Bukatun amfani da buƙatun rufewa na ƙananan bawul ɗin zafin jiki yadda za a zaɓi kayan ƙaramin bawul ɗin zafin jiki

Bukatun amfani da buƙatun rufewa na ƙananan bawul ɗin zafin jiki yadda za a zaɓi kayan ƙaramin bawul ɗin zafin jiki

2. Tasirin ƙananan zafin jiki akan aikin rufewa na bawul
2.1 nau'i-nau'i nau'i-nau'i masu rufewa marasa ƙarfe
Bawul ɗin ƙwallon ƙwallon ƙafa da bawul ɗin malam buɗe ido suna aiki a zazzabi gabaɗaya suna amfani da ƙarfe zuwa nau'ikan hatimin kayan da ba na ƙarfe ba. Saboda girman girman kayan da ba na ƙarfe ba, ƙayyadaddun matsa lamba da ake buƙata don rufewa yana da ƙananan, don haka rufewa yana da kyau. Duk da haka, a cikin ƙananan zafin jiki, saboda haɓakar haɓakar kayan da ba na ƙarfe ba ya fi girma fiye da na kayan ƙarfe, raguwar ƙananan zafin jiki da raguwa na hatimin ƙarfe, jikin bawul da sauran sassa sun bambanta sosai, wanda ke kaiwa ga raguwa mai tsanani na rufe takamaiman matsa lamba da sakamakon rufewa ba za a iya rufe shi ba. Yawancin kayan da ba na ƙarfe ba suna da ƙarfi kuma sun zama masu gatsewa a yanayin zafi na cryogenic, suna rasa ƙarfi, yana haifar da kwararar sanyi da annashuwa. Irin su roba a yanayin zafi da ke ƙasa da zafin gilashin sa, zai rasa ƙarfi gaba ɗaya, ya zama gilashi, ya rasa ƙarfinsa. Bugu da kari, ba za a iya amfani da roba ga LNG bawuloli saboda yana da kumfa fadada a cikin LNG matsakaici. Saboda haka, a halin yanzu a cikin zane na low zafin jiki bawul, da general zafin jiki ne m fiye da -70 ℃ daina amfani da wadanda ba karfe sealing karin kayan, ko wadanda ba karfe kayan ta musamman tsari a cikin karfe da kuma wadanda ba karfe hade tsarin irin.
Bisa ga bayanan kasashen waje, wasu kayan da ba na ƙarfe ba za a iya amfani da su da kyau a cikin yanayin cryogenic. A shekarun 1970, "Slings", sabon filastik daga Irish Suttukan Co., Ltd. Shin wani nau'in girman ƙarfin ƙwayoyin cuta mai girma a -269 ° C, ba su yi karya ba a ƙarƙashin wani mummunan damuwa, da kuma kiyaye babba juriya. Filastik ɗin Mylar da aka haɓaka a Faransa har yanzu yana da ƙarfi sosai a zazzabi na hydrogen ruwa (-253 ℃). An gwada mariƙin polycarbonate na HT Lomanenko na tsohuwar Tarayyar Soviet a cikin ruwa nitrogen (-196 ℃). Bayanan sun nuna cewa polycarbonate yana da tasiri mai kyau na rufewa a ƙananan zafin jiki.
2.2 Metal hatimi biyu
A ƙarƙashin yanayin ƙarancin zafin jiki, ƙarfin da taurin kayan ƙarfe yana ƙaruwa, filastik da tauri yana raguwa, yana nuna nau'ikan nau'ikan nau'ikan ƙananan yanayin sanyi mai sanyi, yana tasiri sosai ga aiki da amincin bawul. Domin ya hana low danniya gaggautsa karaya na kayan a low zafin jiki, a lokacin da zayyana low zafin jiki bawuloli, ferritic bakin karfe kayan da ake amfani da kullum lokacin da yawan zafin jiki ne mafi girma fiye da -100 ℃, yayin da lokacin da zazzabi ne kasa da -100 ℃, da bawul. jiki, bawul cover, bawul kara da sealing wurin zama mafi yawa amfani da fuska-tsakiyar cubic ragargaza austenitic bakin karfe, jan karfe da kuma jan karfe gami, aluminum da aluminum gami, da dai sauransu Amma saboda Tauri na aluminum da aluminum gami ba high, da abrasion juriya da abrasion juriya na sealing surface ne matalauta, don haka da wuya a yi amfani da a cikin low zafin jiki bawul. Gabaɗaya yi amfani da kayan bakin ƙarfe na austenitic, waɗanda aka saba amfani da su 0Cr18Ni9, 00Cr17Ni12Mo2(304, 316L), da dai sauransu, waɗannan kayan ba su da ƙarancin zafin jiki mai tsananin sanyi, ƙarƙashin yanayin ƙarancin zafin jiki, har yanzu na iya kiyaye babban tauri.
