| 摘要 |
A preferred siren including a base having a central axis and a peripheral wall circumscribed about the central axis to define an internal chamber. The peripheral wall includes a plurality of apertures in communication with the internal chamber. A rotor is disposed within the chamber and centrally aligned with the axis. The rotor includes a plurality of spaced apart fins radially disposed about the axis, each of the plurality of fins having an outermost portion at a peripheral edge of the rotor and an innermost portion located between the axis and the peripheral edge. An external housing cooperates with the base to enclose the rotor within the internal chamber, the external housing including a first plurality of ports and a second plurality of ports, the first and second plurality of ports being in fluid communication with the internal chamber of the base. A driver is coupled to the rotor and is powered by a supply of carbon-dioxide gas to rotate the rotor about the axis at a rotational speed such that external air is drawn through the first plurality of ports, into the chamber and out the second plurality of ports so as to generate an alarm sound having an intensity greater than 100 decibels (100 dB). |
