Lub tshuab nqus tsev jacketed yeeb nkab
Khoom Highlight - Lub Tshuab Nqus Tsev Jack ..
- Txhim Kho Rwb Thaiv Tsev: Lub tshuab nqus tsev Jackinged yeeb nkab siv rwb thaiv tsev rwb thaiv tsev rwb thaiv tsev thev naus laus zis, muab cov khoom siv hluav taws xob zoo dua. Qhov no pab txo cov hloov cua sov thiab tswj qhov kub thiab txias nyob rau hauv cov yeeb nkab, kom ua tau zoo thiab txuag hluav taws xob.
- Txo kev ua haujlwm kub ua ntej: Nrog nws lub tshuab nqus tsev-ntim tsim, peb lub tshuab nqus tsev lub tshuab nqus dej tau txo cov dej ua kua lossis roj av. Cov yam ntxwv no tsis tsuas yog txhim kho kev ua tau zoo tag nrho tab sis kuj txo cov nqi ua haujlwm.
- Corrosion Kuj: CorraTus los ntawm cov ntaub ntawv zoo, peb lub tshuab nqus tsev Jackethed tiv thaiv corrosion, kom ua tau ntev ntev ntev thiab kev ntseeg tau nyob rau hauv ib puag ncig muaj kev nyab xeeb.
- Kev Nruab Nrab Yooj Yim thiab Kev Txij Nkawm: Lub tshuab nqus tsev Jacketed yeeb yog tsim nrog tus neeg siv yooj yim hauv siab. Nws cov qauv kev tsim kho tso cai rau kev teeb tsa yooj yim, thaum cov kev saib xyuas tsawg yuav pab kom ua kom tau zoo thiab tsim khoom.
Khoom Paub meej:
- Txhim Kho Rwb Thaiv Tsev: Lub tshuab nqus tsev Jackinged yeeb yog tsim nrog ob lub tshuaj Pipes ob leeg, tsim lub tshuab nqus tsev ntawm lawv. Lub tshuab nqus tsev hluav taws xob ua kom zoo me me hloov chaw, kom ua kom cov kua dej sab hauv cov yeeb nkab hauv cov yeeb nkab tswj lawv qhov kev xav tau kub.
- Txo kev ua haujlwm thaum tshav kub kub: los ntawm kev siv ntau txheej fawm kib, peb lub tshuab nqus tsev ntxig, peb lub tshuab nqus tsev ntxig, peb lub tshuab nqus tsev uas siv hluav taws xob thaum lub sijhawm ua dej lossis roj av. Qhov kev ua tau zoo no ua rau kev txhim kho kev ua haujlwm, txo cov nqi ua haujlwm, thiab txhim kho cov txheej txheem tswj.
- Corrosion Kuj: Peb lub nqus plua plav Jacketed yeeb yog tsim tau siv cov ntaub ntawv corrosion-resistant cov ntaub ntawv xws li stainless hlau. Qhov no ua kom muaj kev ua kom ntev thiab tiv thaiv kev txhim kho ntawm cov dej xau lossis lwm yam teeb meem, txawm tias muaj kev lag luam teeb tsa.
- Kev Nruab Nrab Yooj Yim thiab Kev Txij Nkawm: Cov qauv tsim ntawm lub tshuab nqus tsev Jacking Ua kom yooj yim dua cov txheej txheem teeb tsa, tso cai rau kev teeb tsa nrawm dua thiab tsis muaj teeb meem. Tsis tas li ntawd, kev saib xyuas me me yuav tsum tau txo qis qis, kom ua haujlwm tsis muaj kev cuam tshuam.
Daim duab
Lub Tshuab Nqus Tsev Ronsulated Piping
Lub tshuab nqus tsev insulated (vi piping), uas yog lub tshuab nqus tsev jackinged yeeb (vj piping), raws li ib qho zoo tshaj plaws hloov chaw rau cov piping piping rwb thaiv tsev. Piv nrog cov piping cov piping rwb thaiv tsev, cov cua sov kom tus nqi ntawm VIP tsuas yog 0.035 zaug ntawm cov piping piping rwb thaiv tsev. Tseem txuag txuag lub zog thiab tus nqi rau cov neeg siv khoom.
