CUVANTINAINTE"Incepe sa fie recunoscuta in lume, inventivitatea romanilor, dovedita de altfel dc inaintasii nostri si dc rezultatele obtinute de catre participants la diferitele saloane de inventii raondiale si internationalc unde au obtinut numeroase premii speciale si medalii. Acestca au inceput, e drept, deocamdata timid sa sc transforme in produse, tehnologii, aparate fabricate in productic de serie.Un exemplu remarcabil il constituie activitatea inovativa depusa de Gogu Constantinescu, care a fost unul dintrc cci mai cunoscuti inventatori din toate timpurilc, el fund romanul cu cele mai multe inventii brcvetate (peste 300 dupa ultimelc documentari) alaturandu-se unor genii ca Edison , Tesla, Bell, Marconi, Coand* etc.Tratatul dc fata poate fi considerat ca o lucrare de exceptie, prezcntand in prima sa parte, viafa si activitatca celui care a stat alaturi de cele mai luminate minti ale omenirii in secolul XX. Totodata impresioncaza cititorii prin bogatia de informatii referitoare la teoria sonicitatii, fundamentele matematice si aplicatiile accsteia in varii domenii. Exemplul eel mai cunoscut este tragerea sincronizata, printre palclc elicei unui avion militar, invenfie care a dus la castigarea suprematiei aeriene, dc catre Royal Air Forces, in primul razboi mondial si salvarca a numeroase vieti.In cele 18 capitole ale acestci monografii, autorul, cl insusi cunoscut inventator si prcscdinte al filialei Transilvania a Societatii Inventatori lor din Romania a prezentat cu compctcnta si intr-o forma clara, stiintifica, pentru prima data in Romania, principiile fizice elementare ale sonicitatii, diferitele cfecte asupra paramctrilor energetici (debite, presiuni sonice, etc.) insistand asupra unor solujii constructive specifice, cum sunt motoarele sonice, convertoarele de cuplu si alte aplicatii.Autorul dr.ing., profesor la Universitatca Tehnica din Cluj-Napoca si ccrcetator cu inclinatii inventive, conduce in prezent colcctivul de Actionari Hidraulicc si Pneumatice din cadrul Catedrci dc Masini Uneltc si Roboti

Industrial! a Facultarii de Constructii de Masini, unde a incercat si a reusit sa aprofundeze, sa continuic si sa dezvolte mostenirca teoretica si practica ncpretuita, lasata dc acest mare om dc stiinja si inventator Academician Doctor Honoris Causa, ing. Gogu Constantinescu. Acestea cercetari realizate in cadruJ doctoraturii au condus la enunfarea unor tcze dc mare importanta stiintifica in care au fost gasite numeroase alte aplicafii de care va putea beneficia intreaga noastra natiune si de ce nu intreaga lume de pe aceasta plancta. Autorul a reusit ca procesul de creajie tehnica folosit de Gogu Constantinescu sa constituie un model pentru studcnti, doctoranzi si pcntru toti cei cu vocatic si cu pasiune pentru stiinfa.Nu pot sa inchei, fara a sublinia importanta deosebita pe care o are prezentarca in aceasta valoroasa lucrare, a listei integralc a brevctelor celui mai marc inventator roman, publicata pentru prima oara. Trebuie subliniat fapml ca autorul, Prof.univ.dr.ing. loan I. POP impreuna cu mult stimatul Prof.univ.dr.h.c.mult.ing. Radu MUNTEANU, Rectorul Universitatii Tehnice din Cluj-Napoca, au fost initiatorii infiintarii si acordSrii periodice a ..Ordinului Gogu Constantinescu", in grad de Cavaler, Ofiter, Comandor si Mare Comandor, de catre Societatea Inventatorilor din Romania, filiala Transilvania, unor inventatori romSni si straini sau altor personalitati stiintifice care s-au remarcat prin activitati deosebite in inventica si stiinta contribuind la progresul omenirii.La final subliniez ca aceasta carte se adreseaza in egala masura, inventologilor, inventatorilor, cercetatonlor si specialistilor din diferite domenii. studentilor, elevilor sau tuturor celor care sunt intercsati si iubesc stiintele tehnice, pentru care viafa si activitatea acestui mare om de stiinta si inventator reprezinta un cxemplu si un ideal pe care trebuie sa-1 urmezc.Presedintele Societatii InventatorUor din Romania Prof.univ.dr.ing fiz. Constantin Marin ANTOHIIasi, 2006

CUPRINSFOREWORD7CAPITOLUL 1GOGU CONSTANTINESCU 13CAPITOLUL 2DESPRE GOGU CONSTANTINESCU 212.1. Prezentare gcnerala 21CAPITOLUL 3-INCEPUTURILE SONICITATII 353.1. Incepiiturile in Romania - Conceperea sonicitatii353.1.1. Familia.'353.1.2. Scoala si inceputurile in Romania353.1.3. Germenii sonicitatii 393.2. Anglia - nasterca sonicitatii40-> 1 i n i...3.2.1. Pnmele transmisn sonice403.2.2. Intalnirea cu Edison433.2.3. Relatia Gogu Constantinescu - Walter Haddon443.3.Sincronizarea tragerii453.3.1. Istoricul sincronizarii tragerii463.4. Aparitia sonicitatii ca stiinfa si principiile ei de baza543.5. Invenjiile in domeniul transmisiilor pentruvehiculcle de transport593.6. Alte aplicatii ale sonicitatii703.7. Idci geniale stopate de lipsa fondurilor, birocratic si soarta74CAPITOLUL 4PRINCIPIILE FIZICE ELEMENTARE ALE SONICITATII754.1. Gencralitaji814.2. Actionari hidraulice cu debite armonice89

