Nakuba amavalvu epulasitiki ngezinye izikhathi abonwa njengomkhiqizo okhethekile—inketho ephezulu yalabo abenza noma abaklama imikhiqizo yamapayipi epulasitiki yezinhlelo zezimboni noma okufanele babe nezinto ezihlanzekile kakhulu endaweni—ukuthatha ukuthi la mavalvu awanawo amaningi asetshenziswayo kufushane- obonayo. Eqinisweni, ama-valve epulasitiki namuhla anezinhlobonhlobo zokusetshenziswa njengoba izinhlobo ezikhulayo zezinto kanye nabaklami abahle abadinga lezo zinto zisho izindlela eziningi zokusebenzisa la mathuluzi ahlukahlukene.
IMPAHLA YE-PLASTIC
Izinzuzo zama-valve e-thermoplastic zibanzi-ukugqwala, ukumelana namakhemikhali nokuhuzuka; izindonga ezibushelelezi zangaphakathi; isisindo esincane; kalula ukufakwa; ubude bempilo ende; kanye nezindleko eziphansi zomjikelezo wempilo. Lezi zinzuzo ziye zaholela ekwamukelweni okubanzi kwama-valve epulasitiki ekusetshenzisweni kwezentengiselwano nezimboni njengokusatshalaliswa kwamanzi, ukwelashwa kwamanzi angcolile, ukucutshungulwa kwensimbi namakhemikhali, ukudla nemithi, izitshalo zamandla, izindawo zokuhluza uwoyela nokunye.
Ama-valve epulasitiki angenziwa ngenani lezinto ezihlukahlukene ezisetshenziswa eziningana zokucupha. Amavalvu e-thermoplastic avame kakhulu enziwe nge-polyvinyl chloride (PVC), i-chlorinated polyvinyl chloride (CPVC), i-polypropylene (PP), ne-polyvinylidene fluoride (PVDF). Amavalvu e-PVC kanye ne-CPVC ajwayele ukujoyinwa ezinhlelweni zamapayipi ngokusebenzisa iziphetho zesokhethi ye-solvent, noma iziphetho ezinentambo nezine-flanged; kanti, i-PP ne-PVDF zidinga ukuhlanganiswa kwezingxenye zesistimu yamapayipi, kungaba ngobuchwepheshe bokushisa, i-butt- noma i-electro-fusion.
Amavalvu e-Thermoplastic ahamba phambili endaweni ebolayo, kodwa awusizo ngendlela efanayo kusevisi yamanzi evamile ngoba awanawo umthofu1, amelana nokubola futhi ngeke agqwale. Amasistimu namavalvu amapayipi e-PVC kanye ne-CPVC kufanele ahlolwe futhi anikezwe isitifiketi ku-NSF [National Sanitation Foundation] standard 61 ukuze uthole imiphumela yezempilo, okuhlanganisa nemfuneko ephansi yomthofu ye-Annex G. Ukukhetha into efanele yoketshezi olubolayo kungasingathwa ngokuthintana nomkhiqizi ukumelana namakhemikhali. liqondise futhi liqonde umphumela izinga lokushisa elizoba nawo phezu kwamandla ezinto zepulasitiki.
Nakuba i-polypropylene inengxenye yamandla e-PVC ne-CPVC, inokumelana namakhemikhali okuhlukahlukene kakhulu ngenxa yokuthi azikho izincibilikisi ezaziwayo. I-PP yenza kahle kuma-acetic acid nama-hydroxide agxilile, futhi ilungele izixazululo ezithambile zama-asidi amaningi, ama-alkali, usawoti kanye namakhemikhali amaningi emvelo.
I-PP itholakala njengento enemibala noma engenambala (yemvelo). I-Natural PP yonakaliswa kakhulu imisebe ye-ultraviolet (UV), kodwa izinhlanganisela eziqukethe ngaphezu kuka-2.5% we-carbon black pigmentation azinza ngokwanele i-UV.
