Kumene Ma Valves Amagwiritsidwa Ntchito: Kulikonse!

08 Novembala 2017 Yolembedwa ndi Greg Johnson

Ma valve amapezeka kulikonse masiku ano: m'nyumba zathu, pansi pa msewu, m'nyumba zamalonda komanso m'malo ambirimbiri mkati mwa mafakitale amagetsi ndi madzi, mafakitale a mapepala, mafakitale oyeretsera, mafakitale a mankhwala ndi malo ena opangira mafakitale ndi zomangamanga.
Makampani opanga ma valve ndi otakata kwambiri, ndipo magawo amasiyana kuyambira kugawa madzi mpaka mphamvu ya nyukiliya mpaka mafuta ndi gasi akumtunda komanso akumunsi. Makampani aliwonse ogwiritsa ntchito ma valve amagwiritsa ntchito mitundu yoyambira ya ma valve; komabe, tsatanetsatane wa kapangidwe ndi zipangizo nthawi zambiri zimakhala zosiyana kwambiri. Nayi zitsanzo:

NTCHITO ZA MADZI
Mu dziko la kugawa madzi, kupanikizika nthawi zambiri kumakhala kotsika ndipo kutentha kumakhala kozungulira. Mfundo ziwirizi zimalola zinthu zingapo zopangira ma valve zomwe sizingapezeke pazida zovuta kwambiri monga ma valve a nthunzi otentha kwambiri. Kutentha kwa madzi komwe kumagwiritsidwa ntchito kumalola kugwiritsa ntchito ma elastomer ndi zisindikizo za rabara zomwe sizingagwiritsidwe ntchito kwina kulikonse. Zipangizo zofewa izi zimathandiza kuti ma valve amadzi akhale okonzeka kutseka madontho mwamphamvu.

Chinthu china chomwe muyenera kuganizira mu ma valve ogwiritsira ntchito madzi ndi kusankha zipangizo zomangira. Zitsulo zotayidwa ndi zotayidwa zimagwiritsidwa ntchito kwambiri m'madzi, makamaka mizere ikuluikulu yakunja. Mizere yaying'ono kwambiri imatha kuyendetsedwa bwino ndi zipangizo za bronze valve.

Kupanikizika komwe ma valve ambiri amawona nthawi zambiri kumakhala kochepera 200 psi. Izi zikutanthauza kuti mapangidwe okhuthala okhala ndi makoma olimba safunikira. Komabe, pali nthawi zina pomwe ma valve amadzi amamangidwa kuti azitha kuthana ndi kupsinjika kwakukulu, mpaka pafupifupi 300 psi. Kugwiritsa ntchito kumeneku nthawi zambiri kumachitika pamitsinje yayitali pafupi ndi komwe kumachokera kupanikizika. Nthawi zina ma valve amadzi okhuthala kwambiri amapezekanso pamalo opanikizika kwambiri m'damu lalitali.

Bungwe la American Water Works Association (AWWA) lapereka malangizo okhudza mitundu yosiyanasiyana ya ma valve ndi ma actuator omwe amagwiritsidwa ntchito pa ntchito zamadzi.

Madzi Otayira
Mbali ina ya madzi abwino oti atuluke kupita ku malo kapena nyumba ndi madzi otayira kapena zimbudzi. Mizere iyi imasonkhanitsa zinyalala zonse ndi zinthu zolimba ndikuzitsogolera ku malo oyeretsera zimbudzi. Malo oyeretsera zimbudzi awa ali ndi mapaipi ambiri otsika mphamvu ndi ma valve kuti agwire ntchito yawo "yonyansa." Zofunikira pa ma valve amadzi otayira nthawi zambiri zimakhala zosavuta kuposa zofunikira pa ntchito yoyeretsa madzi oyera. Ma valve achitsulo ndi cheke ndi omwe amasankhidwa kwambiri pa ntchito yamtunduwu. Ma valve wamba mu ntchito iyi amamangidwa motsatira malangizo a AWWA.

