Electromagnetic cov ntxaij vab tshaus tau dav siv hauv kev lag luam. Lawv pab tshem tawm cov teeb meem cuam tshuam ntawm qee lub ntsiab lus ntawm cov khoom siv hluav taws xob rau lwm tus, los tiv thaiv cov neeg ua haujlwm thiab cov khoom siv los ntawm kev cuam tshuam ntawm sab nraud uas tshwm sim thaum lub sijhawm ua haujlwm ntawm lwm yam khoom siv. Lub "quenching" ntawm sab nraud magnetic teb yog tsim nyog nyob rau hauv lub creation ntawm lub chaw soj nstuam npaj rau kev hloov thiab kev ntsuam xyuas ntawm cov khoom rhiab heev. Nws kuj tseem yuav tsum tau muaj nyob rau hauv cov tshuaj thiab cov cheeb tsam ntawm kev tshawb fawb uas ntsuas cov teb nrog ultra-low induction yog nqa tawm; los tiv thaiv cov ntaub ntawv thaum nws kis tau tus kab mob.
Methods
Kev tiv thaiv kev sib nqus sib nqus yog txheej txheej los txo lub zog ntawm qhov tsis tu ncua lossis hloov pauv hauv ib qho chaw ntawm qhov chaw. Ib qho chaw sib nqus, tsis zoo li qhov hluav taws xob, tsis tuaj yeem ua kom tsis muaj zog tag nrho.
Hauv kev lag luam, cov chaw tsis muaj zog los ntawm kev hloov pauv, cov hlau nplaum ruaj khov, kev teeb tsa siab tam sim no thiab cov khoom siv hluav taws xob muaj qhov cuam tshuam loj tshaj plaws. Lawv tuaj yeem cuam tshuam tag nrho kev ua haujlwm ntawm cov khoom siv nyob sib ze.
Ntaus siv 2txoj kev tiv thaiv:
- Kev siv cov ntxaij vab tshaus ua los ntawm superconducting lossis ferromagnetic cov ntaub ntawv. Qhov no ua tau zoo nyob rau hauv lub xub ntiag ntawm qhov tsis tu ncua lossis tsawg zaus magnetic teb.
- Txoj kev them nyiaj (eddy tam sim no damping). Eddy tam sim no yog cov hluav taws xob tam sim no uas tshwm sim hauv tus neeg xyuas pib thaum cov hlau nplaum hloov pauv. Txoj kev no qhia tau hais tias cov txiaj ntsig zoo tshaj plaws rau cov teb ntau zaus.
Principles
Cov ntsiab cai ntawm kev tiv thaiv cov hlau nplaum yog raws li cov qauv ntawm kev nthuav tawm ntawm cov hlau nplaum hauv qhov chaw. Raws li, rau txhua txoj hauv kev tau teev tseg saum toj no, lawv yog raws li hauv qab no:
- Yog tias koj tso lub inductor rau hauv lub casing ua los ntawm ferromagnet, ces cov kab ntawm induction ntawm sab nraud magnetic teb yuav dhau mus rau ntawm phab ntsa ntawm lub vijtsam tiv thaiv, vim nws muaj qhov sib nqus tsawg dua piv rau qhov chaw hauv nws.. Cov kab ntawm cov quab yuam uas raug ntxias los ntawm lub kauj nws tus kheej kuj yuav luag tag nrho raug kaw rau cov phab ntsa ntawm lub casing. Rau qhov kev tiv thaiv zoo tshaj plaws nyob rau hauv cov ntaub ntawv no, nws yog ib qho tsim nyog yuav tau xaiv cov ntaub ntawv ferromagnetic uas muaj qhov sib nqus permeability siab. Hauv kev xyaum, hlau alloys feem ntau yog siv. Txhawm rau ua kom muaj kev ntseeg siab ntawm qhov screen, nws yog ua los ntawm tuab-walled los yog prefabricated los ntawm ob peb casings. Qhov tsis zoo ntawm qhov kev tsim no yog nws qhov hnyav, qhov hnyav thiab qhov tsis zoo ntawm kev tiv thaiv nyob rau hauv lub xub ntiag ntawm seams thiab txiav nyob rau hauv cov phab ntsa ntawm lub casing.
