Okay kiddo, imagine you have a faucet in your kitchen that controls the flow of water, right? And you can turn it to make the water come out slower or faster? Well, imagine that same concept but for much bigger machines that make things like electricity or chemicals or oil.
A control valve is like a grown-up version of that kitchen faucet, but instead of water, it controls the flow of things like steam, gas, or liquid. These valves are usually made out of metal and have a knob or lever that you can turn to adjust how much of the substance is flowing. Some control valves have special sensors or electronics that help to automatically adjust the flow depending on what's going on in the machine.
Without control valves, it would be very difficult to keep machines working the way they're supposed to. If too much steam or gas or liquid is flowing, it could cause damage or even shut down the machine altogether. But with control valves, we can make sure that just the right amount is flowing, which keeps everything running smoothly and efficiently.