Apho Kusetyenziswa Iivalvu: Kuyo Yonke Indawo!

08 Novemba 2017 Ibhalwe nguGreg Johnson

Iivalvu zingafumaneka naphi na namhlanje: emakhayeni ethu, phantsi kwesitalato, kwizakhiwo zorhwebo nakwiindawo ezininzi ngaphakathi kwizityalo zamandla namanzi, kwiifektri zamaphepha, kwiindawo zokucocisa, kwizityalo zeekhemikhali nakwezinye izibonelelo zoshishino neziseko.
Ishishini leevalvu libanzi ngokwenene, kwaye amacandelo ahluka ukusuka ekusasazweni kwamanzi ukuya kumandla enyukliya ukuya kwi-oyile negesi ephezulu kunye nesezantsi. Ngalinye lala mashishini abasebenzisi bokugqibela lisebenzisa iintlobo ezithile ezisisiseko zeevalvu; nangona kunjalo, iinkcukacha zokwakha kunye nezixhobo zihlala zahlukile kakhulu. Nantsi isampuli:

IMISEBENZI YAMANZI
Kwihlabathi lokusasazwa kwamanzi, uxinzelelo luhlala luphantsi kwaye amaqondo obushushu ahlala ekhona. Ezo nkcukacha zimbini zokusetyenziswa zivumela inani lezinto zoyilo lweevalvu ezingafumanekiyo kwizixhobo ezinzima kakhulu ezifana neevalvu zomphunga ezinobushushu obuphezulu. Ubushushu obuhlala bukhona benkonzo yamanzi buvumela ukusetyenziswa kwee-elastomers kunye nezitywino zerabha ezingafanelekiyo kwenye indawo. Ezi zinto zithambileyo zivumela iivalvu zamanzi ukuba zixhotyiswe ukuze zivale kakuhle iidriphu.

Enye into eqwalaselwayo kwiivalvu zenkonzo yamanzi kukukhetha izinto zokwakha. Iintsimbi zesamente neze-ductile zisetyenziswa kakhulu kwiinkqubo zamanzi, ingakumbi imigca emikhulu yobubanzi bangaphandle. Imigca emincinci kakhulu ingaphathwa kakuhle ngezinto zeevalvu zebronze.

Iingcinezelo ezibonwa ziivalvu ezininzi zemisebenzi yamanzi zihlala zingaphantsi kwe-200 psi. Oku kuthetha ukuba akufuneki uyilo olunoxinzelelo oluphezulu oluneendonga ezijiyileyo. Oko kuthethiweyo, kukho iimeko apho iivalvu zamanzi zakhiwe ukuze zikwazi ukusingatha uxinzelelo oluphezulu, olufikelela kwi-300 psi. Ezi zicelo zihlala zikwimijelo yamanzi emide ekufutshane nomthombo woxinzelelo. Ngamanye amaxesha iivalvu zamanzi ezinoxinzelelo oluphezulu zikwafumaneka kwiindawo ezinoxinzelelo oluphezulu kwidama elide.

I-American Water Works Association (AWWA) ikhuphe iinkcukacha ezigubungela iintlobo ezahlukeneyo zeevalvu kunye nee-actuator ezisetyenziswa kwimisebenzi yamanzi.

AMANZI Amdaka
Icala elingasemva lamanzi acocekileyo okusela angena kwiziko okanye kwisakhiwo ngamanzi amdaka okanye amdaka aphumayo. Le migca iqokelela lonke ulwelo lwenkunkuma kunye nezinto eziqinileyo ize izikhokelele kwisityalo sokucoca amanzi amdaka. Ezi zityalo zonyango zinemibhobho emininzi kunye neevalvu ezinoxinzelelo oluphantsi ukuze zenze "umsebenzi wazo ongcolileyo." Iimfuno zeevalvu zamanzi amdaka kwiimeko ezininzi zilula kakhulu kuneemfuno zenkonzo yamanzi acocekileyo. Iivalvu zesango lesinyithi kunye neetshekhi zezona zikhethwa kakhulu kolu hlobo lwenkonzo. Iivalvu ezisemgangathweni kule nkonzo zakhiwe ngokweemfuno ze-AWWA.

