Vavu yoyimitsa imagwiritsidwa ntchito makamaka poyendetsa ndikuletsa madzi kuyenda kudzera mu payipi. Amasiyana ndi mavavu monga mavavu a mpira ndi mavavu a chipata chifukwa adapangidwa kuti azilamulira kuyenda kwa madzi ndipo sikuti amangogwira ntchito zotseka. Chifukwa chomwe valavu yoyimitsa imatchulidwira chonchi ndichakuti kapangidwe kakale kamakhala ndi thupi linalake lozungulira ndipo kangagawidwe m'magawo awiri, olekanitsidwa ndi equator, komwe kuyenda kumasintha njira. Zinthu zenizeni zamkati mwa mpando wotseka nthawi zambiri sizikhala zozungulira (monga mavavu a mpira) koma nthawi zambiri zimakhala zozungulira, zozungulira, kapena zooneka ngati pulagi. Mavavu a globe amaletsa kuyenda kwa madzi kuyenda kwambiri akamatsegulidwa kuposa mavavu a chipata kapena mpira, zomwe zimapangitsa kuti kuthamanga kudutse kwambiri. Mavavu a globe ali ndi mawonekedwe atatu akuluakulu a thupi, ena mwa iwo amagwiritsidwa ntchito kuchepetsa kutsika kwa kuthamanga kudzera mu valavu. Kuti mudziwe zambiri za mavavu ena, chonde onani Buku lathu la ogula mavavu.

Kapangidwe ka valavu

Valavu yoyimitsa imapangidwa ndi magawo atatu akuluakulu:thupi la valavu ndi mpando, diski ya valavu ndi tsinde, kulongedza ndi bonnet. Mukagwira ntchito, tembenuzani tsinde lolumikizidwa kudzera mu chiwongolero cha dzanja kapena choyeretsera valavu kuti mukweze diski ya valavu kuchokera pampando wa valavu. Njira yamadzimadzi kudzera mu valavu ili ndi njira yooneka ngati Z kotero kuti madzimadzi amatha kukhudza mutu wa diski ya valavu. Izi ndizosiyana ndi ma valavu a chipata komwe madzimadzi amakhala olunjika ku chipata. Kapangidwe kameneka nthawi zina kamafotokozedwa ngati thupi la valavu yooneka ngati Z kapena valavu yooneka ngati T. Cholowera ndi chotulutsira zimagwirizana.

Mapangidwe ena amaphatikizapo ma angles ndi mapatani ooneka ngati Y. Mu valavu yoyimitsa ngodya, malo otulukira mpweya ali pa 90 ° kuchokera ku malo olowera mpweya, ndipo madziwo amayenda motsatira njira yooneka ngati L. Mu kapangidwe ka thupi la valavu yooneka ngati Y kapena Y, tsinde la valavu limalowa m'thupi la valavu pa 45 °, pomwe malo olowera mpweya ndi malo otulukira mpweya amakhalabe pamzere, mofanana ndi mu njira ya njira zitatu. Kukana kwa pateni ya angular kuti iyende bwino ndi kochepa kuposa kwa pateni yooneka ngati T, ndipo kukana kwa pateni yooneka ngati Y ndi kochepa. Ma valve atatu ndi omwe amapezeka kwambiri mwa mitundu itatuyi.

Chidebe chotsekera nthawi zambiri chimakhala chopindika kuti chigwirizane ndi mpando wa valavu, koma chidebe chosalala chingagwiritsidwenso ntchito. Vavu ikatsegulidwa pang'ono, madziwo amayenderera mofanana mozungulira chidebecho, komanso kufalikira kwa valavu pampando ndi chidebecho. Chifukwa chake, valavu imagwira ntchito bwino pamene madzi akuyenda pang'onopang'ono. Nthawi zambiri, njira yoyendera imakhala mbali ya tsinde la valavu, koma pamalo otentha kwambiri (nthunzi), pamene thupi la valavu lizizira ndikuchepa, madziwo nthawi zambiri amabwerera m'mbuyo kuti valavu isunge chidebecho chotsekedwa bwino. Vavu imatha kusintha njira yoyendera kuti igwiritse ntchito kupanikizika kuti ithandize kutseka (kuyenda pamwamba pa diski) kapena kutseguka (kuyenda pansi pa diski), motero kulola valavu kutseka kapena kulephera kutseguka.

