Which device is critical for preventing the overfilling of LP Gas cylinders?

The overfilling prevention device is crucial for ensuring the safe handling of LP Gas cylinders. This device is specifically designed to prevent the overfilling of gas cylinders during the filling process. Overfilling can lead to hazardous situations such as gas leaks or cylinder rupture because excess liquid propane could expand and create pressure that exceeds the cylinder's safe capacity.

This device typically utilizes a float mechanism that automatically shuts off the flow of gas once the cylinder reaches a certain fill level. By stopping the refilling process at the appropriate time, this device significantly reduces the risk of overfilling and associated dangers.

In contrast, while a pressure regulator helps to manage the pressure within the system, it does not prevent overfilling. Similarly, a safety relief valve is designed to release excess pressure to prevent explosions but does not control the filling level. A flow meter measures the amount of gas flowing through the system but does not directly prevent overfilling either.