Qhov zoo thiab kev txiav txim siab ntawm kev siv tooj dag fittings rau vaj tse thiab kev lag luam kav dej
Brass tau yog cov khoom siv zoo tshaj plaws rau cov kav dej fittings thiab li qub rau ntau tshaj li ib puas xyoo vim nws cov durability, corrosion resistance, machinability, thiab txhim khu kev qha sealing kev ua tau zoo. Txawm li cas los xij, cov ntsiab lus me me tab sis ntsuas tau hauv tooj dag ua rau muaj kev txhawj xeeb txog kev noj qab haus huv ntawm nws qhov tsim nyog rau cov dej siv tau. Kab lus no tshuaj xyuas qhov laj thawj tom qab kev siv tooj dag fittings thoob plaws hauv ob qho tib si hauv tsev thiab kev siv kav dej. Nws kuj tseem tshawb nrhiav cov kev pheej hmoo ntawm cov hlau lead leaching, lwm yam khoom siv haum, thiab cov kauj ruam los ua kom muaj kev nyab xeeb ntawm cov khoom siv tooj dag rau cov dej haus.
Vim li cas Brass Fittings yog qhov kev xaiv rau cov kav dej?
Brass, ib qho hlau ntawm tooj liab thiab zinc, muaj kev sib xyaw ua ke ntawm cov khoom siv uas txhawb nqa nws txoj kev saws me nyuam raws li cov khoom siv haum ntawm kev xaiv los ntawm lig 1800s mus rau hauv cov kav dej hauv tsev proliferated. Qhov zoo tshaj plaws ntawm tooj dag nws dominance muaj xws li:
Corrosion Resistance
Cov khoom siv tooj dag tsis xeb lossis khaws cov pob zeb hauv av zoo li cov khoom siv hlau, ua kom cov dej ntws zoo. Cov tooj liab oxide patina passivates saum npoo tiv thaiv ntxiv cov tshuaj tiv thaiv corrosion. Qhov no khaws cia kev khiav hauj lwm zoo thiab tiv thaiv cov dej ntws [1].
Lub zog thiab Durability
Cam khwb cia tooj dag nthuav tawm lub zog tensile siab tshaj 400 MPa, ua rau nws tuaj yeem tiv taus siab loads txog 20 bar thiab kub hloov pauv los ntawm khov rau 150 degree [2]. Brass tsis yog qhov ua rau tawg tsis ua haujlwm los ntawm kev qaug zog lossis dej rauj kev ntxhov siab ntau xyoo dhau los ntawm kev siv.
Machineability
Brass yog nkag tau yooj yim forged thiab machined rau hauv ntau yam ntawm haum geometry xav tau rau cov kav dej. Nws tso cai rau cov creation ntawm precision tapered threads uas khi reliably tsis to los yog deformation [3].
Malleability
Lub malleability ntawm tooj dag yooj yim khoov thiab shaping kev khiav hauj lwm rau fabricate luj tshib thiab adapters. Nws kuj absorbs vibration stresses thiab resists tej zaum tawg puas.
Biofouling Resistance
Brass nto inhibit qhov adhesion thiab loj hlob ntawm cov kab mob, algae, thiab fungi piv rau hlau los yog yas. Qhov no slows microbial corrosion thiab khaws cia dej zoo [4].
Cov ntsiab lus tseem ceeb hauv cov khoom siv tooj dag
Kev koom ua ke ntawm cov hlau lead rau hauv tooj dag txhim kho kev ua haujlwm los ntawm lubricating cov cuab yeej txiav thiab chips thaum tsim khoom. Keeb kwm, cov kav dej tooj dag muaj 2-8 feem pua ua rau kev ua kom zoo tshaj plaws. Txawm li cas los xij, cov hlau lead leaching rau hauv cov khoom siv dej haus ua rau muaj kev phom sij tseem ceeb, tshwj xeeb tshaj yog rau cov menyuam yaus.
