Xaiv cov khoom tsim nyog rau lub qhov hluav taws kub hydrant valve yog qhov tseem ceeb rau kev ua haujlwm ntev thiab kev ntseeg tau. Aluminium thiab tooj dag, ob yam khoom siv feem ntau, muaj qhov zoo sib xws. Aluminium yog lub teeb yuag thiab tus nqi zoo, thaum tooj dag muab lub zog zoo dua thiab tiv thaiv corrosion. Rau kev siv OEM, kev xaiv cov khoom siv ncaj qha cuam tshuam rau kev ua haujlwm ntev thiab kev ua haujlwm. Cov ntaub ntawv zoo, xws li cov hlau tiv thaiv corrosion, pab li qub tiv taus qhov chaw hnyav thiab siv txuas ntxiv. Kev xaiv tsis zoo tuaj yeem ua rau hnav ntxov ntxov lossis ua tsis tiav. Aluminium suits daim ntaub ntawv uas yuav tsum tau lub teeb yuag Cheebtsam, whereas tooj dag excels nyob rau hauv xav tau ib puag ncig xav tau kev txhim kho durability.
Ntsiab Cai
- Xaiv aluminium yog tias koj xav tau lub teeb thiab pheej yig hluav taws kub hydrant li qub. Nws qhov hnyav qis ua rau nws yooj yim rau siv thiab nruab, txuag nyiaj ntawm kev ua haujlwm.
- Mus nrog tooj dag raumuaj zog thiab tawv li qubnyob rau hauv tej yam kev mob nyuaj. Brass ua haujlwm zoo nyob rau hauv lub siab hnyav thiab kav ntev.
- Xav txog kev tiv thaiv xeb thaum xaiv cov khoom siv. Aluminium muaj txheej txheej ntuj uas tsis xeb, tab sis tooj dag xav tau kev saib xyuas hauv qhov chaw ntub dej.
- Saibtag nrho cov nqi dhau sijhawm. Aluminium yog pheej yig dua los yuav thiab kho, tab sis tooj dag kav ntev dua, uas tuaj yeem ua rau nws tus nqi siab dua.
- Xyuas kom cov valves ua raws li cov cai kev nyab xeeb. Xyuas kom lawv muaj ntawv pov thawj zoo li UL, FM, thiab ISO rau kev nyab xeeb thiab kev ntseeg siab.
Cov Khoom Siv Hluav Taws Xob Hluav Taws Xob Valve
Lub zog thiab Durability
Aluminium lub zog
Thaum nws los txog rau lub zog, aluminium muaj qhov zoo tshaj plaws lub zog-rau-qhov hnyav piv. Nyob ntawm cov alloy, nws lub zog tensile ranges ntawm 70 MPa rau 700 MPa. Qhov no ua rau nws muaj ntau yam kev xaiv rau cov ntawv thov uas xav tau lub teeb yuag tsis tau ruaj khov. High-strength aluminium alloys, xws li 7075-T6, tuaj yeem ua tau zoo tshaj tooj dag hauv lub zog tensile thaum tswj qhov hnyav dua. Aluminium kuj ua tau zoo nyob rau hauv cov xwm txheej dynamic loading, raws li nws yooj yooj yim tso cai rau nws nqus thiab rov faib kev ntxhov siab zoo. Qhov no ua rau nws tshwj xeeb tshaj yog haum rau cov hluav taws kub hydrant li qub siv nyob rau hauv qhov chaw muaj kev ntxhov siab.
tooj dag lub zog
Brass, ntawm qhov tod tes, paub txog nws lub zog tensile zog, feem ntau yog li ntawm 250 MPa txog 500 MPa. Nws cov hardness nruab nrab thiab durability ua rau nws zoo tagnrho rau cov haujlwm hnyav uas lub zog tseem ceeb heev. Tsis zoo li txhuas, tooj dag muab kev ua haujlwm zoo ib yam hauv cov khoom zoo li qub, ua rau nws muaj kev ntseeg siab rau cov hluav taws kub hydrant li qub hauv kev xav tau. Nws muaj peev xwm tiv taus hnav thiab tsim kua muag thaum lub sijhawm ua kom muaj kev ua haujlwm ntev, tshwj xeeb tshaj yog nyob rau hauv kev lag luam.
