{"id":2159,"date":"2021-07-14T07:35:14","date_gmt":"2021-07-14T07:35:14","guid":{"rendered":"https:\/\/wldstainless.com\/?p=2159"},"modified":"2021-07-14T07:38:30","modified_gmt":"2021-07-14T07:38:30","slug":"the-choice-of-stainless-steel-material-for-food-and-beverage-industrial","status":"publish","type":"post","link":"https:\/\/wldstainless.com\/cs\/the-choice-of-stainless-steel-material-for-food-and-beverage-industrial\/","title":{"rendered":"V\u00fdb\u011br materi\u00e1lu z nerezov\u00e9 oceli pro potravin\u00e1\u0159sk\u00fd a n\u00e1pojov\u00fd pr\u016fmysl"},"content":{"rendered":"<p>V\u011bt\u0161ina probl\u00e9m\u016f, kter\u00fdm \u010del\u00ed pou\u017eit\u00ed nerezov\u00e9 oceli v ml\u00e9k\u00e1rensk\u00e9m a jin\u00e9m potravin\u00e1\u0159sk\u00e9m pr\u016fmyslu, souvis\u00ed s v\u00fdm\u011bn\u00edky tepla a p\u0159\u00edrodn\u00ed povrchovou vodou, jako je studni\u010dn\u00ed voda. Stejn\u011b jako pivovary, v\u011bt\u0161ina potravin\u00e1\u0159sk\u00fdch odv\u011btv\u00ed \u010dasto pou\u017e\u00edv\u00e1 hork\u00e1 m\u00e9dia, kter\u00e1 jsou oh\u0159\u00edv\u00e1na p\u00e1rou nebo chlazena vodou, co\u017e je spojeno s pasterizac\u00ed a sterilizac\u00ed, a proto se \u010dasto pot\u00fdkaj\u00ed s probl\u00e9my, jako jsou praskliny zp\u016fsoben\u00e9 koroz\u00ed pod nap\u011bt\u00edm. Obecn\u011b p\u0159i zpracov\u00e1n\u00ed potravin nedoch\u00e1z\u00ed ke korozi standardn\u00ed nerezov\u00e9 oceli jako nap\u0159 <a href=\"https:\/\/wldstainless.com\/materials\/austenitic-stainless-steel\/304-304l-stainless-steel\/\">AISI304<\/a> nebo 316. \u0160irok\u00e1 \u0161k\u00e1la zpracovatelsk\u00fdch metod v tomto odv\u011btv\u00ed v\u0161ak vede k mnoha r\u016fzn\u00fdm korozn\u00edm poruch\u00e1m. Jako:<\/p>\n<ul>\n<li>Eroze\/koroze ve v\u00fdm\u011bn\u00edc\u00edch tepla z nerezov\u00e9 oceli.<\/li>\n<li>Rovnom\u011brn\u00e1 koroze zp\u016fsoben\u00e1 kyselinou ml\u00e9\u010dnou a jin\u00fdmi organick\u00fdmi kyselinami p\u0159i vysok\u00e9 teplot\u011b.<\/li>\n<li>Mikrobi\u00e1ln\u00ed koroze zp\u016fsoben\u00e1 povrchovou vodou nebo studni\u010dn\u00ed vodou.<\/li>\n<li>Nap\u011b\u0165ov\u00e9 korozn\u00ed praskliny, hlavn\u011b \u201echloridov\u00e9 trhliny\u201c.<\/li>\n<li>Korozn\u00ed \u00fanava zp\u016fsoben\u00e1 vibracemi.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>U deskov\u00fdch v\u00fdm\u011bn\u00edk\u016f tepla v ml\u00e9k\u00e1rensk\u00e9m pr\u016fmyslu se syrov\u00e1tka, ml\u00e9ko a procesn\u00ed voda zpracov\u00e1vaj\u00ed prost\u0159ednictv\u00edm deskov\u00fdch v\u00fdm\u011bn\u00edk\u016f tepla vyroben\u00fdch z nerezov\u00e9 oceli 1.4401, jak je uvedeno v tabulce n\u00ed\u017ee.