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Theoretical and experimental analysis of series resonant converter for technical cleaning system

100%

Fabijański P. , Łagoda R.

tom Vol. 45, nr 8-9

164-167

Sandwich type piezoelectric ceramic transducers are the most frequently applied source of ultrasounds in technical cleaning system. They have the ability to radiate in an ultrasonic medium, e.g. water. with maximum acoustic power when the vibration is activated by a current whose frequency equals the mechanical resonance frequency of the transducer. The resonant frequency of the real circuit varies during the operation of many parameters, among others, the most important are temperature, time and the column of cleaning factor. In this situation, to obtain the maximum value of the converter efficiency. Its important role of control system to assure the optimal mechanical resonant frequencies of converter.

Ultradźwiękowe przetworniki typu sandwich są powszechnie stosowane w urządzeniach do mycia technologicznego. Efektywne mycie np. w wodnym roztworze środka myjącego jest możliwe, gdy przetwornik jest zasilany chwilowym napięciem o przebiegu quasi-sinusoidalnym z częstotliwością równą częstotliwości rezonansu mechanicznego przetwornika. Częstotliwość rezonansu mechanicznego w rzeczywistym obwodzie zmienia się w funkcji wielu parametrów, między innymi: temperatury, czasu, parametrów procesu mycia. W tej sytuacji, aby uzyskać maksymalną wartość energii akustycznej promieniowanej przez przetwornik do medium czyszczącego, istotne jest zastosowanie takiego układu automatycznej regulacji, który umożliwi dostrojenie częstotliwości pracy falownika do częstotliwości rezonansu mechanicznego przetwornika.

Mechanical properties of ultrasonic washed organic and traditional cotton yarns

84%

Uzun M. , Patel I.

Journal of Achievements in Materials and Manufacturing Engineering

2010

tom Vol. 43, nr 2

608--612

Purpose: The demand of natural and eco-friendly products have undergone tremendous growth after the awareness and realization of global ecological concerns. In this study we have used a novel product (organic cotton) and a novel system (ultrasonic), both having critical importance to environmental pollution. Cotton is one of the oldest and most abundant natural, biodegradable and renewable fibres. Although numerous synthetic fibres have been produced, cotton is still the most important fibre because of its unique physical properties like durability, strength and absorbency, furthermore, only 10% of the raw weight is lost during processing. Organic farming does not have any negative impact due to its natural growing abilities, in which the seeds genetic are not modified and no chemicals such as disinfect or fertilizer are used. Ultrasonic washing has many advantages such as the extra cleanliness of textile materials, reducing process time, energy and chemicals which are used in the washing process. In addition ultrasonic agitation brings less fibre migrations than conventional washing. Design/methodology/approach: The experimental section reports on the characterization of the organic and conventional cotton that were washed by using an ultrasonic process. Both of the cotton types that used in this study were Turkish cottons and manufactured by ring spinning system. The yarn samples were applied with two different washing temperatures (30°C and 40°C) and three different washing times (10, 20 and 30 minutes). The following stage of ultrasonic and conventional washing physical properties (yarn count, twist, tensile strength, elongation etc) was investigated and comparisons were made. Findings: The investigation presented in this study indicates benefits of employing ultrasonic washing and organic cotton farming. Research limitations/implications: The properties of yarn washed with ultrasonic energy shows better properties than those of yarns washed with conventional washing technique. The results confirms that ultrasonic washing has some advantages such as less processing time, less chemical and water consumptions compared to conventional washing methods. Originality/value: Organic cotton has a potential to substitute traditional cotton providing crop harvesting cost is significantly reduced.