Submittal Sheet

VBN THREADED CONTROL BALL VALVES AND ACTUATORS
15 63-4378—06
Cavitation Limits
To prevent cavitation (the formation and collapse of steam
bubbles), a conservative rule-of-thumb is to limit the
pressure drop across the control valve to:
ΔP < 1/2 x (absolute head pressure (psia) - water vapor
pressure (psia))
Water vapor pressure increases with fluid temperature,
reducing the allowable pressure drop, but even chilled
water can cavitate with sufficient pressure differential.
Typical pressure drop across a control valve is in the range
of 3 to 5 psid. Two-position valves will typically show 0.5
psid pressure drop. Design coil flow should be limited by a
balancing valve.
TYPICAL SPECIFICATIONS
Valve Actuator
Direct coupled actuator shall accept analog modulating
[(0)2-10 Vdc], floating (tri-state), or two-position signal as
indicated in the control sequence. Actuators shall be by
Honeywell. Actuator shall provide minimum torque
required for full valve shutoff position. Wiring terminals
shall be provided for installation to control signal and
power wiring.
Actuator shall be available with housing suitable for
outdoor installation.
Accessories Identification tags shall be available for all
valves; tags shall be indelibly marked with C
V
, model
number, and tag location.
Ball Valve
Valve housing shall consist of forged brass rated at no less
than 360 psi at 250°F. Standard valve ball shall consist of
chemically nickel-plated brass. Manufacturer shall be
able to provide optional 316 stainless steel ball and stem
for 2-way valves. Valve shall have a blow-out proof stem
with two EPDM O-rings with minimum 600 psi rating.
Valve stem assembly shall be of a pack-less design and be
field-replaceable without removing the valve body from
the piping. Manufacturer shall be able to provide glass-
filled polymer ball insert to make flow control equal
percentage. Valves shall be Honeywell. The 2-way valves
shall have EPDM O-rings behind ball seals to allow for a
minimum close-off pressure of 100 psi with actuator
which provides 35 lb-in. torque for 1/2 to 3 in. sizes. Valve
shall be available with a minimum of 53 unique C
V
values.
Valve shall be available with threaded (FNPT) end
connections. The 3-way valves shall be installed in a “T”
configuration with actuator perpendicular to shaft. Valve
shall not require elbows of any kind. The 3-way valves shall
have EPDM O-rings behind ball seals to allow for a
minimum close-off pressure of 40 psi with an actuator
that provides 35 lb-in. torque for 1/2 to 2-1/2 in. sizes.
The 3-way valves must be available in both mixing and
diverting configurations and shall be available with a
minimum of 42 unique C
V
values. Valve shall be available
with threaded (FNPT) end connections.