Makampani Opanga Magetsi
Mphamvu zambiri zamagetsi zomwe zimapangidwa ku United States zimapangidwa m'mafakitale a nthunzi pogwiritsa ntchito ma turbine amafuta ndi ma turbine othamanga kwambiri. Kutsegula chivundikiro cha fakitale yamakono yamagetsi kungapangitse kuti muwone mapaipi amphamvu komanso otentha kwambiri. Mizere yayikulu iyi ndiyo yofunika kwambiri popanga mphamvu ya nthunzi.

Ma valve a pachipata akadali chisankho chachikulu pakugwiritsa ntchito magetsi, ngakhale kuti palinso ma valve a Y-pattern globe omwe amagwiritsidwa ntchito kwambiri. Ma valve a mpira ogwira ntchito bwino komanso ofunikira kwambiri akutchuka kwambiri ndi opanga magetsi ena ndipo akupita patsogolo kwambiri m'dziko lino lomwe kale linali ndi ma valve olunjika.

Kugwiritsira ntchito zitsulo n'kofunika kwambiri pa mavavu pakugwiritsa ntchito mphamvu, makamaka omwe amagwira ntchito m'malo ofunikira kwambiri kapena ofunikira kwambiri pa kuthamanga ndi kutentha. F91, F92, C12A, pamodzi ndi Inconel ndi zitsulo zosapanga dzimbiri zimagwiritsidwa ntchito kwambiri m'mafakitale amagetsi amakono. Magulu a kuthamanga ndi 1500, 2500 ndipo nthawi zina 4500. Kusinthasintha kwa mafakitale amphamvu kwambiri (omwe amagwira ntchito pokhapokha ngati pakufunika) kumaikanso mavuto aakulu pa mavavu ndi mapaipi, zomwe zimafuna mapangidwe olimba kuti athe kuthana ndi kusakanikirana kwakukulu kwa kuyendetsa njinga, kutentha ndi kuthamanga.
Kuwonjezera pa ma valavu akuluakulu a nthunzi, zomera zamagetsi zili ndi mapaipi othandizira, okhala ndi ma valavu ambirimbiri a chipata, globe, cheke, butterfly ndi ball.

Malo opangira mphamvu za nyukiliya amagwira ntchito mofanana ndi nthunzi/turbine yothamanga kwambiri. Kusiyana kwakukulu ndikuti mu malo opangira mphamvu za nyukiliya, nthunzi imapangidwa ndi kutentha kuchokera ku njira yopasuka. Ma valve a malo opangira mphamvu za nyukiliya ndi ofanana ndi abale awo omwe amagwiritsa ntchito mafuta akale, kupatulapo chifukwa cha mbiri yawo komanso kufunikira kowonjezereka kwa kudalirika kotheratu. Ma valve a nyukiliya amapangidwa pamlingo wapamwamba kwambiri, ndipo zikalata zoyenerera ndi zowunikira zimadzaza masamba mazana ambiri.

Kupanga Mafuta ndi Gasi
Zitsime za mafuta ndi gasi ndi malo opangira zinthu amagwiritsa ntchito kwambiri ma valve, kuphatikizapo ma valve ambiri olemera. Ngakhale kuti mafuta otuluka akutuluka mamita mazana ambiri mlengalenga sapezekanso, chithunzichi chikuwonetsa mphamvu ya mafuta ndi gasi pansi pa nthaka. Ichi ndichifukwa chake mitu ya zitsime kapena mitengo ya Khirisimasi imayikidwa pamwamba pa chingwe chachitali cha chitoliro cha chitsime. Mipando iyi, yokhala ndi ma valve ndi zida zapadera, idapangidwa kuti igwire mphamvu yoposa 10,000 psi. Ngakhale kuti sipezeka kawirikawiri pa zitsime zomwe zimakumbidwa pansi masiku ano, mphamvu yowonjezereka nthawi zambiri imapezeka pa zitsime zakuya za m'mphepete mwa nyanja.

