Vanhu pavanofungidzira michina yemumaindasitiri ichikundikana, vanofungidzira mabheringi akasakara, mamota akatsva, kana chisimbiso chakazopera. Mainjiniya emafekitori vanoziva kuti kazhinji hazviwanzoitiki. Pombi inogona kuva itsva, yakakura zvakanaka, uye ichizvidya yoga mukati megore nekuda kwenhamba imwe chete isinganzwisiswi zvakanaka papepa redata.
Nhamba iyoyo inonzi NPSH. Kana usati wamboshanda nemapombi, zvinonzwika semuto wemavara. Asi pfungwa iri shure kwayo inotsanangura chikamu chikuru chekutadza kwakavanzika kunoita kuti vatariri vezvivakwa varambe vakamuka husiku.
Saka chii ichocho, uye nei kuita zvisirizvo kuchikanganisa midziyo inodhura?
NPSH muChirungu Chisina Kujeka
Net Positive Suction Head inoyera kuti mvura ine simba rakadii pamusoro pekupisa kwayo panguva yainopinda mupombi. Kwete tembiricha. Kudzvanywa. Chero mvura inogona kufashaira pakupisa kwemukamuri kana kudzvanywa kwacho kukaderera zvakanyanya, uye ndizvo zvinokanganisa.
Pombi yega yega ine nhamba mbiri idzi. NPSH Available (NPSHA) ndiyo inounzwa nesystem kupombi inopinzwa. NPSH Required (NPSHR) ndiyo inofanirwa kufambiswa nepombi pasina mvura inopenya kuti iite utsi mukati mayo.
Kana mvura yacho ikadonha pasi pezvinodiwa, mvura yacho inotanga kufashaira paimpeller. Izvozvo zvinopisa, uye zvine hutsinye.
Nei Mutemo we3 Percent kubva muna 1932 uchiri kumhanyisa indasitiri?
Heino chikamu chinokatyamadza vanhu. Nhamba yeNPSHR pamakoringi mazhinji epombi haisi iyo pombi inomira kushanda. Inoratidza iyo mashandiro atodzikira. Kubva muna 1932, Hydraulic Institute yakasarudza kudzikira kwe3 muzana mumusoro pamwero wemvura usingachinji setsananguro yepamutemo, nekuti ndiyo yaive shanduko diki yavaigona kuyera nenzira yakavimbika pachigadziko chekuyedza.
Mwero weindasitiri iyi wakagadzwa makore anoda kusvika zana apfuura zvichibva pane zvinogona kuyerwa, kwete pane zvinodzivirira pombi. Pawakazosvika paNPSHR yakaburitswa, mabubble e cavitation atove achidonha mukati me impeller kwenguva yakati. Haana kungoita kuti mashandiro awo aonekwe pageji.
Ndosaka vagadziri vane ruzivo vasingashande paNPSHR. Vanomhanya nemutengo wakaderera. Uye hukuru hwemutengo iwoyo ndipo panoitika nharo chaidzo.
Mutambo weMargin
Saka unoda marii yekuwedzera? Mhinduro yechokwadi: zvinoenderana nezvauri kupomba, kukurumidza sei, uye simba rakawanda sei rinoiswa mupombi. Gwaro reHydraulic Institute rinopa zviyero zvezvinangwa zvemaindasitiri akasiyana. Sekureva kwepfupiso yechangobva kuburitswa yeANSI/HI 9.6.1, chiyero ichi ikozvino chinosanganisira zvikamu gumi zvakasiyana zvemusika, zvinosanganisira mapombi ekugadzira peturu, mapombi ekugadzira makemikari, simba remagetsi, nemvura yakasviba.
Zviyero zvakaburitswa zvakaderera kupfuura zvinofungidzirwa nevanhu vazhinji. Pakushandisa simba shoma senge matonho ekutonhodza uye mapombi emvura yakasviba akaumbwa nesimbi, margin ratios inokurudzirwa iri pamusoro pe1 zvishoma, zvichireva kuti NPSHA haibvisi NPSHR zvakanyanya. Inonzwa seyakatetepa. Pamapombi ane simba shoma, zvakanaka.
