@murchr the above pic is a sketch from the net. But it's a similar idea.
I got quotation from Doshi & Co (Hardware) Ltd. Nairobi. Prices for some items shocked me. Based on my quantities, total cost is coming to tune of sk200K+
None return valve 3" @7,850
Gate valve 3" @7,880
Gate valve 0.5" @510
T-joint 3" @750
T-joint 0.5" @30
Pipe 3" @1,630
Pipe 0.5" @220
Horse pipe 0.5" roll @1,690
Elbow joint 3" @550
Elbow joint 0.5" @30