ISHISHINI LAMANDLA
Uninzi lwamandla ombane aveliswa eMelika enziwa kwizityalo zomphunga kusetyenziswa iifosili kunye neeturbines ezikhawulezayo. Ukuhluba umva isigqubuthelo sesityalo samandla sanamhlanje kuya kunika umbono weenkqubo zombhobho ezinoxinzelelo oluphezulu, ezishushu kakhulu. Le migca iphambili yeyona ibalulekileyo kwinkqubo yokuvelisa umbane ngomphunga.

Iivalvu zesango zihlala zilukhetho oluphambili kwiindlela zokuvula/ukucima isityalo samandla, nangona zikwafumaneka iivalvu zeglobe ze-Y-pattern. Iivalvu zebhola ezisebenza kakuhle nezinenkonzo ebalulekileyo ziyathandwa ngabayili bezityalo zamandla kwaye ziyangena kweli hlabathi elalikade lilawulwa ziivalvu ezithe tye.

I-Metallurgy ibalulekile kwiivalvu kwizicelo zamandla, ingakumbi ezo zisebenza kuluhlu lokusebenza olubalulekileyo okanye olubaluleke kakhulu loxinzelelo kunye nobushushu. I-F91, i-F92, i-C12A, kunye nee-alloys ezininzi ze-Inconel kunye ne-stainless-steel zisetyenziswa kakhulu kwizityalo zamandla zanamhlanje. Iiklasi zoxinzelelo ziquka i-1500, i-2500 kwaye kwezinye iimeko i-4500. Uhlobo lokuguqula izityalo zamandla ezikumgangatho ophezulu (ezo zisebenza kuphela xa kufuneka) lukwabeka uxinzelelo olukhulu kwiivalvu kunye nemibhobho, ifuna uyilo oluqinileyo lokujongana nomxube ogqithisileyo wokujikeleza, ubushushu kunye noxinzelelo.
Ukongeza kwi-valve ephambili yomphunga, izityalo zamandla zigcwele imibhobho encedisayo, ezaliswe zii-gate, iglobe, itshekhi, ibhabhathane kunye nee-ball valves ezininzi.

Izityalo zamandla enyukliya zisebenza ngomgaqo ofanayo womphunga/i-turbine enesantya esiphezulu. Umahluko ophambili kukuba kwisityalo samandla enyukliya, umphunga wenziwa bubushushu obuvela kwinkqubo yokuqhekeka. Iivalvu zesityalo samandla enyukliya zifana nezalamane zazo ezisebenzisa amafutha efosili, ngaphandle kwemvelaphi yazo kunye nemfuneko eyongezelelweyo yokuthembeka ngokupheleleyo. Iivalvu zenyukliya zenziwe ngemigangatho ephezulu kakhulu, kwaye amaxwebhu afanelekileyo nawokuhlolwa azalisa amakhulu amaphepha.

IMVELISO YEOYILE NEGESI
Imithombo yeoyile negesi kunye neendawo zokuvelisa zisetyenziswa kakhulu ziivalvu, kuquka iivalvu ezininzi ezinzima. Nangona ii-oyile ezikhupha amanzi aphumayo emoyeni zingasabonakali, umfanekiso ubonisa uxinzelelo olunokubakho lweoyile negesi engaphantsi komhlaba. Yiyo loo nto iintloko zemithombo okanye imithi yeKrismesi zibekwe phezulu kwintambo ende yombhobho womthombo. Ezi ndibano, kunye nokudibanisa kwazo iivalvu kunye nezixhobo ezikhethekileyo, zenzelwe ukujongana noxinzelelo olungaphezulu kwe-10,000 psi. Nangona zinqabile ukufumaneka kwimithombo embiwe emhlabeni kule mihla, uxinzelelo oluphezulu kakhulu luhlala lufumaneka kwimithombo enzulu yonxweme.

Uyilo lwezixhobo zeWellhead lugutyungelwe ziinkcukacha ze-API ezifana ne-6A, Iinkcukacha zeWellhead kunye nezixhobo zomthi weKrismesi. Iivalvu ezigqunywe kwi-6A zenzelwe uxinzelelo oluphezulu kakhulu kodwa amaqondo obushushu aphantsi. Uninzi lwemithi yeKrismesi luqulathe iivalvu zesango kunye neevalvu ezikhethekileyo zeglobe ezibizwa ngokuba zii-chokes. Ii-chokes zisetyenziselwa ukulawula ukuhamba kwamanzi ukusuka emthonjeni.

