Ultrasonic cleaner basics | Ultrasonic cleaner types
This page describes Ultrasonic cleaner basics including its parts and functions of each. It mentions types of ultrasonic cleaner and their use. It explains basic working principle of ultrasonic cleaner and its benefits.
Ultrasonic cleaner definition: The device which uses ultrasonic frequency waves to clean the objects is known as ultrasonic cleaner and the process is known as ultrasonic cleaning. Ultrasonic frequency ranges from 20 KHz to 200 KHz which is outside the audible range of human beings.
It is ultimate method which cleans objects from dust, dirt, grime and other contaminants from outer and inner surfaces. Moreover it does not damage the object physically. It is used in many applications which include Microelectronics, medical devices, hard-disk drives, biomedical, optics, automotive components, jewelry cleaning etc.
Typical applications are as follows.
• Used in metal industries to clean oil, grease and other contaminants. It is used to polish compounds before plating operation.
• Used to remove flux from PCB and to clean it from dust.
• Used to clean jewellary and ornaments.
• Used to clean dental tools by dentists.
• Used to clean glasses, watches, screws etc.
Ultrasonic cleaner components and working principle
It works based on ultrasonic energy in ultrasonic frequency band. With the help of proper ultrasonic devices, bubbles are created which passes through the liquid. Bubbles rapidly increases in size and implode against the surface of the object immersed in the tank. The resulting energy release lifts off contamination from the surface and innermost recesses. Energy needed to form cavitation bubbles in liquid is proportional to surface tension and vapour pressure.
The figure-1 depicts typical components used in the ultrasonic cleaner.
As shown it consists of ultrasonic generator, transducers, radiating diaphragm,
metal tank and cleaning agent or aqueous solution.
Let us understand functions of each of these modules or systems.
• Ultrasonic generator: It converts electrical energy from power source of 50/60 Hz frequency into electrical energy at higher ultrasonic frequencies. It energizes the transducers. Each transducer needs certain minimum voltage (about 75%) to activate. Each generator is available with power and frequency sweep control. The transducers operate from 18 KHz to 120 kHz with energy density of about 100 Watt/gallon of fluid.
• Transducers: The electrical energy at ultrasonic frequencies are applied to transducers which are mounted on bottom or sides or both places. There are two types of transducers viz. piezoelectric type and magneto-strictive type. Both of these types produce mechanical energy in the form of vibrations. These are being passed through the liquid through radiating plate or diaphragm. Let us understand difference between Piezoelectric transducer and Magnetostrictive transducer.
Magnetostrictive transducers utilize the principle of magnetostriction in which certain materials will expand and contract when they are placed in alternating H field (magnetic field).
Piezoelectric transducers convert alternating electrical energy directly to the mechanical energy through the use of piezoelectric effect. Here certain materials change dimension when electrical charge (Q) is applied to these materials.
Also refer Ultrasonic cleaner working>>.
Ultrasonic cleaner types
The figure-2 depicts two major ultrasonic cleaner types. It includes industry grade ultrasonic cleaner and portable/desktop ultrasonic cleaner.
Portable/desktop models are light in weight. These cleaners are available in various sizes which will have different operating frequencies in ultrasonic range.
Desktop versions operate from 20 KHz to 40 KHz and from 40 KHz to 70 KHz. The 20-40 KHz version is used in cleaning engine blocks, heavy metal parts, removal of greasy oils. The 40-70 KHz version is used in cleaning optics, machine parts, dental tools and other components etc.
The other powerful versions operate from 70 KHz to 200 KHz. They are very expensive. They are used for cleaning jewellary, watches and contact lenses.
The ultrasonic cleaners are available which provides control over timing and temperature. Some of the cleaners are also equipped with power and frequency control.
Benefits of ultrasonic cleaning
Following are the benefits of Ultrasonic cleaning:
• Fast cleaning which saves time.
• Environmental friendly.
• Safe working environment.
• Perfect removal of contaminants.
• Energy efficient
Refer Advantages and Disadvantages of Ultrasonic cleaner>>.
Basics and types of transducers or sensors
Occupancy Sensor vs Motion Sensor
LVDT and RVDT sensor
Position, displacement and level sensor
force sensor and strain sensor