US3885902A - Ultrasonic generator and burner - Google Patents

Ultrasonic generator and burner Download PDF

Info

Publication number
US3885902A
US3885902A US381786A US38178673A US3885902A US 3885902 A US3885902 A US 3885902A US 381786 A US381786 A US 381786A US 38178673 A US38178673 A US 38178673A US 3885902 A US3885902 A US 3885902A
Authority
US
United States
Prior art keywords
ultrasonic
liquid fuel
ultrasonic transducer
voltage
power source
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US381786A
Other languages
English (en)
Inventor
Hiroshi Fujieda
Taro Yamamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Application granted granted Critical
Publication of US3885902A publication Critical patent/US3885902A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
    • F23D11/34—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space by ultrasonic means or other kinds of vibrations
    • F23D11/345—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space by ultrasonic means or other kinds of vibrations with vibrating atomiser surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/0207—Driving circuits
    • B06B1/0223—Driving circuits for generating signals continuous in time
    • B06B1/0238—Driving circuits for generating signals continuous in time of a single frequency, e.g. a sine-wave
    • B06B1/0246—Driving circuits for generating signals continuous in time of a single frequency, e.g. a sine-wave with a feedback signal
    • B06B1/0253—Driving circuits for generating signals continuous in time of a single frequency, e.g. a sine-wave with a feedback signal taken directly from the generator circuit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
    • B06B2201/50—Application to a particular transducer type
    • B06B2201/58—Magnetostrictive transducer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
    • B06B2201/70—Specific application
    • B06B2201/77—Atomizers

