Lapho Kusetshenziswa Amavalvu: Yonke indawo!

08 Nov 2017 Ibhalwe uGreg Johnson

Ama-valve angatholakala cishe noma yikuphi namuhla: emakhaya ethu, ngaphansi komgwaqo, ezakhiweni zezentengiselwano kanye nezinkulungwane zezindawo ezingaphakathi kwezimboni zikagesi namanzi, izigayo zamaphepha, izindawo zokuhluza, izitshalo zamakhemikhali nezinye izinsiza zezimboni kanye nengqalasizinda.
Imboni yamavalvu inamahlombe abanzi ngempela, enezingxenye ezihlukayo ukusuka ekusatshalalisweni kwamanzi kuye kumandla enuzi kuye phezulu naphansi komfula kanye nowoyela negesi. Ngayinye yalezi zimboni zabasebenzisi bokugcina isebenzisa ezinye izinhlobo eziyisisekelo zamavalvu; nokho, imininingwane yokwakha kanye nezinto ezisetshenziswayo ngokuvamile ihluke kakhulu. Nasi isampula:

AMANZI ASEBENZA
Ezweni lokusatshalaliswa kwamanzi, izingcindezi zihlale ziphansi futhi amazinga okushisa ajwayelekile. Lawo maqiniso amabili okusebenza avumela inani lezinto zokwakheka kwamavalvu ebezingeke zitholwe emishinini enenselelo eyengeziwe njengama-valve okushisa aphezulu. Izinga lokushisa elizungezile lesevisi yamanzi livumela ukusetshenziswa kwama-elastomer nama-rubber seal angafanele kwenye indawo. Lezi zinto ezithambile zivumela ama-valve amanzi ukuthi afakwe ukuze avale ngokuqinile ama-drip.

Okunye okucatshangelwayo kuma-valve wenkonzo yamanzi ukukhetha ezintweni zokwakha. Ama-ayina ama-cast kanye nama-ductile asetshenziswa kakhulu ezinhlelweni zamanzi, ikakhulukazi imigqa emikhulu yangaphandle yobubanzi. Imigqa emincane kakhulu ingaphathwa kahle ngezinto zevalvu yethusi.

Izingcindezi ezibonwa amavalvu amaningi okusebenza kwamanzi ngokuvamile zingaphansi kuka-200 psi. Lokhu kusho ukuthi amadizayini anezindonga ezinkulu ezinomfutho omkhulu awadingeki. Lokho sekushiwo, kunezimo lapho ama-valve amanzi akhiwe ukuze abambe izingcindezi eziphakeme, aze afike ku-300 psi. Lezi zinhlelo zokusebenza zivame ukuba semiseleni emide eduze nomthombo wengcindezi. Kwesinye isikhathi ama-valve amanzi anomfutho ophakeme nawo atholakala ezindaweni zokucindezela okukhulu edamini elide.

I-American Water Works Association (AWWA) ikhiphe imininingwane ehlanganisa izinhlobo eziningi ezahlukene zamavalvu nama-actuator asetshenziswa ezinhlelweni zokusebenza kwamanzi.

AMANZI AMANZI
Uhlangothi oluphendukile lwamanzi ahlanzekile aphuzwayo olungena endaweni noma esakhiweni amanzi angcolile noma okukhipha indle. Le migqa iqoqa wonke uketshezi olulahlwayo kanye nezinto eziqinile bese ikuqondisa endaweni yokuhlanza indle. Lezi zitshalo zokwelapha zifaka amapayipi amaningi anengcindezi ephansi kanye namavalvu ukwenza “umsebenzi wazo ongcolile.” Izidingo zamavalvu amanzi angcolile ezimweni eziningi zilula kakhulu kunezidingo zesevisi yamanzi ahlanzekile. Isango lensimbi nama-valve okuhlola yizinqumo ezidume kakhulu zalolu hlobo lwenkonzo. Amavalvu ajwayelekile kule sevisi akhiwe ngokuhambisana nokucaciswa kwe-AWWA.