4.3.Proprietati caracteristice transmisiilor hidraulicecu debite alternative 894.4.Parametrii armonici. Definitii 904.4.1. Debite armonice sau sonice 904.4.2. Frecvente si lungimi de unda 924.4.3. Presiuni alternative sau sonice 934.4.4. Deplasamentul sonic 944.4.5. Perditanfa 954.4.6. Jmpedante hidraulice (Rezistenfc complexe) 954.4.6.1. Caderea de presiune datorata frecSriide-a lungul unci rezistente hidraulice 964.4.6.1.1.Dctcrminarea pierderilor liniarein hidraulica continua 974.4.6.1.2.Dctcrminarea pierderilor liniarein hidraulica sonica 994.4.6.2.Caderea de presiune datorata inerfieifluidului in miscare 1054.4.6.3.Caderea de presiune cauzata de corapresibilitatcafluidului 1094.4.6.3.1.Determinarea volumului de fluid necesarpentru a prelua prin corapresibilitatcvolumul debitat de generator Ill4.4.6.3.2.CapacitSji si condensatoare 1154.4.7. Tmpedanta rezistenfelor hidrauliceconectate in serie si in paralel 1304.4.7.1. Legarea in serie 1304.4.7.2. Legarea in paralel 1324.5. Considcrafii asupra legii fricfiunii 136CAPITOLUL 5EFECTELE CAPACITATII, INERTIEI, FRICTIUNII1 PERDITANTEI ASUPRA DEBITELOR SONICE 1475.1. Relatii de interdependenta intre parametrii sonici 1475.1.1. Relatia intre debit, capacitate si presiunea sonomotrice ... 1475.1.2. Relajia dintre debit, inertie si presiunea sonomotrice 1495.1.3. Relatia dintre debit, perditanfa si presiunea sonomotrice .. 1505.1.4. Relatia dintre debit, fricfiune si presiunea sonomotrice ... 151 5.2. Efectul combinat al frictiunii, capacitatii,inertiei si perditantei jntr-o conducts 1515.2.1. Legarea in serie a rezistcntelor, inerfiilor,capacitatilor si perditantelor 1512

5.2.2. Legarea in paralel a rezistentelor, inertiilor,capacitatilor si perditantelor1545.3. Lucrul mecanic1575.4. Energia potentiate a unei capacitati1615.5. Energia cinetica a unei inertii162CAPITOLUL 6PUTEREA SISTEMELOR CU DEBITE ARMONICE1756.1. Puterea instantanee1756.2. Puterea medie (Puterea activa)1756.3. Puterea datorata frictiunii1786.4. Puterea datorata rezistentelor inductive1786.5. Puterea datorata rezistentelor capacitive1806.6. Puterea pentru defazaj * 181CAPITOLUL 7DEBITE 1 PRESIUNI ARMONICE POLIFAZICE1857.1. Debite si presiuni armonice bifazice1867.2. Debite si presiuni armonice trifazice186

7.2.1. Montajul in stea a consumatorilor1877.2.2. Montajul in triunghi (delta) a consumatorilor190

7.3. Puterea unui sistem hidraulic armonic trifazic incarcat simetric ..1917.4. Convertori de debite hidraulice alternative193CAPITOLUL 8CURBELE CARACTERISTICE SI PROIECTAREASISTEMELOR HIDRAULICE CU DEBITE ALTERNATIVE2018.1.Curbele caracteristice pentru sistemele hidraulice bifazice2018.1.1. Turatia motorului hidraulic bifazic2058.1.2. Turatia motorului hidraulic bifazic sub sarcina2078.2.Curbele caracteristice pentru sistemele hidraulice trifazice2138.2.1. Turatia motorului hidraulic trifazic2138.2.2. Turatia motorului hidraulic trifazic sub sarcina215CAPITOLUL 9DEBITE IN CONDUCTE LUNGI223

9.1. Debite alternative in conducte lungi2239.2. Conducte uniform incarcate 2479.3. Transmisia de unde in resorturi metalice2549.3.1Capacitatea condensatorilor,tinand seama de inertia resortului2579.3.2Debitele sonice in conducte cu sectiune neuniforma2609.4.Metoda grafo-analitica pentru calculul debitelori presiuni lor sonice in conducte~> * ACAPITOLUL 10ZO'4> v *.i^ if n- .-*^ '** l

DEBITE SONICE IN CONDUCTE LUNGITINAND SEAMA DE FRICTIUNE'27310.1. Influenta frictiunii asupra debitelor sonice in conducte lungi.27310.2. Influenta schimbarii frecventei in conducte lunei?ri10.3. Stabilitatea ..'.'.'.'.''29010.4. Pierderile de putere in liniile rezonante .29110.5. Rezonante critice . . . 292 CAPITOLUL 11DEBITE SONICE DE INALTA FRECVENTA30111.1. Aspecte teoretice privind debitele sonice de inalta frecventa ...30111.1.1. Linii de transmisie cu sectiune variabila30111.1.2. Conducte de lungime infmita31711.1.3. Conducte conice de lungime infmitacu generatorul in apropiere de varf3|gCAPITOLUL 12LINII INCARCATE32512.1. Aspecte generale legate de liniile incarcate325CAPITOLUL 13MOTOARE SONICE34113.1. Teoria deplasamentelor34113.2. Consideratii generale privind motoarele sonice34413.3. Motoare sonice sincrone351