Cov khoom series ntawm lub tshuab nqus tsev Jose, lub tshuab ua kom zoo nkauj, yog siv rau kev hloov ua kua, ua kua nitrogen, kua argon, kua hydrogen, cov kua rau hauv caug, ceg thiab cov khoom lag luam, cov khoom siv hluav taws xob, cov tshuab raj, khoom siv hluav taws xob, khoom noj khoom haus & dej, tsev muag tshuaj, tsev kho mob, roj hmab, khoom siv tshiab tsim tshuaj engineering, Hlau & Science etc.
Peb hom kev sib txuas ntawm VI PIPING
Qhov peb txuas txuas ntawm no tsuas yog siv rau cov haujlwm sib txuas ntawm VI kav. Thaum VI yeeb nkab txuas nrog cov cuab yeej siv, ntim tank thiab lwm yam tuaj yeem kho tau raws li cov neeg siv khoom.
Txhawm rau kom ua kom tiav cov kev xav tau ntawm cov neeg siv khoom sib txawv, lub tshuab nqus tsev insulated tau tsim peb hom kev sib txuas, lub tshuab nqus tsev bayoning thiab bolts thiab welded txuas hom. Lawv nyias muaj qhov zoo sib txawv thiab tsim nyog rau cov haujlwm sib txawv.
Cov tau txais daim ntawv thov
VAcuum Bayonet Kev Txuas Txuas Hom nrog Clamps | Nqus bayonet txuas hom nrog flanges thiab bolts | Welded Txuas Hom | |
Kev Sib Txuas Hom | Clamps | Flanges thiab bolts | Weld |
Rwb thaiv tsev hom ntawm pob qij txha | Lub tshuab nqus tsev | Lub tshuab nqus tsev | Perlite lossis lub tshuab nqus tsev |
On-site ovulated kev kho mob | No | No | Yog lawm, perlite tau sau rau hauv lossis lub tshuab nqus tsev tawm ntawm cov tes tsho insulated ntawm pob qij txha. |
Nominal diam ntawm cov yeeb nkab sab hauv | DN10 (3/8 ") ~ DN25 (1") | DN10 (3/8 ") ~ Dn80 (3") | DN10 (3/8 ") ~ Dn500 (20") |
Tsim Kev Tsim Nyuaj Siab | ≤8 bar | Hais lus Bar | 5064 bar |
Kev muab cia | Yooj yim | Yooj yim | Weld |
Tsim Ntsuas Kub | -196 ℃ ~ 90 ℃ (LH2 & LHE: -270 ℃ ~ 90 ℃) | ||
Qho ntev | 1 ~ 8.2 'meter' / pcs | ||
Khoom | 300 series cov hlau stainless | ||
Nruab nrab | LN2, LEX, LAT, LHE, LH2, Txhais ceg, lng |
Khoom Muag Khoom Ntawm Cov Khoom Noj
Khoom | Kev qhia tshwj xeeb | Nqus Plastamonet Kev Txuas Nrog Clamps | Nqus bayonet txuas nrog flanges thiab bolts | Weld Insulated Kev Txuas |
Lub Tshuab Nqus Tsev Insulated | Dn8 | Tau | Tau | Tau |
DN15 | Tau | Tau | Tau | |
Dn20 | Tau | Tau | Tau | |
DN25 | Tau | Tau | Tau | |
Dn32 | / | Tau | Tau | |
Dn40 | / | Tau | Tau | |
Dn50 | / | Tau | Tau | |
DN65 | / | Tau | Tau | |
Dn80 | / | Tau | Tau | |
DN100 | / | / | Tau | |
DN125 | / | / | Tau | |
DN150 | / | / | Tau | |
Dn200 | / | / | Tau | |
DN250 | / | / | Tau | |
Dn300 | / | / | Tau | |
DM400 | / | / | Tau | |
DM500 | / | / | Tau |
Cov yam ntxwv ua txuj ci
Tus Npee Tsim Tsim Kev Tsim Nyog | ≥4.0MPA |
Tsim Ntsuas Kub | -196C ~ 90 ℃ (lh2& Lhe: -270 ~ 90 ℃) |
Thaj kub cua sov | -50 ~ 90 ℃ |
Nqus plua plav toaste | ≤1 * 10-10Pa*m3/S |
Nqus theem tom qab lav | ≤0.1 pa |
Insulated txoj kev | Siab nqus plua plav ntau-txheej rwb thaiv tsev. |
Adsorbent thiab getter | Tau |
Nde | 100% Kev Ntsuas Hluav Taws Xob |
Ntsuas Siab | 1.15 zaug tsim kev tsim siab |
Nruab nrab | LO2, Ln2, Lar, LH2, Lhe, ceg, lng |
Dynamic thiab lub tshuab nqus tsev zoo nkauj insulated
Lub tshuab nqus tsev insulated (vi) cov raj xa dej tuaj yeem faib ua cov qauv tshiab thiab zoo li VI PIPING system.