INDUSTRI YAMANDLA
Amandla kagesi amaningi akhiqizwa e-United States akhiqizwa ezitshalweni zesitimu kusetshenziswa iziphethiloli zamandulo kanye nama-turbines anesivinini esikhulu. Ukuhlehlisa ikhava yesikhungo sikagesi sesimanje kuzonikeza umbono wezinhlelo zamapayipi ezinomfutho ophezulu, nezinga lokushisa eliphezulu. Le migqa esemqoka iyona ebaluleke kakhulu enqubweni yokuphehla ugesi ngesitimu.

Amavalvu esango ahlala eyinketho eyinhloko yemishini yokuvula/ukuvala izinhlelo zokusebenza, nakuba inhloso ekhethekile, amavalvu eglobhu ye-Y-pattern nawo ayatholakala. Amavalvu ebhola asebenza kahle, asebenza kanzima athola ukuduma kwabanye abaklami bemishini yamandla futhi ayangenelela kulo mhlaba owake wabuswa ngamavalvu omugqa.

I-Metallurgy ibalulekile kumavalvu ekusetshenzisweni kwamandla, ikakhulukazi lawo asebenza kububanzi obusebenzayo obuphezulu kakhulu noma obuphezulu kakhulu bengcindezi nezinga lokushisa. I-F91, F92, C12A, kanye nama-Inconel amaningana kanye nama-alloys ensimbi engagqwali avame ukusetshenziswa ezitshalweni zamandla zanamuhla. Izigaba zokucindezela zihlanganisa u-1500, 2500 futhi kwezinye izimo 4500. Imvelo yokumodela yezitshalo zamandla aphezulu (lezo ezisebenza kuphela njengoba kudingeka) futhi ibeka ubunzima obukhulu kuma-valve namapayipi, okudinga imiklamo eqinile yokusingatha inhlanganisela eyeqisayo yokugibela amabhayisikili, izinga lokushisa kanye ingcindezi.
Ngaphezu kwe-valving eyinhloko ye-steam, izitshalo zamandla zilayishwa ngamapayipi ahambisanayo, agcwele inqwaba yamasango, imbulunga, isheke, uvemvane namavalve ebhola.

Izitshalo zamandla enuzi zisebenza ngomgomo ofanayo womusi/ijubane eliphezulu. Umehluko oyinhloko ukuthi endaweni yamandla enuzi, isitimu sidalwa ukushisa okuvela enqubweni yokuqhekeka. Amavalvu ezitshalo zamandla enuzi afana nabazala babo abaphehlwa izinsalela, ngaphandle kozalo lwabo kanye nemfuneko eyengeziwe yokwethembeka okuphelele. Amavalvu enuzi enziwe abe sezingeni eliphezulu kakhulu, kanti imibhalo efanelekile neyokuhlola igcwalisa amakhulukhulu amakhasi.

UKUKHIQIZWA KWAMAFUTHA NEGASI
Imithombo kawoyela negesi kanye nezindawo zokukhiqiza kungabasebenzisi abasindayo bamavalvu, okuhlanganisa namavalvu amaningi esindayo. Nakuba izimfucumfucu zikawoyela ezikhafulela amakhulu amamitha emoyeni zingeke zisaba khona, isithombe sibonisa umfutho ongase ube khona kawoyela negesi engaphansi komhlaba. Yingakho amakhanda emithombo noma izihlahla zikaKhisimusi zibekwe phezulu entanjeni yepayipi elide lomthombo. Le mihlangano, nenhlanganisela yayo yamavalvu nokufakwa okukhethekile, iklanyelwe ukuphatha izingcindezi ezingaphezulu kuka-10,000 psi. Nakuba kungavamile ukutholakala emithonjeni embiwe emhlabeni kulezi zinsuku, izingcindezi eziphezulu kakhulu zivame ukutholakala emithonjeni ejulile yasogwini.