Kapangidwe ka zida za Wellhead kamaphimbidwa ndi ma API monga 6A, Ma Specification a Wellhead ndi Christmas Tree Equipment. Ma valve okhala ndi 6A amapangidwira kupsinjika kwakukulu koma kutentha pang'ono. Mitengo yambiri ya Khirisimasi imakhala ndi ma valve a chipata ndi ma valve apadera otchedwa chokes. Ma chokes amagwiritsidwa ntchito kuwongolera kutuluka kwa madzi kuchokera m'chitsime.

Kuwonjezera pa mipanda ya zitsime yokha, malo ambiri othandizira amakhala ndi mafuta kapena gasi. Zipangizo zoyeretsera mafuta kapena gasi zimafuna ma valve angapo. Ma valve amenewa nthawi zambiri amakhala ndi chitsulo cha kaboni chomwe chimayesedwa ndi magulu otsika.

Nthawi zina, madzi owononga kwambiri—hydrogen sulfide—amapezeka mumtsinje wa mafuta osaphika. Zinthu zimenezi, zomwe zimatchedwanso mpweya wowawasa, zimatha kupha. Kuti muthane ndi mavuto a mpweya wowawasa, zipangizo zapadera kapena njira zopangira zinthu mogwirizana ndi NACE International MR0175 ziyenera kutsatiridwa.

Makampani Ogulitsa Kunja kwa Nyanja
Makina opayira mafuta m'madzi ndi malo opangira mafuta ali ndi ma valve ambiri opangidwa mosiyanasiyana kuti athe kuthana ndi mavuto osiyanasiyana owongolera kuyenda kwa madzi. Malowa alinso ndi ma loops osiyanasiyana owongolera ndi zida zochepetsera kupanikizika.

Pa malo opangira mafuta, mtima wa m'mitsempha yamagazi ndiye njira yeniyeni yopezera mafuta kapena gasi. Ngakhale kuti nthawi zambiri sizikhala papulatifomu yokha, makina ambiri opangira mafuta amagwiritsa ntchito mitengo ya Khirisimasi ndi makina opangira mapaipi omwe amagwira ntchito pansi pa kuya kosavomerezeka kwa mamita 10,000 kapena kuposerapo. Zipangizo zopangira mafutazi zimapangidwa motsatira miyezo yambiri ya American Petroleum Institute (API) ndipo zimatchulidwa mu API Recommended Practices (RPs) zingapo.

Pamapulatifomu akuluakulu ambiri amafuta, njira zina zimagwiritsidwa ntchito pamadzi osaphika ochokera ku chitsime. Izi zimaphatikizapo kulekanitsa madzi ndi ma hydrocarbon ndi kulekanitsa madzi a gasi ndi gasi wachilengedwe kuchokera kumadzi. Mapaipi awa a pambuyo pa mtengo wa Khirisimasi nthawi zambiri amapangidwa mogwirizana ndi American Society of Mechanical Engineers B31.3 piping codes okhala ndi ma valve opangidwa mogwirizana ndi ma valvu a API monga API 594, API 600, API 602, API 608 ndi API 609.

Zina mwa machitidwewa zingakhalenso ndi ma valve a API 6D, mpira ndi cheke. Popeza mapaipi aliwonse omwe ali papulatifomu kapena chombo chobowolera ndi amkati mwa malo opangira zinthu, zofunikira kwambiri zogwiritsira ntchito ma valve a API 6D pamapaipi sizigwira ntchito. Ngakhale kuti mitundu yambiri ya ma valve imagwiritsidwa ntchito m'machitidwe awa a mapaipi, mtundu wa ma valve womwe mungasankhe ndi valve ya mpira.

