Iyini i-valve yokuphepha?
I-valve yokuphepha komfutho (i-acronym PSV) iyisisetshenziswa esizishintshayo esinendawo yokungena kanye ne-outlet, ngokuvamile encike ku- each enye (ku-90°), ekwazi ukwehlisa ingcindezi ngaphakathi kwesistimu.
Isithombe esingakwesokunxele simele umdwebo onesitayela wevalvu yokuphepha, osetshenziswa njengophawu emidwebeni yobunjiniyela yezinhlelo ze-thermo-hydraulic.
Ama-valve okuphepha angamathuluzi okusiza izimo eziphuthumayo kuketshezi olucindezelwe, okuthi ukusebenza ngokuzenzakalelayo lapho ingcindezi ebekiwe idlula. Lawa ma-valve alawulwa yizwe kanye nakwamanye amazwe standI-ARDS. Ama-valve ethu kufanele alingane, ahlolwe, afakwe futhi kugcinwe ngokuhambisana nemithethonqubo yamanje kanye nanjengoba kubekwe ezincwadini zethu zokufundisa.
Besa® amavalvu okuphepha ziwumphumela wolwazi oluningi, kusukela ngo-1946 kuze kube namuhla, emikhakheni ehlukahlukene yokusetshenziswa futhi enelise kakhulu zonke izidingo ze ukuvikela idivayisi yengcindezi yakamuva. Ziyakwazi ngokuphelele ukungeqi ukucindezela okuphezulu okuvunyelwe, ngisho noma wonke amanye amadivaysi okuphepha azimele afakwe phezulu nomfula ehlulekile.
Izingxenye eziyinhloko ze-valve yokuphepha ziboniswa emfanekisweni:
Qaphela ekusetshenzisweni nasekusetshenzisweni kwesileva sediski
I-disc lift lever iyi-accessory ukuthi i-valve yokuphepha ingahlonyiswaped nge, lokho kuvumela ukuphakamisa ingxenye yediski. Ngokuvamile, inhloso yalokhu kuqondisa iwukuba - ngesikhathi sokusebenza kwe-valve - ukuphunyuka kwe-valve process uketshezi ukuze hlanza izindawo phakathi kwesihlalo nediski, ibheka noma yikuphi "okunamathelayo" okungenzeka. Ukuqondisa ngokuphakamisa i-shutter ngesandla, kufanele kwenziwe nge-valve efakwe kahle ohlelweni olusebenzayo futhi phambi kwenani elithile lokucindezela, ukuze ukwazi ukuzuza ukucindezela okwenziwa yi- process uketshezi ukunciphisa umzamo womsebenzisi owenziwe ngesandla.
Umlando we-valve yokuphepha
Eminyakeni eminingi edlule, emigwaqweni yase-Asia yasendulo, irayisi elikhukhumele lalisetshenziselwa ukukhiqizwa kusetshenziswa izimbiza ezivalwe kahle lapho okusanhlamvu zelayisi kwakufakwa khona ngaphakathi kanye namanzi. Ngokuzungezisa ibhodwe phezu komlilo ukucindezela ngaphakathi kwalo kwanda ngenxa yokuhwamuka kwesicuphoped amanzi. Lapho irayisi selivuthiwe, ibhodwe laligoqwaped esakeni lavuleka, kwabangela ukuqhuma okulawulwayo. Lena kwakuyindlela eyingozi kakhulu, ngoba ngaphandle kwe-valve yokuphepha, kwakunengozi yokuthi yonke into iqhume kungahlosiwe. Le nqubo yathathelwa indawo kakhulu ngemva kweMpi Yezwe II ngemishini esebenza kahle kakhulu ekwazi ukukhiqiza irayisi eligajwe ngokuqhubekayo.
Ama-valve okuqala okuphepha ayeyi-developed ngekhulu le-17 kusukela ama-prototypes ngumsunguli waseFrance UDenis Papin.
Emuva ngalezo zinsuku, ama-valve okuphepha ayesebenza nge-lever kanye ne- isisindo sokulinganisa (esekhona nanamuhla) nakuba, ezikhathini zanamuhla, i ukusetshenziswa kwentwasahlobo esikhundleni isisindo isithandwa futhi ephumelelayo.
Iyini i-valve yokuphepha?
