The Relief Cut
A Relief Cut, sometimes
termed and "Arcuate Cut"
was originally used to relief
pressure on a
turn-of-the-century gate
valve. The same principle
works well on a ball valve,
especially when particulates
are involved. The 24" copper
mining valve being loaded
above will benefit from this
feature as will other mining
and petrochemical
applications involving
slurries, catalysts, dry
abrasives and muds.
Copeland Industries
Severe Service Ball Valves
A relief cut is an option Copeland uses when
manufacturing valves involving slurries and larger valves
with high pressure drops. A small section is taken out of
the leading edge of both ports of the ball (press on
thumbnail to view details).
This option helps in two ways:
1. It relieves pressure faster when
the ball first starts to open. This helps
protect the sealing surface and
prevents "wire line draw" from
eating away at the ball and seat.
2. The sharp edge of the
valve has been removed and the
coating covers more of a flat surface.
This prevents the lip of the ball from
catching on a foreign object and
damaging the coating.
