United States Patent 15
`4,319,155
`(11)
`Nakai et al.
`
`[45] Mar, 9, 1982
`
`[54] NEBULIZATION CONTROL SYSTEM FOR A
`PIEZOELECTRIC ULTRASONIC
`NEBULIZER
`
`[75]
`
`Inventors:
`
`Hideharu Nakai, Nagaokakyo; Isao
`Kai, Kameoka; Hirohito Yamamoto,
`Kyoto, all of Japan
`
`[73] Assignee:
`
`Omroh Tateisi Electronics Co.,
`Kyoto, Japan
`
`[21] Appl. No.: 102,534
`
`[22] Filed:
`
`Dec. 11, 1979
`
`Foreign Application Priority Data
`[30]
`Jan. 9, 1979 [JP]
`Yapan ccecscssecssestseeseeseesseee 54-1836
`
`Hint, C13 cccccsssssccscccseresersersseeceseeseree HO1L 41/08
`[SL]
`[52] U.S. C1. vtecescesessssessessssescesssecees 310/316; 310/317;
`128/200.16; 239/102
`[58] Field of Search................ 310/316, 317; 318/116,
`318/118; 128/200.16; 239/102; 261/DIG. 48,
`81
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`2,453,595 11/1948 Rosenthal
`...............
`310/334 X
`« 310/317 X
`3,387,607
`6/1968 Gauthieretal.
`
`3,490,697.
`1/1970 Best,Jr. .....
`239/102
`
`8/1974 Koeblitz .
`we 310/317
`3,828,357
`2/1975 Denton..
`wee 239/102 X
`3,866,831
`
`1/1977 Romain ......
`«+ 128/200.16 X
`4,001,650
`9/1977 Williams .........:.cssseesseeses 310/317 X
`4,047,992
`Primary Examiner—Mark O. Budd
`Attorney, Agent, or Firm—Wegner & Bretschneider
`[57]
`ABSTRACT
`
`' A nebulization control system for an ultrasonic nebu-
`lizer comprising a variable pulse oscillating circuit, an
`ultrasonic vibrating circuit and an ultrasonic vibratoris
`described. The ultrasonic vibrator is caused to vibrate
`alternatingly between a high level whichis sufficient to
`nebulize a fluid and a low level whichis insufficient to
`nebulize the same. The ratio of duration of the high
`level to the low level and/or the amplitude of vibration
`at the high level is variable. This arrangement permits a
`precise control of nebulization quantity and assists in
`the production ofa fine, uniform mistof fluid.
`
`5 Claims, 3 Drawing Figures
`
`
`
` ULTRSONIC
`FLUID LEVEL
` Q
`DETECTING
`VIBRATING
`
`
`CIRCUIT
`
`CIRCUIT
`
`
` CONSTANT
`
`
`
`OLTAGE POWER)
`CIRCUIT
`
`
`
`
`
`UNITED THERAPEUTICS, EX. 2039
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`Page 1 of 6
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`

`

`U.S. Patent Mar. 9, 1982
`
`Sheet 1 of 2
`
`4,319,155
`
`OPERATION]
`
`INDI CATING
`CIRCUIT
`
`35
`
`r G *
`
`11
`
`
`
`
`
`ULTRSONIC |
`VIBRATING
`CIRCUIT
`
`33
`
`
`
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`
`
`LUID LEVEL
`DETECTING
`CIRCUIT
`
`ARIAcorals
`
`CIRCUIT
`
`DRIVING
`CIRCUIT
`
`
`
`

`

`U.S. Patent Mar. 9, 1982
`
`Sheet 2 of 2
`
`4,319,155
`
`FIG. 3
`
`NEBULIZATION LEVEL
`
`NEBULIZATION LEVEL
`
`MODE-1
`
`MODE-2
`
`MODE-3
`
`HIGH
`
`Low
`
`OFF
`
`OFF
`
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`1
`
`4,319,155
`
`2
`the quantity to be nebulized is small, thereby to produce
`a fine mist of medicamentor thelike.
`It is a further object of the present invention to pro-
`vide a nebulization control system which requires only
`asmall rash current and entails a relatively small power
`consumption for nebulization.