13.3.1. Motoare sonice sincrone monofazate35113.3.2. Motoare sonice sincrone polifazate35313.4.Motoare sonice asincrone35613.4.1. Motoare sonice asincrone polifazate3564

r.13.4.2. Motoare sonice asincrone monofazate36213.5.Motoare cu colector36513.5.1. Motor cu colector, cu conexiuni in paralel36813.6. Redresarea debitelor sonice polifazate37313.7. Componentele sistemelor sonice37813.7.1.Motoare sonice37813.7.1.1. Motoare sonice sincrone37813.7.1.2. Motoare sonice asincrone38213.7.1.3. Motoare cu colector38513.7.2.Generatoare sonice38713.7.2.1. Generator trifazat cu pistoane antagonice38713.7.3.Pompe sonice38913.7.3.1.Pompe cu deplasament fix39013.7.3.1.1. Pompa cu membrana39013.7.3.1.2. Pompa sonica volumetrica39113.7.3.1.3. Pompa sonica fara supape39313.7.3.2.Pompe sonice cu deplasament variabil39413.7.3.2.1. Pompa sonica cu piston,cu deplasament variabil39413.7.4. Conductele de lucru si dispozitive de inchidere39513.7.5. Condensatoare sonice39613.7.6. Transmiterea impulsurilor de forta prin lichide39713.7.7. Ciocan sonic40113.7.8. Sistem sonic de pompare401CAPITOLUL 14CONSIDERATE TEORETICE PRIVIND TEORIAREZONATOARELOR MECANICE40314.1. Oscilatii libere41014.2. Oscilatii continue de amplitudine maxima41214.3. Modificatori de presiune. Reductori si amplificatori425CAPITOLUL 15UTILIZAREA SONICITATII LA COMANDA SUPAPELOR SI A INJECTIEI DE COMBUSTIBIL LA MOTOARELE CUARDERE INTERNA431CAPITOLUL 16REZULTATE ALE APLICARII SONICITATII LA ARDEREACOMBUSTIBILILOR4435

CAPITOLUL 17449449 454 471CONVERTORUL-17.1. Pre7eniarc gencrala17.2. Consiruc|ie $i func|ionare17.3. Tralare matcmatica elcmeniara483 513517CAPITOLUL 18API JCA "fll

Considcratii privind propagarca curcntilor sonici pe linii lungiincarcate i aplicajia la lixiiilc electricc analoge celor soniceINGINERUL GOGV CONSTANT 1NESCULa 40 de ani dc la aparitia Teoriei Sonicitatii541ACADEMIA ROMANA - $edinja din 14 noiembrie 1919Conferinta d-lui Ing. GOGU CONSTANTINESCUSTIINTA SONICA 1APLICATR-INILE EIConfcrinja I - Dccembrie 1919 555STIINTA SONICA $1APLICATIUNILE EIConferinta II - Ianuarie 1920 571IJsta brcvetelor lui Gogu CONSTANTINESCU 587-Lista simbolurilor i notatiilor ulilizale 603BIBLIOGRAF1E 607

FOREWORDThe present book was elaborated in honor of Gogu Constantinescu, the most famous Romanian inventor (317 inventions), and one of the world's greatest inventive minds. The book is also a commemorative celebration of 125 years his birth.Our aim was to give the essential of his ideas, while outlining the great valences of implementation and further developing of his patented inventions.Gogu CONSTANTINESCU was among the world's brilliant minds whose ideas traveled much beyond his time and his physical environment, and that still maintain their applicability and inventiveness. The authors also intended to solve and present in an accessible way the sonicity founder's ideas, while transposing the "Sonicity Theory" in a modern technical language, used nowadays in hydraulic drives. This is very necessary, because Gogu Constantinescu himself believed that: "The law of sonic friction and the law of resistances in electricity corresponded by accident. The basic formulas being the same in both sciences, it was easy for me to copy them, as same as taking them from a dictionary; I took an electrical property and I translated it for the new science. This is how I did for motors, resonators, and with all properties demonstrated in electricity that could be applied in sonicity: an electric resonator which discharges sparks corresponds to a sonic hammer which unloads sparks on the anvil". That led to a difficult understanding of the mentioned phenomena. In the same time, wc tried to completely make the necessary deduction of all the formulas of all studied phenomena, trying in the same time not to alter the thinking of sonicity's founder.Why is this monograph imperative now?It is well known that nowadays, electrical drives and their processing technique, computerized management of systems and processes are very widely spread, because of the facility to transmit and process electrical signals. Nevertheless, in hydraulic equipment, the maximum "pressure"achieved with the help of electrical drives, cannot exceed (15-20) -10 Pa; therefore, the only solution for average and above average input drives is a hydraulic one, which stands out because of the fact that the pressure canexceed (300-400) 105 Pa. Also the power density of a hydraulic unit can be around 40 times greater than that of an electrical drive. In other words, at the same power, a hydraulic motor is about 40 times reduced in weight and volume than an electric one. A disadvantage of contemporary hydraulic7

