Yintoni ivalvu?

Ivalvu, ngamanye amaxesha eyaziwa ngokuba yivalvu ngesiNgesi, sisixhobo esisetyenziselwa ukuvimba okanye ukulawula ukuhamba kolwelo olwahlukeneyo. Ivalvu sisixhobo sombhobho esisetyenziselwa ukuvula nokuvala imibhobho, ukulawula indlela yokuhamba, nokuguqula nokulawula iimpawu zendlela yokuhambisa, kubandakanya ubushushu, uxinzelelo, kunye nokuhamba. Ingahlulwa ibe ziivalvu ezivaliweyo, ukujonga iivalvu, ukulawula iivalvu, njalo njalo kuxhomekeke kumsebenzi. Iivalvu zizinto ezilawula ukuhamba kweentlobo ezahlukeneyo zolwelo, kubandakanya umoya, amanzi, umphunga, njl. kwiinkqubo zokuhambisa ulwelo. Iivalvu zesinyithi esitshisiweyo, iivalvu zesinyithi esitshisiweyo, iivalvu zentsimbi engatyiwayo, iivalvu zesinyithi se-chromium molybdenum, iivalvu zesinyithi se-chrome molybdenum vanadium, iivalvu zentsimbi ye-duplex, iivalvu zeplastiki, iivalvu ezingezizo ezenzelwe wena, njl. zimbalwa nje kwiintlobo ezahlukeneyo kunye neenkcukacha zeevalvu.

Ngokuphathelele kwixesha elidlulileyo levalvu

Yonke imihla yobomi bethu ichaphazeleka kukusetyenziswa kweevalvu. Sisebenzisa iivalvu xa sivula itephu ukuze sifumane amanzi okusela okanye isixhobo sokucima umlilo ukuze sinkcenkceshele izityalo. Ukuhlala ixesha elide kweevalvu ezininzi kungenxa yokudibanisa okuntsonkothileyo kwemibhobho.

Uphuhliso lweenkqubo zemveliso yemizi-mveliso kunye nophuhliso lweevalvu zidibene ngokusondeleyo. Ilitye elikhulu okanye isiqu somthi sinokusetyenziselwa ukunqanda ukuhamba kwamanzi okanye ukutshintsha indlela ahamba ngayo kwihlabathi lamandulo ukuze kulawulwe ukuhamba kwemilambo okanye imilambo. ULi Bing (iminyaka yokuzalwa nokufa engaziwa) waqala ukumba amaqula etyuwa kwiChengdu Plain ekupheleni kwexesha leMfazwe yaMazwe ukuze afumane ityuwa enetyuwa neqhotsiweyo.

Xa kukhutshelwa ityuwa, iqhekeza elincinci le-bamboo lisetyenziswa njengesilinda sokukhupha ityuwa efakwa kwisingxobo kwaye inevalvu yokuvula nokuvala ezantsi. Isakhelo esikhulu somthi sakhiwe phezu komthombo, kwaye isilinda enye inokutsala ityuwa exabisa iibhakethi ezininzi. Emva koko ityuwa ifunyanwa kusetyenziswa ivili lombumbi kunye nevili lokukhupha i-bamboo ebhakedeni. Yifake emthonjeni ukuze utsale ityuwa yokwenza ityuwa, kwaye ufake ivalvu yomthi kwelinye icala ukuze uthintele ukuvuza.

Phakathi kwezinye izinto, iimpucuko zaseYiputa naseGrisi zaphuhlisa iintlobo ezininzi zeevalvu ezilula zokunkcenkceshela izityalo. Nangona kunjalo, kuyavunywa ngokubanzi ukuba amaRoma amandulo adala iinkqubo zokunkcenkceshela amanzi ezintsonkothileyo zokunkcenkceshela izityalo, esebenzisa iivalvu ze-cock kunye ne-plunger kunye neevalvu ezingabuyiyo ukuthintela amanzi ukuba abuye umva.

Uninzi lweendlela zobugcisa zikaLeonardo da Vinci zexesha leRenaissance, kuquka iinkqubo zokunkcenkceshela, imijelo yokunkcenkceshela, kunye nezinye iiprojekthi ezibalulekileyo zenkqubo ye-hydraulic, zisasebenzisa iivalvu.