- Nyob rau hauv txoj kev thib ob, qhov tsis muaj zog ntawm cov hlau nplaum sab nraudtshwm sim los ntawm qhov kev txiav txim ntawm lwm qhov chaw rau nws, induced los ntawm lub nplhaib eddy tam sim no. Nws cov kev taw qhia yog opposite rau cov kab induction ntawm thawj daim teb. Raws li qhov zaus nce, lub attenuation yuav hais tau ntau dua. Nyob rau hauv cov ntaub ntawv no, daim hlau nyob rau hauv daim ntawv ntawm ib lub nplhaib ntawm conductors nrog tsawg resistivity yog siv rau shielding. Lub thawv zoo li lub tog raj kheej ua los ntawm tooj liab lossis txhuas feem ntau yog siv los ua cov npo-casings.
Key Features
Muaj 3 yam tseem ceeb los piav txog cov txheej txheem tiv thaiv:
- Sib npaug sib nqus teb qhov tob tob. Yog li cia peb mus ntxiv. Daim duab no yog siv los soj ntsuam cov nyhuv ntawm eddy tam sim no. Qhov me me ntawm nws tus nqi, qhov siab dua qhov tam sim no ntws hauv cov txheej txheej ntawm cov khoom tiv thaiv. Raws li, qhov ntau dua qhov magnetic teb induced los ntawm nws, uas displaces sab nraud. Qhov sib npaug qhov tob yog txiav txim los ntawm cov qauv hauv qab no. Nyob rau hauv cov qauv no, ρ thiab Μ ryog cov resistivity thiab txheeb ze sib nqus permeability ntawm cov khoom siv tshuaj ntsuam, ntsig txog (cov chav ntsuas ntawm thawj tus nqi yog Ohm∙m); f yog qhov zaus ntawm daim teb, ntsuas hauv MHz.
- Shielding efficiency e - qhov piv ntawm cov hlau nplaum lub zog nyob rau hauv lub shielded qhov chaw nyob rau hauv tsis muaj thiab muaj ntawm daim thaiv. Tus nqi no yog qhov siab dua, qhov ntau dua qhov tuab ntawm qhov screen thiab qhov sib nqus permeability ntawm nws cov khoom. Sib nqus permeability yog ib qho cim qhia tias muaj pes tsawg zaus qhov induction hauv ib yam khoomtxawv ntawm qhov hauv lub tshuab nqus tsev.
- Txo ntawm qhov sib nqus lub zog thiab eddy tam sim no ceev ntawm qhov tob x ntawm qhov chaw tiv thaiv. Qhov ntsuas tau suav nrog cov qauv hauv qab no. Ntawm no A0 yog tus nqi ntawm qhov screen, x0 yog qhov tob uas qhov kev siv zog lossis qhov ceev tam sim no txo e zaug.
Screen designs
Kev tiv thaiv npog tiv thaiv cov hlau nplaum tuaj yeem ua rau ntau yam qauv:
- daim ntawv thiab loj heev;
- nyob rau hauv daim ntawv ntawm cov hlab hollow thiab casings nrog ib tug cylindrical los yog rectangular seem;
- ib txheej thiab ntau txheej, nrog rau qhov sib txawv ntawm huab cua.
Vim tias kev suav ntawm cov txheej txheem yog qhov nyuaj, qhov txiaj ntsig no feem ntau xaiv los ntawm cov ntawv siv, raws li kev tiv thaiv kev ua haujlwm nkhaus uas tau txais kev sim. Txiav thiab seams nyob rau hauv lub thawv yog tso cai ua raws li cov kab ntawm eddy tam sim no. Txwv tsis pub, cov nyhuv thaiv yuav raug txo.
Hauv kev xyaum, nws yog ib qho nyuaj kom tau txais kev tiv thaiv siab, vim nws yog ib txwm tsim nyog los ua qhov rau cable nkag, qhov cua thiab kev saib xyuas ntawm kev teeb tsa. Rau cov coils, seamless casings yog ua los ntawm cov ntawv extrusion txoj kev, thiab hauv qab ntawm lub cylindrical screen ua ib tug tshem tau cover.