Idizayini yemishini ye-Wellhead imbozwa imininingwane ye-API efana ne-6A, Ukucaciswa Kwe-Wellhead kanye Nezisetshenziswa Zesihlahla sikaKhisimusi. Amavalvu ambozwe ku-6A aklanyelwe ukucindezela okuphezulu kakhulu kodwa amazinga okushisa anesizotha. Izihlahla eziningi zikaKhisimusi ziqukethe ama-valve esango kanye nama-valve embulunga akhethekile abizwa ngokuthi ama-chokes. Imiklinya isetshenziselwa ukulawula ukugeleza okuvela emthonjeni.

Ngaphezu kwama-wellheads ngokwawo, izinsiza eziningi ezihambisanayo zihlala endaweni kawoyela noma yegesi. Imishini yokucubungula ukwelapha uwoyela noma igesi ngaphambilini idinga amavalvu amaningi. Lawa ma-valve ngokuvamile ayinsimbi ye-carbon elinganiselwe kumakilasi aphansi.

Ngezinye izikhathi, uketshezi olugqwala kakhulu—i-hydrogen sulfide—luba khona emfudlaneni we-petroleum eluhlaza. Le nto, ebizwa nangokuthi igesi emuncu, ingaba yingozi. Ukwehlula izinselelo zegesi emuncu, izinto ezikhethekile noma amasu okucubungula izinto ngokuhambisana nencazelo ye-NACE International MR0175 kumele ilandelwe.

Imboni Yasolwandle
Amapayipi amapayipi emishini kawoyela yasogwini kanye nezindawo zokukhiqiza aqukethe inqwaba yamavalvu akhelwe emibhalweni eminingi ehlukene ukuze asingathe izinselelo eziningi zokulawula ukugeleza. Lezi zikhungo futhi ziqukethe izihibe zesistimu yokulawula ehlukahlukene kanye namadivayisi okusiza ukucindezela.

Ezindaweni zokukhiqiza uwoyela, inhliziyo ye-arterial iwuhlelo lwangempela lwamapayipi okubuyisela uwoyela noma igesi. Nakuba kungenaso sonke isikhathi endaweni yesikhulumi ngokwayo, izinhlelo eziningi zokukhiqiza zisebenzisa izihlahla zikaKhisimusi kanye nezinhlelo zamapayipi ezisebenza ekujuleni okungamamitha angu-10,000 noma ngaphezulu. Lesi sixhobo sokukhiqiza sakhelwe kumazinga amaningi aqondile e-American Petroleum Institute (API) futhi kukhonjwa ku-API Recommended Practices (RPs) embalwa.

Kumapulatifomu amaningi amakhulu kawoyela, izinqubo ezengeziwe zisetshenziswa oketshezini olungahluziwe oluvela esihlokweni somthombo. Lokhu kufaka phakathi ukuhlukanisa amanzi kuma-hydrocarbon kanye nokuhlukanisa igesi negesi yemvelo uketshezi emgudwini woketshezi. Lezi zinhlelo zamapayipi ezihlahla zangemva kukaKhisimusi zivame ukwakhelwa amakhodi epayipi e-American Society of Mechanical Engineers B31.3 ngamavalvu aklanywe ngokuhambisana nokucaciswa kwamavalvu e-API njenge-API 594, API 600, API 602, API 608 kanye ne-API 609.

Ezinye zalezi zinhlelo zingase futhi ziqukathe isango le-API 6D, ibhola namavalvu okuhlola. Njengoba noma yimaphi amapayipi epulatifomu noma umkhumbi wokubhoboza angaphakathi endaweni, izimfuneko eziqinile zokusebenzisa amavalvu e-API 6D kumapayipi azisebenzi. Nakuba izinhlobo eziningi zama-valve zisetshenziswa kulezi zinhlelo zamapayipi, uhlobo lwe-valve olukhethwayo yi-valve yebhola.

AMAPHAPHA
Nakuba amapayipi amaningi efihliwe ukuze angabonwa, ubukhona bawo buvame ukubonakala. Izimpawu ezincane ezisho “ipayipi likaphethiloli” zingenye yezinkomba ezisobala zokuba khona kwamapayipi okuthutha angaphansi komhlaba. Lawa mapayipi afakwe amavalvu amaningi abalulekile ngobude bawo. Amavalvu okuvala amapayipi ezimo eziphuthumayo atholakala ngezikhathi ezithile njengoba kuchazwe ngamazinga, amakhodi nemithetho. Lawa mavalvu asebenza ngenkonzo ebalulekile yokuhlukanisa ingxenye yepayipi uma ivuza noma lapho kudingeka ukulungiswa.