Corrosion Resistance
Aluminium's Corrosion Resistance
Aluminium stands rau nwsexceptional corrosion kuj, ua tsaug rau nws cov txheej txheem oxide. Cov txheej tiv thaiv no tiv thaiv cov khoom los ntawm cov dej noo thiab cov pa phem, ua rau nws zoo tagnrho rau qhov chaw sab nraum zoov. Cov hluav taws kub hydrant li qub ua los ntawm txhuas ua tau zoo nyob rau hauv cov xwm txheej hnyav, suav nrog raug los nag, av noo, thiab cov pa phem. Qhov kev ua haujlwm ntev no txo qhov kev xav tau ntawm kev saib xyuas tsis tu ncua, ua kom muaj kev ntseeg tau ntev.
Brass's Corrosion Resistance
Brass, thaum lub sij hawm ntev, muaj kev cuam tshuam ntau dua rau tarnishing thiab dezincification nyob rau hauv qhov chaw ntub dej lossis chloride-nplua nuj. Cov yam ntxwv no tuaj yeem ua rau nws cov qauv tsis muaj zog thaum lub sijhawm. Txawm li cas los xij, nrog kev saib xyuas kom zoo thiab cov txheej txheem tiv thaiv, tooj dag tseem tuaj yeem ua tau zoo hauv qhov chaw qis dua. Rau qhov hluav taws kub hydrant li qub siv nyob rau hauv qhov chaw tswj, tooj dag tseem yog ib qho kev xaiv siv tau.
Qhov hnyav thiab tuav
Aluminium Lub Teeb Pom Kev Zoo
Aluminium qhov ntom ntom ntawm 2.70 g / cm³ ua rau nws hnyav dua li tooj dag. Qhov xwm txheej no yooj yim rau kev tuav thiab teeb tsa, tshwj xeeb tshaj yog hauv cov ntawv thov uas qhov hnyav yog qhov tseem ceeb. Hluav taws kub hydrant li qub ua los ntawm txhuas yog yooj yim rau kev thauj thiab nruab, txo cov nqi zog thiab kev siv zog. Qhov txiaj ntsig no tshwj xeeb tshaj yog muaj txiaj ntsig hauv cov haujlwm loj lossis cov chaw nyob deb.
Brass's Weight Implications
Brass, nrog qhov ceev ntawm 8.4 txog 8.7 g / cm³, hnyav dua li txhuas. Thaum qhov hnyav ntxiv no ua rau nws lub zog thiab ua haujlwm ntev, nws tuaj yeem tsim teeb meem thaum tuav thiab teeb tsa. Cov hluav taws kub hydrant li qub ua los ntawm tooj dag yuav xav tau kev txhawb nqa ntxiv lossis cov khoom siv rau kev teeb tsa, nce nqi tag nrho ntawm qhov project. Txawm li cas los xij, qhov hnyav ntxiv tuaj yeem muab kev ruaj ntseg hauv qee yam kev siv, ua tooj dag yog qhov kev xaiv zoo tshaj plaws hauv cov xwm txheej tshwj xeeb.
Kev txiav txim siab nqi rau cov hluav taws kub hnyiab li qub
Tus nqi khoom pib
Nqi ntawm Aluminium
Aluminium muaj akev daws teeb meem raug nqirau hluav taws hydrant li qub. Nws txoj kev nplua nuj thiab kev yooj yim ntawm kev tsim khoom ua rau nws pheej yig. Piv rau tooj dag, txhuas muaj tus nqi qis dua, ua rau nws muaj kev xaiv zoo rau OEMs txhawm rau txo qis cov nqi pib. Tsis tas li ntawd, nws cov recyclability ua kom cov khoom ruaj khov, txo qhov kev pheej hmoo ntawm tus nqi hloov pauv.
Nqi ntawm tooj dag
Brass, thaum ruaj thiab txhim khu kev qha, nyiam uakim dua vimnws cov ntsiab lus tooj liab thiab lub zog-intensive manufacturing txheej txheem. Piv txwv li:
- Brass fire hydrant li qub feem ntau yog li ntawm $ 0.15 txog $ 5 ib thooj.
- Storz fire hydrant li qub, uas feem ntau siv tooj dag, muaj li ntawm $ 12.00 txog $ 16.00.
Cov nqi siab dua no qhia txog cov khoom siv lub zog thiab kev ua haujlwm tab sis tuaj yeem ua rau muaj kev sib tw rau cov phiaj xwm nyiaj txiag.
