Sealing cov ntaub ntawv ua lub luag haujlwm tseem ceeb hauv cryogenic trunnion pob li qub, uas tuaj yeem tiv thaiv kev tawm ntawm cov xov xwm thiab ua kom muaj kev nyab xeeb ntawm lub valve. Lawv qhov kev ua tau zoo cuam tshuam ncaj qha rau kev sib khi kev ntseeg siab, kev pab cuam lub neej thiab kev ua haujlwm ruaj khov ntawm lub valve hauv ultra- qhov kub thiab txias ib puag ncig. Lawv lub luag haujlwm tseem ceeb thiab kev xaiv cov hauv paus ntsiab lus tseem ceeb hauv qab no:
I. Lub luag haujlwm tseem ceeb ua haujlwm ntawm Sealing Materials
Cryogenic Sealing: Thaum kub ntawm -196℃(piv txwv li, kua nitrogen) los yog qis dua, cov khoom sib khi yuav tsum nyob twj ywm elastic thiab hloov tau los tiv thaiv kom tsis txhob muaj dej ntau vim qhov ua kom lub sealing nto voids vim hardening lossis shrinkage ntawm cov khoom. Cov roj hmab zoo tib yam, piv txwv li, tuaj yeem ua nkig ntawm qhov kub thiab txias, thaum cov ntaub ntawv tshwj xeeb cryogenic sealing (xws li, hloov kho PTFE (PTFE)) tseem tuaj yeem tuav lub siab sealing.
Media Corrosion kuj: Cryogenic media (piv txwv li, liquefied natural gas, kua oxygen) tej zaum yuav corrosive heev los yog chemically reactive. Cov ntaub ntawv sealing yuav tsum muaj tshuaj ruaj khov los tiv thaiv cov tshuaj tiv thaiv nrog qhov nruab nrab uas ua rau lub foob tsis ua haujlwm. Piv txwv li, hauv kev siv cov pa oxygen ua kua, cov ntaub ntawv uas muaj roj los yog cov tshuaj oxidizing yooj yim yuav tsum raug zam kom tsis txhob muaj kev phom sij.
Abrasion thiab corrosion kuj: Thaum lub valve qhib thiab kaw, kev sib txhuam ntawm lub puab thiab lub sealing npog tuaj yeem ua rau hnav thiab tsim kua muag, tshwj xeeb tshaj yog nyob rau hauv lub siab sib txawv, qhov yaig ntawm cov xov xwm tuaj yeem ua rau muaj kev puas tsuaj rau lub sealing nto. Sealing cov ntaub ntawv yuav tsum muaj siab hardness thiab nws tus kheej -lubrication los txo qhov hnav thiab ua rau lub neej ntev.
Thermal Expansion and Contraction Compensation: Thaum qhov kub thiab txias, lub valve lub cev hlau yuav shrinks ntau tshaj li cov khoom sealing, uas tej zaum yuav ua rau tsis sib npaug ntawm lub sealing nto. Cov khoom siv sealing yuav tsum tau them nyiaj rau qhov sib txawv ntawm qhov shrinkage los ntawm elastic deformation kom muaj kev sib cuag ntawm lub foob.
Adhesion tsis kam: Tom qab lub sijhawm ntev ntawm kev tsis ua haujlwm, lub sealing nto yuav nyuaj rau qhib thiab kaw vim crystallization lossis adhesion ntawm nruab nrab. Cov khoom siv sib khi yuav tsum muaj lub zog qis qis los tiv thaiv kev tshaj tawm adhesion thiab ua kom lub zog hloov pauv ntawm lub valve.
II. Txoj Cai Xaiv Sealant
1. Kub Adaptability
Cryogenic txwv: Xaiv cov khoom raws li qhov ntsuas kub tsawg kawg nkaus kom ntseeg tau tias nws cov iav hloov pauv kub (Tg) qis dua ua haujlwm kub.
Piv txwv li: PTFE (PTFE): Siv tau qhov kub thiab txias poob rau -200 degree, tab sis yuav tsum tau txhim kho kom txhim kho kev puas tsuaj.
PI (polyimide): Haum rau -269℃(ze xoom xoom) tab sis kim.
Saj zawg zog Graphite: Muaj feem xyuam rau qhov kub ntawm -200 degree, tab sis yuav tsum tsis txhob sib cuag nrog cov xov xwm oxidizing muaj zog.
2. Media Compatibility
Chemical Properties: Corrosion resistant cov ntaub ntawv raug xaiv raws li hom xov xwm (xws li hydrocarbons, kua oxygen, kua nitrogen). Piv txwv li, kev siv roj- cov khoom siv hauv cov ntawv thov oxygen yog txwv; PTFE lossis hlau ntsaws ruaj ruaj (xws li stainless hlau + saj zawg zog graphite) nyiam dua.
Rau cov xov xwm me me, cov khoom siv tsis zoo (piv txwv li, silicon carbide reinforced PTFE) yuav tsum.
3.Mechanical Properties
Compression rebound rate: Cov khoom yuav tsum tau deformed sai sai tom qab compression los them rau kev so thaum lub sij hawm ntev - siv. Saj zawg zog graphite, piv txwv li, muaj compression rebound ntawm tshaj 40%.
Cov tawv nqaij thiab lub zog: Siab- cov ntawv thov siab yuav tsum muaj siab- cov ntaub ntawv hardness (xws li, cemented carbide), tab sis kev yoog raws yuav tsum sib npaug kom tsis txhob nkig.
4.Seal Hom Sib txuam
Mos foob: haum rau qhov tsis tshua muaj siab, huv si, kev ua haujlwm zoo sealing, tab sis tsis muaj kev puas tsuaj
Hard foob: haum rau kev kub siab particle media; foob yog ua tiav los ntawm kev sib cuag nrog hlau
Combined sealing: Muab qhov zoo ntawm cov khoom muag muag thiab tawv tawv xws li lub nplhaib PTFE embedded nyob rau hauv lub rooj zaum hlau valve kom sib npaug tiv thaiv kev puas tsuaj thiab sealing kev ua tau zoo.
