Sekudlule iminyaka engaphezu kwengu-50 selokhu kwethulwa ivalvu yebhabhathane e-eccentric kathathu, futhi ibilokhu ithuthukiswa njalo eminyakeni engu-50 edlule. Ukusetshenziswa kwamavalvu ebhabhathane kuye kwahlanganisa izimboni eziningi. Ivalvu yebhabhathane yokuqala isetshenziselwa kuphela ukuvimba nokuxhuma imithombo yamanzi. Umklamo we-eccentric kathathu uthuthukisa umsebenzi wevalvu yebhabhathane. Isibe ngelinye lamavalvu asebenza kahle kakhulu ngaphansi kwezimo ezinzima kakhulu endaweni yenqubo ebalulekile emishinini yamapayipi ezimboni zezimboni.

Njengoba igama lisikisela, ama-offset amathathu azimele aklanywe njengama-valve. Ukungaguquguquki kathathu kusho:

• I-Offset 1

Umgodi ubekwa ngemuva kwendawo yokuvala ukuze kuhlinzekwe indlela yokuhlala eqhubekayo.

• I-Offset 2

Ishafti ibekwa ohlangothini olulodwa lomugqa ophakathi wepayipi/valvu ukuze kuqedwe ukungqubuzana phakathi kwesivalo nesihlalo

• I-Offset 3

Imigqa ephakathi yesihlalo kanye nekhoni yesivalo ithambekele maqondana nomugqa ophakathi wepayipi/ivalvu. Lokhu kususwa kwesithathu kuqeda ngokuphelele ukuhlikihla. Le engela yekhoni, kanye nama-offset amabili e-shaft angavamile, ivumela idiski ukuthi ivale isihlalo ngaphandle kokungqubuzana.

Lo mklamo wesihlalo uphinde uvumele ukuvalwa okufanayo, ngaleyo ndlela ukuvalwa okuqinile ekwakhiweni kwesihlalo sensimbi. Lo mklamo uyindlela engabizi kakhulu, ephansi ye-torque (elula ukuyenza ngokuzenzakalelayo), kunezinye izinhlobo zamavalvu ahlala ngensimbi.

Ama-offset amathathu ngokuvamile asetshenziswa ezinhlelweni ezifana nomusi ocindezelayo ophezulu (ngaphezu kwe-150 PSI), umusi oshisayo kakhulu, amagesi okushisa okuphezulu namafutha, ukusetshenziswa kokushisa okuphezulu kuhle kulolu hlobo lwe-valve ngoba isihlalo sensimbi siyadingeka phezu kwesihlalo esithambile.