drives, is the large volume of oil used, being known the fact that the oil accumulation tank of a stationary hydraulic installation, has a volume at about 3-5 times greater than the nominal flow used. Sonic drives permit an optimal use of the advantages given by the facility of transmitting and processing electrical signals with those from sonic drives of great power and efficacy, which leads to the possibility of elimination of the biggest components of an classical hydraulic system (hydraulic tanks, pressure regulation valves, flow control valves etc.), the resulted drive being a very economic one.The first part of this treaty presents an illustrated review of the great personality of Gogu Constantinescu and some of his works, as well as his unimpeachable transition in this life. This was possible mainly due to a very profound work of his son, Ian CONSTANTINESCO [15], which we thank using this way, for his consent and for providing some articles published by him. Being the primary source, this material can be considered a reference for its veridicity. The scientific part starts with the presentation of the basic principles of sonicity, the presentation of the phenomenology of transmitting energy through the sonic waves, defining the main relations and principles which characterize the phenomena from a mathematical point of view, by utilizing a modern and up-to-date language, specific to modern hydraulic drives. There are defined and inserted original aspects concerning pressure waste and the symbols proposed.It is necessaiy to mention that the sonicity's theory brings forward the vision concerning classical hydraulic and pneumatic drives in other terms, which become a particular case of sonical drives (the case in which the momentary flow is equal with its amplitude, so it is constant).Lately, energy transmission by fluids is very dynamic, with direct and profound implications in theoretical approach domain, and also in practical one.Few years ago, notions like: hydrologistors, servovalves, etc. were considered novelties, nowadays these notions are used by every fluidic apparatus producer.It is necessary to underline that by the notion of fluid, as a mean of energy transmission, we understand liquids (oil, water) and gases (air, and other gases).So far, most of the fluid drive systems are based on a continuous development limited in time, given by the consumer's requests and by the used fluid volume, reason why we can call them "with integral flow". This can be continuous or variable in time (with continuous evolution, discontinuous or stochastic). Keeping that in mind, an analogy with continuous current electrical drives can be drawn.Integral flow drives request the presence of a tank (for fluids a hydraulic tank, and for gases, buffer tanks), which can generate the 8

necessary power with the help of the liquid pumps for fluids and compressors for gases. These powers represent the flow and the pressure that can be used at other parametrical level by the linear, oscillating and rotating actuators.For this, a whole series of command and auditing elements is needed, through which we can meet consumer's requests concerning the level of fluidic signal. The processing can be done in a proportional logical binary system (and/or) with modern or classical systems, but with a low relative effectiveness (under 18% for the drives utilizing gases, and to a maximum of 36% for liquid drives).These losses are due to the fact that the liquids flow through pipes, drains, and apparatus with relative high speeds, frequently suffering changes in diameter, sense and flow directions, in a laminar regime, but most of the times in a turbulent one.The merit of approaching the theoretical basis and practical applications of energy transmission in liquids considering their compressibility, was the Romanian scholar Gogu CONSTANTINESCU, which performed his scientific researches in the Coniston laboratory within British Admiralty, managing to elaborate the so called "sonic's theory".It is necessary to mention that, in our vision, this is a particular case of power transmission through "displacement". This means that the liquid doesn't flow in a continuous mode from the generator to the actuator, but it has an harmonic evolution in time, having different frequencies and wave lengths.This drive can be alternative, when the flow evolution is harmonic, the volume of the fluidic column being much smaller than the equivalent volume which permits taking over the volume variations produced by the generator.If the fluidic column's volume is big enough to permit taking over in a relatively closed chamber, through compressibility, the volumic variation produced by the fluidic generator, we have to deal with a drive with sonic displacement.This type of displacement drives are differentiated by the lengths of the waves of the alternative flow, produced by the frequency of rotation of the generator, and in sonical drive case, by the lengths of waves of the developed pressure wave, through which the energy is transmitted and which takes into consideration the propagation speed inside the fluid (for air, approximately 340 m/s, and for water and oil, approximately 1400 m/s).Starting from this concept, we can obtain using clcctrotechnical terminology, synchronous drives, asynchronous, mono, tri and poliphasical drives, using a very small volume of pure fluid which in many cases can be water, and we manage to eliminate the regulation and command apparatus9

of the flow and pressure parameters, by transferring them into the modern field of automatic commands.If the classical drives permit to easily obtain linear motions, the displacement drives can easily produce continuous or intermittent rotating motions that can be transformed in linear motion if required.The present work tries to reveal, based on theoretical and practical means, some particular aspects concerning this old and yet so new way of energy conversion, which allows small built volumes, cheap fluids, reduced pollution, smaller costs, great flexibility and a much improved efficency.The above considerations are outlined in the Synoptic Scheme (pg. 11).The equations that define energetical parameters such as flow and pressure can have a general form like:n -n kAQi - Uamax ' J \st)n - n f(?t APi PamaX J^,S)where f{si) is a stochastic function, and f{st,s) is a load dependent stochastic function.If f{st) and f{st,s) have harmonic evolutions we deal with alternative drives, or sonic drives, and if those functions have unit values, we deal with classical drives.1. Hydro-pneumatic classical drives are similar to electrical drives in continuous current.2. Hydraulic drives with alternative sonical flows are similar electrical drives in alternative current, mono, bi, tri and pohphasic.The concept of sonicity allows unexpected applications and development of pneumatic and hydraulic drives.The present work defines and analyzes the influence that capacity, inertia, friction and losses, have on the sonic flows, discusses their combined effects, by using adequate symbols and vector diagrams.Theoretical considerations are followed by practical examples that analyze the issue of kinetic and potential energy involved, in the sonic transmission phenomena.The book presents the essential power transmission in harmonic flows systems, extending to considerations on polyphasic harmonic flows and pressures. The design and the characteristic curves of hydraulic drives with alternative flows are presented, from the analytic and graphical point of view.10

