JPS6366269B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an atomization device for atomizing various liquids such as liquid fuels such as kerosene and light oil, water, and chemical solutions. This invention relates to an injection type atomization device that sprays liquid from a nozzle and atomizes the liquid by exciting the liquid with an electric vibrator.

Conventional structure and its problems Conventionally, this type of atomization device was mainly used in the ink jetting device of an inkjet recording device, and the atomization device was designed to be extremely compact and capable of realizing a stable droplet jetting pattern. provided.

FIG. 1 is a sectional view showing the configuration of a typical conventional atomizing device.

In FIG. 1, a nozzle 2 is provided at one end of a liquid chamber 1, and a diaphragm 3 and a piezoelectric vibrator 4 are bonded to each other and provided at the other end. Further, the liquid chamber 1 is connected to a tank 6 through a pipe 5.
When a pulse voltage (alternating current voltage) as shown in FIG. 2 is supplied to the piezoelectric vibrator 4, the diaphragm 3 and the piezoelectric vibrator 4 cause deflection vibration as shown by the broken line in FIG. Therefore, a pressure wave is generated in the liquid chamber 1 in the direction of the arrow in the figure, and a second droplet 7 is generated from the nozzle 2.
Injected according to the voltage shown in the figure. In addition, a volume of liquid equivalent to the injected liquid is automatically sucked up from the pipe 5 by the surface tension of the liquid generated in the nozzle 2, so the liquid can be replenished into the liquid chamber 1 without the need for a pump or the like. .

However, filling the liquid chamber 1 with liquid is extremely troublesome. That is, as shown in Figure 1,
An exhaust port 8 is provided in a part of the liquid chamber 1, and the liquid in the tank 6 is pressurized and forced into the liquid chamber 1, causing it to overflow from the nozzle 2 and the exhaust port 8. After that, the liquid is closed with a screw 9, and the The situation shown in Figure 1 was achieved.

As described above, the work of filling the liquid chamber 1 with liquid was extremely troublesome, and it was difficult to automate this work. Therefore, as shown in Fig. 1, the liquid chamber 1 is often stored with liquid filled in it for a long period of time, which has the disadvantage that the liquid in the liquid chamber is likely to deteriorate and the nozzle 2 is easily clogged. Was.

Furthermore, if air bubbles are generated in the liquid chamber 1 due to cavitation, or if the body 10 receives a mechanical shock and air enters the nozzle 2, the pressure wave caused by the vibration of the piezoelectric vibrator 4 is caused by the air bubbles. This has the disadvantage that the liquid is absorbed by the liquid, making it impossible to eject droplets from the nozzle 2.

Due to these drawbacks, conventional atomizing devices are extremely difficult to use, and can only be put to practical use in special applications such as inkjet recording devices, and are extremely lacking in versatility.

OBJECTS OF THE INVENTION The present invention aims to provide an atomization device that eliminates the above-mentioned conventional drawbacks.

The first purpose is to make it extremely easy to fill with liquid.
Therefore, it is an object of the present invention to provide an atomizing device that can easily realize automation from the liquid filling process.

The second purpose is that cavitation bubbles can be easily and automatically discharged, ensuring extremely stable atomization operation, and therefore making it possible to atomize various liquids. The object of the present invention is to provide a highly versatile atomization device.

Configuration of the Invention In order to achieve the above object, the present invention has the configuration described below.

That is, a pressurized chamber to be filled with liquid;
a nozzle provided to face the pressurizing chamber, an electric vibrator that vibrates the liquid in the pressurizing chamber and sprays it from the nozzle, and a liquid that controls the liquid level to be approximately constant at a position lower than the nozzle. surface control means, negative pressure generation means for generating negative pressure for sucking up and filling the pressurized chamber with liquid, and a supply connecting the pressurized chamber to each of the liquid level control means and the negative pressure generation means. and an exhaust pipe, the height from the liquid level to the upper end of the pressurizing chamber is h, the density of the liquid is ρ,
When the amount of spray per unit time is Q, the negative pressure is -P, and the flow path resistance of the supply pipe is γ, it is configured so that |-P|≧|h・ρ|+|γ・Q| By controlling the negative pressure -P, the pressurized chamber can be freely filled with liquid, and the pressurized chamber is always kept filled with liquid during the spraying operation, preventing cavitation. Air bubbles can be stably discharged from the pressurized chamber to ensure good spraying operation.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view showing the configuration of an atomizing device according to an embodiment of the present invention.