Ukongeza kwiintloko zemithombo ngokwazo, ezinye izakhiwo ezincedisayo zigcwele intsimi yeoyile okanye yegesi. Izixhobo zokucubungula ioyile okanye igesi kwangaphambili zifuna iivalvu ezininzi. Ezi valve zihlala zilinganiswa ngentsimbi yekhabhoni kwiiklasi eziphantsi.

Ngamanye amaxesha, ulwelo oludlaka kakhulu—i-hydrogen sulfide—lukho kumjelo wepetroleum ongavuthwanga. Le nto, ekwabizwa ngokuba yigesi emuncu, inokubulala. Ukuze koyiswe imingeni yegesi emuncu, kufuneka kulandelwe izinto ezikhethekileyo okanye iindlela zokucubungula izinto ngokwemigaqo ye-NACE International MR0175.

ISHISHINI LASE-OFFSHORE
Iinkqubo zokufaka imibhobho kwiindawo zokubeka ioyile ezikude nolwandle kunye neendawo zokuvelisa ziqulathe iivalvu ezininzi ezakhiwe ngokweemfuno ezahlukeneyo ukujongana nemingeni eyahlukeneyo yokulawula ukuhamba kwamanzi. Ezi zixhobo zikwanazo neendlela ezahlukeneyo zokulawula kunye nezixhobo zokunciphisa uxinzelelo.

Kwizixhobo zokuvelisa ioyile, intliziyo yemithambo yegazi yeyona nkqubo yokubuyisela ioyile okanye igesi. Nangona ingekho rhoqo eqongeni ngokwalo, iinkqubo ezininzi zemveliso zisebenzisa imithi yeKrismesi kunye neenkqubo zemibhobho ezisebenza kubunzulu obungafikelelekiyo beenyawo ezili-10,000 nangaphezulu. Ezi zixhobo zemveliso zakhiwe ngokwemigangatho emininzi echanekileyo ye-American Petroleum Institute (API) kwaye zikhankanywa kwiindlela ezininzi ezicetyiswayo ze-API (RPs).

Kwiiplatifomu ezininzi zeoyile ezinkulu, iinkqubo ezongezelelweyo zisetyenziswa kulwelo olungavuthwanga oluvela kwintloko yomthombo. Ezi ziquka ukwahlula amanzi kwiihydrocarbons kunye nokwahlula ulwelo lwegesi kunye negesi yendalo kumjelo wolwelo. Ezi nkqubo zemibhobho emva komthi weKrismesi ngokubanzi zakhiwe ngokweekhowudi zemibhobho ze-American Society of Mechanical Engineers B31.3 ezineevalvu eziyilwe ngokuhambelana neenkcukacha zevalvu ze-API ezifana ne-API 594, API 600, API 602, API 608 kunye ne-API 609.

Ezinye zezi nkqubo zinokuba neevalvu zesango le-API 6D, ibhola kunye ne-check. Ekubeni nayiphi na imibhobho eqongeni okanye kwinqanawa yokugrumba ingaphakathi kwiziko, iimfuno ezingqongqo zokusebenzisa iivalvu ze-API 6D kwimibhobho azisebenzi. Nangona kusetyenziswa iintlobo ezininzi zeevalvu kwezi nkqubo zemibhobho, uhlobo lwevalvu olukhethwayo yivalvu yebhola.

IMIPHAYIPHI
Nangona uninzi lwemibhobho ingabonakali, ubukho bayo buhlala bubonakala. Imiqondiso emincinci ethi "ipayipi yepetroli" yenye yeempawu ezicacileyo zokuba kukho imibhobho yokuthutha engaphantsi komhlaba. Le mibhobho ixhotyiswe ngeevalvu ezininzi ezibalulekileyo ubude bayo bonke. Iivalvu zokuvala imibhobho ngexesha likaxakeka zifunyanwa ngamaxesha athile njengoko kuchaziwe yimigangatho, iikhowudi kunye nemithetho. Ezi valve zisebenza njengenkonzo ebalulekileyo yokwahlula icandelo lombhobho xa kukho ukuvuza okanye xa kufuneka ukulungiswa.

