GB2196744A

GB2196744A - Indicating power developed by ultrasonic transducer

Info

Publication number: GB2196744A
Application number: GB08620765A
Authority: GB
Inventors: Roy Underwood
Original assignee: Kerry Ultrasonics Ltd
Current assignee: Kerry Ultrasonics Ltd
Priority date: 1986-08-28
Filing date: 1986-08-28
Publication date: 1988-05-05
Also published as: GB8620765D0

Abstract

Ultrasonic apparatus is disclosed which includes an ultrasonic transducer (2, 3), a generator of electrical energy for energising the transducer (1), means for generating an electrical signal dependent on the power supplied to the transducer (4, 5, 6, 7, 8) and indicator means (9) for providing a luminous indication of the power. The apparatus disclosed gives a luminous display which is easy for the operator to see and in general can be relatively inexpensive to provide and is applicable both to ultrasonic welding apparatus and ultrasonic cleaning apparatus. The indicator means may preferably comprise a light-emitting diode or bar-graph display. <IMAGE>

Description

SPECIFICATION Ultrasonic apparatus This invention concerns ultrasonic apparatus and more particularly the conversion of electrical energy into ultrasonic energy.

Ultrasonic apparatus is widely used for a number of purposes, for example for solvent cleaning, welding, non-destructive testing and medical diagnostics. In order to use such apparatus effectively, it is important that adequate ultrasonic energy is produced by the transducers in the apparatus in order to achieve the desired result, and this in turn requires an adequate consumption of electrical power by the transducers.

Ultrasonic apparatus requiring high levels of ultrasonic energy output usually have an analogue meter providing a numerical indication of the electrical power applied to its transducers, which in turn indicates the acoustic loading of the transducers and thence the ultrasonic energy being produced by the transducers. Various factors influence acoustic loading of the transducers in such apparatus and in general acoustic coupling is maximised by the operator when the apparatus is switched on. Frequently, however, operators of such apparatus having set the acoustic coupling fail to make adjustments as it drifts from optimum. The consequences are often not immediately apparent. For example, a weld produced under such conditions may appear satisfactory but in fact it may be insufficiently strong and fail when the welded object is used.

Some ultrasonic apparatus, for example certain ultrasonic cleaning equipment, has no indication of the power consumed by its transducers, the apparatus being set up during manufacture to optimise acoustic coupling.

Factors such as solvent level in the cleaning bath and temperature of the cleaning bath can both affect acoustic coupling. Inefficient coupling with such apparatus means that cleaning becomes poor and it can become totally ineffective. In such cases, the user may be unaware that the apparatus is not functioning correctly and may pass dirty articles, for example printed circuit boards for computers, for further processing. This can lead to expensive break-downs of other equipment.

The present invention seeks to overcome the disadvantages of such prior art ultrasonic apparatus by providing an indication of power transfer to transducers thereof which is particularly easily noticed by an operator of the apparatus, and by providing a visual display which does not add significantly to the cost of ultrasonic apparatus which does not usually have a meter to indicate power transfer.

According to the present invention there is provided ultrasonic apparatus comprising an ultrasonic transducer, a generator of electrical energy for energising the transducer, means for generating an electrical signal dependant on the power supplied to the transducer, and indicator means for providing a luminous indication of power supplied to the transducer.

Apparatus in accordance with the invention give a luminous display which is easy for the operator to see and in general can be relatively inexpensive to provide.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings in which: Figure 1 shows a block diagram of ultrasonic welding apparatus of the invention and Figure 2 shows a block diagram of ultrasonic cleaning apparatus of the invention.

Referring to Fig. 1, a high frequency electrical generator 1 is connected to a transducer 2 having a welding horn 3 attached. High frequency electrical current through the transducer is sensed by a current sensor 4 and the potential applied is sensed by a voltage sensor 5. Signals from the sensors 4 and 5 are combined in known manner in a signal processor 6 which provides an output proportional to the product of the sensed current and voltage, i.e. proportional to the power applied to the transducer since these signals each contain a component dependent on phase. The output from the processor 6 is then passed through a low pass filter 7 which provides a D.C. potential proportional to the average power to the transducer 2 on to a bargraph driver 8 which in turn drives a bargraph display 9.

The ultrasonic cleaning apparatus illustrated in Fig. 2 functions in a similar manner to the ultrasonic welding apparatus described with reference to Fig. 1, except the generator 1 is connected to transducers 21 and 21 attached to a cleaning bath 10.

In use, acoustic coupling is adjusted so that the bargraph display of the apparatus shown in Figs. 1 and 2 results in illumination of the maximum length or number of bars on the display 9. Alternatively, the bargraph display 9 can be replaced by a single light emitting diode which is illuminated when at least a minimum satisfactory power transfer occurs between the generator 1 and the transducer 2 or 21.

