1. Vim li cas cov khoom sib khi tseem ceeb
Cov khoom sib khi - feem ntau hu ua lub nplhaib lub rooj zaum lossis lub rooj zaum saum npoo - yog cov khoom siv ntawm lub valve uas ncaj qha mus rau cov kav dej nruab nrab thiab tiv thaiv kev xau ntawm cov neeg kaw ( rooj vag, disc, pob, ntsaws) thiab lub cev. Nws yuav tsum tiv taus qhov nruab nrab chemically, ciaj sia nyob rau hauv qhov kev pab cuam kub thiab siab, zam rov qab kaw cycles, thiab nyob twj ywm dimensionally ruaj khov rau lub valve lub neej tsim. Lub rooj zaum tsis ncaj ncees lawm yog ib qho ua rau ua rau tsis ua haujlwm ntxov ntxov: nws tuaj yeem o los yog yaj hauv nruab nrab, extrude nyob rau hauv siab, embrittle ntawm qhov kub thiab txias, los yog erode nyob rau hauv abrasive txaus. Cov ntaub ntawv sib khi muab faib ua ob tsev neeg dav -tsis yog{0}}hlau(elastomers, plastics, graphite) thiabnws yog xim hlau(cam khwb cia hlau, tooj liab alloys, stainless hlau, nyuaj-fab thiab nto-kho alloys). Tsis yog-cov ntsaws ruaj ruaj yog feem ntau xaiv rau kev kaw ntom nti ntawm qhov kub thiab txias; hlau ntsaws ruaj ruaj yog xaiv rau qhov kub thiab txias, siab siab, aggressive media, los yog qhov twg hluav taws kev ruaj ntseg yuav tsum tau hlau-rau- hlau kaw.
2. Tsis yog-Cov khoom siv hlau sib khi
| Khoom siv | Hom kub ntau yam | Hom siab | Cov kev pabcuam |
|---|---|---|---|
| EPDM | ≈ -40 rau 120 degree | PN Tsawg dua lossis sib npaug rau 16 yam | Dej, chav dej (limited), HVAC, tshuaj me me; zoo heev ozone / huab cua tsis kam |
| Nitrile (NBR) | ≈ -30 rau 120 degree | PN Tsawg dua lossis sib npaug rau 16 yam | Roj, roj, dej; tsis zoo ozone kuj |
| FKM (fluororubber) | ≈ -20 rau 200 degree | PN Tsawg dua lossis sib npaug rau 16–25 raug | Cov tshuaj nruj nruj, roj kub, kev pabcuam hydrocarbon |
| PTFE / RPTFE khoom | ≈ −60 txog 180–200℃nruam (260℃luv-lub sijhawm) | PN Tsawg dua lossis sib npaug li 40 nyob ntawm tus qauv tsim | Cov tshuaj corrosive, chav ua haujlwm, rooj zaum dav dav; kev sib txhuam tsawg; RPTFE (iav / carbon ntim) txhim kho kev nkag thiab hnav |
| PEB | Lub kaum sab xis ntawm lub kaum sab xis yog 260 degree | Kev kub siab muaj peev xwm | Siab-lub rooj zaum kub hauv pob thiab npauj npaim li qub; muaj zog, hnav-resistant |
| Nylon (PA) thiab lwm yam yas yas | ≈ Tsawg dua lossis sib npaug li 90-120 degree | Tsim - nyob ntawm | Tsawg-cov rooj zaum kub, cov lus qhia thiab cov khoom hnav; txheeb xyuas qhov ntsuas siab tiv thaiv tus qauv tsim |
| Saj zawg zog graphite | ≈ -200 txog 450℃+ (inert media) | Tsim - nyob ntawm | Ntim thiab siab -lub rooj zaum kub; zoo thermal stability, tsis muaj zog oxidizers |
Ob daim ntawv xaiv: elastomer kub txwv poob thaum nruab nrab yog cov kuab tshuaj los yog dej kub (hydrolysis), yog li nco ntsoov xyuas daim ntawv qhia kev sib raug zoo rau cov xov xwm tiag tiag, tsis yog qhov kub thiab txias; thiab sau PTFE (RPTFE) los yog PEEK yog nyiam qhov twg los xij, hnav lossis siab siab koom nrog, vim tias tsis muaj PTFE deforms nyob rau hauv load.
