July 15, 2020
Does Orientation Matter?
When it comes to a preferred orientation of installing resilient-seated butterfly valves, there are various schools of thought. One widely-held opinion is that installing the valve with the stem horizontal (valve on its side) in horizontal piping is preferred, in order to allow any debris or solids in the line to pass over the liner and not accumulate in the stem areas. Conversely, in the Milwaukee Valve lug butterfly IOM, it is recommended that the stem be installed vertically (valve upright). This minimizes side-loading of the nylon bearings and liners due to the weight of the disc, particularly in larger sizes.

But, there are exceptions. When the valve is under pressure, the valve doesn’t care how the stem is oriented. The pressure is equal around the entire inner circumference of the valve.

Either orientation has merit and is valid. Therefore, whether the installer wants to mount the butterfly valve right-side up, upside down, or somewhere in between, Milwaukee Valve will support whatever installation position is required for ease of operation.
For questions or additional clarification, contact your Milwaukee Valve sales representative or your regional manager. 
16550 West Stratton Drive, New Berlin, WI 53151