In FIG. 3, the atomizing unit 10 is attached to a wall surface 11 with screws 12. The atomizing unit 10 includes a body 14 having a cylindrical pressurizing chamber 13 with a diameter of 5 to 15 mm and a depth of 1 to 5 mm inside, and a body 14 with a diameter in the center.
A plurality of nozzles 15 of 30 μm to 100 μm are provided,
It is composed of a nozzle plate 16 having a thickness of 30 μm to 100 μm, and a disk-shaped piezoelectric vibrator 18 having a circular opening 17 in the center, an outer diameter of 5 to 15 mm, and a thickness of 0.5 to 2 mm. They are glued together to form the structure shown in the figure. The pressurized chamber 13 is provided with an exhaust port 19 and a supply port 20 above and below, and an exhaust pipe 21
and is connected to the supply pipe 22. Supply pipe 22
is connected to the leveler 23 and forms a supply system for the liquid 24. The leveler 23 has a float 2 inside.
5, the opening degree of the needle valve 28 is adjusted via a connecting rod 27 supported by a strut 26, and the leveler 2
The amount of liquid flowing in from the inlet 29 of No. 3 is adjusted. Therefore, the liquid level A in the leveler 23 is controlled to be substantially constant and is maintained at a position lower than the nozzle 15 as shown in the figure. Due to the liquid level height control action of the leveler 23, the liquid level B in the supply pipe 22 also becomes the same height as the liquid level A as shown in the figure when the atomization operation is stopped, and there is no liquid in the pressurizing chamber 13. It is empty. Therefore, the liquid will not overflow from the nozzle 15 to the outside, and the nozzle 15 will not become clogged due to deterioration of the liquid. If you want to store it for a longer period of time without atomizing, use Leveler 23.
Since it is easy to completely remove the liquid, including the liquid, it is also easy to handle for long-term storage.

Next, the atomization operation including the process of filling the pressurized chamber 13 with liquid will be explained.

30 is a blower, and its intake path 31 includes:
An orifice 32 is provided. Then, the exhaust pipe 2 is connected to the negative pressure generating section 33 on the downstream side of the orifice 32.
1 is connected. When the blower 30 is started, the pressure P ₃₃ in the negative pressure generating section 33 gradually rises with a certain time constant due to the inertia of the blower 30, as shown in FIG. ₃₃
=-P= _-40mmH2O is reached. This pressure P ₃₃ =-
P=-40 mmH ₂ O is transmitted to the supply pipe 22 via the exhaust pipe 21 and the pressurizing chamber 13 . At this time, some air flows in from the nozzle 15, but since the nozzle 15 is small, a negative pressure of approximately the same level as P ₃₃ is applied to the liquid level B, and the negative pressure of P ₃₃ as shown in Fig. 4 is applied to the liquid level B. As the size increases, the liquid level B rises,
They are balanced at the liquid level C.

This balance condition is P ₃₃ =-P=-h ₁ ·ρ, where h ₁ is the difference in height between liquid level B and liquid level C, and ρ is the density of the liquid. Therefore, h ₁ when the liquid is kerosene is h ₁ = 40 mm/0.8 = 50 mm (ρ≒0.8 g/cm ³ ).

In this way, the pressurized chamber 13 is filled with liquid,
This can be done extremely easily by simply operating the blower 30, which is a means for generating negative pressure -P, and
Since the liquid level C is higher than the pressurized chamber 13,
The air within the pressurizing chamber 13 rises due to its buoyancy and is automatically exhausted from the exhaust pipe 21, thereby preventing air bubbles from remaining within the pressurizing chamber 13.

Also, the operation of the blower 30 is stopped, and the negative pressure -P
By simply setting =0 mmH ₂ O, the liquid level C drops to the position B, and the liquid can be easily drained from the pressurizing chamber 13 to make it empty.

After the blower 30 is started and the liquid is filled in the pressurized chamber 13, an AC voltage as shown in FIG. Supplied.

The piezoelectric vibrator 18 is connected to the nozzle plate 1 in FIG.
Electrodes (not shown) are provided on the adhesive surface with 6 and on the opposing surfaces (left and right surfaces in the same figure), and in response to the supply of alternating current voltage as shown in FIG. 5 a, b, or c. As a result, expansion and contraction strain occurs in the diametrical direction as shown by the arrows in FIG. This expansion/contraction strain is converted into flexural vibration because the piezoelectric vibrator 18 is bonded to the nozzle plate 16 to form an asymmetric bimorph vibrator. Therefore, the bimorph vibrating body of the nozzle plate 16 and the piezoelectric vibrator 18 performs disk deflection vibration with the outer periphery of the pressurizing chamber 13 as a fixed end, as shown by the broken line in FIG. As a result, the nozzle 15 is greatly vibrated in its axial direction (left-right direction in FIG. 3), and the pressurizing chamber 13
The liquid inside is accelerated and jetted due to the acceleration caused by this vibration, and flies as uniform droplets 34 of small diameter as shown in FIG.

