Final answer:
The correct option is 2. Dryers, after-coolers, separators, and receivers in pneumatic systems should be equipped with valves, which are crucial for controlling flow and pressure, alongside filters for removing contaminants and gauges for monitoring system status.
Step-by-step explanation:
In the context of pneumatic systems, dryers, after-coolers, separators, and receivers are typically equipped with devices to regulate pressure, remove contaminants, control the flow, and indicate system statuses. Therefore, the correct components that should be equipped in these systems are:
- Valves
- Filters
- Gauges
Valves are used to control the flow of air or fluid, shut off the system, or regulate the pressure within the system. Filters are important for removing particulate matter and water vapor to prevent contamination. Gauges help monitor the system pressure and temperature, providing valuable feedback for system operation.