HCV combined weight unloading valve I. Overview HCV combined weight unloading valve is composed of a two six-way valve, a two-way solenoid valve, a two-way manual valve and two-way throttle gathered together. Speed ??control system for the use of the hammer station shut-off valve in the hydraulic system. When an accident hydroelectric generating set low oil pressure, or governor closed water guide malfunctioning causing excessive speed hydro group ,, HCV when combined weight unloading valve action, its role in the differential pressure valve commutation, the governor removed, the servomotor, while the next two to take back the oil chamber, hammer hammer closed valve closed gate mechanism under gravity, to prevent accidents, the normal operation of hydro group provide safe and reliable protection. By optimizing the design of the product, a higher degree of integration, smaller, more reliable operation, long life, easy installation, layout small space; it's a one-way throttling device, adjustable relay's closing time, and can play a hydraulic buffer. Second, the characteristics of high degree of integration, small size, light weight, small footprint space, easy to install. Hydraulic buffer device, vibration-free sound, long service life. Throttle setting convenient, stable and reliable.