Inhloso enkulu yamavalvu okuphepha ukuvikela izimpilo zabantu ngokuvimbela noma yiluphi uhlelo, olusebenza ngaphansi kwengcindezi ethile, ukuthi lungaqhumisi.
Yingakho kubalulekile ukuqinisekisa ukuthi ama-valve okuphepha asebenza njalo, njengoba engamadivayisi wokugcina ochungechungeni olude olungavimbela ukuqhuma.
Izithombe ezilandelayo zibonisa imiphumela elimazayo yevalvu yokuphepha engalingani, efakwe noma enakekelwa njalo:
umsebenzi we-valve wokuphepha
Isetshenziswa kuphi i-valve yokuphepha?
Yonke indawo izingozi eziphezulu zengcindezi yokusebenza okufanele zidlulwe, ama-valve okuphepha kufanele afakwe. Isistimu ingangena ukucindezela ngokweqile ngezizathu eziningana.
Izizathu eziyinhloko zithinta i ukukhuphuka kwezinga lokushisa okungalawuleki, okubangela ukuphelelwa yisikhathiansioketshezini ngenxa yokwenyuka kwengcindezi, njengomlilo ohlelweni noma ukungasebenzi kahle kwesistimu yokupholisa.
Esinye isizathu, lapho i-valve yokuphepha ikhahlela khona, yi- ukwehluleka yomoya ocindezelweyo noma ukunikezwa kwamandla, ukuvimbela ukufundwa okulungile kwezinzwa endaweni yokulawula.
Ezibucayi futhi izikhathi zokuqala lapho ukuqala uhlelo okokuqala ngqa, noma ngemva kokumiswaped isikhathi eside.
Isebenza kanjani i-valve yokuphepha?
- Ingcindezi esetshenziswa uketshezi ngaphakathi komzimba we-valve isebenza phezu kwediski, ikhiqize amandla F.
- Lapho uF reacUnamandla afanayo namandla asentwasahlobo (isiphethu sifakwe ngaphakathi kwevalvu futhi silungiswe ngaphambilini ngokucindezelwa sibe yinani elinqunywe kusengaphambili), ipulaki iqala ukuphakama iphume endaweni yokuvala yesihlalo kanye process uketshezi luqala ukugeleza (lokhu akulona, noma kunjalo, izinga lokugeleza okuphezulu kwe-valve).
- Kuleli qophelo, ngokuvamile, ingcindezi ekhuphukayo iyaqhubeka nokukhula, okubangela, ngokunyuka okungaba ngu-10% (okuthiwa ukucindezela ngokweqile) uma kuqhathaniswa nokucindezela okubekiwe, ukuphakanyiswa okungazelelwe nokuphelele kwe-valve disc, ekhulula process medium ngokusebenzisa ubuncane besigaba esiphambanayo sevalvu.
- Lapho umthamo we-valve yokuphepha ulingana nezinga lokugeleza okufanele likhishwe, ingcindezi ngaphakathi kwemishini evikelekile ihlala njalo. Uma kungenjalo, uma umthamo we-valve yokuphepha uphakeme kunezinga lokugeleza okufanele likhishwe, ingcindezi ngaphakathi kwemishini ivame ukwehla. Kulesi simo, i-disc, lapho amandla entwasahlobo eqhubeka khona, iqala ukunciphisa ukuphakama kwayo (okungukuthi ibanga phakathi kwesihlalo ne-disc) kuze kube yilapho isigaba sokudlula se-valve sivala (ngokuvamile ukwehla - okubizwa ngokuthi i-blowdown - okulingana 10% ngaphansi kwengcindezi ebekiwe) kanye process uketshezi luyayeka ukuphuma.
Zingaki izinhlobo zamavalvu okuphepha akhona?
Ngokwesimo se amadivaysi okusiza ingcindezi (i-acronym PRD), umehluko oyisisekelo ungenziwa phakathi kwamadivayisi lawo vala futhi kanye nalabo ungaphinde uvale ngemva kokuhlinzwa kwabo. Eqenjini lokuqala sinama-discs aphukile kanye namadivayisi asetshenziswa ngamaphini. Ngokuphambene, iqembu lesibili lihlukaniswe laba ukulayisha okuqondile futhi amadivaysi alawulwayo. Amavalvu okuphepha ayingxenye yamathuluzi avala futhi ngemva kokusebenza kwawo kucushwe isiphethu esisodwa noma ngaphezulu.
