Xa abantu becinga ngezixhobo zoshishino ezingasebenziyo, bacinga ngeebheringi ezigugileyo, iimoto ezitshileyo, okanye isitywini esiye saphela ekugqibeleni. Iinjineli zezityalo ziyazi ukuba ngokuqhelekileyo ayiqhelekanga loo nto. Ipompo inokuba yintsha, ilinganiswe ngokuchanekileyo, kwaye ingazitya iphila ngaphakathi konyaka ngenxa yenani elinye elingaqondwa kakuhle kwiphepha ledatha.
Elo nani libizwa ngokuba yi-NPSH. Ukuba awukaze ujongane neepompo, livakala ngathi liyi-alfabhethi. Kodwa ingcamango engasemva kwalo ichaza inxalenye enkulu yokusilela okungaqondakaliyo okugcina abaphathi beziko bephaphile ebusuku.
Yintoni ke ngoko, kwaye kutheni ukuphosakela kuphazamisa izixhobo ezibizayo?
I-NPSH kwisiNgesi esicacileyo
Intloko yeNet Positive Suction ilinganisa ukuba ulwelo lunoxinzelelo olungakanani ngaphezu kweqondo lokubila kwalo xa lungena kwipompo. Hayi ubushushu. Uxinzelelo. Naluphi na ulwelo lunokubila kubushushu begumbi ukuba uxinzelelo lwehla kakhulu, kwaye yiloo nto inokubangela ukuba kubekho uxinzelelo.
Ipompo nganye inamanani amabini kula. I-NPSH Available (NPSHA) yinto enikezelwa yinkqubo kwindawo yokungena yepompo. I-NPSH Required (NPSHR) yinto efunekayo ukuze ipompo isebenze ngaphandle kokuba ulwelo lukhanye lube ngumphunga ngaphakathi kuyo.
Ukuba ifumaneka ihla ngaphantsi kwemfuneko, ulwelo luqala ukubila ngqo kwi-impeller. Yi-cavitation leyo, kwaye imbi kakhulu.
Kutheni uMthetho weepesenti ezi-3 ukususela ngo-1932 usaqhuba ishishini?
Nantsi inxalenye ebamangalisayo abantu. Inombolo ye-NPSHR kwiikhova ezininzi zepompo ayisiyondawo apho ipompo iyeka ukusebenza. Iphawula indawo apho ukusebenza sele kwehle khona. Kwangoko ngo-1932, iHydraulic Institute yagqiba ekubeni i-3% yehle ngentloko ngesantya sokuhamba esingaguqukiyo njengengcaciso esemthethweni, kuba olo yayilolona tshintsho luncinci ababenokululinganisa ngokuthembekileyo kwindawo yokuvavanya.
Umgangatho weshishini wamiselwa phantse kwiminyaka elikhulu eyadlulayo ngokusekelwe kwinto enokulinganiswa, kungekhona kwinto ekhusela ipompo. Ngexesha ufika kwi-NPSHR epapashiweyo, amaqamza e-cavitation sele ewile ngaphakathi kwi-impeller okwethutyana. Awakabonakali ukusebenza ngokwaneleyo ukuba kubonakale kwi-gauge.
Yiyo loo nto abayili abanamava bengasebenzi kwi-NPSHR. Basebenza ngomda. Kwaye ubungakanani baloo mda kulapho iingxoxo zokwenyani zenzeka khona.
Umdlalo weMargin
Ngoko ke ufuna malini eyongezelelweyo? Impendulo enyanisekileyo: kuxhomekeke kwinto oyipompayo, ukuba ikhawuleza kangakanani, kwaye ingakanani amandla afakwe kwi-suction. Isikhokelo se-Hydraulic Institute sinika iithagethi ezijolise kuzo kumashishini ahlukeneyo. Ngokwesishwankathelo sohlaziyo lwakutshanje lwe-ANSI/HI 9.6.1, umgangatho ngoku ugubungela amacandelo alishumi ahlukeneyo emarike, kubandakanya iipompo zenkqubo yepetroliyam, iipompo zenkqubo yeekhemikhali, umbane, kunye namanzi amdaka.