<\/p>\n<table>\n<tbody>\n<tr>\n<td width=\"213\">produkty<\/td>\n<td width=\"213\">Vstupn\u00ed teplota, \u2103<\/td>\n<td width=\"213\">\u00a0V\u00fdstupn\u00ed teplota, \u2103<\/td>\n<td width=\"213\">Tlak<\/td>\n<\/tr>\n<tr>\n<td width=\"213\">Syrov\u00e1tka<\/td>\n<td width=\"213\">30<\/td>\n<td width=\"213\">10<\/td>\n<td width=\"213\">St\u0159edn\u00ed<\/td>\n<\/tr>\n<tr>\n<td width=\"213\">Ml\u00e9ko<\/td>\n<td width=\"213\">7<\/td>\n<td width=\"213\">30<\/td>\n<td width=\"213\">Vysok\u00fd<\/td>\n<\/tr>\n<tr>\n<td width=\"213\">Procesn\u00ed voda<\/td>\n<td width=\"213\">57<\/td>\n<td width=\"213\">14<\/td>\n<td width=\"213\">N\u00edzk\u00fd<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<p>Aby se zabr\u00e1nilo \u00faniku kontaminovan\u00fdch potravin, je tlak procesn\u00ed vody udr\u017eov\u00e1n na co nejni\u017e\u0161\u00ed \u00farovni. K net\u011bsnosti doch\u00e1z\u00ed p\u0159i vz\u00e1jemn\u00e9 kolizi tenk\u00fdch desek v m\u00edst\u011b tlaku, co\u017e je zp\u016fsobeno \u00fanavov\u00fdmi trhlinami v tenk\u00e9m pr\u016f\u0159ezu po erozi a korozi tlakov\u00e9ho bodu. Metalografick\u00e9 mikroskopick\u00e9 studium \u0159ezu ukazuje, \u017ee nedo\u0161lo k \u017e\u00e1dn\u00e9 korozn\u00ed trhlin\u011b pod nap\u011bt\u00edm. Vzhledem k tomu, \u017ee n\u00edzk\u00fd tlak je na stran\u011b procesn\u00ed vody, spojen\u00fd s kol\u00eds\u00e1n\u00edm tlaku a vibracemi proud\u011bn\u00ed tekutiny, doch\u00e1z\u00ed na t\u00e9to stran\u011b k erozi\/korozi. Zp\u016fsob, jak zabr\u00e1nit fyzick\u00e9 kolizi desek, je zm\u011bnit tlak a kol\u00eds\u00e1n\u00ed tlaku nebo zv\u011bt\u0161it rozestupy mezi deskami.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Mikrobi\u00e1ln\u00ed koroze zp\u016fsoben\u00e1 studni\u010dn\u00ed vodou<\/strong><\/p>\n<p><img decoding=\"async\" class=\"size-full wp-image-2162 alignleft\" src=\"https:\/\/wldstainless.com\/wp-content\/uploads\/2021\/07\/Microbial-corrosion-caused-by-well-water.png\" alt=\"\" width=\"366\" height=\"454\" srcset=\"https:\/\/wldstainless.com\/wp-content\/uploads\/2021\/07\/Microbial-corrosion-caused-by-well-water.png 366w, https:\/\/wldstainless.com\/wp-content\/uploads\/2021\/07\/Microbial-corrosion-caused-by-well-water-242x300.png 242w\" sizes=\"(max-width: 366px) 100vw, 366px\" \/>Potravin\u00e1\u0159sk\u00fd pr\u016fmysl obvykle vyu\u017e\u00edv\u00e1 studni\u010dn\u00ed vodu. Obsah \u017eeleza ve studni\u010dn\u00ed vod\u011b je pom\u011brn\u011b vysok\u00fd, co\u017e m\u016f\u017ee aktivovat bakterie p\u0159\u00edbuzn\u00e9 \u017eelezu a