30mm per second. The diversion tube (center tube) is used in the sedimentation tank. Water enters the tank from top to bottom through the inlet pipe in the center of the tank (the flow rate in the pipe should be less than 30mm per s). An umbrella-shaped baffle is set under the pipe to make the wastewater evenly distributed in the tank. The entire water-passing section of the rear edge rises slowly (generally 0.5-0.7mm per s for domestic sewage.