An externally mounted mechanical device for mechanically closing a pressurized tank or cylinder valve, such as a grill tank, is provided. The device comprises a securing mechanism, a rotatable mechanism having a handle recess to receive a handle of pressurized tank or cylinder valve, and a torsional spring, wherein the torsional spring is configured to store potential torsional force and then release the torsional force by way of a timed release mechanism. The mechanical device comprises a securing device for securing the mechanical device to a tank or cylinder. Torsional force may be stored in torsional spring by way of a ratchet and pawl that also is configured to release the stored torsional force by way of a timed release.