zp\u016fsobit silnou korozi. Jednou z b\u011b\u017en\u011b pou\u017e\u00edvan\u00fdch metod \u00fapravy vody je odstran\u011bn\u00ed \u017eeleza ze studni\u010dn\u00ed vody, aby j\u00eddlo l\u00e9pe chutnalo a aby se zabr\u00e1nilo korozi obal\u016f a zpracovatelsk\u00fdch za\u0159\u00edzen\u00ed po \u010di\u0161t\u011bn\u00ed a oplachov\u00e1n\u00ed. Povrchov\u00e1 a studni\u010dn\u00ed voda tak\u00e9 obsahuje \u0159adu typ\u016f mikroorganism\u016f, kter\u00e9 jsou aktivn\u00ed v aerobn\u00edch i anaerobn\u00edch podm\u00ednk\u00e1ch. Aerobn\u00ed bakterie p\u0159\u00edbuzn\u00e9 \u017eelezu oxiduj\u00ed ionty \u017eeleza, zat\u00edmco anaerobn\u00ed bakterie p\u0159\u00edbuzn\u00e9 \u017eelezu ionty \u017eeleza redukuj\u00ed. Tyto dv\u011b reakce jsou nakonec klasifikov\u00e1ny jako mikrobi\u00e1ln\u00ed koroze (MIC). Jin\u00e9 mikroorganismy mohou b\u00fdt tak\u00e9 aktivn\u00ed ve vod\u011b, jako jsou bakterie redukuj\u00edc\u00ed kyselinu s\u00edrovou, bakterie produkuj\u00edc\u00ed kyselinu. Ve stejn\u00e9m biofilmu mohou b\u00fdt aktivn\u00ed aerobn\u00ed bakterie a (n\u00ed\u017ee) anaerobn\u00ed bakterie.<\/p>\n<p>P\u0159i pou\u017eit\u00ed studni\u010dn\u00ed vody k o\u0161et\u0159en\u00ed konzervovan\u00e9 zeleniny (po pasterizaci propl\u00e1chnout a vychladit). Tam, kde voda nete\u010de del\u0161\u00ed dobu, 316L vyroben\u00e9 trubky prote\u010dou do \u0161esti m\u011bs\u00edc\u016f kv\u016fli vysok\u00e9 teplot\u011b vody. Samotn\u00e1 studni\u010dn\u00ed voda je studen\u00e1 (pod 10 \u00b0C), ale v l\u00e9t\u011b m\u016f\u017ee snadno stoupnout na 30 \u00b0C, pokud z\u016fstane v potrub\u00ed po dlouhou dobu st\u00e1t. Ve srovn\u00e1n\u00ed s Legionellou se korozn\u00ed biofilmy tvo\u0159ily p\u0159i vy\u0161\u0161\u00edch rychlostech aktivity p\u0159i vy\u0161\u0161\u00edch teplot\u00e1ch.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>D\u016flkov\u00e1 koroze zp\u016fsoben\u00e1 dezinfekc\u00ed a sterilizac\u00ed chl\u00f3rem<\/strong><\/p>\n<p>Chlornan sodn\u00fd se b\u011b\u017en\u011b pou\u017e\u00edv\u00e1 p\u0159i \u010di\u0161t\u011bn\u00ed a dezinfekci za\u0159\u00edzen\u00ed z nerezov\u00e9 oceli. Pokud je koncentrace chlornanu sodn\u00e9ho p\u0159\u00edli\u0161 vysok\u00e1 nebo doba \u010di\u0161t\u011bn\u00ed a dezinfekce je p\u0159\u00edli\u0161 dlouh\u00e1, chlornan sodn\u00fd zp\u016fsob\u00ed v\u00e1\u017enou korozi nerezov\u00e9 oceli, zvl\u00e1\u0161t\u011b kdy\u017e je teplota vy\u0161\u0161\u00ed ne\u017e 25 \u00b0C.