Anthu akamaganiza kuti zida zamafakitale zawonongeka, amaganiza kuti mabearing awonongeka, injini zopsereza, kapena chisindikizo chomwe chatha ntchito. Akatswiri a mafakitale amadziwa kuti nthawi zambiri zimakhala zachilendo kuposa zimenezo. Pampu ikhoza kukhala yatsopano, kukula koyenera, ndipo imadzidya yokha mkati mwa chaka chimodzi chifukwa cha nambala imodzi yosamveka bwino pa datasheet.
Nambala imeneyo imatchedwa NPSH. Ngati simunayambe mwagwirapo ntchito ndi ma pumps, imamveka ngati njira yodziwira zilembo. Koma lingaliro lomwe lili kumbuyo kwake likufotokoza zambiri za kulephera kwachinsinsi komwe kumalepheretsa oyang'anira malo kukhala maso usiku.
Ndiye n’chiyani, ndipo n’chifukwa chiyani kulakwitsa kumawononga zipangizo zokwera mtengo?
NPSH mu Chingerezi Chosavuta
Net Positive Suction Head Amayesa kuchuluka kwa mphamvu ya madzi yomwe ili pamwamba pa kutentha kwake akangolowa mu pampu. Osati kutentha. Mphamvu ya madzi. Madzi aliwonse amatha kuwira kutentha kwa chipinda ngati mphamvu yatsika kwambiri, ndipo ndicho chitseko.
Pampu iliyonse ili ndi manambala awiri mwa awa. NPSH Available (NPSHA) ndi yomwe makina amapereka ku polowera pampu. NPSH Required (NPSHR) ndi yomwe pampu imafunika kuti iyende popanda madzi kung'anima kuti ikhale nthunzi mkati mwake.
Ngati madziwo apezeka pansi pa zomwe zikufunika, madziwo amayamba kuwira pa impeller. Ndiko kutsekeka kwa madzi, ndipo ndi koopsa.
Chifukwa Chake Lamulo la 3 Peresenti Kuyambira 1932 Likuyendetsabe Makampani
Apa pali gawo lomwe limadabwitsa anthu. Nambala ya NPSHR pama curve ambiri a pampu si pamene pampu imasiya kugwira ntchito. Imasonyeza pamene magwiridwe antchito atsika kale. Kuyambira 1932, Hydraulic Institute inavomereza kutsika kwa 3 peresenti mu mutu pamlingo wokhazikika wa madzi monga tanthauzo lovomerezeka, chifukwa chimenecho chinali kusintha kochepa kwambiri komwe akanatha kuyeza modalirika pa choyimilira choyesera.
Muyezo wamakampani unakhazikitsidwa pafupifupi zaka zana zapitazo kutengera zomwe zingayesedwe, osati zomwe zimateteza pampu. Pofika nthawi yomwe mudatsegula NPSHR yofalitsidwa, thovu la cavitation lakhala likugwa kale mkati mwa impeller kwa kanthawi. Sanasinthe magwiridwe antchito mokwanira kuti awonekere pa gauge.
Ichi ndichifukwa chake opanga mapulani odziwa bwino ntchito sagwira ntchito ku NPSHR. Amagwira ntchito ndi malire. Ndipo kukula kwa malire amenewo ndi komwe kumayambira mikangano yeniyeni.
Masewera a Malire
Ndiye mukufuna ndalama zingati zowonjezera? Yankho loona mtima: zimatengera zomwe mukupopa, liwiro lake, komanso mphamvu zomwe zayikidwa mu suction. Malangizo a Hydraulic Institute amapereka ziŵerengero zomwe mukufuna kuzigwiritsa ntchito m'mafakitale osiyanasiyana. Malinga ndi chidule chaposachedwa cha ANSI/HI 9.6.1, muyezowu tsopano ukukhudza magawo khumi osiyanasiyana amsika, kuphatikiza mapampu opangira mafuta, mapampu opangira mankhwala, mphamvu zamagetsi, ndi madzi otayira.