Ngaphezu kwalokho, omunye umehluko ungenziwa ngokusho kokusebenza kwama-valve. Njengoba sibona emdwebeni, zikhona ukuphakamisa okugcwele ama-valve okuphepha futhi ngokulinganayo ama-valve okuphepha, abizwa nangokuthi ama-valve okusiza.
i-valve yokuphepha vs i-valve yokusiza
Uyini umehluko phakathi kwama-valve okuphepha nama-valve okusiza?
Amaphayiphu okuphepha kwengcindezi (isifinyezo se-PSV) kanye ama-valve okusiza ukucindezela (i-acronym PRV) bavame ukudideka ngoba banesakhiwo esifanayo nokusebenza. Eqinisweni, womabili ama-valve akhipha uketshezi ngokuzenzakalelayo lapho ingcindezi idlula inani elibekiwe. Ukungezwani kwabo kuvame ukunganakwa, njengoba kunjalo iyashintsha kwezinye izinhlelo zokukhiqiza. Umehluko omkhulu awukho enhlosweni yabo, kodwa ohlotsheni lokusebenza. Ukuya ngaphansistand umehluko phakathi kwakho kokubili, sidinga ukungena ezincazelweni ezinikezwe i-ASME (American Society of Mechanical Engineers) Boiler & Pressure Vessel noma i-BPVC.
The i-valve yokuphepha iyithuluzi lokulawula ukucindezela okuzenzakalelayo eliqhutshwa ukucindezela okungaguquki koketshezi olukhuphuka phezulu kwe-valve, olusetshenziselwa ukufakwa kwegesi noma umusi, “phakamisa ngokugcwele” isenzo.
The impumuzo yokusiza (eyaziwa nangokuthi 'i-valve echichimayo') iyithuluzi elizenzakalelayo lokukhulula ingcindezi eqhutshwa ukucindezela okumile phezulu komfula. It ivula ngokulinganayo lapho ingcindezi idlula amandla okuvula, ngokuyinhloko asetshenziselwa ukusetshenziswa koketshezi.
Ikhwalithi ngaphezu kobuningi
Izesekeli zamavalvu okuphepha
Amavalvu okuphepha anezinsimbi zokulinganisa / zokuvikela
Ama-Bellows ku-valve yokuphepha anemisebenzi elandelayo:
1) ibhalansisa izifutho: iqinisekisa umsebenzi ofanele wevalvu yokuphepha, ukukhansela noma ukukhawulela imiphumela yokucindezela ongemuva, engase ibekwe noma yakheke, ibe yinani elingaphakathi kwemikhawulo ebekiwe yevalvu.
2) isivikelo bellows: ivikela ukuphotha, umhlahlandlela wokuphotha kanye nayo yonke ingxenye engaphezulu yevalvu yokuphepha (okuhlanganisa intwasahlobo) ekuxhumaneni no process uketshezi, okuqinisekisa ukuthi zonke izingxenye ezihambayo ziqotho futhi kusiza ukugwema umonakalo ngenxa yokwenziwa i-cristallization noma i-polymerisation, ukugqwala noma ukuhuzuka kwezingxenye zangaphakathi, okungase kuphazamise ukusebenza okulungile kwevalvu yezokuphepha.
Ukuhlomisa i-valve yokuphephaped nge actuator yomoya
I-actuator ye-pneumatic ivumela ukukhushulwa kwe-disc okuphelele, ukulawulwa kude futhi ngaphandle kokucindezela kokusebenza kwe- process uketshezi.
Ukuhlomisa i-valve yokuphephaped ngedivayisi yokuvimbela i-disc
Besa ingahlomisa ama-valve ayo okuphepha nge-“test gag”, equkethe izikulufu ezimbili, esisodwa esibomvu nesisodwa esiluhlaza. Isikulufu esibomvu, ngokuba side kunesoluhlaza, sivimba ukukhushulwa kwediski, sivimbele i-valve ukuthi ingavuleki.
Ukuhlomisa i-valve yokuphephaped nge-pneumatic valve equipmentped nge-lift indicator
Umsebenzi wesikhombi sokuphakamisa uwukuthola ukuphakamisa idiski, okungukuthi ukuvulwa kwevalvu.
