{"id":1549,"date":"2025-04-29T19:10:26","date_gmt":"2025-04-29T19:10:26","guid":{"rendered":"https:\/\/www.dioda.ro\/blog\/?p=1549"},"modified":"2025-04-29T19:11:03","modified_gmt":"2025-04-29T19:11:03","slug":"sisteme-de-detectare-a-flacarii-in-centralele-termice-pe-gaz-modele-mai-vechi","status":"publish","type":"post","link":"https:\/\/www.dioda.ro\/blog\/centrale-termice\/sisteme-de-detectare-a-flacarii-in-centralele-termice-pe-gaz-modele-mai-vechi\/","title":{"rendered":"Sisteme de detectare a flacarii in Centralele termice pe gaz (modele mai vechi)"},"content":{"rendered":"<header>\n<p data-type=\"subtitle\">Detectoarele de flac\u0103r\u0103<\/p>\n<\/header>\n<p>Sistemul de control al centrale pe gaz utilizeaz\u0103 dispozitive de detectare a fl\u0103c\u0103rii pentru a asigura aprinderea \u00een siguran\u021b\u0103 a fl\u0103c\u0103rii pilot \u0219i\/sau a arz\u0103torului principal. Cunoa\u0219terea modului \u00een care func\u021bioneaz\u0103 detectoarele de flac\u0103r\u0103, unde sunt aplicate \u0219i cum interac\u021bioneaz\u0103 cu alte controale este important\u0103 pentru \u00een\u021belegerea circuitului general de siguran\u021b\u0103 a fl\u0103c\u0103rii. Orice flac\u0103r\u0103 pilot care este supravegheat\u0103 de o form\u0103 de control primar de siguran\u021b\u0103, conceput pentru a detecta prezen\u021ba acesteia \u00eenainte ca gazul s\u0103 fie admis \u00een arz\u0103torul principal, este denumit\u0103 pilot verificat. Urm\u0103torii detectori de flac\u0103r\u0103 sunt utiliza\u021bi \u00een mod obi\u0219nuit cu sistemele de aprindere cu flac\u0103r\u0103 pilot:<\/p>\n<ul>\n<li>Termocuplu<\/li>\n<li>Termopil\u0103<\/li>\n<li>Tij\u0103 de flac\u0103r\u0103 &#8211; Electrozi detectare de ionizare<\/li>\n<\/ul>\n<h1 id=\"chapter-165-section-1\" class=\"section-header\">Termocuplu<\/h1>\n<p>Termocuplul este alc\u0103tuit din dou\u0103 metale diferite, unite la un cap\u0103t, numit jonc\u021biune cald\u0103. Cap\u0103tul opus, care nu este unit, se nume\u0219te jonc\u021biune rece (Figura 1). Este important ca numai<span id=\"MathJax-Element-1-Frame\" class=\"mjx-chtml MathJax_CHTML\" style=\"box-sizing: border-box; color: #000000; display: inline-table; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 18.18px; font-size-adjust: none; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;\" tabindex=\"0\" role=\"presentation\" data-mathml=\"&lt;math xmlns=&quot;http:\/\/www.w3.org\/1998\/Math\/MathML&quot;&gt;&lt;mstyle displaystyle=&quot;true&quot; scriptlevel=&quot;0&quot;&gt;&lt;mfrac&gt;&lt;mn&gt;3&lt;\/mn&gt;&lt;mn&gt;8&lt;\/mn&gt;&lt;\/mfrac&gt;&lt;\/mstyle&gt;&lt;\/math&gt;\"><span id=\"MJXc-Node-1\" class=\"mjx-math\" aria-hidden=\"true\"><span id=\"MJXc-Node-2\" class=\"mjx-mrow\"><span id=\"MJXc-Node-3\" class=\"mjx-mstyle\"><span id=\"MJXc-Node-4\" class=\"mjx-mrow\"><span id=\"MJXc-Node-5\" class=\"mjx-mfrac\"><span class=\"mjx-box MJXc-stacked\"><span class=\"mjx-numerator\"><span id=\"MJXc-Node-6\" class=\"mjx-mn\"><span class=\"mjx-char MJXc-TeX-main-R\">3<\/span><\/span><\/span><span class=\"mjx-denominator\"><span id=\"MJXc-Node-7\" class=\"mjx-mn\"><span class=\"mjx-char MJXc-TeX-main-R\">8<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><span class=\"MJX_Assistive_MathML\" role=\"presentation\">38<\/span><\/span>la<span id=\"MathJax-Element-2-Frame\" class=\"mjx-chtml MathJax_CHTML\" style=\"box-sizing: border-box; color: #000000; display: inline-table; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 18.18px; font-size-adjust: none; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;\" tabindex=\"0\" role=\"presentation\" data-mathml=\"&lt;math xmlns=&quot;http:\/\/www.w3.org\/1998\/Math\/MathML&quot;&gt;&lt;mstyle