Normal water supply:

1、清潔市政生活水從第1級止回閥經過排水器到第二級止回閥出口向用戶供水，第1級止回閥進口高壓水通過高壓軟管進入排水器隔膜上腔，而閣膜下腔與第1級止回閥出口(第二級止回閥進口)相通，由于其存在一定的壓差，推動閥瓣下移，排水器關閉，防止隔斷閥正常供水。

1. Clean municipal domestic water is supplied to users from the first stage check valve to the second stage check valve outlet through the drainer. The high-pressure water at the first stage check valve inlet enters the upper chamber of the drainer diaphragm through the high-pressure hose, and the lower chamber of the diaphragm is connected with the first stage check valve outlet (the second stage check valve inlet). Due to its certain pressure difference, the valve disc is pushed down, and the drainer is closed to prevent the normal water supply of the block valve.

2、當閥門后的管路無用戶，水靜止。如進口壓力保持不變，其前后存在壓差，排水器仍呈關閉狀態。

2. When there is no user in the pipeline behind the valve, the water is still. If the inlet pressure remains unchanged, there is a pressure difference before and after it, and the drain is still closed.

3、如進口壓力下降，一共前后壓差下降到一定值時，彈簧推動閥瓣向上，排水器又開啟泄壓，泄壓到與進口壓力恢復定壓差時，排水器又關閉。

3. If the inlet pressure drops, when the total pressure difference between the front and back drops to a certain value, the spring pushes the valve disc upward, and the drainer opens again for pressure relief. When the pressure is relieved to a constant pressure difference with the inlet pressure, the drainer closes again.

密封失靈時：

In case of seal failure:

1、防污隔斷閥之后管網壓力升高，超過閥前進口壓力時，如第二止回閥密封完好無滲漏，高壓水不會倒流，排水器隔膜上下保持原來壓差，排水器關閉，不泄壓。

1. When the pipe network pressure rises after the anti-pollution isolation valve and exceeds the inlet pressure in front of the valve, if the second check valve is sealed well without leakage, the 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.

2、當第二級止回閥密封破壞產生滲漏，第二級止回閥之前壓力升高，造成排水器一個膜上下壓力并減小，排水器打開，排水泄壓 。

2. When the seal of the second-stage check valve is damaged and leakage occurs, the pressure in front of the second-stage check valve increases, resulting in a decrease in the upper and lower pressure of a membrane of the drainer, and the drainer opens to drain and relieve pressure.

3、此時，如第1級止回閥同時密封被破壞，由于第二級止回閥倒流回的高壓水已泄壓減壓，故不會倒流第1級止回閥。

3. At this time, if the seal of the first stage check valve is damaged at the same time, the high pressure water flowing back from the second stage check valve has been depressurized, so it will not flow back to the first stage check valve.

如供水過程中供水壓力不斷下降，則排水器隔膜上部壓力下降，安全排水器控制彈簧推動閥芯打開排水器排水。當進口壓力下降至零或負壓時，排水器完全打開，水排出，空氣從排水器進真空腔，從而防止產生虹吸倒流現象。上海良工閥門,武漢良工閥門,良工閥門

If the water supply pressure continues to drop during the water supply process, the pressure at the upper part of the drain diaphragm will drop, and the control spring of the safety drain will push the valve core to open the drain to drain. When the inlet pressure drops to zero or negative pressure, the drainer is fully opened, the water is discharged, and the air enters the true cavity from the drainer to prevent siphon backflow. Shanghai Lianggong Valve, Wuhan Lianggong Valve, Lianggong Valve

安裝部位

Installation position

1、自來水管網接入用戶的接戶管水表后面 。

1. The water pipe network is connected to the back of the user's household pipe water meter.

2、生活用水管道上接出非生活用水和排污管，安裝于接出管起端。

2. Non-domestic water and sewage pipes are connected to the domestic water pipe and installed at the beginning of the outlet pipe.

3、生活飲用水水箱的進水管上（水箱底部進水時）。

3. On the inlet pipe of the domestic drinking water tank (when water enters the bottom of the tank).

4、生活飲用水管道上串聯加壓泵時安裝于泵吸水管上。

4. The booster pump is installed on the pump suction pipe when the domestic drinking water pipeline is connected in series.