The size of this droplet 34 is determined by the diameter of the nozzle 15 and the magnitude and frequency of the voltage supplied to the piezoelectric vibrator 18, so FIGS.
By controlling the timing of the supply voltage, the average amount of droplets of uniform diameter generated per unit time can be freely controlled.

When the spray amount per unit time is Q (cc/sec), the following phenomenon occurs.

That is, since droplets 34 are ejected from the nozzle 15 from the leveler 23 via the pressurizing chamber 13, Q amount of liquid flows through this channel per unit time. Therefore, if the flow path resistance of the flow path during this period is expressed as a pressure loss with respect to the flow rate, and is γ (mmH ₂ O/cc/sec), a pressure loss of ΔP=γ·Q (mmH ₂ O) occurs.

This pressure loss ΔP causes the liquid level C to drop by Δh and become the liquid level C', as shown in FIG.

If this liquid level C' further decreases, the pressure chamber 13
If it falls to a position lower than the upper end 35, the inside of the pressurizing chamber 13 is no longer filled with liquid, and the air bubbles 36 inside the pressurizing chamber 13 generated by cavitation etc. are removed from the pressurizing chamber 13. Therefore, the gas cannot be smoothly discharged into the exhaust pipe 21. In other words, since air remains in the pressurizing chamber 13 and comes into contact with a part of the nozzle plate 16,
It becomes impossible to maintain stable spraying operation.

However, if the liquid level C' is maintained at least higher than the upper end 35 of the pressurizing chamber, the bubbles 36 will be naturally discharged due to their buoyancy, smoothly flowing into the exhaust pipe 21 as shown in Figure 3. Because it will be
It is possible to continue to maintain a stable spray state.

These conditions are particularly important when the liquid contains a large amount of dissolved air, since the generation of cavitation bubbles is unavoidable. This is an essential condition to ensure stable vibration. In order to satisfy this condition, from the liquid level A to the upper end of the pressurizing chamber 13, as is clear from the above explanation,
When the height up to 5 is h, it is necessary to satisfy the following relationship: |-P|≧|ρ・h|+|γ・Q|

It is important to configure the leveler 23, the atomizing section 10, the blower 30 (negative pressure generating means), the supply pipe 22, and the exhaust pipe 21 so as to satisfy this condition.

For example, -P= _-40mmH2O , ρ=0.8g/ ^cm3 , γ
= 50mmH ₂ O/cc/sec, Q = 0.3cc/sec, h must satisfy 40≧0.8・h+50×0.3, and the electrified part 10 must be set so that h≦31.3mm. Therefore, it is necessary to establish a height relationship between the height and the leveler 23.

With this configuration, it is possible to very easily fill the pressurizing chamber 13 with liquid and remove the liquid, and it is possible to realize automation of startup including the liquid filling process very easily. Further, when the operation is stopped, the pressurizing chamber 13 can be left in an empty state, so that the inconvenience of clogging caused by deterioration of the liquid or the like can be prevented. Furthermore, during the atomization operation, cavitation bubbles that occur in the case of a liquid containing a large amount of air are naturally discharged from the pressurizing chamber 13, and the state in which the pressurizing chamber 13 is filled with liquid is maintained. Since a stable atomization operation can always be guaranteed, it is possible to perform atomization of various liquids.

FIG. 6 is a cross-sectional view of an atomizing device showing another embodiment of the present invention, and the same reference numerals as in FIG. 3 indicate corresponding structures, and the explanation thereof will be omitted.

In the same figure, the nozzle 15 is provided on a protrusion 37 provided at the center of the nozzle plate 16, and a droplet 3
4 is injected radially as shown in the figure.

The negative pressure generating means for sucking up the liquid level B to the liquid level C or C' is constituted by a compressor 38. Further, the liquid level A is controlled to be substantially constant by a liquid level control means 23 comprising a fixed tank 39 and a cartridge tank 40 as shown in the figure.

The liquid level control means can also be constructed of an overflow tank 41 and a pump 43 that pumps liquid from the tank 42 into the overflow tank 41, as shown in FIG. With such a configuration, the control liquid level A can be set higher than the tank 42, and the height of the atomizing section 10 from the tank 42 can be adjusted to the magnitude of the negative pressure generated by the negative pressure generating means. You can make it higher without making it too big.

FIG. 8 is a cross-sectional view showing the structure of a combustion machine to which the atomizing device of the embodiment of the present invention shown in FIG. 3 is applied, and the same reference numerals as in FIG. 3 indicate corresponding structures.
In FIG. 8, the blower 30 that sends combustion air is
It is composed of a motor 44 and a fan 45, and forms a negative pressure generating section 33 downstream of the orifice 32.
Combustion air is sent by a fan 45 in the direction of the arrow in the figure, and into a combustion chamber 46 through a number of nozzles 47. 48 is an exhaust pipe.

