产品描述 Product Description

进口过滤式倒流防止器是由两级止回系统及一个排水泄压系统组成。上腔与第一级止回系统进口端连接，第一、二止回阀系统主要由阀体、进水口接头、阀瓣、密封垫、弹簧等组成。排水泄压系统主要由阀盖、膜片、阀轴、密封垫、排水口、弹簧、空气阻隔器组成。retz The imported filter type backflow preventer is composed of a two-stage check system and a drainage and pressure relief system. The upper chamber is connected to the inlet end of the first stage check system, and the first and second check valve systems are mainly composed of valve bodies, inlet joints, valve discs, sealing gaskets, springs, etc. The drainage and pressure relief system mainly consists of a valve cover, diaphragm, valve shaft, sealing gasket, drainage port, spring, and air barrier

性能参数 performance parameter

工作原理Working principle

当生活用水从第一级止回系统经过排水器到第二级止回系统出口向用户供水，第一止回系统进口高压水进入排水器隔膜上腔使排水器关闭，保证隔膜下腔与第一级止回阀正常供水。▲当阀后管路无用户，水静止，如进口压力不变，因前后存在压差，所以排水器仍呈关闭状态。▲当供水过程中供水压力不断下降，其前后压差下降到一定值时，则排水器隔膜上部压力下降，弹簧推动阀轴向上，排水器开启泄压，泄压到与进口压力恢复一定压差值时，排水器关闭。当进口压力下降至零或负压时，排水器完全打开，水排出，空气从排水器进入真空腔，从而防止产生虹吸倒流现象。▲当防污隔断阀之后管网压力升高，超过阀前进口压力时，如第二止回阀密封完好无渗漏，高压水不会倒流，排水器隔膜上下保持原来压差，排水器关闭，不泄压，如第二止回阀密封破坏产生泄漏，第二止回阀之前压力升高，造成排水器隔膜上下压差减小，排水器打开排水泄压，此时如第一止回阀密封同时破坏，由于第二止回阀倒流回的高压水己泄压减压，也不会倒流回第一止回阀。

When domestic water is supplied to users from the first level check system through the drain to the outlet of the second level check system, high-pressure water from the inlet of the first check system enters the upper chamber of the drain diaphragm to close the drain, ensuring normal water supply between the lower chamber of the diaphragm and the first level check valve. When there is no user in the pipeline behind the valve and the water is still at rest, if the inlet pressure remains unchanged, the drain will still be closed due to the pressure difference between the front and rear. When the water supply pressure continuously decreases during the water supply process, and the pressure difference before and after it drops to a certain value, the pressure on the upper part of the drain diaphragm decreases. The spring pushes the valve axially upwards, and the drain opens to relieve pressure. When the pressure is relieved to a certain pressure difference with the inlet pressure, the drain closes. When the inlet pressure drops to zero or negative pressure, the drain is fully opened, water is discharged, and air enters the vacuum chamber from the drain to prevent the occurrence of siphon backflow. When the pressure of the pipeline network increases after the anti pollution isolation valve, exceeding the inlet pressure in front of the valve, if the second check valve is sealed well without leakage, high-pressure water will not flow back, the original pressure difference between the upper and lower parts of the drain diaphragm is maintained, and the drain is closed without pressure relief. If the seal of the second check valve is damaged, leakage occurs. The pressure before the second check valve increases, causing a decrease in the pressure difference between the upper and lower parts of the drain diaphragm, and the drain is opened to discharge pressure, At this point, if the seal of the first check valve is damaged at the same time, the high-pressure water flowing back from the second check valve has already been depressurized and will not flow back to the first check valve.

进水状态 Water inlet status

止回状态 Check state

排污状态 Pollutant discharge status

主要零件与材质（Major part material）

安装示意图

安装部位

接入用户自来水管网的水表后面。

生活用水管道上接出的非生活饮用水和排污管，安装在接出管起始端。

生活饮用水水箱的进水管上（水箱底部进水时）。

生活饮用水管道上串联加压时，安装在泵的吸水管道上。