Val-Matic Swing Check Valve - Manual (Page 4)

VAL-MATIC'S SWING CHECK VALVE
OPERATION, MAINTENANCE AND INSTALLATION
Page 4 of 13
disc has a chance to react to the diminishing
forward velocity of the water, the disc will be
driven to the closed position by the rapid flow
reversal. Depending on how fast the reversal of
flow takes place, a water hammer of different
magnitudes will develop.
The valve is available with an adjustable lever and
weight, an optional and adjustable lever and
spring assembly and a side mounted air cushion.
These assemblies and adjustments may be used
to vary the valve’s closing operation in order to
reduce the magnitude of the closing water
hammer.
The side mounted air cushion was designed to
solve minor water hammer problems. It should be
stated, that because the control media is only a
small volume of air at atmospheric pressure, that
is compressed to a maximum of 200 PSI and then
vented to the atmosphere thru a small flow control
valve, it should not be considered as a total
solution for severe water hammer problems.
INSTALLATION
The swing check valve with spring, weight and
lever, or weight, lever and
side mounted air
cushion can only be used for horizontal flow or
vertical flow-up applications. The valve must be in
a laminar flow region of the piping system. Avoid
locating the valve immediately downstream of a
pipe elbow or in a cavitation zone because the
turbulence in these regions will cause excessive
disc motion and will result in premature wear.
For horizontal flow applications the valve must be
installed with both of the pivot trunnions located
above the horizontal center-line of the valve and
the common center-line of the hinge trunnions
must be level to the horizontal plane of the valve.
For vertical flow up applications the counterweight
arm should be in the horizontal or about 30° below
horizontal position when the valve is
in the closed
position. The counterweight arm has multiple
keyways to allow for mounting in several
orientations.
Before installing the valve in the space provided,
check to make sure that the pump discharge
piping is free of foreign objects such as lumber,
tools, rocks, etc., which can damage the swing
check valve when it is placed in service.
When lifting the valve for installation, make sure
that lifting chains or straps are not attached to or
allowed to come in contact with the hinge pin,
counterweight arm or the side mounted air cushion
assembly. Also do not allow the weight of the
valve to rest on the hinge pin, counterweight arm
or the side mounted air cushion assembly.
Each valve is provided with a flow arrow integrally
cast on the valve cover. The flow arrow must
point in the direction the water will flow, when the
system is operating.
AWWA C508 swing check valves are furnished
with flat faced flanges and should only be mated to
a flat faced companion flange. A full faced or ring
gasket, that has been lubricated with a gasket joint
compound, must be installed between the valve's
flange and the companion flange to effect a seal.
Flange bolting shall be in accordance with ANSI
B16.1 Section 5.2 for cast iron bodies and ANSI
B16.42 for ductile iron bodies. Note: Val-Matic
does not recommend the use of high strength
flange bolting with these valves.
Before installing the flange bolting, the valve and
the adjacent piping must be supported and aligned
to prevent cantilevered stress being transferred to
the valve's flanges when installing the flange bolts
or studs.
Apply a thread lubricant to the flange bolt threads
and install the flange bolts and nuts around the
flange. Once all the flange bolts or studs are
inserted around the flange bolt circle, tighten them
hand tight.
Recommended flange bolt lubricated target torque
values for use with resilient gaskets (75
durometer) are given in Table 1. If leakage
occurs, allow gaskets to absorb system fluid and
check torque and leakage after 24 hours. Do not
exceed the bolt rating, the maximum torque of
Table 1, compress to more than the gasket
manufacturer’s thickness recommendation or
extrude gasket.