What do you think are the relative merits between butterfly and ball valves?
I figure the butterfly valve is easier to clean, but the ball is less likely to get clogged. Anything I'm missing?
How about this for a clog?
That is a 24" butterfly valve that was located just downstream of a sodium hydroxide injection point in a water system. The NaOH was added to control corrosion potential in the distribution system. Unfortunately, the caustic did not mix well in the pipe and it precipitated the deposits in the pipe and on this valve. I would expect that the deposits were calcium carbonate (chalk), but the high OH concentrations actually caused calcium hydroxide (lime) to deposit instead.
This isn't really applicable to this discussion, but I figured some might enjoy the mysteries of water chemistry (when done wrong).