Yuav Ua Li Cas Qhia Txog Lub Tshuab Cua Sov rau Kev Siv Lub Tshuab Nqus Tsev?

Nyob rau hauv lub tshuab nqus tsev chamber qhov tsis muaj cua tshem tawm cov cua sov hloov mus. Thaum tshav kub kub yog pauv tsuas yog los ntawm conduction (workpiece contact) thiab hluav taws xob. Cov phaj cua sov rau lub tshuab nqus tsev yuav tsum tau tsim rau qhov kev hloov pauv hluav taws xob txawv txawv no, thiab lawv tus kheej tsis dhau los ua qhov chaw paug. Kev tsim cov phaj cua sov rau kev siv lub tshuab nqus tsev tsis yog qhov tseem ceeb, vim nws xav tau kev tswj hwm thermal, kev tawm ntawm cov ntaub ntawv, hluav taws xob feedthroughs, thiab kev nyab xeeb ntawm high voltages. Lub phaj uas ua haujlwm zoo hauv huab cua tuaj yeem overheat, outgas, lossis arc thaum muab tso rau hauv lub tshuab nqus tsev.

Thermal Management in Vacuum Systems
Yog tsis muaj convective txias lub phaj cua sov tuaj yeem ncav cuag qhov kub ntau dua li hauv huab cua rau tib lub zog hluav taws xob. Cov khoom siv hluav taws xob faus rau hauv lub phaj yuav tsum ua kom zoo -coupled rau lub phaj loj kom tsis txhob muaj cua sov hauv zos. Cov kev txhawj xeeb hauv qab no yog qhov tseem ceeb rau kev siv lub tshuab nqus tsev.

Mechanisms ntawm Kub Hloov
Kev coj ua - Txoj kev loj ntawm kev hloov cov cua sov mus rau ib qho chaw ua haujlwm hauv kev sib cuag nrog lub phaj. Kev sib cuag zoo thermal (qhov chaw tiaj tus, xaiv cov khoom siv thermal interface) yog yuav tsum tau.

Radiation - Qhov tseem ceeb tshaj phaj kub ntawm 150 degree. Radiant tshav kub kis raws li txoj cai Stefan-Boltzmann (q=εσ(Tp4−Tc4)). Qhov saum npoo emissivity (ε) ntawm lub phaj cuam tshuam rau cov cua sov ntawm cov cheeb tsam uas tsis yog - tiv tauj.

Tsis muaj convection - Tsis muaj cua txias ntawm sab nraub qaum lossis ciam teb ntawm lub phaj. Thaum tshav kub kub uas tsis xa mus rau lub workpiece yog khaws cia rau hauv lub phaj thiab nws kub nce.

Coupling ntawm phaj rau rhaub
Cov cua sov yuav tsum tau txuas mus tas li thiab txuas nrog lub phaj kom txo tau cov cua sov. Brazed los yog clamped cartridge rhaub nrog kub conductive muab tshuaj txhuam (graphite raws) yog nyiam. Cov cua sov uas siv cov cua txias ntawm lawv lub cev (qhib cov cua sov, piv txwv li) tsis tsim nyog. Ib qho tseem ceeb sib txawv yog tias lub rhaub watt ceev yuav tsum tau derated rau kev pab cuam lub tshuab nqus tsev, feem ntau 30-50% ntawm qhov uas siv rau huab cua, kom tsis txhob overheating lub cua sov sheath.

Kev ntsuas kub
Kub sensors (thermocouples lossis RTDs) yuav tsum tau muab tso rau ze li qhov ua tau rau qhov chaw ua haujlwm, nyiam dua li ntawm 2-5 hli ntawm lub ntsej muag sab saum toj. Hauv lub tshuab nqus tsev, qhov kub thiab txias tsis tuaj yeem tau txais los ntawm sab nraub qaum lossis huab cua sab nyeem ntawv. Cov pob kub muaj ntau dua yam tsis muaj qhov sib npaug ntawm qhov sib npaug thiab nws raug pom zoo kom muaj ntau lub sensors sib cais nyob ib ncig ntawm lub phaj txhawm rau txheeb xyuas lawv.

