The through conduit gate valve is a typical parallel gate valve.The through conduit expanding gate valve is developed on the basis of slab gate valve. Instead of one “slab”, the disc consists of two halves with a wedge-shaped interface. Both the female and male gates are provided with complementary opposed inner faces, each formed with two angular-related surface portions diverging transversely. The two halves(gates) are interlinked so that they wedge apart when being moved into the fully open or closed positions, but relax in the intermediate position during the disc travelling stroke. The wedge mechanism ensures tight seal on both upstream and downstream seating surfaces even at low pressure levels. Through conduit gate valves are widely used in oil & gas, petrochemical, power plant and mining industries.