Tsis tas li ntawd, thaum cov txheej txheem tsim los rau hauv kev sib cuag, cov kab nrib pleb vim yog qhov tsis sib xws. Txhawm rau tshem tawm lawv, sivmechanical clamps lossis gaskets ua los ntawm cov khoom siv hluav taws xob. Lawv muaj nyob rau hauv ntau qhov sib txawv thiab nrog cov khoom sib txawv.
Eddy tam sim no yog cov tam sim no uas tsis tshua muaj kev ncig, tab sis lawv muaj peev xwm tiv thaiv kev nkag mus ntawm cov hlau nplaum los ntawm qhov screen. Nyob rau hauv lub xub ntiag ntawm ntau lub qhov nyob rau hauv lub casing, qhov txo nyob rau hauv lub shielding coefficient tshwm sim raws li ib tug logarithmic dependence. Nws tus nqi tsawg tshaj plaws yog pom nrog cov thev naus laus zis ntawm qhov loj. Yog li ntawd, nws raug pom zoo kom tsim ob peb qhov me me es tsis yog ib qho loj. Yog tias tsim nyog los siv qhov ntsuas tus qauv (rau cable nkag thiab lwm yam kev xav tau), ces siv transcendental waveguides.
Nyob rau hauv qhov chaw magnetostatic tsim los ntawm cov hluav taws xob ncaj qha, lub vijtsam txoj haujlwm yog kom tshem tawm cov kab teb. Cov khoom tiv thaiv yog ntsia ze li sai tau rau qhov chaw. Grounding tsis tas yuav tsum tau. Kev tiv thaiv zoo nyob ntawm qhov sib nqus permeability thiab thickness ntawm cov ntaub thaiv npog. Raws li yav tas los, steels, permalloy thiab sib nqus alloys nrog siab sib nqus permeability yog siv.
Shielding ntawm cable txoj kev yog tsuas yog ua los ntawm ob txoj kev - siv cables nrog shielded los yog tiv thaiv twisted khub thiab nteg conduits nyob rau hauv aluminium thawv (los yog inserts).
superconductive screens
Kev ua haujlwm ntawm cov ntxaij vab tshaus magnetic superconducting yog raws li cov nyhuv Meissner. Qhov tshwm sim no muaj nyob rau hauv qhov tseeb hais tias lub cev nyob rau hauv ib tug magnetic teb mus rau hauv ib tug superconducting xeev. Nyob rau tib lub sijhawm, cov hlau nplaumLub permeability ntawm lub casing yuav sib npaug zos rau xoom, uas yog, nws tsis dhau lub magnetic teb. Nws tau them tag nrho hauv qhov ntim ntawm lub cev muab.
Qhov kom zoo dua ntawm cov ntsiab lus no yog tias lawv ua haujlwm tau zoo dua, kev tiv thaiv los ntawm lwm qhov chaw sib nqus tsis nyob ntawm qhov zaus, thiab cov txiaj ntsig them nyiaj tuaj yeem ua rau lub sijhawm ntev. Txawm li cas los xij, hauv kev xyaum, cov nyhuv Meissner tsis tiav, vim tias hauv cov ntxaij vab tshaus tiag tiag ua los ntawm cov khoom siv superconducting yeej ib txwm muaj cov txheej txheem tsis sib xws uas ua rau muaj qhov sib nqus flux ntxiab. Cov nyhuv no yog qhov teeb meem loj rau kev tsim cov casings txhawm rau tiv thaiv cov hlau nplaum. Lub magnetic teb attenuation coefficient yog qhov ntau dua, qhov siab dua cov tshuaj purity ntawm cov khoom. Hauv kev sim, qhov ua tau zoo tshaj plaws tau sau tseg rau txhuas.
