I have an 8" check valve that I need to replace that is in the vertical plane 11" from the discharge of a 1435 gpm pump.  We have replaced one in the past with another swing type check valve and it now makes the awfullest beating and banging noise when the pump is running.  Since the swing check valve relies on gravity (weight of disk) to shut off, I believe that sudden surges in flow is causing the disk to relax and slam back against the inside of the valve since 1435 gpm of water discharged from a pump is pretty turbulent.  I don't believe we have a water hammer problem, but I could be wrong.  What I'm looking at replacing the current valve with is an APCO Series 600 Globe Style Silent Check Valve.  To fit in place of our existing valve we would have to add a 9 3/8" spool piece giving a possible distance of 20 3/8" from the pump discharge to the check valve.

Now my questions: Does anyone think that the silent check valve is not a good idea in my situation?  Can someone give me any pros and cons by going with a silent check valve?  I have my own, but I'd like to see what others have to say.  Any other advice is also welcomed.

P.S.> I have to be able to get this valve no later than 3.5 weeks from now.

Crane's Technical Paper No. 410 has information on check valves. They need to be sized for the flow conditions. Check valves are a lot like control valves - they're usually one pipe size smaller than the correctly sized line in which they're installed.

Over-sized check valves never fully open, and the discs flap like flags in the wind. This is the prime cause of these valves wearing out before their time. A check that's over-sized, never fully opening, will typically have a larger pressure drop than a smaller, properly sized valve that opens right up.

Your swing check is too probably too large for the flow/pipe size.
Your line velocity is around 1.9 m/s. You want at least 2.4m/s to open the disc fully for a conventional design swing check.I assume you are pumping water If you have an external spindle, installing an arm and a spring (acting in the closed direction) will help at the expense of wasting power.
Wafer type check valves work OK and are cheap and easy to fit, but the springs eventually break and water hammer ratings are not that brilliant.

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