Duk da haka, austenitic bakin karfe a matsayin low zafin jiki bawul karfe hatimi karin abu ma yana da wasu shortcomings. Saboda yawancin waɗannan kayan suna cikin yanayin haɓakawa a yanayin zafin jiki, austenite a cikin kayan yana canzawa zuwa martensite lokacin da aka saukar da zafin jiki a ƙasan yanayin canjin lokaci (MS). Domin jiki a tsakiya cubic lattice na martensite yawa ne m fiye da na fuska-tsakiyar cubic lattice na austenite, kuma saboda wasu carbon atoms shirya jiki a tsakiya cubic lattice matsayi tsari, yin lattice tare da C axis girma, don haka karuwa da girma canje-canje. lalacewa ta hanyar ciki danniya, yin asali bayan nika saduwa da sealing bukatun na sealing surface buckling nakasawa, sakamakon hatimi gazawar.
Bugu da ƙari ga gazawar nakasawa na saman rufewa wanda ke haifar da canjin yanayin ƙarancin zafin jiki, saboda bambancin zafin jiki na kowane bangare ko bambancin kaddarorin jiki tsakanin kayan daban-daban, wanda ke haifar da raguwar rashin daidaituwa, damuwa bambancin yanayin zafi shima zai faru. Lokacin da danniya ya kasance ƙasa da ƙayyadaddun ƙayyadaddun kayan aiki, ana haifar da ɓarna mai jujjuyawa a cikin farfajiyar rufewa. Lokacin da yanayin zafi na wani sashi ya wuce iyakar yawan amfanin ƙasa na kayan, sassan za su sami murdiya da nakasar da ba za a iya jurewa ba, wanda kuma zai haifar da gazawar wurin rufewa kuma ya shafi tasirin rufewa.
Dangane da tasirin ƙarancin zafin jiki akan nau'in hatimi na ƙarfe, dole ne a ɗauki matakan da suka dace don sanya nakasar shingen karfen ƙarami ko kuma nakasar wurin rufewa yana da ɗan tasiri akan aikin hatimi. Da fari dai, dangane da kayan, ya kamata mu yi ƙoƙarin zaɓar kayan da babban kwanciyar hankali na tsarin metallographic (kamar 316L amma tare da farashi mai girma). Abu na biyu, don jiki, murfin, kara, hatimi da sauran kayan austenitic da aka yi da sassa dole ne a sarrafa su a cikin ƙananan zafin jiki, don haka ana aiwatar da canjin martensite da nakasar kayan kafin a gama. Yanayin zafin jiki na ƙananan zafin jiki ya kamata ya zama ƙasa da yanayin canjin yanayi (MS) kuma ƙasa da ainihin zafin jiki na bawul, kuma lokacin magani ya kamata ya zama 2 ~ 4h. Idan ya cancanta, ana iya aiwatar da maganin ƙarancin zafin jiki da yawa ko maganin tsufa da ya dace. Bugu da ƙari ga matakan da ke sama, ƙirar tsarin ya kamata kuma a yi la'akari da shi don rage tasirin rufewar nakasa a kan aikin rufewa, kamar a cikin ƙirar ƙofofi, bawul ɗin ball da bawul ɗin malam buɗe ido na iya yin la'akari da yin amfani da tsarin rufewa na roba, don haka cewa ƙananan nakasar zafin jiki za'a iya ramawa kaɗan. Domin globe bawul ya zama conical hatimi tsarin, sabõda haka, low zazzabi nakasawa a kan sealing surface na kananan tasiri.
3. Tasirin ƙananan zafin jiki akan aikin rufewa na bawul
3.1 Tushen shiryawa
Saboda lahani na roba abu a low zafin jiki da sanyi gaggautsa da tsanani sanyi kwarara sabon abu na mafi wadanda ba karfe kayan, da sealing zane tsakanin kara da bawul jiki na low zazzabi bawul ba zai iya amfani da nau'i na sealing zobe, iya. kawai yi amfani da tsarin hatimin akwatin marufi da tsarin hatimin bellow. Ana amfani da hatimin janareta a cikin matsakaici baya ƙyale ɗigogi kuma bai dace da ɗaukar kaya ba, rayuwar tsarin sa guda ɗaya gajere ne, farashin tsarin multilayer yana da yawa, sarrafawa yana da wahala, don haka gabaɗaya ba amfani.
