Thaum lub sijhawm ua haujlwm ntawm cais case cov twj tso kua mis, kev vibrations tsis tuaj yeem tsis xav tau, vim tias kev vibrations tsis yog tsuas yog pov tseg cov peev txheej thiab lub zog, tab sis kuj tsim cov suab nrov tsis tsim nyog, thiab tseem ua rau lub twj tso kua mis puas, uas tuaj yeem ua rau muaj xwm txheej loj thiab kev puas tsuaj. Kev vibrations feem ntau tshwm sim los ntawm cov laj thawj hauv qab no.

1. Cavitation

Cavitation feem ntau tsim random siab zaus broadband zog, qee zaum superimposed nrog cov hniav hla zaus harmonics (ntau ntau). Cavitation yog ib qho tsos mob ntawm qhov tsis txaus net positive suction head (NPSH). Thaum cov kua twj tso kua mis ntws los ntawm qee qhov chaw hauv cheeb tsam ntawm qhov chaw ntws los ntawm qee qhov laj thawj, qhov siab ntawm cov kua txo qis mus rau qhov nqus vapor siab (vaporization siab) ntawm cov kua ntawm qhov ntsuas kub, cov kua vaporizes ntawm no, tsim cov pa, npuas. raug tsim; Nyob rau tib lub sijhawm, cov roj yaj hauv cov kua kuj tseem yuav ua rau hauv daim ntawv ntawm cov npuas, ua rau ob theem ntws hauv ib cheeb tsam. Thaum cov npuas txav mus rau qhov chaw siab, cov kua dej siab nyob ib ncig ntawm lub npuas yuav nrawm nrawm, ntsws thiab tawg npuas. Thaum lub sij hawm thaum lub npuas condenses, shrinks, thiab tawg, cov kua nyob ib ncig ntawm lub npuas yuav sau cov kab noj hniav (tsim los ntawm cov condensation thiab rupture) ntawm kev kub ceev, tsim ib tug muaj zog shock yoj. Cov txheej txheem ntawm kev tsim cov npuas thiab tawg ntawm cov npuas ua kom puas cov khoom ntws-dhau yog cov txheej txheem cavitation ntawm lub twj tso kua mis. Lub cev qhuav dej ntawm cov npuas npuas tuaj yeem ua rau puas tsuaj thiab tuaj yeem ua rau lub twj tso kua mis thiab impeller puas. Thaum cavitation tshwm sim hauv lub twj tso kua mis sib cais, nws suab zoo li "marbles" lossis "gravel" tau dhau los ntawm lub twj tso kua mis. Tsuas yog thaum qhov xav tau NPSH ntawm lub twj tso kua mis (NPSHR) qis dua NPSH ntawm lub cuab yeej (NPSHA) tuaj yeem zam qhov cavitation.

2. Pump flow pulsation

Pump pulsation yog ib qho mob uas tshwm sim thaum lub twj tso kua mis ua haujlwm ze nws lub taub hau kaw. Lub vibrations nyob rau hauv lub sij hawm waveform yuav yog sinusoidal. Tsis tas li ntawd, cov spectrum tseem yuav tau tswj hwm los ntawm 1X RPM thiab cov hniav hla dhau zaus. Txawm li cas los xij, cov peaks no yuav ua tsis raug, nce thiab txo qis raws li cov dej ntws tshwm sim. Lub ntsuas ntsuas ntawm lub twj tso kua mis qhov hluav taws xob yuav hloov pauv mus thiab nqis. Yog tiassplit case twj tso kua misLub qhov hluav taws xob muaj lub viav vias kos valve, lub valve caj npab thiab lub qhov hnyav yuav thaws rov qab los, qhia tias tsis ruaj khov.

3. Lub twj tso kua mis yog khoov

Qhov teeb meem ntawm lub tog raj kheej ua rau lub siab axial vibration, nrog axial theem sib txawv tending mus rau 180 ° ntawm tib rotor. Yog tias qhov khoov nyob ze ntawm qhov nruab nrab ntawm tus ncej, qhov tseem ceeb vibration feem ntau tshwm sim ntawm 1X RPM; tab sis yog tias qhov khoov nyob ze ntawm qhov sib txuas, qhov tseem ceeb ntawm kev vibration tshwm sim ntawm 2X RPM. Nws yog qhov ntau dua rau lub twj tso kua mis kom khoov ntawm lossis ze ntawm qhov sib txuas. Lub dial gauge tuaj yeem siv los xyuas kom meej tias ncej deflection.

