Indastering ea sejoale-joale ea taolo ea phallo, li-valve tsa ho hlahloba li-wafer li ntse li tsebahala haholo ka lebaka la moralo oa tsona o kopaneng, bonolo ba ho kenya le litšenyehelo tse tlase tsa ho qala le tsa tlhokomelo ha li bapisoa le licheke tsa khale tsa flanged.BVMC e fana ka li-valve tsa ho hlahloba poleiti e le 'ngoe le li-valve tse nang le lisebelisoa tse fapaneng.