Issue of the rotation direction of the valve stem
Thread Content
I recently encountered a problem; I’ve faced it before as well, but didn’t pay it much attention. It concerns determining the installation direction of the valve stem – should it be in the same direction as the flow of the fluid or opposite to it? Sometimes, due to limited space, only enough room is available on one side of the valve for the valve stem to rotate; therefore, it is necessary to know exactly in which direction the valve stem will rotate in order to facilitate installation. If the valve is operated by a handwheel, there is no such problem
Is the poster referring to a ball valve? In the past, the shafts of ball valves were square-shaped rods, so the valve stem could be installed in any direction. Nowadays, many companies have switched to rectangular rods, meaning that the valve stem can only be installed in one direction.
The installation of ball valves is directional; there is a seal ring on the ball valve, and this seal ring should be located on the downstream side of the fluid. This is to ensure that if a leak occurs in the seal ring, the ball valve can be closed to prevent leakage.
When the ball valve is equipped with a handle, the open or closed state of the ball valve is determined by the direction of the handle: when the handle is perpendicular to the direction of fluid flow, the ball valve is in the closed state; when the handle is in the same direction as the fluid flow, the ball valve is in the open state. But there are also the opposite ones on the market. Caution is still required when using it.