What component in a vapor recovery system helps control vapor flow?

• A. Regulator
• B. Pump
• C. Filter
• D. Vent valve

Answer: (D)

In a vapor recovery system, the vent valve plays a crucial role in controlling vapor flow. This component is designed to open and close based on vapor pressure changes within the system, thereby regulating the amount of vapor that is either released or contained. When the pressure in the tank rises due to the addition of liquid or due to temperature changes, the vent valve can open to allow excess vapor to escape, thereby preventing overpressure conditions. Conversely, when the system is under low pressure, the valve can remain closed to maintain the necessary positive pressure for effective vapor recovery.

Understanding how the vent valve operates is essential for maintaining safe and efficient vapor recovery operations, as it directly affects the system's ability to prevent vapor loss to the environment and ensure compliance with regulations aimed at reducing air pollution.