Tswj ntawm Outgassing nyob rau hauv lub tshuab nqus tsev cua sov phaj
Outgassing, tso tawm cov pa hauv nruab nrog, cov dej noo lossis cov khoom tsis haum, tsis tuaj yeem ua haujlwm hauv lub tshuab nqus tsev, tshwj xeeb tshaj yog siab lossis ultra- lub tshuab nqus tsev siab (UHV). Tag nrho cov ntaub ntawv nyob rau hauv lub tshav kub phaj los ua ke yuav tsum muaj tsawg vapor siab thiab tsawg outgassing tus nqi.

Phaj Khoom
Stainless hlau (304, 316, 316L) - Cov qauv kev xaiv rau lub tshuab nqus tsev cua sov daim hlau. Tsawg outgassing. Siab zog. Electropolishing haum rau txo qhov chaw ntawm qhov chaw thiab cov impurities.

Aluminium - Zoo rau lub tshuab nqus tsev nruab nrab (10-3 rau 10-5 Torr) yog tias ntxuav kom zoo thiab anodised. Tab sis txhuas muaj cov ntxeem tau oxide txheej uas ntxiab ya raws yog li nws yuav siv sij hawm ntev kom ci tawm.

Copper - Siv vim nws cov thermal conductivity zoo, tooj liab oxidizes thiab tej zaum yuav outgas yog tsis coated los yog nqus tsev vacuum- raug rho tawm haujlwm.

Lwm yam Polymers thiab PTFE
PTFE coatings los yog cov khoom PTFE daim hlau tau txais hauv lub tshuab nqus tsev, txawm tias yuav tsum muaj kev tuav tshwj xeeb. PTFE muaj qhov tsis txaus ntseeg tawm tom qab pib ci- tawm vim nws nqus dej tsawg heev. Txawm li cas los xij, PTFE tsis pom zoo rau UHV (qis qis dua 10-7 Torr) vim tias ua rau qeeb-gassing ntawm cov tshuaj fluorine. Rau feem ntau cov ntawv thov lub tshuab nqus tsev (10⁻³ txog 10⁻⁶ Torr) kho PTFE kom raug. Lub pre-installation ci-tawm ntawm 150-200℃rau 24-48 teev nyob rau hauv lub tshuab nqus tsev tshem tawm adsorbed gases.

Hlau rwb thaiv tsev & Adhesives
Cov hlau rwb thaiv tsev yuav tsum yog lub tshuab nqus tsev ntsuas. Cov khoom siv uas tuaj yeem siv tau yog:

PTFE (Teflon) - me ntsis outgassing tom qab ci tawm Max. kub 260 degree.

Polyimide (Kapton) - Lub tshuab nqus tsev sib raug zoo heev, ntsuas kub txog 400C, me ntsis outgassing.

PVC, polyethylene los yog nylon. Tsis tau, lawv outgas plasticizers thiab lwm yam volatiles.

Tsawg-cov epoxies outgassing (xws li EpoTek H77, Torr Seal) yuav tsum tau siv los txuas cov sensors lossis kev ruaj ntseg thaiv. Tsis txhob siv silicone-raws li cov nplaum los yog RTV sealants vim lawv tawm roj siloxanes.

Ntxuav thiab ci tawm
Txhua qhov chaw yuav tsum tau muab ntxuav nrog cov kuab tshuaj nqus tsev (acetone, isopropyl cawv) thiab sib sau ua ke hauv qhov chaw huv. Ua ntej muab lub phaj tso rau hauv qhov kev pabcuam, kev sib dhos tag nrho ci - tawm hauv lub tshuab nqus tsev ntawm 100-150℃rau 24-48 teev. Cov txheej txheem no tshem tawm cov dej thiab volatile residues tso rau ntawm qhov chaw.

Hluav taws xob Hermetic Feedthroughs
Lub hwj chim thiab sensor xov hlau yuav tsum dhau los ntawm phab ntsa ntawm lub tshuab nqus tsev vacuum yam tsis muaj to. Cov qauv hluav taws xob txuas nrog elastomer ntsaws ruaj ruaj tsis tuaj yeem siv hauv lub tshuab nqus tsev vim tias lawv tawm- roj thiab tso cai rau micro- tawm. Hermetic feedthrus yog tsim nyog.

