To synchronize the extension speed of two hydraulic cylinders operating under different loads, the key objective is to balance the fluid flow to each cylinder. This ensures that despite varying loads, both cylinders extend at the desired speed. The most effective method to achieve this balance is:

1. Installing Flow Control Valves: Placing flow control valves in the supply lines to both cylinders allows for precise adjustment and control of the fluid flow rate. By independently controlling the flow to each cylinder, you can ensure that each cylinder receives the appropriate amount of hydraulic fluid needed to extend at the required speed, despite differences in load.

Let’s evaluate why this option is the best, and why other options are less suitable:

• Placing a Flow Control Valve Only in the Return Line from Both Cylinders: This controls the fluid flow out of the cylinders, but does not address imbalances in the input flow, which directly affects synchronization.
• Adjusting Pump Output to Increase Overall System Pressure: While increasing system pressure might provide more power, it doesn’t specifically address the need to synchronize cylinder speeds, as it uniformly affects both cylinders.
• Using a Pressure Relief Valve to Stabilize System Pressure: Pressure relief valves prevent excess pressure but do not help in synchronizing cylinder speeds, as they are not designed for controlling flow to individual cylinders.

Thus, the correct application is installing flow control valves in the lines to both cylinders to effectively balance the fluid flow. This method provides the necessary control to ensure both cylinders operate in unison despite differences in load.