3. Cov khoom siv hlau sealing
Cov rooj zaum hlau tau teev tseg thaum qhov kub siab tshaj li elastomer / yas txwv, thaum nruab nrab tawm tsam polymers, thaum cov khoom yuav rhuav lub rooj muag muag, lossis thaum hluav taws kub - yuav tsum tau kaw kom zoo. Cov tsev neeg:
Cam khwb cia hlau:tsawg-cov rooj zaum raug nqi rau lub rooj vag thiab lub ntiaj teb li qub hauv dej, roj thiab roj kev pabcuam ntawm qhov kub nruab nrab (txog Tsawg dua lossis sib npaug li 100 degree) thiab siab (PN Tsawg dua lossis sib npaug rau 16 tus qauv).
Copper alloys (bronze / tooj dag):Piv txwv li, tin bronze thiab manganese tooj dag qib - zoo hnav tsis kam thiab corrosion kuj nyob rau hauv dej thiab chav (txog tsawg dua los yog sib npaug rau 200 degree, PN Tsawg dua los yog sib npaug rau 16-25 raug); dav siv nyob rau hauv rooj vag, ntiaj teb, kos thiab ntsaws li qub rau cov dej ua haujlwm.
Martensitic stainless hlau (xws li GB 2Cr13 / 3Cr13, kwv yees ASTM 420):quenched thiab tempered rau hardness thiab corrosion kuj; ib lub rooj zaum khoom siv rau dej, chav dej thiab roj av kev pabcuam txog li 450 degree.
Chromium-nickel{1}}titanium stainless (GB 1Cr18Ni9Ti, kwv yees li ASTM 321):corrosion-, yaig- thiab kub-resistant; siv nyob rau hauv lub ntiaj teb thiab pob valve rooj rau chav thiab corrosive media ntawm qhov kub thiab txias.
Nitriding hlau (GB 38CrMoAlA):nitrided nto muab siab hardness thiab abrasion tsis kam; siv nyob rau hauv lub hwj chim- cog qhov rooj li qub thiab siab - cov kev pab cuam caij tsheb kauj vab.
Nyuaj- ntsej muag overlays:cobalt-raws li (Co–Cr–W hom) los yog npib tsib xee-raws li alloys siv los ntawm vuam rau lub rooj rings thiab kaw npoo - tus txheej txheem tov rau siab - siab poob, erosive los yog siab - kub sealing nto.
Boronized (boronized) nto:diffusion kho uas hardens lub rooj saum npoo ncaj qha rau ntawm lub cev lossis cov khoom siv disc; siv qhov twg xav tau kev puas tsuaj loj heev (piv txwv li, tshauv- tuav thiab tso dej).
Cov rooj zaum hlau foob los ntawm precision machining es tsis yog deformation, yog li lawv raug ntsuas rau cov chav kawm to taub tsis yog "zero to"; qhov yuav tsum tau kaw nruj nreem ntxiv rau qhov kub thiab txias, muab lub rooj zaum hlau nrog lub graphite lossis hluav taws kub -kev nyab xeeb thib ob, lossis siv lub rooj zaum rov qab- tsim lub rooj zaum hauv nws lub hnab ntawv.