Amapayipi e-PVDF asetshenziswa emisebenzini eyahlukene yezimboni kusukela kweyemithi kuye kweyezimayini ngenxa yamandla e-PVDF, izinga lokushisa elisebenzayo kanye nokumelana namakhemikhali kusawoti, ama-asidi aqinile, izisekelo ezincibilikayo kanye nezinyibilikisi eziningi eziphilayo. Ngokungafani ne-PP, i-PVDF ayonakaliswa ukukhanya kwelanga; nokho, ipulasitiki isobala ekukhanyeni kwelanga futhi ingadalula uketshezi emisebeni ye-UV. Nakuba ukwakheka kwe-PVDF okungokwemvelo, okungenayo i-pigmented kuhle kakhulu ekuhlanzeni okuphezulu, ekufakweni kwasendlini, ukwengeza umbala obomvu njengombala wokudla kungavumela ukuchayeka elangeni ngaphandle komthelela omubi endaweni yoketshezi.
Amasistimu epulasitiki anezinselele zokuklama, njengokuzwela izinga lokushisa kanye nokunwetshwa kokushisa kanye nokuncipha, kodwa onjiniyela bangakwazi futhi baklame amasistimu amapayipi ahlala isikhathi eside, angabizi kakhulu endaweni evamile kanye negqwala. Ukucatshangelwa okukhulu kokuklama ukuthi i-coefficient yokwanda okushisayo kwamapulasitiki inkulu kunensimbi-i-thermoplastic iphindwe kahlanu kuya kweziyisithupha kunensimbi, isibonelo.
Lapho uklama amasistimu amapayipi futhi ucabangela umthelela ekubekweni kwama-valve nezisekelo zamavalvu, ukucatshangelwa okubalulekile ku-thermoplastics ukunwetshwa kokushisa. Ukucindezeleka namandla okubangelwa ukwanda nokufinyela okushisayo kungancishiswa noma kuqedwe ngokunikeza ukuguquguquka kwezinhlelo zamapayipi ngoshintsho oluvamile ekuqondeni noma ukwethulwa kwezihibe zokunweba. Ngokunikeza lokhu kuguquguquka ohlelweni lwamapayipi, i-valve yepulasitiki ngeke kudingeke ukuthi imunce ukucindezeleka okuningi
Ngenxa yokuthi ama-thermoplastic azwela ukushisa, isilinganiso sokucindezela kwe-valve siyehla njengoba izinga lokushisa likhuphuka. Izinto ezihlukene zepulasitiki zine-deration ehambisanayo nezinga lokushisa elikhulayo. Izinga lokushisa eliwuketshezi lingase lingabi ukuphela komthombo wokushisa ongathinta isilinganiso sokucindezela kwamavalvu epulasitiki—izinga lokushisa eliphezulu langaphandle lidinga ukuba yingxenye yokucatshangelwa komklamo. Kwezinye izimo, ukungaklami ukushisa kwangaphandle kwamapayipi kungabangela ukuhlehla ngokweqile ngenxa yokuntuleka kwezisekelo zamapayipi. I-PVC inezinga lokushisa eliphezulu lesevisi elingu-140°F; I-CPVC inobukhulu obungu-220°F; I-PP inobukhulu obungu-180°F; namavalvu e-PVDF angagcina ingcindezi ifike ku-280°F
Ngakolunye uhlangothi lwezinga lokushisa, izinhlelo eziningi zamapayipi epulasitiki zisebenza kahle emazingeni okushisa angaphansi kwezingaqhwa. Eqinisweni, amandla okuqina ayanda kumapayipi e-thermoplastic njengoba izinga lokushisa lincipha. Kodwa-ke, ukumelana komthelela kwamapulasitiki amaningi kuncipha njengoba izinga lokushisa lehla, futhi ukonakala kubonakala ezintweni zamapayipi ezithintekayo. Inqobo nje uma ama-valve nohlelo lwamapayipi axhumene lungaphazamisekile, alufakwa engcupheni ukushaywa noma ukungqubuzana kwezinto, futhi amapayipi angawi ngesikhathi sokuphatha, imiphumela emibi kumapayipi epulasitiki iyancishiswa.
