Introduction to the Application and Drills of Manual Bell Alarm Systems

The hand-cranked alarm operates by manually turning an uncertain handle, which then engages a gear box to progressively increase speed. This speed is further amplified by a drive block, causing the siren wheel to work at high speed. During this high-speed operation, the siren wheel compresses and forces air out of a fixed window onto the stationary wheel, creating a consensus, which then triggers the alarm.

Hand-cranked alarm devices are commonly used for emergency alerting in sudden incidents, as they are convenient to carry. They are primarily employed in flood prevention, disaster relief, forest firefighting, and public and industrial settings for emergency alarm applications. Traditional alarms operate using shock sensors, which trigger an automatic alarm once they detect a shock signal. This means that thunderstorms, rain, or even pets touching, or other vehicles parked nearby can cause the alarm to respond. Let me introduce to you an evacuation drill using hand-cranked alarms:

Zhenjiang Taohuawu Kindergarten Conducts Earthquake Evacuation Drills for Teachers and Students

The Health Road Street Peach Blossom Community, in collaboration with the Peach Blossom Kindergarten, hosted a disaster prevention and reduction earthquake evacuation drill, with over 260 teachers, students, and residents participating.

At 10:10 a.m., as the first alarm sounded, the simulation of an earthquake began. Kindergarten teachers quickly informed the children that an "earthquake" had occurred, instructing them to crouch under their desks immediately and stay still. Approximately two minutes later, after the tremors subsided, the hand-cranked alarm sounded for the second time. The teachers led the children in an evacuation along the pre-planned疏散路线 route, with everyone reaching the large playground safely in about 5 minutes. Following the evacuation, community staff distributed promotional materials for the children to take home and read to their parents.

Civil Defense Bureau Director Zhang Jianbing observed the scene and commented, "Regularly conducting emergency evacuation drills of this kind enables teachers and students to master the correct earthquake-avoidance and evacuation methods, thus enabling them to calmly handle emergencies."