such that The liquid level maintained in the liquid sump forms the predetermined liquid level in the unit, and the liquid level in the liquid sump is maintained by the inlet valve, which is controlled by the liquid level sensor, so that the reduction of the liquid level in the liquid sump will be The sensor is activated, which in turn causes the valve to open, whereby make-up liquid is added until the level of the pool is restored. 6. The device as claimed in claim 1, wherein the power supply connected to each transducer has a sensor connected to the power supply, and as long as the above-mentioned sensor detects that the liquid level in the liquid pool is lower than a predetermined height, the power supply will automatically cut off. 7. The device according to claim 1, characterized in that the power supply connected to each transducer has a sensor connected to the power supply, as long as the sensor detects that the inclination of the liquid level in the liquid pool exceeds a predetermined range, the above-mentioned sensor will make The above-mentioned power supply is automatically cut off. 8. The device according to claim 1, which has 12-36 atomization units. 9. The device of claim 1 having an inert separation cyclone for removing mist particles having a diameter greater than about 5.0 μm in the generated mist, the cyclone comprising: a common mist chamber, At the top of all atomization units; an air pump, connected to the aforementioned mist chamber, for continuously sending high-velocity air into and through the aforementioned mist chamber; an open vertical cylinder or cone at the top, the cylinder or cone The body is connected to the above-mentioned mist chamber, so that the air and mist in the above-mentioned mist chamber can enter the bottom of the cylinder or cone from a tangential direction. 10. An ultrasonic device for nebulizing a liquid substantially as hereinbefore described and exemplified.

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