国产公开人成免费_在线A一级毛片免费完整视频_亚洲欧洲日本视频在线_八戒八戒神马影院www_欧美亚洲另类丝袜综合网_99精品無碼人妻一區二區三區_一级做人爰全程视频在线看_精品一区国产VR_欧洲美熟女乱又伦视频免费_黄页免费在线播放

Pressure-sealed globe valve are valves with closing members (discs) moving along the center line of the seat.Depending on this movement of the disc, the variation of the seat orifice is proportional to the disc travel.Due to the relatively short stem opening or closing stroke of the valve, and has a very reliable cut-off function.