WITH OILWITH WATERWITH OTHER GASES

WITH "INTEGRAL" FLOWWITH "DISPLACEMENT"

.}SONIC

CONTINUOUS

HYDRO - PNEUMATIC DRIVESWITH AmVARIABLE FLOWALTERNATIVE

WITH OTHER LIQUIDS

STOCHASTIC

SYNCHRONOUS

BIPHASKD

MOHOPHASEDSynoptic table on the fluid drives

TRI PHASED

POLITHASED

A substantial part is devoted to the flows in long pipes, pictured with particular examples and with graphic-analytical methods of analysis, to the aspects concerning the influence of the pressure over the sonical flows in long pipes, the sonical flows of high frequencies, as well as the loaded lines and also to the practical aspects which derive from sonicity's theory.In the end of the treaty there are reproduced the two conferences sustained by Gogu CONSTANTINESCU, in 1919 and 1920, at the "Bridges and Roads National School" from Bucharest, and at Romanian Academy in 1919, as well as a special article, written by Eng. George St. ANDONE, on the occasion of 40 years anniversary since the publication of "Sonicity's theory".For approximately two decades, the Hydraulic and Pneumatic Drives staff inside the Machines Tools and Industrial Robots Department from Technical University of Cluj-Napoca, we managed to solve aspects concerning the power transmission through pressure waves. Five doctoral theses where completed, whose authors are: Dr. Eng. Mohammad KHADER (Jordania), Dr. Eng. Valentin SACEANU, Dr. Eng. loan-Lucian MARCU, Dr. Eng. Ioana DENES POP, Dr. Eng Carmen BAL. They managed to accomplish mono, bi and triphasic, synchronous and asynchronous sonic motors and drives, as well as sonical heating.We succeeded to materialize some step-by-stcp universal motors, which, by a very simple design, can accomplish stcp-by-step linear, rotating and oscillating motions, and the sonical heating.These systems permit to obtain asynchronous revolutions, depending on the generator's revolutions. The asynchronous motor can work mono and biphasic with asymmetrical phases, and triphasic with balanced phases.They can offer the facility to work step-by-step at constant or variable frequencies, giving the possibility to meaningful reduce the output revolution without any additional mechanical element, being able to replace reducers with their driving systems, thus reducing extra cost and heavy weights. Through the utilization of synchronous and asynchronous drives, we can obtain greater shifting speed of the mobile component of the robot utilizing synchronous drive and an increased positioning precision utilizing asynchronous drive. This way a hybrid was obtained, which combines the qualities of electrical drives with those of pressure waves.The solutions are to be patented and we hope to open new directions concerning the transmission of average and above average powers, starting from small sources of energy.In honor of the personality of Gogu CONSTANTINESCU, the Romania's Society of Inventors set an order of distinction called Gogu CONSTANTINESCU, which will be awarded to our greatest inventors.12

CAPITOLUL 1INTRODUCERETratatul de fa{a este un omagiu adus celui mai mare inventator roman (317 invcntii) si uneia dintre cele mai stralucitc minti ale lumii, Gogu CONSTANTINESCU.El cste totodata o incercare de a contribui la cunoasterea esenjei si man lor valenje de implcmcntarc, utilizare si dezvoltare a ideilor remarcabilului nostru compatriot fiind dedicat anivcrsarii a 125 de ani de la rsasterea sa.Gogu CONSTANTINESCU a fost unul dintre acele minfi geniale, ale carui idei au devansat cu mult timpul existenjei sale fizicc, dar care astazi isi pastreaza actualitatea, surprinzand prin acuratete, inventivitate si aplicabilitate.Lucrarea prezenta incearca sa trateze intr-un mod cat mai accesibil ideile intemeietorului sonicitatii, cu referirc la solutiile hidraulicc, "transpunand" limbajul folosit in "Teoria Sonicitatii" [14] intr-unul modern, adecvat celui practicat astazi in actionarile hidraulicc. Aceasta este absolut necesara, deoarece insusi Gogu CONSTANTINESCU spunea [14]: "A fost o intamplare ca legca de frictiune sonica s-a potrivit cu legea rezistentci in electricitate. Formulele elementare fiind astfel identice in ambele stiinte, mi-a fost usor sa copiez din electricitate ca dintr-un dic{ionar; am luat o proprietate electrica si am tradus-o in noua stiinta. Asa am facut cu motoareie, cu rezonatoarele si cu toate proprietatile demonstrate in electricitate, pe care am putut sa le traduc in motoare sonice: unui rezonator electric care descarca scantei ii corespundc in sonicitate un ciocan sonic care descarca lovituri asupra nicovalei". Aceasta, a condus la o intelegere dificila a fcnomenelor enuntate. Totodata s-a cautat sa se faca deducerile in totalitate a rela|iilor si fenomenelor studiate, inccrcand in acclasi timp sa nu se altereze in nici un fcl gandirca si cxprimarile parintelui teoriei sonicitatii.De ce este necesara aceasta monografie acum?Dupa cum se cunoaste, astazi au capatat o mare extindcrc actionarile electrice, tehnica de prelucrare a acestora, conduccrca computerizata a proceselor si sistcmclor, datorita usurintei de prelucrare si transmitere a semnalului electric.Totusi, vorbind in limbaj hidraulic, "prcsiunea" maxima realizabila in actionarile electrice nu poate depasi 15-20E+05 Pa, deci implicit, pentru actionarile dc puteri medii si mari, singura solutie de actionare este cea13