4. Media Compatibility Xaiv Rooj
| Media | Lub rooj zaum | Zam |
|---|---|---|
| Dej txias / dej kub | EPDM, PTFE, tooj liab | NBR (tsis zoo kub- dej lub neej) |
| Chav | Hlau, graphite, PEEK (hauv txwv) | EPDM / NBR (hydrolysis), unfilled PTFE ntawm kev kub siab kub |
| Hydrocarbons / roj | NBR, FKM, PTFE, hlau | EPDM (roj swelling) |
| Muaj zog acids / alkali | PTFE / RPTFE, PEEK, tshwj xeeb alloys | NBR / EPDM (tshuaj tua kab mob) |
| Abrasive slurries | Hlau nrog nyuaj tig, borided nto | Mos elastomers (tuag) |
| Cryogenic media | PTFE (nyob rau hauv txwv), stainless hlau rooj | Elastomers (Elastomers) |
| Hluav taws kub- yuav tsum muaj kev nyab xeeb | Hlau rooj (thawj lossis theem nrab ntawm API 607) | Mos- rooj zaum- tsuas yog tsim |
5. Cov hom kev ua tsis tau zoo thiab cov cai siv tau
Plaub hom kev ua tsis tiav rov tshwm sim yog:kev yaig(cov khoom los yog siab tshaj tawm txiav lub rooj zaum - mitigate nrog nyuaj tig thiab ceev tswj);extrusion(cov rooj zaum muag muag nyem rau hauv qhov kev tshem tawm hauv siab - txo qis nrog kev tiv thaiv- cov nplhaib extrusion lossis qib puv);Kev laus / hydrolysis(elastomers hardened los yog o los ntawm cov xov xwm thiab kub - mitigate nrog raug polymer xaiv thiab hloov lub sij hawm); thiabsiab(hlau-rau-hlau nto seize nyob rau hauv qhuav los yog siab- qhov kub thiab txias kev pab cuam - mitigate nrog dissimilar cov ntaub ntawv los yog nyuaj nyuaj). Peb txoj cai siv tau: (1) qhia cov khoom siv lub rooj zaum, tsis yog cov khoom siv lub cev xwb, ntawm txhua qhov kev txiav txim - lub rooj zaum yog qhov hnav; (2) sim kev sib khi ua haujlwm ntawm kev ua haujlwm thiab rov- xyuas lub rooj zaum ntawm txhua lub sijhawm txij nkawm, hloov cov rooj zaum hnav ua ntej yuav tawg; (3) Tsis txhob ntxiv cov khoom siv qhov kub thiab txias rau qhov nruab nrab sib txawv - daim ntawv qhia kev sib raug zoo rau cov xov xwm tiag tiag yog cov ntaub ntawv tswj hwm.
6. FAQ
Mos foob lossis hlau foob - uas zoo dua?Tsis yog universally zoo dua. Cov ntsaws ruaj ruaj (elastomers, PTFE) muab npuas - nruj kaw ntawm nruab nrab kub / siab; hlau ntsaws ruaj ruaj muaj sia nyob qhov kub thiab txias, siab, yaig thiab hluav taws kub, nrog rau cov chav kawm to taub. Xaiv los ntawm lub luag haujlwm, tsis nyiam.
Lub rooj zaum PTFE tuaj yeem tiv taus li cas?Feem ntau hais txog −60 txog 180-200℃txuas ntxiv, nrog 260℃raws li luv luv -lub sij hawm siab tshaj plaws hauv qee daim ntawv thov. Cov qib puv (RPTFE) txhim kho kev nkag thiab hnav; rau qhov kub siab dua txav mus rau PEEK lossis rooj zaum hlau.
Dab tsi yog qhov txawv ntawm EPDM thiab NBR seals?EPDM tiv taus dej, ncu, huab cua thiab ozone tab sis swells hauv roj; NBR tiv taus roj thiab roj tab sis ua haujlwm tsis zoo hauv ozone thiab dej kub. Sib piv cov polymer rau hauv daim ntawv xov xwm, tsis yog cwj pwm.
Cov khoom siv lub rooj zaum twg yog siv rau chav ua haujlwm?Rau saturated chav, EPDM ua haujlwm nyob rau hauv nws qhov kub thiab txias (txog 120 degree); saum toj no uas siv PTFE (hauv txwv), PEEK, graphite lossis hlau rooj. Txheeb xyuas qhov siab- qhov ntsuas kub tsis pub dhau qhov ntsuas lub valve.
"hluav taws- nyab xeeb" txhais li cas rau lub rooj zaum valve?hluav taws-kev nyab xeeb valve muaj lub rooj zaum hlau thib ob uas tswj tau qhov kev foob zoo tom qab lub rooj muag muag raug tua los ntawm hluav taws, muaj ntawv pov thawj API 607 (mos-lub quarter-tig) lossis API 6FA - xav tau rau hydrocarbon thiab siab - cov kev pabcuam pheej hmoo.
