A flow control valve is a combination of which elements?

• A. Gate valve and relief valve
• B. Needle valve and a check valve
• C. Ball valve and throttle valve
• D. Stop valve and sequence valve

Answer: (B)

A flow control valve achieves adjustable speed by combining a throttling element with a one-way path. The needle valve provides fine, adjustable restriction, so you can set how much fluid passes in the controlled direction. The check valve offers a one-way flow, preventing backflow and allowing freer movement in the opposite direction. Together, they let you slow down movement in one direction while enabling quicker return in the other, which is the essence of flow control in many hydraulic and pneumatic circuits. Other pairings either don’t provide the needed throttling with a one-way flow, or are aimed at pressure relief or sequencing rather than direct flow rate control.