Tratat de teoria sonicitatii - Prof. univ. dr. ing. loan 1. POPhidraulica, care se dctacaza net prin aceea ca presiunea poate depasi 300-400E+05 Pa. Totodata, densitatea de putere a unei unitati hidraulice poate i depasi de 40 dc ori pe cea a unei actionari electrice. Altfel spus, la aceeasi putere, un motor hidraulic este de aproximativ 40 de ori rnai redus ca volum si greutate fata de unul electric.Un alt dezavantaj, legat de data aceasta de actionarile hidraulice actualc, il constituie volumul mare de ulei folosit, fiind cunoscut faptul ca un rezervor de stocare a uleiului unei instalafii hidraulice stationare, are un volum de 3-5 ori mai dccat dcbitul nominal utilizat.Actionarile sonice permit o imbinare optima a facilitafilor oferite de usurinta prelucrarii semnalelor electrice (de encrgic redusa) cu actionarile sonice de mare putere si randament, care dau posibilitatea eliminarii celor mai mari parti ale unui sistem hidraulic clasic (rezervoare hidraulice, ventile de reglare a presiunii, debitului, caii etc.), rezultand o acttonare care combina optim oportunitatile oferite de tehnica prelucrarii semnalelor de mica encrgic si actionarile sonice compacte, cu randament ridicat, cu volum redus, deci foarte economice.In prima parte a tratatului este abordata si ilustrata personalitatea si o parte din realizarile lui Gogu CONSTANTINESCU, precum si trecerea sa impetuoasa prin aceasta lume. Aceasta a fost posibila in primul rand dalorita unci lucrari de suflet a fiului sau Ian CONSTANTINESCO [15], caruia ii muitumim pc accasta cale pentru acordul sau pentru utilizarea materialelor publicate de domnia sa. Fiind sursa primara, acest material poate fi considerat un ctalon in ceea ce priveste vcridicitatea sa.Partea pur stiinfifica incepe prin prezentarca principiilor elementare ale sonicitatii, prin prezentarca fenomenologiei transmiterii cnergici prin unde sonice, definindu-se apoi principalele relatii si concepte care imbraca fenomenul din punct de vedere matematic, prin utilizarea unui limbaj stiintific modern si actual, specific actionarilor hidraulice modcrne. Sunt definite si inserate aspecte originale privind pierderile de prcsiune si simbolistica propusa sprc utilizare.Trebuic menfionat aici ca teoria sonicitafii pune sub o cu totul aha lumina viziunea asupra actionarilor hidraulice si pneumatice clasicc, care devin un caz particular al actionarilor sonice (cazul in care debitul instantaneu este egal cu amplitudinea acestuia, deci este constant).Transmiterea encrgiei cu ajutorul fluidelor s-a dovedit cu precadere in ultimul timp deoscbit de dinamica, cu implicafii dirccte si profunde atat in domeniul abordarilor teorctice, cat si a realizarilor practice.Daca pana acum cativa ani nofiuni ca: hidrologistori, acp'onari proportionale, servoventile etc., erau considerate noutati de ultima ora, ele au intrat in practica curenta i in rcalizariic frecvente ale producatorilor de aparatura pentru fluide.14

Tratat de teoria sonicitaiii - Prof. univ. dr. ing. loan I. POPTrebuie sa precizam ca prin fluide, ca si mcdiu dc transmitere a puterii, in^elegcm lichide (ulei, apa, altcle) si gaze (aer, alte gaze).Pana in prczent covarsitoarea majoritate a sistemelor de actionare cu fluide se bazeaza pe o evolutic continua intr-un timp limitat, dat de ccrinjele consumatorilor, a volumului de fluid utilizat, motiv pentru care putem denumi aceste actionari "cu debit integral". Acesta poatc fi continuu sau variabil in timp (cu evolufie continua, discontinue sau stocastica). Tinand cont de acestea sc poate face o analogie cu actionarile elcctrice dc curent continuu.Acfionarile cu debit integral presupun existenta unui rezcrvor dc fluid (pentru lichide rczervor hidraulic, iar pentru gaze recipicnte tampon), care sa generczc prin intcrmediul pompelor pentru lichide sj compresoarclc pentru gaze puterea necesara, sub forma de debit i presiune, care sa poata fi utilizata la alti parametri de catre actuatorii liniari, oscilanti sau rotativi.Pentru aceasta este nevoie de o scrie intrcaga de elemente de comanda si control care sa realizcze aduccrea semnalului fluidic la nivelul solicitat de catre consumatori. Aceasta prelucrare se poate face in sistem logic binar si/sau proportional cu sisteme clasicc sau modeme, dar cu un randament relativ scazut (aprox. 18 % pentru actionarile cu gaze si maxim 36 % pentru acfionarile cu lichide).Aceste pierderi se datoreaza in principal faptului ca fluidcle curg prin conducte, canale, aparatc etc., cu viteze rclativ ridicate, suferind frecvente schimbari dc sectiuni, sensuri sj direcfii dc curgere in regim laminar, dar de ecle mai multe ori turbulent. Marca majoritate a energici este disipata sub forma dc caldura.Datorita multimdinii de aparate si elemente care concura in mod direct sau indirect in prelucrarea puterii transmisc, constructive finale sunt de regula scumpe i complicate. Mai mult, la acfionarile cu lichide este necesara folosirea de ulciuri care prezinta pcricol de inflamabilitate, sunt scumpe si deoscbit de poluante.Sistemele enumerate, pe care lc vom numi "clasicc", permit transportul masic al fluidului (cu pierderile aferentc), prezentand ca i dczavantaje: o masa marc de fluid, de regula poluant, incinte de stocare costisitoare si elemente de rcglaj complcxc si scumpe.In toate cazurile mentionate pana acum comprcsibilitatea fluidelor este cunoscuta dar nu este luata in considerare in mod constant, desi aceasta comportarc este cunoscuta chiar inainte de aparitia actionarilor cu fluide "clasice".Mcritul abordarii pentru prima data, atat din punct dc vedere teorctic cat si practic, a transmitcrii energiei prin considcrarea prcponderenta a compresibilitafii fluidelor ii revine savantului roman Gogu CONSTANTINESCU, care si-a realizat cercetarilc in laboratorul din15

