DLB Gravel Gravity Self-Draining Valveless Filter

Operating Principle
Raw water is fed into the filter tank through the inlet pipe, filtered through the filter layer from top to bottom. Clean water is then injected into the storage tank through a connecting pipe. Once the tank is full, the water flows through the outlet pipe into the clear water tank. The filter layer continuously retains suspended matter, gradually increasing the resistance. This causes the water level in the siphon pipe to rise continuously. When the water level reaches the mouth of the siphon auxiliary pipe, water falls from it, utilizing the suction pipe to remove air from the siphon下降 pipe. When a certain vacuum level is reached, siphon action occurs. At this point, water in the pipe flows from bottom to top through the filter layer, backwashing the filter material. When the water level in the backwashing tank drops to the siphon destruction pipe, air enters the siphon pipe, disrupting the siphon action. The filter tank backwashing is complete, and the cycle proceeds to the next stage of operation.

Application Scope
Gravity-fed valveless filters are widely used in surface water purification, groundwater iron and manganese removal, bypass filtration of circulating water, removal of suspended solids from production wastewater, post-treatment filtration after biochemical treatment and secondary sedimentation pond for organic wastewater, and filtration of indoor swimming pool water. They are a type of water treatment equipment.
Currently, our factory produces two major series of valveless filters: one with square CBL-Ⅱ filter tanks, and the other with round DLB-Ⅱ filter tanks. The CBL-Ⅱ and DLB-Ⅱ series valveless filters operate automatically without valves, relying on hydraulic force for water intake, outlet, flushing, and drainage. They are cost-effective, easy to manage, safe and reliable, and feature automated operation. The equipment is integrated, with the water intake tank, filter, and backwashing tank assembled into a compact structure. Users only need to construct the equipment foundation and connect the intake and outlet pipes as per requirements to start operation. Additionally, all series of these filters are equipped with lids, providing good hygiene and protection, allowing for outdoor installation. Compared to reinforced concrete filter tanks, they have a lower weight and use asphalt sand flexible foundations.

DLB-Ⅱ Filter Model Specifications and Technical Parameters