Okunye okuhlakazekile emzileni wamapayipi kukhona izinsiza lapho ulayini uvela phansi futhi kutholakala ukufinyelela kolayini. Lezi ziteshi ziyikhaya lempahla “yengulube” yokuqalisa, equkethe izinto ezifakwe emapayipini ukuze zihlole noma zihlanze ulayini. Lezi ziteshi zokwethula izingulube ngokuvamile ziqukethe ama-valve amaningana, kungaba yisango noma izinhlobo zebhola. Wonke ama-valve ohlelweni lwamapayipi kufanele abe yimbobo egcwele (ivuleke ngokugcwele) ukuvumela ukudlula kwezingulube.

Amapayipi nawo adinga amandla ukuze alwe nokungqubuzana kwepayipi nokugcina ukucindezela nokugeleza kolayini. I-Compressor noma iziteshi zokupompa ezibukeka njengezinguqulo ezincane zesitshalo senqubo ngaphandle kwemibhoshongo emide eqhekekile ziyasetshenziswa. Lezi ziteshi ziyikhaya lenqwaba yamavalvu esango, amabhola kanye namapayipi okuhlola.
Amapayipi ngokwawo aklanywe ngokuhambisana namazinga ahlukahlukene namakhodi, kuyilapho amapayipi amapayipi elandela i-API 6D Pipeline Valves.
Kukhona namapayipi amancane aphakela ezindlini nasezindaweni zezentengiselwano. Le migqa ihlinzeka ngamanzi negesi futhi igadwe ngamavalve wokuvala.
Omasipala abakhulu, ikakhulukazi engxenyeni esenyakatho ye-United States, bahlinzeka ngesitimu ngezimfuneko zokushisisa zamakhasimende athengisayo. Le migqa yokuhlinzeka ngesitimu ifakwe ama-valve ahlukahlukene okulawula nokulawula ukunikezwa kwesitimu. Nakuba uketshezi luyisitimu, izingcindezi namazinga okushisa aphansi kunalawo atholakala emshinini wokuphehla isitimu. Izinhlobonhlobo zezinhlobo zama-valve zisetshenziswa kule sevisi, nakuba i-valve yepulaki ehlonishwayo iseyinketho ethandwayo.

I-REFINERY KANYE NE-PETROCHEMICAL
Ama-valve okucwenga asebenza kakhulu ekusetshenzisweni kwamavalvu ezimbonini kunanoma iyiphi enye ingxenye yamavalvu. Izindawo zokuhlanza ziyikhaya lakho kokubili uketshezi olubolayo futhi kwezinye izimo, izinga lokushisa eliphezulu.
Lezi zici zinquma ukuthi ama-valve akhiwa kanjani ngokuhambisana nokucaciswa kwe-API ye-valve efana ne-API 600 (amavalvu esango), i-API 608 (amavalvu ebhola) kanye ne-API 594 (hlola amavalvu). Ngenxa yensizakalo enzima etholwa amaningi ala mavalvu, ngokuvamile kudingeka imali eyengeziwe yokugqwala. Lesi sibonelelo sibonakala ngokuqina okukhulu kwezindonga ezicaciswe kumadokhumenti omklamo we-API.

Cishe zonke izinhlobo zama-valve amakhulu zingatholakala ngobuningi endaweni yokuhluza evamile enkulu. Ivalvu yesango etholakala yonke indawo iseyinkosi yegquma nenani elikhulu labantu, kodwa ama-valve aphenduka ingxenye yekota athatha inani elikhulu lesabelo sawo semakethe. Imikhiqizo yekota eyenza ingene ngempumelelo kule mboni (eyake yabuswa yimikhiqizo yomugqa) ihlanganisa ukusebenza okuphezulu kwamavalvu ovemvane aphindwe kathathu kanye namavalvu ebhola ahlezi ngensimbi.

