Abstract: An ultrasonic cleaning system that includes an electrical power supply, and a plurality of ultrasonic transducers coupled in parallel, wherein the plurality of ultrasonic transducers are coupled to the electrical power supply. The ultrasonic cleaning system also includes a transducer fault indicator coupled between the electrical power supply and the plurality of ultrasonic transducers, wherein the transducer fault indicator consists essentially of a current sensing portion configured to detect electrical current, and an alarm mechanism coupled to the current sensing portion. Additionally, the alarm mechanism is configured to provide a signal, indicating a failure of the ultrasonic transducer, based on the magnitude of electrical current detected by the current sensing portion.

Abstract: A liquid condition sensor configured to monitor the condition of a liquid in an ultrasonic cleaning system tank, the liquid condition sensor including a first circuit configured to detect a signal transmitted from an ultrasonic generator to one or more ultrasonic transducers located in the tank. The liquid condition sensor further includes a second circuit coupled to the first circuit, the second circuit configured to determine if the signal is indicative of one of a suboptimal liquid level, and an unacceptably high concentration of dissolved gases in the cleaning liquid, and a third circuit coupled to the second circuit, the third circuit configured to provide a warning if one of a suboptimal liquid level, and an unacceptably high concentration of dissolved gases in the cleaning liquid is indicated by the second circuit.

Abstract: A liquid condition sensor configured to monitor the condition of a liquid in an ultrasonic cleaning system tank, the liquid condition sensor including a first circuit configured to detect a signal transmitted from an ultrasonic generator to one or more ultrasonic transducers located in the tank. The liquid condition sensor further includes a second circuit coupled to the first circuit, the second circuit configured to determine if the signal is indicative of one of a suboptimal liquid level, and an unacceptably high concentration of dissolved gases in the cleaning liquid, and a third circuit coupled to the second circuit, the third circuit configured to provide a warning if one of a suboptimal liquid level, and an unacceptably high concentration of dissolved gases in the cleaning liquid is indicated by the second circuit.

Abstract: An ultrasonic cleaning system that includes an electrical power supply, and a plurality of ultrasonic transducers coupled in parallel, wherein the plurality of ultrasonic transducers are coupled to the electrical power supply. The ultrasonic cleaning system also includes a transducer fault indicator coupled between the electrical power supply and the plurality of ultrasonic transducers, wherein the transducer fault indicator consists essentially of a current sensing portion configured to detect electrical current, and an alarm mechanism coupled to the current sensing portion. Additionally, the alarm mechanism is configured to provide a signal, indicating a failure of the ultrasonic transducer, based on the magnitude of electrical current detected by the current sensing portion.

Abstract: A generator for driving an ultrasonic transducer for use in ultrasonic cleaning. The generator is capable of maintaining substantially constant real output to a load while the output frequency of the generator is square wave frequency modulated about a wide bandwidth. Thus, the generator is capable of maintaining substantially constant real output to the load even if the output frequency is modulated substantially away from the load's resonant frequency. The square wave modulation of the output frequency causes improved cavitation of semi-aqueous cleaning solutions used in the load, and thus improves the cleaning action of the ultrasonic transducer.

Abstract: A generator for driving an ultrasonic transducer for use in ultrasonic cleaning. The generator is based on a voltage controlled oscillator which drives an output circuit which includes the ultrasonic transducer. The output circuit has a resonant frequency, and a resonance follower produces a control voltage which tunes the voltage controlled oscillator to the resonant frequency. Operating in conjunction with the automatic tuning elements is a constant power control which allows the user to set a desired power level, and monitors the actual output power by means of an output wattmeter circuit, to cause the actual output power to match the level selected by the user. The constant output power circuit is effective even during resonance tracking of the system, or during frequency modulation of the ultrasonic output energy.

Abstract: A wedge-shaped vibration-transmitting plate is located between the bottom wall of a cleaning tank and an ultrasonic transducer which is operable to produce vibratory energy in a liquid bath in the tank. The wedge-shaped plate diversifies the phase of initially in-phase energy waves produced by the transducer and causes waves of different phase to propagate upwardly through the liquid. As a result of the phase diversification, the concentration of high and low power levels at various depths in the bath is reduced so that cleaning action over the span of the vertical dimension is more uniform. In addition, the overall action of wave reflection at the upper surface of the bath fluctuates through a smaller range when the depth of the bath changes. This enables the transducer to be energized with a more stable input power.

Abstract: An ultrasonic cleaning system utilizes a manufacturing technique wherein one or more piezoelectric elements are fused, secured by a gold sputtering technique, or attached by electrochemical deposition to an associated metal surface, whether it be a metal cleaning tank or an electrode, by a gas-tight joint or connection, eliminating the necessity of utilizing conventional techniques that require bonding of the element or elements to the associated metal surfaces by epoxy compounds or the like. The novel technique is practiced, in some forms of the invention, by molding the piezoelectric elements integrally with ceramic materials utilized for the liquid cleaning tank itself, and thereafter polarizing the area or areas that are to be made piezoelectric. In other forms, a metal cleaning tank may be used, but in every instance the fusing of the piezoelectric mixture to the tank walls and/or electrodes is accomplished during the firing of the ceramic material of which the piezoelectric element is formed.

Abstract: An improved oscillator circuit, adapted especially for use in generating multi-frequency wave patterns occurring within the ultrasonic range, incorporates a transistor base drive network in which an alternate discharge path is used for coupling capacitors already known in circuits of this type. Power losses occurring in the transistors are lessened by employing transistors having reverse base-emitter breakdown voltage ratings that are higher than those conventionally employed. Use of the substituted transistors becomes possible by substituting the mentioned alternate discharge path, to compensate for the lower average discharge current that is known to pass through the base-emitter circuits of the transistors by reason of their higher reverse base-emitter breakdown voltages. The improved circuit in this way reduces power loss and its consequent temperature rise in the transistors and in their base and emitter resistors to increase output power to the accompanying reduction of transistor losses.