Lwm qhov tsis zoo ntawm superconducting magnetic teb shielding cov ntaub ntawv yog:
- tus nqi siab;
- presence of residual magnetic field;
- tshwm sim ntawm lub xeev ntawm superconductivity tsuas yog thaum qhov kub thiab txias;
- tsis muaj peev xwm ua haujlwm hauv cov hlau nplaum siab.
khoom
Feem ntau, cov ntxaij vab tshaus carbon steel yog siv los tiv thaiv qhov chaw sib nqus, vim tias lawv tuaj yeem hloov tau yooj yim rau vuam, vuam, pheej yig thiab muaj kev tiv thaiv corrosion zoo. Ntxiv rau lawv, cov ntaub ntawv xws li:
- txuj ci aluminium ntawv ci;
- mos magnetic alloy ntawm hlau, aluminium thiab silicon (alsifer);
- tooj;
- conductive coated iav;
- zinc;
- transformer steel;
- cov khoom enamels thiab cov kua roj vanish;
- brass;
- metallized fabrics.
Cov qauv tsim, lawv tuaj yeem ua rau hauv daim ntawv ntawm cov nplooj ntawv, nets thiab ntawv ci. Cov ntaub ntawv muab kev tiv thaiv zoo dua, thiab cov ntaub ntawv mesh yooj yim dua rau kev sib sau - lawv tuaj yeem koom ua ke los ntawm qhov chaw vuam hauv 10-15 mm increments. Txhawm rau kom muaj kev tiv thaiv corrosion, daim phiaj yog varnished.
Cov lus pom zoo rau kev xaiv cov khoom
Thaum xaiv cov khoom siv rau kev tiv thaiv cov ntxaij vab tshaus, cov lus pom zoo hauv qab no tau qhia:
- Hauv cov teb tsis muaj zog, cov hlau nplaum nrog cov hlau nplaum permeability yog siv. Cov thev naus laus zis tshaj plaws yog permalloy, uas qiv nws tus kheej zoo rau kev siab thiab txiav. Lub zog magnetic teb xav tau rau nws ua tiav demagnetization, nrog rau cov hluav taws xob tiv thaiv, nyob ntawm qhov feem pua ntawm cov npib tsib xee. Los ntawm tus nqi ntawm cov khoom no, tsawg-nickel (txog 50%) thiab high-nickel (txog 80%) permalloys yog qhov txawv.
- Txhim txo lub zog poob hauv qhov chaw sib nqus sib nqus, cov casings tau muab tso rau ntawm ib tus neeg xyuas pib zoo lossis los ntawm ib qho insulator.
- Rau thaj tsam ntau dua 10 MHz, nyiaj lossis tooj liab zaj duab xis txheej nrog lub thickness ntawm 0.1 hli lossis ntau dua (cov ntxaij vab tshaus ua los ntawm cov ntawv ci-coated getinaks thiab lwm yam ntaub ntawv insulating), nrog rau tooj liab, txhuas, thiab tooj dag, muab cov nyhuv zoo. Txhawm rau tiv thaiv tooj liab los ntawm oxidation, nws yog coated nrog nyiaj.
- Thicknesscov khoom nyob ntawm qhov zaus f. Qhov qis f, qhov ntau dua qhov tuab yuav tsum ua kom tiav cov nyhuv shielding tib yam. Ntawm qhov siab zaus, rau kev tsim cov casings los ntawm txhua yam khoom, lub thickness ntawm 0.5-1.5 hli yog txaus.
- Rau cov teb uas muaj siab f, ferromagnets tsis siv, vim lawv muaj kev tiv thaiv siab thiab ua rau muaj zog loj. Cov khoom siv hluav taws xob ntau dua li cov hlau yuav tsum tsis txhob siv los tiv thaiv cov hlau nplaum ruaj khov.
- Rau kev tiv thaiv ntau qhov dav, cov ntaub ntawv ntau txheej (steel nplooj ntawv nrog cov txheej txheem hlau zoo heev) yog cov tshuaj zoo tshaj.
Txoj cai xaiv dav dav yog raws li hauv qab no:
- High frequencies yog cov khoom siv hluav taws xob zoo heev.
