Stop Valve

A stop valve is any sort of valve system that totally stops the flow of liquid through a pipe. There are many styles of stop valves, but two of the most common are gate valves and globe valves. Gate valves dont restrict flow when not in use, but they take longer to move into position and are more likely to leak. A globe valve will interrupt flow at all times, but will move into position very quickly. Both of these valve types are common on piping systems of all shapes and sizes.
Most of the time, a stop valve is necessary as a safety feature. These valves completely stop flow of any kind through the system, often to avert a crisis before it can get out of hand. As a result, these valves are generally close to important machinery or a human workstation. A stop valve may have a manual crank or may be incorporated into an automated system. Manual stop valves typically have a brightly coloured screw handle, the kind common in many pipe systems.

From the original1Gate Valve.com
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