97国产看片免费人成视频_卡通动漫日韩一三区_韩国三级中文字幕hd在线_国产成人综合网高清_色偷偷男人的天堂亚洲av_乱爱性全过程免费视频午夜_久久多多屋影院三级_日韩高清在线看AV片_久亚洲第一综合天堂另类专_国产一级男女牲交高潮大片

GFD/FQ multi-function fire-retardant breathing valve produced and sold by Baigang Valve Group is a ventilation device installed on the top of a fixed storage tank.Reduce the evaporation loss of oil and other liquids, control the tank pressure, to prevent the tank from being damaged by overpressure or vacuum.GFD/FQ multi-function fire-retardant breathing valve can also prevent the external flame from entering the role.GFD/FQ multi-function fire-retardant breathing valve is suitable for oil, petrochemical materials and other media, also suitable for cold areas, breathing valve operating pressure before leaving the factory are strictly tested and tested, users are not allowed to change or change the weight of the valve disc.Type of single breath valve, single suction valve, breathing valve, all kinds of structure can be combined with the flame arrestor structure, can also prepare the required nozzles.