Chimbale chotsekera kapena pulagiNthawi zambiri imatsogozedwa pansi kupita ku mpando wa valavu kudzera mu khola kuti zitsimikizire kuti zikugwirizana bwino, makamaka pakugwiritsa ntchito mphamvu zambiri. Mapangidwe ena amagwiritsa ntchito mpando wa valavu, ndipo chisindikizo chomwe chili mbali ya ndodo ya valavu ya disc chimalumikizana ndi mpando wa valavu kuti chitulutse mphamvu pa cholongedza pamene valavu yatsegulidwa kwathunthu.

Malinga ndi kapangidwe ka chinthu chotsekera, valavu yoyimitsa imatha kutsegulidwa mwachangu potembenuza kangapo tsinde la valavu kuti iyambe kuyenda mwachangu (kapena kutsekedwa kuti imise kuyenda), kapena kutsegulidwa pang'onopang'ono ndi kuzungulira kangapo kwa tsinde la valavu kuti ipange kuyenda koyenera kudzera mu valavu. Ngakhale kuti mapulagi nthawi zina amagwiritsidwa ntchito ngati zinthu zotsekera, sayenera kusokonezedwa ndi mavalavu a pulagi, omwe ndi zida zozungulira kotala, zofanana ndi mavalavu a mpira, omwe amagwiritsa ntchito mapulagi m'malo mwa mipira kuti ayimitse ndikuyamba kuyenda.

ntchito

Ma valve oletsa madzi amagwiritsidwa ntchito potseka ndikuwongolera malo oyeretsera madzi otayira, malo opangira magetsi ndi malo opangira zinthu. Amagwiritsidwa ntchito m'mapaipi a nthunzi, malo oziziritsira madzi, makina odzola mafuta, ndi zina zotero, momwe kuwongolera kuchuluka kwa madzi omwe amadutsa m'ma valve kumachita gawo lofunika kwambiri.

Kusankha zinthu zomwe zili m'thupi la valavu ya padziko lonse nthawi zambiri kumakhala chitsulo chopangidwa kapena mkuwa / bronze pogwiritsa ntchito mphamvu zochepa, ndipo chitsulo cha kaboni chopangidwa kapena chitsulo chosapanga dzimbiri chogwiritsidwa ntchito ndi mphamvu zambiri komanso kutentha kwambiri. Zinthu zomwe zafotokozedwa m'thupi la valavu nthawi zambiri zimakhala ndi ziwalo zonse zopanikizika, ndipo "trim" imatanthauza zigawo zina kupatula thupi la valavu, kuphatikizapo mpando wa valavu, diski ndi tsinde. Kukula kwakukulu kumatsimikiziridwa ndi gulu la ASME class pressure, ndipo mabolts wamba kapena ma welding flanges amalamulidwa. Kukula kwa mavalavu a padziko lonse kumafuna khama lalikulu kuposa kukula kwa mitundu ina ya mavalavu chifukwa kutsika kwa mphamvu kudutsa valavu kungakhale vuto.

Kapangidwe ka tsinde lokwera ndi komwe kumapezeka kwambiri m'ma valavu oimitsa, koma ma valavu okwera omwe sakwera amapezekanso. Bonnet nthawi zambiri imamangidwa ndipo imatha kuchotsedwa mosavuta mukamayang'ana mkati mwa valavu. Mpando wa valavu ndi diski ndizosavuta kusintha.

Ma valve oletsanthawi zambiri zimagwiritsidwa ntchito zokha pogwiritsa ntchito piston ya pneumatic kapena diaphragm actuators, zomwe zimagwira ntchito mwachindunji pa tsinde la valavu kuti zisunthe diskiyo pamalo ake. Piston/diaphragm imatha kuyikidwa m'malo mwa kasupe kuti itsegule kapena kutseka valavu ikataya mphamvu ya mpweya. Choyendetsa magetsi chozungulira chimagwiritsidwanso ntchito.