Cov nqi tu ncua sij hawm ntev
Kev kho rau Aluminium Valves
Aluminium li qub xav tau kev saib xyuas tsawg heev vim lawv qhov kev tiv thaiv corrosion. Cov txheej txheej oxide uas tsim rau ntawm txhuas qhov chaw tiv thaiv kev puas tsuaj ib puag ncig, txo qhov xav tau kev kho ntau zaus lossis hloov pauv. Cov yam ntxwv no ua rau txhuas tus nqi tsim nyog rau kev siv mus sij hawm ntev nyob rau hauv sab nraum zoov lossis ntub dej.
Kev kho rau Brass Valves
Brass li qub xav tau kev saib xyuas ntxiv kom tswj tau lawv txoj kev ncaj ncees. Hauv thaj chaw muaj chloride-nplua nuj los yog cov av ntub heev, tooj dag tuaj yeem ua rau dezincification, uas ua rau cov khoom tsis muaj zog thaum lub sijhawm. Kev tshuaj xyuas tsis tu ncua thiab cov txheej tiv thaiv yog tsim nyog los txuas ntxiv lub neej ntawm tooj dag hluav taws kub hydrant li qub. Thaum cov kev ntsuas no ua kom ruaj khov, lawv kuj nce nqi kho.
Lifecycle tus nqi
Aluminium tag nrho cov nqi ntawm cov tswv
Aluminium muab cov txiaj ntsig zoo rau lub neej vim nws cov nqi pib qis thiab kev saib xyuas tsawg kawg nkaus. Nws lub teeb yuag txo cov nqi tsheb thauj mus los thiab kev teeb tsa, ntxiv dag zog rau nws cov nqi-zoo. Tsis tas li ntawd, aluminium qhov sustainability thiab recyclability pab txhawb rau nws thov rau tej yaam num ib puag ncig.
Brass's Total Cost of Ownership
Brass muaj tus nqi siab dua tab sis them nyiaj nrog nws cov kav ntev thiab kev ntseeg siab hauv cov ntawv thov. Txawm hais tias xav tau kev saib xyuas ntau dua, nws muaj peev xwm tiv taus hnav thiab tsim kua muag kom ua haujlwm ntev. Rau kev lag luam ua ntej qhov tseem ceeb ntawm lub zog thiab kev ua tau zoo, tooj dag tseem yog kev nqis peev tseem ceeb.
Lub rooj sib piv
| Yam | tooj dag | Aluminium |
|---|---|---|
| Tus nqi khoom siv | Tus nqi kim kim heev vim cov nqi tooj liab siab thiab kev siv zog ntau lawm. | Ntau dua thiab yooj yim dua los tsim, muab cov ntsiab lus qis dua. |
| Muaj | Tej zaum yuav ntsib teeb meem khoom, tshwj xeeb tshaj yog rau cov khoom siv tshwj xeeb. | Thoob ntiaj teb muaj ntau thiab rov ua dua tshiab, ua kom muaj kev yooj yim dua rau kev tsim khoom ntau. |
| Environmental Impact | Cov txheej txheem siv hluav taws xob ntau dua. | Tsawg zog xav tau thiab zoo dua recyclability, ua rau nws ruaj khov dua. |
Daim ntawv thov tsim nyog ntawm Cov Hluav Taws Xob Hluav Taws Xob Valve
Environmental Factors
Aluminium nyob rau hauv qhov kub thiab txias
Aluminium ua tau zoo nyob rau hauv huab cua kub vim nws zoo heev thermal conductivity thiab tsis kam mus thermal expansion. Qhov no ua rau nws yog qhov kev xaiv txhim khu kev qha rau cov hluav taws kub hydrant li qub raug rau qhov kub thiab txias. Aluminium lub peev xwm los dissipate tshav kub sai sai kom ntseeg tau tias nws tswj kev ncaj ncees txawm nyob rau hauv high-temperature ib puag ncig. Tsis tas li ntawd, nws qhov hnyav hnyav txo qhov kev ntxhov siab ntawm cov khoom sib txuas, txhim kho kev ua haujlwm tag nrho.
