VM head design and Butterfly Valves

[OtisT]

VM head design and Butterfly Valves

I’m building a new VM head for my 3” column. My existing 3” head uses a 1” gate valve and I want something with the potential for faster takeoff. I am considering a 1.5” takeoff using a butterfly valve. I’ve never used a butterfly valve before and have some questions/concerns with this type of valve for this purpose.

Design Question: Will I have problem pulling foreshots with a butterfly valve? My concern is with the resolution at the low end, being able to find the right slightly open position for a slow takeoff.

None of the threads on butterfly valves I have read address this concern.

Otis