Double-plate gate valve and use of the same

A double-plate gate valve, comprising a valve body, a valve cover, a valve stem, a guide plate, a goggle-like plate assembly, an adjustable pipe assembly, a disc spring assembly and a valve plate and wedge assembly, wherein

• the guide plate is nested in a valve chamber formed by the valve body and the valve cover;
• the goggle-like plate assembly is configured to provide mounting support for the adjustable pipe assembly and the valve plate and wedge assembly in the valve chamber, the goggle-like plate assembly is allowed to move along with the adjustable pipe assembly and the valve plate and wedge assembly in the valve chamber, and floating seals are formed at a contact surface between the adjustable pipe assembly and the guide plate, and at a contact surface between the valve plate and wedge assembly and the guide plate;
• the adjustable pipe assembly is adjustable, that is, a face-to-face distance and a sealing force between a sealing surface of the adjustable pipe assembly and a sealing surface of the valve body are adjustable, to allow a straight through pipe to be formed and an elastic seal between the adjustable pipe assembly and a valve seat to be formed in a case that the valve is fully opened;
• the disc spring assembly is configured to overcome friction forces of the valve plate and wedge assembly and the adjustable pipe assembly during a closing process of the valve;
• and
• the valve stem is configured to transmit actuating forces during opening and closing processes of the valves;
• and wherein
• the adjustable pipe assembly comprises an adjustable pipe structure, wherein the adjustable pipe structure comprises an upper flange, a lower flange and a circular guide tube, the upper flange is fixedly connected with the circular guide tube, and a plurality of slots are uniformly provided at a side edge of the upper flange;
• the adjustable pipe assembly further comprises an adjusting bolt, a disc spring A, a disc spring gasket, a force-adjustment nut, a locking nut and a distance-adjustment nut which correspond to each of the plurality of slots;
• wherein the adjusting bolt is mounted in the corresponding slot, and the disc spring A, the disc spring gasket, the force-adjustment nut, the locking nut and the distance-adjustment nut are sequentially mounted on the adjusting bolt;
• the disc spring A is in contact with a lower surface of the corresponding slot, and is pressed against the lower surface of the corresponding slot by the disc spring gasket and the force-adjustment nut;
• and
• the adjustable pipe assembly further comprises packing A and a lower-flange packing gland;
• the packing A is filled between the lower flange and the circular guide tube, and the packing A is pressed by the lower-flange packing gland, to ensure a seal between the lower flange and the circular guide tube;
• the distance-adjustment nut is in contact with the lower-flange packing gland;
• and the lower flange is fixedly connected with the lower-flange packing gland.