Application of Life Detector in Person Search and Rescue

【Abstract】In order to prevent buildings from collapsing due to earthquake disasters, explosions, or other reasons, based on “fighting big battles and fighting hardships”, the fighting power of fire fighting units in dealing with the collapse of various types of buildings will be improved. Accurate search and rescue personnel trapped in a short time, the number of casualties to the lowest ", life detector" has become one of the most frequently used equipment for firefighting troops in search and rescue work.

【Key Words】 Building Collapse Search and Rescue Life Detector

1 Principle of Life Detector

Life detector is currently the most advanced search and rescue and detection instrument in the world. It mainly finds the “living person” position by sensing the electric field (generated by the heart) generated by ultra-low-frequency waves emitted by the human body. The ultra-low frequency electric field emitted by the human body can penetrate reinforced concrete walls, steel plates, planks, and even water. Therefore, as long as there are signs of life, whether it is awake, unconscious, trapped in a rubble, or hiding in a container, a life detector can be used. Find it in the shortest possible time. The life detector has an open detection range of up to 500 meters and can detect life through ordinary steel plates 80 centimeters thick.

2 Classification of Life Detectors

Life detectors can be divided into radar wave detectors , video detectors , and audio detectors based on the principle structure. They are compared as follows:

Audio Detector : Acoustic Audio Detector - Detects the target by acquiring weak sound waves propagating in the air and amplifying the signal; Shock Wave Audio Detector - Detects the target by picking up and amplifying the shock wave from the ground through the vibration probe; both Common features are: lower prices, more simple and easy to use.

Audio detector

Limitations: The site needs to have certain holes and fissures to reach into the detection equipment, or it can only be applied to the detection of shallow surface and large space. In the case of rain or fire water, it will be subject to certain environmental disturbances.

Video Detector - Uses visible light or non-visible light for imaging through a CCD sensor. With video visualization, intuitive, simple, easy to use, inexpensive, generally in the use of cable to transmit audio signals, or slot holes.

Video detector

Radar Life Detector —Electromagnetic waves are emitted from the radar antenna in a concentrated and directed manner. The electromagnetic waves can penetrate concrete walls, gravel, rubble, etc., and reflect and change after contact with the human body. Because this change is affected by human physical activity, breathing, or even heartbeat activity, electromagnetic waves that have changed after reflection are received by the receiver. After filtering the background interference, certain unique spectrums are analyzed and processed by computer software and displayed on the display screen. With features that are easy to carry, fast to move, and do not need to come into contact with objects, they do not need to be penetrated by holes, crevices, etc., and trapped persons can be detected when covered with various substances.

Radar detector

Life detection radar consists of a wireless probe transmitter and a handheld computer. The wireless probing transmitter first transmits radar waves. The radar waves can penetrate common building walls and gravel and other materials and reach the measured target up to 6 meters away. The movement of the target or the respiratory heartbeat causes a certain change in the radar wave, and sends the changed radar wave back to the PDA via the antenna. After the data processing of the professional software in the computer, the corresponding waveform diagram and signal display are obtained to judge whether there are survivors within the measured range. When operating the detection radar, make sure that the distance between the handheld computer and the wireless detection transmitter is in the range of 1.5 to 15 meters and that there is no other suspicious movement within 6.1 meters from the detector antenna. The device can usually complete the search in the effective space within 3 minutes and further locate the trapped people.

3 Comparison between life detectors

Different types of life detectors have different detection effects depending on the principle. The performance comparison of different types of life detectors shown in Table 1 lists that all types of existing life detectors can only collect vital sign information for the environment within a certain region after the earthquake, and cannot collect and process the collected information in each region. Therefore, it is necessary to Comprehensive information collected by various types of life detectors can provide the basis for the further development of rescue plans (Table 1).

On the whole, science and technology have extended our vision and hearing. In different environments and different fields, various life detectors have their own advantages and strengths. However, with the rapid development of economic construction in our city, disaster accidents have occurred. The relatively backward contradiction between frequency and social disaster relief capacity has become increasingly prominent. Modern cities and modern industries have brought new challenges. The number of high-rise, underground and large spaces, special-shaped buildings, and flammable and explosive units has increased, and rescue missions have become more difficult. Intensifying, the severe situation requires that we must build a strong fire-fighting iron troop team that is “come on and coming, able to fight, and win the battle” to undertake emergency, difficult, dangerous and heavy social disaster relief missions. .

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.