How do choke valves work?
Choke valves works basically as a faucet (a faucet is actually one kind of a choke valve). It ‘chokes’ or controls the flow of liquid (or even gas) passing through it. Think of two concentric cylinders. Both the inside and outside cylinder will have many holes. As you ‘open’ the choke, more n more of these holes will align and the flow from the cylinders will increase as the opening has increased.