Cov Cuab Yeej Cuab Yeej - Hom Feedthroughs
Iav-rau-hlau sealing - Ib lub iav insulator yog khi rau ib lub tsev hlau thiab tus neeg xyuas pib tus pins. Haum rau qhov kub txog li 250-400 degree, nyob ntawm seb hom iav. Feem ntau rau cov hluav taws xob hluav taws xob qis rau nruab nrab (ib theem txog li 10 A ib tus pin).

Ceramic glued mus rau ib tug hlau flange (alumina los yog beryllia). Ceramic rau hlau seals. Kev ntsuas kub siab dua (500℃+) thiab txhim kho lub tshuab nqus tsev (kua pa <1 × 10-10 atm cc / sec). Rau kev siv hluav taws xob siab lossis UHV.

Compression iav sealing - Pheej yig dua, tab sis qhov kub thiab txias tsuas yog kwv yees li 150 degree.

Number thiab Rating ntawm Feedthroughs pins
Lub tshuab nqus tsev chamber cua sov phaj specification yuav tsum qhia tus naj npawb ntawm cov hluav taws xob circuits:

Fais fab rau txhua qhov cua sov (2 xaim / cheeb tsam)

Kub sensor xov hlau (ob lub xov hlau rau ib lub thermocouple lossis RTD)

Ib tug multipin feedthrough yuav muaj ob peb pins. Txhua tus pin yuav tsum tau ntsuas rau qhov tam sim no loj dua qhov siab tshaj plaws ntawm lub tshuab cua sov tam sim no. Piv txwv li, 500 W rhaub ntawm 120 V siv 4.2 A. A 10 A feedthrough pin yuav ua.

Sab Hauv Hluav Taws Xob
Tseem ceeb: Hlau los ntawm feedthrough mus rau lub cua sov phaj nyob rau hauv lub nqus tsev vacuum chamber yuav tsum tau lub nqus tsev vacuum (PTFE los yog Kapton insulated) thiab tsis muaj kub qhov chaw. Kev ruaj ntseg kev sib txuas siv ceramic terminal blocks lossis standoffs. Tsis pub siv cov hlua yas los yog cov nplaum nplaum.

Paschen Txoj Cai (Electrical Breakdown in Vacuum)
Raws li Paschen txoj cai, qhov tawg voltage ntawm ob lub conductors nyob ntawm qhov siab thiab qhov deb. Ntawm atmospheric siab breakdown tshwm sim nyob rau hauv high voltages (kV ntau yam rau me me qhov khoob). Lub zog tawg tau txo qis heev ntawm lub tshuab nqus tsev nruab nrab (10-1 txog 10-3 Torr) - hauv qee kis mus rau ob peb puas volts rau qhov sib txawv ntawm 1 hli. Thaum lub tshuab nqus tsev siab (<10^5 Torr) the breakdown voltage increases again.

Cov kev ceev faj hauv qab no yog tsim nyog rau lub tshuab nqus tsev rhuab phaj:

Tuav kom muaj kev sib cais txaus los ntawm qhov chaw hauv av mus rau cov neeg ua haujlwm nquag (xws li cov khoom siv cua sov, cov pins feedthrough). Yam tsawg kawg ntawm 5 mm rau 240 V ac lossis 10 mm rau qhov voltage ntau dua.

Zam cov npoo ntse - Cov ntsiab lus ntse ntse tsom rau qhov hluav taws xob thiab txo qhov tawg ntawm qhov hluav taws xob. Qhov zoo tshaj plaws yog qhov sib npaug terminals, tus neeg xyuas pib txoj kev.

Nyob rau hauv cov ntaub ntawv ntawm ntev sab hauv kab, siv shielded xov hlau, grounded ntawm lub chamber feedthrough.

Ua ntej daim ntawv thov hluav taws xob tag nrho, ntsuas kev tiv thaiv hluav taws xob hauv qab lub tshuab nqus tsev.