Ukuhlomisa i-valve yokuphephaped nge-vibrations stabilizer
I-stabilizer yokudlidliza inciphisa kube ukuzungeza okuncane nokudlidliza okungenzeka phakathi nesigaba sokukhulula, okwenza i-valve isebenze ngendlela engafanele.
Ama-valve okuphepha aqinile
Ukuze uthole uphawu olungcono phakathi kwe-disc nezihlalo zokuhlala, kungenzeka ukuhlomisa i-valve nge-seal eqinile. Lesi sixazululo senziwa ngemuva kokuhlaziywa koMnyango Wezobuchwepheshe kanye nokucabangela izimo zokuzivocavoca: ingcindezi, izinga lokushisa, imvelo kanye nesimo somzimba process phakathi.
uphawu oluqinile lutholakala ngezinto ezilandelayo: viton ®, NBR, neoprene ®, Kalrez ®, Kaflon™, EPDM, PTFE, PEEK™
Amavalvu okuphepha anejakhethi yokushisisa
Esimeni semidiya ebukekayo kakhulu, enamathelayo noma engaba yikristalu, i-valve yokuphepha ingahlinzekwa enejakhethi yokushisisa, okuyikesi lensimbi engagqwali elishiselwe emzimbeni wevalvu, eligcwaliswe ngoketshezi olushisayo (isimusi, amanzi ashisayo, njll.) ukuze ku qinisekisa i process ukugeleza kwemidiya ngevalvu.
Izindawo zokuvala ezinamagama
Ukuze uthole ukugqwala okungcono nokumelana nokugqoka kwediski nezindawo zokuvala izihlalo, ngesicelo noma ngemuva kwe-Tech. Ukuhlaziywa komnyango, amavalvu okuphepha ahlinzekwa ngediski nesihlalo esinezindawo zokuvala ezinezinhlamvu. Lesi sixazululo sinconywa uma kunengcindezi ephezulu kanye namanani okushisa, imidiya ehlukumezayo, imidiya enezingxenye eziqinile, i-cavitation.
Ukusetshenziswa okuhlanganisiwe kwama-valve okuphepha kanye nediski yokuphuka
Besa® amavalvu okuphepha zifanele ukufakwa kuhlanganiswe ama-discs aphukile ihlelwe phezulu noma phansi kwe-valve. Amadiski okuqhekeka asetshenziswa ezinhlelweni ezinjalo kumele aqinisekiswe ukuthi awahlukani, ngokombono wesakhiwo. Ngakolunye uhlangothi, ku-fluid dynamics, noma iyiphi i-disc yokuqhuma ebekwe phezulu nomfula kufanele ifakwe ngendlela yokuthi:
- amadayamitha agelezayo ediski ephukile makhulu noma alingana nobubanzi obuncane bokungena bokungena kwevalvu yokuphepha
- ukwehla kokucindezela okuphelele (okubalwa kusukela kumthamo wokugeleza okulinganiselwe kuphindaphindwe ngo-1.15) ukusuka endaweni evikelekile yethangi ukuya ku-flange ye-valve yokungena kungaphansi kuka-3% wokucindezela okusebenzayo kwesethi yevalvu yokuphepha. Isikhala phakathi kwe-disc rupture kanye ne-valve kufanele siphume embhobhweni we-1/4" ngendlela yokuqinisekisa ukuthi ukucindezela komkhathi kugcinwa kahle futhi ngokuphepha. Ukuze uthole usayizi olungile wamadiski ngokuya nge-fluid dynamics, i-factor Fd (EN ISO 4126-3 Amakhasi 12. 13) kufanele inakwe, futhi ingathathwa njenge-0. 9.
Ukufakwa kwe-disc rupture upstream ye-valve yokuphepha kunganconywa kulezi zimo ezilandelayo:
- lapho usebenza ngemidiya enolaka, ukuhlukanisa uhlangothi olungenayo lwe-valve ekuxhumaneni okuqhubekayo nalo process uketshezi, ukugwema ukusetshenziswa kwezinto ezibizayo;
- lapho i-metallic seal inikezwa, ukugwema ukuvuza ngephutha koketshezi phakathi kwezindawo zokuhlala/zediski.
Izitifiketi nezimvume
Besa® amavalvu okuphepha zakhiwe, zakhiwe futhi zikhethwa ngokuhambisana nemithetho I-European Directives 2014/68/EU (Okusha PED), 2014 / 34 / EU (ATEX) futhi API 520 526 no-527. Besa® imikhiqizo nayo ivunyiwe ngu RINA® (Besa iqashelwa njengomkhiqizi) futhi DNV GL®.