Definitions

  • magnetostrictive or piezoelectric devices are used to convert electrical oscillation into mechanical oscillation.
  • a horn is attached to an ultrasonic transducer in order to amplify the mechanical oscillation, and is used in ultrasonic welding machines or liquid atomization devices.
  • Ultrasonic liquid atomization devices have been for example used in conjunction with liquid fuel burners because of the advantages to be described hereinafter over liquid fuel atomization method of the type in which liquid fuel is injected through a small orifice under high pressure.
  • a first advantage is that the ultrasonic liquid fuel atomization device can eliminate a motor-driven pump for injecting liquid fuel under high pressure through an orifice because a thin film formed upon an oscillating surface of an ultrasonic transducer may be torn off into atomized particles. Therefore, liquid fuel may be supplied to the oscillating surface by, for example, gravity feed means, so that no pump is required.
  • a second advantage is that the ultrasonic liquid atomization device may use a relatively large diameter nozzle in order to supply liquid to be atomized to the oscillating or atomization surface.
  • liquid fuel must be discharged through a small orifice so that clogging tends to occur very often, and this problem is overcome by the ultrasonic fuel atomization method.
  • a third advantage is that the quantity of atomized liquid fuel may be continuously varied over a wide range from zero to the maximum or vice versa only by controlling the flow rate of liquid fuel to be supplied to the oscillating or atomizing surface as compared with the conventional method in which the quantity of atomized liquid fuel may be varied only over a limited range.
  • a first problem is to drive an ultrasonic transducer at a resonant frequency thereof or at a frequency very close thereto in order to attain high efficiency in operation because the ultrasonic transducer has generally a high Q.
  • Theresonant frequency is generally dependent upon the dimensions, configurations and so on so that when the dimensions of the ultrasonic transducer are varied in response to the temperature change the reso- 'nant frequency is also varied. Therefore the ultrasonic oscillator must drive the ultrasonic transducer at its resonant frequency or at a frequency very close thereto.
  • a second problem is to maintain an optimum amplitude of oscillation in order to obtain desired particles sizes of atomized fuel.
  • the amplitude is increased in excess of an optimum level, the particle size is gradually increased due to cavitation whereas when the amplitude is decreased below a optimum level, no atomization of liquid fuel occurs.
  • a third problem is a provision of means for applying a relatively large transitional input to the ultrasonic transducer when atomization of liquid fuel is started and then applying a steady-state input to the ultrasonic transducer a predetermined time after the start of the atomization. More particularly, when a thin film of liquid fuel is formed upon the atomizing surface and has not atomized yet, greater energy than when liquid fuel film is being atomized is required for atomization. This means that the load of the ultrasonic transducer is greater when the atomization is started so that even when the steady-state input is applied the amplitude of oscillation is less than that in the steady-state.
  • the initial input to the ultrasonic transducer must be increased higher than the input required for the atomization in the steady -state and then returned to the normal input level after the start of the atomization.
  • this requirement is referred to as the hysteresis for the sake of convenience in description.
  • a fourth problem is to provide means for immediately stopping the atomization and simultaneously preventing liquid fuel from being discharged without being atomized when the breakdown of any of the component parts of the ultrasonic liquid fuel atomizing device occurs. Especially when the ultrasonic liquid fuel burners are not provided with such means, the breakdown of the ultrasonic transducer is inevitable.
  • a fifth problem is to increase the amplitude of oscillation of the ultrasonic transducer when the temperature of liquid to be atomized drops because the viscosity of liquid is increased.
  • a sixth problem is to provide means for immediately causing liquid fuel supply control means to interrupt the liquid fuel supply when the breakdown of a motor for driving a blower occurs because the liquid fuel supply control means and the blower are controlled independently of each other in operation. If the supply of liquid fuel to the ultrasonic transducer is not immediately stopped, the atomization of liquid fuel would be continued, but the incomplete combustion inevitably would occur because of the shortage of primary air. Furthermore, not only the ultrasonic transducer but also ignition means would be damaged seriously.
  • a seventh problem is to provide means for discharging liquid fuel oil remaining in fuel supply means after said fuel supply control means such as a solenoid valve is closed so that the remaining liquid fuel which is not atomized may be prevented from being discharged into a combustion chamber or from remaining within a housing of an ultrasonic liquid fuel atomizing device.
  • a first object of the present invention is to provide an ultrasonic liquid atomizing device which may substantially overcome the above problems.
  • a second object of the present invention is to provide an ultrasonic liquid fuel burner utilizing the above ultrasonic liquid atomizing device, thereby satisfying the above demands and overcoming the above problems.
  • the oscillator and arrangement of the types described above are combined in a liquid atomizing device or liquid fuel burner so that reliability and safety in operation may be greatly insured.
  • FIG. 1 is a diagram of an ultrasonic liquid atomizing device according to the present invention
  • FIG. 2 is a diagram of a two-output DC power source, a switching circuit and a control circuit for controlling the switching circuit;
  • FIG. 3 is a diagram illustrating an ultrasonic liquid fuel burner in accordance with the present invention.
  • FIG. 4 is a circuit diagram of a timer incorporated in the burner shown in FIG. 3.
  • FIG. 1 The ultrasonic transducer used in the invention is illustratedin FIG. 1.
  • a magnetostrictive device has a coil 11 mounted on its legs 10a and has its oscillating surface attached to the bottom of a frustoconical horn 12.
  • AC voltage whose frequency is equal to a resonant frequency of the ultrasonic transducer is impressed across the coil 11, its motional admittance becomes maximum, so that the maximum current flows therethrough.
  • the magnetostrictive device 10 may transform the electrical oscillations into the mechanical oscillation with the maximum efficiency, and the amplitude of mechanical oscillation perpendicular to an end surface 13 of the frustoconical horn 12 may be amplified greater than the amplitude of the mechanical oscillations at the bottom surface of the horn 12.
  • the amplification factor is dependent upon the material, configuration, and so on of the horn 12.
  • means for supplying liquid to be atomized to the end surface 13 of the horn 12 is provided.
  • the discharge port of a nozzle 14 is opened at the end surface 13 of the horn 12 and the inlet port thereof is connected to a liquid feed line at the node of the horn 12.
  • An amplifier generally indicated by P comprises a phase shift circuit which in turn comprises a capacitor 40 and a variable resistor 41, and a two-stage amplifier.
  • the first stage of the amplifier comprises a blocking capacitor 42, bias resistors 43, 44 and 46, a bypass capacitor 47 of the resistor 46, a transistor 45, and the primary winding 49 of a coupling transformer 48, and the second stage comprises the secondary windings 50 and 51 of the transformer 48, two transistors 52 and 53 and a blocking capacitor 54 inserted in series in an output circuit.
  • a feedback circuit comprises a current transformer 60 whose primary winding 61 is connected in series to the output circuit of the amplifier circuit, and a resistor 63 inserted in parallel with the secondary winding 62 of the transformer 61. The voltage across the primary winding 61 is fed back to the amplifier circuit P, which forms an oscillator together with the feedback circuit.
  • E is peak voltage equal to one half of DC voltage
  • E m is angular frequency (equal to 2'n'f and t is time)