MAPAIPILINI
Ngakhale mapaipi ambiri saonekera, kupezeka kwawo nthawi zambiri kumawonekera. Zikwangwani zazing'ono zonena kuti "payipi ya petulo" ndi chizindikiro chimodzi chodziwikiratu cha kukhalapo kwa mapaipi oyendera pansi pa nthaka. Mapaipi awa ali ndi ma valve ambiri ofunikira kutalika kwawo konse. Ma valve otseka mapaipi mwadzidzidzi amapezeka nthawi ndi nthawi monga momwe zafotokozedwera ndi miyezo, malamulo ndi malamulo. Ma valve awa amagwira ntchito yofunika kwambiri yolekanitsa gawo la mapaipi ngati patuluka madzi kapena pamene pakufunika kukonza.

Palinso malo omwe mzerewu umatuluka pansi ndipo pali njira yolowera. Malo awa ndi komwe kuli zida zoyambira "nkhumba", zomwe zimakhala ndi zida zomwe zimayikidwa m'mapaipi kuti ziwunikire kapena kuyeretsa mzerewu. Malo oyambitsira nkhumba nthawi zambiri amakhala ndi ma valve angapo, kaya chipata kapena mpira. Ma valve onse omwe ali pamakina apaipi ayenera kukhala ndi doko lonse (lotseguka kwathunthu) kuti alole kuti nkhumba zidutse.

Mapaipi amafunikanso mphamvu kuti athane ndi kukangana kwa mapaipi ndikusunga kupanikizika ndi kuyenda kwa chingwe. Ma compressor kapena malo opopera omwe amawoneka ngati makina ang'onoang'ono opangira zinthu opanda nsanja zazitali zosweka amagwiritsidwa ntchito. Malo awa ali ndi ma valve ambiri a chipata, mpira ndi cheke.
Mapaipi okha amapangidwa motsatira miyezo ndi ma code osiyanasiyana, pomwe ma valve a mapaipi amatsatira ma valve a API 6D Pipeline.
Palinso mapaipi ang'onoang'ono omwe amalowa m'nyumba ndi m'nyumba zamalonda. Mizere iyi imapereka madzi ndi gasi ndipo imatetezedwa ndi ma valve otsekedwa.
Maboma akuluakulu, makamaka kumpoto kwa United States, amapereka nthunzi yotenthetsera makasitomala amalonda. Ma payipi operekera nthunzi awa ali ndi ma valve osiyanasiyana kuti azitha kuwongolera ndikuwongolera kuperekedwa kwa nthunzi. Ngakhale kuti madziwo ndi nthunzi, kupsinjika ndi kutentha kwake ndi kotsika poyerekeza ndi komwe kumapezeka popanga nthunzi ya fakitale yamagetsi. Mitundu yosiyanasiyana ya ma valve imagwiritsidwa ntchito muutumikiwu, ngakhale kuti valavu yodziwika bwino ya pulagi ikadali chisankho chodziwika bwino.

ZOPANGIRA ZOPANGIRA ZAPADERA NDI ZOPANGIRA PETROKHIMIKA
Ma valve oyeretsera mafuta ndi omwe amagwiritsidwa ntchito kwambiri m'mafakitale kuposa gawo lina lililonse la ma valve. Malo oyeretsera mafuta ndi kwawo kwa madzi owononga komanso nthawi zina kutentha kwambiri.
Zinthu izi zimalamulira momwe ma valve amamangidwira motsatira malangizo a API valve monga API 600 (ma valve a pachipata), API 608 (ma valve a mpira) ndi API 594 (onani ma valve). Chifukwa cha ntchito yovuta yomwe ma valve ambiriwa amakumana nayo, nthawi zambiri amafunika thandizo lowonjezera la dzimbiri. Thandizoli limaonekera kudzera mu makulidwe akuluakulu a makoma omwe afotokozedwa m'mapepala a API design.

Pafupifupi mitundu yonse ya ma valavu akuluakulu imapezeka m'fakitale yayikulu yoyeretsera. Vavu yopezeka paliponse ndiyo mfumu ya phiri yokhala ndi anthu ambiri, koma ma valavu ozungulira kotala akutenga gawo lalikulu pamsika wawo. Zinthu zozungulira kotala zomwe zikupita patsogolo bwino mumakampani awa (omwe kale anali olamulidwa ndi zinthu zolunjika) zimaphatikizapo ma valavu a butterfly atatu ogwira ntchito bwino komanso ma valavu a mpira okhala ndi zitsulo.

