In the industry, you use a throttling valve to regulate the flow of fluid. This type of valve may be a globe valve, needle valve, or some other type of that ilk. The valve may not be designed to ensure that, at full closed position, liquid cannot seep through the valve.
Adhering to the Unix philosophy, the isolation task is taken up by a block valve, which can be a gate valve, ball valve, butterfly valve (not so much).
Here’s an example in civilian life where a globe and ball valve are used in series to allow control of the water rate, yet guarantee a tight-shut off to conserve resources.
Wata - Malaysian Oil and Gas Engineer 