Isango elivamile, imbulunga kanye nama-valve okuhlola asatholakala en-masse, futhi ngenxa yobuqotho bomklamo wawo nomnotho wokukhiqiza, ngeke anyamalale noma nini maduzane.
Izilinganiso zokucindezela zamavalvu okuhluza zigijima i-gamut kusukela ku-Class 150 kuya ku-Class 1500, ne-Class 300 edume kakhulu.
Izinsimbi zekhabhoni ezingenalutho, njenge-grade WCB (cast) kanye ne-A-105 (forged) yizinto ezisetshenziswa kakhulu ezishiwo futhi ezisetshenziswa kumavalvu esevisi yokuhluza. Izinhlelo zokusebenza eziningi zenqubo yokucwenga zicindezela imikhawulo yokushisa ephezulu yezinsimbi zekhabhoni engenalutho, futhi ama-alloys okushisa aphezulu acacisiwe kulezi zinhlelo zokusebenza. Okudume kakhulu kulawa ama-chrome/moly steels afana no-1-1/4% Cr, 2-1/4% Cr, 5% Cr no-9% Cr. Izinsimbi ezingagqwali nama-alloys ane-nickel ephezulu nazo zisetshenziswa kwezinye izinqubo zokucwenga ezinokhahlo.

CHEMICAL
Imboni yamakhemikhali ingumsebenzisi omkhulu wamavalvu azo zonke izinhlobo nezinto zokwakha. Ukusuka ezitshalweni zeqoqo elincane kuya kuma-petrochemical complexes amakhulu atholakala e-Gulf Coast, ama-valve ayingxenye enkulu yezinqubo zamapayipi ezinqubo zamakhemikhali.

Izicelo eziningi ezinqubweni zamakhemikhali zingaphansi kwengcindezi kunezinqubo eziningi zokucwenga kanye nokukhiqizwa kwamandla. Izigaba zokucindezela ezidume kakhulu zamavalvu ezitshalo zamakhemikhali namapayipi amaClass 150 kanye nama-300. Izitshalo zamakhemikhali ziphinde zaba umshayeli omkhulu wokuthathwa kwesabelo semakethe lapho amavalvu ebhola ebambene khona namavalvu alayini eminyakeni engu-40 edlule. I-valve yebhola ehlala iqinile, nokuvalwa kwayo kokuvuza okuyiziro, ilingana kahle nezinhlelo eziningi zezitshalo zamakhemikhali. Usayizi ohlangene we-valve yebhola uyisici esithandwayo futhi.
Kusenezitshalo zamakhemikhali nezinqubo zezitshalo lapho amavalvu emigqa ekhethwayo. Kulezi zimo, ama-valve aklanywe nge-API 603 adumile, anezindonga ezincanyana nezisindo ezilula, ngokuvamile ayisango noma i-valve yembulunga yokuzikhethela. Ukulawula amanye amakhemikhali nakho kwenziwa ngempumelelo ngama-diaphragm noma ama-pinch valves.
Ngenxa yokugqwala kwamakhemikhali amaningi nezinqubo zokwenza amakhemikhali, ukukhethwa kwezinto ezibonakalayo kubalulekile. Izinto ze-defacto ziyizinga le-316/316L le-austenitic stainless steel. Le nto isebenza kahle ukulwa nokugqwala okuvela kuketshezi oluningi kwesinye isikhathi olubi.

Kwezinye izinhlelo zokusebenza ezonakalisayo, ukuvikelwa okwengeziwe kuyadingeka. Amanye amamaki aphezulu ensimbi engenasici ye-austenitic, i-317, i-347 ne-321 ivame ukukhethwa kulezi zimo. Amanye ama-alloys asetshenziswa ngezikhathi ezithile ukulawula uketshezi lwamakhemikhali ahlanganisa i-Monel, i-Alloy 20, i-Inconel kanye ne-17-4 PH.

