Pob li qub tau tshwm sim hauv xyoo 1950. Nrog rau txoj kev loj hlob sai ntawm kev tshawb fawb thiab thev naus laus zis, kev txhim kho txuas ntxiv ntawm cov txheej txheem tsim khoom thiab cov qauv tsim khoom, lawv tau tsim sai sai rau hauv hom valve loj hauv tsuas yog 50 xyoo. Nyob rau hauv industrialized Western lub teb chaws, kev siv cov pob li qub tau nce zuj zus txhua xyoo.
Pob li qub feem ntau yog siv rau hauv cov kav dej los txiav tawm, faib, thiab hloov cov dej ntws ntawm qhov nruab nrab. Lawv tuaj yeem kaw nruj nreem nrog tsuas yog 90 degree kev sib hloov thiab lub zog hloov me me. Pob li qub yog qhov zoo tshaj plaws rau kev siv los ua cov keyboards thiab kaw-off li qub.
Vim lub fact tias pob li qub feem ntau siv roj hmab, nylon, thiab polytetrafluoroethylene li lub rooj sealing nplhaib cov ntaub ntawv, lawv siv kub yog txwv los ntawm lub rooj sealing nplhaib khoom. Qhov kev txiav tawm ntawm lub pob valve yog ua tiav los ntawm nias lub pob hlau tiv thaiv lub rooj zaum hauv lub rooj zaum hauv qab ntawm qhov kev txiav txim ntawm qhov nruab nrab (floating pob valve). Nyob rau hauv ib qho kev sib cuag siab, lub valve lub rooj sealing nplhaib undergoes elastic-yas deformation nyob rau hauv cov cheeb tsam. Qhov deformation no tuaj yeem them nyiaj rau qhov raug tsim thiab qhov roughness ntawm lub pob, kom ntseeg tau tias kev sib khi ntawm lub pob valve.
Vim lub fact tias lub rooj zaum valve sealing nplhaib ntawm lub pob valve feem ntau yog ua los ntawm cov yas, thaum xaiv cov qauv thiab kev ua tau zoo ntawm lub pob valve, qhov hluav taws kub tsis kam thiab kev tiv thaiv hluav taws ntawm lub pob valve yuav tsum tau txiav txim siab, tshwj xeeb tshaj yog nyob rau hauv cov tuam tsev xws li petroleum, tshuaj, thiab metallurgy. Thaum siv cov pob li qub hauv cov khoom siv thiab cov kav dej nrog cov xov xwm hluav taws xob thiab cov khoom tawg, kev tiv thaiv hluav taws thiab kev tiv thaiv hluav taws yuav tsum tau saib xyuas ntau dua.