Brass nyob rau hauv kub heev
Brass muaj qhov zoo tshaj thermal stability, ua rau nws zoo tagnrho rau cov ntawv thov uas xav tau kev ua haujlwm zoo ib yam hauv cov cua sov. Nws cov ntsiab lus melting ntau dua thiab rigidity tso cai rau nws los tiv thaiv lub sijhawm ntev ntawm qhov kub thiab txias yam tsis muaj deforming. Brass fire hydrant li qub yog tshwj xeeb tshaj yog zoo nyob rau hauv kev lag luam chaw uas kub kuj tseem ceeb heev. Txawm li cas los xij, nyob rau hauv cov xwm txheej khov, tooj dag lub rigidity tuaj yeem ua rau nws yooj yim dua rau kev tawg raws li kev hloov pauv sai.
Kev Xav Tau Kev Ua Haujlwm
Aluminium rau High-Pressure Systems
Aluminium excels nyob rau hauv high-pressure systems uas xav tau yooj yim thiab qaug zog kuj. Nws muaj peev xwm nqus tau thiab rov faib cov kev ntxhov siab ua rau nws tsim nyog rau kev siv dynamic nrog kev sib txawv ntawm qhov siab thiab ntws. Cov txiaj ntsig tseem ceeb muaj xws li:
- Kev tsim kho lub teeb yuag, txo kev ntxhov siab ntawm qhov system.
- Superior qaug zog tsis kam, ua kom muaj zog nyob rau hauv kev rov ua haujlwm siab.
- Siab zog-rau-qhov hnyav piv, uas txhawb kev ua haujlwm zoo hauv qhov xav tau ib puag ncig.
Brass rau High-Pressure Systems
Brass yog cov khoom siv mus rau cov khoom siv thauj khoom zoo li qub uas xav tau rigidity thiab hnav tsis kam. Nws hardness thiab tensile lub zog ua rau nws zoo tagnrho rau hnyav-lub luag hauj lwm hluav taws kub hydrant li qub ua hauj lwm nyob rau hauv raws li kev kub siab. Txawm hais tias tsis yooj yim dua li txhuas, tooj dag muab qhov tsis sib haum xeeb nyob rau hauv cov tshuab uas cuam tshuam thiab kev ntseeg tau ntev yog qhov tseem ceeb.
| Feature | Aluminium Qhov Zoo | Brass Advantages |
|---|---|---|
| Tensile zog | Qee qhov muaj zog aluminium alloys tuaj yeem tshaj tooj dag lub zog thaum sib dua. | Feem ntau muaj zog tensile ntau dua, haum rau kev siv hnyav. |
| Hardness | Tsawg hardness tab sis haum rau daim ntawv thov xav tau yooj. | Superior hardness, zoo tagnrho rau hnav tsis kam. |
| Yooj yim | Superior yooj tso cai rau deformation yam tsis muaj cracking, tseem ceeb nyob rau hauv dynamic daim ntaub ntawv. | Tsawg yoog raws, nruj dua. |
| Fatigue Resistance | Kev qaug zog zoo dua vim nws muaj peev xwm nqus tau thiab rov faib kev ntxhov siab. | Zoo qaug zog tsis kam, tab sis tsis hloov pauv. |
Kev lag luam-Specific Applications
Aluminium hauv kev siv OEM
Aluminium fire hydrant li qub tau siv dav hauvKev thov OEMvim lawv lub teeb yuag thiab raug nqi zoo. Lawv yog tshwj xeeb tshaj yog haum rau cov tshuab uas yuav tsum tau dynamic Cheebtsam los yog kev cai configurations. Aluminium lub recyclability kuj ua rau nws ib puag ncig tus phooj ywg xaiv rau kev lag luam ua ntej qhov tseem ceeb ntawm sustainability.
Brass hauv OEM daim ntawv thov
Brass tseem yog cov khoom siv rau OEM daim ntawv thov uas xav tau kev ua haujlwm ntev thiab lub zog. Nws muaj peev xwm tiv taus hnav thiab tsim kua muag ua rau nws zoo tagnrho rau kev siv hluav taws xob tiv thaiv hluav taws xob thiab cov tshuab hluav taws xob. Brass li qub feem ntau xaiv rau lawv txoj kev ntseeg siab hauv kev tswj cov dej ntws hauv kev ua haujlwm tua hluav taws.