lLub zoo li cov vi piping yog ua tiav rau hauv lub hoob tsim khoom lag luam.
lLub Dynamic Vi Piping yog muab ntau dua lub chaw nqus tsev lub xeev los ntawm kev ua haujlwm nqus plua plav ntawm lub tsev sib dhos thiab kev kho mob yog tseem nyob hauv cov chaw tsim khoom.
Dynamic Nqus Insulated Piping System | Lub tshuab nqus lub cav hluav taws xob zoo li qub | |
Lub hauv paus rau phau ntawv | Lub tshuab nqus tsev ntawm lub tshuab nqus tsev interllayer yog tus saib xyuas tsis tu ncua, thiab lub tshuab nqus tsev tau tswj hwm kom meej thiab kom ntseeg tau tias lub tshuab nqus tsev | VJPS ua tiav lub tshuab nqus tsev ua haujlwm nyob rau hauv kev tsim khoom cog. |
Qhov Zoo | Lub tshuab nqus tsev khaws cia yog qhov ruaj khov, thaiv cov tshuab nqus tsev ua haujlwm yav tom ntej. | Kev nqis peev ntau dua thiab cov khoom siv yooj yim rau ntawm chaw teeb tsa |
Nqus Plasting Txuas Hom nrog Clamps | Tus kawm | Tus kawm |
Nqus bayonet txuas hom nrog flanges thiab bolts | Tus kawm | Tus kawm |
Welded Txuas Hom | Tus kawm | Tus kawm |
Dynamicual haub nqus dej istulated kav dej: muaj cov kav tshuab nqus tsev av insulated, jumper ntxig thiab nqus cov twj nqus tsev, solenoid li qub thiab nqus pa gauges).
Kev qhia tshwj xeeb thiab qauv
HL-PX-X-000-00-X
Hom
Hl cryogenic khoom
Kev piav txog
PD: Dynamic Vi Yeeb Nkab
PS: Static VI Yeeb Nkab
Kev Sib Txuas Hom
W: Welded hom
B: Lub tshuab nqus tsev bayonet nrog clamps
F: Lub tshuab nqus phom bayonet nrog flanges thiab bolts
Nominal diam ntawm cov yeeb nkab sab hauv
010: DN10
...
080: DN80
...
500: Dn500
Tsim Kev Tsim Nyuaj Siab
08: 8bar
16: 16bar
25: 25bar
32: 32BAR
40: 40bar
Cov Khoom Siv Hauv Cov Hlau Sab Hauv
A: SS304
B: ss304l
C: SS316
D: ss316l
E: Lwm yam
Lub tshuab nqus lub cav hluav taws xob zoo li qub
Mkua hlau | Kev sib txuaNtaus | Nominal diam ntawm cov yeeb nkab sab hauv | Tsim Kev Tsim Nyuaj Siab | KhoomNtawm cov yeeb nkab sab hauv | Lub hom phiaj | Hais txog |
HlpsB01008X | Lub Tshuab Nqus Tsev Bayason Txuas Hom nrog Clamps Rau Cov Pipic Insulated Kav Hlau | DN10, 3/8 " | 8 bar
| 300 series cov hlau stainless | ASME B31.3 | X: Cov khoom siv sab hauv cov yeeb nkab. A yog 304, B yog 304l, C yog 316, D yog 316L, E yog lwm yam. |
HlpsB01508X | DN15, 1/2 " | |||||
HlpsB02008X | DN20, 3/4 " | |||||
HlpsB02508X | DN25, 1 " |
Nominal Diam Ntawm Cov Hlau Sab Hauv:Pom zoo ≤ DN25 lossis 1 ". Los yog xaiv lub tshuab nqus tsev Bayonet thiab bolts (los ntawm DN10, 3/8" rau DN500, 20 " )
Nominal Dever ntawm txheej yeeb:Pom zoo los ntawm cov qauv kev lag luam ntawm hn cryogenic khoom. Nws tseem tuaj yeem tsim raws li cov neeg siv khoom ntawm cov qhua tuaj noj mov.