Phezu kwesicelo Besa inikeza usizo olugcwele lwe ukusebenza kwezivivinyo ngemizimba emikhulu.
Lapha ngezansi ungathola izitifiketi zethu eziyinhloko ezitholwe ama-valve okuphepha.
Besa ama-valve okuphepha CE PED Eqinisekisiwe
The PED isiqondiso sihlinzekela ukumakwa kwemishini yokucindezela nayo yonke into lapho ingcindezi ephezulu evumelekile (PS) ingaphezu kuka-0.5 bar. Lo mshini kufanele ulinganiswe ngokulandelayo:
- izinkambu zokusetshenziswa (izingcindezi, amazinga okushisa)
- izinhlobo zoketshezi olusetshenziswayo (amanzi, igesi, ama-hydrocarbon, njll.)
- isilinganiso sosayizi/ingcindezi edingekayo kuhlelo lokusebenza
Inhloso ye-Directive 97/23/EC iwukuvumelanisa yonke imithetho yezifunda ezingaphansi kwe-European Community mayelana nemishini yokucindezela. Ikakhulukazi, imibandela yokuklama, ukukhiqiza, ukulawula, ukuhlola kanye nenkundla yesicelo ilawulwa. Lokhu kuvumela ukujikeleza kwamahhala kwemishini yokucindezela kanye nezinsiza.
Umyalelo udinga ukuhambisana nezidingo ezibalulekile zokuphepha umkhiqizi okufanele avumelane nazo imikhiqizo kanye nokukhiqiza process. Umkhiqizi unesibopho sokulinganisa nokunciphisa ubungozi bomkhiqizo obekwe emakethe.
Certification process
Inhlangano yenza ukuhlola nokulawula okusekelwe emazingeni ahlukahlukene okuqapha amasistimu ekhwalithi yenkampani. Bese, the PED inhlangano ikhipha izitifiketi ze-CE ze each uhlobo kanye nemodeli yomkhiqizo futhi, uma kunesidingo, nokuqinisekiswa kokugcina ngaphambi kokugunyazwa.
The PED inhlangano bese iqhubeka ngokuthi:
- Ukukhethwa kwamamodeli okuthola isitifiketi/okulebula
- Ukuhlolwa kwefayela lobuchwepheshe kanye nemibhalo yokuklama
- Incazelo yokuhlolwa nomkhiqizi
- Ukuqinisekiswa kwalezi zilawuli kusevisi
- Umzimba ube usukhipha isitifiketi se-CE kanye nelebula yomkhiqizo okhiqiziwe
Besa ama-valve okuphepha CE ATEX Eqinisekisiwe
ATEX - Izisetshenziswa zemikhathi engase ibe neziqhumane (94/9/EC).
“I-Directive 94/9/EC, eyaziwa kangcono ngesifinyezo ATEX, sasetshenziswa e-Italy yi-Presidential Decree 126 of 23 March 1998 futhi sisebenza emikhiqizweni ehloselwe ukusetshenziswa ezindaweni ezingase zibe neziqhumane. Ngokuqala ukusebenza kwe- ATEX I-Directive, i standImikhiqizo ebisebenza ngaphambilini yachithwa futhi kusukela ngomhlaka-1 Julayi 2003 ayivunyelwe ukuthengisa imikhiqizo engahambisani nezinhlinzeko ezintsha.
I-Directive 94/9/EC iyisiqondiso 'entsha' esihloselwe ukuvumela ukuhamba ngokukhululekile kwezimpahla phakathi koMphakathi. Lokhu kufinyelelwa ngokuvumelanisa izimfuneko zokuphepha ezisemthethweni, ngokulandela indlela esekelwe engozini. Futhi ihlose ukuqeda noma, okungenani, ukunciphisa ubungozi obuvela ekusetshenzisweni kwemikhiqizo ethile noma ngokuhlobene nesimo esingase sibe neziqhumane. Lokhu
kusho ukuthi amathuba okuba khona kwesiqhumane esiqhamukayo akumele kubhekwe nje kuphela “ngokukodwa” futhi ngokombono ongashintshi, kodwa zonke izimo zokusebenza ezingase zivele process kumele futhi kubhekwe.