EPA's Lead thiab Copper Rule txwv cov hlau lead hauv tooj dag fittings mus rau qhov siab tshaj plaws ntawm {{0}}.25 feem pua rau txhua yam khoom tiv tauj dej haus [5]. California thiab Vermont txoj cai lij choj ntxiv txwv kev tso cai ua rau 0.1 feem pua ntawm cov kav dej tooj dag. Lead hloov cov ntsiab lus suav nrog bismuth, selenium, tellurium, thiab silicon yog tam sim no sib xyaw rau hauv cov qauv tooj dag tsis muaj hlau lead kom ua tiav cov khoom siv thaum ua tau raws cov kev txwv nruj heev [6].
Muaj peev xwm txaus ntshai ntawm Lead Leaching los ntawm cov khoom siv tooj dag
Txawm hais tias niaj hnub tooj dag muaj cov hlau lead tsawg heev, cov nyiaj me me tseem tuaj yeem nkag mus rau hauv cov dej sawv ntsug hauv kev sib cuag nrog tooj dag fittings thiab li qub. Lead ions raug tso tawm thaum lub qhov chaw sab hauv ntawm fittings raug muag muag, acidic, los yog dej sov [7]. Cov dej nyob rau hauv cov yeeb nkab system thaum hmo ntuj maximizes lead dissolution.
Kev noj cov hmoov txhuas feem ntau yog nqus mus rau hauv cov hlab ntsha thiab cov ntaub so ntswg, ua rau mob hnyav thiab mob ntev. Cov menyuam yaus muaj kev phom sij tshaj plaws vim tias txawm tias cov hlau lead tsawg tuaj yeem ua rau puas hlwb kev loj hlob. Cov teebmeem tsis zoo muaj xws li kev paub tsis meej, kev loj hlob stunted, thiab kev coj tus cwj pwm tsis zoo [8]. Thaum cov neeg laus tsis tshua nkag siab, txhuas tuaj yeem ua rau cov ntshav siab, lub raum tsis ua haujlwm, thiab teeb meem kev ua me nyuam.
EPA tau txiav txim kom kho yog tias cov hmoov txhuas ntau tshaj 15 feem ntawm ib billion hauv ntau dua 10 feem pua ntawm cov qauv dej hauv cov dej [5]. Txawm li cas los xij, ntau tus kws tshaj lij tau hais tias qhov pib no yuav tsum qis dua los tiv thaiv pej xeem kev noj qab haus huv, tshwj xeeb tshaj yog rau cov menyuam mos. Xaiv cov khoom siv dej tsis muaj hmoov lead ua rau muaj kev tswj xyuas qhov tseem ceeb kom txo tau cov kev pheej hmoo ntawm cov hlau lead.
Cov lus pom zoo rau kev nyab xeeb ntawm kev siv tooj dag cov kav dej
Cov khoom siv tooj dag tseem tsim nyog rau cov kab kev pabcuam uas muab cov dej tsis muaj dej kom tsis txhob muaj cov hlau lead. Rau cov kav dej siv tau, ntau lub tswv yim tuaj yeem pab txhawb kev nyab xeeb ntawm cov khoom siv tooj dag:
- Xaiv cov hlau lead uas tsis muaj hlau lead lossis cov hlau tsis muaj hlau lead uas tau lees paub los ntawm NSF / ANSI 61 kuaj thaum twg los tau. Qhov no txwv tsis pub coj mus rau hauv qab ntawm 0.25 feem pua.
- Tsis txhob siv cov khoom siv tooj dag nrog cov ntsiab lus txhuas siab tshaj 3 feem pua rau cov kev pabcuam dej haus. Cov qib txhuas siab dua txhawb cov kev pheej hmoo leaching.
- Flushing faucets thiab da dej rau 30 vib nas this tom qab tsaus ntuj stagnation tshem tawm cov hmoov lead-muaj dej los ntawm cov yeeb nkab sab hauv.
