What is a common application for flow control valves in pneumatic systems?

Flow control valves play a critical role in managing the speed of actuators in pneumatic systems. By regulating the flow rate of compressed air entering an actuator, these valves directly impact how quickly or slowly the actuator can extend or retract. This capability is essential in applications where precise control of movement is necessary, such as in automation processes or robotic arms, where different speeds may be required for specific tasks.

For instance, if an actuator needs to move slowly to avoid damaging delicate components or to ensure accuracy in positioning, a flow control valve can be adjusted to limit the airflow, thereby reducing the speed of the actuator's movement. Conversely, it can be set to allow rapid movement when speed is not a critical factor. This illustrates the importance of flow control in ensuring functionality and safety in pneumatic systems.

In contrast, the other options relate to functions that do not align with the primary purpose of flow control valves. Building pressure usually involves pressure regulators or compressors, unrestricted flow pertains to direct supply lines without control mechanisms, and changing cylinder type is a matter of selecting specific components rather than controlling flow within a system.