Kerosene is sent from a tank (not shown) to the leveler 23 through a pipe 49, sucked up by negative pressure generated by a fan 45, and filled into a pressurized chamber in the atomization section 10. The control unit 50 sends a signal to the piezoelectric vibrator of the atomizing unit 10 as shown in FIG.
An alternating current voltage such as
1 is energized and the sprayed kerosene particles 34 are ignited.

Then, it mixes with the air ejected from the nozzle 47 and undergoes diffuse combustion, forming flames 52 and 53. A heat exchanger 54 uses water as a heat medium, for example.

Further, 55 is a stirring plate, which facilitates diffusion combustion and prevents the flame from becoming long.

In this way, the atomization device of the present invention smoothly discharges cavitation bubbles even when using a liquid containing a large amount of dissolved air, such as kerosene, while filling the pressurized chamber with kerosene and atomizing it only during combustion. It is possible to realize a combustion machine with a simple structure, and it does not require a pump or the like and has a simple combustion mechanism, so kerosene does not deteriorate in the atomization part when not in use. Therefore, it is possible to always perform stable combustion, and it is possible to create an easy-to-use and low-cost combustion machine.

Effects of the Invention As described above, according to the present invention, the nozzle faces the pressurizing chamber and the electric vibrator vibrates the liquid in the pressurizing chamber, and the pressurizing chamber, the negative pressure generating means, and the liquid level are controlled. The means is connected with an exhaust pipe and a supply pipe, and the negative pressure is -P, the height from the liquid level to the top of the pressurizing chamber is h, the density of the liquid is ρ, and the flow path resistance of the supply pipe is When γ is the amount of spray per unit time and Q is the amount of spray per unit time, it is configured so that |−P|≧|h・ρ|+|γ・Q| It is therefore possible to realize an atomization device that can carry out atomization, naturally discharge air bubbles caused by cavitation etc. from a pressurizing chamber, and stably atomize.

Therefore, it is possible to have a configuration in which the liquid in the pressurized chamber is removed when not in use, and the liquid is automatically filled into the pressurized chamber and atomized only when in use, thereby preventing nozzle clogging. It is possible to prevent the deterioration of the liquid in the pressurized chamber, and it is also possible to consistently atomize general liquids containing large amounts of dissolved air, making it extremely easy to use and highly versatile. equipment can be provided.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional atomizing device, Fig. 2 is a driving voltage waveform diagram of the same device, Fig. 3 is a sectional view of an atomizing device showing an embodiment of the present invention, and Fig. 4 is a sectional view of the same atomizing device. Figures 5a, b, and c are diagrams showing the rise characteristics of the negative pressure generated by the blower (negative pressure generating means) of the atomizer at startup, and Figures 5a, b, and c are drive voltage waveform diagrams corresponding to the average atomization amount of the atomizer. 6 is a sectional view of an atomizing device showing another embodiment of the present invention, FIG. 7 is a sectional view showing another configuration of the liquid level control means of the same atomizing device, and FIG. 8 is a sectional view of the atomizing device shown in FIG. 3. FIG. 13... Pressurized chamber, 15... Nozzle, 18... Electric vibrator, 21... Exhaust pipe, 22... Supply pipe,
23...Liquid level control means (leveler), 25...Float,
30...Negative pressure generating means (air blower).

Claims (1)

[Scope of Claims] 1 A pressurizing chamber, a nozzle facing the pressurizing chamber, an electric vibrator that vibrates the liquid in the pressurizing chamber and spraying it from the nozzle, and a liquid level located at a position lower than the nozzle. a liquid level control means for controlling the pressure to be substantially constant, a negative pressure generation means for generating negative pressure, and a supply pipe and an exhaust pipe that respectively connect the liquid level control means and the negative pressure generation means to the pressurizing chamber. The height from the liquid level to the upper end of the pressurizing chamber is h, the density of the liquid is ρ, the amount of spray per unit time is Q, and the negative pressure is -
P, when the flow path resistance of the supply pipe is γ, |−
An atomizing device configured so that P|≧|h・ρ|+|γ・Q|. 2. The atomization device according to claim 1, wherein the negative pressure generating means is a blower. 3. The atomization device according to claim 1, wherein the liquid level control means is a leveler having a float. 4. The atomization device according to claim 1, wherein the liquid level control means is composed of a cartridge tank and a fixed tank. 5. The atomization device according to claim 1, wherein the liquid level control means is comprised of an overflow tank and a pumping pump.