Phakathi kwabasebenzisi abasebenzisa-amavalvu okumisa ububanzi bobubanzi nsuku zonke, abantu bavame ukubika inkinga, okungukuthi,{1}}amavalvu okumisa amamitha amakhulu kuvamise ukuba nzima ukuvaleka lapho esetshenziswa kumidiya enomehluko omkhulu wokucindezela, njengesitimu,{2}}amanzi okucindezela okuphezulu, njll., lapho esebenza ngaphansi kwengcindezi. Vala ngamandla, kuhlale kutholakala ukuthi kuzoba nokuvuza, futhi kunzima ukuvala ngokuqinile. Isizathu sale nkinga ukuntuleka kwesakhiwo se-valve kanye ne-torque yokuphuma kwezinga lomkhawulo womuntu.
Ukuhlaziywa Kwezimbangela Zobunzima Ekuvuleni Nokuvalwa Kwamavalvu Amakhulu Amakhulu
Amandla amakhulu okukhipha avundlile omuntu omdala ojwayelekile angama-60-90kg, kuya ngezimo ezihlukene.
Ngokuvamile, indlela yokugeleza-ye-valve yokuvala yakhelwe ukuthi ibe ngaphansi futhi ibe phezulu. Lapho umuntu evala i-valve, umzimba womuntu uphusha isondo lesandla liye phezulu ukuze i-valve disc ibheke phansi ukuze ivaleke. Ngalesi sikhathi, inhlanganisela yamandla amathathu idinga ukunqotshwa, okungukuthi:
(1) I-axial thrust Fa;
(2) Ukungqubuzana phakathi kokupakisha ne-valve stem Fb;
(3) Amandla okushayisana Fc okuthintana phakathi kwesiqu sevalvu kanye nengqikithi yevalvu
Itorque ephelele ngu-∑M=(Fa+Fb+Fc)R
Kuyabonakala ukuthi ubukhulu be-outlet bukhulu, bukhulu amandla we-axial thrust. Uma iseduze nesimo esivaliwe, amandla e-axial thrust acishe asondele kumfutho wangempela wenethiwekhi yamapayipi (ngoba i-P1-P2≈P1, P2=0 uma ivaliwe)
Isibonelo, uma ivalvu yokumisa i-DN200 isetshenziswa epayipini lesitimu lamabha angu-10, into yokuqala kuphela evala i-axial thrust engu-Fa=10×}×πr2=3140kg, futhi amandla ayisiyingi avundlile adingekayo ukuze kuvalwe aseduze nokukhishwa kwendingilizi evundlile yomzimba womuntu ovamile. Umkhawulo wamandla, ngakho-ke kunzima kakhulu kumuntu oyedwa ukuvala ngokuphelele i-valve ngaphansi kwezimo ezinjalo zokusebenza.
Yiqiniso, ezinye izimboni zisikisela ukuthi lolu hlobo lwe-valve lufakwe ohlangothini oluphambene, oluxazulula inkinga yobunzima bokuvala, kodwa futhi kunenkinga yobunzima ekuvuleni ngemva kokuvalwa.
Ukuhlaziywa Kwezimbangela Zokuvuza Kwangaphakathi Kwe-Large Diameter Globe Valves
Amavalvu amakhulu-angama-diameter stop valves ngokuvamile asetshenziswa kuma-boiler outlets,{1}}kumasilinda amancane, ama-steam main, njll. Lezi zindawo zinezinkinga ezilandelayo:
(1) Ngokuvamile, umehluko wengcindezi endaweni yokuphuma kubhayela mkhulu uma kuqhathaniswa, ngakho izinga lokugeleza kwesitimu nalo likhulu, futhi nomonakalo wokuguguleka endaweni evalekayo nawo mkhulu. Ukwengeza, ukusebenza kahle komlilo we-boiler akukwazi ukuba ngu-100%, okuzokwenza ukuthi umusi ekuphumeni kwe-boiler ube nomthamo omkhulu wamanzi, okungenzeka kubangele ukulimala kwe-cavitation kanye ne-cavitation endaweni yokuvala i-valve.
(2) Ekuvaleni-ivalvu eseduze nendawo yokuphuma kubhayela kanye{2}}nesilinda, ngenxa yokuthi isitimu esiphuma kubhayela sinezinto ezithile ezishisa kakhulu, phakathi nenqubo yokugcwala, uma ukuthambisa amanzi kubhayela kungekuhle kakhulu, ingxenye yawo ngokuvamile izoba nemvula. I-Acid ne-alkali izinto zizodala ukugqwala nokuguguleka endaweni evalayo; ezinye izinto ezicwebezelayo zingase zinamathele endaweni evalekayo futhi zicwebezele, okubangele ukuthi ivalvu yehluleke ukuvala ngokuqinile.
(3)-Ama-valve afaka isilinda angaphansi kanye nama-outlet valves. Inani le-steam elisetshenziswe ngemva kwe-valve ngezinye izikhathi likhulu noma lincane ngenxa yezidingo zokukhiqiza nezinye izizathu. Uma izinga lokugeleza lishintsha kakhulu, kulula ukubangela ukukhanya, i-cavitation, njll. Ibangela ukuguguleka, i-cavitation kanye neminye imiphumela elimazayo endaweni yokuvala i-valve.
4 Kodwa-ke, kule nqubo, ukuvulwa kwe-valve kuvame ukuba kuncane kakhulu, okwenza izinga lokuguguleka libe likhulu kakhulu kunomphumela ovamile wokusetshenziswa, futhi kunciphisa kakhulu impilo yesevisi yendawo yokuvala i-valve.
Izisombululo Zokuvula Nobunzima Bokuvula Nokuvalwa Kwamavalvu Amakhulu E-Diameter Globe
(1) Okokuqala, kutuswa ukukhetha isivunguvungu-ivalvu yeglowubhu evaliwe ukuze ugweme ukumelana nokushayisana kwe-valve ye-plunger kanye nevalvu yokupakisha futhi wenze ukushintsha kube lula.
(2) I-valve core kanye nesihlalo kufanele kwenziwe ngezinto ezikwazi ukumelana nokuguguleka nokuguga, njenge-Stellite cemented carbide;
(3) Kunconywa ukuba yamukele isakhiwo se-disc ye-valve ephindwe kabili, engeke ibangele ukuguguleka ngokweqile ngenxa yokuvulwa okuncane, okuzothinta impilo yesevisi kanye nomphumela wokuvala.