displaystyle=&quot;true&quot; scriptlevel=&quot;0&quot;&gt;&lt;mfrac&gt;&lt;mn&gt;1&lt;\/mn&gt;&lt;mn&gt;2&lt;\/mn&gt;&lt;\/mfrac&gt;&lt;\/mstyle&gt;&lt;\/math&gt;\"><span id=\"MJXc-Node-8\" class=\"mjx-math\" aria-hidden=\"true\"><span id=\"MJXc-Node-9\" class=\"mjx-mrow\"><span id=\"MJXc-Node-10\" class=\"mjx-mstyle\"><span id=\"MJXc-Node-11\" class=\"mjx-mrow\"><span id=\"MJXc-Node-12\" class=\"mjx-mfrac\"><span class=\"mjx-box MJXc-stacked\"><span class=\"mjx-numerator\"><span id=\"MJXc-Node-13\" class=\"mjx-mn\"><span class=\"mjx-char MJXc-TeX-main-R\">1<\/span><\/span><\/span><span class=\"mjx-denominator\"><span id=\"MJXc-Node-14\" class=\"mjx-mn\"><span class=\"mjx-char MJXc-TeX-main-R\">2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><span class=\"MJX_Assistive_MathML\" role=\"presentation\">12<\/span><\/span>O por\u021biune (10 mm p\u00e2n\u0103 la 13 mm) a jonc\u021biunii calde este \u00eenc\u0103lzit\u0103 de flac\u0103ra pilot, deoarece cu c\u00e2t diferen\u021ba de temperatur\u0103 dintre jonc\u021biunile calde \u0219i reci este mai mare, cu at\u00e2t tensiunea generat\u0103 este mai mare. Termocuplul genereaz\u0103 aproximativ 25 p\u00e2n\u0103 la 30 de milivol\u021bi (mV), ceea ce este suficient pentru a alimenta electromagnetul dintr-o supap\u0103 de \u00eenchidere de siguran\u021b\u0103 sau un comutator de siguran\u021b\u0103.<\/p>\n<figure id=\"attachment_28\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-28\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-156\" src=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-hot-and-cold-junctions-e1643761014806.jpg\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" srcset=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-hot-and-cold-junctions-e1643761014806.jpg 934w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Thermocouple-hot-and-cold-junctions-e1643761014806-300x169.jpg 300w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Thermocouple-hot-and-cold-junctions-e1643761014806-768x432.jpg 768w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-hot-and-cold-junctions-e1643761014806-65x37.jpg 65w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-hot-and-cold-junctions-e1643761014806-225x126.jpg 225w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-hot-and-cold-junctions-e1643761014806-350x197.jpg 350w\" alt=\"\" width=\"600\" height=\"337\" \/><figcaption id=\"caption-attachment-28\" class=\"wp-caption-text\">Figura 1 Jonc\u021biuni calde \u0219i reci ale termocuplurilor<\/figcaption><\/figure>\n<p>Unul dintre capetele jonc\u021biunii reci este conectat la man\u0219onul exterior metalic al termocuplului, \u00een timp ce cel\u0103lalt cap\u0103t al jonc\u021biunii reci este conectat la un fir izolat din interiorul man\u0219onului exterior (Figura 2). Man\u0219onul exterior este de obicei fabricat din constantan, un metal pe baz\u0103 de nichel \u0219i cupru, care are o rezistivitate constant\u0103 pe o gam\u0103 larg\u0103 de temperaturi. Capetele jonc\u021biunii reci devin cablurile c\u0103tre supapa sau comutatorul de siguran\u021b\u0103. \u00cen mod obi\u0219nuit, termocuplurile au o lungime de 0,5 m, 0,6 m \u0219i 0,9 m, dar modelele sunt fabricate p\u00e2n\u0103 la 1,5 m. Atunci c\u00e2nd \u00eenlocui\u021bi un termocuplu, este important s\u0103 comanda\u021bi unul potrivit.