OPERATIONAL PRINCIPLES OF SIPHONIC RAINWATER DRAINAGE SYSTEM

Siphonic drainage systems are very simple in principle and all systems operate on the same principle, regardless of model or brand.

The Siphonic drainage system is designed based on the principle of negative pressure in the pipe and takes advantage of the energy due to the height difference between the roof and the drain (storage tank) to enhance drainage.

Picture 1: Siphonic effect experiment

To clearly understand the operating principle of the Siphonic drainage system, we can see an example of the negative pressure phenomenon of the siphon pipe as follows.

Picture 2: Siphonic effect experiment

The system includes 2 water tanks and 1 U-shaped siphon tube. Including:

A: The water tank is in a high position

B: The water tank is in a low position

L1, L2, L3: correspond to each adjacent pipe section.

Arrange as shown in Figure 3, after the Siphon tube is filled with water.

Result: Water from tank A will automatically flow continuously into tank B through the Siphon tube, the process will end when the water level in tank A is lower than the tip of the Siphon tube inside it.

Explanation of the phenomenon: When the Siphon tube is filled with water, the water in pipe section L3 will fall into tank B due to gravity, causing the effect of sucking liquid in pipe sections L1 and L2 to replace the water in section L3 and fall towards tank B This is when negative pressure has appeared inside the pipe, then according to the principle that matter will move from a place of higher pressure to a place of lower pressure, the water behind the water column that has just fallen continues to fall. Filling the position creates negative pressure, linking together to form a flow that cannot be separated in the tube.

Picture  3: Experimental application to the Siphonic rainwater drainage system

Similar to the above experiment, the Siphonic Rainwater Drainage System used the principle of Negative Pressure to make the rainwater drainage process more effective.