Backflow prevention drain valve

[WHPES]

I'm looking for something to prevent back flow into a surface water drain when the beck floods. I rember some cast iron thingy from years ago which went in line and had a small chamber with a ball which floated up and closed off an orifice from the land drain which the sewer level rose. None of my builders merchants have seen anything like that or can suggest anything. Anyone ever seen one for sale or got any suggestions?

 

[WHPES]

Been told what I am referring to is a Couzens ball trap interceptor or Dyers backflow prevention valve and they haven't been made since the 60s so need some ideas folks!

 

[ecowarm]

Marley REDI Non return, backflow prevention/check valve DN100 - Combined Harvesters This is a Marley product so the merchants should be able to supply it

 

[WHPES]

Thanks that looks the ticket!

 

[johnconner1515]

In my underground sprinkler system i have the copper pipe coming out of my house. At that point.

 

[scottyblen]

instead of me making new threads all the time i thought i would post here.

what are the 2 major ways in which water in a system may become contaminated??