| Hom ntawv thov | Kev piav qhia |
|---|---|
| Hluav taws xob Hydrant Systems | Tswj cov dej ntws hauv kev ua haujlwm tua hluav taws. |
| Sprinkler Systems | Tswj kev xa dej hauv ob qho tib si kev lag luam thiab kev tua hluav taws hauv tsev. |
| Kev Tiv Thaiv Hluav Taws Xob Hluav Taws Xob | Siv rau hauv cov chaw loj loj los tswj cov dej tua hluav taws kom zoo. |
| Kev daws teeb meem | Haum rau cov khoom siv tua hluav taws tshwj xeeb lossis tshwj xeeb kev teeb tsa. |
Regulatory and Industry Standards for Fire Hydrant Valves
Cov qauv tsim nyog
API Standards
Kuv ib txwm hais txog qhov tseem ceeb ntawm kev ua raws li API (American Petroleum Institute) cov qauv thaum xaiv cov khoom siv hluav taws kub hydrant li qub. Cov qauv no xyuas kom meej tias cov li qub ua tau raws li kev ua tau zoo thiab cov qauv kev nyab xeeb. API-certified li qub qhia kev ntseeg tau nyob rau hauv high-pressure thiab high-temperature tej yam kev mob. Rau OEMs, ua raws li cov qauv API tau lees paub tias cov li qub tuaj yeem ua raws li qhov xav tau ntawm kev ua haujlwm ib puag ncig yam tsis muaj kev cuam tshuam txog kev nyab xeeb.
JIS thiab BS Standards
Ntxiv rau API, Kuv feem ntau pom zoo kom xav txog JIS (Japanese Industrial Standards) thiab BS (British Standards) cov ntawv pov thawj. JIS cov qauv tsom mus rau qhov tseeb thiab qhov zoo, ua rau lawv zoo tagnrho rau cov ntawv thov uas xav tau qhov tseeb ntawm qhov tseeb. BS cov qauv, ntawm qhov tod tes, hais txog kev ruaj ntseg thiab kev nyab xeeb, tshwj xeeb tshaj yog nyob rau hauv kev lag luam thiab hauv nroog. Los ntawm kev ua raws li cov qauv ntsuas thoob ntiaj teb no, cov hluav taws kub hydrant li qub tau txais kev lees paub thoob ntiaj teb, ua kom muaj kev sib raug zoo thiab kev ntseeg siab thoob plaws ntau lub khw.
Cov ntawv pov thawj thiab kev ua raws cai
Aluminium Valve Certifications
Aluminium li qub yuav tsum ua raws li cov ntawv pov thawj xws li UL (Underwriters Laboratories), FM (Factory Mutual), thiab ISO (International Organization for Standardization). Cov ntawv pov thawj no ua pov thawj tias lub valve muaj peev xwm tiv taus ib puag ncig kev ntxhov siab thiab tswj kev ua haujlwm dhau sijhawm. Kuv pom tias UL thiab FM ntawv pov thawj muaj txiaj ntsig tshwj xeeb rau kev ua kom muaj kev nyab xeeb ntawm hluav taws, thaum ISO cov qauv lees paub qhov zoo thiab qhov sib xws. Kev tsis ua raws cai tuaj yeem ua rau muaj kev pheej hmoo nyab xeeb thiab teeb meem kev cai lij choj, yog li kuv ib txwm saib xyuas cov khoom muaj ntawv pov thawj.
Brass Valve Certifications
Brass li qub tseem xav tau UL, FM, thiab ISO daim ntawv pov thawj kom ua tau raws li kev xav tau ntawm kev lag luam. Cov ntawv pov thawj no lees paub tias cov li qub tuaj yeem tiv taus qhov hnyav, suav nrog kev kub siab thiab corrosive ib puag ncig. Kuv feem ntau hais txog tias tooj dag li qub nrog cov ntawv pov thawj no muaj kev txhim kho kev ntseeg tau thiab siv tau ntev. Rau OEMs, kev nqis peev hauv cov ntaub ntawv pov thawj tooj dag txo qis kev pheej hmoo ua haujlwm thiab ua kom muaj kev ua raws li cov cai tswj hwm.
Tswv yim: Nco ntsoov xyuas kom tseeb tias koj lub qhov hluav taws kub hydrant li qub muaj cov ntawv pov thawj tsim nyog. Cov kauj ruam no tsis tsuas yog ua kom muaj kev nyab xeeb xwb tab sis kuj tseem tiv thaiv kev lav phib xaub.
