The principle of siphon roof rainwater system depends on the design of special rainwater hopper to separate gas from water and make rainwater riser full. When the water in the riser reaches a certain capacity, the siphon effect will occur. In the process of rainfall, due to the continuous siphon effect, the whole system can discharge rainwater from the roof surprisingly quickly.

Characteristics of siphon roof drainage system

At the beginning of rainfall, the siphon drainage system works in the same way as the gravity drainage system under the condition that the height of rainwater on the roof does not exceed the height of rainwater bucket.

With the continuous rainfall, when the height of rainwater on the roof exceeds the height of rainwater hopper, the scientifically designed anti-vortex rainwater hopper is adopted. By controlling the flow rate of rainwater entering the rainwater hopper, the flow pattern is adjusted and the vortex is reduced, thus greatly reducing the amount of air entrained by rainwater entering the drainage system and making the drainage pipeline in the system in a full circulation state. Using the height of the building roof and the potential energy of rainwater, the siphon effect is formed when rainwater continuously flows into the rainwater riser and falls, and the maximum negative pressure appears in the pipeline. Roof rainwater is discharged to the outdoor at high speed under the suction of negative pressure in the pipeline.

2. The difference between siphon type and gravity type and ground rainwater drainage system.

In the siphon roof rainwater drainage system, the drainage pipe is designed according to the full flow and pressure state, so the rainwater suspension pipe in the siphon drainage system can be laid without slope. At the same time, when the siphon effect occurs, the water velocity in the pipeline is very high, so the system has good self-cleaning effect. However, the design calculation of gravity drainage is not based on full flow, and the laying slope of rainwater suspension pipe should not be less than 0.005.

The drainage capacity of siphon drainage system is much larger than that of gravity drainage system with the same caliber, that is to say, excluding the same rainwater flow, the diameter of drainage pipe of siphon drainage system is smaller than that of gravity drainage system.

Siphon drainage system is essentially a multi-bucket pressure flow rainwater drainage system. Therefore, compared with the gravity drainage system, the buried pipes are obviously reduced.