Vacuum Design Checklist - Cov Ntawv Kub Kub
Hauv qab no yog cov ntsiab lus ntawm cov ntsiab lus tseem ceeb suav nrog hauv cov lus qhia rau lub tshuab nqus tsev cua sov phaj.

Qeb RequirementNormal Solution
Phaj khoom 316 stainless hlau, tsis tshua muaj outgassing, electropolished, cleanable
Hom rhaub Intimate coupling rau phaj; derated rau lub tshuab nqus tsev vacuumBrazed cartridge rhaub (Incoloy tsho)
Watt Density Txo kom tsis txhob overheating Tsawg dua lossis sib npaug li 5 W / cm2 (vs 8-10 W / cm2 hauv huab cua)
Kev ntsuas kub ntsuas Embedded ze rau qhov chaw ua haujlwm hom K thermocouple lossis PT100 RTD
Hlau rwb thaiv tsev PTFE (Teflon) los yog Kapton Tsawg outgassing, lub tshuab nqus tsev ntsuas
Sealants / adhesives Tsawg outgassing epoxy EpoTek H77, Torr Foob (tsis muaj silicones)
Hluav taws xob feedthroughs Hermetic, leak-tightGlass-rau-hlau los yog ceramic rau hlau
Feedthrough tam sim no ntsuam xyuas Tshaj qhov cua sov load Ntau tshaj los yog sib npaug rau 10 A ib lub hwj chim tus pin rau ib txwm 1-2 kW daim hlau
High-voltage clearance Tiv thaiv Paschen kev puas tsuaj ntau dua lossis sib npaug li 5 hli qhov sib txawv (240 V), sib npaug terminals
Pre-service bake-out Tshem tawm cov pa roj adsorbed 100-150℃hauv qab lub tshuab nqus tsev rau 24-48 teev
Cov Ntaub Ntawv Tshwj Xeeb: Radiant Heating Phaj
Hauv qee cov txheej txheem nqus tsev, lub phaj cua sov tsis yog npaj los tiv tauj lub workpiece ncaj qha. Xwb, lub phaj radiates cua sov rau lub workpiece hla ib qhov sib txawv. Hauv qhov kev teeb tsa no, lub phaj nto emissivity dhau los ua qhov tseem ceeb. Cov txheej txheem siab emissivity (xws li, dub anodize ntawm txhuas, lossis Pyromark 2500 ntawm stainless hlau) yog siv los ua kom muaj cua sov hloov pauv. Txawm li cas los xij, cov coatings yuav tsum yog lub tshuab nqus tsev sib xws thiab tsis yog outgas. Pyromark 2500, txheej txheej ceramic, feem ntau yog siv rau lub tshuab nqus tsev vacuum mus txog 600 degree.

Xaus
Nqus chamber cua sov daim hlau yuav tsum tau tsim tshwj xeeb rau kev tswj thermal thiab tswj kev sib kis. Qhov tsis muaj convective txias txhais tau hais tias cov cua sov yuav tsum tau ua tib zoo txuas rau lub phaj thiab ua haujlwm ntawm qhov txo qis watt. Outgassing yog tswj los ntawm kev xaiv cov khoom uas tsis muaj vapor-siab (stainless steel, PTFE, Kapton) thiab ua ntej kev pab cuam ci-tawm. Hermetic hluav taws xob feedthroughs (iav-rau-hlau los yog ceramic-rau-hlau) yog qhov yuav tsum tau ua kom muaj kev ncaj ncees ntawm lub chamber. Paschen txoj cai tswj hwm kev tshem tawm kom tsis txhob arcing ntawm nruab nrab lub tshuab nqus tsev. Daim ntawv thov ib puag ncig- theem nqus tsev, qhov kub thiab txias, thiab cov txheej txheem rhiab heev- hais kom meej cov qauv tsim. Lub tshuab nqus tsev cua sov uas tau teev tseg kom zoo muab kev ntseeg siab, tsis muaj paug tsis muaj cua sov hloov mus rau hauv ib puag ncig uas tsis muaj convection thiab txhua qhov kev xaiv cov khoom tseem ceeb.