Ubuncinane obushicilelweyo buphantsi kunokuba uninzi lwabantu lucinga. Kwizicelo ezisebenzisa amandla aphantsi njengee-cooling towers kunye nee-cast-iron wastewater pumps, i-margin ratios ecetyiswayo ingaphezulu kwe-1 kancinci, oko kuthetha ukuba i-NPSHA ayisusi kangako i-NPSHR. Ivakala ngathi incinci. Kwiipompo ezisebenzisa amandla aphantsi, kulungile.
Oomatshini abafunxa amandla aphezulu bahlukile. Iqela elisebenzayo ngaphakathi kwiHydraulic Institute linayo imida ecetyiswayo ifikelela kwi-NPSHR ephindwe kane, oko kuthetha ukuba umlinganiselo we-NPSHA/NPSHR ngu-1 ukuya ku-5. Isiphelo esiphezulu seso seempompo ezithwala i-kinetic punch kakhulu.
Xa iMargin yodwa inganelanga
Ngoku le yinxenye engonwabisiyo. Nokuba yimali eninzi ayikuncedi rhoqo. Uncwadi lweshishini luchaza iimpompo ezinkulu zebhoyila eziyilwe nge-NPSHA malunga ne-NPSHR epapashiweyo kabini, ngaphaya koko bekufunwa yidatha.
Ii-impellers zenqanaba lokuqala, ezenziwe ngentsimbi engagqwaliyo ye-CA6NM, zahlala ixesha elingangonyaka ngaphambi kokuba umonakalo owenziwe yi-cavitation unyanzeleke ukuba itshintshwe. Iphindwe kabini kunomlinganiselo owawuceliwe yincwadi yesandla, kwaye ipompo yayisahlafuna ngokwahlukileyo kumjikelo wonyaka.
Izifundo ezinje zezona zizathu zokuba abanye abavelisi bacaphula i-spec enye ngamanye amaxesha ebhalwe njenge-NPSH ene-subscript yexesha elide. Landelela elo xabiso kwaye umthengisi akaqinisekisi ukuba akukho lahleko yokusebenza okanye ukutshintshwa kwezixhobo ngexesha lokusebenza okuqhubekayo kweminyaka emininzi. Yindlela eyahlukileyo yokuthi inombolo yedatha ayizukukukhusela, kodwa le iya kukukhusela.
Kuthetha ukuthini oku ukuba uthenga, ucacisa, okanye unomdla nje
Akunyanzelekanga ukuba ube yinjineli yezixhobo ezijikelezayo ukuze uthathe into esebenzayo koku.
Kukho imigaqo embalwa ethetha lukhulu ngokumangalisayo:
- Phatha i-NPSHR njengomgangatho, kungekhona ithagethi. Ukuba isindululo sibonisa ukuba i-NPSHA ingaphezulu kancinci kwe-NPSHR, loo nto ithetha ukuba akukho mfuneko yokuba uphumelele. Cela ngokucacileyo umlinganiselo we-margin.
- Buza ngamandla okufunxa. Iimpompo ezimbini ezinexabiso elifanayo le-NPSHR zinokuziphatha ngendlela eyahlukileyo ngokupheleleyo phantsi komda ofanayo. Amandla aphezulu okufunxa afuna indawo engaphezulu yokubeka iliso.
- Khangela ulwalathiso oluhambelana nesicelo esithile. Umda ofanelekileyo kwinqaba yokupholisa unokuba yingozi kwi-boiler feed. Icandelo lemarike libaluleke ngaphezu komthetho oqhelekileyo.
- Jonga indawo yokusebenza. Ipompo ebaleka kude nendawo yayo yokusebenza kakuhle iziphatha kakubi kunokuba ishidi ledatha liqikelela, kwaye i-NPSHR ngokwayo inyuka iye phezulu kwiindawo ezingaphaya kwamandla.
- Uhlahlo-lwabiwo mali lokuhlolwa. Umonakalo we-cavitation ubonakala kwii-impeller vanes kudala ngaphambi kokuba ubonakale kumanani okuhamba kwamanzi. Ukuba ulinda i-pressure gauge ikuxelele, i-impeller sele ilahliwe.
Akukho nanye kwezi zinto eyolwazi olungaqhelekanga. Ngumahluko phakathi kwepompo esebenza kakuhle iminyaka elishumi kunye nenye eba yinto ephindaphindayo kuhlahlo-lwabiwo mali lokugcinwa. Inombolo efihliweyo kwiphepha ledatha igqiba ukuba yeyiphi oyifumanayo.