Zochepera zomwe zafalitsidwa ndi zochepa kuposa momwe anthu ambiri amaganizira. Pa ntchito zogwiritsa ntchito mphamvu zochepa monga ma towers ozizira ndi mapampu amadzi otayidwa ndi chitsulo, margin ratios olimbikitsidwa amakhala pamwamba pa 1, zomwe zikutanthauza kuti NPSHA imachotsa NPSHR pang'ono. Imamveka yopyapyala. Pa mapampu opanda mphamvu zambiri, palibe vuto.
Makina opopera mphamvu kwambiri ndi osiyana. Gulu logwira ntchito mkati mwa Hydraulic Institute lachita izi malire ofunikira Mapeto ake ndi apamwamba kwambiri mpaka kufika pa NPSHR kanayi, zomwe zikutanthauza kuti chiŵerengero cha NPSHA/NPSHR cha 1 mpaka 5. Mapeto ake ndi apamwamba kwambiri a mapampu omwe ali ndi mphamvu yothamanga kwambiri.
Pamene Malire Okha Sali Okwanira
Tsopano gawo losasangalatsa. Ngakhale phindu lalikulu silikupulumutsani nthawi zonse. Mabuku amakampani amafotokoza mapampu akuluakulu operekera chakudya cha boiler omwe adapangidwa ndi NPSHA pafupifupi kawiri kuposa NPSHR yofalitsidwa, kupitirira zomwe deta imafuna.
Ma impeller oyamba, opangidwa ndi chitsulo chosapanga dzimbiri cha CA6NM, adatengabe chaka chimodzi chokha asanawonongedwe ndi cavitation. Kuwirikiza kawiri malire omwe buku la malangizo lidapempha, ndipo pampuyo inkadzitafuna yokha pachaka.
Maphunziro ngati amenewo ndi chifukwa chake opanga ena amatchula njira ina yomwe nthawi zina imalembedwa kuti NPSH yokhala ndi subscript ya nthawi yayitali. Kukwaniritsa mtengo umenewo ndipo wogulitsa akutsimikizira kuti palibe kutayika kwa magwiridwe antchito kapena kusintha kwa ziwalo mkati mwa zaka zambiri zogwira ntchito mosalekeza. Ndi njira yosiyana yonena kuti nambala ya datasheet sidzakutetezani, koma iyi idzakutetezani.
Kodi Izi Zikutanthauza Chiyani Ngati Mukugula, Kufotokozera, Kapena Kungofuna Kudziwa?
Simukuyenera kukhala mainjiniya wa zida zozungulira kuti mutengepo kanthu kothandiza pa izi.
Mfundo zingapo zimatidabwitsa kwambiri:
- Chitani NPSHR ngati malo, osati chandamale. Ngati lingaliro likuwonetsa kuti NPSHA ili pamwamba pa NPSHR, ndiye kuti ndi chizindikiro chofiira, osati kuvomerezedwa. Funsani momveka bwino za malire.
- Funsani za mphamvu yokoka. Mapampu awiri omwe ali ndi ma NPSHR ofanana amatha kuchita zinthu mosiyana kwambiri pansi pa malire omwewo. Mphamvu yoyamwa kwambiri imafuna malo ambiri ogwirira ntchito.
- Yang'anani malangizo okhudza kugwiritsa ntchito. Mphepete mwa malo ozizira ndi abwino kwambiri pa nsanja yoziziritsira madzi ingakhale yoopsa pa chakudya cha boiler. Gawo la msika ndi lofunika kwambiri kuposa lamulo wamba.
- Yang'anani malo ogwirira ntchito. Pampu yomwe ikuyenda kutali ndi malo ake abwino kwambiri imachita zinthu moyipa kuposa momwe deta imanenera, ndipo NPSHR yokha imakwera mmwamba kwambiri.
- Bajeti yoti iwonetsedwe. Kuwonongeka kwa cavitation kumaonekera pa ma impeller vanes kale kwambiri kusanaonekere pa kuchuluka kwa madzi omwe akuyenda. Ngati mudikira kuti pressure gauge ikudziwitseni, impelleryo ndi yotayika kale.
Palibe chilichonse mwa izi chomwe ndi chidziwitso chachilendo. Ndi kusiyana pakati pa pampu yomwe imayenda bwino kwa zaka khumi ndi yomwe imakhala chinthu chobwerezabwereza pa bajeti yokonza. Nambala yobisika pa datasheet imasankha yomwe mupeza.