The HS41X-16-A anti fouling block valve is a safety device used to prevent backflow pollution in domestic drinking water pipelines. It is a novel valve developed by our factory with advanced foreign technology, which is safe, reliable, and prevents backflow pollution of drinking water. It ensures the hygiene and safety of domestic drinking water.

　　Product Structure:

The HS41X-A safety type anti fouling block valve is composed of a drain valve added between two check valves. The upper chamber of the drain is connected to the inlet end of the stage check valve with a high-pressure hose. The secondary check valve mainly consists of a valve body, valve cover, valve disc, sealing gasket, spring, etc. The drain mainly consists of valve body, valve cover, diaphragm, valve disc, sealing plate, valve core, valve seat, spring, etc. The HS41X-16 ordinary anti fouling block valve is composed of multiple check seals connected in series. (As shown in the following figure):

　　working principle:

The HS41X-16 ordinary anti fouling block valve is composed of multiple check seals connected in series. When one of the seals is damaged, the other two still function as seals to prevent backflow. But when all three check seals are damaged at the same time, the check function is lost.

The HS41X-16-A safety type anti fouling isolation valve is equipped with a drain in the middle on the basis of the ordinary type, so that even if the seals of both check valves are damaged at the same time, the others can still prevent backflow pollution.

(1) Normal water supply:

① Clean municipal domestic water is supplied to users from the level check valve through the drain to the outlet of the second level check valve. The high-pressure water at the inlet of the level check valve enters the upper chamber of the drain diaphragm through a high-pressure hose, while the lower chamber of the diaphragm is connected to the outlet of the level check valve (inlet of the second level check valve). Due to a certain pressure difference, it pushes the valve disc downward, closes the drain, and prevents the block valve from supplying water normally;

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

c. When the inlet pressure drops and the pressure difference between the front and rear reaches a certain value, the spring pushes the valve disc upwards, and the drain opens again to release pressure. When the pressure drops to a certain pressure difference with the inlet pressure, the drain closes again.

(2) When the seal fails:

When the pressure in the pipeline increases after the anti fouling isolation valve and exceeds the inlet pressure in front of the valve, if the second check valve seal is intact and there is no leakage, high-pressure water will not flow back, and the pressure difference between the upper and lower parts of the drain diaphragm will be maintained. The drain will close without pressure relief. When the seal of the second level check valve is damaged and leaks, the pressure before the second level check valve increases, causing the upper and lower pressure of the drainage membrane to decrease. The drainage opens and the drainage is depressurized; At this time, if the sealing of the first stage check valve is also damaged, 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.

(3) If the water supply pressure continuously decreases during the water supply process, the pressure on the upper part of the drain diaphragm will decrease, and the safety drain control spring will push the valve core to open the drain for drainage. 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, thereby preventing siphon backflow.

　　Technical parameters:

Operating pressure: 1.6Mpa

Medium used: Water

Medium temperature:<=60 ℃

　　Main appearance and installation dimensions:

　　Installation requirements and schematic diagram:

① Anti fouling isolation valves must be installed horizontally, in a clean environment with sufficient maintenance space. The outlet of the safety drain or air barrier should be at least 300mm above the ground and not submerged by water or debris.

② Drainage facilities should be installed in the installation area.

③ A gate valve (butterfly valve) filter and rubber flexible joint (or expansion joint) should be installed in front of the valve, and a gate valve (butterfly valve) should be installed behind the valve. The schematic diagram is as follows: (Figure 3, Figure 4)

　　Installation location:

① Connect the tap water network to the user's water meter behind the household pipe

② Non domestic water and sewage pipes are connected to the domestic water pipeline and installed at the starting end of the outlet pipe.

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

④ When a booster pump is connected in series on a drinking water pipeline, it is installed on the pump suction pipe.