Plumbing and Piping - Sump Pump Discharge (Check Valve)

Is there a device I can install in 2 in plastic drain pipe to eliminate the slam when the pump shuts off? I thought I saw something that resembles a backflow preventer with a cylinder on top of it that will absorb the water shock and eliminate the slam noise. The thing I saw was on pressurized water pipes, but I thought it might be available for this application too. I have about 50 yards of sump line to pump latterally, and about 8 feet up to get from the sump to the crawl space where the latteral line is. Any suggestions?

I just read about a silent check valve that's supposed to work. Do a google for:

"A.Y. McDonald - silent check valve"

If you try it, please post back. I've gotten one good report so far.

Silent check valves work great-buy one!!

I ordered one from a local distributor of A.Y. McDonald Co. and am looking forward to installing it. This pipe slam has been a BIG pain for a long time, but at least I knew that the pump was running! Now I will have to depend on the sump alarm company...no problem there! It said something in the literature that this has a special hinge in the flapper valve that deadens the sound somehow when it closes from the back pressure. Does anyone know how?

Thanks!

We have 2 different types of silent check valves. One style has a regular flapper and then above is another rubber flap that has a slit in it. I suppose that upper flap slows the returning water down so it doesn't pound on the lower flap. The other style has a spring pushing the flap closed. I'm not sure how that one is suppose to work but it seems to.

The "Silent" Check valve made a BIG difference. I can still hear it, but it doesnt shake the floor like it did before. Thanks guys!

Thanks for posting back. I don't need one very often, but when I do I'll know where to go.