  • the peak voltages of the odd-number harmonics are l/3, l/5,. and l/(2n-l) of the peak voltage of the fundamental component. Therefore, the admittance of the ultrasonic transducer is low with respect to the frequencies of the high frequency components and the peak voltages of the harmonics are decreased as the order of the harmonics is increased so that the current whose frequency is equal to the resonant frequency f flows through the coil 11. From Eq.
  • the fundamental harmonic component e which determines the mode of operation of the ultrasonic transducer, is given y e, (4/11') (E sin 21rf t) It is seen that the fundamental harmonic component e, is only in proportion to DC power voltage and is not dependent upon admittance of the ultrasonic transducer. Therefore, it serves as a constant voltage source for driving the ultrasonic transducer with a constant voltage. Thus, the constant voltage source is provided simply by alternately switching the transistors 52 and 53. Since the transistors 52 and 53 are used for switching operation, the collector loss may be considerably decreased, and the efficient DC-AC conversion may be attained. As seen from BO.
  • the amplitude of the fundamental harmonic component 2 is dependent only upon the DC voltage source so that the voltage applied across the ultrasonic transducer and hence the level of the driving current may be easily varied by changing the DC source voltage.
  • the current in proportion to the current flowing through the primary winding 61 of the transformer flows through the resistor 63 connected in parallel with the secondary winding 62 thereof, so
  • the damped admittance of the ultrasonic transducer is sufficiently smaller as compared with its motional admittance and the ultrasonic transducer is driven by the constant voltage so that the current flowing through the coil 11 is in proportion to the oscillation of the ultrasonic transducer.
  • the oscillation of the ultrasonic transducer becomes maximum at the resonant frequency f and the current flowing through the coil 11 also becomes maximum.
  • the voltage across the primary winding 61 of the transformer 60 becomes maximum.
  • the voltage across the primary winding 61 is positive-fed back to the phase shift circuit and the output of the phase shift circuit is amplified by the transistor 45, so that the switching action of the transistors 52 and 53 may be continued.
  • the constant of the phase shift circuit is controlled by the variable resistor 41 so that the overall phase shift becomes zero or 360 at f Furthermore, the amplification factor higher than unit is selected. Thus, the automatic oscillation at the resonant frequency f may be attained.
  • the commercial line voltage impressed across a pair of input terminals and 22 is dropped to a suitable voltage by a transformer 22, rectified by a bridge rectifier 23 and smoothed by a smoothing capacitor 24.
  • the voltage across the smoothing capacitor 24 is an input current to a DC voltage regulator which comprises a transistor 34, another transistor 35 for detecting and amplifying error, a zener diode 32 for supplying a reference voltage, bias resistors 31 and 33 and a capacitor 36.
  • the AC voltage across the resistor 63 in the feedback circuit is in proportion to the driving current flowing through the coil 11 and hence the oscillation amplitude of the ultrasonic transducer.
  • This voltage is rectified and smoothed by a rectifier circuit comprising a diode 64, a resistor 65 and a capacitor 66, and is substantially in proportion to the driving current flowing through the coil 11. Therefore, the voltage across the capacitor 66 is in proportion to the oscillation amplitude of ultrasonic transducer and is used to regulate the output voltage of the oscillator so that the oscillation of the ultrasonic transducer may be maintained constant.
  • the voltage across the capacitor 66 is divided by a series circuit comprising a resistor 68 and a variable resistor 67 and then applied to the base ofv the transistor 35,
  • the driving current may be held at a predetermined level.
  • the oscillation of the ultrasonic transducer may be maintained at a predetermined constant level.
  • the mode of operation for controlling the oscillation of the ultrasonic transducer will be described.
  • the driving current is increased so that the AC voltage across the resistor 63 in parallel with the secondary 62 of the transformer 60 will be also increased in proportion.
  • the DC voltage across the capacitor 66 is also increased so that the input to the voltage regulator S is also increased. That is, the voltage between the base and emitter of the transistor 35 is increased whereas the voltage across the collector and emitter thereof is dropped so that the output voltage of the DC voltage regulator S is dropped.
  • the oscillation speed of the ultrasonic transducer is reduced.
  • the above step may be cycled until the speed of oscillation of the ultrasonic transducer is stabilized to a constant speed which corresponds to a voltage predetermined by the variable resistor 67.
  • the speed of oscillation of the ultrasonic transducer becomes lower than a predetermined level, it is restored to a predetermined speed.
  • the speed of the ultrasonic transducer may be always maintained at a predetermined level.
  • the amplitude of oscillation of the ultrasonic transducer is expressed by dividing the speed by the angular frequency, the amplitude may be maintained constant when the angular frequency deviation is negligible.
  • the magnetostrictive device 10 is made of a ferrite, is of the 1r type and oscillates at 28 KHz and the horn 12 is made of an aluminum and is of exponential type
  • the resonant frequency deviation is 500 Hz when the temperature is varied from 20C to +C.
  • the frequency deviation of 500 Hz is negligible since the resonant frequency is almost equal to 28 KHz. Therefore, the amplitude may be also stabilized over the above temperature range.
  • the ultrasonic transducer, the oscillator, the DC voltage regulator and the DC voltage source are used in conjunction with an ultrasonic liquid atomizing device, the electrical input must be increased higher than the steady current when the liquid atomizing device is started.
  • the hysteresis problem may be overcome by the following two methods.
  • the first method will be described with reference to FIG. 2.
  • a two-input DC voltage source is used as a DC power source for the ultrasonic oscillator, and a switching circuit for selecting one of the two outputs and a control circuit for controlling this switching circuit are provided.
  • a switching circuit comprises a relay with a movable contact 122 and stationary contacts 122A, 122B and 122C and a capacitor 29.
  • One DC output is derived directly whereas the other DC output is derived through a resistor 25. That is, when the normally opened contact 12213 is closed, the high voltage is applied to the oscillator whereas when the low voltage is normally supplied to the oscillator through the nor mally closed contact 122A connected to the resistor 25.
  • the control circuit for controlling the switching circuit comprises a coil 121 of the relay 120, a switching transistor 26, a capacitor 27 and a resistor 28.
  • the line voltage is applied to the input terminals 20 and 21, the current flows into the base of the transistor 26 through the capacitor 27 and 28 so that the transistor 26 is turned on.
  • the relay 120 is energized so that the normally opened contact 1223 is connected to the common contact 122C to apply the higher voltage to the ultrasonic oscillator. Since the output of the oscillator is dependent upon the voltage of the DC power source, the output is increased as the output voltage of the DC power source is increased.
  • the base current of the transistor 26 is exponentially decreased and so is the collector current.
  • the relay 120 is de-energized so that the normally closed contact 122A is closed again.
  • the lower voltage is therefore applied to the ultrasonic generator through the resistor 25, so that the output of the ultrasonic generator is also decreased. It is very simple to set the voltage across the capacitor 24 to such a level that liquid may be sufficiently atomized and to select the value of the resistor 25 in such a manner that the steady output may be supplied to the ultrasonic generator.
  • the capacitor 73 is short-circuited so that the base current of the transistor 71 is high so that the transistor 71 is turned on.
  • the control input voltage of the voltage regulator drops.
  • the values of the variable resistor 67 and resistor 68 are so selected that the decrease in control input voltage is less than the breakdown voltage of the zener diode 32. Therefore, the output voltage becomes zero in practice.
  • the collector current of the transistor 71 is reduced to zero so that the control input voltage is increased to a 100 percent level.
