Problem of valve plate detachment in the outlet electric gate valve
Thread Content
A center-split centrifugal pump with a flow rate of 360 and a head of 90 meters; the fluid handled is clean water. Under normal conditions, the current consumption is 300 A, but after it stops operating once and then starts up again, the current drops to 180 A. The water pump was checked and is fine; the inlet valve, which is a butterfly valve, is also in good condition. The valve plates of the check valves have been removed – it seems that the outlet valve’s plate has fallen out, preventing water from flowing out. When the electric outlet valve is opened manually, the pump will reverse direction. Moreover, when opening this outlet gate valve, water leaks from the packing area, which indicates that the valve disc can be opened to some extent. Then why does the valve disc still fall apart despite being able to open a little? If the valve disc hasn’t fallen out, why can’t water be pumped out? . .
This is a typical phenomenon when the valve stem of a gate valve is severely corroded. This is because in new gate valves (typically those with two gate plates), the end of the valve stem has a larger diameter, and the thickness of this portion limits the minimum width of the two gate plates. When corrosion occurs and this diameter becomes smaller, leakage at the packing area becomes severe. However, when the valve is fully opened, leakage is generally less due to the sealing surface on the other end of the gate plates. In other words, if the valve is not opened or only partially opened, it will leak, and the leakage may be severe
What’s going on with the electric valve for water discharge and the pump running in reverse?
Because it is connected in parallel with another pump, the outlet electric valve reverses direction as soon as it is opened a little; the check valve is damaged, and its valve plate was removed by us after it fell off.
The question is why it can only be turned up a little. . The situation is that the gate valve’s plate seems to have fallen out; that’s why it can be opened only a little bit and not fully. This leakage indicates that the gate valve is slightly open, but there is no flow at all when the pump is started.
A leak does not indicate that the valve is open; the gate valve needs to rotate a significant distance for the gate to reach the open position. The reason it may not open is severe corrosion of the valve stem – removing it and welding it back together will allow it to be used again with no problems.