This valve, whose shield is attached to body to keep away the gate's corruption from outside condition, can be used in outside hard conditions thus increasing the life of the gate. The sealing principle is that when the gate is closed to the end, oblique plane of gate valve encounters wedge block of gate to close to achieve sealing effect, which makes the valve less blockage media. Its structure can be made into a hard seal, soft seal. Sealing requirements base on customer's selection. Soft-seal is a metal pressure sleeve to rubber ring sealed envelope locked in the valve seat tank, making ring will not fall off, and it's convenient  to take off metal pressure sleeve to replace the seat seal, besides ,not only  improve the valve's service life, but  also saves the user's  cost . The advantage of gate  valves are: open and close flexibly ,light in  structure, excellence in  sealing, and the soft seal rubber seal can be very easy to replace and so on, not only increases valve's life, but also saves a waste of resources.