Aluminium thiab tooj dag muaj qhov zoo sib xws rau cov hluav taws kub hydrant li qub. Aluminium muab lub teeb yuag, kev siv nyiaj tsawg, thiab kev tiv thaiv corrosion zoo heev, ua rau nws zoo tagnrho rau kev siv hluav taws xob lossis cov ntawv loj. Brass, nrog nws lub zog zoo dua thiab ua haujlwm ntev, ua tau zoo nyob rau hauv kev xav tau ib puag ncig uas yuav tsum tau muaj kev ntseeg siab ntev. OEMs yuav tsum saib xyuas cov ntaub ntawv tseem ceeb uas ua tau raws li cov qauv kev lag luam xws li UL, FM, lossis ISO daim ntawv pov thawj kom muaj kev nyab xeeb thiab ua raws. Xaiv cov hlau uas muaj corrosion-resistant, txhim khu kev ruaj ntseg, txo cov nqi tu, thiab ncua kev ua neej nyob. Kev xaiv cov khoom siv nrog cov hom phiaj ua haujlwm ua kom pom kev ua haujlwm zoo thiab raug nqi.
FAQ
Dab tsi yog qhov sib txawv tseem ceeb ntawm txhuas thiab tooj dag hluav taws kub hydrant li qub?
Aluminium li qub yog lub teeb yuag, tus nqi-zoo, thiab corrosion-resistant, ua rau lawv zoo tagnrho rau kev siv dynamic. Brass li qub, ntawm qhov tod tes, muab lub zog zoo dua, ua haujlwm ntev, thiab thermal stability, zoo heev hauv qhov xav tau ib puag ncig. Kuv pom zoo xaiv raws li koj qhov kev xav tau ua haujlwm tshwj xeeb thiab ib puag ncig.
Kuv yuav txiav txim siab li cas cov ntaub ntawv twg zoo dua rau kuv daim ntawv thov?
Xav txog tej yam xws li kev cuam tshuam ib puag ncig, kev xav tau siab, thiab pob nyiaj siv. Aluminium suits lub teeb yuag, corrosion-resistant kev xav tau, thaum tooj dag ua haujlwm zoo tshaj plaws rau kev ua haujlwm hnyav, lub zog siab. Kuv ib txwm qhia txog kev xaiv cov khoom siv nrog koj lub hom phiaj kev ua haujlwm thiab cov qauv kev lag luam rau kev ua haujlwm zoo.
Puas yog txhuas qhov hluav taws kub hydrant li qub ruaj txaus rau siv sab nraum zoov?
Yog, aluminium li qub ua tau zoo heev sab nraum zoov. Lawv cov txheej txheem oxide ntuj tiv thaiv kev ya raws, muaj kuab paug, thiab xeb. Kuv pom tias lawv muaj txiaj ntsig tshwj xeeb hauv qhov chaw ntub dej lossis los nag, qhov uas lawv xav tau kev saib xyuas tsawg thiab muaj kev ntseeg tau ntev.
Puas yog tooj dag li qub xav tau kev saib xyuas ntau dua li aluminium li qub?
Brass li qub xav tau kev tshuaj xyuas tsis tu ncua thiab cov txheej txheem tiv thaiv, tshwj xeeb tshaj yog nyob rau hauv chloride-nplua nuj los yog qhov chaw ntub dej, tiv thaiv dezincification. Aluminium li qub, nrog rau lawv cov kev tiv thaiv corrosion, thov tsis tu ncua. Kuv pom zoo kom ntsuas cov nqi kho mob thaum xaiv cov khoom siv rau koj qhov hluav taws kub hydrant li qub.
Ob leeg txhuas thiab tooj dag li qub puas tuaj yeem ua tau raws li cov qauv kev lag luam?
kiag li. Ob qho khoom siv tuaj yeem ua raws li cov ntawv pov thawj xws li API, JIS, BS, UL, FM, thiab ISO. Kuv ib txwm hais txog kev txheeb xyuas cov ntawv pov thawj kom muaj kev nyab xeeb, kev ntseeg siab, thiab ua raws li cov cai tswj hwm. Cov ntawv pov thawj li qub lav kev ua haujlwm thiab txo cov kev pheej hmoo ua haujlwm.
Post lub sij hawm: Mar-08-2025