IZINHLOBO ZAMAVAVAVA E-THERMOPLASTIC
Amavalvu ebhola, amavalufu okuhlola, amavalvu ovemvane namavalvu e-diaphragm ayatholakala kuzinto ezihlukene ze-thermoplastic zohlelo lwamapayipi okucindezela angama-80 nawo anenqwaba yezinketho zokunquma kanye nezinsiza. Ivalvu yebhola ejwayelekile itholakala kakhulu iwumklamo wenyunyana wangempela ukusiza ukukhishwa komzimba we-valve ukuze ulungiswe ngaphandle kokuphazamiseka kokuxhuma amapayipi. Ama-valve okuhlola i-Thermoplastic ayatholakala njengamasheke ebhola, amasheke e-swing, ama-y-check kanye namasheke wekhoni. Amavalvu ovemvane ahlangana kalula nama-flange ensimbi ngenxa yokuthi ahambisana nezimbobo zebhawodi, imibuthano yebhawodi kanye nobukhulu bebonke be-ANSI Class 150. Ububanzi obushelelezi bangaphakathi bezingxenye ze-thermoplastic zengeza kuphela ekulawuleni okunembile kwamavalvu e-diaphragm.
Amavalvu ebhola ku-PVC naku-CPVC akhiqizwa izinkampani ezimbalwa zase-US nezakwamanye amazwe ngobukhulu obuyi-1/2 intshi ukuya ku-6 amayintshi anesokhethi, axhumene nentambo noma ane-flanged. Idizayini yangempela yenyunyana yamavalvu ebhola esimanje ihlanganisa amantongomane amabili ajiya emzimbeni, ecindezela ama-elastomeric seal phakathi komzimba nezixhumi zasekugcineni. Abanye abakhiqizi bagcine ivalve yebhola efanayo yokubeka ubude kanye nentambo yamantongomane amashumi eminyaka ukuvumela ukushintshwa kalula kwamavalvu amadala ngaphandle kokuguqulwa kumapayipi axhumene.
Amavalvu ebhola ane-ethylene propylene diene monomer (EPDM) ama-elastomeric seals kufanele aqinisekiswe ku-NSF-61G ukuze asetshenziswe emanzini aphuzwayo. I-Fluorocarbon (FKM) izigxivizo ze-elastomeric zingasetshenziswa njengenye indlela yezinhlelo lapho ukuhambisana kwamakhemikhali kuwukukhathazeka. I-FKM futhi ingasetshenziswa ezinhlelweni eziningi ezibandakanya ama-asidi amaminerali, ngaphandle kwe-hydrogen chloride, izixazululo zikasawoti, ama-hydrocarbon ane-chlorine namafutha e-petroleum.
Amavalvu ebhola e-PVC kanye ne-CPVC, 1/2-intshi ukuya kumayintshi angu-2, ayinketho esebenzayo yokufakwa kwamanzi ashisayo nabandayo lapho isevisi enkulu yamanzi angashaqisi ingaba yinkulu njengo-250 psi ku-73°F. Ama-valve amabhola amakhulu, ama-intshi angu-2-1/2 ukuya kwangu-6 amayintshi, azoba nengcindezi ephansi yokukala engu-150 psi ku-73°F. Okuvamise ukusetshenziswa ekudluliseni amakhemikhali, amavalvu ebhola e-PP kanye ne-PVDF (Izibalo 3 kanye no-4), atholakala ngosayizi 1/2-intshi ukuya kumayintshi angu-4 anesokhethi, oxhumo olunentambo noma olune-flanged-end ngokuvamile akalwa kusevisi yamanzi angathuki. 150 psi ekushiseni kwe-ambient.
Ama-valve okuhlola amabhola e-Thermoplastic ancike ebholeni eline-gravity ethize engaphansi kwaleyo yamanzi, ukuze kuthi uma ukucindezela kulahleka ohlangothini olusenhla nomfula, ibhola lizocwila libuyele endaweni yokuvala. Lawa ma-valve angasetshenziswa enkonzweni efanayo nama-valve ebhola epulasitiki afanayo ngoba awethuli izinto ezintsha ohlelweni. Ezinye izinhlobo zama-valve okuhlola zingase zihlanganise iziphethu zensimbi ezingase zingahlali endaweni ezonakalisayo.
