Small size , light weight and easy maintenance the above series of valves can be used as device to cut-off or regulate the flow in various medium pipes .through selection different materials of disc and seal seat ,as well as the pinless connection between disc and stem , the valve can be applied to worse conditions , such as desulphurization vacuum , sea water desalinization . lug butterfly valve allow downstream pipelines and equipments online repair , and it  can be on pipe ends as exhaust valve .