UKUHLUKANISWA KWE-LNG NEGASI
Kokubili igesi yemvelo ewuketshezi (LNG) kanye nezinqubo ezidingekayo ukuze kuhlukaniswe igesi kuncike ekufakweni kwamapayipi okubanzi. Lezi zinhlelo zokusebenza zidinga ama-valve angasebenza emazingeni okushisa aphansi kakhulu e-cryogenic. Imboni ye-LNG, ekhula ngokushesha e-United States, ibheke ngokuqhubekayo ukuthuthukisa nokwenza ngcono inqubo yokuncibilika kwegesi. Kuze kube manje, amapayipi nama-valve asekhule kakhulu futhi izidingo zokucindezela ziye zaphakanyiswa.

Lesi simo sidinga ukuthi abakhiqizi bama-valve bathuthukise imiklamo yokuhlangabezana nemingcele eqinile. Ibhola le-quarter-turn namavalve ovemvane adumile ngesevisi ye-LNG, ne-316ss [insimbi engagqwali] into ethandwa kakhulu. I-ANSI Class 600 wuphahla olujwayelekile lwengcindezi yezinhlelo eziningi ze-LNG. Nakuba imikhiqizo yekota-turn iyizinhlobo zamavalvu ezidume kakhulu, isango, iglobhu kanye nama-valve okuhlola angatholakala nasezitshalweni.

Isevisi yokuhlukanisa igesi ihlanganisa ukuhlukanisa igesi ibe izici zayo eziyisisekelo. Isibonelo, izindlela zokuhlukanisa umoya zikhiqiza i-nitrogen, umoya-mpilo, i-helium namanye ama-trace gases. Isimo sokushisa esiphansi kakhulu senqubo sisho ukuthi ama-valve amaningi e-cryogenic ayadingeka.

Kokubili izitshalo zokuhlukanisa i-LNG negesi zinama-valve angamazinga okushisa aphansi okufanele ahlale esebenza kulezi zimo ze-cryogenic. Lokhu kusho ukuthi isistimu yokupakisha i-valve kufanele iphakanyiswe kude noketshezi olunezinga lokushisa eliphansi ngokusebenzisa igesi noma ikholomu yokujiya. Le kholomu yegesi ivimbela uketshezi ekwenzeni ibhola leqhwa elizungeze indawo yokupakisha, okungavimbela isiqu se-valve ukuba siphenduke noma sikhuphuke.

IZAKHIWO ZOKUTHENGISA
Izakhiwo zezentengiselwano zisizungezile kodwa ngaphandle uma silalelisisa njengoba zakhiwa, asinalo ulwazi oluncane ngobuningi bemithambo ewuketshezi efihlwe ezindongeni zazo zobumashi, ingilazi nensimbi.

Isici esivamile cishe kuwo wonke amabhilidi amanzi. Zonke lezi zakhiwo ziqukethe izinhlobonhlobo zezinhlelo zamapayipi ezithwala inhlanganisela eminingi ye-hydrogen/oxygen compound ngendlela yoketshezi oluphuzwayo, amanzi angcolile, amanzi ashisayo, amanzi ampunga nokuvikelwa komlilo.

Ngokombono wokusinda kwesakhiwo, izinhlelo zomlilo zibaluleke kakhulu. Ukuvikelwa komlilo ezakhiweni cishe kuphakelwa emhlabeni wonke futhi kugcwaliswe ngamanzi ahlanzekile. Ukuze izinhlelo zamanzi omlilo zisebenze kahle, kufanele zithembeke, zibe nokucindezela okwanele futhi zibekwe kalula kulo lonke isakhiwo. Lawa masistimu enzelwe ukuthi anikeze amandla ngokuzenzakalelayo esimweni somlilo.
Izakhiwo eziphakeme zidinga isevisi yokucindezela kwamanzi efanayo ezitezi ezingaphezulu njengoba ezitezi eziphansi ngakho amaphampu anengcindezi ephezulu kanye namapayipi kufanele asetshenziselwe ukukhuphula amanzi. Amasistimu amapayipi ngokuvamile ayi-Class 300 noma 600, kuya ngobude besakhiwo. Zonke izinhlobo zama-valve zisetshenziswa kulezi zicelo; kodwa-ke, amadizayini amavalvu kufanele agunyazwe i-Underwriters Laboratories noma i-Factory Mutual ngenkonzo eyinhloko yomlilo.