In the case of ultrasonic solvent cleaning apparatus, inefficient acoustic couling may result from a low solvent levels, in which case more cleaning solvent should be added to given an indication of greater power consumption by the transducers.

1. Ultrasonic apparatus comprising an ultrasonic transducer, a generator of electrical energy for energising the transducer, means for generating an electrical signal dependant on the power supplied to the transducer, and indicator means for providing a luminous indica

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Ultrasonic apparatus This invention concerns ultrasonic apparatus and more particularly the conversion of electrical energy into ultrasonic energy. Ultrasonic apparatus is widely used for a number of purposes, for example for solvent cleaning, welding, non-destructive testing and medical diagnostics. In order to use such apparatus effectively, it is important that adequate ultrasonic energy is produced by the transducers in the apparatus in order to achieve the desired result, and this in turn requires an adequate consumption of electrical power by the transducers. Ultrasonic apparatus requiring high levels of ultrasonic energy output usually have an analogue meter providing a numerical indication of the electrical power applied to its transducers, which in turn indicates the acoustic loading of the transducers and thence the ultrasonic energy being produced by the transducers. Various factors influence acoustic loading of the transducers in such apparatus and in general acoustic coupling is maximised by the operator when the apparatus is switched on. Frequently, however, operators of such apparatus having set the acoustic coupling fail to make adjustments as it drifts from optimum. The consequences are often not immediately apparent. For example, a weld produced under such conditions may appear satisfactory but in fact it may be insufficiently strong and fail when the welded object is used. Some ultrasonic apparatus, for example certain ultrasonic cleaning equipment, has no indication of the power consumed by its transducers, the apparatus being set up during manufacture to optimise acoustic coupling. Factors such as solvent level in the cleaning bath and temperature of the cleaning bath can both affect acoustic coupling. Inefficient coupling with such apparatus means that cleaning becomes poor and it can become totally ineffective. In such cases, the user may be unaware that the apparatus is not functioning correctly and may pass dirty articles, for example printed circuit boards for computers, for further processing. This can lead to expensive break-downs of other equipment. The present invention seeks to overcome the disadvantages of such prior art ultrasonic apparatus by providing an indication of power transfer to transducers thereof which is particularly easily noticed by an operator of the apparatus, and by providing a visual display which does not add significantly to the cost of ultrasonic apparatus which does not usually have a meter to indicate power transfer. According to the present invention there is provided ultrasonic apparatus comprising an ultrasonic transducer, a generator of electrical energy for energising the transducer, means for generating an electrical signal dependant on the power supplied to the transducer, and indicator means for providing a luminous indication of power supplied to the transducer. Apparatus in accordance with the invention give a luminous display which is easy for the operator to see and in general can be relatively inexpensive to provide. Embodiments of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings in which: Figure 1 shows a block diagram of ultrasonic welding apparatus of the invention and Figure 2 shows a block diagram of ultrasonic cleaning apparatus of the invention. Referring to Fig. 1, a high frequency electrical generator 1 is connected to a transducer 2 having a welding horn 3 attached. High frequency electrical current through the transducer is sensed by a current sensor 4 and the potential applied is sensed by a voltage sensor 5. Signals from the sensors 4 and 5 are combined in known manner in a signal processor 6 which provides an output proportional to the product of the sensed current and voltage, i.e. proportional to the power applied to the transducer since these signals each contain a component dependent on phase. The output from the processor 6 is then passed through a low pass filter 7 which provides a D.C. potential proportional to the average power to the transducer 2 on to a bargraph driver 8 which in turn drives a bargraph display 9. The ultrasonic cleaning apparatus illustrated in Fig. 2 functions in a similar manner to the ultrasonic welding apparatus described with reference to Fig. 1, except the generator 1 is connected to transducers 21 and 21 attached to a cleaning bath 10. In use, acoustic coupling is adjusted so that the bargraph display of the apparatus shown in Figs. 1 and 2 results in illumination of the maximum length or number of bars on the display 9. Alternatively, the bargraph display 9 can be replaced by a single light emitting diode which is illuminated when at least a minimum satisfactory power transfer occurs between the generator 1 and the transducer 2 or 21. In the case of ultrasonic solvent cleaning apparatus, inefficient acoustic couling may result from a low solvent levels, in which case more cleaning solvent should be added to given an indication of greater power consumption by the transducers. CLAIMS

1. Ultrasonic apparatus comprising an ultrasonic transducer, a generator of electrical energy for energising the transducer, means for generating an electrical signal dependant on the power supplied to the transducer, and indicator means for providing a luminous indica tion of power supplied to the transducer.

2. Apparatus according to claim 1, wherein the indicator means comprises a light emitting diode.

3. Apparatus according to claim 1 or claim 2, wherein the indicator means comprises a bargraph display.

4. Apparatus according to any of the preceding claims, in the form of ultrasonic welding apparatus.

5. Apparatus according to any of claims 1 to 3, in the form of ultrasonic cleaning apparatus.