<\/p>\n<figure id=\"attachment_28\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-28\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-157 size-full\" src=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-construction-e1643761561728.jpg\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" srcset=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-construction-e1643761561728.jpg 500w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Thermocouple-construction-e1643761561728-300x202.jpg 300w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-construction-e1643761561728-65x44.jpg 65w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-construction-e1643761561728-225x152.jpg 225w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermocouple-construction-e1643761561728-350x236.jpg 350w\" alt=\"\" width=\"500\" height=\"337\" \/><figcaption id=\"caption-attachment-28\" class=\"wp-caption-text\">Figura 2 Construc\u021bia termocuplului<\/figcaption><\/figure>\n<p>Dac\u0103 flac\u0103ra pilot permanent\u0103 ar trebui stins\u0103, exist\u0103 o \u00eent\u00e2rziere de p\u00e2n\u0103 la 90 de secunde, c\u00e2t timp termocuplul se r\u0103ce\u0219te, \u00eenainte ca valva de gaz s\u0103 se \u00eenchid\u0103. Prin urmare, codul de siguranta in folosirea gazelor stabile\u0219te limit\u0103ri privind utilizarea acestora \u00een func\u021bie de gazul introdus \u00een arz\u0103tor sau de tipul de gaz. De exemplu, aparatele cu o greutate specific\u0103 mai mare dec\u00e2t aerul (cum ar fi propanul) vor avea un timp maxim de r\u0103spuns al fl\u0103c\u0103rii de 20 de secunde. Aceste aparate vor fi echipate cu termocupluri cu r\u0103spuns rapid (Figura 3). Deoarece multe dintre aceste aparate, cum ar fi \u0219emineele, sunt convertibile pentru oricare dintre combustibili, acesta este tipul de termocuplu care este instalat.<\/p>\n<figure id=\"attachment_28\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-28\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-158 size-full\" src=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Fast-response-thermocouple-e1643761642612.jpg\" sizes=\"auto, (max-width: 268px) 100vw, 268px\" srcset=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Fast-response-thermocouple-e1643761642612.jpg 268w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Fast-response-thermocouple-e1643761642612-65x46.jpg 65w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Fast-response-thermocouple-e1643761642612-225x159.jpg 225w\" alt=\"\" width=\"268\" height=\"189\" \/><figcaption id=\"caption-attachment-28\" class=\"wp-caption-text\">Figura 3 Termocuplu cu r\u0103spuns rapid<\/figcaption><\/figure>\n<h1 id=\"chapter-165-section-2\" class=\"section-header\">&#8220;Termopil\u0103&#8221; (traducere &#8220;brutala&#8221; &#8211; mai multe termocuple inseriate)<\/h1>\n<p>Termopile, cunoscute \u0219i sub denumirea de pile de putere sau generatoare pilot, sunt similare termocuplurilor \u0219i genereaz\u0103 electricitate din c\u0103ldura unei fl\u0103c\u0103ri pilot. Intern, acestea constau din mai multe termocupluri unite \u00een serie pentru a genera mai mult\u0103 tensiune. Majoritatea termopilelor constau din 10 p\u00e2n\u0103 la 30 de termocupluri conectate \u00een serie, cre\u00e2nd intervale de ie\u0219ire de la 250 la 750 mV (Figura 4).<\/p>\n<figure id=\"attachment_28\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-28\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-159 size-full\" src=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermopiles-from-top-to-bottom-750mV-500-mV-250-mV-e1643761736484.jpg\" sizes=\"auto, (max-width: 327px) 100vw, 327px\" srcset=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermopiles-from-top-to-bottom-750mV-500-mV-250-mV-e1643761736484.jpg 327w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Thermopiles-from-top-to-bottom-750mV-500-mV-250-mV-e1643761736484-300x207.jpg 300w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermopiles-from-top-to-bottom-750mV-500-mV-250-mV-e1643761736484-65x45.jpg 