DYNAMIC
TESTING OF CHECK VALVES
SURGEBUSTER® and Air Cushioned Swing Check Valves
were flow tested under identical dynamic conditions and
the downstream pressure plotted as shown in Figures 1
and 2. The valves were installed on the discharge of a
four-inch 20 HP water pump and connected to a hydro-pneumatic
tank charged to 30 psig. After pump shutdown, the water
flow would rapidly reverse in about 1/2 second and cause
rapid valve closure.
The Air Cushioned Swing Check Valve was equipped with
a lever, weight, and air cushion with flow control valve.
Despite an operating velocity over 8 feet per second,
the Cushioned Swing Check Valve traveled only 15 degrees
or about 25% open. Partially open check valves are common
and can cause excessive headloss and energy consumption.
Adjustments to the air cushion revealed that any control
setting of the cushion, slowed down the valve closure,
and magnified the valve slam. In Figure 1, the valve closed
with a loud slam and produced an upsurge in the downstream
piping of 150 psi over the static pressure.
The SURGEBUSTER® was operated under the same flow
conditions and was found to open 35 degrees or 100% open.
In Figure 2, after pump shutdown the SURGEBUSTER®
closed with a negligible slam and produced an upsurge
in the downstream piping of only 25 psi over the static
pressure.
The dynamic tests demonstrate that the Surgebuster®
can reduce check valve slam up to 80% when compared to
conventional swing check valves. Numerous field installations
with vertical lines, multiple pumps, and high pump discharge
head all demonstrated the same result. The SURGEBUSTER®
provides non-slam operation with reduced headloss and
maintenance.
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