Which valve is also known as 'running away' and traps fluid under pressure until conditions change?

• A. Counterbalance valve
• B. Flow control valve
• C. Meter-in
• D. One-way control valve

Answer: (A)

Holding a load against unintended movement requires a valve that traps fluid on the cylinder side to maintain pressure until the load changes. This is the job of a counterbalance valve. It is placed in the circuit to keep the actuator side pressurized, opposing gravity or an external load when the pump is off or when demand drops. The valve sets a threshold pressure and will only allow fluid to bypass back to the reservoir when the load pressure exceeds that setting, effectively holding the load in place and preventing a sudden rush or “runaway.” That holding capability is what makes it the correct choice for stopping runaway motion.

Flow control valves and meter-in devices primarily regulate how fast fluid moves, not whether the actuator stays put against a load, so they don’t provide the necessary load-holding function. A one-way (check) valve blocks flow in one direction but does not maintain a controlled, pressurized hold on the actuator side.