Manufacturing method of wedge gate valve with internal relief valve
Gate valve is generally composed of valve body, valve seat, gate plate, valve stem, valve cover, bracket, transmission mechanism, seal and mounting parts, which belongs to multi rotation open close valve. In the process of valve opening, due to the large pressure difference between the inlet and outlet sides of the gate, the valve opening torque is large, the wear between the sealing faces is also large, and the sealing performance decreases rapidly. Therefore, in order to reduce the opening torque of the valve, the bypass valve is generally installed between the inlet and outlet of the valve. Before the main valve is opened, the bypass valve is opened to reduce the pressure difference on both sides of the gate, reduce the wear between the opening torque and the sealing surface, and improve the sealing performance. However, the bypass valve device makes the structure of the valve complex, the cost is increased and the opening and closing operation is troublesome.
The purpose of the utility model is to provide a wedge gate valve with internal pressure relief valve, which has the advantages of small opening torque, less wear between sealing surfaces and no increase of product cost, simple structure and convenient operation.
The technical scheme for realizing the purpose of the utility model includes a valve body, a valve seat, a gate plate, a valve stem, a valve cover, a bracket, a transmission mechanism, a sealing part and a mounting part. It is mainly to manufacture mutually matched sealing surfaces on the lower end of the valve rod and the gate to form a pressure relief valve device. The outlet of the pressure relief valve is connected with the valve outlet channel by the pressure relief hole, and the inlet of the pressure relief valve is connected with the valve inlet by the pressure hole The channel is connected.
In the above scheme, the lower end of the valve rod is made into a positive conical sealing surface, and the circular hole sealing surface on the gate plate constitutes a stop valve type sealing structure.
Compared with the prior art, the utility model has the beneficial effect of forming a pressure relief valve between the lower end of the valve stem and the ram. When the valve is opened, the valve rod is lifted to open the pressure relief valve, so that the medium pressure at the inlet side passes through the pressure relief hole and the pressure relief hole to the outlet side, so as to reduce the pressure difference between the inlet and outlet sides of the ram, and then lift the ram to reduce the opening torque of the ram and reduce the wear of the sealing surface, It has the advantages of simple structure, convenient operation and low cost.