Val-Matic Threaded Silent Check Valve - Manual (Page 2)

1
THREADED STYLE SILENT CHECK VALVE
OPERATION, MAINTENANCE AND INSTALLATION
INTRODUCTION
This manual will provide you with the information to
properly install and maintain the valve to ensure a
long service life. The Threaded Silent Check Valve
is ruggedly constructed of lead-free bronze to give
years of trouble free operation. The valve should be
installed in horizontal or vertical pipes carrying clean
water.
The Threaded Silent Check Valve is designed to
open fully to provide flow in the forward direction and
close rapidly upon flow reversal. The valves are
used to prevent reverse flow through pumps or in
piping systems. The size and cold working pressure
(250 CWP) are marked on the body for reference.
This valve is not intended for fluids containing
suspended solids such as wastewater.
RECEIVING AND STORAGE
Inspect valves upon receipt for damage in shipment.
The valves should remain boxed, clean and dry until
installed to prevent weather related damage. For
long term storage, no special provisions are needed.
DESCRIPTION OF OPERATION
The Threaded Silent Check Valve is designed to
prevent reverse flow automatically. On pump start-
up, the flow of water enters the valve from the seat
end (right side in Figure 1) and forces the disc open,
allowing the passage of fluid through the valve.
On pump shut-down, the spring closes the disc
rapidly before a flow reversal takes place. This type
of closure, which prevents flow reversal, is the factor
which provides “silent” operation and reduces water
hammer associated with check valve slam.
The valve body is supplied with NPT tapered
threads on each end for installation in pipelines.
FIGURE 1. THREADED SILENT CHECK VALVE
INSTALLATION
The installation of the valve is important for its
proper operation. The flow arrow on the valve body
must point in the direction of flow when the system is
in operation. The valve can be installed in horizontal
or vertical lines with the flow up or down.
Three diameters of straight pipe upstream of the
valve are recommended to prevent turbulent flow
streams through the valve, which can cause
vibration and wear.
When installed in horizontal lines, the check valve
does not have a specific upward orientation. Insert
pipe nipples with thread sealant or thread tape and
tighten while securing valve with a wrench on the
body end nearest the pipe nipple.
CAUTION
The use of excessive torque can damage the
valve.
CAUTION
This valve is not intended for fluids
containing suspended solids or hazardous
fluids.