65w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermopiles-from-top-to-bottom-750mV-500-mV-250-mV-e1643761736484-225x156.jpg 225w\" alt=\"\" width=\"327\" height=\"226\" \/><figcaption id=\"caption-attachment-28\" class=\"wp-caption-text\">Figura 4 Termopile de sus \u00een jos; 750mV, 500 mV, 250 mV<\/figcaption><\/figure>\n<p>Tensiunea mai mare permite termopilei s\u0103 alimenteze circuitul de siguran\u021b\u0103 a combustiei unui aparat \u0219i circuitul s\u0103u de control, at\u00e2ta timp c\u00e2t flac\u0103ra pilot este aprins\u0103. Dac\u0103 flac\u0103ra pilot s-ar stinge, ambele circuite s-ar defecta \u0219i s-ar opri. Termopilele sunt fabricate \u00een dou\u0103 modele, fie cu dou\u0103 fire, fie coaxiale (Figura 5). Stilul coaxial are o conexiune foarte similar\u0103 cu cea a unui termocuplu.<\/p>\n<figure id=\"attachment_28\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-28\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-160\" src=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermopile-types.jpg\" sizes=\"auto, (max-width: 624px) 100vw, 624px\" srcset=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermopile-types.jpg 624w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Thermopile-types-300x134.jpg 300w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermopile-types-65x29.jpg 65w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermopile-types-225x100.jpg 225w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Thermopile-types-350x156.jpg 350w\" alt=\"\" width=\"624\" height=\"278\" \/><figcaption id=\"caption-attachment-28\" class=\"wp-caption-text\">Figura 5 Tipuri de termopile \u2013 Dou\u0103 fire (st\u00e2nga) \u0219i Coaxiale (dreapta)<\/figcaption><\/figure>\n<h1 id=\"chapter-165-section-3\" class=\"section-header\">Electrod de detectare flac\u0103r\u0103<\/h1>\n<p>Multe aparate sunt dotate cu un sistem de aprindere electronic\u0103 pentru aprinderea fl\u0103c\u0103rii pilot \u0219i o tij\u0103 de flac\u0103r\u0103 pentru detectarea acesteia. Tijele de flac\u0103r\u0103 sunt tije metalice cu diametru mic, sus\u021binute de un izolator, al c\u0103rui v\u00e2rf iese \u00een flac\u0103r\u0103 (Figura 6).<\/p>\n<figure id=\"attachment_28\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-28\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-161 size-full\" src=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Pilot-burner-e1643761927894.jpg\" sizes=\"auto, (max-width: 310px) 100vw, 310px\" srcset=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Pilot-burner-e1643761927894.jpg 310w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Pilot-burner-e1643761927894-300x268.jpg 300w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Pilot-burner-e1643761927894-65x58.jpg 65w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Pilot-burner-e1643761927894-225x201.jpg 225w\" alt=\"\" width=\"310\" height=\"277\" \/><figcaption id=\"caption-attachment-28\" class=\"wp-caption-text\">Figura 6 Arz\u0103tor pilot cu tij\u0103 de flac\u0103r\u0103 separat\u0103 \u0219i aprinz\u0103tor cu sc\u00e2nteie<\/figcaption><\/figure>\n<p>Pentru sistemele de aprindere prin sc\u00e2nteie, tija este de obicei fabricat\u0103 din \u201eKanthol\u201d, un aliaj capabil s\u0103 func\u021bioneze la temperaturi de p\u00e2n\u0103 la 2.400 \u00baF (1.300 \u00baC). Nu exist\u0103 \u00eentotdeauna o tij\u0103 de flac\u0103r\u0103 separat\u0103; uneori, aprinz\u0103torul \u0219i tija de flac\u0103r\u0103 sunt combinate \u0219i folosesc aceea\u0219i tij\u0103 pentru a servi ambele scopuri. Pentru sistemele de aprindere cu suprafa\u021b\u0103 fierbinte, \u201eGlobar\u201d, care are o temperatur\u0103 maxim\u0103 de func\u021bionare de 2.600 \u00baF (1.425 \u00baC), poate servi \u0219i ca tij\u0103 de flac\u0103r\u0103.