Waalku waa qalab ama shay dabiici ah oo nidaamiya, hagaya ama koontaroolaya qulqulka dareeraha (gaasaska, dareeraha, adkaha dareeraha ah, ama slurries) isagoo furaya, xidhaya, ama qayb ahaan xannibaya marino kala duwan. Valves waa farsamo ahaan ku habboon, laakiin inta badan waxaa looga hadlaa sidii qayb gaar ah. Waalka furan, dareeruhu wuxuu u socdaa jihada cadaadiska sare ilaa cadaadiska hoose. Eraygu waxa uu ka yimid valva-ka Laatiinka, oo ah qaybta dhaqaaqda ee albaabka, marka loo eego volvere, to turn, roll.

Kan ugu fudud, oo aad u qadiimi ah, waalka waa fudfudud si xor ah ugu lulan kaas oo hoos u rogmado si uu u xannibo dareeraha (gaaska ama dareeraha) ee hal jihada, laakiin waxaa kor u riixaya qulqulka laftiisa marka qulqulku u socdo jihada ka soo horjeeda. Tan waxa loo yaqaan waalka hubinta, maadaama ay ka hortagto ama “hubiso” socodka hal jiho. Dabaqadaha kontoroolka casriga ah ayaa laga yaabaa inay nidaamiyaan cadaadiska ama qulqulka hoose waxayna ku shaqeeyaan habab otomaatig ah oo casri ah.

Valves waxay leeyihiin faa'iidooyin badan, oo ay ku jiraan xakamaynta biyaha ee waraabka, isticmaalka warshadaha ee hababka xakamaynta, isticmaalka guryaha sida shid/damida iyo xakamaynta cadaadiska saxanka iyo dharka dhaqida iyo qasabadaha guriga. Xataa daasadaha lagu buufiyo aerosol-ka waxay leeyihiin waal yar oo laga dhex dhisay. Valves sidoo kale waxaa loo isticmaalaa qaybaha ciidamada iyo gaadiidka. Shabakadda HVAC iyo socodka hawada kale ee hawada ku dhow, valves ayaa beddelkeeda loogu yeeraa dampers. Nidaamyada hawada ciriiriga ah, si kastaba ha ahaatee, valves waxaa loo isticmaalaa nooca ugu caansan ee ah valves balls.
Codsiyada

Valves waxa laga helaa habsocod kasta oo warshadeed, oo ay ku jiraan habaynta biyaha iyo bulaacada, macdanta, tamarta, farsamaynta saliidda, gaaska iyo batroolka, wax soo saarka cuntada, kiimikaad iyo caagadaha iyo qaybo kale oo badan.

Dadka ku nool wadamada horumaray waxay nolol maalmeedkooda ku isticmaalaan valves, oo ay ku jiraan tuubooyinka biyaha, sida qasabadaha biyaha tuubada, makiinada gaaska lagu xakameeyo makiinadaha, mashiinada yar yar ee lagu rakibay mashiinada dharka iyo makiinada weel dhaqida, aaladaha badbaadada ee lagu rakibay nidaamka biyaha kulul, iyo baabuurka poppet matoorada.

Dabeecadda waxaa jira valves, tusaale ahaan hal-jidka valves ee xididdada xakameynaya wareegga dhiigga, iyo valvesyada wadnaha ee xakameynaya qulqulka dhiigga ee qolalka wadnaha iyo ilaalinta habka saxda ah ee bamgareynta.

Valves waxaa laga yaabaa in lagu shaqeeyo gacanta, ha ahaato gacan, kabaal, baalle ama giraangire. Valves waxa kale oo laga yaabaa inay si toos ah u noqdaan, oo ay dhaqaajiyaan isbeddelada cadaadiska, heerkulka, ama socodka. Isbeddelladani waxay ku dhaqmi karaan diaphragm ama bistoon taas oo iyaduna kicisa waalka, tusaaleyaasha nooca waalka ah ee inta badan la helo waa valves badbaado oo ku rakiban nidaamyada biyaha kulul ama kuleyliyeyaasha.

Nidaamyo kontorool oo kakan oo isticmaalaya valves u baahan kontorool otomaatig ah oo ku salaysan gelinta dibadda (tusaale, nidaaminta qulqulka tuubada oo beddeleysa barta go'an) waxay u baahan tahay hawl-wadeen. Dhaqdhaqaaq-geliyaha ayaa garaaci doona waalka iyadoo ku xiran gelinta iyo dejinta, taasoo u oggolaanaysa in valve si sax ah loo dhigo, oo u oggolaanaya in la xakameeyo shuruudo kala duwan.
Kala duwanaansho

Valves way kala duwan yihiin qaab ahaan iyo codsi ahaan. Cabbirrada[aan madmadow] caadi ahaan waxay u dhexeeyaan 0.1 mm ilaa 60 cm. Tuubooyinka gaarka ah waxay yeelan karaan dhexroor ka badan 5 mitir.[waa kee?]

Kharashyada Valve-ku waxay u dhexeeyaan valves fudud oo raqiis ah oo la tuuri karo ilaa valves khaas ah kuwaas oo ku kacaya kumanaan doolarka Maraykanka ah dhexroorka waalka.

Tuubooyinka la tuuri karo waxaa laga yaabaa in laga helo alaabta guriga ee caadiga ah oo ay ku jiraan matoorada yar-yar iyo gasacadaha hawada.

Isticmaalka caadiga ah ee ereyga valve waxaa loola jeedaa valves poppet ee laga helo inta badan mishiinnada gubashada gudaha ee casriga ah sida kuwa ku jira inta badan baabuurta shidaalka ku shaqeeya kuwaas oo loo isticmaalo in lagu xakameeyo qaadashada isku dhafka shidaalka iyo hawo-qaadista gaaska qiiqa.
Noocyada

Valves waa kala duwan yihiin waxaana laga yaabaa in loo kala saaro dhowr nooc oo aasaasi ah. Valves sidoo kale waxaa lagu kala saari karaa sida loo dhaqaajiyo:

Haydarooliga
Pneumatic
Buugga
Solenoid valve
Matoorka