`Essentially speaking, the nebulization control system
`of this invention is such that an ultrasonic vibrator is
`held in partially excitedstate and the oscillation circuit
`output is increased from a non-nebulization level to a
`nebulization level and decreased from thelatter level to
`the former in repetation so as to control the quantity
`and degree of nebulization.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG.1 is a block diagram of the nebulizing control
`system for an ultrasonic nebulizer according to the
`present invention;
`FIG.2 showsa specific circuitry including the ultra-
`sonic vibrating circuit and driving circuit shown in
`FIG.1;
`FIG. 3 shows an output wave form ofthe ultrasonic
`vibrator according to the present invention; and
`FIG. 4 shows another output wave form of the ultra-
`sonic vibrator.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`Referring to FIG.1, an ultrasonic vibrating circuit 32_
`comprises a rectifying circuit 321 which converts an
`a.c. voltage from a power source 34 to a d.c. voltage
`and supplies the latter to a constant voltagecircuit 35,
`anda driving circuit 40 which supplies a high frequency
`oscillating voltage to an ultrasonic vibrator 11.
`The constant voltage circuit 35 supplies the constant
`d.c. voltage to a fluid level detection circuit 36, a vari-
`able pulse generating circuit 33, and the driving circuit
`40.
`Thefluid level detection circuit 36 feeds an operation
`stop signal to the driving circuit 40 or variable pulse
`generating circuit 33 for stopping ultrasonic vibration
`upon detection of the level of the fluid by a detection
`means 37 whenthe levelhas dropped belowa predeter-
`mined level.
`The variable pulse generating circuit 33 continually
`generates pulses, the interval or amplitude of which is
`variable as described later, and supplied said pulses to
`the driving circuit 40 and an operation indicating circuit
`30 for indicating the nebulization condition.
`Driving circuit 40 causes the ultrasonic vibrating
`circuit 32 to generate a high frequency vibrating output
`of relatively large amplitude during the low level inter-
`val of the variable pulse, while it generates an output of
`relatively small amplitude during the highlevel interval
`of variable pulse.
`The high frequency vibrating outputis applied to the
`ultrasonic vibrator 11 whereuponthelatter generates an
`ultrasonic wave whichis available for the nebulization
`of fluid during the low level interval of variable pulse
`but not available for nebulization during high level
`intervalofvariable pulse, although it keeps the vibrator
`constantly energized.
`FIG. 2 is an electric circuitry showing a specific
`connection between the ultrasonic vibrating circuit 32
`and driving circuit 40.
`The ultrasonic vibrating circuit 32 comprises a full-
`wave rectifying circuit 321 for rectifying the a.c.. sup-
`plied from the a.c. power source 34,
`
`NEBULIZATION CONTROL SYSTEM FOR A
`PIEZOELECTRIC ULTRASONIC NEBULIZER
`
`BACKGROUND OF THE INVENTION
`
`5
`
`10
`
`15
`
`25
`
`This invention relates to a nebulization control sys-
`tem for an ultrasonic nebulizer and, more particularly,
`to a new control system, which can be applied to a
`device for nebulizing fluids with an ultrasonic energy,
`for precisely controlling the quantity of nebulization
`whena relatively small quantity of nebulization is re-
`quired.
`Recently, ultrasonic nebulizers for vaporizing fluids
`have been applied to humidifiers for increasing humid-
`ity in rooms, inhalation apparatuses for the treatment of
`respiratory diseases, beauty aids, etc.
`In such ultrasonic nebulizers, especially those for
`inhalation therapy, narcotherapy, and humidity control
`in hospitals, it is required to precisely control the quan-
`tity of vaporization.
`The ultrasonic nebulizer disclosed in U.S. Pat. No.
`3,387,607 comprises essentially a pulse oscillating cir-
`cuit and an electro-acoustic transducer or ultrasonic
`vibrator whichis energized by the outputof the circuit.
`In such a nebulizer, nebulization quantity controlis
`effected by changing the so-called duty factor, in other
`words, changing the cycle of oscillating time period of
`a pulse oscillating circuit or by changing the ratio of
`oscillating time period to non-oscillating time period of 30
`the pulse oscillating circuit so that the ultrasonic vibra-
`tor synchronized with the oscillation generates inter-
`mittantly ultrasonic waves of constant amplitude.
`Since the time delay of nebulization after the begin-
`ning ofultrasonic vibration is approximately 0.4 second,
`the time period of ultrasonic vibration or pulse oscilla-
`tion should be more than 0.4 second.
`The nebulizer of U.S. Pat. No. 3,387,607, which
`changes the cycle of ultrasonic vibrating time period or
`the ratio of ultrasonic vibrating time period to ultra-
`sonic non-vibrating time period with the amplitude of
`vibration being kept constant, has the disadvantage that
`a large rush current is unavoidable because the rapid
`increase and decrease of amplitude are involved be-
`tween zero-level and nebulization-level of vibration
`amplitude.