  • a solenoid valve 92 is inserted between sections of pipe 90 and 91 for feeding liquid to the liquid atomizing horn 12, and is controlled by a control circuit 100 in response to the variation in frequency or amplitude of the ultrasonic transducer 10, that is the driving current flowing through the coil 11 thereof.
  • the solenoid valve 92 when the amplitude of oscillation is in excess of a predetermined level, the solenoid valve 92 is opened so that the liquid is supplied, but when the amplitude becomes lower than a predetermined level the solenoid valve 92 is closed to interrupt the supply of the liquid fuel to the atomizing horn 12.
  • the control circuit 100 comprises a relay and a Schmitt circuit interconnected in such a manner so that when the amplitude becomes lower than a predetermined level, the relay is energized so that the supply of current from the feed line through terminals 101 and 102 to the solenoid valve 92 is cut off.
  • the DC voltage across the capacitor 24 may be supplied to the Schmitt circuit (not shown) through a pair of input terminals 103 and 105 whereas the input voltage or signal is applied to the terminal 104 of the Schmitt circuit from the capacitor 66.
  • the driving current flowing through the coil 11 is decreased so that the voltage across the capacitor 66 is also decreased.
  • the Schmitt circuit is triggered to energize the relay so as to interrupt the current supply to the solenoid valve 92, thereby interrupting the fuel supply to the horn 12.
  • a thermistor is positioned within the liquid supply line so as to detect the temperature of the liquid.
  • the thermistor 80 is connected to the variable resistor 67 so that the contol input voltage applied to the DC voltage regulator is dependent upon the variation in resistance of the thermistor 80 in response to the temperature variation.
  • the output voltage of the DC voltage regulator is varied in response to the temperature change so that the amplitude of oscillation of the oscillating surface 13 of the horn 12 may be varied in response to the temperature variation. That is, when the temperature of liquid supplied drops, the control input voltage to be applied to the DC voltage regulator also drops so that the output voltage of the DC voltage regulator rises. As a result, the output voltage of the ultrasonic generator rises so that the amplitude of oscillation at the oscillating surface 13 of the horn 12 is increased. Thus, the liquid may be atomized to a predetermined degree.
  • reference numeral 1 denotes a section generally indicated by 1 in FIG. 1 including the oscillator and the DC power source for supplying DC to the ultrasonic generator.
  • An ignition transformer 2 is provided in order to produce a spark between the oscillating surface 203 and an ignition plug 202 supported by an insulator.
  • Combustion air is supplied into a housing 301 by a blower 3 driven by a motor.
  • a photocell or photoelectric transducer means 401 is disposed within the housing 301 in such a manner that it may intercept the light from the flame through an opening 403 when combustion air is flowing through the housing 301, but it may not intercept the light by a shield member 402 when combustion air is not supplied into the housing 301.
  • the ultrasonic liquid atomizer comprising the ultrasonic transducer, the fuel supply pipe, the ignition plug and the blower and the photoelectric transducer means 401. Air flows within the housing 301 around the ultrasonic transducer 10 and the atomizing horn 12 and is discharged through openings 302 and 403 into a combustion chamber.
  • a protective relay 6 contols, in response to the signal from the photoelectric transducer means 401, the ignition transformer 2, the control circuit of the solenoid valve 92 and a post purge timer 5 to be described hereinafter. Power is supplied through a pair of terminals 601 and 602 and a switch 503 to the relay 6.
  • the post purge timer 5 is adapted to control the ultrasonic generator and the DC power source 1 and the motor for driving the blower 3.
  • the switch 603 When the switch 603 is closed, power is supplied to the ignition transformer 2, the post purge timer 5 and the control circuit 100 through the protective relay 6 and also to the driving device 1 including the ultrasonic oscillator and the DC power source and the blower motor.
  • the driving current flows through the coil 11 of the ultrasonic transducer 10 to cause the oscillations, and the combustion air is supplied by the blower 3 through the housing 301 into the combustion chamber.
  • the solenoid valve 92 is energized to open itself to supply the liquid fuel to the nozzle 14 of the horn 12 through the pipe lines 91 and 90.
  • Liquid fuel is atomized at the end or oscillating surface 13 of the horn l2 and mixed with primary air supplied by the blower 3, and the fuel-air mixture is ignited by the spark generated between the ignition plug 202 and the edge 203 of the end surface 13 of the horn.
  • a timer incorporated within the protective relay 6 interrupts the power supply to the ignition transformer 2, and the steady state combustion is started.
  • the shield member 402 is in the position indicated by the dotted lines in FIG. 3 because primary air is supplied so that the photoelectric transducer means 401 intercepts the light from the flame through the opening 403 and gives the signal to the protect relay 6.
  • the switch 603 is opened so that the power supply to the solenoid valve 92 is interrupted.
  • liquid fuel supply to the horn 12 is also interrupted.
  • the power supply from the protect relay 6 to the post purge timer 5 through a pair of terminals E and F is interrupted, but the power is supplied to the post purge timer 5 from the terminal 602 so that the power supply to the blower motor and to the driving device 1 is maintained for a predetermined time through the terminals 20 and 21. That is, the post purge timer 5 functions as an off-delay timer. Since the power is supplied to the blower moter and to the driving device 1 in the manner described above, the liquid fuel remaining in the pipe line 90 is burnt or atomized and discharged into the combustion chamber so that no liquid fuel remains within the housing 301.
  • the shield member 402 moves to the position indicated by the solid lines in FIG. 3 so that no light is intercepted by the photoelectric transducer means 401.
  • the protective relay 6 interrupts the power supply to the solenoid valve 92 and to the post purge timer 5, so that the combustion is stopped.
  • the shield member 402 functions as means for detecting whether primary air is supplied or not.
  • the protective relay 6 interrupts the power supply from the protective relay 6 to the solenoid valve 92 so that the solenoid valve 92 is closed.
  • the photoelectric transducer means 401 does not detect the light from combustion flames and the protective relay 6 functions to interrupt the power supply to the solenoid valve 92 and to the post purge timer 5.
  • the post purge timer 5 which functions as off-delay timer means will be described in more detail hereinafter.
  • Commercial voltage applied to a terminal F is rectified and smoothed by a series-connected circuit comprising a diode 501 and a capacitor 502, and the voltage across the capacitor 502 is applied through a resistor 503 to the base of a switching transistor 504 whose load is a coil 505 of a relay, A normally closed contact 505A of the relay is connected to the terminal F; a normally open contact 5058 is connected to a terminal 602; and a common contact 505C is connected to the terminal 21.
  • the voltage applied to the terminal 21 is rectified and smoothed by a series-connected circuit comprising a diode 506, a resistor 507 and a capacitor 509, and the voltage across the capacitor 509 is applied to the relay coil 505, the transistor 504 and a resistor 508.
  • the switch 603 (See FIG. 3) is closed, the commercial power is supplied so that the base current flows into the transistor 504.
  • the transistor 504 is turned on to energize the relay so that the movable contact 505D interconnets the normally opened contact 505B and the common contact 505C.
  • the power supply through the terminal F is interrupted, and the capacitor 502 is dischared through the base of the transistor 504 and the resistor 503.
  • the discharging current is decreased in time expotentially so that the collector current of the transistor 504 which flows through the relay coil 505 is also reduced.
  • the relay is de-energized so that the movable contact 505D interconnects the normally closed contact 505A and the common contact 505C.
  • no power is applied to the terminal F so that no power is supplied from the terminal 21.