Kwakhona kukwakho neendawo ezisasazekileyo kwindlela yombhobho apho umgca uphuma khona emhlabeni kwaye kukwakho nokufikelela kumgca. Ezi zikhululo zikhaya lezixhobo zokuqalisa "iihagu", eziquka izixhobo ezifakwe kwimibhobho nokuba kukuhlola okanye ukucoca umgca. Ezi zikhululo zokuqalisa iihagu zihlala ziqulathe iivalvu ezininzi, nokuba ziintlobo zesango okanye zebhola. Zonke iivalvu ezikwinkqubo yombhobho kufuneka zibe zizibuko ezigcweleyo (zivuleke ngokupheleleyo) ukuze zivumele ukuhamba kweehagu.

Iipayipi zikwafuna amandla ukulwa nokungqubana kwepayipi nokugcina uxinzelelo nokuhamba komgca. Kusetyenziswa i-compressor okanye izitishi zokumpompa ezibonakala ngathi ziinguqulelo ezincinci zesityalo sokucwangcisa ngaphandle kweenqaba ezinde zokuqhekeka. Ezi zitishi zilikhaya leevalvu ezininzi zesango, ibhola kunye nepayipi yokujonga.
Iipayipi ngokwazo ziyilwe ngokwemigangatho kunye neekhowudi ezahlukeneyo, ngelixa iivalvu zepayipi zilandela iivalvu zePipeline ze-API 6D.
Kukwakho nemibhobho emincinci efikelela ezindlwini nakwizakhiwo zorhwebo. Le migca ibonelela ngamanzi negesi kwaye ikhuselwe ziivalvu ezivaliweyo.
Oomasipala abakhulu, ingakumbi kumantla e-United States, babonelela ngomphunga kwiimfuno zokufudumeza zabathengi bezorhwebo. Le migca yokubonelela ngomphunga ixhotyiswe ngeevalvu ezahlukeneyo zokulawula nokulawula unikezelo lomphunga. Nangona ulwelo lungumphunga, uxinzelelo kunye namaqondo obushushu aphantsi kunalawo afumaneka ekuveliseni umphunga kwizityalo zamandla. Iindidi ezahlukeneyo zeevalvu zisetyenziswa kule nkonzo, nangona ivalvu yeplagi ehloniphekileyo iselukhetho oludumileyo.

INDAWO YOKUHLANZA NOKUTSHINTSHA I-PETROCHEMICAL
Iivalvu zokucoca zisetyenziswa kakhulu kwiivalvu zoshishino kunakwezinye iindawo zeevalvu. Iindawo zokucoca ziindawo ezinazo zombini ulwelo olubolayo kwaye kwezinye iimeko, kukho amaqondo obushushu aphezulu.
Ezi zinto zilawula indlela iivalvu ezakhiwa ngayo ngokweemfuno zoyilo lweevalvu ze-API ezifana ne-API 600 (iivalvu zesango), i-API 608 (iivalvu zebhola) kunye ne-API 594 (jonga iivalvu). Ngenxa yenkonzo enzima efunyanwa zezi valve ezininzi, kufuneka isibonelelo esongezelelweyo sokugqwala. Esi sibonelelo sibonakala ngobukhulu obukhulu beendonga ezichazwe kumaxwebhu oyilo lwe-API.

Phantse zonke iintlobo zeevalvu ezinkulu zinokufumaneka ngobuninzi kwindawo yokuhluza eqhelekileyo enkulu. Ivalvu yesango exhaphakileyo isengukumkani wentaba enabemi abaninzi, kodwa iivalvu zekota-turn zithatha inani elikhulu lesabelo sazo semarike. Iimveliso zekota-turn ezenza impumelelo kweli shishini (elalikade lilawulwa ziimveliso ezithe tyaba) ziquka iivalvu zebhabhathane ezintathu ezisebenza kakuhle kunye neevalvu zebhola ezihlala ngentsimbi.