4. Lub twj tso kua mis impeller tsis sib npaug

Split case twj impellers yuav tsum muaj qhov sib npaug ntawm cov twj tso kua mis thawj zaug. Qhov no yog qhov tseem ceeb tshwj xeeb tshaj yog vim hais tias lub zog los ntawm qhov tsis sib xws tuaj yeem cuam tshuam rau lub neej ntawm lub twj tso kua mis bearings (cov kabmob lub neej yog inversely proportional rau lub voos xwmfab ntawm cov ntaub ntawv dynamic load). Cov twj tso kua mis yuav muaj qhov nruab nrab dai lossis cantilevered impellers. Yog hais tias lub impeller yog nruab nrab-dhau, lub zog tsis sib npaug feem ntau tshaj ob peb qhov tsis sib xws. Hauv qhov no, qhov siab tshaj vibrations feem ntau yog nyob rau hauv radial (kab rov tav thiab ntsug) kev taw qhia. Qhov siab tshaj plaws amplitude yuav nyob ntawm qhov khiav ceev ntawm lub twj tso kua mis (1X RPM). Nyob rau hauv cov ntaub ntawv ntawm ib tug quab yuam imbalance, lub kab rov tav lateral thiab nruab nrab theem yuav yog kwv yees li qub (+/- 30 °) raws li cov theem ntsug. Tsis tas li ntawd, cov theem kab rov tav thiab ntsug ntawm txhua lub twj tso kua mis feem ntau sib txawv li ntawm 90 ° (+/- 30 °). Los ntawm nws tus qauv tsim, lub nruab nrab-tshem tawm impeller muaj qhov sib npaug axial quab yuam ntawm sab hauv thiab sab nraud bearings. Qhov siab axial vibration yog qhov qhia tau tias lub twj tso kua mis impeller raug thaiv los ntawm cov khoom txawv teb chaws, ua rau axial vibration feem ntau nce ntawm kev khiav hauj lwm ceev. Yog tias lub twj tso kua mis muaj lub impeller cantilevered, qhov no feem ntau ua rau muaj qhov siab tshaj axial thiab radial 1X RPM. Axial nyeem ntawv zoo li nyob rau hauv-theem thiab ruaj khov, thaum cantilevered rotors nrog radial theem nyeem ntawv uas tej zaum yuav tsis ruaj khov muaj ob lub zog thiab ob peb qhov tsis sib xws, txhua qhov yuav tsum tau kho. Yog li ntawd, kev hloov kho qhov hnyav feem ntau yuav tsum tau muab tso rau ntawm 2 lub dav hlau los tiv thaiv lub zog thiab ob peb qhov tsis sib xws. Nyob rau hauv cov ntaub ntawv no nws yog feem ntau yuav tsum tau tshem tawm lub twj tso kua mis rotor thiab muab tso rau ntawm ib lub tshuab ntsuas kom sib npaug kom txaus txaus raws li 2 lub dav hlau feem ntau tsis tuaj yeem nkag mus rau ntawm qhov chaw siv.

5. Pump ncej misalignment

Shaft misalignment yog ib yam mob nyob rau hauv ib tug ncaj tsav twj tso kua mis qhov twg lub centerlines ntawm ob txuas shafts tsis coincide. Parallel misalignment yog rooj plaub uas qhov chaw nruab nrab ntawm cov shafts yog parallel tab sis offset los ntawm ib leeg. Lub vibration spectrum feem ntau yuav qhia 1X, 2X, 3X ... siab, thiab nyob rau hauv cov xwm txheej hnyav, ntau zaus harmonics yuav tshwm sim. Nyob rau hauv lub radial kev taw qhia, lub coupling theem Qhov txawv yog 180 °. Angular misalignment yuav qhia siab axial 1X, qee qhov 2X thiab 3X, 180 ° theem tawm ntawm theem ntawm ob qhov kawg ntawm kev sib txuas.

6. Pump bearing teeb meem

Peaks ntawm non-synchronous zaus (nrog rau harmonics) yog cov tsos mob ntawm dov bearing hnav. Lub neej luv luv nyob rau hauv cov ntaub ntawv sib cais cov twj tso kua mis feem ntau yog qhov tshwm sim ntawm kev xaiv cov kabmob tsis zoo rau daim ntawv thov, xws li kev thauj khoom ntau, lubrication tsis zoo lossis kub kub. Yog tias hom kabmob thiab cov chaw tsim khoom paub, qhov tshwj xeeb ntawm qhov tsis ua haujlwm ntawm lub nplhaib sab nraud, lub nplhaib sab hauv, cov khoom dov thiab lub tawb tuaj yeem txiav txim siab. Cov kev ua tsis tiav no rau hom kabmob no tuaj yeem pom nyob rau hauv cov rooj hauv feem ntau kev saib xyuas (PdM) software niaj hnub no.