  • the power supply through the terminal 21 is interrupted a predetermined time interval after the interruption of power supply from the protective relay 6 through the terminal F.
  • the ultrasonic transducer whose Q is high and damped admittance is sufficiently small as compared with the motional admittance at a resonant frequency is driven always at its resonant frequency in a very efficient manner. Since only the positive feedback circuit is provided, in such a manner that the driving current flowing through the coil is converted into the voltage which in turn is fed back to the amplifier circuit, the circuit is very simple in construction. Furthermore, the voltage regulator maintains a predetermined constant voltage so that the oscillation of the ultrasonic transducer may be maintained constant by the negative feedback of the driving current. The voltage regulator also serves to compensate the fluctuation of the commercial or line voltage so that the constant oscillation of the ultrasonic transducer may be further ensured. Moreover, the very effective andautomatic liquid atomization can be effected when a simple additional circuit is added, and a very safe ultrasonic liquid fuel burner may be provided when a simple mechanism and circuit are added.
  • the transducer has been described as being a magnetostrictive device, but it will be understood that the present invention is also applied to a piezoelectric device because, according to the presnet invention, it is not required to provide a coil for detecting oscillation in addition to the driving coil.
  • An ultrasonic generator comprising in combination a. an ultrasonic transducer whose motional admittance becomes maximum at a resonant frequency
  • an oscillator comprising an amplifier driving said ultrasonic transducer with a square waveform voltage at a frequency substantially equal to said resonant frequency, whereby a surface of the transducer oscillates and a feedback circuit for feeding back to said amplifier an AC control voltage in proportion to the driving current which drives said ultrasonic transducer,
  • a DC power source for supplying DC power to said oscillatonsaid DC power source being provided with a DCvoltage regulator and (1. means for converting said AC control voltage into a DC control input voltage for said regulator.
  • An ultrasonic atomizer comprising an ultrasonic generator as defined in claim 1 further comprising means for supplying liquid to be atomized to the oscillating surface of said ultrasonic transducer.
  • An ultrasonic atomizer comprising an ultrasonic generator as defined in claim 1 wherein said DC power source comprising means for selectively supplying two different output voltages.
  • An ultrasonic atomizer as defined in claim 4 further comprising means responsive to said driving current for controlling the flow rate of liquid to be supplied to said ultrasonic transducer.
  • An ultrasonic atomizer as defined in claim 4 further comprising means responsive to said driving current for controlling the flow rate of liquid to be supplied to said ultrasonic transducer.
  • An ultrasonic atomizer as defined in claim 2 further comprising timer means connected to said DC voltage regulator for increasing said control input voltage from percent to 100 percent within a predetermined time interval.
  • An ultrasonic generator as defined in claim 7 further comprising means responsive to said driving current for controlling the flow rate of liquid to be supplied to said ultrasonic transducer.
  • An ultrasonic atomizer as defined in claim 7 further comprising means for detecting the temperature of liquid to be atomized and for varying said control input voltage in response to the detected temperature.
  • An ultrasonic atomizer comprising in combination a. an ultrasonic transducer whose motional admittance becomes maximum at a resonant frequency
  • an oscillator comprising an amplifier driving said ultrasonic transducer with a square waveform voltage at a frequency substantially equal to said resonant frequency, wherebythe surface of the transducer oscillates and a feedback circuit for feeding back to said amplifier an AC control voltage in proportion to the driving current which drives said ultrasonic transducer,
  • liquid to be atomized to the oscillating surface of said ultrasonic transducer and e. means responsive to said driving current for con-.
  • An ultrasonic liquid fuel burner comprising A an ultrasonic generator comprising a. an ultrasonic transducer whose motional admittance is maximum at a resonant frequency,
  • an oscillator comprising an amplifier adapted to drive said ultrasonic transducer with a square waveform voltage at a frequency substantially equal to said resonant frequency, and a feedback circuit for feeding back to said amplifier an AC voltage in proportion to the driving current which drives said ultrasonic transducer,
  • a DC power source for supplying DC power to said oscillator
  • G means for controlling the supply of liquid fuel to be supplied to said ultrasonic transducer
  • An ultrasonic liquid fuel burner as defined in claim 11 further comrising means for detecting whether air is flowing through said housing means, said power supply control means being adapted to be actuated in response to the signals from said air flow detecting means.
  • An ultrasonic liquid fuel burner as defined in claim 11 further comprising means responsive to said driving current for controlling said liquid fuel supply control means.
  • An ultrasonic liquid fuel burner as defined in claim 11 further comprising timer means for delaying the operation of said DC power source and said motor of said blower.
  • An ultrasonic liquid fuel burner comprising A. an ultrasonic generator comprising a. an ultrasonic transducer whose motional admittance is maximum at a resonant frequency,
  • an oscillator comprising an amplifier means for driving said ultrasonic transducer with a square waveform voltage at a frequency substantially equal to said resonant frequency whereby a surface of said transducer oscillates, and a feedback circuit for feeding back to said amplifier an AC voltage in proportion to the driving current which drives said ultrasonic transducer,
  • a DC power source for supplying DC power to said oscillator
  • converter means for providing a DC voltage in proportion to said driving current, a control circuit connected to said converter means for controlling DC power source, and
  • G means for interrupting the operation of said DC power source, said ignition electrode, said motordriven blower and said liquid fuel supply control means in response to an absence of said combustion signal.
  • An ultrasonic liquid fuel burner as defined in claim 15 further comprising means for' detecting whether combustion air is flowing through said housing means, said interrupting means being adapted to be actuated in response to the signals from said air flow detecting means.
  • An ultrasonic liquid fuel burner as defined in claim 15 further comprising means for controlling said liquid fuel supply control means in response to said driving current.
  • An ultrasonic liquid fuel burner as defined in claim 15 further comprising timer means responsive to the interruption of power to said liquid fuel supply control means for initially delaying the interruption of power from said two-output DC power source to said motor-driven blower.
  • An ultrasonic liquid fuel burner as defined in claim 15 further comprising means for varying said DC voltage from said converter means in response to the temperature of liquid fuel to be atomized.
  • An ultrasonic liquid fuel burner as defined in claim 19 further comprising means for detecting whether combustion air is flowing through said housing means, and means for actuating said interrupting means in response to the signals from said air flow detecting means.
  • An ultrasonic liquid fuel burner as defined in claim 19 further comprising means for controlling said liquid fuel supply control means in response to said driving current.
  • An ultrasonic liquid fuel burner as defined in claim 19 further comprising timer means responsive to the interruption of power to said liquid fuel supply control means for initially delaying the interruption of power from said two-output DC power source to said motor-driven blower.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Special Spraying Apparatus (AREA)
  • Apparatuses For Generation Of Mechanical Vibrations (AREA)
  • Pressure-Spray And Ultrasonic-Wave- Spray Burners (AREA)
  • Oscillators With Electromechanical Resonators (AREA)
US381786A 1972-07-31 1973-07-23 Ultrasonic generator and burner Expired - Lifetime US3885902A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47077218A JPS5123342B2 (zh) 1972-07-31 1972-07-31

