The flap of the swing check valve and the rocker are connected together and can rotate a certain angle around the pin axis. When the pipeline fluid flows in from the specified direction (from left to right), the inlet pressure of the valve flap is higher than the outlet pressure. At this time, the valve is pushed away from the valve seat, rotated a certain position about the pin axis, and the valve is in the open state. When the pressure difference between the two sides of the valve disc is reduced to a certain value, the valve disc falls and returns to the closed state. When the fluid flows from right to left, that is, reverse flow, the pressure on the right side of the valve disc is higher than the pressure on the left side, and the pressure generated by the pressure difference on both sides presses the valve against the valve seat. If the fluid cannot pass, the medium cannot go backward.
And the greater the fluid pressure, the tighter the sealing surface pressure, the better the sealing effect.
The installation position of the flow-swing check valve is not limited. It can be installed horizontally in the pipeline, or it can be installed on vertical or inclined pipelines.
There are two types of straight-through lifting check valves, one with spring and one without spring. The one with spring can be installed vertically and horizontally. The one without spring can only be installed vertically. The vertical lift check valve is a swing check valve.
The straight-through lifting check valve generally does not have a spring, only small diameter, DN <50, the valve itself is closed by the weight of the valve disc. Vertical lift check valve and swing check valve are two types of valves, with different working principles and different shapes.
The vertical lift check valve looks like a barrel, but it is fat in the middle. The straight-through lift check valve has a similar shape to a stop valve and has a bonnet.