Tsarin rufe akwatin shaƙewa yana da sauƙin ƙira da sarrafawa, mai sauƙin kulawa da maye gurbinsa, kuma yana da yawa a aikace-aikace mai amfani. Duk da haka, yawan zafin jiki na aiki na marufi ba zai iya zama ƙasa da -40 ℃. Don tabbatar da aikin hatimi na marufi, akwatin akwatin na'urar bututun mai ƙarancin zafin jiki ya kamata a yi aiki a ƙarƙashin yanayin kusa da yanayin zafi. A ƙananan zafin jiki, tare da rage yawan zafin jiki, elasticity na filler a hankali yana ɓacewa, kuma aikin da ba a yi ba ya ragu. Saboda yayyan kafofin watsa labarai lalacewa ta hanyar shiryawa da bawul tushe kankara, zai shafi al'ada aiki na bawul tushe, amma kuma saboda motsi na bawul tushe zai zama packing karce, haifar da tsanani yayyo. Saboda haka, a karkashin al'ada yanayi, da low zafin jiki shiryawa da ake bukata don aiki a zazzabi sama da 0 ℃, wanda bukatar da zane na dogon wuyan wuyansa bawul cover tsarin, sabõda haka, shiryawa akwatin daga low zazzabi matsakaici, da kuma zabi na shiryawa. tare da ƙananan halayen zafin jiki. Abubuwan da aka fi amfani da su sune polytetrafluoroethylene, asbestos, igiya polytetrafluoroethylene asbestos igiya da graphite mai sassauƙa, waɗanda, saboda asbestos ba zai iya guje wa ƙyalli ba, polytetrafluoroethylene madaidaiciyar haɓaka haɓaka yana da girma sosai, yanayin kwararar sanyi yana da mahimmanci, don haka gabaɗaya ba a amfani dashi. M graphite ne mai kyau sealing abu, gas, ruwa ne impermeable, matsa lamba ne mafi girma fiye da 40%, resilience ne mafi girma fiye da 15%, danniya shakatawa ne kasa da 5%, da ƙananan fastening matsa lamba za a iya shãfe haske. Hakanan yana da lubricity na kansa, wanda aka yi amfani da shi azaman bawul shiryawa na iya hana shiryawa yadda yakamata da bawul ɗin lalacewa, aikin hatimin sa a fili ya fi kayan asbestos na gargajiya, don haka yana ɗaya daga cikin mafi kyawun kayan rufewa.
Saboda filler gabaɗaya abu ne wanda ba ƙarfe ba ne, ƙimar faɗaɗawar layi ta fi girma fiye da akwatin filler ɗin ƙarfe da bututun bawul. Sabili da haka, lokacin da tattarawar da aka taru a zafin jiki ya faɗi zuwa wani yanayin zafi, raguwarta ya fi na ramin tattarawa da bututun bawul, wanda zai iya haifar da ɗigowa saboda raguwar matsa lamba. A cikin ƙira, za a iya shigar da ƙugiya mai ɗaukar hoto tare da ƙungiyoyi masu yawa na gaskets na faifan diski, ta yadda za a iya ci gaba da ɗora ƙarfin ƙaddamar da marufi a ƙananan zafin jiki don tabbatar da tasirin rufewa.
Ƙananan leakage haɗe da marufi da Kamfanin Garlock ya samar a Amurka, ƙarshen zoben an yi shi da tushen fiber fiber braided diski, zoben rufewa an yi shi da babban nau'in lu'u-lu'u mai zane mai zane, ta hanyar ƙoƙon da tsarin mazugi da haɓaka radial. halaye, don haka an inganta aikin rufewa.
Ƙananan nakasar ƙanƙara na kayan kara zai kuma shafi aikin rufewa na marufi. Sabili da haka, daidai da jikin bawul, murfin bawul, rufe kayan kayan haɗi, mai tushe kuma dole ne ya zama aikin cryogenic bayan kammalawa, don yin ƙarancin ƙarancin zafin jiki yana ƙarami. Bugu da ƙari, saboda bakin karfe na austenitic da aka yi amfani da shi a cikin kayan aikin cryogenic ba za a iya yin amfani da zafi don inganta taurin saman ba, haɗin gwiwa tsakanin kara da marufi zai iya lalata juna, yana haifar da zubar da ciki a cikin marufi. Sabili da haka, dole ne a yi amfani da tushe mai tushe tare da chromium mai wuya ko nitride don inganta taurin saman.
