Typically, the two most common control valve types you see in food and beverage industry applications are a plastic or metal check valves, or ball valves. Both check and ball valves work to prevent backflow from occurring. With check valves, they rely on pressure in the line to activate valve open or close functions. A check valve will open or crack as line pressure increases. It will close and seal when the pressure drops preventing backwards media flow. The ball valve is manually opened or closed to control flow. Specialty manufacturing makes Ball and Check valves with a vast array of materials, end, spring and size options.