Amakilasi afanayo kanye nezinhlobo zama-valve asetshenziselwa ama-valve wenkonzo yomlilo asetshenziselwa ukusatshalaliswa kwamanzi aphuzwayo, nakuba inqubo yokugunyaza ingekho eqinile.
Amasistimu omoya wezohwebo atholakala ezakhiweni ezinkulu zebhizinisi njengezakhiwo zamahhovisi, amahhotela nezibhedlela ngokuvamile afakwa endaweni eyodwa. Zineyunithi yokupholisa enkulu noma ibhoyili yokupholisa noma ukushisisa uketshezi olusetshenziselwa ukudlulisa amakhaza noma izinga lokushisa eliphezulu. Lezi zinhlelo ngokuvamile kufanele zibambe iziqandisi ezifana ne-R-134a, i-hydro-fluorocarbon, noma esimweni samasistimu amakhulu okushisisa, isitimu. Ngenxa yosayizi ohlangene wovemvane namavalvu ebhola, lezi zinhlobo sezidumile kumasistimu wokupholisa ama-HVAC.

Ngasohlangothini lwesitimu, amanye ama-valve e-quarter-turn angenele ukusetshenziswa, nokho onjiniyela abaningi bamapayipi basathembele emasangweni alayini kanye namavalvu eglobhu, ikakhulukazi uma ukubhobhoza kudinga iziphetho ze-butt-weld. Kulokhu kufakwa kwesitimu esimaphakathi, insimbi ithathe indawo yensimbi ngenxa yokushisela kwensimbi.

Ezinye izinhlelo zokufudumeza zisebenzisa amanzi ashisayo esikhundleni sesitimu njengoketshezi lokudlulisa. Lezi zinhlelo zikhonzwa kahle ngama-valve ethusi noma ensimbi. Ibhola le-quarter-turn resilient-seated-seated kanye nama-butterfly valves athandwa kakhulu, nakuba eminye imiklamo eqondile isasetshenziswa.

ISIPHETHO
Nakuba ubufakazi bezicelo zevalvu okukhulunywe ngabo kulesi sihloko bungase bungabonakali phakathi nohambo oluya e-Starbucks noma endlini kagogo, amanye ama-valve abaluleke kakhulu ahlala eseduze. Kukhona nama-valve enjinini yemoto esetshenziswa ukufika kulezo zindawo njengalawo aku-carburetor alawula ukugeleza kukaphethiloli enjinini nalawo asenjinini alawula ukugeleza kukaphethroli kumapiston aphinde aphume. Futhi uma lawo mavalvu engasondeli ngokwanele ekuphileni kwethu kwansuku zonke, cabangela iqiniso lokuthi izinhliziyo zethu zishaya njalo ngemishini emine ebalulekile yokulawula ukugeleza.

Lesi ngesinye isibonelo seqiniso lokuthi: ama-valve akhona yonke indawo ngempela. VM
Ingxenye II yalesi sihloko ihlanganisa izimboni ezengeziwe lapho kusetshenziswa ama-valve. Yiya ku-www.valvemagazine.com ukuze ufunde mayelana ne-pulp nephepha, izinhlelo zokusebenza zasolwandle, amadamu namandla kagesi ophehlwa ngamanzi, ilanga, insimbi nensimbi, i-aerospace, i-geothermal, kanye nokuphiswa kwemisebenzi yezandla kanye ne-distilling.

UGREG JOHNSON ungumongameli we-United Valve (www.unitedvalve.com) e-Houston. Ungumhleli onikelayo ku-VALVE Magazine, usihlalo odlule woMkhandlu Wokulungisa Ama-Valve kanye nelungu lamanje lebhodi le-VRC. Uphinde asebenze eKomidini Lezemfundo Nokuqeqesha le-VMA, uyisekela likasihlalo weKomidi Lezokuxhumana le-VMA futhi useke waba ngumongameli we-Manufacturers Standardization Society.