<\/p>\n<p>Func\u021bionarea tijei de detectare a fl\u0103c\u0103rii se bazeaz\u0103 pe principiul ioniz\u0103rii fl\u0103c\u0103rii, prin care ionii se formeaz\u0103 \u00een timpul procesului de ardere. Acest proces de ionizare face ca flac\u0103ra s\u0103 fie un conductor de electricitate cu rezisten\u021b\u0103 ridicat\u0103. Acest fenomen poate fi utilizat pentru a face ca o flac\u0103r\u0103 s\u0103 ac\u021bioneze ca un comutator \u0219i s\u0103 completeze circuitul de detectare a fl\u0103c\u0103rii, permi\u021b\u00e2nd circula\u021bia unei cantit\u0103\u021bi mici de curent ori de c\u00e2te ori este prezent\u0103 flac\u0103ra pilot (Figura 7).<\/p>\n<figure id=\"attachment_28\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-28\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-162\" src=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Electron-flow-through-ionized-flame-e1643762022647.jpg\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" srcset=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Electron-flow-through-ionized-flame-e1643762022647.jpg 473w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Electron-flow-through-ionized-flame-e1643762022647-240x300.jpg 240w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Electron-flow-through-ionized-flame-e1643762022647-65x81.jpg 65w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Electron-flow-through-ionized-flame-e1643762022647-225x281.jpg 225w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Electron-flow-through-ionized-flame-e1643762022647-350x437.jpg 350w\" alt=\"\" width=\"300\" height=\"375\" \/><figcaption id=\"caption-attachment-28\" class=\"wp-caption-text\">Figura 7 Curgerea electronilor printr-o flac\u0103r\u0103 ionizat\u0103<\/figcaption><\/figure>\n<p>Sistemele ini\u021biale dezvoltate care utilizau aceast\u0103 caracteristic\u0103 erau susceptibile la poten\u021biale indica\u021bii false de flac\u0103r\u0103 prin scurtcircuite cauzate de depuneri de carbon care puteau conduce curentul. Sistemul de rectificare a fl\u0103c\u0103rii a fost dezvoltat pentru a recunoa\u0219te diferen\u021ba dintre scurgerile de \u00eenalt\u0103 rezisten\u021b\u0103 la mas\u0103 \u0219i o flac\u0103r\u0103 real\u0103.<\/p>\n<h1 id=\"chapter-165-section-4\" class=\"section-header\">Sistem de rectificare a fl\u0103c\u0103rii<\/h1>\n<p>C\u00e2nd se aplic\u0103 tensiune alternativ\u0103 pe sistemul conductiv de flac\u0103r\u0103 neredificat, prezentat \u00een Figura 7 anterioar\u0103, curentul de flac\u0103r\u0103 rezultat se modific\u0103 constant \u00een timpul fiec\u0103rui semiciclu de alimentare alternativ\u0103. \u00cen consecin\u021b\u0103, cantitatea de curent este aceea\u0219i \u00een fiecare direc\u021bie.<\/p>\n<p>Sistemul de rectificare a fl\u0103c\u0103rii utilizeaz\u0103, de asemenea, doi electrozi, dar cu o diferen\u021b\u0103 important\u0103: electrodul de \u00eemp\u0103m\u00e2ntare este mult mai mare dec\u00e2t electrodul de flac\u0103r\u0103. De obicei, electrodul de \u00eemp\u0103m\u00e2ntare va fi capul arz\u0103torului. \u00cen unele cazuri, trebuie ad\u0103ugate tije sau pl\u0103ci metalice suplimentare la arz\u0103tor pentru a m\u0103ri suprafa\u021ba de \u00eemp\u0103m\u00e2ntare, deoarece aceasta trebuie s\u0103 fie de cel pu\u021bin 4 ori mai mare (de obicei de p\u00e2n\u0103 la 10 ori mai mare) dec\u00e2t tija de flac\u0103r\u0103 sau electrodul de flac\u0103r\u0103. (Figura 8).