Tsim Nyuaj Siab: Pom zoo ≤ 8 bar. Los yog xaiv lub tshuab nqus tsev bayonet txuas hom nrog flanges thiab bolts (≤16 bar), Welded Connect hom (≤64 bar)
Cov khoom siv ntawm cov yeeb nkab sab nraud: Yog tsis muaj kev ua tshwj xeeb, cov khoom siv sab hauv thiab sab nraud yeeb nkab yuav raug xaiv tib yam.
Mkua hlau | Kev sib txuaNtaus | Nominal diam ntawm cov yeeb nkab sab hauv | Tsim Kev Tsim Nyuaj Siab | KhoomNtawm cov yeeb nkab sab hauv | Lub hom phiaj | Hais txog |
HlpsF01000X | Lub Tshuab Nqus Tsev Bayason Txuas nrog Flanges thiab Bolts Rau Cov Piping Insulated Kav Hlau | DN10, 3/8 " | 8 ~ 16 bar | 300 series cov hlau stainless | ASME B31.3 | 00: Tsim kev siab. 08 yog 8bar, 16 yog 16bar.
X: Cov khoom siv sab hauv cov yeeb nkab. A yog 304, B yog 304l, C yog 316, D yog 316L, E yog lwm yam. |
HlpsF01500X | DN15, 1/2 " | |||||
HlpsF02000X | DN20, 3/4 " | |||||
HlpsF02500X | DN25, 1 " | |||||
HlpsF03200X | DN32, 1-1 / 4 " | |||||
HlpsF04000X | DN40, 1-1 / 2 " | |||||
HlpsF05000X | DN50, 2 " | |||||
HlpsF06500X | DN65, 2-1 / 2 " | |||||
HlpsF08000X | DN80, 3 " |
Nominal Diam Ntawm Cov Hlau Sab Hauv:Pom zoo ≤ DNT80 lossis 3 ". Los yog xaiv Welded Txuas Hom (los ntawm DNSWAYS txuas hom nrog clamps (los ntawm DNTE BAYSWS (los ntawm DNTE BAYSWS (los ntawm DNTE BAYSWS (los ntawm DN10, 3/8" rau DN25, 1 ").
Nominal Dever ntawm txheej yeeb:Pom zoo los ntawm cov qauv kev lag luam ntawm hn cryogenic khoom. Nws tseem tuaj yeem tsim raws li cov neeg siv khoom ntawm cov qhua tuaj noj mov.
Tsim Nyuaj Siab: Pom zoo ≤ 16 bar. Lossis xaiv Welded Txuas Hom (≤64 bar).
Cov khoom siv ntawm cov yeeb nkab sab nraud: Yog tsis muaj kev ua tshwj xeeb, cov khoom siv sab hauv thiab sab nraud yeeb nkab yuav raug xaiv tib yam.
Mkua hlau | Kev sib txuaNtaus | Nominal diam ntawm cov yeeb nkab sab hauv | Tsim Kev Tsim Nyuaj Siab | KhoomNtawm cov yeeb nkab sab hauv | Lub hom phiaj | Hais txog |
HlpsW01000X | Welded Txuas Ntaus Rau Zoo Li Lub Tshuab Nqus Insulated Piping System | DN10, 3/8 " | 8 ~ 64 bar | 300 series cov hlau stainless | ASME B31.3 | 00: Tsim Kev Tsim Nyuaj Siab 08 yog 8bar, 16 yog 16bar, Thiab 25, 32, 40, 64.
