Geof
Mechanical
- Feb 2, 2001
- 59
I've attached a photo a Butterfly Valve being bolted to a Cast Iron Strainer - 8" Class 125 installation.
My concerns:
1. Turbulence - the butterfly valve is only rotated off by one bolt, so the load balance under flow as it feeds into the strainer won't be greatly affected. However, it is feeding directly into the inlet of a Y-strainer, basically a 45 degree elbow. What will this do to the strainer screen and butterfly disc loads?
2. Cracking Flange - flat face gaskets and A307 studs are recommended for cast iron flanges per ASME B16.1: With the ductile iron flange and ductile iron butterfly valve, plus the offset between bolts and point of contact with the butterfly valve face - how likely is this to damage the cast iron Y-strainer? I've seen butterfly valves bolted to cast iron flanges before, but I've also seen steel and cast iron flanges bolted together crack the cast iron flange.
Any comments are appreciated.
My concerns:
1. Turbulence - the butterfly valve is only rotated off by one bolt, so the load balance under flow as it feeds into the strainer won't be greatly affected. However, it is feeding directly into the inlet of a Y-strainer, basically a 45 degree elbow. What will this do to the strainer screen and butterfly disc loads?
2. Cracking Flange - flat face gaskets and A307 studs are recommended for cast iron flanges per ASME B16.1: With the ductile iron flange and ductile iron butterfly valve, plus the offset between bolts and point of contact with the butterfly valve face - how likely is this to damage the cast iron Y-strainer? I've seen butterfly valves bolted to cast iron flanges before, but I've also seen steel and cast iron flanges bolted together crack the cast iron flange.
Any comments are appreciated.