Which valve traps the fluid under pressure until pilot pressure overcomes the spring force and is sometimes called running away?

Which valve traps the fluid under pressure until pilot pressure overcomes the spring force and is sometimes called running away?

• A. Counterbalance valve
• B. Throttle type restrictor
• C. One-way control valve
• D. Flow control valve

Answer: (A)

The idea being tested is how to hold a hydraulic load in place and control when it can move. A counterbalance valve provides that hold by trapping the fluid on the actuator side under pressure. Its spring keeps the valve closed, so the fluid can’t pass until the pilot pressure acting on the valve overcomes that spring force. When the pilot pressure reaches that level, the valve opens and allows flow, enabling controlled movement of the load. This arrangement is used to prevent a load from “running away” when pump pressure drops or when a weight or gravity would otherwise cause uncontrolled descent. The valve maintains a minimum pressure to resist the load, offering safe, controlled operation of cylinders, hoists, or other vertical actuators. The other options don’t fit this purpose: a throttle-type restrictor, flow control, or a one-way (check) valve all control or permit flow in ways that don’t trap and release fluid based on pilot pressure to hold a load.

The idea being tested is how to hold a hydraulic load in place and control when it can move. A counterbalance valve provides that hold by trapping the fluid on the actuator side under pressure. Its spring keeps the valve closed, so the fluid can’t pass until the pilot pressure acting on the valve overcomes that spring force. When the pilot pressure reaches that level, the valve opens and allows flow, enabling controlled movement of the load.

This arrangement is used to prevent a load from “running away” when pump pressure drops or when a weight or gravity would otherwise cause uncontrolled descent. The valve maintains a minimum pressure to resist the load, offering safe, controlled operation of cylinders, hoists, or other vertical actuators.

The other options don’t fit this purpose: a throttle-type restrictor, flow control, or a one-way (check) valve all control or permit flow in ways that don’t trap and release fluid based on pilot pressure to hold a load.