- Kev soj ntsuam ib ntus ntawm cov hlau lead hauv cov qauv coj mus kuaj los ntawm cov chaw kuaj mob uas muaj ntawv pov thawj txheeb xyuas txhua yam teeb meem xav tau kev kho.
- Siv cov hlau lead uas tsis yog txhuas rau txhua qhov sib koom ua ke, vim cov hlau lead-raws li tuaj yeem ua rau dej paug.
Lwm cov khoom haum tsis muaj kev txhawj xeeb txog txhuas
Muaj ntau qhov kev xaiv uas tsis yog xim hlau thiab tsis muaj hlau lead-dawb muaj nyob rau hauv cov kav dej fittings uas tsis muaj kev cuam tshuam los ntawm txhuas leaching:
- Cov khoom siv tooj liab tsis muaj cov hlau lead thiab feem ntau siv rau cov kav dej. Tab sis tooj liab yog qhov ua rau muaj kev puas tsuaj ntau dua li tooj dag.
- PVC thiab CPVC yas fittings yog ruaj thiab pheej yig tab sis muaj qis dua thiab kub ntsuas dua tooj dag.
- Stainless hlau fittings ua tau zoo nyob rau hauv corrosion kuj tab sis nyob deb costlier tshaj tooj dag. Cov qib ductile zoo li 316L nyiam dua.
- Bronze fittings tsis muaj hlau lead txawm tias cov ntsiab lus tooj liab siab txo kev tiv thaiv corrosion. Lawv raug nqi txog tsib npaug ntau dua li tooj dag.
Xaus
Brass tau ua cov khoom ntawm kev xaiv rau cov kav dej fittings thiab li qub vim nws qhov kev sib txuam tsis sib xws ntawm lub zog, kev tiv thaiv corrosion, sealing kev ntseeg tau, thiab kev ua haujlwm zoo. Txawm hais tias cov tooj dag ib txwm muaj cov txhuas me me, kev ua raws li cov cai thiab cov kev coj ua zoo tshaj plaws ua rau nws muaj kev nyab xeeb rau kev siv dej haus. Cov hlau tsis muaj hlau lead thiab lwm cov khoom siv haum kuj nthuav dav cov kev xaiv los tsim cov kav dej tsis muaj hlau lead.
Cov ntaub ntawv
[1] V. Ashworth et al., "Puas yog tooj dag yog cov khoom siv nyab xeeb rau kev siv dej hauv tsev?", Dej Science thiab Technology: Dej Supply, vol. 17, nr. 5, pp. 1537-1548, 2017.
[2] MIL-STD-777J, Teem caij ntawm Piping, Valves, Fittings, thiab Associated Piping Cheebtsam rau Naval Surface Ships, Department of Defense, Tebchaws Asmeskas, 30 Lub Kaum Hli 2019.
[3] JA Ginzel, "Kev Tshawb Fawb Txog Qhov Ua Rau Cov Yeeb Nkab Xov Failure," Engineering Failure Analysis, vol. 35, p. 516-535, 2013.
[4] K. Morvay thiab F. Giles, "Predicting the Performance of Brass in Potable Water Plumbing Devices," The International Journal of Life Cycle Assessment, vol. 23, nr. 7, p. 1297-1309, 2018.
[5] EPA, "Lead and Copper Rule," Code of Federal Regulations, 40 CFR 141.43.
[6] CDA - Copper Development Association, "Lead-Free Brass Alloys," 2020.
[7] S. Schock thiab K. Lytle, "Internal Corrosion and Deposition Control," in Water Quality and Treatment, Letterman, RD, Ed. New York: McGraw-Hill, 1999.
[8] ATSDR, "Lead Toxicity: Dab Tsi Yog Qhov Kev Tiv Thaiv Lub Cev Los Ntawm Lead Exposure?", US Department of Health thiab Human Services, 2020.