Tratat de tcoria sonicitgtij

- Prof. univ. dr. ing. loan I. POP

Coniston al Amiralifatii Britanice, dezvoltand asa numita "teorie a sonicitatii".Aici trebuie mentionat faptui ca\ in viziunea noastra, aceasta teorie este un caz particular al transmiterii puterii prin "deplasament". Aceasta inseamna ca fluidul nu curge continuu de la generator spre actuator, ci el are o evolutie armonica in timp, avand frecvcnfc si lungimi de unda diferite.Aceasta acfionare poate fi altemanta, cand evolup'a debitului este armonica, volumul coloanei fluide fiind mult mai mic decat volumul echivalent necesar care sa permita preluarea in totalitate de catrc coloana dc fluid prin compresibilitatea acesteia o variatie de volum produsa de generator.Daca volumul coloanei de fluid este destul de mare ca sa permita preluarea intr-o incinta relativ inchisa, prin compresibilitatc, a variap'ei volumice produse de generatorul fluidic, avem de-a face cu o acfionare cu deplasament sonic.Aceste acp^onari cu deplasament se diferentiaza in funcp'e de lungimile de unda ale debitului alternant, produse de frecventa de rotatie a generatorului (pentru dcbitele alternante), iar in cazul acponSrii sonice de catre lungimea de unda a undei de presiune dezvoltate, prin care se transmite energia prin fluid si care fine cont de viteza de propagare in fluidul utilizat (pentru aer aproximativ 340 m/s, iar pentru apa si ulei aproximativ 1400 m/s).Pornind de la acest concept se pot obfine, folosind terminologia din electrotehnica, acponari sincrone, asincrone, monofazice, bifazice, trifazice si polifazice, in conditiile folosirii unui volum foarte mic de fluid nepoluant, care in multe cazuri poate fi apa, eliminarea aparatelor individuale de reglare si comanda a parametrilor de debit si presiune, prin transfcrarea acestora in domeniul atat de modem al comenzilor electronice si computerizate.Daca actionarile clasice permit foarte usor obtinerea de miscari liniare, actionarile cu deplasament realizeaza foarte usor miscari dc rotajie continue sau intermitentc, care pot fi transformate, dac2 este cazul, in miscari liniare.Prczenta lucrare incearca sa desluseasca, atat prin mijloacc experimcntale cat si teoretice, unele aspectc intime legate de aceasta atat de veche si atat de noua modalitate de conversie a energiei, care confera volume construite reduse, fluide ieftine, poluare redusa, costuri mult micsorate, interfata foarte lejera si ieftina cu tehnica de calcul, flexibilitate deosebita si randamente mult imbunatatite.Cele prezentate mai sus pot fi analizate sugestiv cu ajutorul tabloului sinoptic urmStor.16

Tratat de teoria sonicitatii - Prof. univ. dr. ing. loan I. POP

wob-i

wowHIIIW

y R

o EQWQ U2

I

w oIIN8iiS7ro = "="7 V (? mar ' *** + 1051 1 Ml1

no5i-io6 Re, Res

Figura 4.12. Curbele X =f(Re)

Q. 1&P*Xanax ~Vuoai'SiApte^Q.^,Figura 4.13. Varia\ia debitului, presiunii p afazei in cazul rezislenfei hidraulice datorate fricfiunii4.4.6.2. Caderea de presiune datorata inertiei fluidului in miscareIn miscarea sa, masa fluidului poseda o anumita inertie, care...dvdetermina forta F, proportionala cu masa i accclerajia impnmata, ,dt(legea lui Newton F = ma).105

Tratat de teoria sonicitatii - Prof. univ. dr.ing. loan I. POP

Deci inertia este o proprietate care depinde de masa in miscare.Astfel, daca se considers o masa de fluid {inuta in miscare de o presiune care actioneaza pe o suprafata S, normala pe dircctia miscarii, se poatc scrie:

dv4.73F = S-ApLi=m

dtunde: Apu - variatia de presiune inertiala (numita si inductiva, datorita similitudinii fenomcnului cu ecl de inductie electromagnetic^). Relatia Q = v S, poale fi scrisa sub forma:dQ = dV-S4.74sau:4.75