Publications (1)

Publication Number Publication Date
US3885902A true US3885902A (en) 1975-05-27

Family

ID=13627694

Family Applications (1)

Application Number Title Priority Date Filing Date
US381786A Expired - Lifetime US3885902A (en) 1972-07-31 1973-07-23 Ultrasonic generator and burner

Country Status (14)

Country Link
US (1) US3885902A (zh)
JP (1) JPS5123342B2 (zh)
AT (1) AT346614B (zh)
BE (1) BE803001A (zh)
CA (1) CA984282A (zh)
CH (1) CH588303A5 (zh)
DE (1) DE2338503C3 (zh)
FR (1) FR2195172A5 (zh)
GB (1) GB1441951A (zh)
IT (1) IT992746B (zh)
NL (1) NL179555C (zh)
NO (1) NO140456C (zh)
SE (1) SE396702B (zh)
ZA (1) ZA735101B (zh)

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4044297A (en) * 1975-05-20 1977-08-23 Matsushita Electric Industrial Co., Ltd. Ultrasonic generator with combined oscillator and current regulator
US4081233A (en) * 1975-06-19 1978-03-28 Matsushita Electric Industrial Co., Ltd. Combustion device
EP0042903A1 (en) * 1980-06-30 1982-01-06 Mario Francesco Vota Apparatus for homogenizing a fluid flowing through a duct by means of ultrasonic waves
US4316580A (en) * 1979-07-13 1982-02-23 Sontek Industries, Inc. Apparatus for fragmenting fluid fuel to enhance exothermic reactions
US4347983A (en) * 1979-01-19 1982-09-07 Sontek Industries, Inc. Hyperbolic frequency modulation related to aero/hydrodynamic flow systems
US4488816A (en) * 1982-12-27 1984-12-18 Vota Mario F Apparatus for the generation and the automatic control of ultrasonic waves in the treatment of fluids
EP0421439A2 (de) * 1989-10-05 1991-04-10 Firma J. Eberspächer Ultraschallzerstäuber
US5216338A (en) * 1989-10-05 1993-06-01 Firma J. Eberspacher Circuit arrangement for accurately and effectively driving an ultrasonic transducer
WO1994014003A1 (en) * 1992-12-15 1994-06-23 Bha Group, Inc. Acoustically enhanced combustion method and apparatus
US5394047A (en) * 1993-02-12 1995-02-28 Ciba Corning Diagnostics Corp. Ultrasonic transducer control system
US5785012A (en) * 1992-12-15 1998-07-28 Bha Group Holdings, Inc. Acoustically enhanced combustion method and apparatus
EP0919291A2 (en) * 1997-11-29 1999-06-02 KOREA INSTITUTE OF MACHINERY & METALS Circuit for driving magnetostrictive device
WO2001076762A3 (en) * 2000-04-12 2002-04-04 Instrumentarium Corp Method of maximizing the mechanical displacement of a piezoelectric nebulizer apparatus
US20050061848A1 (en) * 2003-09-22 2005-03-24 Johansen David K. Multiple probe power systems and methods for ultrasonic welding
US20060179946A1 (en) * 2005-02-01 2006-08-17 Beckman Coulter, Inc. Method and apparatus for washing a probe or the like using ultrasonic energy
US20060266350A1 (en) * 2005-05-25 2006-11-30 Luca Bidolli Device for burning gasified liquid fuels
ITMI20090654A1 (it) * 2009-04-20 2009-07-20 Zobele Holding Spa Atomizzatore di liquidi con dispositivo di vibrazione piezoelettrico a circuito elettronico di controllo perfezionato e relativo metodo di azionamento.
US20090317756A1 (en) * 2008-06-18 2009-12-24 Mestek, Inc. Digital high turndown burner
US10461697B2 (en) 2014-08-29 2019-10-29 Murata Manufacturing Co., Ltd. Oscillation circuit and oscillation-circuit driving method
US10710310B1 (en) 2019-08-15 2020-07-14 Dukane Ias, Llc Multipoint controllers for power delivery to multiple probes in ultrasonic welding systems
CN112583395A (zh) * 2020-12-03 2021-03-30 成都动芯微电子有限公司 超声波雾化片频率追踪系统及方法
EP3954415A4 (en) * 2019-04-09 2023-01-04 Japan Tobacco Inc. AEROSOL DELIVERY DEVICE
EP3954414A4 (en) * 2019-04-09 2023-03-22 Japan Tobacco Inc. AEROSOL SUPPLY DEVICE

