Uma abantu becabanga ukuthi imishini yezimboni iyaphela, bacabanga ngamabheringi agugile, ama-motor ashile, noma uphawu olugcine luphelile. Onjiniyela bezitshalo bayazi ukuthi ngokuvamile kuyinto engavamile kunalokho. Iphampu ingaba yintsha sha, ibe nosayizi ofanele, futhi iqhubeke izidla iphila phakathi nonyaka ngenxa yenombolo eyodwa engaqondwa kahle kudathashethi.
Leyo nombolo ibizwa ngokuthi i-NPSH. Uma ungakaze ubhekane namaphampu, kuzwakala sengathi yi-alfabhethi. Kodwa umqondo ongemuva kwayo uchaza ingxenye enkulu yokwehluleka okungaqondakali okugcina abaphathi bezikhungo bephapheme ebusuku.
Ngakho-ke kuyini, futhi kungani ukukulungisa ngendlela engalungile kuphazamisa ihadiwe ebizayo?
I-NPSH ngesiNgisi Esilula
Inhloko Yokumunca Okuhle ilinganisa ukuthi uketshezi lunengcindezi engakanani ngaphezu kwephuzu lalo lokubila ngesikhathi lungena epompo. Hhayi izinga lokushisa. Ingcindezi. Noma yiluphi uketshezi lungabila ekushiseni kwegumbi uma ingcindezi yehla kakhulu, futhi yilowo mgibe.
Iphampu ngayinye inezinombolo ezimbili zalezi. I-NPSH Available (NPSHA) yilokho uhlelo olukulethayo ngempela endaweni yokungena yephampu. I-NPSH Required (NPSHR) yilokho iphampu ekudingayo ukuze isebenze ngaphandle kokuthi uketshezi lukhanye lube umhwamuko ngaphakathi kuyo.
Uma Kutholakala kuwela ngaphansi Kuyadingeka, uketshezi luqala ukubila khona kanye ku-impeller. Lokho kuyisicaba, futhi kuyisihluku.
Kungani Umthetho Wamaphesenti Amathathu Kusukela Ngo-1932 Usaqhubeka Nemboni
Nansi ingxenye emangaza abantu. Inombolo ye-NPSHR kuma-curve amaningi ephampu akuyona indawo lapho iphampu iyeka ukusebenza khona. Iphawula indawo lapho ukusebenza sekuvele kwehle khona. Kusukela ngo-1932, i-Hydraulic Institute yavumelana nokwehla kwekhanda ngamaphesenti amathathu ngesilinganiso sokugeleza esingaguquki njengencazelo esemthethweni, ngoba lelo kwakuyishintsho elincane kakhulu ababengalilinganisa ngokuthembekile esitendini sokuhlola.
Izinga lomkhakha lamiswa cishe eminyakeni eyikhulu edlule ngokusekelwe kulokho okungalinganiswa, hhayi kulokho okuvikela iphampu. Ngesikhathi ucindezela i-NPSHR eshicilelwe, amabhamuza e-cavitation asevele ewa ngaphakathi kwe-impeller isikhathi esithile. Awakashintshi ukusebenza okwanele ukuze kubonakale ku-gauge.
Yingakho abaklami abanolwazi bengagijimi e-NPSHR. Bagijima ngomkhawulo. Futhi ubukhulu balowo mkhawulo yilapho izimpikiswano zangempela zenzeka khona.
Umdlalo We-Margin
Ngakho-ke udinga malini engeziwe? Impendulo eqotho: kuncike kulokho okupompayo, ukuthi kushesha kangakanani, nokuthi kufakwe amandla angakanani emhubheni. Isiqondiso se-Hydraulic Institute sinikeza izilinganiso eziqondiwe zezimboni ezahlukene. Ngokusho kwesifinyezo sakamuva se-ANSI/HI 9.6.1, indinganiso manje ihlanganisa izingxenye eziyishumi zemakethe ezihlukene, okuhlanganisa amaphampu enqubo kaphethiloli, amaphampu enqubo yamakhemikhali, amandla kagesi, kanye namanzi angcolile.
