What is the primary function of the nozzle bellows in a fuel dispensing nozzle?

The primary function of the nozzle bellows in a fuel dispensing nozzle is to create a seal and enable vapor recovery. When fuel is dispensed, especially from underground tanks, vapors can escape due to the displacement of liquid. The nozzle bellows is designed to flex and create a tight seal, which prevents vapors from escaping into the atmosphere. This is essential not only for maintaining air quality and compliance with environmental regulations but also for ensuring that any vapors produced during the fueling process can be captured and returned to the storage tank, thus promoting safer dispensing operations.

The other functions mentioned in the other choices, such as regulating fuel flow or filtering impurities, are not the primary role of the bellows. While there are components in the nozzle that may help manage the flow of fuel or filter it, these tasks do not involve the bellows specifically. Similarly, while a disconnection from the vehicle can be part of the nozzle's overall functionality, it is not directly related to the purpose of the bellows in achieving vapor recovery.