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2391001A1 (fr) * 1977-05-18 1978-12-15 Satelec Soc Generateur d'ultra-sons
JPS613503Y2 (zh) * 1978-08-03 1986-02-03
JPS5848225B2 (ja) * 1979-01-09 1983-10-27 オムロン株式会社 超音波液体霧化装置の霧化量制御方式
JPS588818B2 (ja) * 1979-09-21 1983-02-17 株式会社 ロツテ 発泡性チユ−インガムの製造方法
DE3169595D1 (en) * 1980-11-10 1985-05-02 Gersonde Klaus Method of preparing lipid vesicles by ultrasonic treatment, the use of this method and apparatus for its application
US4452747A (en) * 1982-03-22 1984-06-05 Klaus Gersonde Method of and arrangement for producing lipid vesicles
DE3314609A1 (de) * 1983-04-22 1984-10-25 Siemens AG, 1000 Berlin und 8000 München Verfahren zum betrieb eines ultraschall-schwingers zur fluessigkeitszerstaeubung
DE3331896A1 (de) * 1983-09-03 1985-03-21 Gerhard Prof. Dr.-Ing. 8012 Ottobrunn Flachenecker Leistungsgenerator fuer einen ultraschallwandler
JPH065060B2 (ja) * 1985-12-25 1994-01-19 株式会社日立製作所 内燃機関用超音波式燃料微粒化装置の駆動回路
CS550488A3 (en) * 1987-08-17 1992-11-18 Satronic Ag Ultrasonic generator circuitry
DE19849217B4 (de) * 1997-11-12 2010-09-09 Centrotherm Elektrische Anlagen Gmbh & Co.Kg Anordnung zur Reinigung von Gasaustrittsöffnungen und/oder deren Zuleitungen

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3121534A (en) * 1960-09-29 1964-02-18 Exxon Research Engineering Co Supersonic liquid atomizer and electronic oscillator therefor
US3155141A (en) * 1962-06-18 1964-11-03 Little Inc A Apparatus for atomizing and burning a liquid fuel
US3177416A (en) * 1960-10-04 1965-04-06 Philips Corp Driving oscillator for producing supersonic oscillations
US3214101A (en) * 1964-03-31 1965-10-26 Little Inc A Apparatus for atomizing a liquid
US3233650A (en) * 1959-02-27 1966-02-08 Cleall Alfred Frank Apparatus adapted to distinguish between the presence of flame due to combustion of fuel discharged from a burner and the absence of the flame
US3255804A (en) * 1963-08-15 1966-06-14 Exxon Research Engineering Co Ultrasonic vaporizing oil burner
US3275059A (en) * 1965-05-10 1966-09-27 Little Inc A Nozzle system and fuel oil burner incorporating it
US3434074A (en) * 1967-01-16 1969-03-18 Ohio State Univ Board Of Trust High speed,wide frequency range feedback circuit
US3544866A (en) * 1969-10-16 1970-12-01 C & B Corp Electronic drive circuitry for ultrasonic devices

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2949900A (en) * 1958-06-02 1960-08-23 Albert G Bodine Sonic liquid sprayer
DE1207487B (de) * 1960-10-04 1965-12-23 Philips Nv Hochfrequenzroehrengenerator mit piezomagnetischem Schwinger
DE1597012A1 (de) * 1966-02-18 1970-08-13 Sergio Uberti UEberschall-Erzeuger,insbesondere geeignet fuer Flaschenabfuellung am laufenden Band fuer gashaltige (Brause-) Getraenke
SE339346B (zh) * 1969-03-12 1971-10-04 Amlab Ab

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3233650A (en) * 1959-02-27 1966-02-08 Cleall Alfred Frank Apparatus adapted to distinguish between the presence of flame due to combustion of fuel discharged from a burner and the absence of the flame
US3121534A (en) * 1960-09-29 1964-02-18 Exxon Research Engineering Co Supersonic liquid atomizer and electronic oscillator therefor
US3177416A (en) * 1960-10-04 1965-04-06 Philips Corp Driving oscillator for producing supersonic oscillations
US3155141A (en) * 1962-06-18 1964-11-03 Little Inc A Apparatus for atomizing and burning a liquid fuel
US3255804A (en) * 1963-08-15 1966-06-14 Exxon Research Engineering Co Ultrasonic vaporizing oil burner
US3214101A (en) * 1964-03-31 1965-10-26 Little Inc A Apparatus for atomizing a liquid
US3275059A (en) * 1965-05-10 1966-09-27 Little Inc A Nozzle system and fuel oil burner incorporating it
US3434074A (en) * 1967-01-16 1969-03-18 Ohio State Univ Board Of Trust High speed,wide frequency range feedback circuit
US3544866A (en) * 1969-10-16 1970-12-01 C & B Corp Electronic drive circuitry for ultrasonic devices

