Valve Structure Determines Installation Direction
Whether or not a globe valve is directional depends primarily on its internal structural design. There are two common types:
Straight-Through Type: The valve body is symmetrical, allowing the medium to flow freely in either direction from either end; therefore, no specific orientation is required during installation.
Angle Type: The inlet and outlet ports are positioned at a 90-degree angle relative to each other; consequently, the valve *must* be installed in accordance with the flow direction arrow marked on the valve body.
Interestingly, some globe valves feature a valve disc with a beveled (angled) design. These valves typically bear a flow direction arrow on the body; installing them in reverse may result in a reduction of approximately 20% in sealing efficiency.
Potential Consequences of Incorrect Installation
Even for globe valves that *can* technically be installed in either direction, there are practical considerations to observe during actual operation:
Operational Feel: When installed correctly, rotating the handwheel requires less effort; reverse installation may increase the required operating torque by up to 30%.
Ease of Maintenance: When the medium flows in the intended direction, the rate of wear on the valve stem packing is reduced by 50%.
Seal Lifespan: Forward-direction pressure helps to press the valve disc firmly against the sealing surface; reverse-direction flow may compromise the sealing effectiveness.
For a Reliable Installation, Follow These Tips:
Check the Markings: The arrow on the valve body *always* points toward the direction of the medium's outlet flow.
Inspect the Structure: The beveled surface of the valve disc typically faces the inlet side.
Test the Feel: When rotating the handwheel in the correct direction, the resistance should feel uniform and free of any binding or sticking.