Michina inosvuta simba rakawanda imhuka yakasiyana. Boka rinoshanda mukati meHydraulic Institute rine miganhu inokurudzirwa inosvika pakakwirira kusvika paNPSHR kane kana, zvichireva kuti chiyero cheNPSHA/NPSHR che1 kusvika ku5. Mugumo wepamusoro ndewemapombi ane simba guru.
Kana Kugara Uri Wega Kusina Kukwana
Zvino chikamu chisingafadzi. Kunyangwe mari yakawanda haigari ichikuponesa. Mabhuku eindasitiri anotsanangura mapombi makuru ekubikira akagadzirwa neNPSHA akapetwa kaviri kupfuura NPSHR yakaburitswa, kupfuura zvaidiwa nedhatabhesi.
Maimpeller edanho rekutanga, akagadzirwa nesimbi isingatsvedzi yeCA6NM, akaramba kwenguva inosvika gore rimwe chete asati akuvadzwa necavitation. Makuriro akapetwa kaviri kupfuura aikumbirwa nebhuku rekushandisa, uye pombi yakaramba ichitsenga-tsenga pagore.
Zvidzidzo zvakaita seizvi ndizvo zvinoita kuti vamwe vagadziri vataure nezveimwe nzira inonyorwa seNPSH ine subscript yenguva refu. Inosangana nemutengo iwoyo uye mutengesi anovimbisa kuti hapana kurasikirwa kwekushanda kana kutsiviwa kwezvikamu mukati memakore akawanda ekushanda kwakatarwa. Inzira yakasiyana yekutaura kuti nhamba yedatasheet haizokudzivirira, asi iyi ichakudzivirira.
Izvi Zvinorevei Kana Uri Kutenga, Kutsanangura, kana Kungoda Kuziva
Hamufanirwe kunge muri mainjiniya wemidziyo inotenderera kuti muwane chimwe chinhu chinoshanda kubva pane izvi.
Mimwe nhungamiro inopfuura zvinoshamisa:
- Bata NPSHR sepasi, kwete chinangwa. Kana chikumbiro chikaratidza kuti NPSHA iri pamusoro peNPSHR zvishoma, zvinoreva kuti hapana chikonzero chekupasa. Bvunza zvakajeka kuti chiyero chemari chakamira sei.
- Bvunza nezvesimba rekusveta. Mapombi maviri ane NPSHR yakafanana anogona kuita zvakasiyana zvachose pasi pemuganhu mumwe chete. Simba rekusveta rakawanda rinoda nzvimbo yakawanda yemusoro.
- Tsvaga gwara rinoenderana nekushandiswa kwaro. Muganho wakakodzera shongwe yekutonhodza unogona kuva nengozi kumvura inofashaira muboiler. Chikamu chemusika chinonyanya kukosha kupfuura mutemo wenguva dzose.
- Tarisa nzvimbo yekushanda. Pombi inomhanya kure nenzvimbo yayo yepamusoro inoshanda zvakanaka inoita zvakaipa kupfuura zvinofanotaurwa nepepa redata, uye NPSHR pachayo inokwira kumusoro zvakanyanya.
- Bhajeti rekuongorora. Kukuvadzwa kwe cavitation kunoratidzwa pama impeller vanes kare kare kusati kwaonekwa panhamba dzekuyerera kwemhepo. Kana ukamirira kuti pressure gauge ikuudze, impeller yatove dambarefu.
Hapana chimwe cheizvi chiri ruzivo rwechinyakare. Musiyano uripo pakati pepombi inoshanda zvakanaka kwemakore gumi neimwe inova chinhu chinogara chichidzokororwa pabhajeti yekugadzirisa. Nhamba yakavanzwa papepa redata ndiyo inosarudza kuti ndeipi yaunowana.