Aplicatorul are forma paralelipipedica cu dimensiunile:
L = 0,600 [m]
l = 0,400 - 0,450 [m]
H = 0,700 [m]
frecventa de lucru a aplicatorului este f = 2,45 GHz
temperatura mediului ambiant Ta = 20 [sC]
temperatura de incalzire a materialelor Tm = 40 [sC]
curentul anodic Ia = 0,7 [A]
intensitatea maxima a curentului electric emis de catod este: Jc = 0,15 [A/cm2]
tranversalele electrice TE450, TE651, TE646, TE441
Principii generale asupra dispozitivelor cu microunde
Energia microundelor a fost folosita in procesele industriale de foarte multi ani Folosirea acestora in locul surselor convetionale de caldura sa produs datorita mai multor avantaje cum ar fi :
incalzirea rapida in profunzime
economisire de energie si timp si imbunatatirea calitatii
In primii ani de studii a incalzirii prin microunde aceste avantaje au fost greu de justificat in raport cu pretul scazut al incalzirii cu ajutorul derivatiilor petrolului.
Toate acestea impreuna cu reticenta multor industrii de a schimba sistemele convectionale existente dar adesea eficiente si depasite cu sisteme cu sisteme bazate pe microunde a dus la o crestere lenta dar foarte bine documentata a acestei tehnologii.
Cele mai mari avantaje ale energiei microundelor asupra tehnologiei convetionale au fost bine precizate de catre Parkin (1979).
o mai eficienta uscare vizavi de perioada de uscare reducind costurile de productie
sistemul este mult mai compact decit sistemul conventional
energia este transferata intr-un mod mult mai curat (fara poluare)
se realizeaza afanarea materialului
absortia energiei in mod selectiv de catre constituentii cu pierderi ;acestora aplicinduse la uniformizarea materialelor fibroase
energia se disipa repede in vulumul materialului
evita uscarea excesiva
un cost relativ scazut al intretinerii
Generatoare de microunde
Magnetronul este un oscilator de putere in microunde. El lucreaza in regim de purtatoare sau impuls. In radiatie continua poate debita puteri de microunde de ordinul 20KW cu randament de 80%,iar in regim de impuls puteri de megawati, intrucit putera de virf Pv si puterea medie Pm, corespunde raportului intre perioada de repetitie T si durata impulsului .Banda de frecvente de lucru este ingusta deoarece magnetronul utilizeaza cavitati rezonante ,incorporate intr-un anod metalic masiv de obicei din Cu. Intr anod si catod se aplica o tensiune continua de ordinul miilor de volti.
Datorita cavitatilor rezonante prevazute in anod, cimpul electromagnetic de microunde are la rezonanta intensitate mare , astfel incit in obtinerea puterii de microunde prin frinarea electronilor, contribuie atit interactiunea indelungata cimp electric electron, cit si intensitatea mare a cimpului electric. Interactiunea are loc in timp ce electronii se deplaseaza in jurul catodului, in spatiul anod-catod.
Determinarea dimensiunii "l" pentru ca aplicatorul sa functioneze la frecventa de 2,45GHz
Pentru aceasta se foloseste urmatoarea fo�r�m�u�l�a�:�
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