S

Inlocuind (4.75) in (4.73) se obtine:

m dQsau:

S dtF~S-Apu=~"-f4.76

An = -^PLi S2 dt

4.11

m G4.78S2 g-S2Dcfinim coeficientul de inertie sau inductanta hidraulica Ls, ca:

unde:

G = m-g4.79g - acceleratia gravitationala.Asadar (4.77) devine: sau:

dt4>l/ = h JpLrdtUdQ,=

4.80

Ecuajia (4.80) stabileste legatura dintre prcsiunea sonomotrice care lucreaza asupra unci mase m si debitui dQt creat de miscare, masa fiind presupusa legata rigid de un piston care se misca intr-un cilindru de sectiune S.106

'ratat de teoria sonicitajii - Prof. univ. dr. ing. loan I. POP

O coloana de lichid cu lungimea / va avea o inertie (inductanta)ca:ri4.81g-srsre:

Ls*

G=yV=ySl

v- greutatca specifica a lichidului [daN/m];/ - lungimea coloanci [m];5 - sectiunea interioara a conductei [m~].Daca in relajia (4.80) tinem cont ca estc vorba despre un debit , (relajia 4.73), aceasta devine:

-*1

, d(Qi) . d\Qamax-sm(a>t + -Ls-Qsir-cosa + j -y/-0)Ls -p$ir-sina pSig=Psir-(cosa~o)-y/-Ls -sina)+j-QSir -(sina+Xj/co-L^ -cosa) 9.76241

Tratat dc teoria sonicitajii - Prof. univ. dr. ing. loan I. POPnotand cu tg8=y/-a-Ls, relatia (9.76) devine:Psig = PSir "(cos=\l(PSir-cosa)2 +

100-0,99.89pSis^m2+=7' 936+5,0625 =35

= Vl941,0625 =44,07 kgf/cm2 = 4,323267 106 PaSe obscrva ca presiunca sonomotrica la receptor este mai mult decat httul accleia de la generator.HL2. CONDUCTE UNIFORM iNCARCATEEcuatiile difercntiale pentru o conducta ordinara |inand seama de erria si capacitatea lichidului sunt date de relatiile (9.7) si (9.8):=j-6)Cs-~p9-88,^- i a muxaxd~n- fife

Pamax-=jcoLs-Qai

Considerand o conducta avand un numar uniform de ramificatii aribuitc de-a lungul ei, care furnizeaza debite cgale la un numSr oarecare de receptoarc.Varia^ia presiunii pamax nu se datorcaza numai compresibilitatii ichidului, ci numai unui debit distribuit pe unitatea de lungime care s-a otat cu q.Rela|iile (9.88) in acest caz devin:JQamax=J-vCs-~pcimax-dx+qu-dx9.90^^=J-oyCs~Pamax+qufife9.91aa acest caz presiune sonomotrica fund data de relatia (9.89):-2f^-J-coLsQamax9.92dx247

0101010201014848010100010007700420530202010201010101010191010100010000000023230210101010100202020202010504050101161601

Tratat de teoria sonicit5tii - Prof. univ. dr. ing. loan I. POPDiferentiind cele doua rclatii (9.92) si inlocuind in reiatia (9.9I| rczulta:dxd Pa^^j^.l^dQajn^dx'

=jo)-Ls-\j-co-Cs-pamax+qud2~Pa,

d2Pa,:2 1,2dx2

-=j -co -Ls-Cs-pamax+j--q-Is = ., WbJs.., j-q248Mco -Ls-Cs (o-Cs

Tratat de tcoria sonicitatii - Prof. univ.dr.ing. loan I. POP%.

J-St

Z = Pa,f Famax co-c"s

a max

d2z d2~pHx2' dx2

dInlocuind Pamax din relatia (9.93) si pe "pamax din relatia (9.94)dx:m:

jco-qu-Lstm-Lsq-/Jnnlta ecuatia (9.94) care devine:

\

=-fi2z+jco-Ls-qu-j-CQ-Ls-qu

,2_+ .,-0

. ...-rezoivarea ecuatiei difcrentiale de ordinul doi, obtinem solujiuc z = 0 si = - if, deci putcm sa scriem solutia trigonometric a ecuatiei:

z=A cos\n x)+B sin(ji x)

9.96

In acest caz sc determina prcsiunea sonomotrica si dcbitul in acest prin inlocuirea solutiei (9.96) in relatia (9.95):JW = A-cos{vx)+B-sm{vx)+^L-9.97coCr

Qa max = A ^Osiji x)+ 5j Sw{m x)

9.98

Pentru determinarea constantelor A,A\,B$\B\ se ia originea lui x la apatul cu receptorul, astfel ca relatiile (9.97) si (9.98) devin: Pentru x = 0:tSu(O-Cs_Pamax

J'Qu CO-Csezulta:fj.gA = Pa

9.99

A=Qa,

249

Tratat de teoria sonicitatii - Prof. univ. dr. ing. loan I. POPDifercntiind rclatiilc (9.99) si tinand cont de rclatiilc (9.92) si (9.90):

im~,S= J-COls-Qamax=ft\-A-sirAji-x)+B-cos(ti'xft9.! :dOJ^L=j.