Ma valve a chipata chokhazikika, globe ndi check gate akadali kupezekabe, ndipo chifukwa cha luso lawo lopanga komanso ndalama zomwe amapanga, sizidzatha posachedwa.
Kuchuluka kwa mphamvu ya ma valve oyeretsera mafuta kumasiyana kuyambira pa Class 150 mpaka Class 1500, ndipo Class 300 ndiyo yotchuka kwambiri.
Zitsulo za kaboni wamba, monga WCB (yopangidwa ndi chitsulo) ndi A-105 (yopangidwa ndi chitsulo) ndi zinthu zodziwika kwambiri zomwe zimagwiritsidwa ntchito mu ma valve pokonza zinthu. Ntchito zambiri zoyeretsera zimapititsa patsogolo kutentha kwa zitsulo za kaboni wamba, ndipo zitsulo zotentha kwambiri zimayikidwa pazinthu izi. Zodziwika kwambiri mwa izi ndi zitsulo za chrome/moly monga 1-1/4% Cr, 2-1/4% Cr, 5% Cr ndi 9% Cr. Zitsulo zosapanga dzimbiri ndi zitsulo za nickel zapamwamba zimagwiritsidwanso ntchito pa njira zina zoyeretsera zovuta kwambiri.

MANKHWALA
Makampani opanga mankhwala amagwiritsa ntchito kwambiri ma valve amitundu yonse ndi zipangizo zosiyanasiyana. Kuyambira mafakitale ang'onoang'ono mpaka malo akuluakulu opangira mafuta omwe amapezeka ku Gulf Coast, ma valve ndi gawo lalikulu la makina opangira mapaipi a mankhwala.

Kugwiritsa ntchito kwambiri mankhwala m'njira zambiri kumakhala kotsika poyerekeza ndi njira zambiri zoyeretsera ndi kupanga magetsi. Magulu otchuka kwambiri a ma valve a zomera ndi mapaipi a mankhwala ndi Magulu 150 ndi 300. Mafakitale a mankhwala akhala akuyendetsa kwambiri msika womwe ma valve a mpira akhala akumenyana nawo kuchokera ku ma valve olunjika m'zaka 40 zapitazi. Valavu ya mpira yolimba, yokhala ndi kutseka kwake kosatulutsa madzi, ndi yoyenera kugwiritsa ntchito mafakitale ambiri a mankhwala. Kukula kochepa kwa valavu ya mpira ndi chinthu chodziwika bwino.
Palinso zomera zina zamakemikolo ndi njira zomangira zomera komwe mavavu olunjika amakondedwa. Muzochitika izi, mavavu otchuka opangidwa ndi API 603, okhala ndi makoma opyapyala komanso zolemera zopepuka, nthawi zambiri amakhala valavu yolowera kapena yozungulira yomwe imasankhidwa. Kuwongolera mankhwala ena kumachitika bwino ndi mavavu a diaphragm kapena pinch.
Chifukwa cha kuwononga kwa mankhwala ambiri komanso njira zopangira mankhwala, kusankha zinthu n'kofunika kwambiri. Chitsulo chosapanga dzimbiri cha austenitic cha 316/316L ndi chitsulo chosapanga dzimbiri cha austenitic. Chitsulochi chimagwira ntchito bwino polimbana ndi dzimbiri kuchokera ku madzi ambiri oipa omwe nthawi zina amawononga.

Pa ntchito zina zolimba zowononga, chitetezo chowonjezereka chikufunika. Zitsulo zina zosapanga dzimbiri za austenitic, monga 317, 347 ndi 321, nthawi zambiri zimasankhidwa pazochitika izi. Ma alloy ena omwe amagwiritsidwa ntchito nthawi ndi nthawi kuwongolera madzi a mankhwala ndi Monel, Alloy 20, Inconel ndi 17-4 PH.