<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Nap\u011b\u0165ov\u00fd korozn\u00ed lom<\/strong><\/p>\n<p>Existuje riziko chloridov\u00e9ho korozn\u00edho lomu p\u0159i teplot\u00e1ch nad 60 \u00b0C. S rostouc\u00ed deformac\u00ed za studena, tahov\u00fdm nap\u011bt\u00edm a obsahem chlorid\u016f se riziko zvy\u0161uje. V porovn\u00e1n\u00ed s trubkou deformovanou za studena bez \u017e\u00edh\u00e1n\u00ed je \u017e\u00edhan\u00e1 trubka necitliv\u00e1 na chloridov\u00e9 korozn\u00ed lomy. Vn\u011bj\u0161\u00ed strana ocelov\u00fdch trubek s p\u0159\u00edm\u00fdm svarem pou\u017e\u00edvan\u00fdch v ml\u00e9k\u00e1rensk\u00e9m pr\u016fmyslu je mnohem citliv\u011bj\u0161\u00ed na chloridy v d\u016fsledku tahov\u00e9ho nap\u011bt\u00ed v pr\u016f\u0159ezu zp\u016fsoben\u00e9ho ohybem b\u011bhem v\u00fdrobn\u00edho procesu. V jin\u00fdch aplikac\u00edch mohou b\u00fdt trubkov\u00e9 v\u00fdm\u011bn\u00edky tepla zodpov\u011bdn\u00e9 za chloridov\u00e9 korozn\u00ed prask\u00e1n\u00ed. Chloridov\u00e9 trhliny pod nap\u011bt\u00edm se pravd\u011bpodobn\u011bji vyvinou na jedn\u00e9 stran\u011b pl\u00e1\u0161t\u011b, pokud teplota p\u0159ekro\u010d\u00ed 60 \u00b0C. AISI 304 a 316 jsou na tento probl\u00e9m citliv\u00e9 a p\u0159i pou\u017eit\u00ed v cukern\u00fdch odpark\u00e1ch, kde mohou b\u00fdt feritick\u00e9 nerezov\u00e9 oceli, existuje riziko korozn\u00edho lomu pod nap\u011bt\u00edm. m\u00edsto toho pou\u017e\u00edt. Feritick\u00e1 nerezov\u00e1 ocel AISI 441 je \u0161iroce pou\u017e\u00edv\u00e1na v cukrovarnick\u00e9m pr\u016fmyslu, zejm\u00e9na AISI 439. V praktick\u00e9m pou\u017eit\u00ed je v\u00fdb\u011br potrub\u00ed vyvinut z nerezov\u00e9 oceli 304 a nerezov\u00e9 oceli 439. <a href=\"https:\/\/wldstainless.com\/materials\/austenitic-stainless-steel\/304-304l-stainless-steel\/\">304 nerezov\u00e1 ocel<\/a> pro krat\u0161\u00ed trubky a 439 pro del\u0161\u00ed trubky.<\/p>\n<p>Nerezov\u00e1 ocel 304: Ocel lze vybrat, pokud je d\u00e9lka trubky men\u0161\u00ed ne\u017e 3 metry. Koeficient tepeln\u00e9 rozta\u017enosti <a href=\"https:\/\/wldstainless.com\/materials\/austenitic-stainless-steel\/304-304l-stainless-steel\/\">304<\/a> nerezov\u00e1 ocel je 1,8 \u00d7 10-2 mm\/m\u2103, co\u017e je mnohem v\u011bt\u0161\u00ed ne\u017e u uhl\u00edkov\u00e9 oceli. Kdy\u017e m\u00e1 n\u00e1doba vysokou teplotu, tepeln\u00e9 nam\u00e1h\u00e1n\u00ed trubky je vysok\u00e9. Trubky z nerezov\u00e9 oceli AISI 304 byly \u017e\u00edh\u00e1ny po p\u0159\u00edm\u00e9m \u0161vov\u00e9m sva\u0159ov\u00e1n\u00ed v tov\u00e1rn\u011b.