Isango eliqhelekileyo, iglobhu kunye neevalvu zokujonga zisafumaneka ngobuninzi, kwaye ngenxa yobuchule boyilo lwazo kunye noqoqosho lwemveliso, aziyi kunyamalala kungekudala.
Uvavanyo loxinzelelo lweevalvu zokucoca luqala kwiKlasi ye-150 ukuya kwiKlasi ye-1500, kwaye iKlasi ye-300 yeyona idumileyo.
Iintsimbi zekhabhoni ezingenanto, ezifana ne-grade WCB (cast) kunye ne-A-105 (forged) zezona zinto zidumileyo nezisetyenziswa kwiivalvu zenkonzo yokucocisa. Uninzi lweenkqubo zokucocisa lutyhala imida yobushushu ephezulu yeentsimbi zekhabhoni ezingenanto, kwaye ii-alloys zobushushu obuphezulu zichaziwe kwezi zicelo. Ezona zidumileyo kwezi ziintsimbi ze-chrome/moly ezifana ne-1-1/4% Cr, 2-1/4% Cr, 5% Cr kunye ne-9% Cr. Iintsimbi ezingenasici kunye nee-alloys ze-nickel eziphezulu nazo zisetyenziswa kwiinkqubo zokucocisa ezinzima kakhulu.

IKHEMIKALI
Ishishini leekhemikhali lisebenzisa kakhulu iivalvu zazo zonke iintlobo kunye nezinto. Ukususela kwizityalo ezincinci ukuya kwiicomplex ezinkulu zepetrochemical ezifumaneka kwiGulf Coast, iivalvu ziyinxalenye enkulu yeenkqubo zemibhobho yenkqubo yeekhemikhali.

Uninzi lwezicelo kwiinkqubo zeekhemikhali ziphantsi kuxinzelelo kuneenkqubo ezininzi zokucoca kunye nokuveliswa kombane. Iindidi zoxinzelelo ezidumileyo zeevalvu zezityalo zeekhemikhali kunye nemibhobho ziiKlasi 150 kunye ne-300. Izityalo zeekhemikhali nazo ziye zaba ngumqhubi omkhulu wokuthathwa kwesabelo semarike iivalvu zebhola eziye zalwa neevalvu ezithe ngqo kwiminyaka engama-40 edlulileyo. Ivalvu yebhola ehlala iqinile, ene-zero-leakage shutoff yayo, ifanelekile kwiizicelo ezininzi zezityalo zeekhemikhali. Ubungakanani obuncinci bevalvu yebhola luphawu oludumileyo.
Kusekho izityalo zeekhemikhali kunye neenkqubo zezityalo apho kukhethwa khona iivalvu ezithe tyaba. Kule meko, iivalvu ezidumileyo ze-API 603, ezineendonga ezincinci kunye nobunzima obulula, zihlala ziyivalvu yesango okanye yeglobe ekhethwayo. Ulawulo lwezinye iikhemikhali lukwafezekiswa ngempumelelo ngeevalvu ze-diaphragm okanye ze-pinch.
Ngenxa yokuba iikhemikhali ezininzi kunye neenkqubo zokwenza iikhemikhali ziyabola, ukukhetha izinto kubalulekile. Izinto ezisetyenzisiweyo ziyi-316/316L yentsimbi engagqwaliyo ye-austenitic. Ezi zinto zisebenza kakuhle ukulwa nokubola okuvela kwiintlobo ngeentlobo zezinye izinto ezinobungozi ngamanye amaxesha.

Kwezinye iindlela eziqinileyo zokubola, kufuneka ukhuseleko olungakumbi. Ezinye iindlela eziphezulu zokusebenza kwentsimbi engagqwaliyo ye-austenitic, ezifana ne-317, 347 kunye ne-321 zihlala zikhethwa kwezi meko. Ezinye ii-alloys ezisetyenziswa ngamaxesha athile ukulawula ulwelo lweekhemikhali ziquka iMonel, iAlloy 20, iInconel kunye ne-17-4 PH.