`Another disadvantage emanating from the rapid
`.change ofoscillation or vibration is that large sized fluid
`particles are produced and, especially when a small
`volume of fluid must be nebulized, scattering of fluid
`droplets is unavoidable and, hence, nebulization of uni-
`form size fluid particles is difficult.
`Moreparticularly, in an inhalation apparatus for an
`inhalation therapy of respiratory tract diseases wherein
`the nebulized fluid medicamentis inhaled, it is required
`to precisely control the nebulization quantity over the
`vast range from a very little quantity to a relatively
`great quantity depending on the condition of the pa-
`tient.
`A further disadvantageis that when the fluid medica-
`ment is of high viscosity, it is not only difficult to obtain
`a fine mist but also impossible to. precisely control the
`nebulization quantity.
`Therefore, a primary object ofthe present invention
`is to provide a nebulization control system for an ultra-
`sonic nebulizer, which provides a constant and accurate
`particle size control over the nebulized fluid even when
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`3
`Connected to output terminals of the full-waverecti-
`fying circuit 321 are a high frequency bypassing capaci-
`tor 322 and a series connection of a coil 323, a power
`transistor 324, and another coil 325. A capacitor 326 is
`connected between the collector of a power transistor
`324 and a groundline. Ultrasonic vibrator 11 and capac-
`itor 327 connected in series are connected between the
`base and collector of the transistor 324, and a capacitor
`328 is connected between the base and the ground line.
`A constant voltage circuit 35 is connected to the
`output terminals of the rectifying circuit 321 through a
`resistor 329, which comprises a Zener diode 351 and a
`smoothing capacitor 352 connected in parallel.
`The driving circuit 40 comprises a resistor 41, a tran-
`sistor 421, and 422 connected in series, which is con-
`nected between the positive line of the constant voltage
`circuit 35 and the base of transistor 324.
`A resistor 43 is connected in paralle] with the transis-
`tor 422. Transistor 421 becomes OFF on reception of a
`detection signal representing a shortage of fluid from
`the fluid level detecting circuit 36 to thereby stop the
`vibration of ultrasonic vibrating circuit 32.
`It is preferable, for enabling a free choice of different
`ultrasonic vibration output levels within the-nebuliza-
`tion range, to connect one end eachof resistors 411, 412,
`and 413 ofdifferent resistance values to the positive line
`of the constant voltage circuit 35 and connect the other
`ends to a selecting switch 44 (see FIGS. 2 and 4).
`i.e.
`FIG. 3 shows the wave-form of output pulses,
`intervals of ultrasonic vibration, from the driving cir-
`cuit 40, wherein a resistor 41 is inserted so as to provide
`a uniform ultrasonic vibration level within the range of
`nebulization.
`The operation of the nebulization control system
`according to the present
`invention will now be de-
`scribed in detail with reference to FIG. 1 through FIG.
`4.
`
`Fluid level detecting circuit 36 holds the transistor
`421 in “ON” condition unless an abnormality is de-
`tected.
`Variable pulse generating circuit 33, which consists
`of a known variable means for changing the duty factor
`of pulses,
`in other words, duration and frequency of
`pulses, feeds pulses of predetermined frequency to the
`base of transistor 422, which is turned on when the level
`of input pulse is low, so that a relatively large input
`current is supplied to the powertransistor 324.
`Ultrasonic vibrating circuit 32 functions as a Colpitts
`oscillating circuit and supplies to the ultrasonic vibrator
`11 an oscillating output of relatively large amplitude,
`during the variable pulse is of low level, so that the
`ultrasonic vibrator 1 generates an ultrasonic vibrating
`output whichis sufficient to nebulize the fluid.
`Whenthevariable pulse from the variable pulse oscil-
`lating circuit 33 attains a high level, the transistor 422 is
`turned off.
`If resistor 43 has not been inserted, no currentis sup-
`plied to the base of transistor 324 and the ultrasonic
`vibrating circuit 32 is not actuated.
`Since resistor 43 is connected to the transistor 422 in
`parallel, a small currentis supplied to the base of power
`transistor 324 throughresistors 329 and 41, the collector
`and emitter of transistor 421, and resistor 43, so that
`ultrasonic vibrator 11 generates an ultrasonic wave of
`relatively small amplitude whichis in the range of non-
`nebulization, for example, one third of the full nebuliza-
`tion amplitude.