<\/p>\n<p>439 Nerezov\u00e1 ocel: ASTM439 je titanem stabilizovan\u00e1 feritick\u00e1 nerezov\u00e1 ocel (17% ~ 19%Cr) pou\u017e\u00edvan\u00e1 pro v\u00fdparn\u00edky nebo spir\u00e1ly a\u017e do d\u00e9lky 5 m. Riziko korozn\u00edho lomu pod nap\u011bt\u00edm je v\u011bt\u0161\u00ed, kdy\u017e je d\u00e9lka trubky v\u011bt\u0161\u00ed ne\u017e 7 m, koncentrace chlorid\u016f je vysok\u00e1 a stupe\u0148 deformace za studena je vysok\u00fd. U feritick\u00fdch korozivzdorn\u00fdch ocel\u00ed, jako je AISI 439, nedoch\u00e1z\u00ed k \u017e\u00e1dn\u00e9mu korozn\u00edmu lomu pod nap\u011bt\u00edm. Aby se zabr\u00e1nilo \u0161t\u011brbinov\u00e9 korozi, pokud to odolnost proti korozi a hygienick\u00e9 podm\u00ednky dovol\u00ed, lid\u00e9 obvykle pou\u017e\u00edvaj\u00ed v\u00fdm\u011bn\u00edk tepla s pl\u00e1\u0161t\u011bm z tlust\u00e9 uhl\u00edkov\u00e9 oceli a vnit\u0159n\u00ed st\u011bnou je tenk\u00e1 tlou\u0161\u0165ka Ocelov\u00e1 trubka AISI439. T\u00edmto zp\u016fsobem m\u016f\u017ee uhl\u00edkov\u00e1 ocel poskytnout katodickou ochranu tenkost\u011bnn\u00e9 trubky z nerezov\u00e9 oceli a m\u016f\u017ee sn\u00ed\u017eit konstruk\u010dn\u00ed a v\u00fdrobn\u00ed n\u00e1klady a prodlou\u017eit \u017eivotnost.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>","protected":false},"excerpt":{"rendered":"<p>V\u011bt\u0161ina probl\u00e9m\u016f, kter\u00fdm \u010del\u00ed pou\u017eit\u00ed nerezov\u00e9 oceli v ml\u00e9k\u00e1rensk\u00e9m a jin\u00e9m potravin\u00e1\u0159sk\u00e9m pr\u016fmyslu, souvis\u00ed s v\u00fdm\u011bn\u00edky tepla a p\u0159\u00edrodn\u00ed povrchovou vodou, jako je studni\u010dn\u00ed voda. Stejn\u011b jako pivovary i v\u011bt\u0161ina potravin\u00e1\u0159sk\u00fdch odv\u011btv\u00ed \u010dasto pou\u017e\u00edv\u00e1 hork\u00e1 m\u00e9dia, kter\u00e1 jsou oh\u0159\u00edv\u00e1na p\u00e1rou nebo chlazena vodou, co\u017e je spojeno s pasterizac\u00ed a sterilizac\u00ed, [\u2026]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[],"class_list":["post-2159","post","type-post","status-publish","format-standard","hentry","category-news"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/posts\/2159","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/comments?post=2159"}],"version-history":[{"count":3,"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/posts\/2159\/revisions"}],"predecessor-version":[{"id":2163,"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/posts\/2159\/revisions\/2163"}],"wp:attachment":[{"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/media?parent=2159"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/categories?post=2159"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wldstainless.com\/cs\/wp-json\/wp\/v2\/tags?post=2159"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}