Kamva, njengoko iteknoloji yokushisa kunye nezixhobo zokulondoloza amanzi zazihambela phambili eYurophu,imfuno yeevalvuNgenxa yoko, kwaveliswa iivalvu zeplagi zekopolo nezealuminiyam, kwaye iivalvu zafakwa kwinkqubo yesinyithi.

Uguquko lwezeMishini kunye nembali yanamhlanje yeshishini leevalvu inembali efanayo eye yanda ngakumbi ngokuhamba kwexesha. Injini yokuqala yorhwebo yomphunga yadalwa ngo-1705 nguNewcomman, owathi wacebisa nemigaqo yolawulo lokusebenza kwenjini yomphunga. Ukuveliswa kwenjini yomphunga nguWatt ngo-1769 kwaphawula ukungena ngokusesikweni kwevalvu kwishishini loomatshini. Iivalvu zeplagi, iivalvu zokhuseleko, iivalvu zokujonga, kunye neevalvu zebhabhathane zazisetyenziswa rhoqo kwiinjini zomphunga.

Izicelo ezininzi kwishishini leevalvu zisuka ekudalweni kwenjini yomphunga nguWatt. Iivalvu zesilayidi zaqala ukubonakala kwinkulungwane ye-18 neye-19 ngenxa yokusetyenziswa ngokubanzi kweenjini zomphunga ngabembi bemigodi, abatshisi, abenzi beempahla, abenzi boomatshini, kunye namanye amashishini. Ukongeza, wadala isilawuli sokuqala sesantya, esakhokelela ekuthandeni okukhulu kulawulo lokuhamba kolwelo. Uphuhliso olubalulekileyo kuphuhliso lweevalvu kukuvela okulandelayo kweevalvu zeglobe ezineziqu ezinemisonto kunye neevalvu zesango le-wedge ezineziqu ezinemisonto ye-trapezoidal.

Uphuhliso lwezi ntlobo zimbini zeevalvu ekuqaleni lwanelisa iimfuno zolawulo lokuhamba kwamanzi kunye neemfuno zamashishini amaninzi zokuphucula uxinzelelo kunye nobushushu beevalvu rhoqo.

Iivalvu zebhola okanye iivalvu zeplagi ezingqukuva, ezisusela kuyilo lukaJohn Wallen noJohn Charpmen ngenkulungwane ye-19 kodwa ezingazange zenziwe ngelo xesha, ngokomthetho zazifanele ukuba ziivalvu zokuqala kwimbali.

Umkhosi wamanzi waseMelika wawungumxhasi wokuqala wokusetyenziswa kweevalvu kwiinqanawa ezingaphantsi komhlaba emva kweMfazwe Yehlabathi yesiBini, kwaye uphuhliso lwevalvu lwenziwa ngokukhuthazwa ngurhulumente. Ngenxa yoko, kuye kwenziwa iiprojekthi ezininzi ezintsha ze-R&D kunye namanyathelo kwicandelo lokusetyenziswa kweevalvu, kwaye imfazwe ikhokelele ekuphuculeni ubuchwepheshe obutsha beevalvu.

Uqoqosho lwamazwe aphuhlileyo kwezoshishino lwaqala ukuchuma nokukhula olunye emva kolunye ngeminyaka yoo-1960. Iimveliso ezivela kwilizwe elalisakuba yiNtshona Jamani, iJapan, i-Itali, iFransi, i-United Kingdom, kunye namanye amazwe zazinomdla wokuthengisa iimpahla zazo kwamanye amazwe, kwaye ukuthunyelwa kwamanye amazwe koomatshini nezixhobo ezipheleleyo yikona okwabangela ukuthunyelwa kwamanye amazwe kweevalvu.

Iikoloni zangaphambili zafumana inkululeko nganye nganye phakathi kokuphela kweminyaka yoo-1960 nasekuqaleni kweminyaka yoo-1980. Benomdla wokuphuhlisa amashishini abo asekhaya, bathenga oomatshini abaninzi, kuquka neevalvu. Ukongeza, ingxaki yeoyile yabangela ukuba amazwe ahlukeneyo avelisa ioyile enze utyalo-mali olukhulu kwicandelo leoyile elinengeniso enkulu. Ixesha lokukhula okukhulu kwimveliso yeevalvu zehlabathi, urhwebo, kunye nophuhliso laqala ngenxa yezizathu ezininzi, nto leyo eyaqhubela phambili ukukhula kweshishini leevalvu.