As the isolation device of the overall hydraulic test of the boiler unit in the power plant, the hydraulic test plug valve can be used as both the head of the boiler unit and the pipe. The application of the block valve saves the process of welding and cutting the blind plate, and the block valve can be repeatedly used, which improves the convenience and economy of operation and provides convenience for maintenance. However, there are many specifications and models of block valve, and the demand for the same specification is small. If the valve body adopts the mode of opening mold, the time-consuming and labor-consuming will also increase the cost of opening mold.
At present, forging is widely used in the market, so the cost of valve plugging is high. The following introduces a kind of machining method to process the blank of cast steelbody to block the valve body, which avoids the above problems.
The structure of common cast steel medium and low pressure cylinder gate valve and high pressure self tightening seal gate valve is shown in Figure 1.
By changing the parts of the flow passage of the valve body, the block valve can play two different working states, i.e. hydrostatic test state and normal working state. Its structural type is shown in Figure 2.