Selector valves play an important role in many modern airplanes. They are commonly found in commercial airliners and other large fixed-wing aircraft. Pilots can control them from inside the cockpit. To learn more about selector valves and how they work, keep reading.
Overview of Selector Valves
Selector valves are mechanical devices that control the flow of fluid. They don’t just allow or block the flow of fluid. Rather, selector valves guide fluid, allowing pilots to control where the fluid goes.
Fuel vs Hydraulic Fluid Selector Valves
Two of the most common types of selector valves in airplanes are fuel and hydraulic fluid. Fuel selector valves are designed to control the flow of fluid. Hydraulic fluid selector valves are designed to control the flow of hydraulic fluid.
Fuel selector valves allow pilots to switch between different fuel tanks. Instead of a single fuel tank, many airplanes have multiple fuel tanks. Using a fuel selector valve, pilots can draw from a specific fuel tank. If there’s a single fuel tank in each wing, for example, the pilot may want to regularly switch between the two tanks to maintain proper balance.
Fuel selector valves often have OFF, LEFT and RIGHT positions. The OFF position stops the flow of fluid and is typically used for maintenance purposes. The LEFT position draws fuel from the left fuel tank. The RIGHT position draws fuel from the right fuel tank.
Hydraulic fluid selector valves allow pilots to send hydraulic pressure to a particular system. Hydraulic systems use fluid to create pressure and, thus, move various components. Landing gear, flaps and spoilers are often powered by hydraulic systems. When the pilot lowers the landing gear, a hydraulic fluid selector will send pressure to the landing gear.
How Selector Valves Work
Selector valves work by changing the direction in which fluid travels through a given system. They typically consist of several parts, including a main valve body and a moveable rotor or spool.
The rotor or spool is designed to align with different passages. When the pilot activates a selector valve, for instance, the rotor or spool will move so that it aligns with a particular passage. Fluid will stop flowing to the old passage and, instead, begin flowing to the newly aligned passage. Activating the valve body will change the direction of the fluid.
Of course, selector valves aren’t limited to the aviation industry. They are used in many other industries, such as construction equipment, agricultural machinery, marine vessels and more. Regardless, they are all designed to control the flow of fluid.