Ivalve uvemvane wepulasitiki ngobukhulu amayintshi ama-2 ukuya kumayintshi angu-24 idumile kumasistimu amapayipi amakhulu obubanzi. Abakhiqizi bamavalvu evemvane epulasitiki bathatha izindlela ezihlukene zokwakha kanye nokuvala izindawo. Abanye basebenzisa i-elastomeric liner (Umfanekiso 5) noma i-O-ring, kuyilapho abanye basebenzisa i-elastomeric-coated disc. Abanye benza umzimba ngento eyodwa, kodwa izakhi zangaphakathi, ezimanzi zisebenza njengezinto zesistimu, okusho ukuthi umzimba wevalve uvemvane we-polypropylene ungase uqukathe umugqa we-EPDM kanye nediski ye-PVC noma okunye ukulungiselelwa okuvame ukutholakala nge-thermoplastics kanye ne-elastomeric seals.
Ukufakwa kwe-valve uvemvane lwepulasitiki kuqondile ngoba lawa mavalvu enziwe abe yisitayela se-wafer esinama-elastomeric seals aklanywe emzimbeni. Abadingi ukungezwa kwe-gasket. Kubekwe phakathi kwama-flange amabili okukhwelana, ukuboliswa phansi kwe-valve uvemvane lwepulasitiki kufanele kusingathwe ngokucophelela ngokukhuphukela kuthoshi yebhawodi enconyiwe ngezigaba ezintathu. Lokhu kwenzelwa ukuqinisekisa uphawu olulinganayo endaweni yonke futhi kungabikho ukucindezelwa komshini okungalingani okufakwa ku-valve.
Ochwepheshe bamavalvu ensimbi bazothola imisebenzi ephezulu yamavalvu epulasitiki e-diaphragm anezinkomba zesondo nezendawo ezijwayelekile (Umfanekiso 6); kodwa-ke, i-valve yepulasitiki ye-diaphragm ingabandakanya izinzuzo ezithile ezihlukene ezihlanganisa izindonga ezibushelelezi zangaphakathi zomzimba we-thermoplastic. Ngokufanayo ne-valve yebhola lepulasitiki, abasebenzisi balawa mavalvu banenketho yokufaka idizayini yangempela yenyunyana, engaba usizo ikakhulukazi emsebenzini wokunakekela i-valve. Noma, umsebenzisi angakhetha ukuxhumana okune-flanged. Ngenxa yazo zonke izinketho zomzimba kanye ne-diaphragm materials, le valve ingasetshenziswa ezinhlobonhlobo zamakhemikhali.
Njenganoma iyiphi i-valve, ukhiye wamavalvu epulasitiki asebenza ukunquma izidingo zokusebenza ezifana ne-pneumatic ngokumelene nogesi kanye ne-DC ngokumelene namandla e-AC. Kepha ngepulasitiki, umklami nomsebenzisi kufanele futhi baqonde ukuthi hlobo luni lwendawo ezozungeza i-actuator. Njengoba kushiwo ngaphambili, ama-valve epulasitiki ayindlela enhle yezimo ezonakalisayo, ezihlanganisa izindawo ezilimazayo zangaphandle. Ngenxa yalokhu, izinto zezindlu zama-actuator zama-valve epulasitiki ziwukucatshangelwa okubalulekile. Abakhiqizi bamavalvu epulasitiki banezinketho zokuhlangabezana nezidingo zalezi zindawo ezonakalisayo ngendlela yama-actuator embozwe ngepulasitiki noma amakesi ensimbi ane-epoxy.
Njengoba lesi sihloko sibonisa, ama-valve epulasitiki namuhla anikeza zonke izinhlobo zezinketho zezinhlelo zokusebenza ezintsha nezimo
Isikhathi sokuthumela: Jul-30-2020