久久99国产综合精品无码_亚洲日韩欧美视频_欧美国产自偷自偷在线视频_欧美亚洲综合日产_欧美狂野性视频网站_高清无码a免费在线播放_亚洲国产最新视频在线观看_china中国对白刺激大豆_精品国产亚洲一区_校花被扒衣吸乳羞羞漫画

Overview:The built-in anti backflow device in the pipe is composed of a stainless steel shell, synthetic rubber membrane flap, fasteners, etc. The synthetic rubber membrane flap tightly adheres to the inner wa

Overview:The built-in anti backflow device in the pipe is composed of a stainless steel shell, synthetic rubber membrane flap, fasteners, etc. The synthetic rubber membrane flap tightly adheres to the inner wall of the pipeline in the absence of water flow, preventing any fluid from flowing from downstream to upstream. When the pressure inside the pipeline reaches a certain level, the membrane flap will open under the action of pressure, causing it to open and allow the fluid to flow.