Lub Luag Haujlwm thiab Cov Ntsiab Cais Tseem Ceeb ntawm Gasket
Lub gasket ntawm flange ua haujlwm los ntawm kev raug压缩 nyob rau hauv bolt preload los sau cov irregularities hauv flange facing surfaces. Lub compressive stress yuav tsum siab txaus los tsim ib qho kev sib khi (seal) tab sis qis txaus kom tsis txhob puas tsuaj rau gasket los yog flange. Lub gasket kuj yuav tsum ua tau raws li kev txav ntawm ob lub flange uas tshwm sim los ntawm thermal expansion, pressure-induced forces, thiab external piping loads. Kev xaiv hom gasket lossis khoom siv tsis raug yuav ua rau muaj kev xau (leakage), fugitive emissions, thiab tej zaum yuav ua rau lub system tsis ua haujlwm.
Cov Gasket Uas Tsis Yog Hlau (Non-Metallic Gaskets)
Cov gasket uas tsis yog hlau yog tsim los ntawm cov khoom uas compressible tau thiab feem ntau yog siv rau hauv qhov chaw uas muaj siab qis thiab kub qis. Rubber (elastomer) gaskets ua haujlwm rau qhov kub qis thiab siab qis txog 400°F. PTFE gaskets muaj kev tiv thaiv tshuaj zoo heev thoob plaws qhov pH dav txog 500°F. Flexible graphite gaskets tswj tau qhov kub siab txog 850°F nrog kev tiv thaiv tshuaj zoo. Compressed non-asbestos fiber (CNAF) gaskets yog ib qho kev xaiv dav dav rau cov xwm txheej nruab nrab. Qhov kev txwv tseem ceeb ntawm cov gasket uas tsis yog hlau yog lawv muaj peev xwm tsis tau siab thiab muaj feem yuav tawg (blowout) thaum muaj siab siab.
| Hom Gasket | Qhov Kub Siab Tshaj Plaws | Qeb Siab Siab Tshaj Plaws | Kev Tiv Thaiv Tshuaj | Tus Nqi Sib Piv |
|---|---|---|---|---|
| Elastomer (NBR, EPDM) | 400°F | 150 | Zoo (rau cov tshuaj tshwj xeeb) | Qis |
| PTFE | 500°F | 300 | Zoo heev (txhua yam tshuaj) | Nruab Nrab |
| Flexible Graphite | 850°F | 600 | Zoo (txwv tsis txhob siv nrog cov oxidizers muaj zog) | Nruab Nrab |
| CNAF | 700°F | 300 | Zoo (rau kev siv dav dav) | Qis |
Cov Gasket Uas Yog Ib Nrab Hlau (Semi-Metallic Gaskets)
Cov gasket uas yog ib nrab hlau muab lub zog ntawm hlau los sib txuas nrog cov khoom nplaum mos (soft filler) los ua kev sib khi. Spiral wound gaskets yog hom uas nrov tshaj plaws ntawm cov semi-metallic, muaj cov txheej hlau thiab cov khoom nplaum mos uas tig ua kauv (spiral). Lawv feem ntau muaj cov nplhaib sab hauv thiab sab nraud rau kev ua kom nruab nrab thiab txhawb nqa. Metal jacketed gaskets muaj cov khoom nplaum mos nyob hauv plawv thiab muaj hlau vov sab nraud. Camprofile (Kammprofile) gaskets muaj ib lub hauv paus hlau uas muaj cov kab txaib (grooved) thiab muaj graphite lossis PTFE vov. Semi-metallic gaskets tsim nyog rau qhov siab nruab nrab mus rau siab thiab kub txog Class 1500.
Cov Gasket Hlau (Metallic Gaskets)
Cov gasket hlau muab kev ruaj ntseg siab tshaj plaws rau cov kev pabcuam tseem ceeb. Ring joint gaskets yog cov nplhaib hlau tawv uas tsim los rau RTJ flange facings. Lawv deformation rau hauv lub groove thaum muaj bolt load los tsim ib qho kev sib khi hlau-rau-hlau. Muaj cov duab oval thiab octagonal rau cov qauv groove sib txawv. Solid metal flat gaskets yog siv rau qhov kub los yog siab txawv heev. Cov khoom gasket yuav tsum mos dua li cov khoom flange kom tsis txhob puas tsuaj rau flange face, thiab kev xaiv hlau yuav tsum xav txog kev sib haum nrog galvanic corrosion nrog cov khoom flange.
Cov Lus Qhia Rau Kev Xaiv Khoom Siv
Qhov kub yog feem ntau yog qhov tseem ceeb: elastomers txog 400°F, PTFE txog 500°F, graphite txog 900°F, thiab hlau txog 1800°F. Kev sib haum nrog tshuaj yog qhov tseem ceeb: PTFE rau cov tshuaj muaj zog, graphite rau alkalis, thiab stainless steel rau kev siv corrosive dav dav. Qhov muaj peev xwm siab ua raws li qhov hierarchy: cov gasket uas tsis yog hlau txog Class 300, semi-metallic gaskets txog Class 1500, thiab cov gasket hlau rau Class 2500. Tus nqi kuj ua raws li tus qauv no: cov uas tsis yog hlau pheej yig tshaj plaws, cov hlau kim tshaj plaws.
Qhov Ntsuas thiab Cov Qauv (Standards)
ASME B16.20 npog cov qhov ntsuas ntawm metallic thiab spiral wound gaskets, thaum ASME B16.21 npog cov non-metallic flat gaskets. Qhov ntsuas sab hauv thiab sab nraud ntawm gasket yuav tsum phim cov qhov ntsuas flange facing. Rau spiral wound gaskets, lub nplhaib sab hauv muab kev ua kom nruab nrab thiab tiv thaiv kom tsis txhob poob los rau hauv, thaum lub nplhaib sab nraud ua haujlwm ua ib qho chaw nres kom tsis txhob nias dhau. Kev ntsuas gasket kom raug yuav ua kom lub gasket zaum kom raug hauv lub voj bolt thiab kom lub sealing stress faib tau sib npaug.
Cov Tswv Yim Zoo Tshaj Plaws Rau Kev Teeb Tsa
Ntxuav ob lub flange faces kom huv thiab xyuas tsis muaj kev puas tsuaj ua ntej teeb tsa ib lub gasket tshiab. Siv bolt torque kom raug nyob rau hauv ib qho kev sib tw (cross-bolting sequence) los xyuas kom lub gasket compression sib npaug. Tsis txhob nias dhau qhov uas cov tuam txhab gasket pom zoo, vim kev nias dhau tuaj yeem ua rau lub gasket puas thiab ua rau xau. Ib txwm siv cov gasket tshiab rau txhua qhov kev sib dhos dua, thiab xyuas kom lub gasket nyob nruab nrab ntawm lub voj bolt ua ntej nruj. Ua raws li cov tswv yim no yuav ua kom qhov sib txuas ruaj khov thiab ua haujlwm ntev npaum li possibl
Xav Tau Kev Pab Xaiv Gasket?
Hu rau peb pab neeg engineering rau kev pab xaiv flange gasket kom raug rau koj li kev siv tshwj xeeb.
Cov Khoom Flange
