Non return valve and water differential pressure switch

RFQ Details

Our company is looking for 25mm non return valves and water differential pressure switches suitable for installation into drinking water supply. With the non return valve is it possible to have a stronger spring fitted to allow the valve to hold against a 5 PSI head, 100 PSI (this pressure varies)on inlet and 95 on outlet valve remains closed, when outlet pressure drops below 95 PSI valve will open. The water differential pressure switches are required to operate at the similar pressures, the inlet side (high pressure) at 100 PSI the switch will be in the normally open position, when the outlet pressure dropes to 95 PSI the switch will close sending a signal to a solenoid valve to onen/ close.
Can you please send any information on these items.
Thanks
Sid