UKWAHLUKANISWA KWE-LNG NE-GAS
Zombini igesi yendalo engamanzi (i-LNG) kunye neenkqubo ezifunekayo zokwahlulwa kwegesi zixhomekeke kwimibhobho emikhulu. Ezi zicelo zifuna iivalvu ezinokusebenza kumaqondo obushushu aphantsi kakhulu. Ishishini le-LNG, elikhula ngokukhawuleza eMelika, lihlala lijonge ukuphucula nokuphucula inkqubo yokunyibilika kwegesi. Ngenxa yoku, imibhobho kunye neevalvu ziye zaba nkulu kakhulu kwaye iimfuno zoxinzelelo ziphakanyisiwe.

Le meko ifune ukuba abavelisi beevalvu baphuhlise uyilo ukuze bahlangabezane neeparameter eziqinileyo. Iivalvu zebhola ezijika ikota kunye neebhabhathane zithandwa kakhulu kwinkonzo ye-LNG, kwaye i-316ss [intsimbi engatyiwayo] yeyona nto idumileyo. I-ANSI Class 600 sisilingi soxinzelelo esiqhelekileyo kwiisicelo ezininzi ze-LNG. Nangona iimveliso zekota ezijika ikota zezona ntlobo zidumileyo zeevalvu, ii-gate, i-globe kunye neevalvu zokujonga zinokufumaneka nakwizityalo.

Inkonzo yokwahlula igesi ibandakanya ukwahlula igesi ibe zizinto zayo ezisisiseko. Umzekelo, iindlela zokwahlula umoya zivelisa i-nitrogen, i-oxygen, i-helium kunye nezinye iigesi ezilandelelanayo. Uhlobo oluphantsi kakhulu lobushushu benkqubo luthetha ukuba kufuneka iivalvu ezininzi ze-cryogenic.

Zombini izityalo ze-LNG kunye nezokwahlulahlula igesi zinezivali zobushushu obuphantsi ekufuneka zihlale zisebenza kwezi meko zi-cryogenic. Oku kuthetha ukuba inkqubo yokupakisha iivali kufuneka iphakanyiswe kude nolwelo lobushushu obuphantsi ngokusebenzisa igesi okanye ikholamu yokufutha. Le kholamu yegesi ithintela ulwelo ekubeni lwenze ibhola yomkhenkce ejikeleze indawo yokupakisha, nto leyo eya kuthintela isiqu sevali ukuba singajiki okanye sinyuke.

Izakhiwo zorhwebo
Izakhiwo zorhwebo zisijikelezile kodwa ngaphandle kokuba sinikele ingqalelo engakumbi njengoko zakhiwa, asinalo ulwazi oluninzi malunga nemithambo emininzi yolwelo efihliweyo kwiindonga zazo ezenziwe ngomthi, iglasi kunye nesinyithi.

Into eqhelekileyo phantse kuzo zonke izakhiwo ngamanzi. Zonke ezi zakhiwo ziqulathe iintlobo ngeentlobo zeenkqubo zokufaka imibhobho ezithwala indibaniselwano emininzi ye-hydrogen/oxygen compound ngendlela yolwelo oluselwayo, amanzi amdaka, amanzi ashushu, amanzi angwevu kunye nokhuseleko lomlilo.

Ngokwembono yokusinda kwesakhiwo, iinkqubo zomlilo zibaluleke kakhulu. Ukhuseleko lomlilo kwizakhiwo lufumaneka phantse kuwo wonke umhlaba kwaye luzaliswe ngamanzi acocekileyo. Ukuze iinkqubo zamanzi omlilo zisebenze kakuhle, kufuneka zithembeke, zibe noxinzelelo olwaneleyo kwaye zibekwe kwindawo efanelekileyo kuyo yonke isakhiwo. Ezi nkqubo zenzelwe ukuba zisebenze ngokuzenzekelayo xa kukho umlilo.
Izakhiwo eziphakamileyo zifuna inkonzo efanayo yoxinzelelo lwamanzi kumgangatho ophezulu njengemigangatho esezantsi ngoko ke kufuneka kusetyenziswe iimpompo zoxinzelelo oluphezulu kunye nemibhobho ukuze amanzi anyuke. Iinkqubo zombhobho zihlala ziyiKlasi 300 okanye 600, kuxhomekeke kubude besakhiwo. Zonke iintlobo zeevalvu ziyasetyenziswa kwezi zicelo; nangona kunjalo, uyilo lweevalvu kufuneka luvunywe yi-Underwriters Laboratories okanye iFactory Mutual yenkonzo ephambili yomlilo.

