for transferring sanitizer and other non-beer fluids from one corny keg to another, I thought of a way to use bike pump pressure.
Using 3/16" ID gas tubing and a gas QD, I connected a Presta valve from an innertube. It fits right into the tubing, and I held it with a hose clamp. I tested it over 40psi and it works beautifully. I can use it to deliver pressuriized water or sanitizer anywhere I need it.
Be careful if you build one with a new bike pump. There is usually lots of oil all over the piston in those pumps and when brand new it will spit oil out with the air. You don't want that oil in the keg. After the pump has been used a lot I don't see much oil, maybe just disassemble and clean off the oil in a new pump and replace with keg lube?