Izilinganiso ezishicilelwe ziphansi kunalokho abantu abaningi abakuqagelayo. Ezinhlelweni zokusebenza ezisebenzisa amandla aphansi njengemibhoshongo yokupholisa kanye namaphampu amanzi angcolile ensimbi, izilinganiso ze-margin ezinconywayo zingaphezu kuka-1 kuphela, okusho ukuthi i-NPSHA ayisusi kahle i-NPSHR. Izwakala incane. Ezimpampini ezisebenzisa amandla aphansi, kulungile.
Imishini ekhipha amandla amaningi iyisilwane esihlukile. Iqembu elisebenzayo ngaphakathi kwe-Hydraulic Institute linayo imingcele enconyiwe ifinyelela phezulu njenge-NPSHR ephindwe kane, okusho isilinganiso se-NPSHA/NPSHR esingu-1 kuya ku-5. Isiphetho esiphezulu singesamaphampu aphethe i-kinetic punch eningi kakhulu.
Lapho Ukuphela Kodwa Kunganele
Manje ingxenye engakhululekile. Ngisho nenani elikhulu alikusindisi ngaso sonke isikhathi. Izincwadi zemboni zichaza amaphampu amakhulu okudla kwebhoyila aklanywe nge-NPSHA cishe kabili kune-NPSHR eshicilelwe, okungaphezu kwalokho okwakufunwa yi-datasheet.
Ama-impeller esigaba sokuqala, enziwe ngensimbi engagqwali ye-CA6NM, ahlala isikhathi esingangonyaka ngaphambi kokuba umonakalo we-cavitation uphoqe ukushintshwa. Umkhawulo ophindwe kabili kunalowo owawucelwe yincwadi, futhi ipompo yayisalokhu izihlafuna ngomjikelezo waminyaka yonke.
Izifundo ezinjengalezo yingakho abanye abakhiqizi becaphuna i-spec ehlukile ngezinye izikhathi ebhalwe njenge-NPSH enombhalo ongaphansi wesikhathi eside. Hlangana nalelo nani futhi umthengisi akaqinisekisi ukulahlekelwa ukusebenza noma ukushintshwa kwezingxenye phakathi nomjikelezo ochaziwe weminyaka eminingi wokusebenza okuqhubekayo. Kuyindlela ehlukile yokuthi inombolo yeshidi ledatha ngeke ikuvikele, kodwa lena izokuvikela.
Kusho ukuthini lokhu uma uthenga, ucacisa, noma ufuna ukwazi nje
Akudingeki ube unjiniyela wemishini ojikelezayo ukuze uthathe okuthile okusebenzayo kulokhu.
Kunezimiso ezimbalwa ezifinyelela kude ngendlela emangalisayo:
- Phatha i-NPSHR njengesitezi, hhayi isitha. Uma isiphakamiso sibonisa ukuthi i-NPSHA ingaphezulu kancane kwe-NPSHR, lokho kuyisibonakaliso esibomvu, hhayi ukudlula. Cela ngokucacile isilinganiso semargin.
- Buza ngamandla okumunca. Amaphampu amabili anenani elifanayo le-NPSHR angaziphatha ngendlela ehluke ngokuphelele ngaphansi komkhawulo ofanayo. Amandla aphezulu okumunca adinga indawo enkulu yokusebenza.
- Funa isiqondiso esiqondene nesicelo. Isilinganiso esifanele sombhoshongo wokupholisa singaba yingozi ku-boiler feed. Ingxenye yemakethe ibaluleke kakhulu kunomthetho ojwayelekile.
- Qaphela indawo yokusebenza. Iphampu egijima kude nendawo yayo yokusebenza kahle kakhulu iziphatha kabi kunalokho okubikezelwa yi-datasheet, futhi i-NPSHR ngokwayo ikhuphuka iye phezulu kakhulu.
- Isabelomali sokuhlolwa. Umonakalo we-cavitation ubonakala kuma-ine e-impeller isikhathi eside ngaphambi kokuba ubonakale ezinombolo zokugeleza. Uma ulinda ukuthi i-pressure gauge ikutshele, i-impeller isivele ilahlekile.
Akukho kulokhu okuwulwazi olungavamile. Umehluko phakathi kwephampu esebenza kahle iminyaka eyishumi kanye nephampu eba yinto ephindaphindayo kusabelomali sokulungisa. Inombolo efihliwe kushidi ledatha inquma ukuthi iyiphi oyitholayo.