（1） Process and structure of gravity siphon valve free integrated water purification equipment

Its process and internal structure of the tank body are the same as those of the fully hydraulic integrated water purification equipment, except for the different backwashing method on the periphery. Combined with a dosing device, pipeline mixer, disinfection device, and backwashing siphon valve free pipeline, it becomes a complete set of conventional process small and medium-sized pressure purification treatment equipment, completing the entire treatment process of domestic drinking water. The effluent quality meets the requirements of GB5749-2006 standard, and the water purification time is about 25-30 minutes. Suitable for small and medium-sized rural drinking water safety projects.

（2） Design points and installation precautions for gravity siphon valve free integrated water purification equipment

(1) Water source requirements: There should be a certain drop between the water source and the equipment, greater than 6m and less than 30m.

（3） Working principle of gravity siphon valve free integrated water purification equipment

At the beginning of filtration, the water level difference (H1) between the siphon riser C and the flushing water tank D is the initial head loss of filtration. As filtration progresses, the filter layer continuously intercepts suspended solids, and the filtration head loss gradually increases, causing the water level in the siphon riser to gradually rise. When the water level rises to the point where water flows down from the siphon auxiliary pipe opening C through the auxiliary pipe, the vacuum in the siphon tube is increased by the suction and trapping effect of the water flow, and all the air in the siphon tube is taken away, forming a continuous siphon water flow. At this point, the pressure on the upper part of the filter layer drops sharply, promoting the water in the flushing water tank to enter the siphon tube in the opposite direction of the filtered water. As a result, the filter material is backwashed, and the flushing wastewater flows from the drainage well to the sewer. During the flushing process, the water level in the water tank gradually decreases. When the water level drops below the siphon breaker, the pipe opening is connected to the atmosphere, the siphon is broken, the flushing is completed, and the filtration starts again.

（4） Technical parameters of gravity siphon valve free integrated water purification equipment:

Backwash intensity 10-15L/m2 · s; Filtration rate 6-10m/h; Work pressure: 0.04-0.3MPa

（5） Gravity siphon valve free integrated water purification equipment Scope of application:

The integrated water purification equipment is suitable for water sources with a turbidity of around 100NTU throughout the year and no more than 1500NTU instantaneously. Other indicators meet the requirements of Class II water in the Surface Water Environmental Quality Standards.

（6） Gravity siphon valve free integrated water purification equipment for effluent quality

The effluent quality of the gravity siphon valve free integrated water purification equipment meets the requirements of the "Sanitary Standards for Drinking Water" (GB5749).