I-Directive ihlanganisa okokusebenza, kungakhathaliseki ukuthi iyodwa noma ihlanganisiwe, ehloselwe ukufakwa “kuzoni” ezibhekwa njengeziyingozi; izinhlelo zokuvikela ezisiza ukumisa noma ukuqukatha ukuqhuma; izingxenye nezingxenye ezibalulekile ekusebenzeni kwemishini noma izinhlelo zokuzivikela; kanye nokulawula kanye nokulungiswa kwemishini yokuphepha ewusizo noma edingekayo ekusebenzeni okuphephile nokuthembekile kwemishini noma izinhlelo zokuvikela.
Phakathi kwezici ezintsha ze-Directive, ezihlanganisa zonke izingozi zokuqhuma kwanoma yiluphi uhlobo (ezikagesi nezingezona ezogesi), okulandelayo kufanele kugqanyiswe:
- Ukwethulwa kwezidingo ezibalulekile zempilo nokuphepha.
- Ukusebenza kokubili kwezimayini nangaphezulu.
- Ukuhlukaniswa kwemishini ngezigaba ngokuya ngohlobo lokuvikela olunikeziwe.
- Ukugadwa kokukhiqiza okusekelwe kumasistimu ekhwalithi yenkampani.
I-Directive 94/9/EC ihlukanisa okokusebenza ngamaqembu amabili amakhulu:
- Iqembu 1 (Isigaba M1 kanye ne-M2): izinto zokusebenza nezinhlelo zokuvikela ezihloselwe ukusetshenziswa ezimayini
- Iqembu lesi-2 (Isigaba 1,2,3): Izinto zokusebenza nezinhlelo zokuvikela ezihloselwe ukusetshenziswa phezulu. (85% wokukhiqizwa kwezimboni)
Ukuhlukaniswa kwendawo yokufaka okokusebenza kuzoba yisibopho somsebenzisi wokugcina; ngakho-ke ngokwendawo enobungozi yekhasimende (isb. indawo engu-21 noma indawo 1) umkhiqizi kuyodingeka ahlinzeke ngempahla efanele leyo ndawo.
Besa ama-valve okuphepha RINA Eqinisekisiwe
RINA ibisebenza njengenhlangano yamazwe ngamazwe enikeza izitifiketi kusukela ngo-1989, njengomphumela oqondile wokuzibophezela kwayo okungokomlando ukuvikela ukuphepha kwempilo yabantu olwandle, ukuvikela impahla kanye nokuvikela umhlaba. marine imvelo, ngokwentshisekelo yomphakathi, njengoba kubekiwe kuMthethosisekelo wawo, kanye nokudlulisa ulwazi lwawo, olutholwe ngaphezu kwekhulu leminyaka, kweminye imikhakha. Njengesikhungo somhlaba wonke sokunikeza izitifiketi, sizibophezele ekuvikeleni impilo yomuntu, impahla kanye nemvelo, ngokwezintshisekelo zomphakathi, nokusebenzisa isipiliyoni saso samakhulu eminyaka kweminye imikhakha.
Uphawu lwe-Eurasian Conformity
The Ukuvumelana kwe-Eurasian umaka (EAC, isiRashiya: I-Евразийское соответствие (ЕАС)) kuwuphawu lwesitifiketi olubonisa imikhiqizo evumelana nayo yonke imithetho yezobuchwepheshe ye-Eurasian Customs Union. Kusho ukuthi i EAC-imikhiqizo emakiwe ihlangabezana nazo zonke izidingo zemithetho ehambisanayo yezobuchwepheshe futhi iphumelele zonke izinqubo zokuhlola ukuhambisana.
Besa ama-valve okuphepha izinkambu eziyinhloko zesicelo
Kusukela 1946
Endle nawe
BESA ibikhiqiza ama-valve okuphepha iminyaka eminingi, ukufakwa okunhlobonhlobo, futhi ulwazi lwethu lunikeza isiqinisekiso esingcono kakhulu esingakhona. Sitadisha ngokucophelela each ngesikhathi sesigaba sokucaphuna, kanye nanoma yiziphi izidingo ezikhethekile noma izicelo, kuze kube yilapho sithola isisombululo esifanele kanye ne-valve efaneleka kakhulu yokufaka kwakho.