`
`30
`
`4
`After this, depending on the output level of the vari-
`able pulse oscillating circuit 32, a relatively large output
`and a relatively small output of ultrasonic vibration are
`generated alternatingly to nebulize the fluid or to keep
`the fluid not to be nebulized.
`Since the ultrasonic vibrator 11 is thus held in con-
`stantly energized state and the vibrator outputis caused
`to vary from a non-nebulization level, which is higher
`than the prior art
`level corresponding to the non-
`excited state of the ultrasonic vibrator, to a nebulization
`level or vice versa in synchronization of the output
`pulse of the pulse generating circuit 33, the amount of
`rush current ts so much reduced, with the result that the
`scattering offluid by a large rush current is prevented
`and a fine uniform mistoffluid particles is produced.
`In the above mentioned embodiment,
`the quantity
`can be nebulization variably controlled by changing the
`duty factor of output pulses from variable pulse gener-
`ating circuit 33.
`FIG.4 shows the wave-formsofultrasonic vibrating
`output which are obtainable as resistors 412 through
`413, in placeof resistor 41, are switched by means of the
`selecting switch 44.
`Resistor 411 hasa relatively large resistance, resistor
`412 has an intermediate resistance, and resistor 413 has
`- a relatively small resistance.
`When resistor 411 has been selected, that is, in Mode-
`1 shownin FIG.4, a relatively small current is supplied
`to the base of powertransistor 324 during the low level
`of variable pulse which turns on the transistor 422, and
`ultrasonic vibrating circuit 32 causes ultrasonic vibrator
`11 to vibrate in a sufficient range to cause nebulization
`of a small quantity of fluid.
`On the other hand, during the high level of variable
`pulse which turns off the transistor 422, a small current,
`whichis defined by the resistance ofresistor 43, is sup-
`plied to the base of powertransistor 324 and the ultra-
`sonic vibrating circuit 32 causes the ultrasonic vibrator
`11 to vibrate in the range of non-nebulization.
`Whenresistor 412 has been selected bythe selecting
`switch 44, i.e. in Mode-2 shown in FIG. 4, during the
`low level of variable pulse, the base current of interme-
`diate value which is sufficient to nebulize the fluid is
`supplied to the power transistor 324, while, during the
`high level of variable pulse, a small base current which
`is insufficient
`to nebulize the fluid is supplied to the
`transistor 324, so that
`the ultrasonic vibration of an
`intermediate level for the nebulization of an intermedi-
`ate quantity is generated.
`Whenresistor 413 has been selected with the select-
`ing switch 44,i.e. in Mode-3 shownin FIG. 4, during
`the low level of variable pulse, a relatively large base
`current which is sufficient to nebulize the fluid is sup-
`plied to the powertransistor 324, while, during the high
`level of variable pulse, a very small current defined by
`the resistance value of resistor 43 is supplied to the
`transistor 324, so that a large quantity of fluid is nebu-
`lized.
`The adoption of such an amplitude variation and a
`60 duty factor changingis desirable for a precise control of
`nebulization.
`What ts claimedis:
`1. A nebulization control system for an ultrasonic
`nebulizer, comprising:
`a variable pulse oscillating circuit,
`an ultrasonic vibrating circuit, the vibration ampli-
`tude of which depends upon the output of said
`variable pulse oscillating circuit, and
`
`4,319,155
`
`25
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`35
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`40
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`45
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`5
`an ultrasonic vibrator which is energized by the out-
`put of said ultrasonic vibrating circuit,
`wherein said ultrasonic vibrator is caused to vibrate
`in alternation between a predetermined high ampli-
`tude level whichis sufficient to nebulize fluid and a
`predetermined low amplitude level, greater than
`zero, whichis at or near the maximum amplitude at
`which nebulization will not take place.
`2. A nebulization control system for an ultrasonic
`nebulizer according to claim 1, wherein the ratio of the
`duration of vibration of said high level to that of said
`low level is variable.
`
`6
`3. A nebulization control system for an ultrasonic
`nebulizer according to claim 1, wherein the amplitude
`ofvibration at said high level is variable.
`4. A nebulization control system for an ultrasonic
`nebulizer according to claims 1, 2, or 3, wherein the
`difference in amplitude between the high level and the
`low level is chosen to produce a predetermined nebuli-
`zation quantity.
`5. A nebulization control system for an ultrasonic
`nebulizer according to claims 1, 2, or 3, wherein the low
`level amplitude is one-third the high level amplitude.
`*
`*
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`¢
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`4,319,155
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