X: Cov khoom siv sab hauv cov yeeb nkab. A yog 304, B yog 304l, C yog 316, D yog 316L, E yog lwm yam. |
HlpsW01500X | DN15, 1/2 " | |||||
HlpsW02000X | DN20, 3/4 " | |||||
HlpsW02500X | DN25, 1 " | |||||
HlpsW03200X | DN32, 1-1 / 4 " | |||||
HlpsW04000X | DN40, 1-1 / 2 " | |||||
HlpsW05000X | DN50, 2 " | |||||
HlpsW06500X | DN65, 2-1 / 2 " | |||||
HlpsW08000X | DN80, 3 " | |||||
HLpsw10000X | DN100, 4 " | |||||
HLPSW M12500X | DN125, 5 " | |||||
HLpsw15000X | DN150, 6 " | |||||
HLpsw20000X | DN200, 8 " | |||||
HLpsw25000X | DN250, 10 " | |||||
HLPSW30000X | DN300, 12 " | |||||
HLPSW35000X | DN350, 14 " | |||||
HLPSW40000X | DN400, 16 " | |||||
HLpsw45000X | DN450, 18 " | |||||
HLPSW50000X | Dn500, 20 " |
Nominal Dever ntawm txheej yeeb:Pom zoo los ntawm cov qauv kev lag luam ntawm hn cryogenic khoom. Nws tseem tuaj yeem tsim raws li cov neeg siv khoom ntawm cov qhua tuaj noj mov.
Cov khoom siv ntawm cov yeeb nkab sab nraud: Yog tsis muaj kev ua tshwj xeeb, cov khoom siv sab hauv thiab sab nraud yeeb nkab yuav raug xaiv tib yam.
Dynamic Nqus Insulated Piping System
Mkua hlau | Kev sib txuaNtaus | Nominal diam ntawm cov yeeb nkab sab hauv | Tsim Kev Tsim Nyuaj Siab | KhoomNtawm cov yeeb nkab sab hauv | Lub hom phiaj | Hais txog |
HlpDB01008X | Lub Tshuab Nqus Tsev Bayason Txuas Hom nrog Clamps Rau Cov Pipic Insulated Kav Hlau | DN10, 3/8 " | 8 bar | 300 series cov hlau stainless | ASME B31.3 | X:Cov khoom siv sab hauv cov yeeb nkab. A yog 304, B yog 304l, C yog 316, D yog 316L, E yog lwm yam. |
HlpdB01508X | DN15, 1/2 " | |||||
HlpdB02008X | DN20, 3/4 " | |||||
HlpdB02508X | DN25, 1 " |
Nominal Diam Ntawm Cov Hlau Sab Hauv:Pom zoo ≤ DN25 lossis 1 ". Los yog xaiv lub tshuab nqus tsev Bayonet thiab bolts (los ntawm DN10, 3/8" rau DN500, 20 " )
Nominal Dever ntawm txheej yeeb:Pom zoo los ntawm cov qauv kev lag luam ntawm hn cryogenic khoom. Nws tseem tuaj yeem tsim raws li cov neeg siv khoom ntawm cov qhua tuaj noj mov.
Tsim Nyuaj Siab: Pom zoo ≤ 8 bar. Los yog xaiv lub tshuab nqus tsev bayonet txuas hom nrog flanges thiab bolts (≤16 bar), Welded Connect hom (≤64 bar)
Cov khoom siv ntawm cov yeeb nkab sab nraud: Yog tsis muaj kev ua tshwj xeeb, cov khoom siv sab hauv thiab sab nraud yeeb nkab yuav raug xaiv tib yam.
Fais fab mob:Lub vev xaib yuav tsum tau muab lub zog ua kom haum rau lub tshuab nqus tsev mus rau lub tshuab nqus tsev thiab qhia kom halry cov ntaub ntawv hluav taws xob cov ntaub ntawv hluav taws xob hauv nroog (voltage thiab hertz)
Mkua hlau | Kev sib txuaNtaus | Nominal diam ntawm cov yeeb nkab sab hauv | Tsim Kev Tsim Nyuaj Siab | KhoomNtawm cov yeeb nkab sab hauv | Lub hom phiaj | Hais txog |
HlpDF01000X | Lub Tshuab Nqus Tsev Bayason Txuas nrog Flanges thiab Bolts Rau Cov Piping Insulated Kav Hlau | DN10, 3/8 " | 8 ~ 16 bar | 300 series cov hlau stainless | ASME B31.3 | 00: Tsim kev siab. 08 yog 8bar, 16 yog 16bar.
