Working Principle
       The raw water is sent into the filter tank through the water inlet pipe, and is filtered from top to bottom through the filter layer. The clean water is injected into the water storage tank from the connecting pipe for storage. After the water tank is full, the water enters the clean pool through the outlet pipe. The filter layer continuously intercepts suspended solids, causing the resistance of the filter layer to gradually increase, thus causing the water level in the siphon to continue to rise. When the water level reaches the mouth of the siphon auxiliary pipe, the water falls from the pipe and takes away the air in the siphon down pipe through the air suction pipe. When the vacuum reaches a certain value, the siphon effect occurs. At this time, the water in the water pipe passes through the filter layer from bottom to top, backwashing the filter material. When the water level in the flushing water tank drops to the siphon destruction tube, air enters the siphon tube, destroying the siphon effect. The filter backwashing is completed and the next cycle of work begins.

Scope of Application
       Gravity valveless filter is widely used in surface water purification, groundwater iron and manganese removal, circulating water bypass filtration, production wastewater removal of suspended impurities, subsequent filtration of organic sewage after biochemical treatment and secondary sedimentation tank treatment, and filtration of indoor swimming pool water.
       At present, our factory produces two series of valveless filters: the square CBL-Ⅱ type filter tank and the round DLB-Ⅱ type filter tank. Both series operate automatically without valves for water inlet, outlet, backwashing and drainage, relying on hydraulic action. They feature low operating costs, easy management, safe and reliable operation, and compact integrated design combining inlet water tank, filter and backwashing water tank. Users only need to prepare the equipment foundation and connect the inlet and outlet pipes to put them into operation. All equipment is equipped with top covers, providing good sanitary protection conditions, and can be installed outdoors. Compared with reinforced concrete filters, they have lighter weight and use asphalt sand flexible foundations.

DLB-Ⅱ Type Filter Specifications, Models and Technical Parameters