<\/p>\n<figure id=\"attachment_28\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-28\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-163 size-full\" src=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Rectified-flame-rod-ground-area-e1643762136917.jpg\" sizes=\"auto, (max-width: 586px) 100vw, 586px\" srcset=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Rectified-flame-rod-ground-area-e1643762136917.jpg 586w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Rectified-flame-rod-ground-area-e1643762136917-300x190.jpg 300w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Rectified-flame-rod-ground-area-e1643762136917-65x41.jpg 65w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Rectified-flame-rod-ground-area-e1643762136917-225x142.jpg 225w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Rectified-flame-rod-ground-area-e1643762136917-350x222.jpg 350w\" alt=\"Dou\u0103 tipuri de arz\u0103toare pilot cu componente identificate\" width=\"586\" height=\"371\" \/><figcaption id=\"caption-attachment-28\" class=\"wp-caption-text\">Figura 8 Zona de \u00eemp\u0103m\u00e2ntare a tijei de flac\u0103r\u0103 rectificate<\/figcaption><\/figure>\n<p>Pentru un sistem redresat, atunci c\u00e2nd o tensiune de alimentare alternativ\u0103 este plasat\u0103 \u00eentre cei doi electrozi \u00een timpul primei jum\u0103t\u0103\u021bi a ciclului de curent alternativ, tija fl\u0103c\u0103rii este pozitiv\u0103, iar zona de \u00eemp\u0103m\u00e2ntare este negativ\u0103 (Figura 9 A). Ionii \u00eenc\u0103rca\u021bi pozitiv se colecteaz\u0103 pe zona de \u00eemp\u0103m\u00e2ntare \u00eenc\u0103rcat\u0103 negativ. Deoarece zona de \u00eemp\u0103m\u00e2ntare este foarte mare, aceasta con\u021bine mul\u021bi ioni. Ionii \u00eenc\u0103rca\u021bi pozitiv atrag un flux mare de electroni \u00een flac\u0103r\u0103, mai mult dec\u00e2t dac\u0103 zona de \u00eemp\u0103m\u00e2ntare ar avea aceea\u0219i dimensiune cu tija fl\u0103c\u0103rii. Acest lucru are ca rezultat un curent mare care curge de la zona de \u00eemp\u0103m\u00e2ntare la tija fl\u0103c\u0103rii \u00een timpul primei jum\u0103t\u0103\u021bi a ciclului de alimentare alternativ\u0103 (Figura 9 C).<\/p>\n<figure id=\"attachment_28\" class=\"wp-caption aligncenter\" aria-describedby=\"caption-attachment-28\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-164\" src=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Current-flow-in-a-flame-rectification-system-e1643762266489.jpg\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" srcset=\"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Current-flow-in-a-flame-rectification-system-e1643762266489.jpg 1369w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Current-flow-in-a-flame-rectification-system-e1643762266489-300x138.jpg 300w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Current-flow-in-a-flame-rectification-system-e1643762266489-1024x473.jpg 1024w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/1_Current-flow-in-a-flame-rectification-system-e1643762266489-768x355.jpg 768w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Current-flow-in-a-flame-rectification-system-e1643762266489-65x30.jpg 65w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Current-flow-in-a-flame-rectification-system-e1643762266489-225x104.jpg 225w, https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Current-flow-in-a-flame-rectification-system-e1643762266489-350x162.jpg 350w\" alt=\"9A: prima jum\u0103tate a cercului de curent alternativ. 9B: a doua jum\u0103tate a cercului de curent alternativ. 9C prezint\u0103 modific\u0103rile sarcinii ionului pe \u00eentregul ciclu.