Kuv yuav tiv thaiv lub rooj extrusion hauv siab - kev pabcuam siab li cas?Siv cov PTFE (RPTFE), PEEK, lossis hlau rooj; haum anti-extrusion thaub qab rings; thiab paub meej tias lub rooj zaum tsim kev tshem tawm sib tw nrog cov chav kawm siab. Nug cov chaw tsim khoom rau kev tsim lub rooj zaum ntawm koj lub siab.
Qhia rau peb koj cov xov xwm, qhov kub thiab txias - peb yuav qhia kom meej cov khoom sealing zoo thiab valve trim.
Cov lus nug nquag
Yam twg uas tsis yog - cov khoom siv hlau yog haum rau cov tshuaj lom neeg thiab cov roj kub siab tshaj qhov txwv elastomer?FKM (fluororubber) yog tus qauv kev xaiv rau cov tshuaj nruj heev, cov roj kub thiab cov kev pabcuam hydrocarbon, nrog rau ntau yam ntawm −20 txog 200 degree. Tshawb xyuas qhov nruab nrab tiag tiag tiv thaiv cov chaw tsim khoom siv daim ntawv qhia, vim tias cov kev txwv elastomer poob rau hauv cov kuab tshuaj thiab cov dej kub txawm nyob rau hauv qhov ntsuas kub nominal.
Vim li cas RPTFE thiaj nyiam tshaj PTFE uas tsis tau ua tiav rau siab dua - lub rooj zaum siab?Unfilled PTFE deforms nyob rau hauv load, yog li unfilled rooj nkag thiab hnav sai sai ntawm siab dua. Iav- lossis carbon- puv PTFE (RPTFE) txhim kho kev nkag siab thiab coj tus cwj pwm, thiab PEEK yog qhov nyiam qhov uas lub luag haujlwm tseem xav tau ntau dua.
Thaum twg yog graphite saj zawg zog siv los ua lub valve sealing khoom?Saj zawg zog graphite suits packing thiab siab - rooj zaum kub, nrog zoo thermal stability ntawm li -200 mus rau 450℃thiab siab tshaj nyob rau hauv inert media. Nws yog ib qho kev xaiv tsis zoo nyob rau hauv cov oxidizers muaj zog, yog li paub meej tias nruab nrab compatibility ua ntej qhia nws.
Vim li cas cov rooj zaum hlau raug ntsuas rau cov chav kawm uas tau hais tseg es tsis yog xoom xau?Cov rooj zaum hlau foob los ntawm precision machining es tsis yog deformation, yog li lawv tau sim rau cov chav kawm uas tau hais tseg tsis txhob ua npuas - nruj kaw. Thaum kaw nruj nreem thiab kub siab yog ob qho tib si yuav tsum tau ua, muab lub rooj zaum hlau nrog graphite lossis hluav taws kub -kev nyab xeeb thib ob, lossis siv lub rooj zaum zoo - lub rooj tsim hauv nws lub hnab ntawv.
Cov rooj zaum tawv li cas rau abrasive slurry thiab tshauv -kev pabcuam?Cobalt-raws li los yog npib tsib xee-raws li nyuaj-fab alloys yog siv los ntawm vuam rau lub rooj rings thiab kaw ntug, thiab borided (boronized) diffusion kho hardens lub rooj saum npoo ncaj qha rau ntawm lub cev los yog cov ntaub ntawv disc. Ob leeg yog cov qauv kev daws teeb meem rau siab -siab-poob, erosive thiab tshauv- tuav haujlwm.
Dab tsi yog lub rooj zaum ntau tshaj - cuam tshuam ua rau lub valve tsis ua haujlwm ntxov?Cov khoom siv tsis yog lub rooj zaum yog qhov ua rau ntau tshaj plaws: nws tuaj yeem o lossis yaj hauv qhov nruab nrab, extrude nyob rau hauv siab, embrittle ntawm qhov kub thiab txias, los yog erode hauv abrasive txaus. Qhia cov khoom siv lub rooj zaum nrog rau cov khoom siv lub cev ntawm txhua qhov kev txiav txim, thiab rov- xyuas lub rooj zaum ntawm txhua lub sijhawm tu.