Iindidi ezifanayo kunye neentlobo zeevalvu ezisetyenziselwa iivalvu zenkonzo yomlilo zisetyenziselwa ukusasazwa kwamanzi okusela, nangona inkqubo yokuvunywa ingekho ngqongqo kangako.
Iinkqubo zomoya opholileyo zorhwebo ezifumaneka kwizakhiwo ezinkulu zoshishino ezifana nezakhiwo zeeofisi, iihotele kunye nezibhedlele zihlala ziphakathi. Zineyunithi enkulu yokupholisa okanye ibhoyila yokupholisa okanye yokufudumeza ulwelo olusetyenziselwa ukuhambisa ubushushu obubandayo okanye obuphezulu. Ezi nkqubo zihlala zifanele ziphathe iifriji ezifana ne-R-134a, i-hydro-fluorocarbon, okanye kwimeko yeenkqubo zokufudumeza ezinkulu, umphunga. Ngenxa yobukhulu obuncinci beevalvu zebhabhathane kunye neebhola, ezi ntlobo ziye zathandwa kwiinkqubo zokupholisa ze-HVAC.

Kwicala lomphunga, ezinye iivalvu ezijika ikota ziye zangena, kodwa uninzi lweenjineli zemibhobho zisaxhomekeke kwiivalvu zesango elithe tyaba kunye neeglobe, ingakumbi ukuba imibhobho ifuna iziphelo ze-butt-weld. Kwezi zicelo zomphunga ziphakathi, intsimbi ithathe indawo yentsimbi ephosiweyo ngenxa yokukwazi ukuwelda kwentsimbi.

Ezinye iinkqubo zokufudumeza zisebenzisa amanzi ashushu endaweni yomphunga njengolwelo lokudlulisa. Ezi nkqubo zikhonzwa kakuhle ziivalvu zebronze okanye zentsimbi. Iivalvu zebhola kunye neevalvu zebhabhathane ezihlala ziqinileyo ezinekota zithandwa kakhulu, nangona ezinye iindlela zoyilo ezithe tye zisasetyenziswa.

ISIPHELO
Nangona ubungqina bokusetyenziswa kweevalvu ezikhankanyiweyo kweli nqaku busenokungabonakali ngexesha lohambo oluya eStarbucks okanye endlwini kamakhulu, ezinye iivalvu ezibalulekileyo zihlala zikufutshane. Kukho neevalvu kwinjini yemoto ezisetyenziselwa ukufikelela kwiindawo ezifana nezo zikwi-carburetor ezilawula ukuhamba kwepetroli kwinjini kunye nezo zikwinjini ezilawula ukuhamba kwepetroli kwiipistons zize ziphume kwakhona. Kwaye ukuba ezo valve azisondelanga ngokwaneleyo kubomi bethu bemihla ngemihla, cinga ngenyani yokuba iintliziyo zethu zibetha rhoqo ngezixhobo ezine ezibalulekileyo zokulawula ukuhamba kwamanzi.

Lo ngomnye umzekelo wenyani yokuba: iivalvu zikho kuyo yonke indawo.
Inxalenye yesiBini yale nqaku igubungela amashishini ongezelelweyo apho kusetyenziswa khona iivalvu. Yiya ku-www.valvemagazine.com ukuze ufunde ngepulp nephepha, usetyenziso lwaselwandle, amadama kunye namandla ombane wamanzi, ilanga, isinyithi kunye nentsimbi, i-aerospace, i-geothermal, kunye nokwenza ubhiya kunye nokuhluza izinto zobugcisa.

UGREG JOHNSON ngumongameli we-United Valve (www.unitedvalve.com) eHouston. Ungumhleli oncedisayo kwi-VALVE Magazine, owayengusihlalo weBhunga loLungiso lweeValve kwaye ulilungu lebhodi ye-VRC ngoku. Ukwasebenza kwiKomiti yeMfundo noQeqesho ye-VMA, ungusekela-sihlalo weKomiti yoNxibelelwano ye-VMA kwaye wayengumongameli we-Manufacturers Standardization Society.