\" width=\"600\" height=\"277\" \/><figcaption id=\"caption-attachment-28\" class=\"wp-caption-text\">Figura 9 Curentul de curent \u00eentr-un sistem de rectificare a fl\u0103c\u0103rii<\/figcaption><\/figure>\n<p>\u00cen timpul celei de-a doua jum\u0103t\u0103\u021bi a ciclului, are loc procesul invers (Figura 9 B). Cu toate acestea, capacitatea tijei de flac\u0103r\u0103 de a re\u021bine ioni este mai mic\u0103 dec\u00e2t aria de \u00eemp\u0103m\u00e2ntare, iar curentul de flac\u0103r\u0103 rezultat este mai mic (Figura 9 C).<\/p>\n<p>Deoarece curentul \u00eentr-o direc\u021bie este mult mai mare dec\u00e2t curentul \u00een cealalt\u0103 direc\u021bie, curentul rezultat este, practic, un curent continuu pulsatoriu (Figura 9C). Semnalul fl\u0103c\u0103rii ar trebui s\u0103 fie constant atunci c\u00e2nd este m\u0103surat cu un microampermetru de curent continuu (\u03bcA).<\/p>\n<p>Avantajul unui sistem rectificat fa\u021b\u0103 de un sistem cu conductivitate este c\u0103 sistemul rectificat poate detecta o scurgere cu rezisten\u021b\u0103 mare. Uneori apare un scurtcircuit \u00eentre tija fl\u0103c\u0103rii \u0219i mas\u0103; carbonul se poate acumula \u00eentre tije sau ceramica izolatoare se poate fisura \u0219i permite umezelii s\u0103 ofere o cale c\u0103tre mas\u0103. Dac\u0103 se \u00eent\u00e2mpl\u0103 acest lucru, fluxul de curent este acela\u0219i \u00een ambele direc\u021bii, iar acest semnal ar fi respins de controlul de protec\u021bie a fl\u0103c\u0103rii ca o defec\u021biune a fl\u0103c\u0103rii.<\/p>\n<p>Source: <em><a href=\"https:\/\/opentextbc.ca\/plumbing3e\/chapter\/describe-flame-detectors\/\">Sarcina de \u00eenv\u0103\u021bare 2 \u2013 Blocul E: Sisteme de gaz combustibil<\/a><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Detectoarele de flac\u0103r\u0103 Sistemul de control al centrale pe gaz utilizeaz\u0103 dispozitive de detectare a fl\u0103c\u0103rii pentru a asigura aprinderea \u00een siguran\u021b\u0103 a fl\u0103c\u0103rii pilot \u0219i\/sau a arz\u0103torului principal. Cunoa\u0219terea modului \u00een care func\u021bioneaz\u0103 detectoarele de flac\u0103r\u0103, unde sunt aplicate \u0219i cum interac\u021bioneaz\u0103 cu alte controale este important\u0103 pentru \u00een\u021belegerea circuitului general de siguran\u021b\u0103 a &#8230; <a title=\"Sisteme de detectare a flacarii in Centralele termice pe gaz (modele mai vechi)\" class=\"read-more\" href=\"https:\/\/www.dioda.ro\/blog\/centrale-termice\/sisteme-de-detectare-a-flacarii-in-centralele-termice-pe-gaz-modele-mai-vechi\/\" aria-label=\"Read more about Sisteme de detectare a flacarii in Centralele termice pe gaz (modele mai vechi)\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":1557,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[76],"tags":[],"class_list":["post-1549","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-centrale-termice"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/www.dioda.ro\/blog\/wp-content\/uploads\/2025\/04\/Rectified-flame-rod-ground-area-e1643762136917.jpg","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p8WdYv-oZ","jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/posts\/1549","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/comments?post=1549"}],"version-history":[{"count":6,"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/posts\/1549\/revisions"}],"predecessor-version":[{"id":1599,"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/posts\/1549\/revisions\/1599"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/media\/1557"}],"wp:attachment":[{"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/media?parent=1549"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/categories?post=1549"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dioda.ro\/blog\/wp-json\/wp\/v2\/tags?post=1549"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}