- Tsawg zaus yog cov khoom siv nrog siab sib nqus permeability. Kev tshuaj xyuas hauv qhov no yog ib txoj haujlwm nyuaj tshaj plaws, vim nws ua rau kev tsim ntawm lub vijtsam tiv thaiv hnyav dua thiab nyuaj.
Cov ntaub nplaum
Cov ntaub thaiv npog npog yog siv rau cov laj thawj hauv qab no:
- Shielding broadband electromagnetic cuam tshuam. Feem ntau lawv yog siv rau lub qhov rooj thiab phab ntsa ntawm cov khoom siv hluav taws xob, nrog rau kev tsim cov tshuaj ntsuam nyob ib puag ncig cov ntsiab lus (solenoids, relays) thiab cables.
- Tshem tawm cov nqi hluav taws xob zoo li qub uas khaws cia ntawm cov khoom siv uas muaj cov khoom siv hluav taws xob thiab cov kab hluav taws xob cathode, nrog rau hauv cov khoom siv siv los nkag / tawm cov ntaub ntawv los ntawmcomputer.
- Raws li ib feem ntawm hauv av circuits.
- Txhim txo electrostatic cuam tshuam ntawm transformer windings.
Txoj kev tsim qauv, lawv yog raws li cov khoom siv nplaum nplaum (acrylic resin) thiab ntawv ci (nrog corrugated lossis du nto) ua los ntawm cov hlau hauv qab no:
- aluminium;
- tooj;
- tinned tooj liab (rau soldering thiab zoo dua tiv thaiv corrosion).
khoom siv polymer
Hauv cov khoom siv uas, nrog rau kev tiv thaiv ntawm cov hlau nplaum, kev tiv thaiv kev puas tsuaj thiab kev poob siab yuav tsum tau siv, cov ntaub ntawv polymeric yog siv. Lawv yog tsim nyob rau hauv daim ntawv ntawm polyurethane ua npuas ncauj npog nrog ib tug polyester zaj duab xis, raws li ib tug acrylic nplaum.
Hauv kev tsim cov kua siv lead ua kua, cov khoom siv acrylic ua los ntawm cov ntaub ntawv siv tau. Nyob rau hauv txheej ntawm acrylic nplaum yog peb-dimensional conductive matrix ua los ntawm conductive hais. Vim nws elasticity, cov khoom no kuj zoo absorbs mechanical stress.
Kev them nyiaj txoj kev
Lub hauv paus ntsiab lus ntawm kev them nyiaj tiv thaiv txoj hauv kev yog los tsim ib qho chaw sib nqus uas tau coj mus rau sab nraud. Qhov no feem ntau ua tiav nrog Helmholtz coil system. Nws muaj 2 zoo tib yam nyias coils nyob coaxially ntawm qhov deb ntawm lawv lub vojvoog. Hluav taws xob tau dhau los ntawm lawv. Lub magnetic teb induced los ntawm coils yog heev uniform.
Shielding taukuj tsim los ntawm plasma. Qhov tshwm sim no raug coj mus rau hauv tus account hauv kev faib tawm ntawm cov hlau nplaum hauv qhov chaw.
kab thaiv kab
Kev tiv thaiv kev sib nqus yog qhov tseem ceeb thaum tso cov cables. Cov hluav taws xob hluav taws xob cuam tshuam rau hauv lawv tuaj yeem tshwm sim los ntawm kev suav nrog cov khoom siv hauv tsev hauv chav (cua txias, fluorescent teeb, xov tooj), nrog rau cov elevator hauv mines. Cov xwm txheej no muaj kev cuam tshuam tshwj xeeb rau cov kev sib txuas lus digital uas ua haujlwm ntawm cov txheej txheem nrog ntau zaus band. Qhov no yog vim qhov sib txawv me me ntawm lub zog ntawm cov teeb liab muaj txiaj ntsig thiab lub suab nrov nyob rau sab sauv ntawm lub spectrum. Tsis tas li ntawd, lub zog hluav taws xob hluav taws xob tawm los ntawm cov kab hluav taws xob cuam tshuam rau kev noj qab haus huv ntawm cov neeg ua haujlwm hauv thaj chaw.