KULEKANITSA LNG NDI GESI
Mpweya wachilengedwe wamadzimadzi (LNG) ndi njira zomwe zimafunikira pakulekanitsa mpweya zimadalira mapaipi akuluakulu. Ntchitozi zimafuna ma valve omwe amatha kugwira ntchito kutentha kochepa kwambiri. Makampani opanga LNG, omwe akukula mofulumira ku United States, akuyang'ana nthawi zonse kukonza ndikuwongolera njira yothira madzi kuchokera ku gasi. Pachifukwa ichi, mapaipi ndi ma valve akhala akukulirakulira ndipo kufunikira kwa kupanikizika kwakwezedwa.

Izi zapangitsa kuti opanga ma valve apange mapangidwe kuti akwaniritse zofunikira kwambiri. Ma valve a mpira wozungulira kotala ndi a gulugufe ndi otchuka kwambiri pa ntchito ya LNG, ndipo 316ss [chitsulo chosapanga dzimbiri] ndiye chinthu chodziwika kwambiri. ANSI Class 600 ndiye denga lopanikizika lomwe limagwiritsidwa ntchito kwambiri pa ntchito zambiri za LNG. Ngakhale kuti zinthu zozungulira kotala ndi mitundu yotchuka kwambiri ya ma valve, ma valve a chipata, globe ndi check amapezekanso m'mafakitale.

Ntchito yolekanitsa mpweya imaphatikizapo kugawa mpweya m'magawo ake oyambira. Mwachitsanzo, njira zolekanitsa mpweya zimapereka nayitrogeni, mpweya, heliamu ndi mpweya wina wochepa. Kutentha kochepa kwambiri kwa njirayi kumatanthauza kuti ma valve ambiri a cryogenic amafunika.

Mafakitale onse a LNG ndi gasi ali ndi ma valve otsika kutentha omwe ayenera kugwira ntchito m'mikhalidwe yovutayi. Izi zikutanthauza kuti makina opakira ma valve ayenera kukwezedwa kutali ndi madzi otsika kutentha pogwiritsa ntchito mpweya kapena column yoziziritsa. Column iyi ya gasi imaletsa madziwo kupanga mpira wa ayezi mozungulira malo opakira, zomwe zingalepheretse tsinde la valavu kutembenuka kapena kukwera.

NYUMBA ZA MALONDA
Nyumba zamalonda zimatizungulira koma pokhapokha titayang'anitsitsa pamene zikumangidwa, sitidziwa zambiri zokhudza kuchuluka kwa mitsempha yamadzimadzi yobisika mkati mwa makoma awo a miyala yamwala, galasi ndi chitsulo.

Madzi ndi chinthu chofanana pafupifupi m'nyumba iliyonse. Nyumba zonsezi zili ndi mapaipi osiyanasiyana omwe amanyamula zinthu zambiri monga hydrogen/oxygen monga madzi akumwa, madzi otayira, madzi otentha, madzi a imvi ndi chitetezo cha moto.

Poganizira za kupulumuka kwa nyumba, makina ozimitsa moto ndi ofunikira kwambiri. Chitetezo cha moto m'nyumba nthawi zambiri chimaperekedwa ndi madzi oyera. Kuti makina ozimitsa moto azigwira ntchito bwino, ayenera kukhala odalirika, okhala ndi mphamvu zokwanira komanso opezeka mosavuta m'nyumba yonse. Makina amenewa apangidwa kuti azigwira ntchito yokha ngati moto wayamba.
Nyumba zazitali zimafuna ntchito yofanana ya madzi pansi pamwamba monga pansi pansi kotero mapampu amphamvu ndi mapaipi ayenera kugwiritsidwa ntchito kuti madzi akwere. Mapaipi nthawi zambiri amakhala a Class 300 kapena 600, kutengera kutalika kwa nyumba. Mitundu yonse ya ma valve imagwiritsidwa ntchito mu ntchito izi; komabe, mapangidwe a ma valve ayenera kuvomerezedwa ndi Underwriters Laboratories kapena Factory Mutual kuti agwire ntchito yoyatsira moto.

