"Filtration" is an indispensable technology in water treatment. ZW-F type steel valve without valve to create a new trend of domestic filtration technology. From the water, filtration, water, back flushing and sewage and other all by hydraulic role, to achieve full automatic work, without the need for special operations management. Thus, it will completely replace the production of China for several decades, and is suitable for all types of water treatment filter equipment, with a high water saving, power saving, section labor, small footprint, sewage and so on.