The working principle of the defender's air defense alarm is that the petrol engine drives the high-speed rotation of the firing wheel, and the general speed is about 2880r / min; when the motor drives the turning wheel, air enters the firing wheel from the side air inlet, which generates high-speed air absorption. Resonance caused by the simultaneous extrusion of high pressure towards the fixed window.

1. Defender siren test sound transmission radius: 8km

2. The population density of eastern China is 2229 people / km2;

     Sound coverage: s = πr2 = 3.14 × 8 × 8 = 200.96 square kilometers

    200.96 × 2229 = 447939 people (beneficiaries)

As a professional life-saving equipment for ship-to-ship, shore-to-ship, high-rise and mountain streamline rescue, life-saving throwers are increasingly used in emergency rescue work of fire forces. The main direction of our research and development is throwing distance, throwing accuracy and throwing times. The first generation of products was launched in the market at the end of 2014.

The latest developed precision thrower at the end of 2016 set a precedent for remotely launching throwers. The maximum throwing distance of this product is up to 250M. The position of the throwing device is accurate. The launching of the projectile can be intelligently controlled by VR glasses and electronic handwheels. It can also capture unmanned access. The application range is also wider. Anti-terrorism, marine rescue, fire rescue, etc. can be applied. On April 27, 2017, it was broadcasted on CCTV's 10 sets of "I Love Inventions". Our researcher, Wang Liangren, was also awarded the prize by the secretary of the Taizhou Municipal Party Committee Wang Changrong: the grassroots inventor.

Product features of precision thrower:

1. High degree of intelligence. The controller adjusts the position and angle of the ejection device according to the set data and data collected from the outside, so that the ejection is more accurate and unnecessary waste of time can be avoided during the rescue process.

2. The muzzle velocity is high and the launch distance is long. The rescue bomb has a tail fin, which has good wind resistance and high launch accuracy. The maximum throwing distance is 250 meters.

3. It has a wide range of applications and can be used for life-saving occasions or cable installation and wiring of power systems or anti-terrorism occasions or capture of drones.