Mitundu ndi mitundu yomweyi ya ma valve omwe amagwiritsidwa ntchito pa ma valve ozimitsa moto amagwiritsidwa ntchito pogawa madzi akumwa, ngakhale kuti njira yovomerezeka si yokhwima kwambiri.
Makina oziziritsira mpweya amalonda omwe amapezeka m'nyumba zazikulu zamabizinesi monga nyumba zamaofesi, mahotela ndi zipatala nthawi zambiri amakhala pakati. Ali ndi chitofu chachikulu kapena boiler kuti aziziritse kapena kutentha madzi omwe amagwiritsidwa ntchito kusamutsa kuzizira kapena kutentha kwambiri. Makinawa nthawi zambiri amafunika kugwira mafiriji monga R-134a, hydro-fluorocarbon, kapena pankhani ya makina akuluakulu otenthetsera, nthunzi. Chifukwa cha kukula kochepa kwa ma valve a gulugufe ndi mpira, mitundu iyi yatchuka kwambiri m'makina oziziritsira a HVAC.

Kumbali ya nthunzi, ma valve ena ozungulira kotala agwiritsidwa ntchito, komabe mainjiniya ambiri a mapaipi amadalirabe ma valve a chipata cholunjika ndi ma globe, makamaka ngati mapaipiwo akufuna ma butt-weld ends. Pa ntchito zotsika mtengo za nthunzizi, chitsulo chalowa m'malo mwa chitsulo chopangidwa chifukwa cha kusinthasintha kwa chitsulo.

Makina ena otenthetsera amagwiritsa ntchito madzi otentha m'malo mwa nthunzi ngati madzi osamutsira. Makinawa amatumikiridwa bwino ndi ma valve amkuwa kapena achitsulo. Ma valve a mpira ndi agulugufe okhala ndi ma quarter-turn ndi otchuka kwambiri, ngakhale kuti mapangidwe ena a mzere amagwiritsidwabe ntchito.

MAPETO
Ngakhale umboni wa ma valve omwe atchulidwa m'nkhaniyi sungawonekere paulendo wopita ku Starbucks kapena kunyumba kwa agogo, ma valve ena ofunikira kwambiri amakhala pafupi nthawi zonse. Palinso ma valve mu injini ya galimoto omwe amagwiritsidwa ntchito kufika kumalo monga omwe ali mu carburetor omwe amawongolera kuyenda kwa mafuta kulowa mu injini ndi omwe ali mu injini omwe amawongolera kuyenda kwa mafuta kulowa mu ma piston ndikutulukanso. Ndipo ngati ma valve amenewo sali pafupi mokwanira ndi moyo wathu watsiku ndi tsiku, ganizirani zenizeni kuti mitima yathu ikugunda nthawi zonse kudzera muzipangizo zinayi zofunika kwambiri zowongolera kuyenda kwa madzi.

Ichi ndi chitsanzo china cha zenizeni kuti: ma valve ali paliponse.
Gawo Lachiwiri la nkhaniyi likufotokoza za mafakitale ena omwe ma valve amagwiritsidwa ntchito. Pitani ku www.valvemagazine.com kuti muwerenge za zamkati ndi mapepala, ntchito za m'madzi, madamu ndi mphamvu zamagetsi, dzuwa, chitsulo ndi chitsulo, ndege, kutentha kwa dziko lapansi, ndi kupanga ndi kusungunula zinthu zaluso.

GREG JOHNSON ndi purezidenti wa United Valve (www.unitedvalve.com) ku Houston. Iye ndi mkonzi wothandizira wa VALVE Magazine, yemwe kale anali wapampando wa Valve Repair Council komanso membala wa bungwe la VRC. Iyenso ndi membala wa Komiti Yophunzitsa ndi Kuphunzitsa ya VMA, ndi wachiwiri kwa wapampando wa Komiti Yolankhulana ya VMA ndipo kale anali purezidenti wa bungwe la Manufacturers Standardization Society.