X: Cov khoom siv sab hauv cov yeeb nkab. A yog 304, B yog 304l, C yog 316, D yog 316L, E yog lwm yam. |
HlpdF01500X | DN15, 1/2 " | |||||
HlpdF02000X | DN20, 3/4 " | |||||
HlpdF02500X | DN25, 1 " | |||||
HlpdF03200X | DN32, 1-1 / 4 " | |||||
HlpdF04000X | DN40, 1-1 / 2 " | |||||
HlpdF05000X | DN50, 2 " | |||||
HlpdF06500X | DN65, 2-1 / 2 " | |||||
HlpdF08000X | DN80, 3 " |
Nominal Diam Ntawm Cov Hlau Sab Hauv:Pom zoo ≤ DNT80 lossis 3 ". Los yog xaiv Welded Txuas Hom (los ntawm DNSWAYS txuas hom nrog clamps (los ntawm DNTE BAYSWS (los ntawm DNTE BAYSWS (los ntawm DNTE BAYSWS (los ntawm DN10, 3/8" rau DN25, 1 ").
Nominal Dever ntawm txheej yeeb:Pom zoo los ntawm cov qauv kev lag luam ntawm hn cryogenic khoom. Nws tseem tuaj yeem tsim raws li cov neeg siv khoom ntawm cov qhua tuaj noj mov.
Tsim Nyuaj Siab: Pom zoo ≤ 16 bar. Lossis xaiv Welded Txuas Hom (≤64 bar).
Cov khoom siv ntawm cov yeeb nkab sab nraud: Yog tsis muaj kev ua tshwj xeeb, cov khoom siv sab hauv thiab sab nraud yeeb nkab yuav raug xaiv tib yam.
Fais fab mob:Lub vev xaib yuav tsum tau muab lub zog ua kom haum rau lub tshuab nqus tsev mus rau lub tshuab nqus tsev thiab qhia kom halry cov ntaub ntawv hluav taws xob cov ntaub ntawv hluav taws xob hauv nroog (voltage thiab hertz)
Mkua hlau | Kev sib txuaNtaus | Nominal diam ntawm cov yeeb nkab sab hauv | Tsim Kev Tsim Nyuaj Siab | KhoomNtawm cov yeeb nkab sab hauv | Lub hom phiaj | Hais txog |
HlpDW01000X | Welded Txuas Hom Rau Dynamic Nqus Insulated Piping System | DN10, 3/8 " | 8 ~ 64 bar | Tus Hlau Stainless 304, 304L, 316, 316L | ASME B31.3 | 00: Tsim Kev Tsim Nyuaj Siab 08 yog 8bar, 16 yog 16bar, Thiab 25, 32, 40, 64. .
X: Cov khoom siv sab hauv cov yeeb nkab. A yog 304, B yog 304l, C yog 316, D yog 316L, E yog lwm yam. |
HlpDW01500X | DN15, 1/2 " | |||||
HlpDW02000X | DN20, 3/4 " | |||||
HlpDW02500X | DN25, 1 " | |||||
HlpdW03200X | DN32, 1-1 / 4 " | |||||
HlpdW04000X | DN40, 1-1 / 2 " | |||||
HlpdW05000X | DN50, 2 " | |||||
HlpdW06500X | DN65, 2-1 / 2 " | |||||
HlpdW08000X | DN80, 3 " | |||||
HLPDW10000X | DN100, 4 " | |||||
HLPDW12500X | DN125, 5 " | |||||
HLPDW15000X | DN150, 6 " | |||||
HLpdw20000X | DN200, 8 " | |||||
HLPDW25000X | DN250, 10 " | |||||
HLPDW30000X | DN300, 12 " | |||||
HLPDW35000X | DN350, 14 " | |||||
HLPDW40000X | DN400, 16 " | |||||
HLPDW45000X | DN450, 18 " | |||||
HLPDW50000X | Dn500, 20 " |
Nominal Dever ntawm txheej yeeb:Pom zoo los ntawm cov qauv kev lag luam ntawm hn cryogenic khoom. Nws tseem tuaj yeem tsim raws li cov neeg siv khoom ntawm cov qhua tuaj noj mov.
Cov khoom siv ntawm cov yeeb nkab sab nraud: Yog tsis muaj kev ua tshwj xeeb, cov khoom siv sab hauv thiab sab nraud yeeb nkab yuav raug xaiv tib yam.
Fais fab mob:Lub vev xaib yuav tsum tau muab lub zog ua kom haum rau lub tshuab nqus tsev mus rau lub tshuab nqus tsev thiab qhia kom halry cov ntaub ntawv hluav taws xob cov ntaub ntawv hluav taws xob hauv nroog (voltage thiab hertz)