What component is used to realize an OR logic function with two pressure sources?

What component is used to realize an OR logic function with two pressure sources?

• A. A check valve
• B. A relief valve
• C. A shuttle valve
• D. A pressure regulator

Answer: (C)

To realize an OR function with two pressure sources, use a shuttle valve. It has two inlets and one outlet, and an internal shuttle (a small ball or disc) moves toward the side with higher pressure. This seals off the other inlet and passes the active source to the output, so the actuator is pressurized as long as either source is active. If both sources are present, the one with higher pressure dominates; if only one is present, that one drives the output. This setup directly implements the OR behavior: the output is energized as long as at least one input is pressurized. A check valve wouldn’t combine two inputs; it only allows flow in one direction from a single source and blocks the other. A relief valve is for releasing excess pressure, not combining inputs. A pressure regulator sets a controlled downstream pressure, not an OR gate.

To realize an OR function with two pressure sources, use a shuttle valve. It has two inlets and one outlet, and an internal shuttle (a small ball or disc) moves toward the side with higher pressure. This seals off the other inlet and passes the active source to the output, so the actuator is pressurized as long as either source is active. If both sources are present, the one with higher pressure dominates; if only one is present, that one drives the output. This setup directly implements the OR behavior: the output is energized as long as at least one input is pressurized.

A check valve wouldn’t combine two inputs; it only allows flow in one direction from a single source and blocks the other. A relief valve is for releasing excess pressure, not combining inputs. A pressure regulator sets a controlled downstream pressure, not an OR gate.