Val-Matic Swing Check Valve - Manual (Page 5)

VAL-MATIC'S SWING CHECK VALVE
OPERATION, MAINTENANCE AND INSTALLATION
Page 5 of 13
The target torque for flange bolting is based on the
flange construction, system pressure, system
temperature, and the gasket material. The valve
flange construction is per ASME B16.1 Class 125
(cast iron bodies) or ASME B16.42 Class 150
(ductile iron bodies). The gasket material and
design is often the limiting factor for the flange bolt
target torque and should best be obtained from the
gasket manufacturer. Note: Flange joint leakage
can be caused by exceeding the recommended
target torque as well as inadequate or non-uniform
bolt torque.
The flange bolt torque should be applied in several
graduated steps using the cross-over bolt
tightening method to load the bolts evenly to
eliminate concentrated stresses which could
fracture or crack the valve's flange. See ASME
PCC-1-2010 for details of the cross-over bolt
tightening sequence and torque methods. Note
that the target torque values provided in ASME
PCC-1-2010 are based on the ANSI/ASME steel
flange pressure and temperature ratings which
exceed those of AWWA and are, therefore, often
higher than appropriate for AWWA rated iron
valves and flanges.
VALVE START-UP PROCEDURE
When the swing check valve with weight arm,
spring, and/or side mounted air cushion is
completely installed, follow the steps outlined
below to place valve into service. A combination
of the weight, spring and side mounted
adjustments may be necessary depending on the
valve’s optional equipment configuration and the
installed system performance.
Become familiar with the following adjustments
that will affect the closing characteristics of the
swing check valve's disc.
There is a “Start-Up Observation Record” form at
the end of this manual that may be useful during
start-up operations and recording the “Final, As
Left” set-up configuration.
LEVER AND WEIGHT ADJUSTMENTS
Moving the weight in towards the hinge pin center-
line will increase the disc's closing time and
moving the weight out away from the pivot shaft
center-line will decrease the disc's closing time.
Note that the position of the weights can also
affect how far the valve's disc opens under low or
moderate flow conditions.
LEVER AND SPRING ADJUSTMENTS
Moving the spring connection in towards the hinge
pin center-line will increase the disc's closing time
and moving the spring connection out away from
the pivot shaft center-line will decrease the disc's
closing time. Note that the position of the spring
connection can also affect how far the valve's disc
opens under low or moderate flow conditions.
Increasing the spring tension will decrease the
disc's closing time and decreasing the spring
tension will increase the disc's closing time.
AIR CUSHION FLOW CONTROL VALVE
ADJUSTMENTS
There are two speed control valves externally
mounted on the air cushion cylinder ports. To
increase the cushioning effect (increase closure
time) the upper (cylinder rod end) speed control
should be full open and the lower (cylinder cap
end) speed control is used to control the
cushioning effect. Turning the lower external
speed control valve's adjustment knob of the side
mounted air cushion clockwise will increase the
cushioning effect and increase the valve's closing
time and turning the lower external speed control
valve's adjustment knob counter-clockwise will
decrease the cushioning effect and decrease the
valve's disc closing time. If the lower speed
control valve is fully opened and a reduction in the
closure time is desired, the upper (cylinder rod
end) speed control valve should be fully closed
while the swing check valve is in the full closed
position. This will add a pressure boost to the
initial portion of the closing stroke.
TABLE 2.
FLANGE BOLT TARGET TORQUE
Valve Bolt Recommended Maximum
Size Dia. Torque Torque
(in) (in) (ft-lbs) (ft-lbs)
2” to 4”
5/8 25 90
6”-8” 3/4 30 150
10”-12” 7/8 45 205
14”-16” 1 80 300
18”-20” 1 1/8 100 425
24”-30” 1 1/4 150 600
36”-42” 1 1/2 300 900
48” 1 1/2 300 1,000
CAUTION
The use of ring gaskets or excessive bolt
torque may damage valve flanges.