I don't know if it is still made, however if it is it could be a solution for you. George Fischer (+GF+) used to make a thermoplastic heat exchanger.
It was not good for any applications which required a great deal of heat, nevertheless, if the volume of water is not too great, and the delta...
It is really late, but may be worth pointing out the difference between loss of power, loss of air and loss of signal - all of which could be handled differently.
Positioned valves could be designed to "fail" in a number of different positions depending on the failure mechanism.
The valve...
The typical min/max velocity through a check varies on the type of check. Ultimately you want the check to get to a fully open position as soon as possible and to close before flow reversal.
I like to take the position that a check valve is like a flow activated control valve. A perfect check...
The exotic alloy & super duplex options are great - provided there is budget for it. Also, I'd reccomend a valve that removes as much of the corrosive condition away from the internals or moving parts. If you can elliminate the contact surfaces to the disc and seat you are ahead of the game -...
There are a couple of good options depending on pressure requirements. There now thermoplastic valves available up to 48" in diameter - however they don't have the mechanical strength or pressure ratings of a metal valve. The Nylon coated disk options work well so long as you can avoid pinning...