Kev sib tham tshwm sim ntawm ob khub ntawm cov xov hlau vim muaj cov capacitive thiab inductive coupling ntawm lawv. Lub zog hluav taws xob hluav taws xob ntawm cov cables kuj tseem cuam tshuam vim qhov tsis sib xws ntawm lawv cov yoj impedance thiab tsis muaj zog nyob rau hauv daim ntawv ntawm tshav kub poob. Raws li qhov tshwm sim ntawm attenuation, lub teeb liab lub zog ntawm qhov kawg ntawm cov kab ntev poob ntau pua zaus.
Tam sim no, 3 txoj hauv kev tiv thaiv kab hluav taws xob tau xyaum hauv kev lag luam hluav taws xob:
- Kev siv tag nrho cov thawv hlau (steel lossis aluminium) lossis kev teeb tsa cov hlau ntxig rau hauv cov yas. Raws li lub teb zaus nce, qhov kev tshuaj ntsuam muaj peev xwm ntawm aluminium txo. Qhov tsis zoo kuj yog tus nqi siab ntawm cov thawv. Rau ntev cable khiav muajqhov teeb meem ntawm kev ua kom cov hluav taws xob tiv tauj ntawm tus kheej cov ntsiab lus thiab lawv cov hauv av kom ntseeg tau tias xoom lub peev xwm ntawm lub thawv.
- Siv cov kab thaiv thaiv. Txoj kev no muab kev tiv thaiv siab tshaj plaws raws li cov ntaub qhwv ib ncig ntawm lub cable nws tus kheej.
- Nqus deposition ntawm hlau ntawm PVC channel. Txoj kev no tsis muaj txiaj ntsig ntawm cov zaus mus txog 200 MHz. Qhov "quenching" ntawm qhov chaw sib nqus yog kaum npaug tsawg dua piv rau kev tso cov kab hauv cov thawv hlau vim muaj kev tiv thaiv siab.
Nyob ntawm cables
Muaj 2 hom thaiv kab thaiv:
- Nrog ib qho screen. Nws yog nyob ib ncig ntawm cov uas tsis muaj kev tiv thaiv stranded conductors. Qhov tsis zoo ntawm cov cables no yog tias muaj qhov sib tw loj (5-10 npaug ntau dua li cov ntawv thaiv), tshwj xeeb ntawm cov khub nrog tib lub suab sib tw.
- Cables nrog shielded twisted khub. Tag nrho cov khub yog tiv thaiv tus kheej. Vim lawv cov nqi siab dua, lawv feem ntau yog siv hauv cov tes hauj lwm nrog cov kev xav tau kev nyab xeeb nruj thiab hauv cov chav nrog ib puag ncig nyuaj electromagnetic. Kev siv cov cables zoo li no hauv kev sib txuas ua ke ua rau nws tuaj yeem txo qhov kev ncua deb ntawm lawv. Qhov no txo cov nqi piv rau kev sib cais.
Twisted-pair shielded cable yog ib khub insulated ntawm conductors (lawv tus lej feem ntau yog los ntawm 2 txog 8). Qhov kev tsim no txo cov crosstalk.nruab nrab ntawm conductors. Unshielded khub tsis muaj qhov yuav tsum tau ua hauv av, lawv muaj qhov yooj yim dua, me dua qhov ntev, thiab yooj yim ntawm kev teeb tsa. Cov khub shielded muab kev tiv thaiv tiv thaiv electromagnetic cuam tshuam thiab zoo cov ntaub ntawv xa mus rau tes hauj lwm.
Cov ntaub ntawv xov xwm kuj tseem siv ob txheej thaiv thaiv, uas muaj kev tiv thaiv ntawm kev sib tw twist hauv daim ntawv ntawm cov ntaub ntawv yas lossis cov ntawv ci, thiab cov hlau sib txuas. Txhawm rau tiv thaiv cov hlau nplaum zoo, cov kab hluav taws xob zoo li no yuav tsum tau ua kom zoo.