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4044297A (en) * 1975-05-20 1977-08-23 Matsushita Electric Industrial Co., Ltd. Ultrasonic generator with combined oscillator and current regulator
US4081233A (en) * 1975-06-19 1978-03-28 Matsushita Electric Industrial Co., Ltd. Combustion device
US4347983A (en) * 1979-01-19 1982-09-07 Sontek Industries, Inc. Hyperbolic frequency modulation related to aero/hydrodynamic flow systems
US4316580A (en) * 1979-07-13 1982-02-23 Sontek Industries, Inc. Apparatus for fragmenting fluid fuel to enhance exothermic reactions
EP0042903A1 (en) * 1980-06-30 1982-01-06 Mario Francesco Vota Apparatus for homogenizing a fluid flowing through a duct by means of ultrasonic waves
US4488816A (en) * 1982-12-27 1984-12-18 Vota Mario F Apparatus for the generation and the automatic control of ultrasonic waves in the treatment of fluids
EP0421439A2 (de) * 1989-10-05 1991-04-10 Firma J. Eberspächer Ultraschallzerstäuber
EP0421439A3 (en) * 1989-10-05 1992-03-18 Firma J. Eberspaecher Ultrasonic atomiser
US5216338A (en) * 1989-10-05 1993-06-01 Firma J. Eberspacher Circuit arrangement for accurately and effectively driving an ultrasonic transducer
WO1994014003A1 (en) * 1992-12-15 1994-06-23 Bha Group, Inc. Acoustically enhanced combustion method and apparatus
US5785012A (en) * 1992-12-15 1998-07-28 Bha Group Holdings, Inc. Acoustically enhanced combustion method and apparatus
US5394047A (en) * 1993-02-12 1995-02-28 Ciba Corning Diagnostics Corp. Ultrasonic transducer control system
EP0919291A2 (en) * 1997-11-29 1999-06-02 KOREA INSTITUTE OF MACHINERY & METALS Circuit for driving magnetostrictive device
EP0919291A3 (en) * 1997-11-29 2001-05-16 KOREA INSTITUTE OF MACHINERY & METALS Circuit for driving magnetostrictive device
WO2001076762A3 (en) * 2000-04-12 2002-04-04 Instrumentarium Corp Method of maximizing the mechanical displacement of a piezoelectric nebulizer apparatus
US6539937B1 (en) 2000-04-12 2003-04-01 Instrumentarium Corp. Method of maximizing the mechanical displacement of a piezoelectric nebulizer apparatus
US20050061848A1 (en) * 2003-09-22 2005-03-24 Johansen David K. Multiple probe power systems and methods for ultrasonic welding
US7225965B2 (en) * 2003-09-22 2007-06-05 Dukane Corporation Multiple probe power systems and methods for ultrasonic welding
US20060179946A1 (en) * 2005-02-01 2006-08-17 Beckman Coulter, Inc. Method and apparatus for washing a probe or the like using ultrasonic energy
US20060266350A1 (en) * 2005-05-25 2006-11-30 Luca Bidolli Device for burning gasified liquid fuels
US20090317756A1 (en) * 2008-06-18 2009-12-24 Mestek, Inc. Digital high turndown burner
EP2244314A1 (en) * 2009-04-20 2010-10-27 Zobele Holding SpA Liquid atomiser with piezoelectric vibration device having an improved electronic control circuit, and activation method thereof
US20100264234A1 (en) * 2009-04-20 2010-10-21 Zobele Holding S.P.A. Liquid atomiser with piezoelectric vibration device having an improved electronic control circuit, and activation method thereof
ITMI20090654A1 (it) * 2009-04-20 2009-07-20 Zobele Holding Spa Atomizzatore di liquidi con dispositivo di vibrazione piezoelettrico a circuito elettronico di controllo perfezionato e relativo metodo di azionamento.
US8740107B2 (en) 2009-04-20 2014-06-03 Zobele Holding S.P.A. Liquid atomiser with piezoelectric vibration device having an improved electronic control circuit, and activation method thereof
US10461697B2 (en) 2014-08-29 2019-10-29 Murata Manufacturing Co., Ltd. Oscillation circuit and oscillation-circuit driving method
EP3954415A4 (en) * 2019-04-09 2023-01-04 Japan Tobacco Inc. AEROSOL DELIVERY DEVICE
EP3954414A4 (en) * 2019-04-09 2023-03-22 Japan Tobacco Inc. AEROSOL SUPPLY DEVICE
US10710310B1 (en) 2019-08-15 2020-07-14 Dukane Ias, Llc Multipoint controllers for power delivery to multiple probes in ultrasonic welding systems
CN112583395A (zh) * 2020-12-03 2021-03-30 成都动芯微电子有限公司 超声波雾化片频率追踪系统及方法
CN112583395B (zh) * 2020-12-03 2023-03-28 成都动芯微电子有限公司 超声波雾化片频率追踪系统及方法

Also Published As

Publication number Publication date
BE803001A (fr) 1973-11-16
SE396702B (sv) 1977-10-03
GB1441951A (en) 1976-07-07
JPS4934826A (zh) 1974-03-30
AT346614B (de) 1978-11-27
DE2338503C3 (de) 1981-09-03
NL179555B (nl) 1986-05-01
JPS5123342B2 (zh) 1976-07-16
ZA735101B (en) 1974-10-30
ATA667473A (de) 1978-03-15
CH588303A5 (zh) 1977-05-31
CA984282A (en) 1976-02-24
DE2338503B2 (de) 1980-11-20
FR2195172A5 (zh) 1974-03-01
NL179555C (nl) 1986-10-01
NO140456B (no) 1979-05-28
IT992746B (it) 1975-09-30
NO140456C (no) 1979-09-05
NL7310543A (zh) 1974-02-04
DE2338503A1 (de) 1974-02-21
AU5839273A (en) 1975-01-23

Similar Documents

Publication Publication Date Title
US3885902A (en) Ultrasonic generator and burner
US4044297A (en) Ultrasonic generator with combined oscillator and current regulator
US4435150A (en) Gas burner control system
US3975136A (en) Burner control system
US3255804A (en) Ultrasonic vaporizing oil burner
US4256987A (en) Constant current electrical circuit for driving piezoelectric transducer
US4019854A (en) Direct spark ignition system utilizing gated oscillator
US3575153A (en) Regulated voltage converter
US4299557A (en) Fuel burner control circuit
US3372306A (en) Proximity controlled automatic cigarette lighter and the like
US3439991A (en) Dryer control
US4443157A (en) Control circuit for a liquid fuel combustion apparatus
JPS5913264B2 (ja) 超音波液体霧化装置
US3412293A (en) Burner control apparatus with photodarlington flame detector
US3983472A (en) Chokeless Schmitt-trigger regulator
US3034023A (en) Low cost controller
CN219199259U (zh) 一种数字式脉冲点火电路及燃具
US4689006A (en) Spark ignition system with positive suppression of spark when pilot flame is sensed
JPS593241Y2 (ja) 燃焼安全装置
US3643706A (en) Proximity control apparatus
JPS5913263B2 (ja) 超音波液体霧化装置
JPS6324356Y2 (zh)
JPS55102826A (en) Combustion device
JPS58203317A (ja) 燃焼機
KR820001718B1 (ko) 연료 주입장치