3.2 Tsakiyar flange gasket
Duka hatimin flange na tsakiya na bawul da haɗin waje na bawul ɗin haɗin flange gabaɗaya a cikin nau'ikan gaskets ne. Tun da gasket abu zai taurare da rage plasticity a low zafin jiki, da gasket ga low zafin jiki bawuloli yana da mafi girma bukatun. Dole ne ya sami abin dogara da hatimi da farfadowa a yanayin zafi na al'ada, ƙananan zafin jiki da canjin zafin jiki. Ya kamata a yi la'akari da tasirin ƙarancin zafin jiki akan aikin rufewa na gasket gabaɗaya.
Dangane da nau'ikan rufewar gasket da aka saba amfani da su, tsayin kulle, gasket da kaurin flange zai ragu yayin da zafin jiki ya ragu. Domin tabbatar da abin dogara ga gasket sealing a low zazzabi, shi dole ne a hadu
Δ HT3 Δ HT - Δ HT1 - Δ H1 Buga a cikin
ΔH1 - Ƙunƙarar ƙaƙƙarfan ƙaƙƙarfan taro, mm
Δ H1 = 1 / E1H sigma
ΔHT1 - Bolt raguwa a cikin kewayon zafin jiki na ΔT, mm
ΔHT1 Δ T = H alpha 1
ΔHT - raguwar gasket a cikin yankin zafin jiki na ΔT, mm
Δ HT = alpha 2 Δ h T
ΔHT3 - Rage ƙananan flanges na sama da ƙananan a cikin yankin zafin jiki na ΔT, mm
Δ HT3 = alpha 3 Δ T1 (H-H)
σ1 - Ƙaddamarwa na Bolt, N/mm
E1 - Modules na roba, N/mm
α1, α2, α3 - su ne madaidaiciyar haɓaka haɓakar faɗaɗawa na aron ƙarfe, gasket da kayan flange, bi da bi, mm/m
H, H - mm
Lokacin da hatimin gasket ya kai ƙananan zafin jiki da aka ƙera daga ɗakin zafin jiki, jimlar raguwar manyan flanges na sama da na ƙasa da raguwar gasket ɗin dole ne ya zama ƙasa da jimillar raguwar kusoshi da nakasar ƙwanƙwasa na aron. taro, don tabbatar da cewa gasket har yanzu yana da wani ɓangare na preload a aiki zafin jiki da kuma kula da sealing ikon.
Saboda haka, ya kamata a yi la'akari da abubuwa hudu a cikin zane. ① An yi ƙugiya da kayan aiki tare da mafi girman haɓakar haɓakar haɓakar layin layi, wanda ke da raguwa mafi girma a ƙananan zafin jiki. ② An yi flange da kayan aiki tare da ƙaramar haɓakar haɓakar layin layi don rage ΔHT3. ③ Rage kauri na gasket, kuma amfani da kayan tare da ƙananan haɓakar faɗaɗa madaidaiciya azaman gasket. (4) Ƙara nakasar ƙwanƙwasa na kusoshi.
Don ƙananan bawul ɗin zafin jiki a ƙasa -100 ℃, kayan jiki da kayan kwalliya galibi ana yin su ne da bakin karfe na austenitic, ƙimar faɗaɗa madaidaiciya iri ɗaya ce, don haka yana da mahimmanci don zaɓar kayan gasket ɗin da suka dace kuma ƙara haɓakar nakasar kusoshi. Ideal low zafin jiki gasket abu, a dakin zafin jiki taurin ne low, a low zazzabi resilience iya zama mai kyau, mikakke fadada coefficient ne karami kuma yana da wani inji ƙarfi. A aikace aikace, winding gaskets sanya da bakin karfe tef cike da asbestos ko polytetrafluorethylene ko m graphite gaba ɗaya amfani, da sealing sakamako na winding gaskets sanya na m graphite da bakin karfe ne manufa. Amma ga ƙãra tensile nakasawa na amosanin gabbai, saboda da iyaka na aron kusa shigarwa preload, da ƙarar gefe ba yawa, don haka shi za a iya la'akari da saita diski spring gasket zuwa rama.